diff options
| author | Zhangjin Wu <falcon@tinylab.org> | 2023-07-15 21:27:49 +0300 |
|---|---|---|
| committer | Willy Tarreau <w@1wt.eu> | 2023-08-23 05:40:22 +0300 |
| commit | 539287d75178fd77c195520477dcd35a4d28a737 (patch) | |
| tree | df999725a6f923928e6da3300054dfce1bff82de /tools/include/nolibc | |
| parent | 2ab446336b17aad362c6decee29b4efd83a01979 (diff) | |
| download | linux-539287d75178fd77c195520477dcd35a4d28a737.tar.xz | |
tools/nolibc: x86_64: shrink _start with _start_c
move most of the _start operations to _start_c(), include the
stackprotector initialization.
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Diffstat (limited to 'tools/include/nolibc')
| -rw-r--r-- | tools/include/nolibc/arch-x86_64.h | 29 |
1 files changed, 6 insertions, 23 deletions
diff --git a/tools/include/nolibc/arch-x86_64.h b/tools/include/nolibc/arch-x86_64.h index 6b494ca471ef..e5ccb926c903 100644 --- a/tools/include/nolibc/arch-x86_64.h +++ b/tools/include/nolibc/arch-x86_64.h @@ -8,6 +8,7 @@ #define _NOLIBC_ARCH_X86_64_H #include "compiler.h" +#include "crt.h" /* Syscalls for x86_64 : * - registers are 64-bit @@ -153,9 +154,6 @@ _ret; \ }) -char **environ __attribute__((weak)); -const unsigned long *_auxv __attribute__((weak)); - /* startup code */ /* * x86-64 System V ABI mandates: @@ -166,26 +164,11 @@ const unsigned long *_auxv __attribute__((weak)); void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void) { __asm__ volatile ( -#ifdef _NOLIBC_STACKPROTECTOR - "call __stack_chk_init\n" /* initialize stack protector */ -#endif - "pop %rdi\n" /* argc (first arg, %rdi) */ - "mov %rsp, %rsi\n" /* argv[] (second arg, %rsi) */ - "lea 8(%rsi,%rdi,8),%rdx\n" /* then a NULL then envp (third arg, %rdx) */ - "mov %rdx, environ\n" /* save environ */ - "xor %ebp, %ebp\n" /* zero the stack frame */ - "mov %rdx, %rax\n" /* search for auxv (follows NULL after last env) */ - "0:\n" - "add $8, %rax\n" /* search for auxv using rax, it follows the */ - "cmp -8(%rax), %rbp\n" /* ... NULL after last env (rbp is zero here) */ - "jnz 0b\n" - "mov %rax, _auxv\n" /* save it into _auxv */ - "and $-16, %rsp\n" /* x86 ABI : esp must be 16-byte aligned before call */ - "call main\n" /* main() returns the status code, we'll exit with it. */ - "mov %eax, %edi\n" /* retrieve exit code (32 bit) */ - "mov $60, %eax\n" /* NR_exit == 60 */ - "syscall\n" /* really exit */ - "hlt\n" /* ensure it does not return */ + "xor %ebp, %ebp\n" /* zero the stack frame */ + "mov %rsp, %rdi\n" /* save stack pointer to %rdi, as arg1 of _start_c */ + "and $-16, %rsp\n" /* %rsp must be 16-byte aligned before call */ + "call _start_c\n" /* transfer to c runtime */ + "hlt\n" /* ensure it does not return */ ); __builtin_unreachable(); } |