From 60e2364e60e86e81bc6377f49779779e6120977f Mon Sep 17 00:00:00 2001 From: Stephane Eranian Date: Wed, 24 Sep 2014 13:48:37 +0200 Subject: [PATCH] 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 Signed-off-by: Stephane Eranian Signed-off-by: Peter Zijlstra (Intel) Cc: cebbert.lkml@gmail.com Cc: Arnaldo Carvalho de Melo Cc: Linus Torvalds 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 --- 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 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, diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 9d845404d875..9b79abbd1ab8 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 1cd5eef1fcdd..c2be1597ece7 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4460,7 +4460,7 @@ 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)) { @@ -4476,6 +4476,14 @@ 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. * @@ -4857,6 +4865,23 @@ 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; @@ -4943,7 +4968,7 @@ 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); @@ -4964,6 +4989,21 @@ 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, @@ -7151,6 +7191,8 @@ 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; -- 2.20.1