Commit 34af56af authored Jun 06, 2023 by Leo Yan Committed by Arnaldo Carvalho de Melo Aug 16, 2023

perf parse-regs: Introduce functions perf_arch_reg_{ip|sp}()



The current code uses macros PERF_REG_IP and PERF_REG_SP for parsing
registers and we build perf with these macros statically, which means it
only can correctly analyze CPU registers for the native architecture and
fails to support cross analysis (e.g. we build perf on x86 and cannot
analyze Arm64's registers).

We need to generalize util/perf_regs.c for support multi architectures,
as a first step, this commit introduces new functions perf_arch_reg_ip()
and perf_arch_reg_sp(), these two functions dynamically return IP and SP
register index respectively according to the parameter "arch".

Every architecture has its own functions (like __perf_reg_ip_arm64 and
__perf_reg_sp_arm64), these architecture specific functions are defined
in each arch source file under folder util/perf-regs-arch; at the end
all of them are built into the tool for cross analysis.

Committer notes:

Make DWARF_MINIMAL_REGS() an inline function, so that we can use the
__maybe_unused attribute for the 'arch' parameter, as this will avoid a
build failure when that variable is unused in the callers. That happens
when building on unsupported architectures, the ones without
HAVE_PERF_REGS_SUPPORT defined.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Eric Lin <eric.lin@sifive.com>
Cc: Fangrui Song <maskray@google.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Babrou <ivan@cloudflare.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Ming Wang <wangming01@loongson.cn>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-csky@vger.kernel.org
Cc: linux-riscv@lists.infradead.org
Link: https://lore.kernel.org/r/20230606014559.21783-3-leo.yan@linaro.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent 5000e7f6

tools/perf/util/evsel.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -845,6 +845,7 @@ static void __evsel__config_callchain(struct evsel evsel, struct record_opts o
		{
		bool function = evsel__is_function_event(evsel);
		struct perf_event_attr *attr = &evsel->core.attr;
		const char *arch = perf_env__arch(evsel__env(evsel));

		evsel__set_sample_bit(evsel, CALLCHAIN);

		@@ -877,8 +878,9 @@ static void __evsel__config_callchain(struct evsel evsel, struct record_opts o
		if (!function) {
		evsel__set_sample_bit(evsel, REGS_USER);
		evsel__set_sample_bit(evsel, STACK_USER);
		if (opts->sample_user_regs && DWARF_MINIMAL_REGS != PERF_REGS_MASK) {
		attr->sample_regs_user \|= DWARF_MINIMAL_REGS;
		if (opts->sample_user_regs &&
		DWARF_MINIMAL_REGS(arch) != PERF_REGS_MASK) {
		attr->sample_regs_user \|= DWARF_MINIMAL_REGS(arch);
		pr_warning("WARNING: The use of --call-graph=dwarf may require all the user registers, "
		"specifying a subset with --user-regs may render DWARF unwinding unreliable, "
		"so the minimal registers set (IP, SP) is explicitly forced.\n");

tools/perf/util/perf-regs-arch/perf_regs_aarch64.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -83,4 +83,14 @@ const char *__perf_reg_name_arm64(int id)
		return NULL;
		}

		uint64_t __perf_reg_ip_arm64(void)
		{
		return PERF_REG_ARM64_PC;
		}

		uint64_t __perf_reg_sp_arm64(void)
		{
		return PERF_REG_ARM64_SP;
		}

		#endif

tools/perf/util/perf-regs-arch/perf_regs_arm.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -47,4 +47,14 @@ const char *__perf_reg_name_arm(int id)
		return NULL;
		}

		uint64_t __perf_reg_ip_arm(void)
		{
		return PERF_REG_ARM_PC;
		}

		uint64_t __perf_reg_sp_arm(void)
		{
		return PERF_REG_ARM_SP;
		}

		#endif

tools/perf/util/perf-regs-arch/perf_regs_csky.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -87,4 +87,14 @@ const char *__perf_reg_name_csky(int id)
		return NULL;
		}

		uint64_t __perf_reg_ip_csky(void)
		{
		return PERF_REG_CSKY_PC;
		}

		uint64_t __perf_reg_sp_csky(void)
		{
		return PERF_REG_CSKY_SP;
		}

		#endif

tools/perf/util/perf-regs-arch/perf_regs_loongarch.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -78,4 +78,14 @@ const char *__perf_reg_name_loongarch(int id)
		return NULL;
		}

		uint64_t __perf_reg_ip_loongarch(void)
		{
		return PERF_REG_LOONGARCH_PC;
		}

		uint64_t __perf_reg_sp_loongarch(void)
		{
		return PERF_REG_LOONGARCH_R3;
		}

		#endif