perf: Add ability to sample machine state on interrupt

Enable capture of interrupted machine state for each sample.

Registers to sample are passed per event in the sample_regs_intr bitmask.

To sample interrupt machine state, the PERF_SAMPLE_INTR_REGS must be passed in
sample_type.

The list of available registers is arch dependent and provided by asm/perf_regs.h

Registers are laid out as u64 in the order of the bit order of sample_intr_regs.

This patch also adds a new ABI version PERF_ATTR_SIZE_VER4 because we extend
the perf_event_attr struct with a new u64 field.

Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: cebbert.lkml@gmail.com
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-api@vger.kernel.org
Link: http://lkml.kernel.org/r/1411559322-16548-2-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 893a0d07986f..68d46d536e24 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -79,7 +79,7 @@ struct perf_branch_stack {
         struct perf_branch_entry        entries[0];
 };
 
-struct perf_regs_user {
+struct perf_regs {
         __u64           abi;
         struct pt_regs  *regs;
 };
@@ -600,7 +600,8 @@ struct perf_sample_data {
         struct perf_callchain_entry     *callchain;
         struct perf_raw_record          *raw;
         struct perf_branch_stack        *br_stack;
-        struct perf_regs_user           regs_user;
+        struct perf_regs                regs_user;
+        struct perf_regs                regs_intr;
         u64                             stack_user_size;
         u64                             weight;
         /*
@@ -630,6 +631,8 @@ static inline void perf_sample_data_init(struct perf_sample_data *data,
         data->weight = 0;
         data->data_src.val = PERF_MEM_NA;
         data->txn = 0;
+        data->regs_intr.abi = PERF_SAMPLE_REGS_ABI_NONE;
+        data->regs_intr.regs = NULL;
 }
 
 extern void perf_output_sample(struct perf_output_handle *handle,