[PATCH v7 1/6] perf: add ability to sample machine state on interrupt
From: Stephane Eranian
Date: Wed Sep 24 2014 - 07:49:18 EST
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@xxxxxxxxxx>
Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
---
include/linux/perf_event.h | 7 ++++--
include/uapi/linux/perf_event.h | 15 ++++++++++++-
kernel/events/core.c | 46 +++++++++++++++++++++++++++++++++++++--
3 files changed, 63 insertions(+), 5 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 893a0d0..68d46d5 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,
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 9269de2..48d4a01 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -137,8 +137,9 @@ enum perf_event_sample_format {
PERF_SAMPLE_DATA_SRC = 1U << 15,
PERF_SAMPLE_IDENTIFIER = 1U << 16,
PERF_SAMPLE_TRANSACTION = 1U << 17,
+ PERF_SAMPLE_REGS_INTR = 1U << 18,
- PERF_SAMPLE_MAX = 1U << 18, /* non-ABI */
+ PERF_SAMPLE_MAX = 1U << 19, /* non-ABI */
};
/*
@@ -238,6 +239,7 @@ enum perf_event_read_format {
#define PERF_ATTR_SIZE_VER2 80 /* add: branch_sample_type */
#define PERF_ATTR_SIZE_VER3 96 /* add: sample_regs_user */
/* add: sample_stack_user */
+#define PERF_ATTR_SIZE_VER4 104 /* add: sample_regs_intr */
/*
* Hardware event_id to monitor via a performance monitoring event:
@@ -334,6 +336,15 @@ struct perf_event_attr {
/* Align to u64. */
__u32 __reserved_2;
+ /*
+ * Defines set of regs to dump for each sample
+ * state captured on:
+ * - precise = 0: PMU interrupt
+ * - precise > 0: sampled instruction
+ *
+ * See asm/perf_regs.h for details.
+ */
+ __u64 sample_regs_intr;
};
#define perf_flags(attr) (*(&(attr)->read_format + 1))
@@ -686,6 +697,8 @@ enum perf_event_type {
* { u64 weight; } && PERF_SAMPLE_WEIGHT
* { u64 data_src; } && PERF_SAMPLE_DATA_SRC
* { u64 transaction; } && PERF_SAMPLE_TRANSACTION
+ * { u64 abi; # enum perf_sample_regs_abi
+ * u64 regs[weight(mask)]; } && PERF_SAMPLE_REGS_INTR
* };
*/
PERF_RECORD_SAMPLE = 9,
diff --git a/kernel/events/core.c b/kernel/events/core.c
index eaa636e..7941343 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -4430,7 +4430,7 @@ perf_output_sample_regs(struct perf_output_handle *handle,
}
}
-static void perf_sample_regs_user(struct perf_regs_user *regs_user,
+static void perf_sample_regs_user(struct perf_regs *regs_user,
struct pt_regs *regs)
{
if (!user_mode(regs)) {
@@ -4446,6 +4446,14 @@ static void perf_sample_regs_user(struct perf_regs_user *regs_user,
}
}
+static void perf_sample_regs_intr(struct perf_regs *regs_intr,
+ struct pt_regs *regs)
+{
+ regs_intr->regs = regs;
+ regs_intr->abi = perf_reg_abi(current);
+}
+
+
/*
* Get remaining task size from user stack pointer.
*
@@ -4827,6 +4835,23 @@ void perf_output_sample(struct perf_output_handle *handle,
if (sample_type & PERF_SAMPLE_TRANSACTION)
perf_output_put(handle, data->txn);
+ if (sample_type & PERF_SAMPLE_REGS_INTR) {
+ u64 abi = data->regs_intr.abi;
+ /*
+ * If there are no regs to dump, notice it through
+ * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
+ */
+ perf_output_put(handle, abi);
+
+ if (abi) {
+ u64 mask = event->attr.sample_regs_intr;
+
+ perf_output_sample_regs(handle,
+ data->regs_intr.regs,
+ mask);
+ }
+ }
+
if (!event->attr.watermark) {
int wakeup_events = event->attr.wakeup_events;
@@ -4913,7 +4938,7 @@ void perf_prepare_sample(struct perf_event_header *header,
* in case new sample type is added, because we could eat
* up the rest of the sample size.
*/
- struct perf_regs_user *uregs = &data->regs_user;
+ struct perf_regs *uregs = &data->regs_user;
u16 stack_size = event->attr.sample_stack_user;
u16 size = sizeof(u64);
@@ -4934,6 +4959,21 @@ void perf_prepare_sample(struct perf_event_header *header,
data->stack_user_size = stack_size;
header->size += size;
}
+
+ if (sample_type & PERF_SAMPLE_REGS_INTR) {
+ /* regs dump ABI info */
+ int size = sizeof(u64);
+
+ perf_sample_regs_intr(&data->regs_intr, regs);
+
+ if (data->regs_intr.regs) {
+ u64 mask = event->attr.sample_regs_intr;
+
+ size += hweight64(mask) * sizeof(u64);
+ }
+
+ header->size += size;
+ }
}
static void perf_event_output(struct perf_event *event,
@@ -7134,6 +7174,8 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr,
ret = -EINVAL;
}
+ if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
+ ret = perf_reg_validate(attr->sample_regs_intr);
out:
return ret;
--
1.7.9.5
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