From 6a39dd6222dda5ee2414a1b42e8e62118742a49e Mon Sep 17 00:00:00 2001 From: Daniel Jacobowitz Date: Wed, 30 Aug 2006 15:02:08 +0100 Subject: [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 Signed-off-by: Russell King --- arch/arm/kernel/traps.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arm/kernel') diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index aeeed806f991..bede380c07a9 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(); -- cgit v1.2.3