tools/nolibc: arm: 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>

diff --git a/tools/include/nolibc/arch-arm.h b/tools/include/nolibc/arch-arm.h
index a06dad7..cae4afa 100644 (file)
--- a/tools/include/nolibc/arch-arm.h
+++ b/tools/include/nolibc/arch-arm.h
@@ -8,6 +8,7 @@
 #define _NOLIBC_ARCH_ARM_H
 
 #include "compiler.h"
+#include "crt.h"
 
 /* Syscalls for ARM in ARM or Thumb modes :
  *   - registers are 32-bit
@@ -183,49 +184,14 @@
        _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
-               "pop {%r0}\n"                 /* argc was in the stack                               */
-               "mov %r1, %sp\n"              /* argv = sp                                           */
-
-               "add %r2, %r0, $1\n"          /* envp = (argc + 1) ...                               */
-               "lsl %r2, %r2, $2\n"          /*        * 4        ...                               */
-               "add %r2, %r2, %r1\n"         /*        + argv                                       */
-               "ldr %r3, 1f\n"               /* r3 = &environ (see below)                           */
-               "str %r2, [r3]\n"             /* store envp into environ                             */
-
-               "mov r4, r2\n"                /* search for auxv (follows NULL after last env)       */
-               "0:\n"
-               "mov r5, r4\n"                /* r5 = r4                                             */
-               "add r4, r4, #4\n"            /* r4 += 4                                             */
-               "ldr r5,[r5]\n"               /* r5 = *r5 = *(r4-4)                                  */
-               "cmp r5, #0\n"                /* and stop at NULL after last env                     */
-               "bne 0b\n"
-               "ldr %r3, 2f\n"               /* r3 = &_auxv (low bits)                              */
-               "str r4, [r3]\n"              /* store r4 into _auxv                                 */
-
-               "mov %r3, $8\n"               /* AAPCS : sp must be 8-byte aligned in the            */
-               "neg %r3, %r3\n"              /*         callee, and bl doesn't push (lr=pc)         */
-               "and %r3, %r3, %r1\n"         /* so we do sp = r1(=sp) & r3(=-8);                    */
-               "mov %sp, %r3\n"
-
-               "bl main\n"                   /* main() returns the status code, we'll exit with it. */
-               "movs r7, $1\n"               /* NR_exit == 1                                        */
-               "svc $0x00\n"
-               ".align 2\n"                  /* below are the pointers to a few variables           */
-               "1:\n"
-               ".word environ\n"
-               "2:\n"
-               ".word _auxv\n"
+               "mov %r0, sp\n"         /* save stack pointer to %r0, as arg1 of _start_c */
+               "and ip, %r0, #-8\n"    /* sp must be 8-byte aligned in the callee        */
+               "mov sp, ip\n"
+               "bl  _start_c\n"        /* transfer to c runtime                          */
        );
        __builtin_unreachable();
 }