fix mm direcotry

This commit is contained in:
Dongliang Mu
2018-03-15 00:25:26 -04:00
parent 1c8f44e45b
commit 1917026567
10 changed files with 23 additions and 23 deletions

View File

@@ -4,7 +4,7 @@ Kernel initialization. Part 7.
The End of the architecture-specific initialization, almost...
================================================================================
This is the seventh part of the Linux Kernel initialization process which covers insides of the `setup_arch` function from the [arch/x86/kernel/setup.c](https://github.com/torvalds/linux/blob/master/arch/x86/kernel/setup.c#L861). As you can know from the previous [parts](http://0xax.gitbooks.io/linux-insides/content/Initialization/index.html), the `setup_arch` function does some architecture-specific (in our case it is [x86_64](http://en.wikipedia.org/wiki/X86-64)) initialization stuff like reserving memory for kernel code/data/bss, early scanning of the [Desktop Management Interface](http://en.wikipedia.org/wiki/Desktop_Management_Interface), early dump of the [PCI](http://en.wikipedia.org/wiki/PCI) device and many many more. If you have read the previous [part](http://xinqiu.gitbooks.io/linux-insides-cn/content/Initialization/%20linux-initialization-6.html), you can remember that we've finished it at the `setup_real_mode` function. In the next step, as we set limit of the [memblock](http://xinqiu.gitbooks.io/linux-insides-cn/content/mm/linux-mm-1.html) to the all mapped pages, we can see the call of the `setup_log_buf` function from the [kernel/printk/printk.c](https://github.com/torvalds/linux/blob/master/kernel/printk/printk.c).
This is the seventh part of the Linux Kernel initialization process which covers insides of the `setup_arch` function from the [arch/x86/kernel/setup.c](https://github.com/torvalds/linux/blob/master/arch/x86/kernel/setup.c#L861). As you can know from the previous [parts](http://0xax.gitbooks.io/linux-insides/content/Initialization/index.html), the `setup_arch` function does some architecture-specific (in our case it is [x86_64](http://en.wikipedia.org/wiki/X86-64)) initialization stuff like reserving memory for kernel code/data/bss, early scanning of the [Desktop Management Interface](http://en.wikipedia.org/wiki/Desktop_Management_Interface), early dump of the [PCI](http://en.wikipedia.org/wiki/PCI) device and many many more. If you have read the previous [part](http://xinqiu.gitbooks.io/linux-insides-cn/content/Initialization/%20linux-initialization-6.html), you can remember that we've finished it at the `setup_real_mode` function. In the next step, as we set limit of the [memblock](http://xinqiu.gitbooks.io/linux-insides-cn/content/MM/linux-mm-1.html) to the all mapped pages, we can see the call of the `setup_log_buf` function from the [kernel/printk/printk.c](https://github.com/torvalds/linux/blob/master/kernel/printk/printk.c).
The `setup_log_buf` function setups kernel cyclic buffer and its length depends on the `CONFIG_LOG_BUF_SHIFT` configuration option. As we can read from the documentation of the `CONFIG_LOG_BUF_SHIFT` it can be between `12` and `21`. In the insides, buffer defined as array of chars:
@@ -296,7 +296,7 @@ BUILD_BUG_ON((unsigned long)__fix_to_virt(VSYSCALL_PAGE) !=
(unsigned long)VSYSCALL_ADDR);
```
Now `vsyscall` area is in the `fix-mapped` area. That's all about `map_vsyscall`, if you do not know anything about fix-mapped addresses, you can read [Fix-Mapped Addresses and ioremap](http://xinqiu.gitbooks.io/linux-insides-cn/content/mm/linux-mm-2.html). We will see more about `vsyscalls` in the `vsyscalls and vdso` part.
Now `vsyscall` area is in the `fix-mapped` area. That's all about `map_vsyscall`, if you do not know anything about fix-mapped addresses, you can read [Fix-Mapped Addresses and ioremap](http://xinqiu.gitbooks.io/linux-insides-cn/content/MM/linux-mm-2.html). We will see more about `vsyscalls` in the `vsyscalls and vdso` part.
Getting the SMP configuration
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