perf: Add ability to attach user stack dump to sample

Introducing PERF_SAMPLE_STACK_USER sample type bit to trigger the dump
of the user level stack on sample. The size of the dump is specified by
sample_stack_user value.

Being able to dump parts of the user stack, starting from the stack
pointer, will be useful to make a post mortem dwarf CFI based stack
unwinding.

Added HAVE_PERF_USER_STACK_DUMP config option to determine if the
architecture provides user stack dump on perf event samples.  This needs
access to the user stack pointer which is not unified across
architectures. Enabling this for x86 architecture.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Original-patch-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Arun Sharma <asharma@fb.com>
Cc: Benjamin Redelings <benjamin.redelings@nescent.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Ulrich Drepper <drepper@gmail.com>
Link: http://lkml.kernel.org/r/1344345647-11536-6-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 8a73f75beb16..d1d25f6a5e24 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -131,8 +131,9 @@ enum perf_event_sample_format {
         PERF_SAMPLE_RAW                         = 1U << 10,
         PERF_SAMPLE_BRANCH_STACK                = 1U << 11,
         PERF_SAMPLE_REGS_USER                   = 1U << 12,
+        PERF_SAMPLE_STACK_USER                  = 1U << 13,
 
-        PERF_SAMPLE_MAX = 1U << 13,             /* non-ABI */
+        PERF_SAMPLE_MAX = 1U << 14,             /* non-ABI */
 };
 
 /*
@@ -205,6 +206,7 @@ enum perf_event_read_format {
 #define PERF_ATTR_SIZE_VER1     72      /* add: config2 */
 #define PERF_ATTR_SIZE_VER2     80      /* add: branch_sample_type */
 #define PERF_ATTR_SIZE_VER3     88      /* add: sample_regs_user */
+#define PERF_ATTR_SIZE_VER4     96      /* add: sample_stack_user */
 
 /*
  * Hardware event_id to monitor via a performance monitoring event:
@@ -289,6 +291,14 @@ struct perf_event_attr {
          * See asm/perf_regs.h for details.
          */
         __u64   sample_regs_user;
+
+        /*
+         * Defines size of the user stack to dump on samples.
+         */
+        __u32   sample_stack_user;
+
+        /* Align to u64. */
+        __u32   __reserved_2;
 };
 
 /*
@@ -568,6 +578,10 @@ enum perf_event_type {
          *
          *      { u64                   abi; # enum perf_sample_regs_abi
          *        u64                   regs[weight(mask)]; } && PERF_SAMPLE_REGS_USER
+         *
+         *      { u64                   size;
+         *        char                  data[size];
+         *        u64                   dyn_size; } && PERF_SAMPLE_STACK_USER
          * };
          */
         PERF_RECORD_SAMPLE                      = 9,
@@ -1160,6 +1174,7 @@ struct perf_sample_data {
         struct perf_raw_record          *raw;
         struct perf_branch_stack        *br_stack;
         struct perf_regs_user           regs_user;
+        u64                             stack_user_size;
 };
 
 static inline void perf_sample_data_init(struct perf_sample_data *data,
@@ -1172,6 +1187,7 @@ static inline void perf_sample_data_init(struct perf_sample_data *data,
         data->period = period;
         data->regs_user.abi = PERF_SAMPLE_REGS_ABI_NONE;
         data->regs_user.regs = NULL;
+        data->stack_user_size = 0;
 }
 
 extern void perf_output_sample(struct perf_output_handle *handle,