LAB 4 IS DONE.

lab/LAB4.si4project/Backup/dumbfork(162).c

@@ -0,0 +1,80 @@
+// Ping-pong a counter between two processes.
+// Only need to start one of these -- splits into two, crudely.
+
+#include <inc/string.h>
+#include <inc/lib.h>
+
+envid_t dumbfork(void);
+
+void
+umain(int argc, char **argv)
+{
+	envid_t who;
+	int i;
+
+	// fork a child process
+	who = dumbfork();
+
+	// print a message and yield to the other a few times
+	for (i = 0; i < (who ? 10 : 20); i++) {
+		cprintf("%d: I am the %s!\n", i, who ? "parent" : "child");
+		sys_yield();
+	}
+}
+
+void
+duppage(envid_t dstenv, void *addr)
+{
+	int r;
+
+	// This is NOT what you should do in your fork.
+	if ((r = sys_page_alloc(dstenv, addr, PTE_P|PTE_U|PTE_W)) < 0)
+		panic("sys_page_alloc: %e", r);
+	if ((r = sys_page_map(dstenv, addr, 0, UTEMP, PTE_P|PTE_U|PTE_W)) < 0)
+		panic("sys_page_map: %e", r);
+	memmove(UTEMP, addr, PGSIZE);
+	if ((r = sys_page_unmap(0, UTEMP)) < 0)
+		panic("sys_page_unmap: %e", r);
+}
+
+envid_t
+dumbfork(void)
+{
+	envid_t envid;
+	uint8_t *addr;
+	int r;
+	extern unsigned char end[];
+
+	// Allocate a new child environment.
+	// The kernel will initialize it with a copy of our register state,
+	// so that the child will appear to have called sys_exofork() too -
+	// except that in the child, this "fake" call to sys_exofork()
+	// will return 0 instead of the envid of the child.
+	envid = sys_exofork();
+	if (envid < 0)
+		panic("sys_exofork: %e", envid);
+	if (envid == 0) {
+		// We're the child.
+		// The copied value of the global variable 'thisenv'
+		// is no longer valid (it refers to the parent!).
+		// Fix it and return 0.
+		thisenv = &envs[ENVX(sys_getenvid())];
+		return 0;
+	}
+
+	// We're the parent.
+	// Eagerly copy our entire address space into the child.
+	// This is NOT what you should do in your fork implementation.
+	for (addr = (uint8_t*) UTEXT; addr < end; addr += PGSIZE)
+		duppage(envid, addr);
+
+	// Also copy the stack we are currently running on.
+	duppage(envid, ROUNDDOWN(&addr, PGSIZE));
+
+	// Start the child environment running
+	if ((r = sys_env_set_status(envid, ENV_RUNNABLE)) < 0)
+		panic("sys_env_set_status: %e", r);
+
+	return envid;
+}
+

lab/LAB4.si4project/Backup/dumbfork(7443).c

@@ -0,0 +1,80 @@
+// Ping-pong a counter between two processes.
+// Only need to start one of these -- splits into two, crudely.
+
+#include <inc/string.h>
+#include <inc/lib.h>
+
+envid_t dumbfork(void);
+
+void
+umain(int argc, char **argv)
+{
+	envid_t who;
+	int i;
+
+	// fork a child process
+	who = dumbfork();
+
+	// print a message and yield to the other a few times
+	for (i = 0; i < (who ? 10 : 20); i++) {
+		cprintf("%d: I am the %s!\n", i, who ? "parent" : "child");
+		sys_yield();
+	}
+}
+
+void
+duppage(envid_t dstenv, void *addr)
+{
+	int r;
+
+	// This is NOT what you should do in your fork.
+	if ((r = sys_page_alloc(dstenv, addr, PTE_P|PTE_U|PTE_W)) < 0)
+		panic("sys_page_alloc: %e", r);
+	if ((r = sys_page_map(dstenv, addr, 0, UTEMP, PTE_P|PTE_U|PTE_W)) < 0)
+		panic("sys_page_map: %e", r);
+	memmove(UTEMP, addr, PGSIZE);
+	if ((r = sys_page_unmap(0, UTEMP)) < 0)
+		panic("sys_page_unmap: %e", r);
+}
+
+envid_t
+dumbfork(void)
+{
+	envid_t envid;
+	uint8_t *addr;
+	int r;
+	extern unsigned char end[];
+
+	// Allocate a new child environment.
+	// The kernel will initialize it with a copy of our register state,
+	// so that the child will appear to have called sys_exofork() too -
+	// except that in the child, this "fake" call to sys_exofork()
+	// will return 0 instead of the envid of the child.
+	envid = sys_exofork();
+	if (envid < 0)
+		panic("sys_exofork: %e", envid);
+	if (envid == 0) {
+		// We're the child.
+		// The copied value of the global variable 'thisenv'
+		// is no longer valid (it refers to the parent!).
+		// Fix it and return 0.
+		thisenv = &envs[ENVX(sys_getenvid())];
+		return 0;
+	}
+
+	// We're the parent.
+	// Eagerly copy our entire address space into the child.
+	// This is NOT what you should do in your fork implementation.
+	for (addr = (uint8_t*) UTEXT; addr < end; addr += PGSIZE)
+		duppage(envid, addr);
+
+	// Also copy the stack we are currently running on.
+	duppage(envid, ROUNDDOWN(&addr, PGSIZE));
+
+	// Start the child environment running
+	if ((r = sys_env_set_status(envid, ENV_RUNNABLE)) < 0)
+		panic("sys_env_set_status: %e", r);
+
+	return envid;
+}
+

lab/LAB4.si4project/Backup/dumbfork(8040).c

@@ -0,0 +1,89 @@
+// Ping-pong a counter between two processes.
+// Only need to start one of these -- splits into two, crudely.
+
+#include <inc/string.h>
+#include <inc/lib.h>
+
+envid_t dumbfork(void);
+
+void
+umain(int argc, char **argv)
+{
+	envid_t who;
+	int i;
+
+	// fork a child process
+	who = dumbfork();
+
+	// print a message and yield to the other a few times
+	for (i = 0; i < (who ? 10 : 20); i++) {
+		cprintf("%d: I am the %s!\n", i, who ? "parent" : "child");
+		sys_yield();
+	}
+}
+
+void
+duppage(envid_t dstenv, void *addr)
+{
+	int r;
+
+	// This is NOT what you should do in your fork.
+	if ((r = sys_page_alloc(dstenv, addr, PTE_P|PTE_U|PTE_W)) < 0)
+		panic("sys_page_alloc: %e", r);
+	// dstenv 的 addr 映射到 envs[0]的UTEMP，
+	if ((r = sys_page_map(dstenv, addr, 0, UTEMP, PTE_P|PTE_U|PTE_W)) < 0)
+		panic("sys_page_map: %e", r);
+
+	memmove(UTEMP, addr, PGSIZE);
+	if ((r = sys_page_unmap(0, UTEMP)) < 0)
+		panic("sys_page_unmap: %e", r);
+}
+
+envid_t
+dumbfork(void)
+{
+	envid_t envid;
+	uint8_t *addr;
+	int r;
+	extern unsigned char end[];
+
+	// Allocate a new child environment.
+	// The kernel will initialize it with a copy of our register state,
+	// so that the child will appear to have called sys_exofork() too -
+	// except that in the child, this "fake" call to sys_exofork()
+	// will return 0 instead of the envid of the child.
+	envid = sys_exofork();
+	cprintf("envid: %d\n",envid);
+	if (envid < 0)
+		panic("sys_exofork: %e", envid);
+	if (envid == 0) {
+		// We're the child.
+		// The copied value of the global variable 'thisenv'
+		// is no longer valid (it refers to the parent!).
+		// Fix it and return 0.
+		// "child, sysgetenvid() : 1
+		// cprintf("child, sysgetenvid() :%d\n", ENVX(sys_getenvid()));
+		thisenv = &envs[ENVX(sys_getenvid())];
+		return 0;
+	}
+
+	// We're the parent.
+	// Eagerly copy our entire address space into the child.
+	// This is NOT what you should do in your fork implementation.
+	for (addr = (uint8_t*) UTEXT; addr < end; addr += PGSIZE) {
+		// copying addr :00800000
+		// copying addr :00801000
+		// copying addr :00802000
+		cprintf("copying addr :%08x\n", (uint32_t)addr);	
+		duppage(envid, addr);
+	}
+	// Also copy the stack we are currently running on.
+	duppage(envid, ROUNDDOWN(&addr, PGSIZE));
+
+	// Start the child environment running
+	if ((r = sys_env_set_status(envid, ENV_RUNNABLE)) < 0)
+		panic("sys_env_set_status: %e", r);
+
+	return envid;
+}
+

lab/LAB4.si4project/Backup/entry(6508).S

@@ -0,0 +1,35 @@
+#include <inc/mmu.h>
+#include <inc/memlayout.h>
+
+.data
+// Define the global symbols 'envs', 'pages', 'uvpt', and 'uvpd'
+// so that they can be used in C as if they were ordinary global arrays.
+	.globl envs
+	.set envs, UENVS
+	.globl pages
+	.set pages, UPAGES
+	.globl uvpt
+	.set uvpt, UVPT
+	.globl uvpd
+	.set uvpd, (UVPT+(UVPT>>12)*4)
+
+
+// Entrypoint - this is where the kernel (or our parent environment)
+// starts us running when we are initially loaded into a new environment.
+.text
+.globl _start
+_start:
+	// See if we were started with arguments on the stack
+	cmpl $USTACKTOP, %esp
+	jne args_exist
+
+	// If not, push dummy argc/argv arguments.
+	// This happens when we are loaded by the kernel,
+	// because the kernel does not know about passing arguments.
+	pushl $0
+	pushl $0
+
+args_exist:
+	call libmain
+1:	jmp 1b
+

lab/LAB4.si4project/Backup/env(1818).c

@@ -0,0 +1,569 @@
+/* See COPYRIGHT for copyright information. */
+
+#include <inc/x86.h>
+#include <inc/mmu.h>
+#include <inc/error.h>
+#include <inc/string.h>
+#include <inc/assert.h>
+#include <inc/elf.h>
+
+#include <kern/env.h>
+#include <kern/pmap.h>
+#include <kern/trap.h>
+#include <kern/monitor.h>
+#include <kern/sched.h>
+#include <kern/cpu.h>
+#include <kern/spinlock.h>
+
+struct Env *envs = NULL;		// All environments
+static struct Env *env_free_list;	// Free environment list
+					// (linked by Env->env_link)
+
+#define ENVGENSHIFT	12		// >= LOGNENV
+
+// Global descriptor table.
+//
+// Set up global descriptor table (GDT) with separate segments for
+// kernel mode and user mode.  Segments serve many purposes on the x86.
+// We don't use any of their memory-mapping capabilities, but we need
+// them to switch privilege levels. 
+//
+// The kernel and user segments are identical except for the DPL.
+// To load the SS register, the CPL must equal the DPL.  Thus,
+// we must duplicate the segments for the user and the kernel.
+//
+// In particular, the last argument to the SEG macro used in the
+// definition of gdt specifies the Descriptor Privilege Level (DPL)
+// of that descriptor: 0 for kernel and 3 for user.
+//
+struct Segdesc gdt[NCPU + 5] =
+{
+	// 0x0 - unused (always faults -- for trapping NULL far pointers)
+	SEG_NULL,
+
+	// 0x8 - kernel code segment
+	[GD_KT >> 3] = SEG(STA_X | STA_R, 0x0, 0xffffffff, 0),
+
+	// 0x10 - kernel data segment
+	[GD_KD >> 3] = SEG(STA_W, 0x0, 0xffffffff, 0),
+
+	// 0x18 - user code segment
+	[GD_UT >> 3] = SEG(STA_X | STA_R, 0x0, 0xffffffff, 3),
+
+	// 0x20 - user data segment
+	[GD_UD >> 3] = SEG(STA_W, 0x0, 0xffffffff, 3),
+
+	// Per-CPU TSS descriptors (starting from GD_TSS0) are initialized
+	// in trap_init_percpu()
+	[GD_TSS0 >> 3] = SEG_NULL
+};
+
+struct Pseudodesc gdt_pd = {
+	sizeof(gdt) - 1, (unsigned long) gdt
+};
+
+//
+// Converts an envid to an env pointer.
+// If checkperm is set, the specified environment must be either the
+// current environment or an immediate child of the current environment.
+//
+// RETURNS
+//   0 on success, -E_BAD_ENV on error.
+//   On success, sets *env_store to the environment.
+//   On error, sets *env_store to NULL.
+//
+int
+envid2env(envid_t envid, struct Env **env_store, bool checkperm)
+{
+	struct Env *e;
+
+	// If envid is zero, return the current environment.
+	if (envid == 0) {
+		*env_store = curenv;
+		return 0;
+	}
+
+	// Look up the Env structure via the index part of the envid,
+	// then check the env_id field in that struct Env
+	// to ensure that the envid is not stale
+	// (i.e., does not refer to a _previous_ environment
+	// that used the same slot in the envs[] array).
+	e = &envs[ENVX(envid)];
+	if (e->env_status == ENV_FREE || e->env_id != envid) {
+		*env_store = 0;
+		return -E_BAD_ENV;
+	}
+
+	// Check that the calling environment has legitimate permission
+	// to manipulate the specified environment.
+	// If checkperm is set, the specified environment
+	// must be either the current environment
+	// or an immediate child of the current environment.
+	if (checkperm && e != curenv && e->env_parent_id != curenv->env_id) {
+		*env_store = 0;
+		return -E_BAD_ENV;
+	}
+
+	*env_store = e;
+	return 0;
+}
+
+// Mark all environments in 'envs' as free, set their env_ids to 0,
+// and insert them into the env_free_list.
+// Make sure the environments are in the free list in the same order
+// they are in the envs array (i.e., so that the first call to
+// env_alloc() returns envs[0]).
+//
+void
+env_init(void)
+{
+	// Set up envs array
+	// LAB 3: Your code here.
+	int i;
+	// 确保最小的env在最前端
+	for (i = NENV-1; i >= 0; --i) {
+		envs[i].env_id = 0;
+	
+		envs[i].env_link = env_free_list;
+		env_free_list = &envs[i];
+	}
+	
+	// Per-CPU part of the initialization
+	env_init_percpu();
+}
+
+// Load GDT and segment descriptors.
+void
+env_init_percpu(void)
+{
+	lgdt(&gdt_pd);
+	// The kernel never uses GS or FS, so we leave those set to
+	// the user data segment.
+	asm volatile("movw %%ax,%%gs" : : "a" (GD_UD|3));
+	asm volatile("movw %%ax,%%fs" : : "a" (GD_UD|3));
+	// The kernel does use ES, DS, and SS.  We'll change between
+	// the kernel and user data segments as needed.
+	asm volatile("movw %%ax,%%es" : : "a" (GD_KD));
+	asm volatile("movw %%ax,%%ds" : : "a" (GD_KD));
+	asm volatile("movw %%ax,%%ss" : : "a" (GD_KD));
+	// Load the kernel text segment into CS.
+	asm volatile("ljmp %0,$1f\n 1:\n" : : "i" (GD_KT));
+	// For good measure, clear the local descriptor table (LDT),
+	// since we don't use it.
+	lldt(0);
+}
+
+//
+// Initialize the kernel virtual memory layout for environment e.
+// Allocate a page directory, set e->env_pgdir accordingly,
+// and initialize the kernel portion of the new environment's address space.
+// Do NOT (yet) map anything into the user portion
+// of the environment's virtual address space.
+//
+// Returns 0 on success, < 0 on error.  Errors include:
+//	-E_NO_MEM if page directory or table could not be allocated.
+//  这里又为每个环境分配一个页目录，有点晕了。
+static int
+env_setup_vm(struct Env *e)
+{
+	int i;
+	struct PageInfo *p = NULL;
+
+	// Allocate a page for the page directory
+	if (!(p = page_alloc(ALLOC_ZERO)))
+		return -E_NO_MEM;
+
+	// Now, set e->env_pgdir and initialize the page directory.
+	//
+	// Hint:
+	//    - The VA space of all envs is identical above UTOP
+	//	(except at UVPT, which we've set below).
+	//	See inc/memlayout.h for permissions and layout.
+	//	Can you use kern_pgdir as a template?  Hint: Yes.
+	//	(Make sure you got the permissions right in Lab 2.)
+	//    - The initial VA below UTOP is empty.
+	//    - You do not need to make any more calls to page_alloc.
+	//    - Note: In general, pp_ref is not maintained for
+	//	physical pages mapped only above UTOP, but env_pgdir
+	//	is an exception -- you need to increment env_pgdir's
+	//	pp_ref for env_free to work correctly.
+	//    - The functions in kern/pmap.h are handy.
+
+	
+	// LAB 3: Your code here.
+	// 申请一个页表存用户环境的页目录
+	
+	e->env_pgdir = page2kva(p);
+	// why ?因为在UTOP之上都是一样的，所以可以直接把kern_pgdir的内容全部拷贝过来
+    
+	memcpy(e->env_pgdir, kern_pgdir, PGSIZE);
+	p->pp_ref++;
+	// UVPT maps the env's own page table read-only.
+	// Permissions: kernel R, user R
+	// 但是唯独UVPT这个地方是不一样的，因为要放的是自己的页表目录
+	e->env_pgdir[PDX(UVPT)] = PADDR(e->env_pgdir) | PTE_P | PTE_U;
+
+	return 0;
+}
+
+//
+// Allocates and initializes a new environment.
+// On success, the new environment is stored in *newenv_store.
+//
+// Returns 0 on success, < 0 on failure.  Errors include:
+//	-E_NO_FREE_ENV if all NENV environments are allocated
+//	-E_NO_MEM on memory exhaustion
+//
+int
+env_alloc(struct Env **newenv_store, envid_t parent_id)
+{
+	int32_t generation;
+	int r;
+	struct Env *e;
+
+	if (!(e = env_free_list))
+		return -E_NO_FREE_ENV;
+
+	// Allocate and set up the page directory for this environment.
+	if ((r = env_setup_vm(e)) < 0)
+		return r;
+
+	// Generate an env_id for this environment.
+	generation = (e->env_id + (1 << ENVGENSHIFT)) & ~(NENV - 1);
+	if (generation <= 0)	// Don't create a negative env_id.
+		generation = 1 << ENVGENSHIFT;
+	e->env_id = generation | (e - envs);
+
+	// Set the basic status variables.
+	e->env_parent_id = parent_id;
+	e->env_type = ENV_TYPE_USER;
+	e->env_status = ENV_RUNNABLE;
+	e->env_runs = 0;
+
+	// Clear out all the saved register state,
+	// to prevent the register values
+	// of a prior environment inhabiting this Env structure
+	// from "leaking" into our new environment.
+	memset(&e->env_tf, 0, sizeof(e->env_tf));
+
+	// Set up appropriate initial values for the segment registers.
+	// GD_UD is the user data segment selector in the GDT, and
+	// GD_UT is the user text segment selector (see inc/memlayout.h).
+	// The low 2 bits of each segment register contains the
+	// Requestor Privilege Level (RPL); 3 means user mode.  When
+	// we switch privilege levels, the hardware does various
+	// checks involving the RPL and the Descriptor Privilege Level
+	// (DPL) stored in the descriptors themselves.
+	e->env_tf.tf_ds = GD_UD | 3;
+	e->env_tf.tf_es = GD_UD | 3;
+	e->env_tf.tf_ss = GD_UD | 3;
+	e->env_tf.tf_esp = USTACKTOP;
+	e->env_tf.tf_cs = GD_UT | 3;
+	// You will set e->env_tf.tf_eip later.
+
+	// Enable interrupts while in user mode.
+	// LAB 4: Your code here.
+
+	// Clear the page fault handler until user installs one.
+	e->env_pgfault_upcall = 0;
+
+	// Also clear the IPC receiving flag.
+	e->env_ipc_recving = 0;
+
+	// commit the allocation
+	env_free_list = e->env_link;
+	*newenv_store = e;
+
+	cprintf("[%08x] new env %08x\n", curenv ? curenv->env_id : 0, e->env_id);
+	return 0;
+}
+
+//
+// Allocate len bytes of physical memory for environment env,
+// and map it at virtual address va in the environment's address space.
+// Does not zero or otherwise initialize the mapped pages in any way.
+// Pages should be writable by user and kernel.
+// Panic if any allocation attempt fails.
+//
+static void
+region_alloc(struct Env *e, void *va, size_t len)
+{
+	// LAB 3: Your code here.
+	// (But only if you need it for load_icode.)
+	//
+	struct PageInfo *pp;
+	size_t i;
+	size_t pgs = ROUNDUP(len, PGSIZE)/PGSIZE;
+	size_t pva = ROUNDDOWN((size_t)va, PGSIZE);
+	
+	
+	for(i=0; i < pgs; i++) {
+		if (!(pp = page_alloc(ALLOC_ZERO))) {
+			int ex = -E_NO_MEM;
+	        panic("region_alloc: %e", ex);
+		}
+		page_insert(e->env_pgdir, pp, (void *)pva, PTE_U|PTE_W|PTE_P);
+		pva += PGSIZE;
+		
+	}
+	// Hint: It is easier to use region_alloc if the caller can pass
+	//   'va' and 'len' values that are not page-aligned.
+	//   You should round va down, and round (va + len) up.
+	//   (Watch out for corner-cases!)
+}
+
+//
+// Set up the initial program binary, stack, and processor flags
+// for a user process.
+// This function is ONLY called during kernel initialization,
+// before running the first user-mode environment.
+//
+// This function loads all loadable segments from the ELF binary image
+// into the environment's user memory, starting at the appropriate
+// virtual addresses indicated in the ELF program header.
+// At the same time it clears to zero any portions of these segments
+// that are marked in the program header as being mapped
+// but not actually present in the ELF file - i.e., the program's bss section.
+//
+// All this is very similar to what our boot loader does, except the boot
+// loader also needs to read the code from disk.  Take a look at
+// boot/main.c to get ideas.
+//
+// Finally, this function maps one page for the program's initial stack.
+//
+// load_icode panics if it encounters problems.
+//  - How might load_icode fail?  What might be wrong with the given input?
+//
+static void
+load_icode(struct Env *e, uint8_t *binary)
+{
+	// Hints:
+	//  Load each program segment into virtual memory
+	//  at the address specified in the ELF segment header.
+	//  You should only load segments with ph->p_type == ELF_PROG_LOAD.
+	//  Each segment's virtual address can be found in ph->p_va
+	//  and its size in memory can be found in ph->p_memsz.
+	//  The ph->p_filesz bytes from the ELF binary, starting at
+	//  'binary + ph->p_offset', should be copied to virtual address
+	//  ph->p_va.  Any remaining memory bytes should be cleared to zero.
+	//  (The ELF header should have ph->p_filesz <= ph->p_memsz.)
+	//  Use functions from the previous lab to allocate and map pages.
+	//
+	//  All page protection bits should be user read/write for now.
+	//  ELF segments are not necessarily page-aligned, but you can
+	//  assume for this function that no two segments will touch
+	//  the same virtual page.
+	//
+	//  You may find a function like region_alloc useful.
+	//
+	//  Loading the segments is much simpler if you can move data
+	//  directly into the virtual addresses stored in the ELF binary.
+	//  So which page directory should be in force during
+	//  this function?
+	//
+	//  You must also do something with the program's entry point,
+	//  to make sure that the environment starts executing there.
+	//  What?  (See env_run() and env_pop_tf() below.)
+
+	// LAB 3: Your code here.
+	// 怎么得到program的ELF地址? 就是bianry
+	struct Proghdr *ph, *eph;
+	struct Elf *elfhdr = (struct Elf *)binary;
+	
+	// is this a valid ELF?
+	if (elfhdr->e_magic != ELF_MAGIC)
+		panic("elf header's magic is not correct\n");
+
+	// 所有程序段 
+	ph = (struct Proghdr *)((uint8_t *)elfhdr + elfhdr->e_phoff);
+	eph = ph + elfhdr->e_phnum;
+	// 转换到用户页目录，用户空间映射
+	lcr3(PADDR(e->env_pgdir));
+	
+	for(; ph < eph; ph++) {
+		
+		if (ph->p_type != ELF_PROG_LOAD)
+			continue;
+		if (ph->p_filesz > ph->p_memsz)
+			panic("file size is great than memmory size\n");
+
+		region_alloc(e, (void *)ph->p_va, ph->p_memsz);
+		memcpy((void *)ph->p_va, binary + ph->p_offset, ph->p_filesz);
+		// clear bss section
+		memset((void *)ph->p_va + ph->p_filesz, 0, (ph->p_memsz - ph->p_filesz));
+			
+	}
+	e->env_tf.tf_eip = elfhdr->e_entry;
+	// Now map one page for the program's initial stack
+	// at virtual address USTACKTOP - PGSIZE.
+	
+	// LAB 3: Your code here.
+	
+	// map the user stack
+	region_alloc(e, (void *)USTACKTOP-PGSIZE, PGSIZE);
+	lcr3(PADDR(kern_pgdir));
+}
+
+//
+// Allocates a new env with env_alloc, loads the named elf
+// binary into it with load_icode, and sets its env_type.
+// This function is ONLY called during kernel initialization,
+// before running the first user-mode environment.
+// The new env's parent ID is set to 0.
+//
+void
+env_create(uint8_t *binary, enum EnvType type)
+{
+	// LAB 3: Your code here.
+	struct Env *newenv;
+	int ret = 0;
+	if ((ret = env_alloc(&newenv, 0)) < 0) {
+		panic("env_create: %e\n", ret);
+	}
+	newenv->env_type = type;
+	load_icode(newenv, binary);
+	
+}
+
+//
+// Frees env e and all memory it uses.
+//
+void
+env_free(struct Env *e)
+{
+	pte_t *pt;
+	uint32_t pdeno, pteno;
+	physaddr_t pa;
+
+	// If freeing the current environment, switch to kern_pgdir
+	// before freeing the page directory, just in case the page
+	// gets reused.
+	if (e == curenv)
+		lcr3(PADDR(kern_pgdir));
+
+	// Note the environment's demise.
+	cprintf("[%08x] free env %08x\n", curenv ? curenv->env_id : 0, e->env_id);
+
+	// Flush all mapped pages in the user portion of the address space
+	static_assert(UTOP % PTSIZE == 0);
+	for (pdeno = 0; pdeno < PDX(UTOP); pdeno++) {
+
+		// only look at mapped page tables
+		if (!(e->env_pgdir[pdeno] & PTE_P))
+			continue;
+
+		// find the pa and va of the page table
+		pa = PTE_ADDR(e->env_pgdir[pdeno]);
+		pt = (pte_t*) KADDR(pa);
+
+		// unmap all PTEs in this page table
+		for (pteno = 0; pteno <= PTX(~0); pteno++) {
+			if (pt[pteno] & PTE_P)
+				page_remove(e->env_pgdir, PGADDR(pdeno, pteno, 0));
+		}
+
+		// free the page table itself
+		e->env_pgdir[pdeno] = 0;
+		page_decref(pa2page(pa));
+	}
+
+	// free the page directory
+	pa = PADDR(e->env_pgdir);
+	e->env_pgdir = 0;
+	page_decref(pa2page(pa));
+
+	// return the environment to the free list
+	e->env_status = ENV_FREE;
+	e->env_link = env_free_list;
+	env_free_list = e;
+}
+
+//
+// Frees environment e.
+// If e was the current env, then runs a new environment (and does not return
+// to the caller).
+//
+void
+env_destroy(struct Env *e)
+{
+	// If e is currently running on other CPUs, we change its state to
+	// ENV_DYING. A zombie environment will be freed the next time
+	// it traps to the kernel.
+	if (e->env_status == ENV_RUNNING && curenv != e) {
+		e->env_status = ENV_DYING;
+		return;
+	}
+
+	env_free(e);
+
+	if (curenv == e) {
+		curenv = NULL;
+		sched_yield();
+	}
+}
+
+
+//
+// Restores the register values in the Trapframe with the 'iret' instruction.
+// This exits the kernel and starts executing some environment's code.
+//
+// This function does not return.
+//
+void
+env_pop_tf(struct Trapframe *tf)
+{
+	// Record the CPU we are running on for user-space debugging
+	curenv->env_cpunum = cpunum();
+
+	asm volatile(
+		"\tmovl %0,%%esp\n"
+		"\tpopal\n"
+		"\tpopl %%es\n"
+		"\tpopl %%ds\n"
+		"\taddl $0x8,%%esp\n" /* skip tf_trapno and tf_errcode */
+		"\tiret\n"
+		: : "g" (tf) : "memory");
+	panic("iret failed");  /* mostly to placate the compiler */
+}
+
+//
+// Context switch from curenv to env e.
+// Note: if this is the first call to env_run, curenv is NULL.
+//
+// This function does not return.
+//
+void
+env_run(struct Env *e)
+{
+	// Step 1: If this is a context switch (a new environment is running):
+	//	   1. Set the current environment (if any) back to
+	//	      ENV_RUNNABLE if it is ENV_RUNNING (think about
+	//	      what other states it can be in),
+	//	   2. Set 'curenv' to the new environment,
+	//	   3. Set its status to ENV_RUNNING,
+	//	   4. Update its 'env_runs' counter,
+	//	   5. Use lcr3() to switch to its address space.
+	// Step 2: Use env_pop_tf() to restore the environment's
+	//	   registers and drop into user mode in the
+	//	   environment.
+
+	// Hint: This function loads the new environment's state from
+	//	e->env_tf.  Go back through the code you wrote above
+	//	and make sure you have set the relevant parts of
+	//	e->env_tf to sensible values.
+
+	// LAB 3: Your code here.
+	if (curenv && curenv->env_status == ENV_RUNNING) {
+		curenv->env_status = ENV_RUNNABLE;
+	}
+	curenv = e;
+	curenv->env_status = ENV_RUNNING;
+	curenv->env_runs++;
+	lcr3(PADDR(curenv->env_pgdir));
+	// 将当前进程的trapframe通过弹栈的形式，切换当前的运行环境
+	env_pop_tf(&(curenv->env_tf));
+
+	unlock_kernel();
+	// panic("env_run not yet implemented");
+}
+

lab/LAB4.si4project/Backup/env(4388).h

@@ -0,0 +1,70 @@
+/* See COPYRIGHT for copyright information. */
+
+#ifndef JOS_INC_ENV_H
+#define JOS_INC_ENV_H
+
+#include <inc/types.h>
+#include <inc/trap.h>
+#include <inc/memlayout.h>
+
+typedef int32_t envid_t;
+
+// An environment ID 'envid_t' has three parts:
+//
+// +1+---------------21-----------------+--------10--------+
+// |0|          Uniqueifier             |   Environment    |
+// | |                                  |      Index       |
+// +------------------------------------+------------------+
+//                                       \--- ENVX(eid) --/
+//
+// The environment index ENVX(eid) equals the environment's index in the
+// 'envs[]' array.  The uniqueifier distinguishes environments that were
+// created at different times, but share the same environment index.
+//
+// All real environments are greater than 0 (so the sign bit is zero).
+// envid_ts less than 0 signify errors.  The envid_t == 0 is special, and
+// stands for the current environment.
+
+#define LOG2NENV		10
+#define NENV			(1 << LOG2NENV)
+#define ENVX(envid)		((envid) & (NENV - 1))
+
+// Values of env_status in struct Env
+enum {
+	ENV_FREE = 0,
+	ENV_DYING,
+	ENV_RUNNABLE,
+	ENV_RUNNING,
+	ENV_NOT_RUNNABLE
+};
+
+// Special environment types
+enum EnvType {
+	ENV_TYPE_USER = 0,
+};
+
+struct Env {
+	struct Trapframe env_tf;	// Saved registers
+	struct Env *env_link;		// Next free Env
+	envid_t env_id;			// Unique environment identifier
+	envid_t env_parent_id;		// env_id of this env's parent
+	enum EnvType env_type;		// Indicates special system environments
+	unsigned env_status;		// Status of the environment
+	uint32_t env_runs;		// Number of times environment has run
+	int env_cpunum;			// The CPU that the env is running on
+
+	// Address space
+	pde_t *env_pgdir;		// Kernel virtual address of page dir
+
+	// Exception handling
+	void *env_pgfault_upcall;	// Page fault upcall entry point
+
+	// Lab 4 IPC
+	bool env_ipc_recving;		// Env is blocked receiving
+	void *env_ipc_dstva;		// VA at which to map received page
+	uint32_t env_ipc_value;		// Data value sent to us
+	envid_t env_ipc_from;		// envid of the sender
+	int env_ipc_perm;		// Perm of page mapping received
+};
+
+#endif // !JOS_INC_ENV_H

lab/LAB4.si4project/Backup/env(572).c

@@ -0,0 +1,572 @@
+/* See COPYRIGHT for copyright information. */
+
+#include <inc/x86.h>
+#include <inc/mmu.h>
+#include <inc/error.h>
+#include <inc/string.h>
+#include <inc/assert.h>
+#include <inc/elf.h>
+
+#include <kern/env.h>
+#include <kern/pmap.h>
+#include <kern/trap.h>
+#include <kern/monitor.h>
+#include <kern/sched.h>
+#include <kern/cpu.h>
+#include <kern/spinlock.h>
+
+struct Env *envs = NULL;		// All environments
+static struct Env *env_free_list;	// Free environment list
+					// (linked by Env->env_link)
+
+#define ENVGENSHIFT	12		// >= LOGNENV
+
+// Global descriptor table.
+//
+// Set up global descriptor table (GDT) with separate segments for
+// kernel mode and user mode.  Segments serve many purposes on the x86.
+// We don't use any of their memory-mapping capabilities, but we need
+// them to switch privilege levels. 
+//
+// The kernel and user segments are identical except for the DPL.
+// To load the SS register, the CPL must equal the DPL.  Thus,
+// we must duplicate the segments for the user and the kernel.
+//
+// In particular, the last argument to the SEG macro used in the
+// definition of gdt specifies the Descriptor Privilege Level (DPL)
+// of that descriptor: 0 for kernel and 3 for user.
+//
+struct Segdesc gdt[NCPU + 5] =
+{
+	// 0x0 - unused (always faults -- for trapping NULL far pointers)
+	SEG_NULL,
+
+	// 0x8 - kernel code segment
+	[GD_KT >> 3] = SEG(STA_X | STA_R, 0x0, 0xffffffff, 0),
+
+	// 0x10 - kernel data segment
+	[GD_KD >> 3] = SEG(STA_W, 0x0, 0xffffffff, 0),
+
+	// 0x18 - user code segment
+	[GD_UT >> 3] = SEG(STA_X | STA_R, 0x0, 0xffffffff, 3),
+
+	// 0x20 - user data segment
+	[GD_UD >> 3] = SEG(STA_W, 0x0, 0xffffffff, 3),
+
+	// Per-CPU TSS descriptors (starting from GD_TSS0) are initialized
+	// in trap_init_percpu()
+	[GD_TSS0 >> 3] = SEG_NULL
+};
+
+struct Pseudodesc gdt_pd = {
+	sizeof(gdt) - 1, (unsigned long) gdt
+};
+
+//
+// Converts an envid to an env pointer.
+// If checkperm is set, the specified environment must be either the
+// current environment or an immediate child of the current environment.
+//
+// RETURNS
+//   0 on success, -E_BAD_ENV on error.
+//   On success, sets *env_store to the environment.
+//   On error, sets *env_store to NULL.
+//
+int
+envid2env(envid_t envid, struct Env **env_store, bool checkperm)
+{
+	struct Env *e;
+
+	// If envid is zero, return the current environment.
+	if (envid == 0) {
+		*env_store = curenv;
+		return 0;
+	}
+
+	// Look up the Env structure via the index part of the envid,
+	// then check the env_id field in that struct Env
+	// to ensure that the envid is not stale
+	// (i.e., does not refer to a _previous_ environment
+	// that used the same slot in the envs[] array).
+	e = &envs[ENVX(envid)];
+	if (e->env_status == ENV_FREE || e->env_id != envid) {
+		*env_store = 0;
+		return -E_BAD_ENV;
+	}
+
+	// Check that the calling environment has legitimate permission
+	// to manipulate the specified environment.
+	// If checkperm is set, the specified environment
+	// must be either the current environment
+	// or an immediate child of the current environment.
+	if (checkperm && e != curenv && e->env_parent_id != curenv->env_id) {
+		*env_store = 0;
+		return -E_BAD_ENV;
+	}
+
+	*env_store = e;
+	return 0;
+}
+
+// Mark all environments in 'envs' as free, set their env_ids to 0,
+// and insert them into the env_free_list.
+// Make sure the environments are in the free list in the same order
+// they are in the envs array (i.e., so that the first call to
+// env_alloc() returns envs[0]).
+//
+void
+env_init(void)
+{
+	// Set up envs array
+	// LAB 3: Your code here.
+	int i;
+	// 确保最小的env在最前端
+	for (i = NENV-1; i >= 0; --i) {
+		envs[i].env_id = 0;
+	
+		envs[i].env_link = env_free_list;
+		env_free_list = &envs[i];
+	}
+	
+	// Per-CPU part of the initialization
+	env_init_percpu();
+}
+
+// Load GDT and segment descriptors.
+void
+env_init_percpu(void)
+{
+	lgdt(&gdt_pd);
+	// The kernel never uses GS or FS, so we leave those set to
+	// the user data segment.
+	asm volatile("movw %%ax,%%gs" : : "a" (GD_UD|3));
+	asm volatile("movw %%ax,%%fs" : : "a" (GD_UD|3));
+	// The kernel does use ES, DS, and SS.  We'll change between
+	// the kernel and user data segments as needed.
+	asm volatile("movw %%ax,%%es" : : "a" (GD_KD));
+	asm volatile("movw %%ax,%%ds" : : "a" (GD_KD));
+	asm volatile("movw %%ax,%%ss" : : "a" (GD_KD));
+	// Load the kernel text segment into CS.
+	asm volatile("ljmp %0,$1f\n 1:\n" : : "i" (GD_KT));
+	// For good measure, clear the local descriptor table (LDT),
+	// since we don't use it.
+	lldt(0);
+}
+
+//
+// Initialize the kernel virtual memory layout for environment e.
+// Allocate a page directory, set e->env_pgdir accordingly,
+// and initialize the kernel portion of the new environment's address space.
+// Do NOT (yet) map anything into the user portion
+// of the environment's virtual address space.
+//
+// Returns 0 on success, < 0 on error.  Errors include:
+//	-E_NO_MEM if page directory or table could not be allocated.
+//  这里又为每个环境分配一个页目录，有点晕了。
+static int
+env_setup_vm(struct Env *e)
+{
+	int i;
+	struct PageInfo *p = NULL;
+
+	// Allocate a page for the page directory
+	if (!(p = page_alloc(ALLOC_ZERO)))
+		return -E_NO_MEM;
+
+	// Now, set e->env_pgdir and initialize the page directory.
+	//
+	// Hint:
+	//    - The VA space of all envs is identical above UTOP
+	//	(except at UVPT, which we've set below).
+	//	See inc/memlayout.h for permissions and layout.
+	//	Can you use kern_pgdir as a template?  Hint: Yes.
+	//	(Make sure you got the permissions right in Lab 2.)
+	//    - The initial VA below UTOP is empty.
+	//    - You do not need to make any more calls to page_alloc.
+	//    - Note: In general, pp_ref is not maintained for
+	//	physical pages mapped only above UTOP, but env_pgdir
+	//	is an exception -- you need to increment env_pgdir's
+	//	pp_ref for env_free to work correctly.
+	//    - The functions in kern/pmap.h are handy.
+
+	
+	// LAB 3: Your code here.
+	// 申请一个页表存用户环境的页目录
+	
+	e->env_pgdir = page2kva(p);
+	// why ?因为在UTOP之上都是一样的，所以可以直接把kern_pgdir的内容全部拷贝过来
+    
+	memcpy(e->env_pgdir, kern_pgdir, PGSIZE);
+	p->pp_ref++;
+	// UVPT maps the env's own page table read-only.
+	// Permissions: kernel R, user R
+	// 但是唯独UVPT这个地方是不一样的，因为要放的是自己的页表目录
+	e->env_pgdir[PDX(UVPT)] = PADDR(e->env_pgdir) | PTE_P | PTE_U;
+
+	return 0;
+}
+
+//
+// Allocates and initializes a new environment.
+// On success, the new environment is stored in *newenv_store.
+//
+// Returns 0 on success, < 0 on failure.  Errors include:
+//	-E_NO_FREE_ENV if all NENV environments are allocated
+//	-E_NO_MEM on memory exhaustion
+//
+int
+env_alloc(struct Env **newenv_store, envid_t parent_id)
+{
+	int32_t generation;
+	int r;
+	struct Env *e;
+
+	if (!(e = env_free_list))
+		return -E_NO_FREE_ENV;
+
+	// Allocate and set up the page directory for this environment.
+	if ((r = env_setup_vm(e)) < 0)
+		return r;
+
+	// Generate an env_id for this environment.
+	generation = (e->env_id + (1 << ENVGENSHIFT)) & ~(NENV - 1);
+	if (generation <= 0)	// Don't create a negative env_id.
+		generation = 1 << ENVGENSHIFT;
+	e->env_id = generation | (e - envs);
+
+	// Set the basic status variables.
+	e->env_parent_id = parent_id;
+	e->env_type = ENV_TYPE_USER;
+	e->env_status = ENV_RUNNABLE;
+	e->env_runs = 0;
+
+	// Clear out all the saved register state,
+	// to prevent the register values
+	// of a prior environment inhabiting this Env structure
+	// from "leaking" into our new environment.
+	memset(&e->env_tf, 0, sizeof(e->env_tf));
+
+	// Set up appropriate initial values for the segment registers.
+	// GD_UD is the user data segment selector in the GDT, and
+	// GD_UT is the user text segment selector (see inc/memlayout.h).
+	// The low 2 bits of each segment register contains the
+	// Requestor Privilege Level (RPL); 3 means user mode.  When
+	// we switch privilege levels, the hardware does various
+	// checks involving the RPL and the Descriptor Privilege Level
+	// (DPL) stored in the descriptors themselves.
+	e->env_tf.tf_ds = GD_UD | 3;
+	e->env_tf.tf_es = GD_UD | 3;
+	e->env_tf.tf_ss = GD_UD | 3;
+	e->env_tf.tf_esp = USTACKTOP;
+	e->env_tf.tf_cs = GD_UT | 3;
+	// You will set e->env_tf.tf_eip later.
+
+	// Enable interrupts while in user mode.
+	// LAB 4: Your code here.
+
+	// Clear the page fault handler until user installs one.
+	e->env_pgfault_upcall = 0;
+
+	// Also clear the IPC receiving flag.
+	e->env_ipc_recving = 0;
+
+	// commit the allocation
+	env_free_list = e->env_link;
+	*newenv_store = e;
+
+	cprintf("[%08x] new env %08x\n", curenv ? curenv->env_id : 0, e->env_id);
+	return 0;
+}
+
+//
+// Allocate len bytes of physical memory for environment env,
+// and map it at virtual address va in the environment's address space.
+// Does not zero or otherwise initialize the mapped pages in any way.
+// Pages should be writable by user and kernel.
+// Panic if any allocation attempt fails.
+//
+static void
+region_alloc(struct Env *e, void *va, size_t len)
+{
+	// LAB 3: Your code here.
+	// (But only if you need it for load_icode.)
+	//
+	struct PageInfo *pp;
+	size_t i;
+	size_t pgs = ROUNDUP(len, PGSIZE)/PGSIZE;
+	size_t pva = ROUNDDOWN((size_t)va, PGSIZE);
+	
+	
+	for(i=0; i < pgs; i++) {
+		if (!(pp = page_alloc(ALLOC_ZERO))) {
+			int ex = -E_NO_MEM;
+	        panic("region_alloc: %e", ex);
+		}
+		page_insert(e->env_pgdir, pp, (void *)pva, PTE_U|PTE_W|PTE_P);
+		pva += PGSIZE;
+		
+	}
+	// Hint: It is easier to use region_alloc if the caller can pass
+	//   'va' and 'len' values that are not page-aligned.
+	//   You should round va down, and round (va + len) up.
+	//   (Watch out for corner-cases!)
+}
+
+//
+// Set up the initial program binary, stack, and processor flags
+// for a user process.
+// This function is ONLY called during kernel initialization,
+// before running the first user-mode environment.
+//
+// This function loads all loadable segments from the ELF binary image
+// into the environment's user memory, starting at the appropriate
+// virtual addresses indicated in the ELF program header.
+// At the same time it clears to zero any portions of these segments
+// that are marked in the program header as being mapped
+// but not actually present in the ELF file - i.e., the program's bss section.
+//
+// All this is very similar to what our boot loader does, except the boot
+// loader also needs to read the code from disk.  Take a look at
+// boot/main.c to get ideas.
+//
+// Finally, this function maps one page for the program's initial stack.
+//
+// load_icode panics if it encounters problems.
+//  - How might load_icode fail?  What might be wrong with the given input?
+//
+static void
+load_icode(struct Env *e, uint8_t *binary)
+{
+	// Hints:
+	//  Load each program segment into virtual memory
+	//  at the address specified in the ELF segment header.
+	//  You should only load segments with ph->p_type == ELF_PROG_LOAD.
+	//  Each segment's virtual address can be found in ph->p_va
+	//  and its size in memory can be found in ph->p_memsz.
+	//  The ph->p_filesz bytes from the ELF binary, starting at
+	//  'binary + ph->p_offset', should be copied to virtual address
+	//  ph->p_va.  Any remaining memory bytes should be cleared to zero.
+	//  (The ELF header should have ph->p_filesz <= ph->p_memsz.)
+	//  Use functions from the previous lab to allocate and map pages.
+	//
+	//  All page protection bits should be user read/write for now.
+	//  ELF segments are not necessarily page-aligned, but you can
+	//  assume for this function that no two segments will touch
+	//  the same virtual page.
+	//
+	//  You may find a function like region_alloc useful.
+	//
+	//  Loading the segments is much simpler if you can move data
+	//  directly into the virtual addresses stored in the ELF binary.
+	//  So which page directory should be in force during
+	//  this function?
+	//
+	//  You must also do something with the program's entry point,
+	//  to make sure that the environment starts executing there.
+	//  What?  (See env_run() and env_pop_tf() below.)
+
+	// LAB 3: Your code here.
+	// 怎么得到program的ELF地址? 就是bianry
+	struct Proghdr *ph, *eph;
+	struct Elf *elfhdr = (struct Elf *)binary;
+	
+	// is this a valid ELF?
+	if (elfhdr->e_magic != ELF_MAGIC)
+		panic("elf header's magic is not correct\n");
+
+	// 所有程序段 
+	ph = (struct Proghdr *)((uint8_t *)elfhdr + elfhdr->e_phoff);
+	eph = ph + elfhdr->e_phnum;
+	// 转换到用户页目录，用户空间映射
+	lcr3(PADDR(e->env_pgdir));
+	
+	for(; ph < eph; ph++) {
+		
+		if (ph->p_type != ELF_PROG_LOAD)
+			continue;
+		if (ph->p_filesz > ph->p_memsz)
+			panic("file size is great than memmory size\n");
+
+		region_alloc(e, (void *)ph->p_va, ph->p_memsz);
+		memcpy((void *)ph->p_va, binary + ph->p_offset, ph->p_filesz);
+		// clear bss section
+		memset((void *)ph->p_va + ph->p_filesz, 0, (ph->p_memsz - ph->p_filesz));
+			
+	}
+	e->env_tf.tf_eip = elfhdr->e_entry;
+	// Now map one page for the program's initial stack
+	// at virtual address USTACKTOP - PGSIZE.
+	
+	// LAB 3: Your code here.
+	
+	// map the user stack
+	region_alloc(e, (void *)USTACKTOP-PGSIZE, PGSIZE);
+	lcr3(PADDR(kern_pgdir));
+}
+
+//
+// Allocates a new env with env_alloc, loads the named elf
+// binary into it with load_icode, and sets its env_type.
+// This function is ONLY called during kernel initialization,
+// before running the first user-mode environment.
+// The new env's parent ID is set to 0.
+//
+void
+env_create(uint8_t *binary, enum EnvType type)
+{
+	// LAB 3: Your code here.
+	struct Env *newenv;
+	int ret = 0;
+	if ((ret = env_alloc(&newenv, 0)) < 0) {
+		panic("env_create: %e\n", ret);
+	}
+	newenv->env_type = type;
+	load_icode(newenv, binary);
+	
+}
+
+//
+// Frees env e and all memory it uses.
+//
+void
+env_free(struct Env *e)
+{
+	pte_t *pt;
+	uint32_t pdeno, pteno;
+	physaddr_t pa;
+
+	// If freeing the current environment, switch to kern_pgdir
+	// before freeing the page directory, just in case the page
+	// gets reused.
+	if (e == curenv)
+		lcr3(PADDR(kern_pgdir));
+
+	// Note the environment's demise.
+	cprintf("[%08x] free env %08x\n", curenv ? curenv->env_id : 0, e->env_id);
+
+	// Flush all mapped pages in the user portion of the address space
+	static_assert(UTOP % PTSIZE == 0);
+	for (pdeno = 0; pdeno < PDX(UTOP); pdeno++) {
+
+		// only look at mapped page tables
+		if (!(e->env_pgdir[pdeno] & PTE_P))
+			continue;
+
+		// find the pa and va of the page table
+		pa = PTE_ADDR(e->env_pgdir[pdeno]);
+		pt = (pte_t*) KADDR(pa);
+
+		// unmap all PTEs in this page table
+		for (pteno = 0; pteno <= PTX(~0); pteno++) {
+			if (pt[pteno] & PTE_P)
+				page_remove(e->env_pgdir, PGADDR(pdeno, pteno, 0));
+		}
+
+		// free the page table itself
+		e->env_pgdir[pdeno] = 0;
+		page_decref(pa2page(pa));
+	}
+
+	// free the page directory
+	pa = PADDR(e->env_pgdir);
+	e->env_pgdir = 0;
+	page_decref(pa2page(pa));
+
+	// return the environment to the free list
+	e->env_status = ENV_FREE;
+	e->env_link = env_free_list;
+	env_free_list = e;
+}
+
+//
+// Frees environment e.
+// If e was the current env, then runs a new environment (and does not return
+// to the caller).
+//
+void
+env_destroy(struct Env *e)
+{
+	// If e is currently running on other CPUs, we change its state to
+	// ENV_DYING. A zombie environment will be freed the next time
+	// it traps to the kernel.
+	if (e->env_status == ENV_RUNNING && curenv != e) {
+		e->env_status = ENV_DYING;
+		return;
+	}
+
+	env_free(e);
+
+	if (curenv == e) {
+		curenv = NULL;
+		sched_yield();
+	}
+}
+
+
+//
+// Restores the register values in the Trapframe with the 'iret' instruction.
+// This exits the kernel and starts executing some environment's code.
+//
+// This function does not return.
+//
+void
+env_pop_tf(struct Trapframe *tf)
+{
+	// Record the CPU we are running on for user-space debugging
+	curenv->env_cpunum = cpunum();
+
+	asm volatile(
+		"\tmovl %0,%%esp\n"
+		"\tpopal\n"
+		"\tpopl %%es\n"
+		"\tpopl %%ds\n"
+		"\taddl $0x8,%%esp\n" /* skip tf_trapno and tf_errcode */
+		"\tiret\n"
+		: : "g" (tf) : "memory");
+	panic("iret failed");  /* mostly to placate the compiler */
+}
+
+//
+// Context switch from curenv to env e.
+// Note: if this is the first call to env_run, curenv is NULL.
+//
+// This function does not return.
+//
+void
+env_run(struct Env *e)
+{
+	// Step 1: If this is a context switch (a new environment is running):
+	//	   1. Set the current environment (if any) back to
+	//	      ENV_RUNNABLE if it is ENV_RUNNING (think about
+	//	      what other states it can be in),
+	//	   2. Set 'curenv' to the new environment,
+	//	   3. Set its status to ENV_RUNNING,
+	//	   4. Update its 'env_runs' counter,
+	//	   5. Use lcr3() to switch to its address space.
+	// Step 2: Use env_pop_tf() to restore the environment's
+	//	   registers and drop into user mode in the
+	//	   environment.
+
+	// Hint: This function loads the new environment's state from
+	//	e->env_tf.  Go back through the code you wrote above
+	//	and make sure you have set the relevant parts of
+	//	e->env_tf to sensible values.
+
+	// LAB 3: Your code here.
+	if (curenv && curenv->env_status == ENV_RUNNING) {
+		curenv->env_status = ENV_RUNNABLE;
+	}
+	curenv = e;
+	curenv->env_status = ENV_RUNNING;
+	curenv->env_runs++;
+	lcr3(PADDR(curenv->env_pgdir));
+	
+	unlock_kernel();
+	// iret退出内核, 回到用户环境执行,
+	// 在load_icode() 中 env_tf保存了可执行文件的eip等信息
+	env_pop_tf(&(curenv->env_tf));
+
+	
+	// panic("env_run not yet implemented");
+}
+

lab/LAB4.si4project/Backup/fork(3728).c

@@ -0,0 +1,90 @@
+// implement fork from user space
+
+#include <inc/string.h>
+#include <inc/lib.h>
+
+// PTE_COW marks copy-on-write page table entries.
+// It is one of the bits explicitly allocated to user processes (PTE_AVAIL).
+#define PTE_COW		0x800
+
+//
+// Custom page fault handler - if faulting page is copy-on-write,
+// map in our own private writable copy.
+//
+static void
+pgfault(struct UTrapframe *utf)
+{
+	void *addr = (void *) utf->utf_fault_va;
+	uint32_t err = utf->utf_err;
+	int r;
+
+	// Check that the faulting access was (1) a write, and (2) to a
+	// copy-on-write page.  If not, panic.
+	// Hint:
+	//   Use the read-only page table mappings at uvpt
+	//   (see <inc/memlayout.h>).
+
+	// LAB 4: Your code here.
+
+	// Allocate a new page, map it at a temporary location (PFTEMP),
+	// copy the data from the old page to the new page, then move the new
+	// page to the old page's address.
+	// Hint:
+	//   You should make three system calls.
+
+	// LAB 4: Your code here.
+
+	panic("pgfault not implemented");
+}
+
+//
+// Map our virtual page pn (address pn*PGSIZE) into the target envid
+// at the same virtual address.  If the page is writable or copy-on-write,
+// the new mapping must be created copy-on-write, and then our mapping must be
+// marked copy-on-write as well.  (Exercise: Why do we need to mark ours
+// copy-on-write again if it was already copy-on-write at the beginning of
+// this function?)
+//
+// Returns: 0 on success, < 0 on error.
+// It is also OK to panic on error.
+//
+static int
+duppage(envid_t envid, unsigned pn)
+{
+	int r;
+
+	// LAB 4: Your code here.
+	panic("duppage not implemented");
+	return 0;
+}
+
+//
+// User-level fork with copy-on-write.
+// Set up our page fault handler appropriately.
+// Create a child.
+// Copy our address space and page fault handler setup to the child.
+// Then mark the child as runnable and return.
+//
+// Returns: child's envid to the parent, 0 to the child, < 0 on error.
+// It is also OK to panic on error.
+//
+// Hint:
+//   Use uvpd, uvpt, and duppage.
+//   Remember to fix "thisenv" in the child process.
+//   Neither user exception stack should ever be marked copy-on-write,
+//   so you must allocate a new page for the child's user exception stack.
+//
+envid_t
+fork(void)
+{
+	// LAB 4: Your code here.
+	panic("fork not implemented");
+}
+
+// Challenge!
+int
+sfork(void)
+{
+	panic("sfork not implemented");
+	return -E_INVAL;
+}

lab/LAB4.si4project/Backup/ipc(963).c

@@ -0,0 +1,56 @@
+// User-level IPC library routines
+
+#include <inc/lib.h>
+
+// Receive a value via IPC and return it.
+// If 'pg' is nonnull, then any page sent by the sender will be mapped at
+//	that address.
+// If 'from_env_store' is nonnull, then store the IPC sender's envid in
+//	*from_env_store.
+// If 'perm_store' is nonnull, then store the IPC sender's page permission
+//	in *perm_store (this is nonzero iff a page was successfully
+//	transferred to 'pg').
+// If the system call fails, then store 0 in *fromenv and *perm (if
+//	they're nonnull) and return the error.
+// Otherwise, return the value sent by the sender
+//
+// Hint:
+//   Use 'thisenv' to discover the value and who sent it.
+//   If 'pg' is null, pass sys_ipc_recv a value that it will understand
+//   as meaning "no page".  (Zero is not the right value, since that's
+//   a perfectly valid place to map a page.)
+int32_t
+ipc_recv(envid_t *from_env_store, void *pg, int *perm_store)
+{
+	// LAB 4: Your code here.
+	panic("ipc_recv not implemented");
+	return 0;
+}
+
+// Send 'val' (and 'pg' with 'perm', if 'pg' is nonnull) to 'toenv'.
+// This function keeps trying until it succeeds.
+// It should panic() on any error other than -E_IPC_NOT_RECV.
+//
+// Hint:
+//   Use sys_yield() to be CPU-friendly.
+//   If 'pg' is null, pass sys_ipc_try_send a value that it will understand
+//   as meaning "no page".  (Zero is not the right value.)
+void
+ipc_send(envid_t to_env, uint32_t val, void *pg, int perm)
+{
+	// LAB 4: Your code here.
+	panic("ipc_send not implemented");
+}
+
+// Find the first environment of the given type.  We'll use this to
+// find special environments.
+// Returns 0 if no such environment exists.
+envid_t
+ipc_find_env(enum EnvType type)
+{
+	int i;
+	for (i = 0; i < NENV; i++)
+		if (envs[i].env_type == type)
+			return envs[i].env_id;
+	return 0;
+}

lab/LAB4.si4project/Backup/pfentry(173).S

@@ -0,0 +1,82 @@
+#include <inc/mmu.h>
+#include <inc/memlayout.h>
+
+// Page fault upcall entrypoint.
+
+// This is where we ask the kernel to redirect us to whenever we cause
+// a page fault in user space (see the call to sys_set_pgfault_handler
+// in pgfault.c).
+//
+// When a page fault actually occurs, the kernel switches our ESP to
+// point to the user exception stack if we're not already on the user
+// exception stack, and then it pushes a UTrapframe onto our user
+// exception stack:
+//
+//	trap-time esp
+//	trap-time eflags
+//	trap-time eip
+//	utf_regs.reg_eax
+//	...
+//	utf_regs.reg_esi
+//	utf_regs.reg_edi
+//	utf_err (error code)
+//	utf_fault_va            <-- %esp
+//
+// If this is a recursive fault, the kernel will reserve for us a
+// blank word above the trap-time esp for scratch work when we unwind
+// the recursive call.
+//
+// We then have call up to the appropriate page fault handler in C
+// code, pointed to by the global variable '_pgfault_handler'.
+
+.text
+.globl _pgfault_upcall
+_pgfault_upcall:
+	// Call the C page fault handler.
+	pushl %esp			// function argument: pointer to UTF
+	movl _pgfault_handler, %eax
+	call *%eax
+	addl $4, %esp			// pop function argument
+	
+	// Now the C page fault handler has returned and you must return
+	// to the trap time state.
+	// Push trap-time %eip onto the trap-time stack.
+	//
+	// Explanation:
+	//   We must prepare the trap-time stack for our eventual return to
+	//   re-execute the instruction that faulted.
+	//   Unfortunately, we can't return directly from the exception stack:
+	//   We can't call 'jmp', since that requires that we load the address
+	//   into a register, and all registers must have their trap-time
+	//   values after the return.
+	//   We can't call 'ret' from the exception stack either, since if we
+	//   did, %esp would have the wrong value.
+	//   So instead, we push the trap-time %eip onto the *trap-time* stack!
+	//   Below we'll switch to that stack and call 'ret', which will
+	//   restore %eip to its pre-fault value.
+	//
+	//   In the case of a recursive fault on the exception stack,
+	//   note that the word we're pushing now will fit in the
+	//   blank word that the kernel reserved for us.
+	//
+	// Throughout the remaining code, think carefully about what
+	// registers are available for intermediate calculations.  You
+	// may find that you have to rearrange your code in non-obvious
+	// ways as registers become unavailable as scratch space.
+	//
+	// LAB 4: Your code here.
+
+	// Restore the trap-time registers.  After you do this, you
+	// can no longer modify any general-purpose registers.
+	// LAB 4: Your code here.
+
+	// Restore eflags from the stack.  After you do this, you can
+	// no longer use arithmetic operations or anything else that
+	// modifies eflags.
+	// LAB 4: Your code here.
+
+	// Switch back to the adjusted trap-time stack.
+	// LAB 4: Your code here.
+
+	// Return to re-execute the instruction that faulted.
+	// LAB 4: Your code here.

lab/LAB4.si4project/Backup/pgfault(4647).c

@@ -0,0 +1,37 @@
+// User-level page fault handler support.
+// Rather than register the C page fault handler directly with the
+// kernel as the page fault handler, we register the assembly language
+// wrapper in pfentry.S, which in turns calls the registered C
+// function.
+
+#include <inc/lib.h>
+
+
+// Assembly language pgfault entrypoint defined in lib/pfentry.S.
+extern void _pgfault_upcall(void);
+
+// Pointer to currently installed C-language pgfault handler.
+void (*_pgfault_handler)(struct UTrapframe *utf);
+
+//
+// Set the page fault handler function.
+// If there isn't one yet, _pgfault_handler will be 0.
+// The first time we register a handler, we need to
+// allocate an exception stack (one page of memory with its top
+// at UXSTACKTOP), and tell the kernel to call the assembly-language
+// _pgfault_upcall routine when a page fault occurs.
+//
+void
+set_pgfault_handler(void (*handler)(struct UTrapframe *utf))
+{
+	int r;
+
+	if (_pgfault_handler == 0) {
+		// First time through!
+		// LAB 4: Your code here.
+		panic("set_pgfault_handler not implemented");
+	}
+
+	// Save handler pointer for assembly to call.
+	_pgfault_handler = handler;
+}

lab/LAB4.si4project/Backup/picirq(7101).c

@@ -0,0 +1,86 @@
+/* See COPYRIGHT for copyright information. */
+
+#include <inc/assert.h>
+#include <inc/trap.h>
+
+#include <kern/picirq.h>
+
+
+// Current IRQ mask.
+// Initial IRQ mask has interrupt 2 enabled (for slave 8259A).
+uint16_t irq_mask_8259A = 0xFFFF & ~(1<<IRQ_SLAVE);
+static bool didinit;
+
+/* Initialize the 8259A interrupt controllers. */
+void
+pic_init(void)
+{
+	didinit = 1;
+
+	// mask all interrupts
+	outb(IO_PIC1+1, 0xFF);
+	outb(IO_PIC2+1, 0xFF);
+
+	// Set up master (8259A-1)
+
+	// ICW1:  0001g0hi
+	//    g:  0 = edge triggering, 1 = level triggering
+	//    h:  0 = cascaded PICs, 1 = master only
+	//    i:  0 = no ICW4, 1 = ICW4 required
+	outb(IO_PIC1, 0x11);
+
+	// ICW2:  Vector offset
+	outb(IO_PIC1+1, IRQ_OFFSET);
+
+	// ICW3:  bit mask of IR lines connected to slave PICs (master PIC),
+	//        3-bit No of IR line at which slave connects to master(slave PIC).
+	outb(IO_PIC1+1, 1<<IRQ_SLAVE);
+
+	// ICW4:  000nbmap
+	//    n:  1 = special fully nested mode
+	//    b:  1 = buffered mode
+	//    m:  0 = slave PIC, 1 = master PIC
+	//	  (ignored when b is 0, as the master/slave role
+	//	  can be hardwired).
+	//    a:  1 = Automatic EOI mode
+	//    p:  0 = MCS-80/85 mode, 1 = intel x86 mode
+	outb(IO_PIC1+1, 0x3);
+
+	// Set up slave (8259A-2)
+	outb(IO_PIC2, 0x11);			// ICW1
+	outb(IO_PIC2+1, IRQ_OFFSET + 8);	// ICW2
+	outb(IO_PIC2+1, IRQ_SLAVE);		// ICW3
+	// NB Automatic EOI mode doesn't tend to work on the slave.
+	// Linux source code says it's "to be investigated".
+	outb(IO_PIC2+1, 0x01);			// ICW4
+
+	// OCW3:  0ef01prs
+	//   ef:  0x = NOP, 10 = clear specific mask, 11 = set specific mask
+	//    p:  0 = no polling, 1 = polling mode
+	//   rs:  0x = NOP, 10 = read IRR, 11 = read ISR
+	outb(IO_PIC1, 0x68);             /* clear specific mask */
+	outb(IO_PIC1, 0x0a);             /* read IRR by default */
+
+	outb(IO_PIC2, 0x68);               /* OCW3 */
+	outb(IO_PIC2, 0x0a);               /* OCW3 */
+
+	if (irq_mask_8259A != 0xFFFF)
+		irq_setmask_8259A(irq_mask_8259A);
+}
+
+void
+irq_setmask_8259A(uint16_t mask)
+{
+	int i;
+	irq_mask_8259A = mask;
+	if (!didinit)
+		return;
+	outb(IO_PIC1+1, (char)mask);
+	outb(IO_PIC2+1, (char)(mask >> 8));
+	cprintf("enabled interrupts:");
+	for (i = 0; i < 16; i++)
+		if (~mask & (1<<i))
+			cprintf(" %d", i);
+	cprintf("\n");
+}
+

lab/LAB4.si4project/Backup/sched(4329).c

@@ -0,0 +1,84 @@
+#include <inc/assert.h>
+#include <inc/x86.h>
+#include <kern/spinlock.h>
+#include <kern/env.h>
+#include <kern/pmap.h>
+#include <kern/monitor.h>
+
+void sched_halt(void);
+
+// Choose a user environment to run and run it.
+void
+sched_yield(void)
+{
+	struct Env *idle;
+
+	// Implement simple round-robin scheduling.
+	//
+	// Search through 'envs' for an ENV_RUNNABLE environment in
+	// circular fashion starting just after the env this CPU was
+	// last running.  Switch to the first such environment found.
+	//
+	// If no envs are runnable, but the environment previously
+	// running on this CPU is still ENV_RUNNING, it's okay to
+	// choose that environment.
+	//
+	// Never choose an environment that's currently running on
+	// another CPU (env_status == ENV_RUNNING). If there are
+	// no runnable environments, simply drop through to the code
+	// below to halt the cpu.
+
+	// LAB 4: Your code here.
+
+	// sched_halt never returns
+	sched_halt();
+}
+
+// Halt this CPU when there is nothing to do. Wait until the
+// timer interrupt wakes it up. This function never returns.
+//
+void
+sched_halt(void)
+{
+	int i;
+
+	// For debugging and testing purposes, if there are no runnable
+	// environments in the system, then drop into the kernel monitor.
+	for (i = 0; i < NENV; i++) {
+		if ((envs[i].env_status == ENV_RUNNABLE ||
+		     envs[i].env_status == ENV_RUNNING ||
+		     envs[i].env_status == ENV_DYING))
+			break;
+	}
+	if (i == NENV) {
+		cprintf("No runnable environments in the system!\n");
+		while (1)
+			monitor(NULL);
+	}
+
+	// Mark that no environment is running on this CPU
+	curenv = NULL;
+	lcr3(PADDR(kern_pgdir));
+
+	// Mark that this CPU is in the HALT state, so that when
+	// timer interupts come in, we know we should re-acquire the
+	// big kernel lock
+	xchg(&thiscpu->cpu_status, CPU_HALTED);
+
+	// Release the big kernel lock as if we were "leaving" the kernel
+	unlock_kernel();
+
+	// Reset stack pointer, enable interrupts and then halt.
+	asm volatile (
+		"movl $0, %%ebp\n"
+		"movl %0, %%esp\n"
+		"pushl $0\n"
+		"pushl $0\n"
+		// Uncomment the following line after completing exercise 13
+		//"sti\n"
+		"1:\n"
+		"hlt\n"
+		"jmp 1b\n"
+	: : "a" (thiscpu->cpu_ts.ts_esp0));
+}
+

lab/LAB4.si4project/Backup/sched(5719).c

@@ -0,0 +1,99 @@
+#include <inc/assert.h>
+#include <inc/x86.h>
+#include <kern/spinlock.h>
+#include <kern/env.h>
+#include <kern/pmap.h>
+#include <kern/monitor.h>
+
+void sched_halt(void);
+
+// Choose a user environment to run and run it.
+void
+sched_yield(void)
+{
+	struct Env *idle;
+
+	// Implement simple round-robin scheduling.
+	//
+	// Search through 'envs' for an ENV_RUNNABLE environment in
+	// circular fashion starting just after the env this CPU was
+	// last running.  Switch to the first such environment found.
+	//
+	// If no envs are runnable, but the environment previously
+	// running on this CPU is still ENV_RUNNING, it's okay to
+	// choose that environment.
+	//
+	// Never choose an environment that's currently running on
+	// another CPU (env_status == ENV_RUNNING). If there are
+	// no runnable environments, simply drop through to the code
+	// below to halt the cpu.
+
+	// LAB 4: Your code here.
+	
+	idle = curenv;
+	int start_envid = idle ? ENVX(idle->env_id)+1 : 0;
+
+	for (int i = 0; i < NENV; i++) {
+		int j = (start_envid + i) % NENV;
+		if (envs[j].env_status == ENV_RUNNABLE) {
+			env_run(&envs[j]);
+		}
+	}
+
+	if (idle && idle->env_status == ENV_RUNNING) {
+		env_run(idle);
+	}
+
+	// sched_halt never returns
+	sched_halt();
+
+}
+
+// Halt this CPU when there is nothing to do. Wait until the
+// timer interrupt wakes it up. This function never returns.
+//
+void
+sched_halt(void)
+{
+	int i;
+
+	// For debugging and testing purposes, if there are no runnable
+	// environments in the system, then drop into the kernel monitor.
+	for (i = 0; i < NENV; i++) {
+		if ((envs[i].env_status == ENV_RUNNABLE ||
+		     envs[i].env_status == ENV_RUNNING ||
+		     envs[i].env_status == ENV_DYING))
+			break;
+	}
+	if (i == NENV) {
+		cprintf("No runnable environments in the system!\n");
+		while (1)
+			monitor(NULL);
+	}
+
+	// Mark that no environment is running on this CPU
+	curenv = NULL;
+	lcr3(PADDR(kern_pgdir));
+
+	// Mark that this CPU is in the HALT state, so that when
+	// timer interupts come in, we know we should re-acquire the
+	// big kernel lock
+	xchg(&thiscpu->cpu_status, CPU_HALTED);
+
+	// Release the big kernel lock as if we were "leaving" the kernel
+	unlock_kernel();
+
+	// Reset stack pointer, enable interrupts and then halt.
+	asm volatile (
+		"movl $0, %%ebp\n"
+		"movl %0, %%esp\n"
+		"pushl $0\n"
+		"pushl $0\n"
+		// Uncomment the following line after completing exercise 13
+		//"sti\n"
+		"1:\n"
+		"hlt\n"
+		"jmp 1b\n"
+	: : "a" (thiscpu->cpu_ts.ts_esp0));
+}
+

lab/LAB4.si4project/Backup/sched(6307).c

@@ -0,0 +1,99 @@
+#include <inc/assert.h>
+#include <inc/x86.h>
+#include <kern/spinlock.h>
+#include <kern/env.h>
+#include <kern/pmap.h>
+#include <kern/monitor.h>
+
+void sched_halt(void);
+
+// Choose a user environment to run and run it.
+void
+sched_yield(void)
+{
+	struct Env *idle;
+
+	// Implement simple round-robin scheduling.
+	//
+	// Search through 'envs' for an ENV_RUNNABLE environment in
+	// circular fashion starting just after the env this CPU was
+	// last running.  Switch to the first such environment found.
+	//
+	// If no envs are runnable, but the environment previously
+	// running on this CPU is still ENV_RUNNING, it's okay to
+	// choose that environment.
+	//
+	// Never choose an environment that's currently running on
+	// another CPU (env_status == ENV_RUNNING). If there are
+	// no runnable environments, simply drop through to the code
+	// below to halt the cpu.
+
+	// LAB 4: Your code here.
+	
+	idle = curenv;
+	int start_envid = idle ? ENVX(idle->env_id)+1 : 0;
+
+	for (int i = 0; i < NENV; i++) {
+		int j = (start_envid + i) % NENV;
+		if (envs[j].env_status == ENV_RUNNABLE) {
+			env_run(&envs[j]);
+		}
+	}
+
+	if (idle && idle->env_status == ENV_RUNNING) {
+		env_run(idle);
+	}
+
+	// sched_halt never returns
+	sched_halt();
+
+}
+
+// Halt this CPU when there is nothing to do. Wait until the
+// timer interrupt wakes it up. This function never returns.
+//
+void
+sched_halt(void)
+{
+	int i;
+
+	// For debugging and testing purposes, if there are no runnable
+	// environments in the system, then drop into the kernel monitor.
+	for (i = 0; i < NENV; i++) {
+		if ((envs[i].env_status == ENV_RUNNABLE ||
+		     envs[i].env_status == ENV_RUNNING ||
+		     envs[i].env_status == ENV_DYING))
+			break;
+	}
+	if (i == NENV) {
+		cprintf("No runnable environments in the system!\n");
+		while (1)
+			monitor(NULL);
+	}
+
+	// Mark that no environment is running on this CPU
+	curenv = NULL;
+	lcr3(PADDR(kern_pgdir));
+
+	// Mark that this CPU is in the HALT state, so that when
+	// timer interupts come in, we know we should re-acquire the
+	// big kernel lock
+	xchg(&thiscpu->cpu_status, CPU_HALTED);
+
+	// Release the big kernel lock as if we were "leaving" the kernel
+	unlock_kernel();
+
+	// Reset stack pointer, enable interrupts and then halt.
+	asm volatile (
+		"movl $0, %%ebp\n"
+		"movl %0, %%esp\n"
+		"pushl $0\n"
+		"pushl $0\n"
+		// Uncomment the following line after completing exercise 13
+		//"sti\n"
+		"1:\n"
+		"hlt\n"
+		"jmp 1b\n"
+	: : "a" (thiscpu->cpu_ts.ts_esp0));
+}
+

lab/LAB4.si4project/Backup/syscall(1135).c

@@ -0,0 +1,378 @@
+/* See COPYRIGHT for copyright information. */
+
+#include <inc/x86.h>
+#include <inc/error.h>
+#include <inc/string.h>
+#include <inc/assert.h>
+
+#include <kern/env.h>
+#include <kern/pmap.h>
+#include <kern/trap.h>
+#include <kern/syscall.h>
+#include <kern/console.h>
+#include <kern/sched.h>
+
+// Print a string to the system console.
+// The string is exactly 'len' characters long.
+// Destroys the environment on memory errors.
+static void
+sys_cputs(const char *s, size_t len)
+{
+	// Check that the user has permission to read memory [s, s+len).
+	// Destroy the environment if not.
+
+	// LAB 3: Your code here.
+	user_mem_assert(curenv, (const void *) s, len, 0);
+	// Print the string supplied by the user.
+	cprintf("%.*s", len, s);
+}
+
+// Read a character from the system console without blocking.
+// Returns the character, or 0 if there is no input waiting.
+static int
+sys_cgetc(void)
+{
+	return cons_getc();
+}
+
+// Returns the current environment's envid.
+static envid_t
+sys_getenvid(void)
+{
+	return curenv->env_id;
+}
+
+// Destroy a given environment (possibly the currently running environment).
+//
+// Returns 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+static int
+sys_env_destroy(envid_t envid)
+{
+	int r;
+	struct Env *e;
+
+	if ((r = envid2env(envid, &e, 1)) < 0)
+		return r;
+	if (e == curenv)
+		cprintf("[%08x] exiting gracefully\n", curenv->env_id);
+	else
+		cprintf("[%08x] destroying %08x\n", curenv->env_id, e->env_id);
+	env_destroy(e);
+	return 0;
+}
+
+// Deschedule current environment and pick a different one to run.
+static void
+sys_yield(void)
+{
+	sched_yield();
+}
+
+
+// Allocate a new environment.
+// Returns envid of new environment, or < 0 on error.  Errors are:
+//	-E_NO_FREE_ENV if no free environment is available.
+//	-E_NO_MEM on memory exhaustion.
+static envid_t
+sys_exofork(void)
+{
+	// Create the new environment with env_alloc(), from kern/env.c.
+	// It should be left as env_alloc created it, except that
+	// status is set to ENV_NOT_RUNNABLE, and the register set is copied
+	// from the current environment -- but tweaked so sys_exofork
+	// will appear to return 0.
+	// LAB 4: Your code here.
+	struct Env *newenv;
+	int32_t ret;
+	if ((ret = env_alloc(&newenv, sys_getenvid())) < 0) {
+		// 两个函数的返回值是一样的
+		return ret;
+	}
+	newenv->env_status = ENV_NOT_RUNNABLE;
+	newenv->env_tf = curenv->env_tf;
+	// newenv的返回值为0, 实现子进程返回0值
+	newenv->env_tf.tf_regs.reg_eax = 0;
+	// 返回值存放在eax中
+	return newenv->env_id;
+	
+	// panic("sys_exofork not implemented");
+}
+
+// Set envid's env_status to status, which must be ENV_RUNNABLE
+// or ENV_NOT_RUNNABLE.
+//
+// Returns 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+//	-E_INVAL if status is not a valid status for an environment.
+static int
+sys_env_set_status(envid_t envid, int status)
+{
+	// Hint: Use the 'envid2env' function from kern/env.c to translate an
+	// envid to a struct Env.
+	// You should set envid2env's third argument to 1, which will
+	// check whether the current environment has permission to set
+	// envid's status.
+
+	// LAB 4: Your code here.
+	struct Env *e;
+	if (envid2env(envid, &e, 1)) return -E_BAD_ENV;
+
+	if (status != ENV_NOT_RUNNABLE && status != ENV_RUNNABLE) 
+		return -E_INVAL;
+
+	e->env_status = status;
+	return 0;
+}
+
+// Set the page fault upcall for 'envid' by modifying the corresponding struct
+// Env's 'env_pgfault_upcall' field.  When 'envid' causes a page fault, the
+// kernel will push a fault record onto the exception stack, then branch to
+// 'func'.
+//
+// Returns 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+static int
+sys_env_set_pgfault_upcall(envid_t envid, void *func)
+{
+	// LAB 4: Your code here.
+
+	
+	panic("sys_env_set_pgfault_upcall not implemented");
+}
+
+// Allocate a page of memory and map it at 'va' with permission
+// 'perm' in the address space of 'envid'.
+// The page's contents are set to 0.
+// If a page is already mapped at 'va', that page is unmapped as a
+// side effect.
+//
+// perm -- PTE_U | PTE_P must be set, PTE_AVAIL | PTE_W may or may not be set,
+//         but no other bits may be set.  See PTE_SYSCALL in inc/mmu.h.
+//
+// Return 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+//	-E_INVAL if va >= UTOP, or va is not page-aligned.
+//	-E_INVAL if perm is inappropriate (see above).
+//	-E_NO_MEM if there's no memory to allocate the new page,
+//		or to allocate any necessary page tables.
+static int
+sys_page_alloc(envid_t envid, void *va, int perm)
+{
+	// Hint: This function is a wrapper around page_alloc() and
+	//   page_insert() from kern/pmap.c.
+	//   Most of the new code you write should be to check the
+	//   parameters for correctness.
+	//   If page_insert() fails, remember to free the page you
+	//   allocated!
+	
+	// LAB 4: Your code here.
+	int ret = 0;
+	struct Env *env;
+	
+	if ((ret = envid2env(envid, &env, 1)) < 0) 
+		return -E_BAD_ENV;
+	
+	if((uintptr_t)va >= UTOP || PGOFF(va))
+		return -E_INVAL;
+	if ((perm & PTE_U) == 0 || (perm & PTE_P) == 0)
+        return -E_INVAL;
+	if (perm & ~PTE_SYSCALL)
+		return -E_INVAL;
+	
+	struct PageInfo *pp = page_alloc(ALLOC_ZERO);
+	if(!pp) 
+		return -E_NO_MEM;
+	
+	if (page_insert(env->env_pgdir, pp, va, perm) < 0)
+		return -E_NO_MEM;
+
+	return 0;
+	// panic("sys_page_alloc not implemented");
+}
+
+// Map the page of memory at 'srcva' in srcenvid's address space
+// at 'dstva' in dstenvid's address space with permission 'perm'.
+// Perm has the same restrictions as in sys_page_alloc, except
+// that it also must not grant write access to a read-only
+// page.
+//
+// Return 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if srcenvid and/or dstenvid doesn't currently exist,
+//		or the caller doesn't have permission to change one of them.
+//	-E_INVAL if srcva >= UTOP or srcva is not page-aligned,
+//		or dstva >= UTOP or dstva is not page-aligned.
+//	-E_INVAL is srcva is not mapped in srcenvid's address space.
+//	-E_INVAL if perm is inappropriate (see sys_page_alloc).
+//	-E_INVAL if (perm & PTE_W), but srcva is read-only in srcenvid's
+//		address space.
+//	-E_NO_MEM if there's no memory to allocate any necessary page tables.
+static int
+sys_page_map(envid_t srcenvid, void *srcva,
+	     envid_t dstenvid, void *dstva, int perm)
+{
+	// Hint: This function is a wrapper around page_lookup() and
+	//   page_insert() from kern/pmap.c.
+	//   Again, most of the new code you write should be to check the
+	//   parameters for correctness.
+	//   Use the third argument to page_lookup() to
+	//   check the current permissions on the page.
+
+	// LAB 4: Your code here.
+	int ret = 0;
+	struct Env *srcenv, *dstenv;
+	struct PageInfo *srcpp, *dstpp;
+	pte_t *pte;
+	if ((envid2env(srcenvid, &srcenv, 1) < 0 )|| ( envid2env(dstenvid, &dstenv, 1) < 0)) 
+		return -E_BAD_ENV;
+	if ((uintptr_t)srcva >= UTOP || PGOFF(srcva) || (uintptr_t)dstva >= UTOP || PGOFF(dstva))
+        return -E_INVAL;
+	if ( (perm & PTE_U) == 0 || (perm & PTE_P) == 0 || (perm & ~PTE_SYSCALL))
+		return -E_INVAL;
+	if (!(srcpp = page_lookup(srcenv->env_pgdir, srcva, &pte)))
+		return -E_INVAL;
+	if ((perm & PTE_W) && ((*pte & PTE_W) == 0))
+        return -E_INVAL;
+	if (page_insert(dstenv->env_pgdir, srcpp, dstva, perm) < 0)
+        return -E_NO_MEM;
+
+	return 0;
+	// panic("sys_page_map not implemented");
+}
+
+// Unmap the page of memory at 'va' in the address space of 'envid'.
+// If no page is mapped, the function silently succeeds.
+//
+// Return 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+//	-E_INVAL if va >= UTOP, or va is not page-aligned.
+static int
+sys_page_unmap(envid_t envid, void *va)
+{
+	// Hint: This function is a wrapper around page_remove().
+
+	// LAB 4: Your code here.
+	int ret = 0;
+	struct Env *env;
+	
+	if ((ret = envid2env(envid, &env, 1)) < 0) 
+		return -E_BAD_ENV;
+	if ((uintptr_t)va >= UTOP || PGOFF(va))
+        return -E_INVAL;
+	page_remove(env->env_pgdir, va);
+	return 0;
+	// panic("sys_page_unmap not implemented");
+}
+
+// Try to send 'value' to the target env 'envid'.
+// If srcva < UTOP, then also send page currently mapped at 'srcva',
+// so that receiver gets a duplicate mapping of the same page.
+//
+// The send fails with a return value of -E_IPC_NOT_RECV if the
+// target is not blocked, waiting for an IPC.
+//
+// The send also can fail for the other reasons listed below.
+//
+// Otherwise, the send succeeds, and the target's ipc fields are
+// updated as follows:
+//    env_ipc_recving is set to 0 to block future sends;
+//    env_ipc_from is set to the sending envid;
+//    env_ipc_value is set to the 'value' parameter;
+//    env_ipc_perm is set to 'perm' if a page was transferred, 0 otherwise.
+// The target environment is marked runnable again, returning 0
+// from the paused sys_ipc_recv system call.  (Hint: does the
+// sys_ipc_recv function ever actually return?)
+//
+// If the sender wants to send a page but the receiver isn't asking for one,
+// then no page mapping is transferred, but no error occurs.
+// The ipc only happens when no errors occur.
+//
+// Returns 0 on success, < 0 on error.
+// Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist.
+//		(No need to check permissions.)
+//	-E_IPC_NOT_RECV if envid is not currently blocked in sys_ipc_recv,
+//		or another environment managed to send first.
+//	-E_INVAL if srcva < UTOP but srcva is not page-aligned.
+//	-E_INVAL if srcva < UTOP and perm is inappropriate
+//		(see sys_page_alloc).
+//	-E_INVAL if srcva < UTOP but srcva is not mapped in the caller's
+//		address space.
+//	-E_INVAL if (perm & PTE_W), but srcva is read-only in the
+//		current environment's address space.
+//	-E_NO_MEM if there's not enough memory to map srcva in envid's
+//		address space.
+static int
+sys_ipc_try_send(envid_t envid, uint32_t value, void *srcva, unsigned perm)
+{
+	// LAB 4: Your code here.
+	panic("sys_ipc_try_send not implemented");
+}
+
+// Block until a value is ready.  Record that you want to receive
+// using the env_ipc_recving and env_ipc_dstva fields of struct Env,
+// mark yourself not runnable, and then give up the CPU.
+//
+// If 'dstva' is < UTOP, then you are willing to receive a page of data.
+// 'dstva' is the virtual address at which the sent page should be mapped.
+//
+// This function only returns on error, but the system call will eventually
+// return 0 on success.
+// Return < 0 on error.  Errors are:
+//	-E_INVAL if dstva < UTOP but dstva is not page-aligned.
+static int
+sys_ipc_recv(void *dstva)
+{
+	// LAB 4: Your code here.
+	panic("sys_ipc_recv not implemented");
+	return 0;
+}
+
+// Dispatches to the correct kernel function, passing the arguments.
+int32_t
+syscall(uint32_t syscallno, uint32_t a1, uint32_t a2, uint32_t a3, uint32_t a4, uint32_t a5)
+{
+	// Call the function corresponding to the 'syscallno' parameter.
+	// Return any appropriate return value.
+	// LAB 3: Your code here.
+	switch (syscallno) {
+	case SYS_cputs:
+		sys_cputs((const char*)a1, a2);
+		break;
+	case SYS_cgetc:
+		return sys_cgetc();
+	case SYS_getenvid:
+		ret = sys_getenvid();
+		break;
+	case SYS_env_destroy:
+		return sys_env_destroy(a1);
+	case SYS_yield: 
+		sys_yield();
+		break;
+	case SYS_page_alloc:
+		return sys_page_alloc((envid_t)a1, (void * )a2, (int )a3);
+	
+	case SYS_page_map:
+		return sys_page_map((envid_t) a1, (void *) a2, (envid_t) a3, (void *) a4, (int) a5);
+		
+	case SYS_page_unmap:
+		return sys_page_unmap((envid_t) a1, (void *) a2);
+
+	case SYS_exofork:
+		return sys_exofork();
+
+	case SYS_env_set_status:
+		return sys_env_set_status((envid_t) a1, (int) a2);
+	case NSYSCALLS:
+		return -E_INVAL;
+	
+	default:
+		return -E_INVAL;
+	}
+}
+

lab/LAB4.si4project/Backup/syscall(1286).c

@@ -0,0 +1,383 @@
+/* See COPYRIGHT for copyright information. */
+
+#include <inc/x86.h>
+#include <inc/error.h>
+#include <inc/string.h>
+#include <inc/assert.h>
+
+#include <kern/env.h>
+#include <kern/pmap.h>
+#include <kern/trap.h>
+#include <kern/syscall.h>
+#include <kern/console.h>
+#include <kern/sched.h>
+
+// Print a string to the system console.
+// The string is exactly 'len' characters long.
+// Destroys the environment on memory errors.
+static void
+sys_cputs(const char *s, size_t len)
+{
+	// Check that the user has permission to read memory [s, s+len).
+	// Destroy the environment if not.
+
+	// LAB 3: Your code here.
+	user_mem_assert(curenv, (const void *) s, len, 0);
+	// Print the string supplied by the user.
+	cprintf("%.*s", len, s);
+}
+
+// Read a character from the system console without blocking.
+// Returns the character, or 0 if there is no input waiting.
+static int
+sys_cgetc(void)
+{
+	return cons_getc();
+}
+
+// Returns the current environment's envid.
+static envid_t
+sys_getenvid(void)
+{
+	return curenv->env_id;
+}
+
+// Destroy a given environment (possibly the currently running environment).
+//
+// Returns 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+static int
+sys_env_destroy(envid_t envid)
+{
+	int r;
+	struct Env *e;
+
+	if ((r = envid2env(envid, &e, 1)) < 0)
+		return r;
+	if (e == curenv)
+		cprintf("[%08x] exiting gracefully\n", curenv->env_id);
+	else
+		cprintf("[%08x] destroying %08x\n", curenv->env_id, e->env_id);
+	env_destroy(e);
+	return 0;
+}
+
+// Deschedule current environment and pick a different one to run.
+static void
+sys_yield(void)
+{
+	sched_yield();
+}
+
+
+// Allocate a new environment.
+// Returns envid of new environment, or < 0 on error.  Errors are:
+//	-E_NO_FREE_ENV if no free environment is available.
+//	-E_NO_MEM on memory exhaustion.
+static envid_t
+sys_exofork(void)
+{
+	// Create the new environment with env_alloc(), from kern/env.c.
+	// It should be left as env_alloc created it, except that
+	// status is set to ENV_NOT_RUNNABLE, and the register set is copied
+	// from the current environment -- but tweaked so sys_exofork
+	// will appear to return 0.
+	// LAB 4: Your code here.
+	struct Env *newenv;
+	int32_t ret;
+	if ((ret = env_alloc(&newenv, sys_getenvid())) < 0) {
+		// 两个函数的返回值是一样的
+		return ret;
+	}
+	newenv->env_status = ENV_NOT_RUNNABLE;
+	newenv->env_tf = curenv->env_tf;
+	// newenv的返回值为0, 实现子进程返回0值
+	newenv->env_tf.tf_regs.reg_eax = 0;
+	// 返回值存放在eax中
+	return newenv->env_id;
+	
+	// panic("sys_exofork not implemented");
+}
+
+// Set envid's env_status to status, which must be ENV_RUNNABLE
+// or ENV_NOT_RUNNABLE.
+//
+// Returns 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+//	-E_INVAL if status is not a valid status for an environment.
+static int
+sys_env_set_status(envid_t envid, int status)
+{
+	// Hint: Use the 'envid2env' function from kern/env.c to translate an
+	// envid to a struct Env.
+	// You should set envid2env's third argument to 1, which will
+	// check whether the current environment has permission to set
+	// envid's status.
+
+	// LAB 4: Your code here.
+	struct Env *e;
+	if (envid2env(envid, &e, 1)) return -E_BAD_ENV;
+
+	if (status != ENV_NOT_RUNNABLE && status != ENV_RUNNABLE) 
+		return -E_INVAL;
+
+	e->env_status = status;
+	return 0;
+}
+
+// Set the page fault upcall for 'envid' by modifying the corresponding struct
+// Env's 'env_pgfault_upcall' field.  When 'envid' causes a page fault, the
+// kernel will push a fault record onto the exception stack, then branch to
+// 'func'.
+//
+// Returns 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+static int
+sys_env_set_pgfault_upcall(envid_t envid, void *func)
+{
+	// LAB 4: Your code here.
+	struct Env *e;
+	if (envid2env(envid, &e, 1)) 
+		return -E_BAD_ENV;
+
+	e->env_pgfault_upcall = func;
+	return 0;
+	// panic("sys_env_set_pgfault_upcall not implemented");
+}
+
+// Allocate a page of memory and map it at 'va' with permission
+// 'perm' in the address space of 'envid'.
+// The page's contents are set to 0.
+// If a page is already mapped at 'va', that page is unmapped as a
+// side effect.
+//
+// perm -- PTE_U | PTE_P must be set, PTE_AVAIL | PTE_W may or may not be set,
+//         but no other bits may be set.  See PTE_SYSCALL in inc/mmu.h.
+//
+// Return 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+//	-E_INVAL if va >= UTOP, or va is not page-aligned.
+//	-E_INVAL if perm is inappropriate (see above).
+//	-E_NO_MEM if there's no memory to allocate the new page,
+//		or to allocate any necessary page tables.
+static int
+sys_page_alloc(envid_t envid, void *va, int perm)
+{
+	// Hint: This function is a wrapper around page_alloc() and
+	//   page_insert() from kern/pmap.c.
+	//   Most of the new code you write should be to check the
+	//   parameters for correctness.
+	//   If page_insert() fails, remember to free the page you
+	//   allocated!
+	
+	// LAB 4: Your code here.
+	int ret = 0;
+	struct Env *env;
+	
+	if ((ret = envid2env(envid, &env, 1)) < 0) 
+		return -E_BAD_ENV;
+	
+	if((uintptr_t)va >= UTOP || PGOFF(va))
+		return -E_INVAL;
+	if ((perm & PTE_U) == 0 || (perm & PTE_P) == 0)
+        return -E_INVAL;
+	if (perm & ~PTE_SYSCALL)
+		return -E_INVAL;
+	
+	struct PageInfo *pp = page_alloc(ALLOC_ZERO);
+	if(!pp) 
+		return -E_NO_MEM;
+	
+	if (page_insert(env->env_pgdir, pp, va, perm) < 0)
+		return -E_NO_MEM;
+
+	return 0;
+	// panic("sys_page_alloc not implemented");
+}
+
+// Map the page of memory at 'srcva' in srcenvid's address space
+// at 'dstva' in dstenvid's address space with permission 'perm'.
+// Perm has the same restrictions as in sys_page_alloc, except
+// that it also must not grant write access to a read-only
+// page.
+//
+// Return 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if srcenvid and/or dstenvid doesn't currently exist,
+//		or the caller doesn't have permission to change one of them.
+//	-E_INVAL if srcva >= UTOP or srcva is not page-aligned,
+//		or dstva >= UTOP or dstva is not page-aligned.
+//	-E_INVAL is srcva is not mapped in srcenvid's address space.
+//	-E_INVAL if perm is inappropriate (see sys_page_alloc).
+//	-E_INVAL if (perm & PTE_W), but srcva is read-only in srcenvid's
+//		address space.
+//	-E_NO_MEM if there's no memory to allocate any necessary page tables.
+static int
+sys_page_map(envid_t srcenvid, void *srcva,
+	     envid_t dstenvid, void *dstva, int perm)
+{
+	// Hint: This function is a wrapper around page_lookup() and
+	//   page_insert() from kern/pmap.c.
+	//   Again, most of the new code you write should be to check the
+	//   parameters for correctness.
+	//   Use the third argument to page_lookup() to
+	//   check the current permissions on the page.
+
+	// LAB 4: Your code here.
+	int ret = 0;
+	struct Env *srcenv, *dstenv;
+	struct PageInfo *srcpp, *dstpp;
+	pte_t *pte;
+	if ((envid2env(srcenvid, &srcenv, 1) < 0 )|| ( envid2env(dstenvid, &dstenv, 1) < 0)) 
+		return -E_BAD_ENV;
+	if ((uintptr_t)srcva >= UTOP || PGOFF(srcva) || (uintptr_t)dstva >= UTOP || PGOFF(dstva))
+        return -E_INVAL;
+	if ( (perm & PTE_U) == 0 || (perm & PTE_P) == 0 || (perm & ~PTE_SYSCALL))
+		return -E_INVAL;
+	if (!(srcpp = page_lookup(srcenv->env_pgdir, srcva, &pte)))
+		return -E_INVAL;
+	if ((perm & PTE_W) && ((*pte & PTE_W) == 0))
+        return -E_INVAL;
+	if (page_insert(dstenv->env_pgdir, srcpp, dstva, perm) < 0)
+        return -E_NO_MEM;
+
+	return 0;
+	// panic("sys_page_map not implemented");
+}
+
+// Unmap the page of memory at 'va' in the address space of 'envid'.
+// If no page is mapped, the function silently succeeds.
+//
+// Return 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+//	-E_INVAL if va >= UTOP, or va is not page-aligned.
+static int
+sys_page_unmap(envid_t envid, void *va)
+{
+	// Hint: This function is a wrapper around page_remove().
+
+	// LAB 4: Your code here.
+	int ret = 0;
+	struct Env *env;
+	
+	if ((ret = envid2env(envid, &env, 1)) < 0) 
+		return -E_BAD_ENV;
+	if ((uintptr_t)va >= UTOP || PGOFF(va))
+        return -E_INVAL;
+	page_remove(env->env_pgdir, va);
+	return 0;
+	// panic("sys_page_unmap not implemented");
+}
+
+// Try to send 'value' to the target env 'envid'.
+// If srcva < UTOP, then also send page currently mapped at 'srcva',
+// so that receiver gets a duplicate mapping of the same page.
+//
+// The send fails with a return value of -E_IPC_NOT_RECV if the
+// target is not blocked, waiting for an IPC.
+//
+// The send also can fail for the other reasons listed below.
+//
+// Otherwise, the send succeeds, and the target's ipc fields are
+// updated as follows:
+//    env_ipc_recving is set to 0 to block future sends;
+//    env_ipc_from is set to the sending envid;
+//    env_ipc_value is set to the 'value' parameter;
+//    env_ipc_perm is set to 'perm' if a page was transferred, 0 otherwise.
+// The target environment is marked runnable again, returning 0
+// from the paused sys_ipc_recv system call.  (Hint: does the
+// sys_ipc_recv function ever actually return?)
+//
+// If the sender wants to send a page but the receiver isn't asking for one,
+// then no page mapping is transferred, but no error occurs.
+// The ipc only happens when no errors occur.
+//
+// Returns 0 on success, < 0 on error.
+// Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist.
+//		(No need to check permissions.)
+//	-E_IPC_NOT_RECV if envid is not currently blocked in sys_ipc_recv,
+//		or another environment managed to send first.
+//	-E_INVAL if srcva < UTOP but srcva is not page-aligned.
+//	-E_INVAL if srcva < UTOP and perm is inappropriate
+//		(see sys_page_alloc).
+//	-E_INVAL if srcva < UTOP but srcva is not mapped in the caller's
+//		address space.
+//	-E_INVAL if (perm & PTE_W), but srcva is read-only in the
+//		current environment's address space.
+//	-E_NO_MEM if there's not enough memory to map srcva in envid's
+//		address space.
+static int
+sys_ipc_try_send(envid_t envid, uint32_t value, void *srcva, unsigned perm)
+{
+	// LAB 4: Your code here.
+	panic("sys_ipc_try_send not implemented");
+}
+
+// Block until a value is ready.  Record that you want to receive
+// using the env_ipc_recving and env_ipc_dstva fields of struct Env,
+// mark yourself not runnable, and then give up the CPU.
+//
+// If 'dstva' is < UTOP, then you are willing to receive a page of data.
+// 'dstva' is the virtual address at which the sent page should be mapped.
+//
+// This function only returns on error, but the system call will eventually
+// return 0 on success.
+// Return < 0 on error.  Errors are:
+//	-E_INVAL if dstva < UTOP but dstva is not page-aligned.
+static int
+sys_ipc_recv(void *dstva)
+{
+	// LAB 4: Your code here.
+	panic("sys_ipc_recv not implemented");
+	return 0;
+}
+
+// Dispatches to the correct kernel function, passing the arguments.
+int32_t
+syscall(uint32_t syscallno, uint32_t a1, uint32_t a2, uint32_t a3, uint32_t a4, uint32_t a5)
+{
+	// Call the function corresponding to the 'syscallno' parameter.
+	// Return any appropriate return value.
+	// LAB 3: Your code here.
+	switch (syscallno) {
+	case SYS_cputs:
+		sys_cputs((const char*)a1, a2);
+		break;
+	case SYS_cgetc:
+		return sys_cgetc();
+	case SYS_getenvid:
+		return  sys_getenvid();
+	case SYS_env_destroy:
+		return sys_env_destroy(a1);
+	case SYS_yield: 
+		sys_yield();
+		break;
+	case SYS_page_alloc:
+		return sys_page_alloc((envid_t)a1, (void * )a2, (int )a3);
+	case SYS_env_set_pgfault_upcall:
+		return sys_env_set_pgfault_upcall((envid_t) a1, (void *) a2);
+	case SYS_page_map:
+		return sys_page_map((envid_t) a1, (void *) a2, (envid_t) a3, (void *) a4, (int) a5);
+		
+	case SYS_page_unmap:
+		return sys_page_unmap((envid_t) a1, (void *) a2);
+
+	case SYS_exofork:
+		return sys_exofork();
+
+	case SYS_env_set_status:
+		return sys_env_set_status((envid_t) a1, (int) a2);
+	case NSYSCALLS:
+		return -E_INVAL;
+	
+	default:
+		return -E_INVAL;
+	}
+	return 0;
+}
+

lab/LAB4.si4project/Backup/syscall(2799).c

@@ -0,0 +1,301 @@
+/* See COPYRIGHT for copyright information. */
+
+#include <inc/x86.h>
+#include <inc/error.h>
+#include <inc/string.h>
+#include <inc/assert.h>
+
+#include <kern/env.h>
+#include <kern/pmap.h>
+#include <kern/trap.h>
+#include <kern/syscall.h>
+#include <kern/console.h>
+#include <kern/sched.h>
+
+// Print a string to the system console.
+// The string is exactly 'len' characters long.
+// Destroys the environment on memory errors.
+static void
+sys_cputs(const char *s, size_t len)
+{
+	// Check that the user has permission to read memory [s, s+len).
+	// Destroy the environment if not.
+
+	// LAB 3: Your code here.
+	user_mem_assert(curenv, (const void *) s, len, 0);
+	// Print the string supplied by the user.
+	cprintf("%.*s", len, s);
+}
+
+// Read a character from the system console without blocking.
+// Returns the character, or 0 if there is no input waiting.
+static int
+sys_cgetc(void)
+{
+	return cons_getc();
+}
+
+// Returns the current environment's envid.
+static envid_t
+sys_getenvid(void)
+{
+	return curenv->env_id;
+}
+
+// Destroy a given environment (possibly the currently running environment).
+//
+// Returns 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+static int
+sys_env_destroy(envid_t envid)
+{
+	int r;
+	struct Env *e;
+
+	if ((r = envid2env(envid, &e, 1)) < 0)
+		return r;
+	if (e == curenv)
+		cprintf("[%08x] exiting gracefully\n", curenv->env_id);
+	else
+		cprintf("[%08x] destroying %08x\n", curenv->env_id, e->env_id);
+	env_destroy(e);
+	return 0;
+}
+
+// Deschedule current environment and pick a different one to run.
+static void
+sys_yield(void)
+{
+	sched_yield();
+}
+
+// Allocate a new environment.
+// Returns envid of new environment, or < 0 on error.  Errors are:
+//	-E_NO_FREE_ENV if no free environment is available.
+//	-E_NO_MEM on memory exhaustion.
+static envid_t
+sys_exofork(void)
+{
+	// Create the new environment with env_alloc(), from kern/env.c.
+	// It should be left as env_alloc created it, except that
+	// status is set to ENV_NOT_RUNNABLE, and the register set is copied
+	// from the current environment -- but tweaked so sys_exofork
+	// will appear to return 0.
+
+	// LAB 4: Your code here.
+	panic("sys_exofork not implemented");
+}
+
+// Set envid's env_status to status, which must be ENV_RUNNABLE
+// or ENV_NOT_RUNNABLE.
+//
+// Returns 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+//	-E_INVAL if status is not a valid status for an environment.
+static int
+sys_env_set_status(envid_t envid, int status)
+{
+	// Hint: Use the 'envid2env' function from kern/env.c to translate an
+	// envid to a struct Env.
+	// You should set envid2env's third argument to 1, which will
+	// check whether the current environment has permission to set
+	// envid's status.
+
+	// LAB 4: Your code here.
+	panic("sys_env_set_status not implemented");
+}
+
+// Set the page fault upcall for 'envid' by modifying the corresponding struct
+// Env's 'env_pgfault_upcall' field.  When 'envid' causes a page fault, the
+// kernel will push a fault record onto the exception stack, then branch to
+// 'func'.
+//
+// Returns 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+static int
+sys_env_set_pgfault_upcall(envid_t envid, void *func)
+{
+	// LAB 4: Your code here.
+	panic("sys_env_set_pgfault_upcall not implemented");
+}
+
+// Allocate a page of memory and map it at 'va' with permission
+// 'perm' in the address space of 'envid'.
+// The page's contents are set to 0.
+// If a page is already mapped at 'va', that page is unmapped as a
+// side effect.
+//
+// perm -- PTE_U | PTE_P must be set, PTE_AVAIL | PTE_W may or may not be set,
+//         but no other bits may be set.  See PTE_SYSCALL in inc/mmu.h.
+//
+// Return 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+//	-E_INVAL if va >= UTOP, or va is not page-aligned.
+//	-E_INVAL if perm is inappropriate (see above).
+//	-E_NO_MEM if there's no memory to allocate the new page,
+//		or to allocate any necessary page tables.
+static int
+sys_page_alloc(envid_t envid, void *va, int perm)
+{
+	// Hint: This function is a wrapper around page_alloc() and
+	//   page_insert() from kern/pmap.c.
+	//   Most of the new code you write should be to check the
+	//   parameters for correctness.
+	//   If page_insert() fails, remember to free the page you
+	//   allocated!
+
+	// LAB 4: Your code here.
+	panic("sys_page_alloc not implemented");
+}
+
+// Map the page of memory at 'srcva' in srcenvid's address space
+// at 'dstva' in dstenvid's address space with permission 'perm'.
+// Perm has the same restrictions as in sys_page_alloc, except
+// that it also must not grant write access to a read-only
+// page.
+//
+// Return 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if srcenvid and/or dstenvid doesn't currently exist,
+//		or the caller doesn't have permission to change one of them.
+//	-E_INVAL if srcva >= UTOP or srcva is not page-aligned,
+//		or dstva >= UTOP or dstva is not page-aligned.
+//	-E_INVAL is srcva is not mapped in srcenvid's address space.
+//	-E_INVAL if perm is inappropriate (see sys_page_alloc).
+//	-E_INVAL if (perm & PTE_W), but srcva is read-only in srcenvid's
+//		address space.
+//	-E_NO_MEM if there's no memory to allocate any necessary page tables.
+static int
+sys_page_map(envid_t srcenvid, void *srcva,
+	     envid_t dstenvid, void *dstva, int perm)
+{
+	// Hint: This function is a wrapper around page_lookup() and
+	//   page_insert() from kern/pmap.c.
+	//   Again, most of the new code you write should be to check the
+	//   parameters for correctness.
+	//   Use the third argument to page_lookup() to
+	//   check the current permissions on the page.
+
+	// LAB 4: Your code here.
+	panic("sys_page_map not implemented");
+}
+
+// Unmap the page of memory at 'va' in the address space of 'envid'.
+// If no page is mapped, the function silently succeeds.
+//
+// Return 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+//	-E_INVAL if va >= UTOP, or va is not page-aligned.
+static int
+sys_page_unmap(envid_t envid, void *va)
+{
+	// Hint: This function is a wrapper around page_remove().
+
+	// LAB 4: Your code here.
+	panic("sys_page_unmap not implemented");
+}
+
+// Try to send 'value' to the target env 'envid'.
+// If srcva < UTOP, then also send page currently mapped at 'srcva',
+// so that receiver gets a duplicate mapping of the same page.
+//
+// The send fails with a return value of -E_IPC_NOT_RECV if the
+// target is not blocked, waiting for an IPC.
+//
+// The send also can fail for the other reasons listed below.
+//
+// Otherwise, the send succeeds, and the target's ipc fields are
+// updated as follows:
+//    env_ipc_recving is set to 0 to block future sends;
+//    env_ipc_from is set to the sending envid;
+//    env_ipc_value is set to the 'value' parameter;
+//    env_ipc_perm is set to 'perm' if a page was transferred, 0 otherwise.
+// The target environment is marked runnable again, returning 0
+// from the paused sys_ipc_recv system call.  (Hint: does the
+// sys_ipc_recv function ever actually return?)
+//
+// If the sender wants to send a page but the receiver isn't asking for one,
+// then no page mapping is transferred, but no error occurs.
+// The ipc only happens when no errors occur.
+//
+// Returns 0 on success, < 0 on error.
+// Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist.
+//		(No need to check permissions.)
+//	-E_IPC_NOT_RECV if envid is not currently blocked in sys_ipc_recv,
+//		or another environment managed to send first.
+//	-E_INVAL if srcva < UTOP but srcva is not page-aligned.
+//	-E_INVAL if srcva < UTOP and perm is inappropriate
+//		(see sys_page_alloc).
+//	-E_INVAL if srcva < UTOP but srcva is not mapped in the caller's
+//		address space.
+//	-E_INVAL if (perm & PTE_W), but srcva is read-only in the
+//		current environment's address space.
+//	-E_NO_MEM if there's not enough memory to map srcva in envid's
+//		address space.
+static int
+sys_ipc_try_send(envid_t envid, uint32_t value, void *srcva, unsigned perm)
+{
+	// LAB 4: Your code here.
+	panic("sys_ipc_try_send not implemented");
+}
+
+// Block until a value is ready.  Record that you want to receive
+// using the env_ipc_recving and env_ipc_dstva fields of struct Env,
+// mark yourself not runnable, and then give up the CPU.
+//
+// If 'dstva' is < UTOP, then you are willing to receive a page of data.
+// 'dstva' is the virtual address at which the sent page should be mapped.
+//
+// This function only returns on error, but the system call will eventually
+// return 0 on success.
+// Return < 0 on error.  Errors are:
+//	-E_INVAL if dstva < UTOP but dstva is not page-aligned.
+static int
+sys_ipc_recv(void *dstva)
+{
+	// LAB 4: Your code here.
+	panic("sys_ipc_recv not implemented");
+	return 0;
+}
+
+// Dispatches to the correct kernel function, passing the arguments.
+int32_t
+syscall(uint32_t syscallno, uint32_t a1, uint32_t a2, uint32_t a3, uint32_t a4, uint32_t a5)
+{
+	// Call the function corresponding to the 'syscallno' parameter.
+	// Return any appropriate return value.
+	// LAB 3: Your code here.
+	
+	
+	// panic("syscall not implemented");
+
+	int ret = 0;
+	switch (syscallno) {
+	case SYS_cputs:
+		sys_cputs((const char*)a1, a2);
+		break;
+	case SYS_cgetc:
+		ret = sys_cgetc();
+		
+		break;
+	case SYS_getenvid:
+		ret = sys_getenvid();
+		break;
+	case SYS_env_destroy:
+		sys_env_destroy(a1);
+		break;
+	case NSYSCALLS:
+		return -E_INVAL;
+		
+	default:
+		return -E_INVAL;
+	}
+
+	return ret;
+}
+

lab/LAB4.si4project/Backup/syscall(5045).h

@@ -0,0 +1,22 @@
+#ifndef JOS_INC_SYSCALL_H
+#define JOS_INC_SYSCALL_H
+
+/* system call numbers */
+enum {
+	SYS_cputs = 0,
+	SYS_cgetc,
+	SYS_getenvid,
+	SYS_env_destroy,
+	SYS_page_alloc,
+	SYS_page_map,
+	SYS_page_unmap,
+	SYS_exofork,
+	SYS_env_set_status,
+	SYS_env_set_pgfault_upcall,
+	SYS_yield,
+	SYS_ipc_try_send,
+	SYS_ipc_recv,
+	NSYSCALLS
+};
+
+#endif /* !JOS_INC_SYSCALL_H */

lab/LAB4.si4project/Backup/syscall(7459).c

@@ -0,0 +1,384 @@
+/* See COPYRIGHT for copyright information. */
+
+#include <inc/x86.h>
+#include <inc/error.h>
+#include <inc/string.h>
+#include <inc/assert.h>
+
+#include <kern/env.h>
+#include <kern/pmap.h>
+#include <kern/trap.h>
+#include <kern/syscall.h>
+#include <kern/console.h>
+#include <kern/sched.h>
+
+// Print a string to the system console.
+// The string is exactly 'len' characters long.
+// Destroys the environment on memory errors.
+static void
+sys_cputs(const char *s, size_t len)
+{
+	// Check that the user has permission to read memory [s, s+len).
+	// Destroy the environment if not.
+
+	// LAB 3: Your code here.
+	user_mem_assert(curenv, (const void *) s, len, 0);
+	// Print the string supplied by the user.
+	cprintf("%.*s", len, s);
+}
+
+// Read a character from the system console without blocking.
+// Returns the character, or 0 if there is no input waiting.
+static int
+sys_cgetc(void)
+{
+	return cons_getc();
+}
+
+// Returns the current environment's envid.
+static envid_t
+sys_getenvid(void)
+{
+	return curenv->env_id;
+}
+
+// Destroy a given environment (possibly the currently running environment).
+//
+// Returns 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+static int
+sys_env_destroy(envid_t envid)
+{
+	int r;
+	struct Env *e;
+
+	if ((r = envid2env(envid, &e, 1)) < 0)
+		return r;
+	if (e == curenv)
+		cprintf("[%08x] exiting gracefully\n", curenv->env_id);
+	else
+		cprintf("[%08x] destroying %08x\n", curenv->env_id, e->env_id);
+	env_destroy(e);
+	return 0;
+}
+
+// Deschedule current environment and pick a different one to run.
+static void
+sys_yield(void)
+{
+	sched_yield();
+}
+
+
+// Allocate a new environment.
+// Returns envid of new environment, or < 0 on error.  Errors are:
+//	-E_NO_FREE_ENV if no free environment is available.
+//	-E_NO_MEM on memory exhaustion.
+static envid_t
+sys_exofork(void)
+{
+	// Create the new environment with env_alloc(), from kern/env.c.
+	// It should be left as env_alloc created it, except that
+	// status is set to ENV_NOT_RUNNABLE, and the register set is copied
+	// from the current environment -- but tweaked so sys_exofork
+	// will appear to return 0.
+	// LAB 4: Your code here.
+	struct Env *newenv;
+	int32_t ret;
+	if ((ret = env_alloc(&newenv, sys_getenvid())) < 0) {
+		// 两个函数的返回值是一样的
+		return ret;
+	}
+	newenv->env_status = ENV_NOT_RUNNABLE;
+	newenv->env_tf = curenv->env_tf;
+	// newenv的返回值为0, 实现子进程返回0值
+	newenv->env_tf.tf_regs.reg_eax = 0;
+	
+	// 返回值存放在eax中
+	return newenv->env_id;
+	
+	// panic("sys_exofork not implemented");
+}
+
+// Set envid's env_status to status, which must be ENV_RUNNABLE
+// or ENV_NOT_RUNNABLE.
+//
+// Returns 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+//	-E_INVAL if status is not a valid status for an environment.
+static int
+sys_env_set_status(envid_t envid, int status)
+{
+	// Hint: Use the 'envid2env' function from kern/env.c to translate an
+	// envid to a struct Env.
+	// You should set envid2env's third argument to 1, which will
+	// check whether the current environment has permission to set
+	// envid's status.
+
+	// LAB 4: Your code here.
+	struct Env *e;
+	if (envid2env(envid, &e, 1)) return -E_BAD_ENV;
+
+	if (status != ENV_NOT_RUNNABLE && status != ENV_RUNNABLE) 
+		return -E_INVAL;
+
+	e->env_status = status;
+	return 0;
+}
+
+// Set the page fault upcall for 'envid' by modifying the corresponding struct
+// Env's 'env_pgfault_upcall' field.  When 'envid' causes a page fault, the
+// kernel will push a fault record onto the exception stack, then branch to
+// 'func'.
+//
+// Returns 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+static int
+sys_env_set_pgfault_upcall(envid_t envid, void *func)
+{
+	// LAB 4: Your code here.
+	struct Env *e;
+	if (envid2env(envid, &e, 1)) 
+		return -E_BAD_ENV;
+	// cprintf("set pgfault upcall\n");
+	e->env_pgfault_upcall = func;
+	return 0;
+	// panic("sys_env_set_pgfault_upcall not implemented");
+}
+
+// Allocate a page of memory and map it at 'va' with permission
+// 'perm' in the address space of 'envid'.
+// The page's contents are set to 0.
+// If a page is already mapped at 'va', that page is unmapped as a
+// side effect.
+//
+// perm -- PTE_U | PTE_P must be set, PTE_AVAIL | PTE_W may or may not be set,
+//         but no other bits may be set.  See PTE_SYSCALL in inc/mmu.h.
+//
+// Return 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+//	-E_INVAL if va >= UTOP, or va is not page-aligned.
+//	-E_INVAL if perm is inappropriate (see above).
+//	-E_NO_MEM if there's no memory to allocate the new page,
+//		or to allocate any necessary page tables.
+static int
+sys_page_alloc(envid_t envid, void *va, int perm)
+{
+	// Hint: This function is a wrapper around page_alloc() and
+	//   page_insert() from kern/pmap.c.
+	//   Most of the new code you write should be to check the
+	//   parameters for correctness.
+	//   If page_insert() fails, remember to free the page you
+	//   allocated!
+	
+	// LAB 4: Your code here.
+	int ret = 0;
+	struct Env *env;
+	
+	if ((ret = envid2env(envid, &env, 1)) < 0) 
+		return -E_BAD_ENV;
+	
+	if((uintptr_t)va >= UTOP || PGOFF(va))
+		return -E_INVAL;
+	if ((perm & PTE_U) == 0 || (perm & PTE_P) == 0)
+        return -E_INVAL;
+	if (perm & ~PTE_SYSCALL)
+		return -E_INVAL;
+	
+	struct PageInfo *pp = page_alloc(ALLOC_ZERO);
+	if(!pp) 
+		return -E_NO_MEM;
+	
+	if (page_insert(env->env_pgdir, pp, va, perm) < 0)
+		return -E_NO_MEM;
+
+	return 0;
+	// panic("sys_page_alloc not implemented");
+}
+
+// Map the page of memory at 'srcva' in srcenvid's address space
+// at 'dstva' in dstenvid's address space with permission 'perm'.
+// Perm has the same restrictions as in sys_page_alloc, except
+// that it also must not grant write access to a read-only
+// page.
+//
+// Return 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if srcenvid and/or dstenvid doesn't currently exist,
+//		or the caller doesn't have permission to change one of them.
+//	-E_INVAL if srcva >= UTOP or srcva is not page-aligned,
+//		or dstva >= UTOP or dstva is not page-aligned.
+//	-E_INVAL is srcva is not mapped in srcenvid's address space.
+//	-E_INVAL if perm is inappropriate (see sys_page_alloc).
+//	-E_INVAL if (perm & PTE_W), but srcva is read-only in srcenvid's
+//		address space.
+//	-E_NO_MEM if there's no memory to allocate any necessary page tables.
+static int
+sys_page_map(envid_t srcenvid, void *srcva,
+	     envid_t dstenvid, void *dstva, int perm)
+{
+	// Hint: This function is a wrapper around page_lookup() and
+	//   page_insert() from kern/pmap.c.
+	//   Again, most of the new code you write should be to check the
+	//   parameters for correctness.
+	//   Use the third argument to page_lookup() to
+	//   check the current permissions on the page.
+
+	// LAB 4: Your code here.
+	int ret = 0;
+	struct Env *srcenv, *dstenv;
+	struct PageInfo *srcpp, *dstpp;
+	pte_t *pte;
+	if ((envid2env(srcenvid, &srcenv, 1) < 0 )|| ( envid2env(dstenvid, &dstenv, 1) < 0)) 
+		return -E_BAD_ENV;
+	if ((uintptr_t)srcva >= UTOP || PGOFF(srcva) || (uintptr_t)dstva >= UTOP || PGOFF(dstva))
+        return -E_INVAL;
+	if ( (perm & PTE_U) == 0 || (perm & PTE_P) == 0 || (perm & ~PTE_SYSCALL))
+		return -E_INVAL;
+	if (!(srcpp = page_lookup(srcenv->env_pgdir, srcva, &pte)))
+		return -E_INVAL;
+	if ((perm & PTE_W) && ((*pte & PTE_W) == 0))
+        return -E_INVAL;
+	if (page_insert(dstenv->env_pgdir, srcpp, dstva, perm) < 0)
+        return -E_NO_MEM;
+
+	return 0;
+	// panic("sys_page_map not implemented");
+}
+
+// Unmap the page of memory at 'va' in the address space of 'envid'.
+// If no page is mapped, the function silently succeeds.
+//
+// Return 0 on success, < 0 on error.  Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist,
+//		or the caller doesn't have permission to change envid.
+//	-E_INVAL if va >= UTOP, or va is not page-aligned.
+static int
+sys_page_unmap(envid_t envid, void *va)
+{
+	// Hint: This function is a wrapper around page_remove().
+
+	// LAB 4: Your code here.
+	int ret = 0;
+	struct Env *env;
+	
+	if ((ret = envid2env(envid, &env, 1)) < 0) 
+		return -E_BAD_ENV;
+	if ((uintptr_t)va >= UTOP || PGOFF(va))
+        return -E_INVAL;
+	page_remove(env->env_pgdir, va);
+	return 0;
+	// panic("sys_page_unmap not implemented");
+}
+
+// Try to send 'value' to the target env 'envid'.
+// If srcva < UTOP, then also send page currently mapped at 'srcva',
+// so that receiver gets a duplicate mapping of the same page.
+//
+// The send fails with a return value of -E_IPC_NOT_RECV if the
+// target is not blocked, waiting for an IPC.
+//
+// The send also can fail for the other reasons listed below.
+//
+// Otherwise, the send succeeds, and the target's ipc fields are
+// updated as follows:
+//    env_ipc_recving is set to 0 to block future sends;
+//    env_ipc_from is set to the sending envid;
+//    env_ipc_value is set to the 'value' parameter;
+//    env_ipc_perm is set to 'perm' if a page was transferred, 0 otherwise.
+// The target environment is marked runnable again, returning 0
+// from the paused sys_ipc_recv system call.  (Hint: does the
+// sys_ipc_recv function ever actually return?)
+//
+// If the sender wants to send a page but the receiver isn't asking for one,
+// then no page mapping is transferred, but no error occurs.
+// The ipc only happens when no errors occur.
+//
+// Returns 0 on success, < 0 on error.
+// Errors are:
+//	-E_BAD_ENV if environment envid doesn't currently exist.
+//		(No need to check permissions.)
+//	-E_IPC_NOT_RECV if envid is not currently blocked in sys_ipc_recv,
+//		or another environment managed to send first.
+//	-E_INVAL if srcva < UTOP but srcva is not page-aligned.
+//	-E_INVAL if srcva < UTOP and perm is inappropriate
+//		(see sys_page_alloc).
+//	-E_INVAL if srcva < UTOP but srcva is not mapped in the caller's
+//		address space.
+//	-E_INVAL if (perm & PTE_W), but srcva is read-only in the
+//		current environment's address space.
+//	-E_NO_MEM if there's not enough memory to map srcva in envid's
+//		address space.
+static int
+sys_ipc_try_send(envid_t envid, uint32_t value, void *srcva, unsigned perm)
+{
+	// LAB 4: Your code here.
+	panic("sys_ipc_try_send not implemented");
+}
+
+// Block until a value is ready.  Record that you want to receive
+// using the env_ipc_recving and env_ipc_dstva fields of struct Env,
+// mark yourself not runnable, and then give up the CPU.
+//
+// If 'dstva' is < UTOP, then you are willing to receive a page of data.
+// 'dstva' is the virtual address at which the sent page should be mapped.
+//
+// This function only returns on error, but the system call will eventually
+// return 0 on success.
+// Return < 0 on error.  Errors are:
+//	-E_INVAL if dstva < UTOP but dstva is not page-aligned.
+static int
+sys_ipc_recv(void *dstva)
+{
+	// LAB 4: Your code here.
+	panic("sys_ipc_recv not implemented");
+	return 0;
+}
+
+// Dispatches to the correct kernel function, passing the arguments.
+int32_t
+syscall(uint32_t syscallno, uint32_t a1, uint32_t a2, uint32_t a3, uint32_t a4, uint32_t a5)
+{
+	// Call the function corresponding to the 'syscallno' parameter.
+	// Return any appropriate return value.
+	// LAB 3: Your code here.
+	switch (syscallno) {
+	case SYS_cputs:
+		sys_cputs((const char*)a1, a2);
+		break;
+	case SYS_cgetc:
+		return sys_cgetc();
+	case SYS_getenvid:
+		return  sys_getenvid();
+	case SYS_env_destroy:
+		return sys_env_destroy(a1);
+	case SYS_yield: 
+		sys_yield();
+		break;
+	case SYS_page_alloc:
+		return sys_page_alloc((envid_t)a1, (void * )a2, (int )a3);
+	case SYS_env_set_pgfault_upcall:
+		return sys_env_set_pgfault_upcall((envid_t) a1, (void *) a2);
+	case SYS_page_map:
+		return sys_page_map((envid_t) a1, (void *) a2, (envid_t) a3, (void *) a4, (int) a5);
+		
+	case SYS_page_unmap:
+		return sys_page_unmap((envid_t) a1, (void *) a2);
+
+	case SYS_exofork:
+		return sys_exofork();
+
+	case SYS_env_set_status:
+		return sys_env_set_status((envid_t) a1, (int) a2);
+	case NSYSCALLS:
+		return -E_INVAL;
+	
+	default:
+		return -E_INVAL;
+	}
+	return 0;
+}
+

lab/LAB4.si4project/Backup/trap(1475).c

@@ -0,0 +1,402 @@
+#include <inc/mmu.h>
+#include <inc/x86.h>
+#include <inc/assert.h>
+
+#include <kern/pmap.h>
+#include <kern/trap.h>
+#include <kern/console.h>
+#include <kern/monitor.h>
+#include <kern/env.h>
+#include <kern/syscall.h>
+#include <kern/sched.h>
+#include <kern/kclock.h>
+#include <kern/picirq.h>
+#include <kern/cpu.h>
+#include <kern/spinlock.h>
+
+static struct Taskstate ts;
+
+/* For debugging, so print_trapframe can distinguish between printing
+ * a saved trapframe and printing the current trapframe and print some
+ * additional information in the latter case.
+ */
+static struct Trapframe *last_tf;
+
+/* Interrupt descriptor table.  (Must be built at run time because
+ * shifted function addresses can't be represented in relocation records.)
+ */
+struct Gatedesc idt[256] = { { 0 } };
+struct Pseudodesc idt_pd = {
+	sizeof(idt) - 1, (uint32_t) idt
+};
+
+
+static const char *trapname(int trapno)
+{
+	static const char * const excnames[] = {
+		"Divide error",
+		"Debug",
+		"Non-Maskable Interrupt",
+		"Breakpoint",
+		"Overflow",
+		"BOUND Range Exceeded",
+		"Invalid Opcode",
+		"Device Not Available",
+		"Double Fault",
+		"Coprocessor Segment Overrun",
+		"Invalid TSS",
+		"Segment Not Present",
+		"Stack Fault",
+		"General Protection",
+		"Page Fault",
+		"(unknown trap)",
+		"x87 FPU Floating-Point Error",
+		"Alignment Check",
+		"Machine-Check",
+		"SIMD Floating-Point Exception"
+	};
+
+	if (trapno < ARRAY_SIZE(excnames))
+		return excnames[trapno];
+	if (trapno == T_SYSCALL)
+		return "System call";
+	if (trapno >= IRQ_OFFSET && trapno < IRQ_OFFSET + 16)
+		return "Hardware Interrupt";
+	return "(unknown trap)";
+}
+
+// You will also need to modify trap_init() to initialize the idt to 
+// point to each of these entry points defined in trapentry.S;
+// the SETGATE macro will be helpful here
+void
+trap_init(void)
+{
+
+	extern struct Segdesc gdt[];
+	void divide_handler();
+	void debug_handler();
+	void nmi_handler();
+	void brkpt_handler();
+	void oflow_handler();
+	void bound_handler();
+	void device_handler();
+	void illop_handler();
+	void tss_handler();
+	void segnp_handler();
+	void stack_handler();
+	void gpflt_handler();
+	void pgflt_handler();
+	void fperr_handler();
+	void align_handler();
+	void mchk_handler();
+	void simderr_handler();
+	void syscall_handler();
+	void dblflt_handler();
+	
+	// LAB 3: Your code here.
+	// GD_KT 全局描述符， kernel text
+	SETGATE(idt[T_DIVIDE], 0, GD_KT, divide_handler, 0);
+	SETGATE(idt[T_DEBUG],  0, GD_KT, debug_handler,  0);
+	SETGATE(idt[T_NMI],    0, GD_KT, nmi_handler,    0);
+	SETGATE(idt[T_BRKPT],  0, GD_KT, brkpt_handler,  3);
+	SETGATE(idt[T_OFLOW],  0, GD_KT, oflow_handler,  0);
+	SETGATE(idt[T_BOUND],  0, GD_KT, bound_handler,  0);
+	SETGATE(idt[T_DEVICE], 0, GD_KT, device_handler, 0);
+	SETGATE(idt[T_ILLOP],  0, GD_KT, illop_handler,  0);
+	SETGATE(idt[T_DBLFLT], 0, GD_KT, dblflt_handler, 0);
+	SETGATE(idt[T_TSS],    0, GD_KT, tss_handler,    0);
+    SETGATE(idt[T_SEGNP],  0, GD_KT, segnp_handler,  0);
+    SETGATE(idt[T_STACK],  0, GD_KT, stack_handler,  0);
+    SETGATE(idt[T_GPFLT],  0, GD_KT, gpflt_handler,  0);
+    SETGATE(idt[T_PGFLT],  0, GD_KT, pgflt_handler,  0);
+    SETGATE(idt[T_FPERR],  0, GD_KT, fperr_handler,  0);
+    SETGATE(idt[T_ALIGN],  0, GD_KT, align_handler,  0);
+    SETGATE(idt[T_MCHK],   0, GD_KT, mchk_handler,   0);
+    SETGATE(idt[T_SIMDERR], 0, GD_KT, simderr_handler, 0);
+    SETGATE(idt[T_SYSCALL], 0, GD_KT, syscall_handler, 3);
+
+	// Per-CPU setup 
+	trap_init_percpu();
+}
+
+// Initialize and load the per-CPU TSS and IDT
+void
+trap_init_percpu(void)
+{
+	// The example code here sets up the Task State Segment (TSS) and
+	// the TSS descriptor for CPU 0. But it is incorrect if we are
+	// running on other CPUs because each CPU has its own kernel stack.
+	// Fix the code so that it works for all CPUs.
+	//
+	// Hints:
+	//   - The macro "thiscpu" always refers to the current CPU's
+	//     struct CpuInfo;
+	//   - The ID of the current CPU is given by cpunum() or
+	//     thiscpu->cpu_id;
+	//   - Use "thiscpu->cpu_ts" as the TSS for the current CPU,
+	//     rather than the global "ts" variable;
+	//   - Use gdt[(GD_TSS0 >> 3) + i] for CPU i's TSS descriptor;
+	//   - You mapped the per-CPU kernel stacks in mem_init_mp()
+	//   - Initialize cpu_ts.ts_iomb to prevent unauthorized environments
+	//     from doing IO (0 is not the correct value!)
+	//
+	// ltr sets a 'busy' flag in the TSS selector, so if you
+	// accidentally load the same TSS on more than one CPU, you'll
+	// get a triple fault.  If you set up an individual CPU's TSS
+	// wrong, you may not get a fault until you try to return from
+	// user space on that CPU.
+	//
+	// LAB 4: Your code here:
+	thiscpu->cpu_ts.ts_esp0 = KSTACKTOP - cpunum() * (KSTKGAP + KSTKSIZE);
+    thiscpu->cpu_ts.ts_ss0 = GD_KD;
+
+    // Initialize the TSS slot of the gdt.
+    gdt[(GD_TSS0 >> 3) + cpunum()] = SEG16(STS_T32A, (uint32_t) (&thiscpu->cpu_ts), sizeof(struct Taskstate) - 1, 0);
+    gdt[(GD_TSS0 >> 3) + cpunum()].sd_s = 0;
+
+    // Load the TSS selector (like other segment selectors, the
+    // bottom three bits are special; we leave them 0)
+    ltr(GD_TSS0 + sizeof(struct Segdesc) * cpunum());
+
+    // Load the IDT
+    lidt(&idt_pd);
+}
+
+void
+print_trapframe(struct Trapframe *tf)
+{
+	cprintf("TRAP frame at %p from CPU %d\n", tf, cpunum());
+	print_regs(&tf->tf_regs);
+	cprintf("  es   0x----%04x\n", tf->tf_es);
+	cprintf("  ds   0x----%04x\n", tf->tf_ds);
+	cprintf("  trap 0x%08x %s\n", tf->tf_trapno, trapname(tf->tf_trapno));
+	// If this trap was a page fault that just happened
+	// (so %cr2 is meaningful), print the faulting linear address.
+	if (tf == last_tf && tf->tf_trapno == T_PGFLT)
+		cprintf("  cr2  0x%08x\n", rcr2());
+	cprintf("  err  0x%08x", tf->tf_err);
+	// For page faults, print decoded fault error code:
+	// U/K=fault occurred in user/kernel mode
+	// W/R=a write/read caused the fault
+	// PR=a protection violation caused the fault (NP=page not present).
+	if (tf->tf_trapno == T_PGFLT)
+		cprintf(" [%s, %s, %s]\n",
+			tf->tf_err & 4 ? "user" : "kernel",
+			tf->tf_err & 2 ? "write" : "read",
+			tf->tf_err & 1 ? "protection" : "not-present");
+	else
+		cprintf("\n");
+	cprintf("  eip  0x%08x\n", tf->tf_eip);
+	cprintf("  cs   0x----%04x\n", tf->tf_cs);
+	cprintf("  flag 0x%08x\n", tf->tf_eflags);
+	if ((tf->tf_cs & 3) != 0) {
+		cprintf("  esp  0x%08x\n", tf->tf_esp);
+		cprintf("  ss   0x----%04x\n", tf->tf_ss);
+	}
+}
+
+void
+print_regs(struct PushRegs *regs)
+{
+	cprintf("  edi  0x%08x\n", regs->reg_edi);
+	cprintf("  esi  0x%08x\n", regs->reg_esi);
+	cprintf("  ebp  0x%08x\n", regs->reg_ebp);
+	cprintf("  oesp 0x%08x\n", regs->reg_oesp);
+	cprintf("  ebx  0x%08x\n", regs->reg_ebx);
+	cprintf("  edx  0x%08x\n", regs->reg_edx);
+	cprintf("  ecx  0x%08x\n", regs->reg_ecx);
+	cprintf("  eax  0x%08x\n", regs->reg_eax);
+}
+
+static void
+trap_dispatch(struct Trapframe *tf)
+{
+	// Handle processor exceptions.
+	// LAB 3: Your code here.
+	switch(tf->tf_trapno) {
+		case T_PGFLT:
+			page_fault_handler(tf);
+			break;
+		case T_BRKPT:
+			monitor(tf);
+			break;
+		case T_SYSCALL:
+			
+			tf->tf_regs.reg_eax = syscall(tf->tf_regs.reg_eax, 
+											tf->tf_regs.reg_edx, 
+											tf->tf_regs.reg_ecx, 
+											tf->tf_regs.reg_ebx, 
+											tf->tf_regs.reg_edi, 
+											tf->tf_regs.reg_esi);
+			break;
+		default: 
+			// Unexpected trap: The user process or the kernel has a bug.
+			print_trapframe(tf);
+			if (tf->tf_cs == GD_KT)
+				panic("unhandled trap in kernel");
+			else {
+				env_destroy(curenv);
+				return;
+			}
+			break;
+
+	}
+	
+	// Handle clock interrupts. Don't forget to acknowledge the
+	// interrupt using lapic_eoi() before calling the scheduler!
+	// LAB 4: Your code here.
+
+	
+}
+
+void
+trap(struct Trapframe *tf)
+{
+	// The environment may have set DF and some versions
+	// of GCC rely on DF being clear
+	asm volatile("cld" ::: "cc");
+
+	// Halt the CPU if some other CPU has called panic()
+	extern char *panicstr;
+	if (panicstr)
+		asm volatile("hlt");
+
+	// Re-acqurie the big kernel lock if we were halted in
+	// sched_yield()
+	if (xchg(&thiscpu->cpu_status, CPU_STARTED) == CPU_HALTED)
+		lock_kernel();
+	// Check that interrupts are disabled.  If this assertion
+	// fails, DO NOT be tempted to fix it by inserting a "cli" in
+	// the interrupt path.
+	assert(!(read_eflags() & FL_IF));
+
+	if ((tf->tf_cs & 3) == 3) {
+		// Trapped from user mode.
+		// Acquire the big kernel lock before doing any
+		// serious kernel work.
+		// LAB 4: Your code here.
+		lock_kernel();
+		assert(curenv);
+		
+		// Garbage collect if current enviroment is a zombie
+		if (curenv->env_status == ENV_DYING) {
+			env_free(curenv);
+			curenv = NULL;
+			sched_yield();
+		}
+
+		// Copy trap frame (which is currently on the stack)
+		// into 'curenv->env_tf', so that running the environment
+		// will restart at the trap point.
+		curenv->env_tf = *tf;
+		// The trapframe on the stack should be ignored from here on.
+		tf = &curenv->env_tf;
+	}
+
+	// Record that tf is the last real trapframe so
+	// print_trapframe can print some additional information.
+	last_tf = tf;
+
+	// Dispatch based on what type of trap occurred
+	trap_dispatch(tf);
+
+	// If we made it to this point, then no other environment was
+	// scheduled, so we should return to the current environment
+	// if doing so makes sense.
+	if (curenv && curenv->env_status == ENV_RUNNING)
+		env_run(curenv);
+	else
+		sched_yield();
+}
+
+
+void
+page_fault_handler(struct Trapframe *tf)
+{
+	uint32_t fault_va;
+
+	// Read processor's CR2 register to find the faulting address
+	fault_va = rcr2();
+
+	// Handle kernel-mode page faults.
+
+	// LAB 3: Your code here.
+
+	// 怎么判断是内核模式， CPL位
+
+	if(tf->tf_cs && 3 == 0) {
+        panic("page_fault in kernel mode, fault address %d\n", fault_va);
+    }
+	
+	// We've already handled kernel-mode exceptions, so if we get here,
+	// the page fault happened in user mode.
+
+
+	// Call the environment's page fault upcall, if one exists.  Set up a
+	// page fault stack frame on the user exception stack (below
+	// UXSTACKTOP), then branch to curenv->env_pgfault_upcall.
+	//
+	// The page fault upcall might cause another page fault, in which case
+	// we branch to the page fault upcall recursively, pushing another
+	// page fault stack frame on top of the user exception stack.
+	//
+	// It is convenient for our code which returns from a page fault
+	// (lib/pfentry.S) to have one word of scratch space at the top of the
+	// trap-time stack; it allows us to more easily restore the eip/esp. In
+	// the non-recursive case, we don't have to worry about this because
+	// the top of the regular user stack is free.  In the recursive case,
+	// this means we have to leave an extra word between the current top of
+	// the exception stack and the new stack frame because the exception
+	// stack _is_ the trap-time stack.
+	//
+	// If there's no page fault upcall, the environment didn't allocate a
+	// page for its exception stack or can't write to it, or the exception
+	// stack overflows, then destroy the environment that caused the fault.
+	// Note that the grade script assumes you will first check for the page
+	// fault upcall and print the "user fault va" message below if there is
+	// none.  The remaining three checks can be combined into a single test.
+	//
+	// Hints:
+	//   user_mem_assert() and env_run() are useful here.
+	//   To change what the user environment runs, modify 'curenv->env_tf'
+	//   (the 'tf' variable points at 'curenv->env_tf').
+
+	// LAB 4: Your code here.
+	struct UTrapframe *utf;
+	// cprintf("I'M in page_fault_handler [%08x] user fault va %08x \n",curenv->env_id, fault_va);
+	if (curenv->env_pgfault_upcall) {
+		
+		if (tf->tf_esp >= UXSTACKTOP-PGSIZE && tf->tf_esp < UXSTACKTOP) {
+			// 异常模式下陷入
+			utf = (struct UTrapframe *)(tf->tf_esp - sizeof(struct UTrapframe) - 4);
+
+		}
+		else {
+			// 非异常模式下陷入
+			utf = (struct UTrapframe *)(UXSTACKTOP - sizeof(struct UTrapframe));	
+		}
+		// 检查异常栈是否溢出
+		user_mem_assert(curenv, (const void *) utf, sizeof(struct UTrapframe), PTE_P|PTE_W);
+			
+		utf->utf_fault_va = fault_va;
+		utf->utf_err      = tf->tf_trapno;
+		utf->utf_regs     = tf->tf_regs;
+		utf->utf_eflags   = tf->tf_eflags;
+		// 保存陷入时现场，用于返回
+		utf->utf_eip      = tf->tf_eip;
+		utf->utf_esp      = tf->tf_esp;
+		// 再次转向执行
+		curenv->env_tf.tf_eip        = (uint32_t) curenv->env_pgfault_upcall;
+		// 异常栈
+		curenv->env_tf.tf_esp        = (uint32_t) utf;
+		env_run(curenv);
+	}
+	else {
+		// Destroy the environment that caused the fault.
+		cprintf("[%08x] user fault va %08x ip %08x\n",
+			curenv->env_id, fault_va, tf->tf_eip);
+		print_trapframe(tf);
+		env_destroy(curenv);
+	}
+}
+

lab/LAB4.si4project/Backup/trap(2812).c

@@ -0,0 +1,375 @@
+#include <inc/mmu.h>
+#include <inc/x86.h>
+#include <inc/assert.h>
+
+#include <kern/pmap.h>
+#include <kern/trap.h>
+#include <kern/console.h>
+#include <kern/monitor.h>
+#include <kern/env.h>
+#include <kern/syscall.h>
+#include <kern/sched.h>
+#include <kern/kclock.h>
+#include <kern/picirq.h>
+#include <kern/cpu.h>
+#include <kern/spinlock.h>
+
+static struct Taskstate ts;
+
+/* For debugging, so print_trapframe can distinguish between printing
+ * a saved trapframe and printing the current trapframe and print some
+ * additional information in the latter case.
+ */
+static struct Trapframe *last_tf;
+
+/* Interrupt descriptor table.  (Must be built at run time because
+ * shifted function addresses can't be represented in relocation records.)
+ */
+struct Gatedesc idt[256] = { { 0 } };
+struct Pseudodesc idt_pd = {
+	sizeof(idt) - 1, (uint32_t) idt
+};
+
+
+static const char *trapname(int trapno)
+{
+	static const char * const excnames[] = {
+		"Divide error",
+		"Debug",
+		"Non-Maskable Interrupt",
+		"Breakpoint",
+		"Overflow",
+		"BOUND Range Exceeded",
+		"Invalid Opcode",
+		"Device Not Available",
+		"Double Fault",
+		"Coprocessor Segment Overrun",
+		"Invalid TSS",
+		"Segment Not Present",
+		"Stack Fault",
+		"General Protection",
+		"Page Fault",
+		"(unknown trap)",
+		"x87 FPU Floating-Point Error",
+		"Alignment Check",
+		"Machine-Check",
+		"SIMD Floating-Point Exception"
+	};
+
+	if (trapno < ARRAY_SIZE(excnames))
+		return excnames[trapno];
+	if (trapno == T_SYSCALL)
+		return "System call";
+	if (trapno >= IRQ_OFFSET && trapno < IRQ_OFFSET + 16)
+		return "Hardware Interrupt";
+	return "(unknown trap)";
+}
+
+// You will also need to modify trap_init() to initialize the idt to 
+// point to each of these entry points defined in trapentry.S;
+// the SETGATE macro will be helpful here
+void
+trap_init(void)
+{
+
+	extern struct Segdesc gdt[];
+	void divide_handler();
+	void debug_handler();
+	void nmi_handler();
+	void brkpt_handler();
+	void oflow_handler();
+	void bound_handler();
+	void device_handler();
+	void illop_handler();
+	void tss_handler();
+	void segnp_handler();
+	void stack_handler();
+	void gpflt_handler();
+	void pgflt_handler();
+	void fperr_handler();
+	void align_handler();
+	void mchk_handler();
+	void simderr_handler();
+	void syscall_handler();
+	void dblflt_handler();
+	
+	// LAB 3: Your code here.
+	// GD_KT 全局描述符， kernel text
+	SETGATE(idt[T_DIVIDE], 0, GD_KT, divide_handler, 0);
+	SETGATE(idt[T_DEBUG],  0, GD_KT, debug_handler,  0);
+	SETGATE(idt[T_NMI],    0, GD_KT, nmi_handler,    0);
+	SETGATE(idt[T_BRKPT],  0, GD_KT, brkpt_handler,  3);
+	SETGATE(idt[T_OFLOW],  0, GD_KT, oflow_handler,  0);
+	SETGATE(idt[T_BOUND],  0, GD_KT, bound_handler,  0);
+	SETGATE(idt[T_DEVICE], 0, GD_KT, device_handler, 0);
+	SETGATE(idt[T_ILLOP],  0, GD_KT, illop_handler,  0);
+	SETGATE(idt[T_DBLFLT], 0, GD_KT, dblflt_handler, 0);
+	SETGATE(idt[T_TSS],    0, GD_KT, tss_handler,    0);
+    SETGATE(idt[T_SEGNP],  0, GD_KT, segnp_handler,  0);
+    SETGATE(idt[T_STACK],  0, GD_KT, stack_handler,  0);
+    SETGATE(idt[T_GPFLT],  0, GD_KT, gpflt_handler,  0);
+    SETGATE(idt[T_PGFLT],  0, GD_KT, pgflt_handler,  0);
+    SETGATE(idt[T_FPERR],  0, GD_KT, fperr_handler,  0);
+    SETGATE(idt[T_ALIGN],  0, GD_KT, align_handler,  0);
+    SETGATE(idt[T_MCHK],   0, GD_KT, mchk_handler,   0);
+    SETGATE(idt[T_SIMDERR], 0, GD_KT, simderr_handler, 0);
+    SETGATE(idt[T_SYSCALL], 0, GD_KT, syscall_handler, 3);
+
+	// Per-CPU setup 
+	trap_init_percpu();
+}
+
+// Initialize and load the per-CPU TSS and IDT
+void
+trap_init_percpu(void)
+{
+	// The example code here sets up the Task State Segment (TSS) and
+	// the TSS descriptor for CPU 0. But it is incorrect if we are
+	// running on other CPUs because each CPU has its own kernel stack.
+	// Fix the code so that it works for all CPUs.
+	//
+	// Hints:
+	//   - The macro "thiscpu" always refers to the current CPU's
+	//     struct CpuInfo;
+	//   - The ID of the current CPU is given by cpunum() or
+	//     thiscpu->cpu_id;
+	//   - Use "thiscpu->cpu_ts" as the TSS for the current CPU,
+	//     rather than the global "ts" variable;
+	//   - Use gdt[(GD_TSS0 >> 3) + i] for CPU i's TSS descriptor;
+	//   - You mapped the per-CPU kernel stacks in mem_init_mp()
+	//   - Initialize cpu_ts.ts_iomb to prevent unauthorized environments
+	//     from doing IO (0 is not the correct value!)
+	//
+	// ltr sets a 'busy' flag in the TSS selector, so if you
+	// accidentally load the same TSS on more than one CPU, you'll
+	// get a triple fault.  If you set up an individual CPU's TSS
+	// wrong, you may not get a fault until you try to return from
+	// user space on that CPU.
+	//
+	// LAB 4: Your code here:
+	thiscpu->cpu_ts.ts_esp0 = KSTACKTOP - cpunum() * (KSTKGAP + KSTKSIZE);
+    thiscpu->cpu_ts.ts_ss0 = GD_KD;
+
+    // Initialize the TSS slot of the gdt.
+    gdt[(GD_TSS0 >> 3) + cpunum()] = SEG16(STS_T32A, (uint32_t) (&thiscpu->cpu_ts), sizeof(struct Taskstate) - 1, 0);
+    gdt[(GD_TSS0 >> 3) + cpunum()].sd_s = 0;
+
+    // Load the TSS selector (like other segment selectors, the
+    // bottom three bits are special; we leave them 0)
+    ltr(GD_TSS0 + sizeof(struct Segdesc) * cpunum());
+
+    // Load the IDT
+    lidt(&idt_pd);
+}
+
+void
+print_trapframe(struct Trapframe *tf)
+{
+	cprintf("TRAP frame at %p from CPU %d\n", tf, cpunum());
+	print_regs(&tf->tf_regs);
+	cprintf("  es   0x----%04x\n", tf->tf_es);
+	cprintf("  ds   0x----%04x\n", tf->tf_ds);
+	cprintf("  trap 0x%08x %s\n", tf->tf_trapno, trapname(tf->tf_trapno));
+	// If this trap was a page fault that just happened
+	// (so %cr2 is meaningful), print the faulting linear address.
+	if (tf == last_tf && tf->tf_trapno == T_PGFLT)
+		cprintf("  cr2  0x%08x\n", rcr2());
+	cprintf("  err  0x%08x", tf->tf_err);
+	// For page faults, print decoded fault error code:
+	// U/K=fault occurred in user/kernel mode
+	// W/R=a write/read caused the fault
+	// PR=a protection violation caused the fault (NP=page not present).
+	if (tf->tf_trapno == T_PGFLT)
+		cprintf(" [%s, %s, %s]\n",
+			tf->tf_err & 4 ? "user" : "kernel",
+			tf->tf_err & 2 ? "write" : "read",
+			tf->tf_err & 1 ? "protection" : "not-present");
+	else
+		cprintf("\n");
+	cprintf("  eip  0x%08x\n", tf->tf_eip);
+	cprintf("  cs   0x----%04x\n", tf->tf_cs);
+	cprintf("  flag 0x%08x\n", tf->tf_eflags);
+	if ((tf->tf_cs & 3) != 0) {
+		cprintf("  esp  0x%08x\n", tf->tf_esp);
+		cprintf("  ss   0x----%04x\n", tf->tf_ss);
+	}
+}
+
+void
+print_regs(struct PushRegs *regs)
+{
+	cprintf("  edi  0x%08x\n", regs->reg_edi);
+	cprintf("  esi  0x%08x\n", regs->reg_esi);
+	cprintf("  ebp  0x%08x\n", regs->reg_ebp);
+	cprintf("  oesp 0x%08x\n", regs->reg_oesp);
+	cprintf("  ebx  0x%08x\n", regs->reg_ebx);
+	cprintf("  edx  0x%08x\n", regs->reg_edx);
+	cprintf("  ecx  0x%08x\n", regs->reg_ecx);
+	cprintf("  eax  0x%08x\n", regs->reg_eax);
+}
+
+static void
+trap_dispatch(struct Trapframe *tf)
+{
+	// Handle processor exceptions.
+	// LAB 3: Your code here.
+	switch(tf->tf_trapno) {
+		case T_PGFLT:
+			page_fault_handler(tf);
+			break;
+		case T_BRKPT:
+			monitor(tf);
+			break;
+		case T_SYSCALL:
+			
+			tf->tf_regs.reg_eax = syscall(tf->tf_regs.reg_eax, 
+											tf->tf_regs.reg_edx, 
+											tf->tf_regs.reg_ecx, 
+											tf->tf_regs.reg_ebx, 
+											tf->tf_regs.reg_edi, 
+											tf->tf_regs.reg_esi);
+			break;
+		default: 
+			// Unexpected trap: The user process or the kernel has a bug.
+			print_trapframe(tf);
+			if (tf->tf_cs == GD_KT)
+				panic("unhandled trap in kernel");
+			else {
+				env_destroy(curenv);
+				return;
+			}
+			break;
+
+	}
+	
+	// Handle clock interrupts. Don't forget to acknowledge the
+	// interrupt using lapic_eoi() before calling the scheduler!
+	// LAB 4: Your code here.
+
+	
+}
+
+void
+trap(struct Trapframe *tf)
+{
+	// The environment may have set DF and some versions
+	// of GCC rely on DF being clear
+	asm volatile("cld" ::: "cc");
+
+	// Halt the CPU if some other CPU has called panic()
+	extern char *panicstr;
+	if (panicstr)
+		asm volatile("hlt");
+
+	// Re-acqurie the big kernel lock if we were halted in
+	// sched_yield()
+	if (xchg(&thiscpu->cpu_status, CPU_STARTED) == CPU_HALTED)
+		lock_kernel();
+	// Check that interrupts are disabled.  If this assertion
+	// fails, DO NOT be tempted to fix it by inserting a "cli" in
+	// the interrupt path.
+	assert(!(read_eflags() & FL_IF));
+
+	if ((tf->tf_cs & 3) == 3) {
+		// Trapped from user mode.
+		// Acquire the big kernel lock before doing any
+		// serious kernel work.
+		// LAB 4: Your code here.
+		lock_kernel();
+		assert(curenv);
+		
+		// Garbage collect if current enviroment is a zombie
+		if (curenv->env_status == ENV_DYING) {
+			env_free(curenv);
+			curenv = NULL;
+			sched_yield();
+		}
+
+		// Copy trap frame (which is currently on the stack)
+		// into 'curenv->env_tf', so that running the environment
+		// will restart at the trap point.
+		curenv->env_tf = *tf;
+		// The trapframe on the stack should be ignored from here on.
+		tf = &curenv->env_tf;
+	}
+
+	// Record that tf is the last real trapframe so
+	// print_trapframe can print some additional information.
+	last_tf = tf;
+
+	// Dispatch based on what type of trap occurred
+	trap_dispatch(tf);
+
+	// If we made it to this point, then no other environment was
+	// scheduled, so we should return to the current environment
+	// if doing so makes sense.
+	if (curenv && curenv->env_status == ENV_RUNNING)
+		env_run(curenv);
+	else
+		sched_yield();
+}
+
+
+void
+page_fault_handler(struct Trapframe *tf)
+{
+	uint32_t fault_va;
+
+	// Read processor's CR2 register to find the faulting address
+	fault_va = rcr2();
+
+	// Handle kernel-mode page faults.
+
+	// LAB 3: Your code here.
+
+	// 怎么判断是内核模式， CPL位
+
+	if(tf->tf_cs && 3 == 0) {
+        panic("page_fault in kernel mode, fault address %d\n", fault_va);
+    }
+	
+	// We've already handled kernel-mode exceptions, so if we get here,
+	// the page fault happened in user mode.
+
+
+	// Call the environment's page fault upcall, if one exists.  Set up a
+	// page fault stack frame on the user exception stack (below
+	// UXSTACKTOP), then branch to curenv->env_pgfault_upcall.
+	//
+	// The page fault upcall might cause another page fault, in which case
+	// we branch to the page fault upcall recursively, pushing another
+	// page fault stack frame on top of the user exception stack.
+	//
+	// It is convenient for our code which returns from a page fault
+	// (lib/pfentry.S) to have one word of scratch space at the top of the
+	// trap-time stack; it allows us to more easily restore the eip/esp. In
+	// the non-recursive case, we don't have to worry about this because
+	// the top of the regular user stack is free.  In the recursive case,
+	// this means we have to leave an extra word between the current top of
+	// the exception stack and the new stack frame because the exception
+	// stack _is_ the trap-time stack.
+	//
+	// If there's no page fault upcall, the environment didn't allocate a
+	// page for its exception stack or can't write to it, or the exception
+	// stack overflows, then destroy the environment that caused the fault.
+	// Note that the grade script assumes you will first check for the page
+	// fault upcall and print the "user fault va" message below if there is
+	// none.  The remaining three checks can be combined into a single test.
+	//
+	// Hints:
+	//   user_mem_assert() and env_run() are useful here.
+	//   To change what the user environment runs, modify 'curenv->env_tf'
+	//   (the 'tf' variable points at 'curenv->env_tf').
+
+	// LAB 4: Your code here.
+
+
+	// user_mem_assert(curenv, (const void *) fault_va, PGSIZE, 0);
+	
+	// Destroy the environment that caused the fault.
+	cprintf("[%08x] user fault va %08x ip %08x\n",
+		curenv->env_id, fault_va, tf->tf_eip);
+	print_trapframe(tf);
+	env_destroy(curenv);
+}
+

lab/LAB4.si4project/Backup/trap(359).c

@@ -0,0 +1,401 @@
+#include <inc/mmu.h>
+#include <inc/x86.h>
+#include <inc/assert.h>
+
+#include <kern/pmap.h>
+#include <kern/trap.h>
+#include <kern/console.h>
+#include <kern/monitor.h>
+#include <kern/env.h>
+#include <kern/syscall.h>
+#include <kern/sched.h>
+#include <kern/kclock.h>
+#include <kern/picirq.h>
+#include <kern/cpu.h>
+#include <kern/spinlock.h>
+
+static struct Taskstate ts;
+
+/* For debugging, so print_trapframe can distinguish between printing
+ * a saved trapframe and printing the current trapframe and print some
+ * additional information in the latter case.
+ */
+static struct Trapframe *last_tf;
+
+/* Interrupt descriptor table.  (Must be built at run time because
+ * shifted function addresses can't be represented in relocation records.)
+ */
+struct Gatedesc idt[256] = { { 0 } };
+struct Pseudodesc idt_pd = {
+	sizeof(idt) - 1, (uint32_t) idt
+};
+
+
+static const char *trapname(int trapno)
+{
+	static const char * const excnames[] = {
+		"Divide error",
+		"Debug",
+		"Non-Maskable Interrupt",
+		"Breakpoint",
+		"Overflow",
+		"BOUND Range Exceeded",
+		"Invalid Opcode",
+		"Device Not Available",
+		"Double Fault",
+		"Coprocessor Segment Overrun",
+		"Invalid TSS",
+		"Segment Not Present",
+		"Stack Fault",
+		"General Protection",
+		"Page Fault",
+		"(unknown trap)",
+		"x87 FPU Floating-Point Error",
+		"Alignment Check",
+		"Machine-Check",
+		"SIMD Floating-Point Exception"
+	};
+
+	if (trapno < ARRAY_SIZE(excnames))
+		return excnames[trapno];
+	if (trapno == T_SYSCALL)
+		return "System call";
+	if (trapno >= IRQ_OFFSET && trapno < IRQ_OFFSET + 16)
+		return "Hardware Interrupt";
+	return "(unknown trap)";
+}
+
+// You will also need to modify trap_init() to initialize the idt to 
+// point to each of these entry points defined in trapentry.S;
+// the SETGATE macro will be helpful here
+void
+trap_init(void)
+{
+
+	extern struct Segdesc gdt[];
+	void divide_handler();
+	void debug_handler();
+	void nmi_handler();
+	void brkpt_handler();
+	void oflow_handler();
+	void bound_handler();
+	void device_handler();
+	void illop_handler();
+	void tss_handler();
+	void segnp_handler();
+	void stack_handler();
+	void gpflt_handler();
+	void pgflt_handler();
+	void fperr_handler();
+	void align_handler();
+	void mchk_handler();
+	void simderr_handler();
+	void syscall_handler();
+	void dblflt_handler();
+	
+	// LAB 3: Your code here.
+	// GD_KT 全局描述符， kernel text
+	SETGATE(idt[T_DIVIDE], 0, GD_KT, divide_handler, 0);
+	SETGATE(idt[T_DEBUG],  0, GD_KT, debug_handler,  0);
+	SETGATE(idt[T_NMI],    0, GD_KT, nmi_handler,    0);
+	SETGATE(idt[T_BRKPT],  0, GD_KT, brkpt_handler,  3);
+	SETGATE(idt[T_OFLOW],  0, GD_KT, oflow_handler,  0);
+	SETGATE(idt[T_BOUND],  0, GD_KT, bound_handler,  0);
+	SETGATE(idt[T_DEVICE], 0, GD_KT, device_handler, 0);
+	SETGATE(idt[T_ILLOP],  0, GD_KT, illop_handler,  0);
+	SETGATE(idt[T_DBLFLT], 0, GD_KT, dblflt_handler, 0);
+	SETGATE(idt[T_TSS],    0, GD_KT, tss_handler,    0);
+    SETGATE(idt[T_SEGNP],  0, GD_KT, segnp_handler,  0);
+    SETGATE(idt[T_STACK],  0, GD_KT, stack_handler,  0);
+    SETGATE(idt[T_GPFLT],  0, GD_KT, gpflt_handler,  0);
+    SETGATE(idt[T_PGFLT],  0, GD_KT, pgflt_handler,  0);
+    SETGATE(idt[T_FPERR],  0, GD_KT, fperr_handler,  0);
+    SETGATE(idt[T_ALIGN],  0, GD_KT, align_handler,  0);
+    SETGATE(idt[T_MCHK],   0, GD_KT, mchk_handler,   0);
+    SETGATE(idt[T_SIMDERR], 0, GD_KT, simderr_handler, 0);
+    SETGATE(idt[T_SYSCALL], 0, GD_KT, syscall_handler, 3);
+
+	// Per-CPU setup 
+	trap_init_percpu();
+}
+
+// Initialize and load the per-CPU TSS and IDT
+void
+trap_init_percpu(void)
+{
+	// The example code here sets up the Task State Segment (TSS) and
+	// the TSS descriptor for CPU 0. But it is incorrect if we are
+	// running on other CPUs because each CPU has its own kernel stack.
+	// Fix the code so that it works for all CPUs.
+	//
+	// Hints:
+	//   - The macro "thiscpu" always refers to the current CPU's
+	//     struct CpuInfo;
+	//   - The ID of the current CPU is given by cpunum() or
+	//     thiscpu->cpu_id;
+	//   - Use "thiscpu->cpu_ts" as the TSS for the current CPU,
+	//     rather than the global "ts" variable;
+	//   - Use gdt[(GD_TSS0 >> 3) + i] for CPU i's TSS descriptor;
+	//   - You mapped the per-CPU kernel stacks in mem_init_mp()
+	//   - Initialize cpu_ts.ts_iomb to prevent unauthorized environments
+	//     from doing IO (0 is not the correct value!)
+	//
+	// ltr sets a 'busy' flag in the TSS selector, so if you
+	// accidentally load the same TSS on more than one CPU, you'll
+	// get a triple fault.  If you set up an individual CPU's TSS
+	// wrong, you may not get a fault until you try to return from
+	// user space on that CPU.
+	//
+	// LAB 4: Your code here:
+	thiscpu->cpu_ts.ts_esp0 = KSTACKTOP - cpunum() * (KSTKGAP + KSTKSIZE);
+    thiscpu->cpu_ts.ts_ss0 = GD_KD;
+
+    // Initialize the TSS slot of the gdt.
+    gdt[(GD_TSS0 >> 3) + cpunum()] = SEG16(STS_T32A, (uint32_t) (&thiscpu->cpu_ts), sizeof(struct Taskstate) - 1, 0);
+    gdt[(GD_TSS0 >> 3) + cpunum()].sd_s = 0;
+
+    // Load the TSS selector (like other segment selectors, the
+    // bottom three bits are special; we leave them 0)
+    ltr(GD_TSS0 + sizeof(struct Segdesc) * cpunum());
+
+    // Load the IDT
+    lidt(&idt_pd);
+}
+
+void
+print_trapframe(struct Trapframe *tf)
+{
+	cprintf("TRAP frame at %p from CPU %d\n", tf, cpunum());
+	print_regs(&tf->tf_regs);
+	cprintf("  es   0x----%04x\n", tf->tf_es);
+	cprintf("  ds   0x----%04x\n", tf->tf_ds);
+	cprintf("  trap 0x%08x %s\n", tf->tf_trapno, trapname(tf->tf_trapno));
+	// If this trap was a page fault that just happened
+	// (so %cr2 is meaningful), print the faulting linear address.
+	if (tf == last_tf && tf->tf_trapno == T_PGFLT)
+		cprintf("  cr2  0x%08x\n", rcr2());
+	cprintf("  err  0x%08x", tf->tf_err);
+	// For page faults, print decoded fault error code:
+	// U/K=fault occurred in user/kernel mode
+	// W/R=a write/read caused the fault
+	// PR=a protection violation caused the fault (NP=page not present).
+	if (tf->tf_trapno == T_PGFLT)
+		cprintf(" [%s, %s, %s]\n",
+			tf->tf_err & 4 ? "user" : "kernel",
+			tf->tf_err & 2 ? "write" : "read",
+			tf->tf_err & 1 ? "protection" : "not-present");
+	else
+		cprintf("\n");
+	cprintf("  eip  0x%08x\n", tf->tf_eip);
+	cprintf("  cs   0x----%04x\n", tf->tf_cs);
+	cprintf("  flag 0x%08x\n", tf->tf_eflags);
+	if ((tf->tf_cs & 3) != 0) {
+		cprintf("  esp  0x%08x\n", tf->tf_esp);
+		cprintf("  ss   0x----%04x\n", tf->tf_ss);
+	}
+}
+
+void
+print_regs(struct PushRegs *regs)
+{
+	cprintf("  edi  0x%08x\n", regs->reg_edi);
+	cprintf("  esi  0x%08x\n", regs->reg_esi);
+	cprintf("  ebp  0x%08x\n", regs->reg_ebp);
+	cprintf("  oesp 0x%08x\n", regs->reg_oesp);
+	cprintf("  ebx  0x%08x\n", regs->reg_ebx);
+	cprintf("  edx  0x%08x\n", regs->reg_edx);
+	cprintf("  ecx  0x%08x\n", regs->reg_ecx);
+	cprintf("  eax  0x%08x\n", regs->reg_eax);
+}
+
+static void
+trap_dispatch(struct Trapframe *tf)
+{
+	// Handle processor exceptions.
+	// LAB 3: Your code here.
+	switch(tf->tf_trapno) {
+		case T_PGFLT:
+			page_fault_handler(tf);
+			break;
+		case T_BRKPT:
+			monitor(tf);
+			break;
+		case T_SYSCALL:
+			
+			tf->tf_regs.reg_eax = syscall(tf->tf_regs.reg_eax, 
+											tf->tf_regs.reg_edx, 
+											tf->tf_regs.reg_ecx, 
+											tf->tf_regs.reg_ebx, 
+											tf->tf_regs.reg_edi, 
+											tf->tf_regs.reg_esi);
+			break;
+		default: 
+			// Unexpected trap: The user process or the kernel has a bug.
+			print_trapframe(tf);
+			if (tf->tf_cs == GD_KT)
+				panic("unhandled trap in kernel");
+			else {
+				env_destroy(curenv);
+				return;
+			}
+			break;
+
+	}
+	
+	// Handle clock interrupts. Don't forget to acknowledge the
+	// interrupt using lapic_eoi() before calling the scheduler!
+	// LAB 4: Your code here.
+
+	
+}
+
+void
+trap(struct Trapframe *tf)
+{
+	// The environment may have set DF and some versions
+	// of GCC rely on DF being clear
+	asm volatile("cld" ::: "cc");
+
+	// Halt the CPU if some other CPU has called panic()
+	extern char *panicstr;
+	if (panicstr)
+		asm volatile("hlt");
+
+	// Re-acqurie the big kernel lock if we were halted in
+	// sched_yield()
+	if (xchg(&thiscpu->cpu_status, CPU_STARTED) == CPU_HALTED)
+		lock_kernel();
+	// Check that interrupts are disabled.  If this assertion
+	// fails, DO NOT be tempted to fix it by inserting a "cli" in
+	// the interrupt path.
+	assert(!(read_eflags() & FL_IF));
+
+	if ((tf->tf_cs & 3) == 3) {
+		// Trapped from user mode.
+		// Acquire the big kernel lock before doing any
+		// serious kernel work.
+		// LAB 4: Your code here.
+		lock_kernel();
+		assert(curenv);
+		
+		// Garbage collect if current enviroment is a zombie
+		if (curenv->env_status == ENV_DYING) {
+			env_free(curenv);
+			curenv = NULL;
+			sched_yield();
+		}
+
+		// Copy trap frame (which is currently on the stack)
+		// into 'curenv->env_tf', so that running the environment
+		// will restart at the trap point.
+		curenv->env_tf = *tf;
+		// The trapframe on the stack should be ignored from here on.
+		tf = &curenv->env_tf;
+	}
+
+	// Record that tf is the last real trapframe so
+	// print_trapframe can print some additional information.
+	last_tf = tf;
+
+	// Dispatch based on what type of trap occurred
+	trap_dispatch(tf);
+
+	// If we made it to this point, then no other environment was
+	// scheduled, so we should return to the current environment
+	// if doing so makes sense.
+	if (curenv && curenv->env_status == ENV_RUNNING)
+		env_run(curenv);
+	else
+		sched_yield();
+}
+
+
+void
+page_fault_handler(struct Trapframe *tf)
+{
+	uint32_t fault_va;
+
+	// Read processor's CR2 register to find the faulting address
+	fault_va = rcr2();
+
+	// Handle kernel-mode page faults.
+
+	// LAB 3: Your code here.
+
+	// 怎么判断是内核模式， CPL位
+
+	if(tf->tf_cs && 3 == 0) {
+        panic("page_fault in kernel mode, fault address %d\n", fault_va);
+    }
+	
+	// We've already handled kernel-mode exceptions, so if we get here,
+	// the page fault happened in user mode.
+
+
+	// Call the environment's page fault upcall, if one exists.  Set up a
+	// page fault stack frame on the user exception stack (below
+	// UXSTACKTOP), then branch to curenv->env_pgfault_upcall.
+	//
+	// The page fault upcall might cause another page fault, in which case
+	// we branch to the page fault upcall recursively, pushing another
+	// page fault stack frame on top of the user exception stack.
+	//
+	// It is convenient for our code which returns from a page fault
+	// (lib/pfentry.S) to have one word of scratch space at the top of the
+	// trap-time stack; it allows us to more easily restore the eip/esp. In
+	// the non-recursive case, we don't have to worry about this because
+	// the top of the regular user stack is free.  In the recursive case,
+	// this means we have to leave an extra word between the current top of
+	// the exception stack and the new stack frame because the exception
+	// stack _is_ the trap-time stack.
+	//
+	// If there's no page fault upcall, the environment didn't allocate a
+	// page for its exception stack or can't write to it, or the exception
+	// stack overflows, then destroy the environment that caused the fault.
+	// Note that the grade script assumes you will first check for the page
+	// fault upcall and print the "user fault va" message below if there is
+	// none.  The remaining three checks can be combined into a single test.
+	//
+	// Hints:
+	//   user_mem_assert() and env_run() are useful here.
+	//   To change what the user environment runs, modify 'curenv->env_tf'
+	//   (the 'tf' variable points at 'curenv->env_tf').
+
+	// LAB 4: Your code here.
+	struct UTrapframe *utf;
+	
+	if (curenv->env_pgfault_upcall) {
+		
+		if (tf->tf_esp >= UXSTACKTOP-PGSIZE && tf->tf_esp < UXSTACKTOP) {
+			// 异常模式下陷入
+			utf = (struct UTrapframe *)(tf->tf_esp - sizeof(struct UTrapframe) - 4);
+
+		}
+		else {
+			// 非异常模式下陷入
+			utf = (struct UTrapframe *)(UXSTACKTOP - sizeof(struct UTrapframe) - 4);	
+		}
+		// 检查异常栈是否溢出
+		user_mem_assert(curenv, (const void *) utf, sizeof(struct UTrapframe), PTE_U|PTE_W);
+			
+		utf->utf_fault_va = fault_va;
+		utf->utf_err      = tf->tf_trapno;
+		utf->utf_regs     = tf->tf_regs;
+		utf->utf_eflags   = tf->tf_eflags;
+		// 保存上次陷入时现场，用于返回
+		utf->utf_eip      = tf->tf_eip;
+		utf->utf_esp      = tf->tf_esp;
+		// 再次转向执行
+		tf->tf_eip        = (uint32_t) curenv->env_pgfault_upcall;
+		tf->tf_esp        = (uint32_t) utf;
+		env_run(curenv);
+	}
+	
+	
+	// Destroy the environment that caused the fault.
+	cprintf("[%08x] user fault va %08x ip %08x\n",
+		curenv->env_id, fault_va, tf->tf_eip);
+	print_trapframe(tf);
+	env_destroy(curenv);
+}
+

lab/LAB4.si4project/Backup/trap(6309).c

@@ -0,0 +1,384 @@
+#include <inc/mmu.h>
+#include <inc/x86.h>
+#include <inc/assert.h>
+
+#include <kern/pmap.h>
+#include <kern/trap.h>
+#include <kern/console.h>
+#include <kern/monitor.h>
+#include <kern/env.h>
+#include <kern/syscall.h>
+#include <kern/sched.h>
+#include <kern/kclock.h>
+#include <kern/picirq.h>
+#include <kern/cpu.h>
+#include <kern/spinlock.h>
+
+static struct Taskstate ts;
+
+/* For debugging, so print_trapframe can distinguish between printing
+ * a saved trapframe and printing the current trapframe and print some
+ * additional information in the latter case.
+ */
+static struct Trapframe *last_tf;
+
+/* Interrupt descriptor table.  (Must be built at run time because
+ * shifted function addresses can't be represented in relocation records.)
+ */
+struct Gatedesc idt[256] = { { 0 } };
+struct Pseudodesc idt_pd = {
+	sizeof(idt) - 1, (uint32_t) idt
+};
+
+
+static const char *trapname(int trapno)
+{
+	static const char * const excnames[] = {
+		"Divide error",
+		"Debug",
+		"Non-Maskable Interrupt",
+		"Breakpoint",
+		"Overflow",
+		"BOUND Range Exceeded",
+		"Invalid Opcode",
+		"Device Not Available",
+		"Double Fault",
+		"Coprocessor Segment Overrun",
+		"Invalid TSS",
+		"Segment Not Present",
+		"Stack Fault",
+		"General Protection",
+		"Page Fault",
+		"(unknown trap)",
+		"x87 FPU Floating-Point Error",
+		"Alignment Check",
+		"Machine-Check",
+		"SIMD Floating-Point Exception"
+	};
+
+	if (trapno < ARRAY_SIZE(excnames))
+		return excnames[trapno];
+	if (trapno == T_SYSCALL)
+		return "System call";
+	if (trapno >= IRQ_OFFSET && trapno < IRQ_OFFSET + 16)
+		return "Hardware Interrupt";
+	return "(unknown trap)";
+}
+
+// You will also need to modify trap_init() to initialize the idt to 
+// point to each of these entry points defined in trapentry.S;
+// the SETGATE macro will be helpful here
+void
+trap_init(void)
+{
+
+	extern struct Segdesc gdt[];
+	void divide_handler();
+	void debug_handler();
+	void nmi_handler();
+	void brkpt_handler();
+	void oflow_handler();
+	void bound_handler();
+	void device_handler();
+	void illop_handler();
+	void tss_handler();
+	void segnp_handler();
+	void stack_handler();
+	void gpflt_handler();
+	void pgflt_handler();
+	void fperr_handler();
+	void align_handler();
+	void mchk_handler();
+	void simderr_handler();
+	void syscall_handler();
+	void dblflt_handler();
+	
+	// LAB 3: Your code here.
+	// GD_KT 全局描述符， kernel text
+	SETGATE(idt[T_DIVIDE], 0, GD_KT, divide_handler, 0);
+	SETGATE(idt[T_DEBUG],  0, GD_KT, debug_handler,  0);
+	SETGATE(idt[T_NMI],    0, GD_KT, nmi_handler,    0);
+	SETGATE(idt[T_BRKPT],  0, GD_KT, brkpt_handler,  3);
+	SETGATE(idt[T_OFLOW],  0, GD_KT, oflow_handler,  0);
+	SETGATE(idt[T_BOUND],  0, GD_KT, bound_handler,  0);
+	SETGATE(idt[T_DEVICE], 0, GD_KT, device_handler, 0);
+	SETGATE(idt[T_ILLOP],  0, GD_KT, illop_handler,  0);
+	SETGATE(idt[T_DBLFLT], 0, GD_KT, dblflt_handler, 0);
+	SETGATE(idt[T_TSS],    0, GD_KT, tss_handler,    0);
+    SETGATE(idt[T_SEGNP],  0, GD_KT, segnp_handler,  0);
+    SETGATE(idt[T_STACK],  0, GD_KT, stack_handler,  0);
+    SETGATE(idt[T_GPFLT],  0, GD_KT, gpflt_handler,  0);
+    SETGATE(idt[T_PGFLT],  0, GD_KT, pgflt_handler,  0);
+    SETGATE(idt[T_FPERR],  0, GD_KT, fperr_handler,  0);
+    SETGATE(idt[T_ALIGN],  0, GD_KT, align_handler,  0);
+    SETGATE(idt[T_MCHK],   0, GD_KT, mchk_handler,   0);
+    SETGATE(idt[T_SIMDERR], 0, GD_KT, simderr_handler, 0);
+    SETGATE(idt[T_SYSCALL], 0, GD_KT, syscall_handler, 3);
+
+	// Per-CPU setup 
+	trap_init_percpu();
+}
+
+// Initialize and load the per-CPU TSS and IDT
+void
+trap_init_percpu(void)
+{
+	// The example code here sets up the Task State Segment (TSS) and
+	// the TSS descriptor for CPU 0. But it is incorrect if we are
+	// running on other CPUs because each CPU has its own kernel stack.
+	// Fix the code so that it works for all CPUs.
+	//
+	// Hints:
+	//   - The macro "thiscpu" always refers to the current CPU's
+	//     struct CpuInfo;
+	//   - The ID of the current CPU is given by cpunum() or
+	//     thiscpu->cpu_id;
+	//   - Use "thiscpu->cpu_ts" as the TSS for the current CPU,
+	//     rather than the global "ts" variable;
+	//   - Use gdt[(GD_TSS0 >> 3) + i] for CPU i's TSS descriptor;
+	//   - You mapped the per-CPU kernel stacks in mem_init_mp()
+	//   - Initialize cpu_ts.ts_iomb to prevent unauthorized environments
+	//     from doing IO (0 is not the correct value!)
+	//
+	// ltr sets a 'busy' flag in the TSS selector, so if you
+	// accidentally load the same TSS on more than one CPU, you'll
+	// get a triple fault.  If you set up an individual CPU's TSS
+	// wrong, you may not get a fault until you try to return from
+	// user space on that CPU.
+	//
+	// LAB 4: Your code here:
+	thiscpu->cpu_ts.ts_esp0 = KSTACKTOP - cpunum() * (KSTKGAP + KSTKSIZE);
+    thiscpu->cpu_ts.ts_ss0 = GD_KD;
+
+    // Initialize the TSS slot of the gdt.
+    gdt[(GD_TSS0 >> 3) + cpunum()] = SEG16(STS_T32A, (uint32_t) (&thiscpu->cpu_ts), sizeof(struct Taskstate) - 1, 0);
+    gdt[(GD_TSS0 >> 3) + cpunum()].sd_s = 0;
+
+    // Load the TSS selector (like other segment selectors, the
+    // bottom three bits are special; we leave them 0)
+    ltr(GD_TSS0 + sizeof(struct Segdesc) * cpunum());
+
+    // Load the IDT
+    lidt(&idt_pd);
+}
+
+void
+print_trapframe(struct Trapframe *tf)
+{
+	cprintf("TRAP frame at %p from CPU %d\n", tf, cpunum());
+	print_regs(&tf->tf_regs);
+	cprintf("  es   0x----%04x\n", tf->tf_es);
+	cprintf("  ds   0x----%04x\n", tf->tf_ds);
+	cprintf("  trap 0x%08x %s\n", tf->tf_trapno, trapname(tf->tf_trapno));
+	// If this trap was a page fault that just happened
+	// (so %cr2 is meaningful), print the faulting linear address.
+	if (tf == last_tf && tf->tf_trapno == T_PGFLT)
+		cprintf("  cr2  0x%08x\n", rcr2());
+	cprintf("  err  0x%08x", tf->tf_err);
+	// For page faults, print decoded fault error code:
+	// U/K=fault occurred in user/kernel mode
+	// W/R=a write/read caused the fault
+	// PR=a protection violation caused the fault (NP=page not present).
+	if (tf->tf_trapno == T_PGFLT)
+		cprintf(" [%s, %s, %s]\n",
+			tf->tf_err & 4 ? "user" : "kernel",
+			tf->tf_err & 2 ? "write" : "read",
+			tf->tf_err & 1 ? "protection" : "not-present");
+	else
+		cprintf("\n");
+	cprintf("  eip  0x%08x\n", tf->tf_eip);
+	cprintf("  cs   0x----%04x\n", tf->tf_cs);
+	cprintf("  flag 0x%08x\n", tf->tf_eflags);
+	if ((tf->tf_cs & 3) != 0) {
+		cprintf("  esp  0x%08x\n", tf->tf_esp);
+		cprintf("  ss   0x----%04x\n", tf->tf_ss);
+	}
+}
+
+void
+print_regs(struct PushRegs *regs)
+{
+	cprintf("  edi  0x%08x\n", regs->reg_edi);
+	cprintf("  esi  0x%08x\n", regs->reg_esi);
+	cprintf("  ebp  0x%08x\n", regs->reg_ebp);
+	cprintf("  oesp 0x%08x\n", regs->reg_oesp);
+	cprintf("  ebx  0x%08x\n", regs->reg_ebx);
+	cprintf("  edx  0x%08x\n", regs->reg_edx);
+	cprintf("  ecx  0x%08x\n", regs->reg_ecx);
+	cprintf("  eax  0x%08x\n", regs->reg_eax);
+}
+
+static void
+trap_dispatch(struct Trapframe *tf)
+{
+	// Handle processor exceptions.
+	// LAB 3: Your code here.
+	switch(tf->tf_trapno) {
+		case T_PGFLT:
+			page_fault_handler(tf);
+			break;
+		case T_BRKPT:
+			monitor(tf);
+			break;
+		case T_SYSCALL:
+			
+			tf->tf_regs.reg_eax = syscall(tf->tf_regs.reg_eax, 
+											tf->tf_regs.reg_edx, 
+											tf->tf_regs.reg_ecx, 
+											tf->tf_regs.reg_ebx, 
+											tf->tf_regs.reg_edi, 
+											tf->tf_regs.reg_esi);
+			break;
+		default: 
+			// Unexpected trap: The user process or the kernel has a bug.
+			print_trapframe(tf);
+			if (tf->tf_cs == GD_KT)
+				panic("unhandled trap in kernel");
+			else {
+				env_destroy(curenv);
+				return;
+			}
+			break;
+
+	}
+	
+	// Handle clock interrupts. Don't forget to acknowledge the
+	// interrupt using lapic_eoi() before calling the scheduler!
+	// LAB 4: Your code here.
+
+	// Unexpected trap: The user process or the kernel has a bug.
+	print_trapframe(tf);
+	if (tf->tf_cs == GD_KT)
+		panic("unhandled trap in kernel");
+	else {
+		env_destroy(curenv);
+		return;
+
+	}
+	
+}
+
+void
+trap(struct Trapframe *tf)
+{
+	// The environment may have set DF and some versions
+	// of GCC rely on DF being clear
+	asm volatile("cld" ::: "cc");
+
+	// Halt the CPU if some other CPU has called panic()
+	extern char *panicstr;
+	if (panicstr)
+		asm volatile("hlt");
+
+	// Re-acqurie the big kernel lock if we were halted in
+	// sched_yield()
+	if (xchg(&thiscpu->cpu_status, CPU_STARTED) == CPU_HALTED)
+		lock_kernel();
+	// Check that interrupts are disabled.  If this assertion
+	// fails, DO NOT be tempted to fix it by inserting a "cli" in
+	// the interrupt path.
+	assert(!(read_eflags() & FL_IF));
+
+	if ((tf->tf_cs & 3) == 3) {
+		// Trapped from user mode.
+		// Acquire the big kernel lock before doing any
+		// serious kernel work.
+		// LAB 4: Your code here.
+		lock_kernel();
+		assert(curenv);
+		
+		// Garbage collect if current enviroment is a zombie
+		if (curenv->env_status == ENV_DYING) {
+			env_free(curenv);
+			curenv = NULL;
+			sched_yield();
+		}
+
+		// Copy trap frame (which is currently on the stack)
+		// into 'curenv->env_tf', so that running the environment
+		// will restart at the trap point.
+		curenv->env_tf = *tf;
+		// The trapframe on the stack should be ignored from here on.
+		tf = &curenv->env_tf;
+	}
+
+	// Record that tf is the last real trapframe so
+	// print_trapframe can print some additional information.
+	last_tf = tf;
+
+	// Dispatch based on what type of trap occurred
+	trap_dispatch(tf);
+
+	// If we made it to this point, then no other environment was
+	// scheduled, so we should return to the current environment
+	// if doing so makes sense.
+	if (curenv && curenv->env_status == ENV_RUNNING)
+		env_run(curenv);
+	else
+		sched_yield();
+}
+
+
+void
+page_fault_handler(struct Trapframe *tf)
+{
+	uint32_t fault_va;
+
+	// Read processor's CR2 register to find the faulting address
+	fault_va = rcr2();
+
+	// Handle kernel-mode page faults.
+
+	// LAB 3: Your code here.
+
+	// 怎么判断是内核模式， CPL位
+
+	if(tf->tf_cs && 3 == 0) {
+        panic("page_fault in kernel mode, fault address %d\n", fault_va);
+    }
+	
+	// We've already handled kernel-mode exceptions, so if we get here,
+	// the page fault happened in user mode.
+
+
+	// Call the environment's page fault upcall, if one exists.  Set up a
+	// page fault stack frame on the user exception stack (below
+	// UXSTACKTOP), then branch to curenv->env_pgfault_upcall.
+	//
+	// The page fault upcall might cause another page fault, in which case
+	// we branch to the page fault upcall recursively, pushing another
+	// page fault stack frame on top of the user exception stack.
+	//
+	// It is convenient for our code which returns from a page fault
+	// (lib/pfentry.S) to have one word of scratch space at the top of the
+	// trap-time stack; it allows us to more easily restore the eip/esp. In
+	// the non-recursive case, we don't have to worry about this because
+	// the top of the regular user stack is free.  In the recursive case,
+	// this means we have to leave an extra word between the current top of
+	// the exception stack and the new stack frame because the exception
+	// stack _is_ the trap-time stack.
+	//
+	// If there's no page fault upcall, the environment didn't allocate a
+	// page for its exception stack or can't write to it, or the exception
+	// stack overflows, then destroy the environment that caused the fault.
+	// Note that the grade script assumes you will first check for the page
+	// fault upcall and print the "user fault va" message below if there is
+	// none.  The remaining three checks can be combined into a single test.
+	//
+	// Hints:
+	//   user_mem_assert() and env_run() are useful here.
+	//   To change what the user environment runs, modify 'curenv->env_tf'
+	//   (the 'tf' variable points at 'curenv->env_tf').
+
+	// LAB 4: Your code here.
+
+
+	// user_mem_assert(curenv, (const void *) fault_va, PGSIZE, 0);
+	
+	// Destroy the environment that caused the fault.
+	cprintf("[%08x] user fault va %08x ip %08x\n",
+		curenv->env_id, fault_va, tf->tf_eip);
+	print_trapframe(tf);
+	env_destroy(curenv);
+}
+

lab/LAB4.si4project/Backup/trapentry(2731).S

@@ -0,0 +1,100 @@
+/* See COPYRIGHT for copyright information. */
+
+#include <inc/mmu.h>
+#include <inc/memlayout.h>
+#include <inc/trap.h>
+
+#include <kern/picirq.h>
+
+
+###################################################################
+# exceptions/interrupts
+###################################################################
+
+/* TRAPHANDLER defines a globally-visible function for handling a trap.
+ * It pushes a trap number onto the stack, then jumps to _alltraps.
+ * Use TRAPHANDLER for traps where the CPU automatically pushes an error code.
+ *
+ * You shouldn't call a TRAPHANDLER function from C, but you may
+ * need to _declare_ one in C (for instance, to get a function pointer
+ * during IDT setup).  You can declare the function with
+ *   void NAME();
+ * where NAME is the argument passed to TRAPHANDLER.
+ */
+#define TRAPHANDLER(name, num)						\
+	.globl name;		/* define global symbol for 'name' */	\
+	.type name, @function;	/* symbol type is function */		\
+	.align 2;		/* align function definition */		\
+	name:			/* function starts here */		\
+	pushl $(num);							\
+	jmp _alltraps
+
+/* Use TRAPHANDLER_NOEC for traps where the CPU doesn't push an error code.
+ * It pushes a 0 in place of the error code, so the trap frame has the same
+ * format in either case.
+
+ * tarp handler no error code
+ */
+ 
+#define TRAPHANDLER_NOEC(name, num)					\
+	.globl name;							\
+	.type name, @function;						\
+	.align 2;							\
+	name:								\
+	pushl $0;							\
+	pushl $(num);							\
+	jmp _alltraps
+
+.text
+
+/*
+ * 我们知道哪些trap是有错误代码的？ https://wiki.osdev.org/Exceptions
+ * Lab 3: Your code here for generating entry points for the different traps.
+ */
+TRAPHANDLER_NOEC(divide_handler, T_DIVIDE);
+TRAPHANDLER_NOEC(debug_handler, T_DEBUG);
+TRAPHANDLER_NOEC(nmi_handler, T_NMI);
+TRAPHANDLER_NOEC(brkpt_handler, T_BRKPT);
+TRAPHANDLER_NOEC(oflow_handler, T_OFLOW);
+TRAPHANDLER_NOEC(bound_handler, T_BOUND);
+TRAPHANDLER_NOEC(illop_handler, T_ILLOP);
+TRAPHANDLER_NOEC(device_handler, T_DEVICE);
+TRAPHANDLER(dblflt_handler, T_DBLFLT);
+TRAPHANDLER(tss_handler, T_TSS);
+TRAPHANDLER(segnp_handler, T_SEGNP);
+TRAPHANDLER(stack_handler, T_STACK);
+TRAPHANDLER(gpflt_handler, T_GPFLT);
+TRAPHANDLER(pgflt_handler, T_PGFLT);
+TRAPHANDLER_NOEC(fperr_handler, T_FPERR);
+TRAPHANDLER(align_handler, T_ALIGN);
+TRAPHANDLER_NOEC(mchk_handler, T_MCHK);
+TRAPHANDLER_NOEC(simderr_handler, T_SIMDERR);
+TRAPHANDLER_NOEC(syscall_handler, T_SYSCALL);
+
+/*
+Your _alltraps should:
+	1. push values to make the stack look like a struct Trapframe
+	2. load GD_KD into %ds and %es
+	3. pushl %esp to pass a pointer to the Trapframe as an argument to trap()
+	4. call trap (can trap ever return?)
+*/
+
+/*
+ * Lab 3: Your code here for _alltraps
+ *what is padding ? 填充 pushl %ds;小端模式，是指数据的高字节保存在内存的高地址中
+ */
+.globl _alltraps
+_alltraps:
+	
+	pushl %ds;
+	pushl %es;
+	pushal;
+	
+	movw $GD_KD, %ax;
+	movw %ax, %ds;
+	movw %ax, %es;
+
+	/*push esp, trap 能自己读esp, 我有点觉得是赋值*/
+	pushl %esp;        
+	call trap
+	

lab/LAB4.si4project/Backup/trapentry(7165).S

@@ -0,0 +1,100 @@
+/* See COPYRIGHT for copyright information. */
+
+#include <inc/mmu.h>
+#include <inc/memlayout.h>
+#include <inc/trap.h>
+
+#include <kern/picirq.h>
+
+
+###################################################################
+# exceptions/interrupts
+###################################################################
+
+/* TRAPHANDLER defines a globally-visible function for handling a trap.
+ * It pushes a trap number onto the stack, then jumps to _alltraps.
+ * Use TRAPHANDLER for traps where the CPU automatically pushes an error code.
+ *
+ * You shouldn't call a TRAPHANDLER function from C, but you may
+ * need to _declare_ one in C (for instance, to get a function pointer
+ * during IDT setup).  You can declare the function with
+ *   void NAME();
+ * where NAME is the argument passed to TRAPHANDLER.
+ */
+#define TRAPHANDLER(name, num)						\
+	.globl name;		/* define global symbol for 'name' */	\
+	.type name, @function;	/* symbol type is function */		\
+	.align 2;		/* align function definition */		\
+	name:			/* function starts here */		\
+	pushl $(num);							\
+	jmp _alltraps
+
+/* Use TRAPHANDLER_NOEC for traps where the CPU doesn't push an error code.
+ * It pushes a 0 in place of the error code, so the trap frame has the same
+ * format in either case.
+
+ * tarp handler no error code
+ */
+ 
+#define TRAPHANDLER_NOEC(name, num)					\
+	.globl name;							\
+	.type name, @function;						\
+	.align 2;							\
+	name:								\
+	pushl $0;							\
+	pushl $(num);							\
+	jmp _alltraps
+
+.text
+
+/*
+ * 我们知道哪些trap是有错误代码的？ https://wiki.osdev.org/Exceptions
+ * Lab 3: Your code here for generating entry points for the different traps.
+ */
+TRAPHANDLER_NOEC(divide_handler, T_DIVIDE);
+TRAPHANDLER_NOEC(debug_handler, T_DEBUG);
+TRAPHANDLER_NOEC(nmi_handler, T_NMI);
+TRAPHANDLER_NOEC(brkpt_handler, T_BRKPT);
+TRAPHANDLER_NOEC(oflow_handler, T_OFLOW);
+TRAPHANDLER_NOEC(bound_handler, T_BOUND);
+TRAPHANDLER_NOEC(illop_handler, T_ILLOP);
+TRAPHANDLER_NOEC(device_handler, T_DEVICE);
+TRAPHANDLER(dblflt_handler, T_DBLFLT);
+TRAPHANDLER(tss_handler, T_TSS);
+TRAPHANDLER(segnp_handler, T_SEGNP);
+TRAPHANDLER(stack_handler, T_STACK);
+TRAPHANDLER(gpflt_handler, T_GPFLT);
+TRAPHANDLER(pgflt_handler, T_PGFLT);
+TRAPHANDLER_NOEC(fperr_handler, T_FPERR);
+TRAPHANDLER(align_handler, T_ALIGN);
+TRAPHANDLER_NOEC(mchk_handler, T_MCHK);
+TRAPHANDLER_NOEC(simderr_handler, T_SIMDERR);
+TRAPHANDLER_NOEC(syscall_handler, T_SYSCALL);
+
+/*
+Your _alltraps should:
+	1. push values to make the stack look like a struct Trapframe
+	2. load GD_KD into %ds and %es
+	3. pushl %esp to pass a pointer to the Trapframe as an argument to trap()
+	4. call trap (can trap ever return?)
+*/
+
+/*
+ * Lab 3: Your code here for _alltraps
+ *what is padding ? 填充 pushl %ds;小端模式，是指数据的高字节保存在内存的高地址中
+ */
+.globl _alltraps
+_alltraps:
+	
+	pushl %ds;
+	pushl %es;
+	pushal;
+	
+	movw $GD_KD, %ax;
+	movw %ax, %ds;
+	movw %ax, %es;
+
+	/*push esp, trap 能自己读esp, 我有点觉得是赋值*/
+	pushl %esp;        
+	call trap
+	

lab/LAB4.si4project/LAB4.SearchResults

@@ -0,0 +1,4 @@
+---- sched_halt Matches (3 in 1 files) ----
+sched.c (kern) line 8 : void sched_halt(void);
+sched_yield in sched.c (kern) : 	sched_halt();
+sched.c (kern) line 56 : sched_halt(void)

lab/LAB4.si4project/LAB4.bookmarks.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<SourceInsightBookmarks
+	AppVer="4.00.0084"
+	AppVerMinReader="4.00.0009"
+	>
+	<Bookmarks/>
+</SourceInsightBookmarks>

lab/LAB4.si4project/LAB4.siproj_settings.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<ProjectSettings
+	AppVer="4.00.0084"
+	AppVerMinReader="4.00.0034"
+	GlobalConfiguration="1"
+	GlobalWorkspace="0"
+	LocalsInDb="0"
+	IndexMembers="1"
+	IndexFragments="1"
+	UseMasterFileList="0"
+	SourceDir="..\"
+	BackupDir="%PROJECT_DATA_DIR%\Backup"
+	MasterFileList="%PROJECT_SOURCE_DIR%\%PROJECT_NAME%_filelist.txt"
+	IsImportProject="0"
+	>
+	<Imports>
+		<ImportedLibs/>
+	</Imports>
+	<ParseConditions>
+		<Defines/>
+	</ParseConditions>
+</ProjectSettings>

lab/LAB4.si4project/LAB4.snippets.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<SourceInsightCodeSnippets
+	AppVer="4.00.0084"
+	AppVerMinReader="4.00.0019"
+	>
+	<SnippetList/>
+</SourceInsightCodeSnippets>