Equivalent of the `SYM_FUNC_START` macro in linux userspace?

Asked Apr 17 '23 at 17:09

Active Apr 17 '23 at 20:24

Viewed 34 times

I am looking for a userspace equivalent to the SYM_FUNC_START macro from the linux kernel (include <linux/linkage.h>). I want to declare a function in an .S assembly file like so:

SYM_FUNC_START(assembly_func)
 push %rbx
 mov %rdi, %r8 // %rdi should contain the first argument 
 pob %rbx
 ret 
SYM_FUNC_END(assembly_func)

And then be able to define it in a .h file like so:

void assembly_func(int64_t first_arg);

And call it from normal .c code. Is this also possible from userspace?

asked Apr 17 '23 at 17:09

cryptobeginner

this has nothing to do with these macros – user253751 Apr 17 '23 at 17:21
Oh, even better! How can I declare a function in a .S file? – cryptobeginner Apr 17 '23 at 17:22
1

You simply put a label with the function name at the beginning of the code. `function_name:` – Barmar Apr 17 '23 at 17:29
1

`.globl foo / foo: ret` in `foo.S` (replace `/` with a new line) and `void foo(); int main(void) { foo(); return 0; }` in `main.c`. Then `gcc foo.S main.c -o bar`. Double-check that. – Margaret Bloom Apr 17 '23 at 17:48

Equivalent of the `SYM_FUNC_START` macro in linux userspace?

0 Answers0