tools/nolibc: s390: 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-s390.h b/tools/include/nolibc/arch-s390.h
index 3b94ae0cb1d1bedb42ed704fe205446b867987ac..5d60fd43f88309e099aa07efc6369fa8ab7e2a60 100644 (file)
--- a/tools/include/nolibc/arch-s390.h
+++ b/tools/include/nolibc/arch-s390.h
@@ -9,6 +9,7 @@
 #include <asm/unistd.h>
 
 #include "compiler.h"
+#include "crt.h"
 
 /* Syscalls for s390:
  *   - registers are 64-bit
@@ -137,41 +138,14 @@
        _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 (
-               "lg     %r2,0(%r15)\n"          /* argument count */
-               "la     %r3,8(%r15)\n"          /* argument pointers */
-
-               "xgr    %r0,%r0\n"              /* r0 will be our NULL value */
-               /* search for envp */
-               "lgr    %r4,%r3\n"              /* start at argv */
-               "0:\n"
-               "clg    %r0,0(%r4)\n"           /* entry zero? */
-               "la     %r4,8(%r4)\n"           /* advance pointer */
-               "jnz    0b\n"                   /* no -> test next pointer */
-                                               /* yes -> r4 now contains start of envp */
-               "larl   %r1,environ\n"
-               "stg    %r4,0(%r1)\n"
-
-               /* search for auxv */
-               "lgr    %r5,%r4\n"              /* start at envp */
-               "1:\n"
-               "clg    %r0,0(%r5)\n"           /* entry zero? */
-               "la     %r5,8(%r5)\n"           /* advance pointer */
-               "jnz    1b\n"                   /* no -> test next pointer */
-               "larl   %r1,_auxv\n"            /* yes -> store value in _auxv */
-               "stg    %r5,0(%r1)\n"
-
-               "aghi   %r15,-160\n"            /* allocate new stackframe */
-               "xc     0(8,%r15),0(%r15)\n"    /* clear backchain */
-               "brasl  %r14,main\n"            /* ret value of main is arg to exit */
-               "lghi   %r1,1\n"                /* __NR_exit */
-               "svc    0\n"
+               "lgr    %r2, %r15\n"          /* save stack pointer to %r2, as arg1 of _start_c */
+               "aghi   %r15, -160\n"         /* allocate new stackframe                        */
+               "xc     0(8,%r15), 0(%r15)\n" /* clear backchain                                */
+               "brasl  %r14, _start_c\n"     /* transfer to c runtime                          */
        );
        __builtin_unreachable();
 }