* [PATCH v1] perf record: Refactor ARM64 leaf caller setup out of arch
@ 2026-05-07 17:06 Ian Rogers
2026-05-08 10:35 ` James Clark
0 siblings, 1 reply; 2+ messages in thread
From: Ian Rogers @ 2026-05-07 17:06 UTC (permalink / raw)
To: John Garry, Will Deacon, James Clark, Mike Leach, Leo Yan,
Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Namhyung Kim, Mark Rutland, Alexander Shishkin, Jiri Olsa,
Ian Rogers, Adrian Hunter, Dapeng Mi, Shimin Guo, linux-kernel,
linux-arm-kernel, linux-perf-users
Code in tools/perf/arch causes portability issues/opaqueness and LTO
issues due to the use of weak symbols. Move the adding of LR to the
sample_user_regs into arm64-frame-pointer-unwind-support.c conditional
on EM_HOST == EM_AARCH64 (false on all non-ARM64 builds). This also
better encapsulates the use of the sampled registers by
get_leaf_frame_caller_aarch64 and the set up by the new
add_leaf_frame_caller_opts_aarch64, exposing opportunities for
possibly sampling PC and SP to help the unwinder.
Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/arch/arm64/util/Build | 1 -
tools/perf/arch/arm64/util/machine.c | 12 ------------
tools/perf/builtin-record.c | 11 +++++------
tools/perf/util/arm64-frame-pointer-unwind-support.c | 6 ++++++
tools/perf/util/arm64-frame-pointer-unwind-support.h | 2 ++
5 files changed, 13 insertions(+), 19 deletions(-)
delete mode 100644 tools/perf/arch/arm64/util/machine.c
diff --git a/tools/perf/arch/arm64/util/Build b/tools/perf/arch/arm64/util/Build
index 4e06a08d281a..638aa6948ab5 100644
--- a/tools/perf/arch/arm64/util/Build
+++ b/tools/perf/arch/arm64/util/Build
@@ -5,7 +5,6 @@ perf-util-y += ../../arm/util/pmu.o
perf-util-y += arm-spe.o
perf-util-y += header.o
perf-util-y += hisi-ptt.o
-perf-util-y += machine.o
perf-util-y += mem-events.o
perf-util-y += pmu.o
perf-util-y += tsc.o
diff --git a/tools/perf/arch/arm64/util/machine.c b/tools/perf/arch/arm64/util/machine.c
deleted file mode 100644
index 80fb13c958d9..000000000000
--- a/tools/perf/arch/arm64/util/machine.c
+++ /dev/null
@@ -1,12 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-#include "callchain.h" // prototype of arch__add_leaf_frame_record_opts
-#include "perf_regs.h"
-#include "record.h"
-
-#define SMPL_REG_MASK(b) (1ULL << (b))
-
-void arch__add_leaf_frame_record_opts(struct record_opts *opts)
-{
- opts->sample_user_regs |= SMPL_REG_MASK(PERF_REG_ARM64_LR);
-}
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 4a5eba498c02..272bba7f4b9e 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -14,6 +14,7 @@
#include "util/parse-events.h"
#include "util/config.h"
+#include "util/arm64-frame-pointer-unwind-support.h"
#include "util/callchain.h"
#include "util/cgroup.h"
#include "util/header.h"
@@ -3230,10 +3231,6 @@ static int record__parse_off_cpu_thresh(const struct option *opt,
return 0;
}
-void __weak arch__add_leaf_frame_record_opts(struct record_opts *opts __maybe_unused)
-{
-}
-
static int parse_control_option(const struct option *opt,
const char *str,
int unset __maybe_unused)
@@ -4319,8 +4316,10 @@ int cmd_record(int argc, const char **argv)
evlist__warn_user_requested_cpus(rec->evlist, rec->opts.target.cpu_list);
- if (callchain_param.enabled && callchain_param.record_mode == CALLCHAIN_FP)
- arch__add_leaf_frame_record_opts(&rec->opts);
+ if (callchain_param.enabled && callchain_param.record_mode == CALLCHAIN_FP) {
+ if (EM_HOST == EM_AARCH64)
+ add_leaf_frame_caller_opts_aarch64(&rec->opts);
+ }
err = -ENOMEM;
if (evlist__create_maps(rec->evlist, &rec->opts.target) < 0) {
diff --git a/tools/perf/util/arm64-frame-pointer-unwind-support.c b/tools/perf/util/arm64-frame-pointer-unwind-support.c
index 858ce2b01812..3af8c7a466e0 100644
--- a/tools/perf/util/arm64-frame-pointer-unwind-support.c
+++ b/tools/perf/util/arm64-frame-pointer-unwind-support.c
@@ -2,6 +2,7 @@
#include "arm64-frame-pointer-unwind-support.h"
#include "callchain.h"
#include "event.h"
+#include "record.h"
#include "unwind.h"
#include <string.h>
@@ -16,6 +17,11 @@ struct entries {
#define SMPL_REG_MASK(b) (1ULL << (b))
+void add_leaf_frame_caller_opts_aarch64(struct record_opts *opts)
+{
+ opts->sample_user_regs |= SMPL_REG_MASK(PERF_REG_ARM64_LR);
+}
+
static bool get_leaf_frame_caller_enabled(struct perf_sample *sample)
{
struct regs_dump *regs;
diff --git a/tools/perf/util/arm64-frame-pointer-unwind-support.h b/tools/perf/util/arm64-frame-pointer-unwind-support.h
index 42d3a45490f5..ba35b295bfcd 100644
--- a/tools/perf/util/arm64-frame-pointer-unwind-support.h
+++ b/tools/perf/util/arm64-frame-pointer-unwind-support.h
@@ -5,8 +5,10 @@
#include <linux/types.h>
struct perf_sample;
+struct record_opts;
struct thread;
+void add_leaf_frame_caller_opts_aarch64(struct record_opts *opts);
u64 get_leaf_frame_caller_aarch64(struct perf_sample *sample, struct thread *thread, int user_idx);
#endif /* __PERF_ARM_FRAME_POINTER_UNWIND_SUPPORT_H */
--
2.54.0.545.g6539524ca2-goog
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v1] perf record: Refactor ARM64 leaf caller setup out of arch
2026-05-07 17:06 [PATCH v1] perf record: Refactor ARM64 leaf caller setup out of arch Ian Rogers
@ 2026-05-08 10:35 ` James Clark
0 siblings, 0 replies; 2+ messages in thread
From: James Clark @ 2026-05-08 10:35 UTC (permalink / raw)
To: Ian Rogers
Cc: John Garry, Will Deacon, Mike Leach, Leo Yan, Peter Zijlstra,
Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Mark Rutland,
Alexander Shishkin, Jiri Olsa, Adrian Hunter, Dapeng Mi,
Shimin Guo, linux-kernel, linux-arm-kernel, linux-perf-users
On 07/05/2026 6:06 pm, Ian Rogers wrote:
> Code in tools/perf/arch causes portability issues/opaqueness and LTO
> issues due to the use of weak symbols. Move the adding of LR to the
> sample_user_regs into arm64-frame-pointer-unwind-support.c conditional
> on EM_HOST == EM_AARCH64 (false on all non-ARM64 builds). This also
> better encapsulates the use of the sampled registers by
> get_leaf_frame_caller_aarch64 and the set up by the new
> add_leaf_frame_caller_opts_aarch64, exposing opportunities for
> possibly sampling PC and SP to help the unwinder.
>
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
> tools/perf/arch/arm64/util/Build | 1 -
> tools/perf/arch/arm64/util/machine.c | 12 ------------
> tools/perf/builtin-record.c | 11 +++++------
> tools/perf/util/arm64-frame-pointer-unwind-support.c | 6 ++++++
> tools/perf/util/arm64-frame-pointer-unwind-support.h | 2 ++
> 5 files changed, 13 insertions(+), 19 deletions(-)
> delete mode 100644 tools/perf/arch/arm64/util/machine.c
>
> diff --git a/tools/perf/arch/arm64/util/Build b/tools/perf/arch/arm64/util/Build
> index 4e06a08d281a..638aa6948ab5 100644
> --- a/tools/perf/arch/arm64/util/Build
> +++ b/tools/perf/arch/arm64/util/Build
> @@ -5,7 +5,6 @@ perf-util-y += ../../arm/util/pmu.o
> perf-util-y += arm-spe.o
> perf-util-y += header.o
> perf-util-y += hisi-ptt.o
> -perf-util-y += machine.o
> perf-util-y += mem-events.o
> perf-util-y += pmu.o
> perf-util-y += tsc.o
> diff --git a/tools/perf/arch/arm64/util/machine.c b/tools/perf/arch/arm64/util/machine.c
> deleted file mode 100644
> index 80fb13c958d9..000000000000
> --- a/tools/perf/arch/arm64/util/machine.c
> +++ /dev/null
> @@ -1,12 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -
> -#include "callchain.h" // prototype of arch__add_leaf_frame_record_opts
> -#include "perf_regs.h"
> -#include "record.h"
> -
> -#define SMPL_REG_MASK(b) (1ULL << (b))
> -
> -void arch__add_leaf_frame_record_opts(struct record_opts *opts)
> -{
> - opts->sample_user_regs |= SMPL_REG_MASK(PERF_REG_ARM64_LR);
> -}
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 4a5eba498c02..272bba7f4b9e 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -14,6 +14,7 @@
> #include "util/parse-events.h"
> #include "util/config.h"
>
> +#include "util/arm64-frame-pointer-unwind-support.h"
> #include "util/callchain.h"
> #include "util/cgroup.h"
> #include "util/header.h"
> @@ -3230,10 +3231,6 @@ static int record__parse_off_cpu_thresh(const struct option *opt,
> return 0;
> }
>
> -void __weak arch__add_leaf_frame_record_opts(struct record_opts *opts __maybe_unused)
> -{
> -}
> -
> static int parse_control_option(const struct option *opt,
> const char *str,
> int unset __maybe_unused)
> @@ -4319,8 +4316,10 @@ int cmd_record(int argc, const char **argv)
>
> evlist__warn_user_requested_cpus(rec->evlist, rec->opts.target.cpu_list);
>
> - if (callchain_param.enabled && callchain_param.record_mode == CALLCHAIN_FP)
> - arch__add_leaf_frame_record_opts(&rec->opts);
> + if (callchain_param.enabled && callchain_param.record_mode == CALLCHAIN_FP) {
> + if (EM_HOST == EM_AARCH64)
> + add_leaf_frame_caller_opts_aarch64(&rec->opts);
> + }
>
> err = -ENOMEM;
> if (evlist__create_maps(rec->evlist, &rec->opts.target) < 0) {
> diff --git a/tools/perf/util/arm64-frame-pointer-unwind-support.c b/tools/perf/util/arm64-frame-pointer-unwind-support.c
> index 858ce2b01812..3af8c7a466e0 100644
> --- a/tools/perf/util/arm64-frame-pointer-unwind-support.c
> +++ b/tools/perf/util/arm64-frame-pointer-unwind-support.c
> @@ -2,6 +2,7 @@
> #include "arm64-frame-pointer-unwind-support.h"
> #include "callchain.h"
> #include "event.h"
> +#include "record.h"
> #include "unwind.h"
> #include <string.h>
>
> @@ -16,6 +17,11 @@ struct entries {
>
> #define SMPL_REG_MASK(b) (1ULL << (b))
>
> +void add_leaf_frame_caller_opts_aarch64(struct record_opts *opts)
> +{
> + opts->sample_user_regs |= SMPL_REG_MASK(PERF_REG_ARM64_LR);
> +}
> +
> static bool get_leaf_frame_caller_enabled(struct perf_sample *sample)
> {
> struct regs_dump *regs;
> diff --git a/tools/perf/util/arm64-frame-pointer-unwind-support.h b/tools/perf/util/arm64-frame-pointer-unwind-support.h
> index 42d3a45490f5..ba35b295bfcd 100644
> --- a/tools/perf/util/arm64-frame-pointer-unwind-support.h
> +++ b/tools/perf/util/arm64-frame-pointer-unwind-support.h
> @@ -5,8 +5,10 @@
> #include <linux/types.h>
>
> struct perf_sample;
> +struct record_opts;
> struct thread;
>
> +void add_leaf_frame_caller_opts_aarch64(struct record_opts *opts);
> u64 get_leaf_frame_caller_aarch64(struct perf_sample *sample, struct thread *thread, int user_idx);
>
> #endif /* __PERF_ARM_FRAME_POINTER_UNWIND_SUPPORT_H */
Reviewed-by: James Clark <james.clark@linaro.org>
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