On Wed, Dec 17, 2014 at 04:45:07PM +0100, Jiri Olsa wrote: > On Wed, Dec 17, 2014 at 04:35:08PM +0100, Peter Zijlstra wrote: > > On Wed, Dec 17, 2014 at 03:31:05PM +0100, Jiri Olsa wrote: > > > looks like we could also sanitize the perf_ftrace_function_call > > > in the same way.. like below (untested) > > > > > > hum, I just noticed it actually has pt_regs arg ;-) > > > > Bu if it has pt_regs should we not use that instead of filling one out > > again? > > yep, I talked to Steven about that and the thing is that > it's not guaranteed on all archs.. I'll send patch that > take that in account
and here it is.. jirka --- Fixing the perf function tracer pt_regs retrieval in a similar way as started by Peter in following patch: http://marc.info/?t=141873073100002&r=1&w=2 The only change for perf function tracer is that we can register 'struct ftrace_ops' with SAVE_REGS_IF_SUPPORTED flag, which forces ftrace to fill in data for pt_regs callback argument. In case we don't get pt_regs data (some architectures might not have support this), we follow the regs retrieval way introduced by Peter in above patch. Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra (Intel) <[email protected]> Cc: Steven Rostedt <[email protected]> Signed-off-by: Jiri Olsa <[email protected]> --- kernel/trace/trace_event_perf.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index 6fa484de2ba1..54bffedd28b6 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -304,7 +304,7 @@ perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip, { struct ftrace_entry *entry; struct hlist_head *head; - struct pt_regs regs; + struct pt_regs **regsp, *regs = pt_regs; int rctx; head = this_cpu_ptr(event_function.perf_events); @@ -316,16 +316,24 @@ perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip, BUILD_BUG_ON(ENTRY_SIZE > PERF_MAX_TRACE_SIZE); - perf_fetch_caller_regs(®s); + /* + * The ftrace_ops is registered with SAVE_REGS_IF_SUPPORTED, + * so if we got pt_regs defined, we don't need to retrieve + * regs buffer through perf_trace_buf_prepare. + */ + regsp = pt_regs ? NULL : ®s; - entry = perf_trace_buf_prepare(ENTRY_SIZE, TRACE_FN, NULL, &rctx); + entry = perf_trace_buf_prepare(ENTRY_SIZE, TRACE_FN, regsp, &rctx); if (!entry) return; + if (regsp) + perf_fetch_caller_regs(regs); + entry->ip = ip; entry->parent_ip = parent_ip; perf_trace_buf_submit(entry, ENTRY_SIZE, rctx, 0, - 1, ®s, head, NULL); + 1, regs, head, NULL); #undef ENTRY_SIZE } @@ -334,7 +342,7 @@ static int perf_ftrace_function_register(struct perf_event *event) { struct ftrace_ops *ops = &event->ftrace_ops; - ops->flags |= FTRACE_OPS_FL_CONTROL; + ops->flags |= FTRACE_OPS_FL_CONTROL|FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED; ops->func = perf_ftrace_function_call; return register_ftrace_function(ops); } -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
