linux-kernel - [PATCH v2 5/6] perf parse-events: Vary default_breakpoint

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Message-Id: <20240904050606.752788-6-irogers@google.com>
Date: Tue,  3 Sep 2024 22:06:05 -0700
From: Ian Rogers <irogers@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>, 
	Kan Liang <kan.liang@...ux.intel.com>, Athira Rajeev <atrajeev@...ux.vnet.ibm.com>, 
	Dominique Martinet <asmadeus@...ewreck.org>, Yang Jihong <yangjihong@...edance.com>, 
	Colin Ian King <colin.i.king@...il.com>, Chaitanya S Prakash <chaitanyas.prakash@....com>, 
	"Masami Hiramatsu (Google)" <mhiramat@...nel.org>, James Clark <james.clark@...aro.org>, 
	John Garry <john.g.garry@...cle.com>, Junhao He <hejunhao3@...wei.com>, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 5/6] perf parse-events: Vary default_breakpoint_len on i386
 and arm64

On arm64 the breakpoint length should be 4-bytes but 8-bytes is
tolerated as perf passes that as sizeof(long). Just pass the correct
value.

On i386 the sizeof(long) check in the kernel needs to match the
kernel's long size. Check using an environment (uname checks) whether
4 or 8 bytes needs to be passed. Cache the value in a static.

Signed-off-by: Ian Rogers <irogers@...gle.com>
---
 tools/perf/util/parse-events.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 792e5ed94870..fa71f7f1d8d3 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -8,6 +8,7 @@
 #include <sys/ioctl.h>
 #include <sys/param.h>
 #include "term.h"
+#include "env.h"
 #include "evlist.h"
 #include "evsel.h"
 #include <subcmd/parse-options.h>
@@ -672,7 +673,22 @@ static int add_tracepoint_multi_sys(struct parse_events_state *parse_state,
 
 size_t default_breakpoint_len(void)
 {
+#if defined(__i386__)
+	static int len;
+
+	if (len == 0) {
+		struct perf_env env = {};
+
+		perf_env__init(&env);
+		len = perf_env__kernel_is_64_bit(&env) ? sizeof(u64) : sizeof(long);
+		perf_env__exit(&env);
+	}
+	return len;
+#elif defined(__aarch64__)
+	return 4;
+#else
 	return sizeof(long);
+#endif
 }
 
 static int
-- 
2.46.0.469.g59c65b2a67-goog