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tools/nolibc: aarch64: shrink _start with _start_c

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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>
This commit is contained in:
Zhangjin Wu 2023-07-16 02:25:35 +08:00 committed by Willy Tarreau
parent 61f9880721
commit ded8af47c2
1 changed files with 4 additions and 23 deletions
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27
tools/include/nolibc/arch-aarch64.h
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@ -8,6 +8,7 @@
#define _NOLIBC_ARCH_AARCH64_H
#include "compiler.h"
#include "crt.h"
/* Syscalls for AARCH64 :
* - registers are 64-bit
@ -143,33 +144,13 @@
_arg1; \
})
char **environ __attribute__((weak));
const unsigned long *_auxv __attribute__((weak));
/* startup code */
void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
{
__asm__ volatile (
#ifdef _NOLIBC_STACKPROTECTOR
"bl __stack_chk_init\n" /* initialize stack protector */
#endif
"ldr x0, [sp]\n" /* argc (x0) was in the stack */
"add x1, sp, 8\n" /* argv (x1) = sp */
"lsl x2, x0, 3\n" /* envp (x2) = 8*argc ... */
"add x2, x2, 8\n" /* + 8 (skip null) */
"add x2, x2, x1\n" /* + argv */
"adrp x3, environ\n" /* x3 = &environ (high bits) */
"str x2, [x3, #:lo12:environ]\n" /* store envp into environ */
"mov x4, x2\n" /* search for auxv (follows NULL after last env) */
"0:\n"
"ldr x5, [x4], 8\n" /* x5 = *x4; x4 += 8 */
"cbnz x5, 0b\n" /* and stop at NULL after last env */
"adrp x3, _auxv\n" /* x3 = &_auxv (high bits) */
"str x4, [x3, #:lo12:_auxv]\n" /* store x4 into _auxv */
"and sp, x1, -16\n" /* sp must be 16-byte aligned in the callee */
"bl main\n" /* main() returns the status code, we'll exit with it. */
"mov x8, 93\n" /* NR_exit == 93 */
"svc #0\n"
"mov x0, sp\n" /* save stack pointer to x0, as arg1 of _start_c */
"and sp, x0, -16\n" /* sp must be 16-byte aligned in the callee */
"bl _start_c\n" /* transfer to c runtime */
);
__builtin_unreachable();
}