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Tweak sparc32 longjmp to not store a dummy frame pointer onto the stack.

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* sysdeps/sparc/sparc32/__longjmp.S: Unwind in the 'thread' path
	using a normal save/restore sequence, rather than allocating a
	dummy stack frame just to store a frame pointer and restore.
	* sysdeps/unix/sysv/linux/sparc/sparc32/____longjmp_chk.S: Likewise.
This commit is contained in:
David S. Miller
2012-02-20 20:50:14 -08:00
parent fb06851d67
commit c0e70b2543
3 changed files with 15 additions and 12 deletions
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10
sysdeps/sparc/sparc32/__longjmp.S
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@@ -21,7 +21,6 @@
#include <jmpbuf-offsets.h>
#define ENV(base,reg) [%base + (reg * 4)]
#define ST_FLUSH_WINDOWS 3
#define RW_FP [%fp + 0x48]
ENTRY(__longjmp)
/* Store our arguments in global registers so we can still
@@ -54,6 +53,7 @@ LOC(loop):
ld ENV(g1,JB_SP), %o0 /* Delay slot: extract target SP. */
LOC(thread):
save %sp, -96, %sp
/*
* Do a "flush register windows trap". The trap handler in the
* kernel writes all the register windows to their stack slots, and
@@ -66,15 +66,13 @@ LOC(thread):
#ifdef PTR_DEMANGLE
ld ENV(g1,JB_PC), %g5 /* Set return PC. */
ld ENV(g1,JB_SP), %g1 /* Set saved SP on restore below. */
PTR_DEMANGLE2 (%o7, %g5, %g4)
PTR_DEMANGLE2 (%i7, %g5, %g4)
PTR_DEMANGLE2 (%fp, %g1, %g4)
#else
ld ENV(g1,JB_PC), %o7 /* Set return PC. */
ld ENV(g1,JB_PC), %i7 /* Set return PC. */
ld ENV(g1,JB_SP), %fp /* Set saved SP on restore below. */
#endif
sub %fp, 64, %sp /* Allocate a register frame. */
st %g3, RW_FP /* Set saved FP on restore below. */
retl
jmp %i7 + 8
restore %g2, 0, %o0 /* Restore values from above register frame. */
LOC(found):