[RFC][PATCH 07/11] perf: Provide PERF_SAMPLE_REGS

Peter Zijlstra
2010-03-03T16:49:31Z

[-- Attachment #1: perf-sample-regs.patch --]
[-- Type: text/plain, Size: 2365 bytes --]

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?

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;

--