lkml.org 
[lkml]   [2023]   [Jul]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v4 08/18] tools/nolibc: aarch64: shrink _start with _start_c
    Date
    move most of the _start operations to _start_c(), include the
    stackprotector initialization.

    Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
    ---
    tools/include/nolibc/arch-aarch64.h | 27 ++++-----------------------
    1 file changed, 4 insertions(+), 23 deletions(-)

    diff --git a/tools/include/nolibc/arch-aarch64.h b/tools/include/nolibc/arch-aarch64.h
    index 3c0a5f47b3e8..6c33c46848e3 100644
    --- a/tools/include/nolibc/arch-aarch64.h
    +++ b/tools/include/nolibc/arch-aarch64.h
    @@ -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();
    }
    --
    2.25.1
    \
     
     \ /
      Last update: 2023-07-16 20:53    [W:8.352 / U:0.220 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site