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authorDaniel Jacobowitz <drow@false.org>2006-08-30 15:02:08 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2006-09-20 14:58:35 +0100
commit6a39dd6222dda5ee2414a1b42e8e62118742a49e (patch)
tree8c4eeeb2d48b583aed900f2a3e8c57f0536a0193 /arch/arm/kernel
parent681a4991f83742a0d2325afbf7b7f22045ad5b30 (diff)
[ARM] 3759/2: Remove uses of %?
Patch from Daniel Jacobowitz The ARM kernel has several uses of asm("foo%?"). %? is a GCC internal modifier used to output conditional execution predicates. However, no version of GCC supports conditionalizing asm statements. GCC 4.2 will correctly expand %? to the empty string in user asms. Earlier versions may reuse the condition from the previous instruction. In 'if (foo) asm ("bar%?");' this is somewhat likely to be right... but not reliable. So, the only safe thing to do is to remove the uses of %?. I believe the tlbflush.h occurances were supposed to be removed before, based on the comment about %? not working at the top of that file. Old versions of GCC could omit branches around user asms if the asm didn't mark the condition codes as clobbered. This problem hasn't been seen on any recent (3.x or 4.x) GCC, but it could theoretically happen. So, where %? was removed a cc clobber was added. Signed-off-by: Daniel Jacobowitz <dan@codesourcery.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel')
-rw-r--r--arch/arm/kernel/traps.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index aeeed806f99..bede380c07a 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -191,7 +191,7 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
if (tsk != current)
fp = thread_saved_fp(tsk);
else
- asm("mov%? %0, fp" : "=r" (fp));
+ asm("mov %0, fp" : "=r" (fp) : : "cc");
c_backtrace(fp, 0x10);
barrier();