svn commit: r216780 - head/libexec/rtld-elf/powerpc64

[Nathan Whitehorn]

Author: nwhitehorn
Date: Tue Dec 28 22:31:59 2010
New Revision: 216780
URL: http://svn.freebsd.org/changeset/base/216780

Log:
  Fix an error in the ABI in rtld_bind_start(). When passing arguments to a
  C function, the caller's stack frame must have room to store all of the
  arguments to that function. While here, fix stack frame alignment issues.
  
  Without this change, the compiler will save r3 and r4 into the caller's
  stack frame before calling setjmp() in _rtld_bind(). These would then
  overwrite arguments to the newly-bound function, causing eventual failures.

Modified:
  head/libexec/rtld-elf/powerpc64/rtld_start.S

Modified: head/libexec/rtld-elf/powerpc64/rtld_start.S
==============================================================================
--- head/libexec/rtld-elf/powerpc64/rtld_start.S	Tue Dec 28 21:40:19 2010	(r216779)
+++ head/libexec/rtld-elf/powerpc64/rtld_start.S	Tue Dec 28 22:31:59 2010	(r216780)
@@ -35,15 +35,15 @@
 .extern _DYNAMIC
 
 _ENTRY(_rtld_start)
-	stdu    %r1,-96(%r1)	/* 16-byte aligned stack for reg saves +
+	stdu    %r1,-144(%r1)	/* 16-byte aligned stack for reg saves +
 				exit_proc & obj _rtld args +
 				backchain & lrsave stack frame */
-	std     %r3,48(%r1)	/*  argc */
-	std     %r4,56(%r1)	/*  argv */
-	std     %r5,64(%r1)	/*  envp */
-/*	std     %r6,72(%r1)   *//*  obj (always 0) */
-/*	std     %r7,80(%r1)   *//*  cleanup (always 0) */
-	std     %r8,88(%r1)	/*  ps_strings */
+	std     %r3,96(%r1)	/*  argc */
+	std     %r4,104(%r1)	/*  argv */
+	std     %r5,112(%r1)	/*  envp */
+/*	std     %r6,120(%r1)   *//*  obj (always 0) */
+/*	std     %r7,128(%r1)   *//*  cleanup (always 0) */
+	std     %r8,136(%r1)	/*  ps_strings */
 
 	/*
 	 * Perform initial relocation of ld-elf.so. Not as easy as it
@@ -75,10 +75,10 @@ _ENTRY(_rtld_start)
 	 * original stack layout has to be found by moving back a word
 	 * from the argv pointer.
 	 */
-	ld	%r4,56(%r1)
+	ld	%r4,104(%r1)
         addi    %r3,%r4,-8	/* locate argc ptr, &argv[-1] */
-	addi	%r4,%r1,80	/* &exit_proc on stack */
-	addi	%r5,%r1,72	/* &obj_main on stack */
+	addi	%r4,%r1,128	/* &exit_proc on stack */
+	addi	%r5,%r1,120	/* &obj_main on stack */
 
 	bl      ._rtld		/* &_start = _rtld(sp, &exit_proc, &obj_main)*/
 	nop
@@ -90,12 +90,12 @@ _ENTRY(_rtld_start)
 	/*
 	 * Restore args, with new obj/exit proc
 	 */
-	ld      %r3,48(%r1)     /* argc */
-	ld      %r4,56(%r1)	/* argv */
-	ld      %r5,64(%r1)	/* envp */
-	ld      %r6,72(%r1)	/* obj */
-	ld      %r7,80(%r1)	/* exit proc */
-	ld      %r8,88(%r1)	/* ps_strings */
+	ld      %r3,96(%r1)     /* argc */
+	ld      %r4,104(%r1)	/* argv */
+	ld      %r5,112(%r1)	/* envp */
+	ld      %r6,120(%r1)	/* obj */
+	ld      %r7,128(%r1)	/* exit proc */
+	ld      %r8,136(%r1)	/* ps_strings */
 
 	blrl	/* _start(argc, argv, envp, obj, cleanup, ps_strings) */
 
@@ -119,16 +119,17 @@ _ENTRY(_rtld_bind_start)
 	mfcr    %r0
 	std     %r0,8(%r1)		# save cr
 
-	stdu    %r1,-48-9*8(%r1)	# stack space for 8 regs + header
-	std	%r3,48+0*8(%r1)		# save r3-r31
-	std	%r4,48+1*8(%r1)
-	std	%r5,48+2*8(%r1)
-	std	%r6,48+3*8(%r1)
-	std	%r7,48+4*8(%r1)
-	std	%r8,48+5*8(%r1)
-	std	%r9,48+6*8(%r1)
-	std	%r10,48+7*8(%r1)
-	std	%r12,48+8*8(%r1)
+	stdu    %r1,-48-12*8(%r1)	# stack space for 8 regs + header
+					#   + 2 save regs
+	std	%r3,64+0*8(%r1)		# save r3-r31
+	std	%r4,64+1*8(%r1)
+	std	%r5,64+2*8(%r1)
+	std	%r6,64+3*8(%r1)
+	std	%r7,64+4*8(%r1)
+	std	%r8,64+5*8(%r1)
+	std	%r9,64+6*8(%r1)
+	std	%r10,64+7*8(%r1)
+	std	%r12,64+8*8(%r1)
 
 	ld	%r3,0(%r11)
 	ld	%r4,8(%r11)
@@ -140,22 +141,21 @@ _ENTRY(_rtld_bind_start)
 	ld	%r3,0(%r3)
 	mtctr   %r3			# move absolute target addr into ctr
 
-        ld	%r3,48+0*8(%r1)		# restore r3-r31
-        ld	%r4,48+1*8(%r1)
-        ld	%r5,48+2*8(%r1)
-        ld	%r6,48+3*8(%r1)
-	ld	%r7,48+4*8(%r1)
-	ld	%r8,48+5*8(%r1)
-	ld	%r9,48+6*8(%r1)
-	ld	%r10,48+7*8(%r1)
-	ld	%r12,48+8*8(%r1)
-
-        addi    %r1,%r1,48+9*8		# restore stack
-
-        ld	%r0,8(%r1)		# restore cr
-        mtcr    %r0
-        ld	%r0,16(%r1)		# restore lr
-        mtlr    %r0
+	ld	%r3,64+0*8(%r1)		# restore r3-r31
+	ld	%r4,64+1*8(%r1)
+	ld	%r5,64+2*8(%r1)
+	ld	%r6,64+3*8(%r1)
+	ld	%r7,64+4*8(%r1)
+	ld	%r8,64+5*8(%r1)
+	ld	%r9,64+6*8(%r1)
+	ld	%r10,64+7*8(%r1)
+	ld	%r12,64+8*8(%r1)
+
+	ld	%r1,0(%r1)		# restore stack
+	ld	%r0,8(%r1)		# restore cr
+	mtcr    %r0
+	ld	%r0,16(%r1)		# restore lr
+	mtlr    %r0
 
-        bctr				# jump to target
+	bctr				# jump to target