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From: Leo Yan <leo.yan@arm.com>
To: Arnaldo Carvalho de Melo <acme@kernel.org>,
	 John Garry <john.g.garry@oracle.com>,
	Will Deacon <will@kernel.org>,
	 James Clark <james.clark@linaro.org>,
	Mike Leach <mike.leach@arm.com>,
	 Suzuki K Poulose <suzuki.poulose@arm.com>,
	 Namhyung Kim <namhyung@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	 Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	 Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
	 Adrian Hunter <adrian.hunter@intel.com>,
	Al Grant <al.grant@arm.com>,
	 Paschalis Mpeis <paschalis.mpeis@arm.com>,
	Amir Ayupov <aaupov@fb.com>
Cc: linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org,
	 linux-perf-users@vger.kernel.org, Leo Yan <leo.yan@arm.com>,
	 Leo Yan <leo.yan@linux.dev>
Subject: [PATCH v11 4/9] perf cs-etm: Refactor instruction size handling
Date: Thu, 02 Jul 2026 20:51:39 +0100	[thread overview]
Message-ID: <20260702-b4-arm_cs_callchain_support_v1-v11-4-846abbf600d7@arm.com> (raw)
In-Reply-To: <20260702-b4-arm_cs_callchain_support_v1-v11-0-846abbf600d7@arm.com>

From: Leo Yan <leo.yan@linaro.org>

This patch introduces a new function cs_etm__instr_size() to calculate
the instruction size based on ISA type and instruction address.

Given the trace data can be MB and most likely that will be A64/A32 on
a lot of platforms, cs_etm__instr_addr() keeps a single ISA type check
for A64/A32 and executes an optimized calculation (addr + offset * 4).

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
 tools/perf/util/cs-etm.c | 43 ++++++++++++++++++++++---------------------
 1 file changed, 22 insertions(+), 21 deletions(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 0ad6cccc292d6bec1596d4826390762a83c04931..838c2d00471333b86d33aa86972a3e852ba6502e 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -1389,6 +1389,18 @@ static inline int cs_etm__t32_instr_size(struct cs_etm_queue *etmq,
 	return ((instrBytes[1] & 0xF8) >= 0xE8) ? 4 : 2;
 }
 
+static inline int cs_etm__instr_size(struct cs_etm_queue *etmq,
+				     struct cs_etm_traceid_queue *tidq,
+				     struct cs_etm_packet *packet,
+				     u64 addr)
+{
+	if (packet->isa == CS_ETM_ISA_T32)
+		return cs_etm__t32_instr_size(etmq, tidq, packet, addr);
+
+	/* Otherwise, 4-byte instruction size for A32/A64 */
+	return 4;
+}
+
 static inline u64 cs_etm__first_executed_instr(struct cs_etm_packet *packet)
 {
 	/*
@@ -1417,19 +1429,17 @@ static inline u64 cs_etm__instr_addr(struct cs_etm_queue *etmq,
 				     struct cs_etm_packet *packet,
 				     u64 offset)
 {
-	if (packet->isa == CS_ETM_ISA_T32) {
-		u64 addr = packet->start_addr;
+	u64 addr = packet->start_addr;
 
-		while (offset) {
-			addr += cs_etm__t32_instr_size(etmq, tidq, packet,
-						       addr);
-			offset--;
-		}
-		return addr;
-	}
+	/* 4-byte instruction size for A32/A64 */
+	if (packet->isa == CS_ETM_ISA_A64 || packet->isa == CS_ETM_ISA_A32)
+		return addr + offset * 4;
 
-	/* Assume a 4 byte instruction size (A32/A64) */
-	return packet->start_addr + offset * 4;
+	while (offset) {
+		addr += cs_etm__instr_size(etmq, tidq, packet, addr);
+		offset--;
+	}
+	return addr;
 }
 
 static void cs_etm__update_last_branch_rb(struct cs_etm_queue *etmq,
@@ -1599,16 +1609,7 @@ static void cs_etm__copy_insn(struct cs_etm_queue *etmq,
 		return;
 	}
 
-	/*
-	 * T32 instruction size might be 32-bit or 16-bit, decide by calling
-	 * cs_etm__t32_instr_size().
-	 */
-	if (packet->isa == CS_ETM_ISA_T32)
-		sample->insn_len = cs_etm__t32_instr_size(etmq, tidq, packet,
-							  sample->ip);
-	/* Otherwise, A64 and A32 instruction size are always 32-bit. */
-	else
-		sample->insn_len = 4;
+	sample->insn_len = cs_etm__instr_size(etmq, tidq, packet, sample->ip);
 
 	cs_etm__frontend_mem_access(etmq, tidq, packet, sample->ip,
 				    sample->insn_len, (void *)sample->insn);

-- 
2.34.1



  parent reply	other threads:[~2026-07-02 19:52 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-02 19:51 [PATCH v11 0/9] perf cs-etm: Support thread stack and callchain Leo Yan
2026-07-02 19:51 ` [PATCH v11 1/9] perf cs-etm: Fix thread leaks on trace queue init failure Leo Yan
2026-07-02 19:51 ` [PATCH v11 2/9] perf cs-etm: Filter synthesized branch samples Leo Yan
2026-07-02 19:51 ` [PATCH v11 3/9] perf cs-etm: Decode ETE exception packets Leo Yan
2026-07-02 19:51 ` Leo Yan [this message]
2026-07-02 19:51 ` [PATCH v11 5/9] perf cs-etm: Use thread-stack for last branch entries Leo Yan
2026-07-02 19:51 ` [PATCH v11 6/9] perf cs-etm: Flush thread stacks after decoder reset Leo Yan
2026-07-02 19:51 ` [PATCH v11 7/9] perf cs-etm: Support call indentation Leo Yan
2026-07-02 19:51 ` [PATCH v11 8/9] perf cs-etm: Synthesize callchains for instruction samples Leo Yan
2026-07-02 19:51 ` [PATCH v11 9/9] perf test: Add Arm CoreSight callchain test Leo Yan
2026-07-04 16:11 ` [PATCH v11 0/9] perf cs-etm: Support thread stack and callchain Namhyung Kim

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