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Fix an error in the ABI in rtld_bind_start(). When passing arguments to a

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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.
This commit is contained in:
Nathan Whitehorn 2010-12-28 22:31:59 +00:00
parent acd7984f96
commit 071a51cf97
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=216780
1 changed files with 42 additions and 42 deletions
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84
libexec/rtld-elf/powerpc64/rtld_start.S
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@ -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)
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)
addi %r1,%r1,48+9*8 # restore stack
ld %r1,0(%r1) # restore stack
ld %r0,8(%r1) # restore cr
mtcr %r0
ld %r0,16(%r1) # restore lr
mtlr %r0
ld %r0,8(%r1) # restore cr
mtcr %r0
ld %r0,16(%r1) # restore lr
mtlr %r0
bctr # jump to target
bctr # jump to target