Commit c48d8af2 authored by Zhangjin Wu's avatar Zhangjin Wu Committed by Willy Tarreau
Browse files

tools/nolibc: s390: shrink _start with _start_c 



move most of the _start operations to _start_c(), include the
stackprotector initialization.

Signed-off-by: default avatarZhangjin Wu <falcon@tinylab.org>
Signed-off-by: default avatarWilly Tarreau <w@1wt.eu>
parent eea70cda

tools/include/nolibc/arch-s390.h

+5 −31
Original line number Diff line number Diff line
@@ -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"



		"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,main\n"		/* ret value of main is arg to exit */

		"lghi	%r1,1\n"		/* __NR_exit */

		"svc	0\n"

		"brasl	%r14, _start_c\n"     /* transfer to c runtime                          */

	);

	__builtin_unreachable();

}