perf/core: Add support for PERF_SAMPLE_CODE_PAGE_SIZE

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 NMI-safe perf_get_page_size().

For large PEBS, it's very unlikely that the mapping is gone for the
earlier PEBS records. Enable the feature for the large PEBS. The worst
case is that page-size '0' is returned.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201001135749.2804-5-kan.liang@linux.intel.com

diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index ee2b9b9fc2a50e3e63c93bf8f4bd7d13acbf9c60..10032f023fcc298acd76d889d767ff0fc873a590 100644 (file)
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -132,7 +132,7 @@ struct amd_nb {
        PERF_SAMPLE_DATA_SRC | PERF_SAMPLE_IDENTIFIER | \
        PERF_SAMPLE_TRANSACTION | PERF_SAMPLE_PHYS_ADDR | \
        PERF_SAMPLE_REGS_INTR | PERF_SAMPLE_REGS_USER | \
-       PERF_SAMPLE_PERIOD)
+       PERF_SAMPLE_PERIOD | PERF_SAMPLE_CODE_PAGE_SIZE)
 
 #define PEBS_GP_REGS                   \
        ((1ULL << PERF_REG_X86_AX)    | \

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 7e3785dd27d93582b63456a5e8cf8698bac8ae4f..e533b03af053a3d5d01257bfa5e7c2788eee4cce 100644 (file)
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1035,6 +1035,7 @@ 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 cc6ea346e9f997ac69207926cd75efc804a6a3e2..c2f20ee3124d583a9f163704fed318d608510efa 100644 (file)
--- 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 */
 };
@@ -898,6 +899,7 @@ 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 a796db2f3b57978f5b04a44509c4328cd8cec6a2..7f655d19b8c40da6d93fe143dfa12913b11ffcc7 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1898,6 +1898,9 @@ 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;
 }
 
@@ -6945,6 +6948,9 @@ 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);
 
@@ -7125,7 +7131,7 @@ 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) {
@@ -7253,6 +7259,9 @@ 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;