svn commit: r231930 - projects/arm_eabi/libexec/rtld-elf/arm

[Andrew Turner]

Author: andrew
Date: Mon Feb 20 08:56:10 2012
New Revision: 231930
URL: http://svn.freebsd.org/changeset/base/231930

Log:
  Correctly align the stack before calling into C code.
  
  We restore the stack before jumping to the entry point as _start needs the
  stack in the same state as we were given it and also fixes the stack to be
  correctly aligned.

Modified:
  projects/arm_eabi/libexec/rtld-elf/arm/rtld_start.S

Modified: projects/arm_eabi/libexec/rtld-elf/arm/rtld_start.S
==============================================================================
--- projects/arm_eabi/libexec/rtld-elf/arm/rtld_start.S	Mon Feb 20 06:35:52 2012	(r231929)
+++ projects/arm_eabi/libexec/rtld-elf/arm/rtld_start.S	Mon Feb 20 08:56:10 2012	(r231930)
@@ -37,6 +37,8 @@ __FBSDID("$FreeBSD$");
 	.globl	.rtld_start
 	.type	.rtld_start,%function
 .rtld_start:
+	mov	r6, sp			/* save the stack pointer */
+	bic	sp, sp, #7
 	sub	sp, sp, #8		/* make room for obj_main & exit proc */
 	mov	r4, r0			/* save ps_strings */
 	ldr	sl, .L2
@@ -52,13 +54,13 @@ __FBSDID("$FreeBSD$");
 	bl	_rtld_relocate_nonplt_self
 	mov	r1, sp
 	add	r2, sp, #4
-	add	r0, sp, #8
+	mov	r0, r6			/* load the sp the kernel gave us */
 	bl	_rtld			/* call the shared loader */
 	mov	r3, r0			/* save entry point */
 
 	ldr	r2, [sp, #0]		/* r2 = cleanup */
 	ldr	r1, [sp, #4]		/* r1 = obj_main */
-	add	sp, sp, #8		/* restore stack */
+	mov	sp, r6			/* restore stack */
 	mov	r0, r4			/* restore ps_strings */
 	mov	pc, r3			/* jump to the entry point */
 .L2: