[PATCH v3 8/8] perf syscalltbl: Mask off ABI type for MIPS system calls

From: Ian Rogers <irogers@google.com>
To: "Ian Rogers" <irogers@google.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Arnaldo Carvalho de Melo" <acme@kernel.org>,
	"Namhyung Kim" <namhyung@kernel.org>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"Alexander Shishkin" <alexander.shishkin@linux.intel.com>,
	"Jiri Olsa" <jolsa@kernel.org>,
	"Adrian Hunter" <adrian.hunter@intel.com>,
	"Kan Liang" <kan.liang@linux.intel.com>,
	"John Garry" <john.g.garry@oracle.com>,
	"Will Deacon" <will@kernel.org>,
	"James Clark" <james.clark@linaro.org>,
	"Mike Leach" <mike.leach@linaro.org>,
	"Leo Yan" <leo.yan@linux.dev>, guoren <guoren@kernel.org>,
	"Paul Walmsley" <paul.walmsley@sifive.com>,
	"Palmer Dabbelt" <palmer@dabbelt.com>,
	"Albert Ou" <aou@eecs.berkeley.edu>,
	"Charlie Jenkins" <charlie@rivosinc.com>,
	"Bibo Mao" <maobibo@loongson.cn>,
	"Huacai Chen" <chenhuacai@kernel.org>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	"Jiri Slaby" <jirislaby@kernel.org>,
	"Björn Töpel" <bjorn@rivosinc.com>,
	"Howard Chu" <howardchu95@gmail.com>,
	linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	"linux-csky@vger.kernel.org" <linux-csky@vger.kernel.org>,
	linux-riscv@lists.infradead.org, linux-mips@vger.kernel.org,
	"Arnd Bergmann" <arnd@arndb.de>
Subject: [PATCH v3 8/8] perf syscalltbl: Mask off ABI type for MIPS system calls
Date: Wed, 19 Feb 2025 10:56:57 -0800	[thread overview]
Message-ID: <20250219185657.280286-9-irogers@google.com> (raw)
In-Reply-To: <20250219185657.280286-1-irogers@google.com>

Arnd Bergmann described that MIPS system calls don't necessarily start
from 0 as an ABI prefix is applied:
https://lore.kernel.org/lkml/8ed7dfb2-1e4d-4aa4-a04b-0397a89365d1@app.fastmail.com/
When decoding the "id" (aka system call number) for MIPS ignore values
greater-than 1000.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/syscalltbl.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tools/perf/util/syscalltbl.c b/tools/perf/util/syscalltbl.c
index db0d2b81aed1..ace66e69c1bc 100644
--- a/tools/perf/util/syscalltbl.c
+++ b/tools/perf/util/syscalltbl.c
@@ -46,6 +46,14 @@ const char *syscalltbl__name(int e_machine, int id)
 {
 	const struct syscalltbl *table = find_table(e_machine);
 
+	if (e_machine == EM_MIPS && id > 1000) {
+		/*
+		 * MIPS may encode the N32/64/O32 type in the high part of
+		 * syscall number. Mask this off if present. See the values of
+		 * __NR_N32_Linux, __NR_64_Linux, __NR_O32_Linux and __NR_Linux.
+		 */
+		id = id % 1000;
+	}
 	if (table && id >= 0 && id < table->num_to_name_len)
 		return table->num_to_name[id];
 	return NULL;
-- 
2.48.1.601.g30ceb7b040-goog


