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* [PATCH 1/3] perf: Use sample_flags for callchain
@ 2022-09-08 21:41 Namhyung Kim
  2022-09-08 21:41 ` [PATCH 2/3] perf/bpf: Always use perf callchains if exist Namhyung Kim
                   ` (3 more replies)
  0 siblings, 4 replies; 8+ messages in thread
From: Namhyung Kim @ 2022-09-08 21:41 UTC (permalink / raw)
  To: Peter Zijlstra, Alexei Starovoitov, Daniel Borkmann,
	Andrii Nakryiko, Song Liu
  Cc: Ingo Molnar, Mark Rutland, Alexander Shishkin,
	Arnaldo Carvalho de Melo, Jiri Olsa, LKML, Martin KaFai Lau,
	Yonghong Song, John Fastabend, KP Singh, Hao Luo,
	Stanislav Fomichev, bpf, Kan Liang, Ravi Bangoria

So that it can call perf_callchain() only if needed.  Historically it used
__PERF_SAMPLE_CALLCHAIN_EARLY but we can do that with sample_flags in the
struct perf_sample_data.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 arch/x86/events/amd/ibs.c  | 4 +++-
 arch/x86/events/intel/ds.c | 8 ++++++--
 kernel/events/core.c       | 2 +-
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index c251bc44c088..dab094166693 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -798,8 +798,10 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs)
 	 * recorded as part of interrupt regs. Thus we need to use rip from
 	 * interrupt regs while unwinding call stack.
 	 */
-	if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
+	if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
 		data.callchain = perf_callchain(event, iregs);
+		data.sample_flags |= PERF_SAMPLE_CALLCHAIN;
+	}
 
 	throttle = perf_event_overflow(event, &data, &regs);
 out:
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index a5275c235c2a..4ba6ab6d0d92 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -1546,8 +1546,10 @@ static void setup_pebs_fixed_sample_data(struct perf_event *event,
 	 * previous PMI context or an (I)RET happened between the record and
 	 * PMI.
 	 */
-	if (sample_type & PERF_SAMPLE_CALLCHAIN)
+	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
 		data->callchain = perf_callchain(event, iregs);
+		data->sample_flags |= PERF_SAMPLE_CALLCHAIN;
+	}
 
 	/*
 	 * We use the interrupt regs as a base because the PEBS record does not
@@ -1719,8 +1721,10 @@ static void setup_pebs_adaptive_sample_data(struct perf_event *event,
 	 * previous PMI context or an (I)RET happened between the record and
 	 * PMI.
 	 */
-	if (sample_type & PERF_SAMPLE_CALLCHAIN)
+	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
 		data->callchain = perf_callchain(event, iregs);
+		data->sample_flags |= PERF_SAMPLE_CALLCHAIN;
+	}
 
 	*regs = *iregs;
 	/* The ip in basic is EventingIP */
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 15d27b14c827..b8af9fdbf26f 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7323,7 +7323,7 @@ void perf_prepare_sample(struct perf_event_header *header,
 	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
 		int size = 1;
 
-		if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
+		if (filtered_sample_type & PERF_SAMPLE_CALLCHAIN)
 			data->callchain = perf_callchain(event, regs);
 
 		size += data->callchain->nr;
-- 
2.37.2.789.g6183377224-goog


^ permalink raw reply related	[flat|nested] 8+ messages in thread
* [PATCH 2/3] perf/bpf: Always use perf callchains if exist
  2022-09-08 21:41 [PATCH 1/3] perf: Use sample_flags for callchain Namhyung Kim
@ 2022-09-08 21:41 ` Namhyung Kim
  2022-09-09 21:55   ` sdf
  2022-09-15 14:16   ` [tip: perf/core] " tip-bot2 for Namhyung Kim
  2022-09-08 21:41 ` [PATCH 3/3] perf: Kill __PERF_SAMPLE_CALLCHAIN_EARLY Namhyung Kim
                   ` (2 subsequent siblings)
  3 siblings, 2 replies; 8+ messages in thread
From: Namhyung Kim @ 2022-09-08 21:41 UTC (permalink / raw)
  To: Peter Zijlstra, Alexei Starovoitov, Daniel Borkmann,
	Andrii Nakryiko, Song Liu
  Cc: Ingo Molnar, Mark Rutland, Alexander Shishkin,
	Arnaldo Carvalho de Melo, Jiri Olsa, LKML, Martin KaFai Lau,
	Yonghong Song, John Fastabend, KP Singh, Hao Luo,
	Stanislav Fomichev, bpf, Kan Liang, Ravi Bangoria

If the perf_event has PERF_SAMPLE_CALLCHAIN, BPF can use it for stack trace.
The problematic cases like PEBS and IBS already handled in the PMU driver and
they filled the callchain info in the sample data.  For others, we can call
perf_callchain() before the BPF handler.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 kernel/bpf/stackmap.c |  4 ++--
 kernel/events/core.c  | 12 ++++++++++--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index 1adbe67cdb95..aecea7451b61 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -338,7 +338,7 @@ BPF_CALL_3(bpf_get_stackid_pe, struct bpf_perf_event_data_kern *, ctx,
 	int ret;
 
 	/* perf_sample_data doesn't have callchain, use bpf_get_stackid */
-	if (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
+	if (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN))
 		return bpf_get_stackid((unsigned long)(ctx->regs),
 				       (unsigned long) map, flags, 0, 0);
 
@@ -506,7 +506,7 @@ BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx,
 	int err = -EINVAL;
 	__u64 nr_kernel;
 
-	if (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
+	if (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN))
 		return __bpf_get_stack(regs, NULL, NULL, buf, size, flags);
 
 	if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |
diff --git a/kernel/events/core.c b/kernel/events/core.c
index b8af9fdbf26f..2ea93ce75ad4 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10003,8 +10003,16 @@ static void bpf_overflow_handler(struct perf_event *event,
 		goto out;
 	rcu_read_lock();
 	prog = READ_ONCE(event->prog);
-	if (prog)
+	if (prog) {
+		if (prog->call_get_stack &&
+		    (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) &&
+		    !(data->sample_flags & PERF_SAMPLE_CALLCHAIN)) {
+			data->callchain = perf_callchain(event, regs);
+			data->sample_flags |= PERF_SAMPLE_CALLCHAIN;
+		}
+
 		ret = bpf_prog_run(prog, &ctx);
+	}
 	rcu_read_unlock();
 out:
 	__this_cpu_dec(bpf_prog_active);
@@ -10030,7 +10038,7 @@ static int perf_event_set_bpf_handler(struct perf_event *event,
 
 	if (event->attr.precise_ip &&
 	    prog->call_get_stack &&
-	    (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) ||
+	    (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) ||
 	     event->attr.exclude_callchain_kernel ||
 	     event->attr.exclude_callchain_user)) {
 		/*
-- 
2.37.2.789.g6183377224-goog


^ permalink raw reply related	[flat|nested] 8+ messages in thread
* [PATCH 3/3] perf: Kill __PERF_SAMPLE_CALLCHAIN_EARLY
  2022-09-08 21:41 [PATCH 1/3] perf: Use sample_flags for callchain Namhyung Kim
  2022-09-08 21:41 ` [PATCH 2/3] perf/bpf: Always use perf callchains if exist Namhyung Kim
@ 2022-09-08 21:41 ` Namhyung Kim
  2022-09-15 14:16   ` [tip: perf/core] " tip-bot2 for Namhyung Kim
  2022-09-09 12:37 ` [PATCH 1/3] perf: Use sample_flags for callchain Liang, Kan
  2022-09-15 14:16 ` [tip: perf/core] " tip-bot2 for Namhyung Kim
  3 siblings, 1 reply; 8+ messages in thread
From: Namhyung Kim @ 2022-09-08 21:41 UTC (permalink / raw)
  To: Peter Zijlstra, Alexei Starovoitov, Daniel Borkmann,
	Andrii Nakryiko, Song Liu
  Cc: Ingo Molnar, Mark Rutland, Alexander Shishkin,
	Arnaldo Carvalho de Melo, Jiri Olsa, LKML, Martin KaFai Lau,
	Yonghong Song, John Fastabend, KP Singh, Hao Luo,
	Stanislav Fomichev, bpf, Kan Liang, Ravi Bangoria

There's no in-tree user anymore.  Let's get rid of it.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 arch/x86/events/amd/ibs.c       | 10 ----------
 arch/x86/events/intel/core.c    |  3 ---
 include/uapi/linux/perf_event.h |  2 --
 3 files changed, 15 deletions(-)

diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index dab094166693..ce5720bfb350 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -300,16 +300,6 @@ static int perf_ibs_init(struct perf_event *event)
 	hwc->config_base = perf_ibs->msr;
 	hwc->config = config;
 
-	/*
-	 * rip recorded by IbsOpRip will not be consistent with rsp and rbp
-	 * recorded as part of interrupt regs. Thus we need to use rip from
-	 * interrupt regs while unwinding call stack. Setting _EARLY flag
-	 * makes sure we unwind call-stack before perf sample rip is set to
-	 * IbsOpRip.
-	 */
-	if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
-		event->attr.sample_type |= __PERF_SAMPLE_CALLCHAIN_EARLY;
-
 	return 0;
 }
 
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index ba101c28dcc9..fcd43878a24d 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3846,9 +3846,6 @@ static int intel_pmu_hw_config(struct perf_event *event)
 		}
 		if (x86_pmu.pebs_aliases)
 			x86_pmu.pebs_aliases(event);
-
-		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
-			event->attr.sample_type |= __PERF_SAMPLE_CALLCHAIN_EARLY;
 	}
 
 	if (needs_branch_stack(event)) {
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index dca16582885f..e639c74cf5fb 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -164,8 +164,6 @@ enum perf_event_sample_format {
 	PERF_SAMPLE_WEIGHT_STRUCT		= 1U << 24,
 
 	PERF_SAMPLE_MAX = 1U << 25,		/* non-ABI */
-
-	__PERF_SAMPLE_CALLCHAIN_EARLY		= 1ULL << 63, /* non-ABI; internal use */
 };
 
 #define PERF_SAMPLE_WEIGHT_TYPE	(PERF_SAMPLE_WEIGHT | PERF_SAMPLE_WEIGHT_STRUCT)
-- 
2.37.2.789.g6183377224-goog


^ permalink raw reply related	[flat|nested] 8+ messages in thread
* Re: [PATCH 1/3] perf: Use sample_flags for callchain
  2022-09-08 21:41 [PATCH 1/3] perf: Use sample_flags for callchain Namhyung Kim
  2022-09-08 21:41 ` [PATCH 2/3] perf/bpf: Always use perf callchains if exist Namhyung Kim
  2022-09-08 21:41 ` [PATCH 3/3] perf: Kill __PERF_SAMPLE_CALLCHAIN_EARLY Namhyung Kim
@ 2022-09-09 12:37 ` Liang, Kan
  2022-09-15 14:16 ` [tip: perf/core] " tip-bot2 for Namhyung Kim
  3 siblings, 0 replies; 8+ messages in thread
From: Liang, Kan @ 2022-09-09 12:37 UTC (permalink / raw)
  To: Namhyung Kim, Peter Zijlstra, Alexei Starovoitov,
	Daniel Borkmann, Andrii Nakryiko, Song Liu
  Cc: Ingo Molnar, Mark Rutland, Alexander Shishkin,
	Arnaldo Carvalho de Melo, Jiri Olsa, LKML, Martin KaFai Lau,
	Yonghong Song, John Fastabend, KP Singh, Hao Luo,
	Stanislav Fomichev, bpf, Ravi Bangoria



On 2022-09-08 5:41 p.m., Namhyung Kim wrote:
> So that it can call perf_callchain() only if needed.  Historically it used
> __PERF_SAMPLE_CALLCHAIN_EARLY but we can do that with sample_flags in the
> struct perf_sample_data.
> 
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>

The series look good to me.

Reviewed-by: Kan Liang <kan.liang@linux.intel.com>

Thanks,
Kan

> ---
>  arch/x86/events/amd/ibs.c  | 4 +++-
>  arch/x86/events/intel/ds.c | 8 ++++++--
>  kernel/events/core.c       | 2 +-
>  3 files changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
> index c251bc44c088..dab094166693 100644
> --- a/arch/x86/events/amd/ibs.c
> +++ b/arch/x86/events/amd/ibs.c
> @@ -798,8 +798,10 @@ static int perf_ibs_handle_irq(struct perf_ibs *perf_ibs, struct pt_regs *iregs)
>  	 * recorded as part of interrupt regs. Thus we need to use rip from
>  	 * interrupt regs while unwinding call stack.
>  	 */
> -	if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
> +	if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
>  		data.callchain = perf_callchain(event, iregs);
> +		data.sample_flags |= PERF_SAMPLE_CALLCHAIN;
> +	}
>  
>  	throttle = perf_event_overflow(event, &data, &regs);
>  out:
> diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
> index a5275c235c2a..4ba6ab6d0d92 100644
> --- a/arch/x86/events/intel/ds.c
> +++ b/arch/x86/events/intel/ds.c
> @@ -1546,8 +1546,10 @@ static void setup_pebs_fixed_sample_data(struct perf_event *event,
>  	 * previous PMI context or an (I)RET happened between the record and
>  	 * PMI.
>  	 */
> -	if (sample_type & PERF_SAMPLE_CALLCHAIN)
> +	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
>  		data->callchain = perf_callchain(event, iregs);
> +		data->sample_flags |= PERF_SAMPLE_CALLCHAIN;
> +	}
>  
>  	/*
>  	 * We use the interrupt regs as a base because the PEBS record does not
> @@ -1719,8 +1721,10 @@ static void setup_pebs_adaptive_sample_data(struct perf_event *event,
>  	 * previous PMI context or an (I)RET happened between the record and
>  	 * PMI.
>  	 */
> -	if (sample_type & PERF_SAMPLE_CALLCHAIN)
> +	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
>  		data->callchain = perf_callchain(event, iregs);
> +		data->sample_flags |= PERF_SAMPLE_CALLCHAIN;
> +	}
>  
>  	*regs = *iregs;
>  	/* The ip in basic is EventingIP */
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 15d27b14c827..b8af9fdbf26f 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -7323,7 +7323,7 @@ void perf_prepare_sample(struct perf_event_header *header,
>  	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
>  		int size = 1;
>  
> -		if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
> +		if (filtered_sample_type & PERF_SAMPLE_CALLCHAIN)
>  			data->callchain = perf_callchain(event, regs);
>  
>  		size += data->callchain->nr;

^ permalink raw reply	[flat|nested] 8+ messages in thread
* Re: [PATCH 2/3] perf/bpf: Always use perf callchains if exist
  2022-09-08 21:41 ` [PATCH 2/3] perf/bpf: Always use perf callchains if exist Namhyung Kim
@ 2022-09-09 21:55   ` sdf
  2022-09-15 14:16   ` [tip: perf/core] " tip-bot2 for Namhyung Kim
  1 sibling, 0 replies; 8+ messages in thread
From: sdf @ 2022-09-09 21:55 UTC (permalink / raw)
  To: Namhyung Kim
  Cc: Peter Zijlstra, Alexei Starovoitov, Daniel Borkmann,
	Andrii Nakryiko, Song Liu, Ingo Molnar, Mark Rutland,
	Alexander Shishkin, Arnaldo Carvalho de Melo, Jiri Olsa, LKML,
	Martin KaFai Lau, Yonghong Song, John Fastabend, KP Singh,
	Hao Luo, bpf, Kan Liang, Ravi Bangoria

On 09/08, Namhyung Kim wrote:
> If the perf_event has PERF_SAMPLE_CALLCHAIN, BPF can use it for stack  
> trace.
> The problematic cases like PEBS and IBS already handled in the PMU driver  
> and
> they filled the callchain info in the sample data.  For others, we can  
> call
> perf_callchain() before the BPF handler.

> Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Reviewed-by: Stanislav Fomichev <sdf@google.com>

At least from the description it make sense. We're filling a callchain
when it's been requested by the event, but it's missing on the
sample data (aka, software fallback?). perf_callchain also seems to
always fallback to &__empty_callchain in case of an error, so seems
safe.

> ---
>   kernel/bpf/stackmap.c |  4 ++--
>   kernel/events/core.c  | 12 ++++++++++--
>   2 files changed, 12 insertions(+), 4 deletions(-)

> diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
> index 1adbe67cdb95..aecea7451b61 100644
> --- a/kernel/bpf/stackmap.c
> +++ b/kernel/bpf/stackmap.c
> @@ -338,7 +338,7 @@ BPF_CALL_3(bpf_get_stackid_pe, struct  
> bpf_perf_event_data_kern *, ctx,
>   	int ret;

>   	/* perf_sample_data doesn't have callchain, use bpf_get_stackid */
> -	if (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
> +	if (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN))
>   		return bpf_get_stackid((unsigned long)(ctx->regs),
>   				       (unsigned long) map, flags, 0, 0);

> @@ -506,7 +506,7 @@ BPF_CALL_4(bpf_get_stack_pe, struct  
> bpf_perf_event_data_kern *, ctx,
>   	int err = -EINVAL;
>   	__u64 nr_kernel;

> -	if (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
> +	if (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN))
>   		return __bpf_get_stack(regs, NULL, NULL, buf, size, flags);

>   	if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index b8af9fdbf26f..2ea93ce75ad4 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -10003,8 +10003,16 @@ static void bpf_overflow_handler(struct  
> perf_event *event,
>   		goto out;
>   	rcu_read_lock();
>   	prog = READ_ONCE(event->prog);
> -	if (prog)
> +	if (prog) {
> +		if (prog->call_get_stack &&
> +		    (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) &&
> +		    !(data->sample_flags & PERF_SAMPLE_CALLCHAIN)) {
> +			data->callchain = perf_callchain(event, regs);
> +			data->sample_flags |= PERF_SAMPLE_CALLCHAIN;
> +		}
> +
>   		ret = bpf_prog_run(prog, &ctx);
> +	}
>   	rcu_read_unlock();
>   out:
>   	__this_cpu_dec(bpf_prog_active);
> @@ -10030,7 +10038,7 @@ static int perf_event_set_bpf_handler(struct  
> perf_event *event,

>   	if (event->attr.precise_ip &&
>   	    prog->call_get_stack &&
> -	    (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) ||
> +	    (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) ||
>   	     event->attr.exclude_callchain_kernel ||
>   	     event->attr.exclude_callchain_user)) {
>   		/*
> --
> 2.37.2.789.g6183377224-goog


^ permalink raw reply	[flat|nested] 8+ messages in thread
* [tip: perf/core] perf: Kill __PERF_SAMPLE_CALLCHAIN_EARLY
  2022-09-08 21:41 ` [PATCH 3/3] perf: Kill __PERF_SAMPLE_CALLCHAIN_EARLY Namhyung Kim
@ 2022-09-15 14:16   ` tip-bot2 for Namhyung Kim
  0 siblings, 0 replies; 8+ messages in thread
From: tip-bot2 for Namhyung Kim @ 2022-09-15 14:16 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: Namhyung Kim, Peter Zijlstra (Intel), x86, linux-kernel

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     b4e12b2d70fd9eccdb3cef8015dc1788ca38e3fd
Gitweb:        https://git.kernel.org/tip/b4e12b2d70fd9eccdb3cef8015dc1788ca38e3fd
Author:        Namhyung Kim <namhyung@kernel.org>
AuthorDate:    Thu, 08 Sep 2022 14:41:04 -07:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Tue, 13 Sep 2022 15:03:23 +02:00

perf: Kill __PERF_SAMPLE_CALLCHAIN_EARLY

There's no in-tree user anymore.  Let's get rid of it.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220908214104.3851807-3-namhyung@kernel.org
---
 arch/x86/events/amd/ibs.c       | 10 ----------
 arch/x86/events/intel/core.c    |  3 ---
 include/uapi/linux/perf_event.h |  2 --
 3 files changed, 15 deletions(-)

diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index dab0941..ce5720b 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -300,16 +300,6 @@ static int perf_ibs_init(struct perf_event *event)
 	hwc->config_base = perf_ibs->msr;
 	hwc->config = config;
 
-	/*
-	 * rip recorded by IbsOpRip will not be consistent with rsp and rbp
-	 * recorded as part of interrupt regs. Thus we need to use rip from
-	 * interrupt regs while unwinding call stack. Setting _EARLY flag
-	 * makes sure we unwind call-stack before perf sample rip is set to
-	 * IbsOpRip.
-	 */
-	if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
-		event->attr.sample_type |= __PERF_SAMPLE_CALLCHAIN_EARLY;
-
 	return 0;
 }
 
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 7f4e7e6..b16c91a 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3868,9 +3868,6 @@ static int intel_pmu_hw_config(struct perf_event *event)
 		}
 		if (x86_pmu.pebs_aliases)
 			x86_pmu.pebs_aliases(event);
-
-		if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
-			event->attr.sample_type |= __PERF_SAMPLE_CALLCHAIN_EARLY;
 	}
 
 	if (needs_branch_stack(event)) {
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index dca1658..e639c74 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -164,8 +164,6 @@ enum perf_event_sample_format {
 	PERF_SAMPLE_WEIGHT_STRUCT		= 1U << 24,
 
 	PERF_SAMPLE_MAX = 1U << 25,		/* non-ABI */
-
-	__PERF_SAMPLE_CALLCHAIN_EARLY		= 1ULL << 63, /* non-ABI; internal use */
 };
 
 #define PERF_SAMPLE_WEIGHT_TYPE	(PERF_SAMPLE_WEIGHT | PERF_SAMPLE_WEIGHT_STRUCT)

^ permalink raw reply related	[flat|nested] 8+ messages in thread
* [tip: perf/core] perf/bpf: Always use perf callchains if exist
  2022-09-08 21:41 ` [PATCH 2/3] perf/bpf: Always use perf callchains if exist Namhyung Kim
  2022-09-09 21:55   ` sdf
@ 2022-09-15 14:16   ` tip-bot2 for Namhyung Kim
  1 sibling, 0 replies; 8+ messages in thread
From: tip-bot2 for Namhyung Kim @ 2022-09-15 14:16 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: Namhyung Kim, Peter Zijlstra (Intel), x86, linux-kernel

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     16817ad7e8b31728b44ff9f17d8d894ed8a450d0
Gitweb:        https://git.kernel.org/tip/16817ad7e8b31728b44ff9f17d8d894ed8a450d0
Author:        Namhyung Kim <namhyung@kernel.org>
AuthorDate:    Thu, 08 Sep 2022 14:41:03 -07:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Tue, 13 Sep 2022 15:03:22 +02:00

perf/bpf: Always use perf callchains if exist

If the perf_event has PERF_SAMPLE_CALLCHAIN, BPF can use it for stack trace.
The problematic cases like PEBS and IBS already handled in the PMU driver and
they filled the callchain info in the sample data.  For others, we can call
perf_callchain() before the BPF handler.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220908214104.3851807-2-namhyung@kernel.org
---
 kernel/bpf/stackmap.c |  4 ++--
 kernel/events/core.c  | 12 ++++++++++--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index 1adbe67..aecea74 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -338,7 +338,7 @@ BPF_CALL_3(bpf_get_stackid_pe, struct bpf_perf_event_data_kern *, ctx,
 	int ret;
 
 	/* perf_sample_data doesn't have callchain, use bpf_get_stackid */
-	if (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
+	if (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN))
 		return bpf_get_stackid((unsigned long)(ctx->regs),
 				       (unsigned long) map, flags, 0, 0);
 
@@ -506,7 +506,7 @@ BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx,
 	int err = -EINVAL;
 	__u64 nr_kernel;
 
-	if (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
+	if (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN))
 		return __bpf_get_stack(regs, NULL, NULL, buf, size, flags);
 
 	if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |
diff --git a/kernel/events/core.c b/kernel/events/core.c
index c98ecf3..7da5515 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10000,8 +10000,16 @@ static void bpf_overflow_handler(struct perf_event *event,
 		goto out;
 	rcu_read_lock();
 	prog = READ_ONCE(event->prog);
-	if (prog)
+	if (prog) {
+		if (prog->call_get_stack &&
+		    (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) &&
+		    !(data->sample_flags & PERF_SAMPLE_CALLCHAIN)) {
+			data->callchain = perf_callchain(event, regs);
+			data->sample_flags |= PERF_SAMPLE_CALLCHAIN;
+		}
+
 		ret = bpf_prog_run(prog, &ctx);
+	}
 	rcu_read_unlock();
 out:
 	__this_cpu_dec(bpf_prog_active);
@@ -10027,7 +10035,7 @@ static int perf_event_set_bpf_handler(struct perf_event *event,
 
 	if (event->attr.precise_ip &&
 	    prog->call_get_stack &&
-	    (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) ||
+	    (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) ||
 	     event->attr.exclude_callchain_kernel ||
 	     event->attr.exclude_callchain_user)) {
 		/*

^ permalink raw reply related	[flat|nested] 8+ messages in thread
* [tip: perf/core] perf: Use sample_flags for callchain
  2022-09-08 21:41 [PATCH 1/3] perf: Use sample_flags for callchain Namhyung Kim
                   ` (2 preceding siblings ...)
  2022-09-09 12:37 ` [PATCH 1/3] perf: Use sample_flags for callchain Liang, Kan
@ 2022-09-15 14:16 ` tip-bot2 for Namhyung Kim
  3 siblings, 0 replies; 8+ messages in thread
From: tip-bot2 for Namhyung Kim @ 2022-09-15 14:16 UTC (permalink / raw)
  To: linux-tip-commits; +Cc: Namhyung Kim, Peter Zijlstra (Intel), x86, linux-kernel

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     3749d33e510c3dc695b3a5886b706310890d7ebd
Gitweb:        https://git.kernel.org/tip/3749d33e510c3dc695b3a5886b706310890d7ebd
Author:        Namhyung Kim <namhyung@kernel.org>
AuthorDate:    Thu, 08 Sep 2022 14:41:02 -07:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Tue, 13 Sep 2022 15:03:22 +02:00

perf: Use sample_flags for callchain

So that it can call perf_callchain() only if needed.  Historically it used
__PERF_SAMPLE_CALLCHAIN_EARLY but we can do that with sample_flags in the
struct perf_sample_data.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220908214104.3851807-1-namhyung@kernel.org
---
 arch/x86/events/amd/ibs.c  | 4 +++-
 arch/x86/events/intel/ds.c | 8 ++++++--
 kernel/events/core.c       | 2 +-
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index c251bc4..dab0941 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -798,8 +798,10 @@ fail:
 	 * recorded as part of interrupt regs. Thus we need to use rip from
 	 * interrupt regs while unwinding call stack.
 	 */
-	if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
+	if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
 		data.callchain = perf_callchain(event, iregs);
+		data.sample_flags |= PERF_SAMPLE_CALLCHAIN;
+	}
 
 	throttle = perf_event_overflow(event, &data, &regs);
 out:
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index a5275c2..4ba6ab6 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -1546,8 +1546,10 @@ static void setup_pebs_fixed_sample_data(struct perf_event *event,
 	 * previous PMI context or an (I)RET happened between the record and
 	 * PMI.
 	 */
-	if (sample_type & PERF_SAMPLE_CALLCHAIN)
+	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
 		data->callchain = perf_callchain(event, iregs);
+		data->sample_flags |= PERF_SAMPLE_CALLCHAIN;
+	}
 
 	/*
 	 * We use the interrupt regs as a base because the PEBS record does not
@@ -1719,8 +1721,10 @@ static void setup_pebs_adaptive_sample_data(struct perf_event *event,
 	 * previous PMI context or an (I)RET happened between the record and
 	 * PMI.
 	 */
-	if (sample_type & PERF_SAMPLE_CALLCHAIN)
+	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
 		data->callchain = perf_callchain(event, iregs);
+		data->sample_flags |= PERF_SAMPLE_CALLCHAIN;
+	}
 
 	*regs = *iregs;
 	/* The ip in basic is EventingIP */
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 3e90e45..c98ecf3 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7320,7 +7320,7 @@ void perf_prepare_sample(struct perf_event_header *header,
 	if (sample_type & PERF_SAMPLE_CALLCHAIN) {
 		int size = 1;
 
-		if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
+		if (filtered_sample_type & PERF_SAMPLE_CALLCHAIN)
 			data->callchain = perf_callchain(event, regs);
 
 		size += data->callchain->nr;

^ permalink raw reply related	[flat|nested] 8+ messages in thread
end of thread, other threads:[~2022-09-15 14:16 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-09-08 21:41 [PATCH 1/3] perf: Use sample_flags for callchain Namhyung Kim
2022-09-08 21:41 ` [PATCH 2/3] perf/bpf: Always use perf callchains if exist Namhyung Kim
2022-09-09 21:55   ` sdf
2022-09-15 14:16   ` [tip: perf/core] " tip-bot2 for Namhyung Kim
2022-09-08 21:41 ` [PATCH 3/3] perf: Kill __PERF_SAMPLE_CALLCHAIN_EARLY Namhyung Kim
2022-09-15 14:16   ` [tip: perf/core] " tip-bot2 for Namhyung Kim
2022-09-09 12:37 ` [PATCH 1/3] perf: Use sample_flags for callchain Liang, Kan
2022-09-15 14:16 ` [tip: perf/core] " tip-bot2 for Namhyung Kim

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