请教一个X64 LINUX内核寄存器调用约定的问题

safedead

X64 LINUX应用程序的调用约定我找到了，网上可以下载到AMD64 SYS-V ABI
如果是在LINUX内核里呢？我记得LDD3说不要在内核模块中使用浮点寄存器，因为内核线程切换时不维护浮点堆栈
完整的LINUX X64内核ABI应该去哪里找呢？能够在内核源码目录中找到吗?

帅绝人寰

kernel和userspace是一样的

只有一点需要注意， 使用syscall指令时，有个gpr用来做特殊用途了， 具体请自行search google

safedead

回复 2# 帅绝人寰


THX

google了LINUX + kernel + ABI

看到的内容相当崩溃，LINUX内核果然是猪突猛进(没有历史负担其实也很好)，既不保证API的延续性也不保证ABI的延续性
只能是开发哪个版本的内核模块就得看对应源代码的Documentation/ABI/下面的内容
最近需要写点汇编小程序在模块里，看来是绕不开内核ABI这块内容了。

safedead

回复 2# 帅绝人寰


找到详细资料了，就在
System V Application Binary Interface AMD64 Architecture Processor Supplement

附录A.2关于寄存器的使用约定：

A.2 AMD64 Linux Kernel Conventions

1. User-level applications use as integer registers for passing the sequence
%rdi, %rsi, %rdx, %rcx, %r8 and %r9. The kernel interface uses %rdi,
%rsi, %rdx, %r10, %r8 and %r9.

2. A system-call is done via the syscall instruction. The kernel destroys
registers %rcx and %r11.

3. The number of the syscall has to be passed in register %rax.
4. System-calls are limited to six arguments, no argument is passed directly on
the stack.

5. Returning from the syscall, register %rax contains the result of the
system-call. A value in the range between -4095 and -1 indicates an error,
it is -errno.

6. Only values of class INTEGER or class MEMORY are passed to the kernel.