Messages in this thread | | | Date | Wed, 3 Mar 2010 23:02:52 +0100 | From | Frederic Weisbecker <> | Subject | Re: [RFC][PATCH 07/11] perf: Provide PERF_SAMPLE_REGS |
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On Wed, Mar 03, 2010 at 05:39:43PM +0100, Peter Zijlstra wrote: > Simply copy out the provided pt_regs in a u64 aligned fashion. > > XXX: do task_pt_regs() and get_irq_regs() always clear everything or > are we now leaking data?
It looks like there is a leak in case of non trace syscalls. where we don't appear to save r12-15.
Then task_pt_regs() may leak the top of a process stack...?
> > Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> > --- > include/linux/perf_event.h | 5 ++++- > kernel/perf_event.c | 17 +++++++++++++++++ > 2 files changed, 21 insertions(+), 1 deletion(-) > > Index: linux-2.6/include/linux/perf_event.h > =================================================================== > --- linux-2.6.orig/include/linux/perf_event.h > +++ linux-2.6/include/linux/perf_event.h > @@ -125,8 +125,9 @@ enum perf_event_sample_format { > PERF_SAMPLE_PERIOD = 1U << 8, > PERF_SAMPLE_STREAM_ID = 1U << 9, > PERF_SAMPLE_RAW = 1U << 10, > + PERF_SAMPLE_REGS = 1U << 11, > > - PERF_SAMPLE_MAX = 1U << 11, /* non-ABI */ > + PERF_SAMPLE_MAX = 1U << 12, /* non-ABI */ > }; > > /* > @@ -392,6 +393,7 @@ enum perf_event_type { > * { u64 period; } && PERF_SAMPLE_PERIOD > * > * { struct read_format values; } && PERF_SAMPLE_READ > + * { struct pt_regs regs; } && PERF_SAMPLE_REGS > * > * { u64 nr, > * u64 ips[nr]; } && PERF_SAMPLE_CALLCHAIN > @@ -800,6 +802,7 @@ struct perf_sample_data { > u64 period; > struct perf_callchain_entry *callchain; > struct perf_raw_record *raw; > + struct pt_regs *regs; > }; > > static inline > Index: linux-2.6/kernel/perf_event.c > =================================================================== > --- linux-2.6.orig/kernel/perf_event.c > +++ linux-2.6/kernel/perf_event.c > @@ -3176,6 +3176,17 @@ void perf_output_sample(struct perf_outp > if (sample_type & PERF_SAMPLE_READ) > perf_output_read(handle, event); > > + if (sample_type & PERF_SAMPLE_REGS) { > + int size = DIV_ROUND_UP(sizeof(struct pt_regs), sizeof(u64)) - > + sizeof(struct pt_regs); > + > + perf_output_put(handle, *data->regs); > + if (size) { > + u64 zero = 0; > + perf_output_copy(handle, &zero, size); > + } > + } > + > if (sample_type & PERF_SAMPLE_CALLCHAIN) { > if (data->callchain) { > int size = 1; > @@ -3273,6 +3284,12 @@ void perf_prepare_sample(struct perf_eve > if (sample_type & PERF_SAMPLE_READ) > header->size += perf_event_read_size(event); > > + if (sample_type & PERF_SAMPLE_REGS) { > + data->regs = regs; > + header->size += DIV_ROUND_UP(sizeof(struct pt_regs), > + sizeof(u64)); > + } > + > if (sample_type & PERF_SAMPLE_CALLCHAIN) { > int size = 1; > > > -- >
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