[PATCH v3 03/20] perf arm-spe: Refactor payload size calculation

[Leo Yan]

This patch defines macro to extract "sz" field from header, and renames
the function payloadlen() to arm_spe_payload_len().

Signed-off-by: Leo Yan <leo.yan@xxxxxxxxxx>
---
 .../util/arm-spe-decoder/arm-spe-pkt-decoder.c | 18 +++++++++---------
 .../util/arm-spe-decoder/arm-spe-pkt-decoder.h |  3 +++
 2 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
index 7c7b5eb09fba..4294c133a465 100644
--- a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
+++ b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
@@ -69,22 +69,22 @@ const char *arm_spe_pkt_name(enum arm_spe_pkt_type type)
 	return arm_spe_packet_name[type];
 }
 
-/* return ARM SPE payload size from its encoding,
- * which is in bits 5:4 of the byte.
- * 00 : byte
- * 01 : halfword (2)
- * 10 : word (4)
- * 11 : doubleword (8)
+/*
+ * Extracts the field "sz" from header bits and converts to bytes:
+ *   00 : byte (1)
+ *   01 : halfword (2)
+ *   10 : word (4)
+ *   11 : doubleword (8)
  */
-static int payloadlen(unsigned char byte)
+static unsigned int arm_spe_payload_len(unsigned char hdr)
 {
-	return 1 << ((byte & 0x30) >> 4);
+	return 1 << SPE_HEADER_SZ(hdr);
 }
 
 static int arm_spe_get_payload(const unsigned char *buf, size_t len,
 			       struct arm_spe_pkt *packet)
 {
-	size_t payload_len = payloadlen(buf[0]);
+	size_t payload_len = arm_spe_payload_len(buf[0]);
 
 	if (len < 1 + payload_len)
 		return ARM_SPE_NEED_MORE_BYTES;
diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.h b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.h
index 4c870521b8eb..e9ea8e3ead5d 100644
--- a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.h
+++ b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.h
@@ -9,6 +9,7 @@
 
 #include <stddef.h>
 #include <stdint.h>
+#include <linux/bits.h>
 
 #define ARM_SPE_PKT_DESC_MAX		256
 
@@ -36,6 +37,8 @@ struct arm_spe_pkt {
 	uint64_t		payload;
 };
 
+#define SPE_HEADER_SZ(val)			((val & GENMASK_ULL(5, 4)) >> 4)
+
 #define SPE_ADDR_PKT_HDR_INDEX_INS		(0x0)
 #define SPE_ADDR_PKT_HDR_INDEX_BRANCH		(0x1)
 #define SPE_ADDR_PKT_HDR_INDEX_DATA_VIRT	(0x2)
-- 
2.17.1