如何编写从汇编代码调用的C函数(How to write a C function invoked from assembly code)

 我需要编写一个C函数，它将从linux内核中的汇编代码中调用。 
 
 应该考虑哪些特殊问题？ 
 
 我有一些想法，但任何人都可以提供更多细节： 
 
 （1）召集会议 
 
 确保组件中的呼叫者和c中的被叫者握手良好。 但是我应该使用哪种调用约定？ 如何声明c函数并在汇编代码中声明它？ 
 
 （2）保护寄存器 
 
 在调用之前，应将某些寄存器保存在程序集中。 我粗略记得他们是eax，ecx和edx。 但我不需要保存它们，除非我需要在调用C函数之前引用旧值，对吧？ 
 
 还有什么其他问题？ 

I need to write a C function that will be invoked from assembly code in linux kernel.
 
What special issues should be taken into account?
 
I have some in mind, but can anybody provide more details:
 
(1) Calling convention
 
Make sure the caller in assembly and the callee in c shake hands well. But which calling convention should I use? How can I declare the c function and declare it in assembly code?
 
(2) Protect registers
 
Some registers should be saved in the assembly before the invoke. I roughly remember they are eax, ecx and edx. But I don't have to save them unless I need to refer to the old value before the invoke to the C function, right?
 
What are other issues?

原文：https://stackoverflow.com/questions/10061324