[PATCH V6 03/16] perf/core: Add support for PERF_SAMPLE_CODE_PAGE_SIZE

Kan Liang
2020-08-10T21:28:37Z

From: Stephane Eranian <eranian@google.com>

When studying code layout, it is useful to capture the page size of the
sampled code address.

Add a new sample type for code page size.
The new sample type requires collecting the ip. The code page size can
be calculated from the IRQ-safe perf_get_page_size().

Only the generic support is covered. The large PEBS will be disabled
with this sample type.

Signed-off-by: Stephane Eranian <eranian@google.com>
---
include/linux/perf_event.h | 1 +
include/uapi/linux/perf_event.h | 4 +++-
kernel/events/core.c | 11 ++++++++++-
3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 5de95f36d7a8..f3d5ca63d831 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1036,6 +1036,7 @@ struct perf_sample_data {
u64 phys_addr;
u64 cgroup;
u64 data_page_size;
+ u64 code_page_size;
} ____cacheline_aligned;

/* default value for data source */
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 32484accc7a3..01c73860da48 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -144,8 +144,9 @@ enum perf_event_sample_format {
PERF_SAMPLE_AUX = 1U << 20,
PERF_SAMPLE_CGROUP = 1U << 21,
PERF_SAMPLE_DATA_PAGE_SIZE = 1U << 22,
+ PERF_SAMPLE_CODE_PAGE_SIZE = 1U << 23,

- PERF_SAMPLE_MAX = 1U << 23, /* non-ABI */
+ PERF_SAMPLE_MAX = 1U << 24, /* non-ABI */

__PERF_SAMPLE_CALLCHAIN_EARLY = 1ULL << 63, /* non-ABI; internal use */
};
@@ -881,6 +882,7 @@ enum perf_event_type {
* { u64 size;
* char data[size]; } && PERF_SAMPLE_AUX
* { u64 data_page_size;} && PERF_SAMPLE_DATA_PAGE_SIZE
+ * { u64 code_page_size;} && PERF_SAMPLE_CODE_PAGE_SIZE
* };
*/
PERF_RECORD_SAMPLE = 9,
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 00becacfd15e..6bfd7fd16d06 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1899,6 +1899,9 @@ static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
size += sizeof(data->data_page_size);

+ if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
+ size += sizeof(data->code_page_size);
+
event->header_size = size;
}

@@ -6946,6 +6949,9 @@ void perf_output_sample(struct perf_output_handle *handle,
if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
perf_output_put(handle, data->data_page_size);

+ if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
+ perf_output_put(handle, data->code_page_size);
+
if (sample_type & PERF_SAMPLE_AUX) {
perf_output_put(handle, data->aux_size);

@@ -7149,7 +7155,7 @@ void perf_prepare_sample(struct perf_event_header *header,

__perf_event_header__init_id(header, data, event);

- if (sample_type & PERF_SAMPLE_IP)
+ if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE))
data->ip = perf_instruction_pointer(regs);

if (sample_type & PERF_SAMPLE_CALLCHAIN) {
@@ -7272,6 +7278,9 @@ void perf_prepare_sample(struct perf_event_header *header,
if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
data->data_page_size = perf_get_page_size(data->addr);

+ if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
+ data->code_page_size = perf_get_page_size(data->ip);
+
if (sample_type & PERF_SAMPLE_AUX) {
u64 size;

--
2.17.1