[tip:perf/core] perf, trace: Fix !x86 build bug

tip-bot for Peter Zijlstra
2010-05-25T09:31:30Z

Commit-ID: 87f44bbc246c5244c76a701f8eefba7788bce64a
Gitweb: http://git.kernel.org/tip/87f44bbc246c5244c76a701f8eefba7788bce64a
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Tue, 25 May 2010 11:02:55 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 25 May 2010 11:28:49 +0200

perf, trace: Fix !x86 build bug

Patch b7e2ecef92 (perf, trace: Optimize tracepoints by removing
IRQ-disable from perf/tracepoint interaction) made the
unfortunate mistake of assuming the world is x86 only, correct
this.

The problem was that perf_fetch_caller_regs() did
local_save_flags() into regs->flags, and I re-used that to
remove another local_save_flags(), forgetting !x86 doesn't have
regs->flags.

Do the reverse, remove the local_save_flags() from
perf_fetch_caller_regs() and let the ftrace site do the
local_save_flags() instead.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Mackerras <paulus@samba.org>
Cc: acme@redhat.com
Cc: efault@gmx.de
Cc: fweisbec@gmail.com
Cc: rostedt@goodmis.org
LKML-Reference: <1274778175.5882.623.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/kernel/cpu/perf_event.c | 6 +++++-
kernel/trace/trace_event_perf.c | 4 +++-
2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index fd4db0d..c775860 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1717,7 +1717,11 @@ void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int ski
*/
regs->bp = rewind_frame_pointer(skip + 1);
regs->cs = __KERNEL_CS;
- local_save_flags(regs->flags);
+ /*
+ * We abuse bit 3 to pass exact information, see perf_misc_flags
+ * and the comment with PERF_EFLAGS_EXACT.
+ */
+ regs->flags = 0;
}

unsigned long perf_instruction_pointer(struct pt_regs *regs)
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 26b8607..cb6f365 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -157,6 +157,7 @@ __kprobes void *perf_trace_buf_prepare(int size, unsigned short type,
struct pt_regs *regs, int *rctxp)
{
struct trace_entry *entry;
+ unsigned long flags;
char *raw_data;
int pc;

@@ -174,7 +175,8 @@ __kprobes void *perf_trace_buf_prepare(int size, unsigned short type,
memset(&raw_data[size - sizeof(u64)], 0, sizeof(u64));

entry = (struct trace_entry *)raw_data;
- tracing_generic_entry_update(entry, regs->flags, pc);
+ local_save_flags(flags);
+ tracing_generic_entry_update(entry, flags, pc);
entry->type = type;

return raw_data;