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authorSoeren Sandmann Pedersen <sandmann@redhat.com>2010-11-05 05:59:39 -0400
committerFrederic Weisbecker <fweisbec@gmail.com>2010-11-18 14:37:34 +0100
commit9c0729dc8062bed96189bd14ac6d4920f3958743 (patch)
treeea124a706d49b52e04257df13f3aeb980d6000cd /arch/x86/oprofile
parent3985c7ce85039adacdf882904ca096f091d39346 (diff)
downloadlinux-9c0729dc8062bed96189bd14ac6d4920f3958743.tar.bz2
x86: Eliminate bp argument from the stack tracing routines
The various stack tracing routines take a 'bp' argument in which the caller is supposed to provide the base pointer to use, or 0 if doesn't have one. Since bp is garbage whenever CONFIG_FRAME_POINTER is not defined, this means all callers in principle should either always pass 0, or be conditional on CONFIG_FRAME_POINTER. However, there are only really three use cases for stack tracing: (a) Trace the current task, including IRQ stack if any (b) Trace the current task, but skip IRQ stack (c) Trace some other task In all cases, if CONFIG_FRAME_POINTER is not defined, bp should just be 0. If it _is_ defined, then - in case (a) bp should be gotten directly from the CPU's register, so the caller should pass NULL for regs, - in case (b) the caller should should pass the IRQ registers to dump_trace(), - in case (c) bp should be gotten from the top of the task's stack, so the caller should pass NULL for regs. Hence, the bp argument is not necessary because the combination of task and regs is sufficient to determine an appropriate value for bp. This patch introduces a new inline function stack_frame(task, regs) that computes the desired bp. This function is then called from the two versions of dump_stack(). Signed-off-by: Soren Sandmann <ssp@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arjan van de Ven <arjan@infradead.org>, Cc: Frederic Weisbecker <fweisbec@gmail.com>, Cc: Arnaldo Carvalho de Melo <acme@redhat.com>, LKML-Reference: <m3oc9rop28.fsf@dhcp-100-3-82.bos.redhat.com>> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Diffstat (limited to 'arch/x86/oprofile')
-rw-r--r--arch/x86/oprofile/backtrace.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/oprofile/backtrace.c b/arch/x86/oprofile/backtrace.c
index 2d49d4e19a36..72cbec14d783 100644
--- a/arch/x86/oprofile/backtrace.c
+++ b/arch/x86/oprofile/backtrace.c
@@ -126,7 +126,7 @@ x86_backtrace(struct pt_regs * const regs, unsigned int depth)
if (!user_mode_vm(regs)) {
unsigned long stack = kernel_stack_pointer(regs);
if (depth)
- dump_trace(NULL, regs, (unsigned long *)stack, 0,
+ dump_trace(NULL, regs, (unsigned long *)stack,
&backtrace_ops, &depth);
return;
}