Subject: [PATCH 02/10] perf hisi-ptt: Fix PTT trace TLP Header parsing

From: Sizhe Liu <[email-masked]>
Date: Thu, 4 Jun 2026 15:49:57 +0800

The DW0 bit field layout of the hisi_ptt_4dw union does not match the
actual bit ordering in little-endian memory, causing incorrect field
extraction. Reorder the struct members from LSB to MSB to match the
le32_to_cpu() conversion.

Also print all DW hex values in big-endian byte order for readability,
matching the bit field layout shown in the format diagram.

4DW format is like:
bits [31:30] [ 29:25 ][24][23][22][21][    20:11   ][    10:0    ]
     |-----|---------|---|---|---|---|-------------|-------------|
DW0  [ Fmt ][  Type  ][T9][T8][TH][SO][   Length   ][    Time    ]
DW1  [                     Header DW1                            ]
DW2  [                     Header DW2                            ]
DW3  [                     Header DW3                            ]

Cc: [email-masked]
Fixes: 5e91e57e6809 ("perf auxtrace arm64: Add support for parsing HiSilicon PCIe Trace packet")
Signed-off-by: Sizhe Liu <[email-masked]>
---
 Documentation/trace/hisi-ptt.rst              | 28 ++++++++--------
 .../hisi-ptt-decoder/hisi-ptt-pkt-decoder.c   | 33 ++++++++++++-------
 2 files changed, 35 insertions(+), 26 deletions(-)

diff --git a/Documentation/trace/hisi-ptt.rst b/Documentation/trace/hisi-ptt.rst
index 6eef28ebb0c7..f6a2655f99e5 100644
--- a/Documentation/trace/hisi-ptt.rst
+++ b/Documentation/trace/hisi-ptt.rst
@@ -285,20 +285,20 @@ according to the format described previously (take 8DW as an example):
     [...perf headers and other information]
     . ... HISI PTT data: size 4194304 bytes
     .  00000000: 00 00 00 00                                 Prefix
-    .  00000004: 01 00 00 60                                 Header DW0
-    .  00000008: 0f 1e 00 01                                 Header DW1
-    .  0000000c: 04 00 00 00                                 Header DW2
-    .  00000010: 40 00 81 02                                 Header DW3
-    .  00000014: 33 c0 04 00                                 Time
+    .  00000004: 60 00 00 01                                 Header DW0
+    .  00000008: 01 00 1e 0f                                 Header DW1
+    .  0000000c: 00 00 00 04                                 Header DW2
+    .  00000010: 02 81 00 40                                 Header DW3
+    .  00000014: 00 04 c0 33                                 Time
     .  00000020: 00 00 00 00                                 Prefix
-    .  00000024: 01 00 00 60                                 Header DW0
-    .  00000028: 0f 1e 00 01                                 Header DW1
-    .  0000002c: 04 00 00 00                                 Header DW2
-    .  00000030: 40 00 81 02                                 Header DW3
-    .  00000034: 02 00 00 00                                 Time
+    .  00000024: 60 00 00 01                                 Header DW0
+    .  00000028: 01 00 1e 0f                                 Header DW1
+    .  0000002c: 00 00 00 04                                 Header DW2
+    .  00000030: 02 81 00 40                                 Header DW3
+    .  00000034: 00 00 00 02                                 Time
     .  00000040: 00 00 00 00                                 Prefix
-    .  00000044: 01 00 00 60                                 Header DW0
-    .  00000048: 0f 1e 00 01                                 Header DW1
-    .  0000004c: 04 00 00 00                                 Header DW2
-    .  00000050: 40 00 81 02                                 Header DW3
+    .  00000044: 60 00 00 01                                 Header DW0
+    .  00000048: 01 00 1e 0f                                 Header DW1
+    .  0000004c: 00 00 00 04                                 Header DW2
+    .  00000050: 02 81 00 40                                 Header DW3
     [...]
diff --git a/tools/perf/util/hisi-ptt-decoder/hisi-ptt-pkt-decoder.c b/tools/perf/util/hisi-ptt-decoder/hisi-ptt-pkt-decoder.c
index c48b2ce7c4a3..67024f18ebbb 100644
--- a/tools/perf/util/hisi-ptt-decoder/hisi-ptt-pkt-decoder.c
+++ b/tools/perf/util/hisi-ptt-decoder/hisi-ptt-pkt-decoder.c
@@ -11,6 +11,7 @@
 #include <byteswap.h>
 #include <linux/bitops.h>
 #include <stdarg.h>
+#include <linux/kernel.h>
 
 #include "../color.h"
 #include "hisi-ptt-pkt-decoder.h"
@@ -75,14 +76,14 @@ static const char * const hisi_ptt_4dw_pkt_field_name[] = {
 
 union hisi_ptt_4dw {
 	struct {
-		uint32_t format : 2;
-		uint32_t type : 5;
-		uint32_t t9 : 1;
-		uint32_t t8 : 1;
-		uint32_t th : 1;
-		uint32_t so : 1;
-		uint32_t len : 10;
 		uint32_t time : 11;
+		uint32_t len : 10;
+		uint32_t so : 1;
+		uint32_t th : 1;
+		uint32_t t8 : 1;
+		uint32_t t9 : 1;
+		uint32_t type : 5;
+		uint32_t format : 2;
 	};
 	uint32_t value;
 };
@@ -90,12 +91,17 @@ union hisi_ptt_4dw {
 static void hisi_ptt_print_pkt(const unsigned char *buf, int pos, const char *desc)
 {
 	const char *color = PERF_COLOR_BLUE;
+	uint32_t value;
+	uint8_t byte;
 	int i;
 
+	value = le32_to_cpu(*(__le32 *)(buf + pos));
 	printf(".");
 	color_fprintf(stdout, color, "  %08x: ", pos);
-	for (i = 0; i < HISI_PTT_FIELD_LENGTH; i++)
-		color_fprintf(stdout, color, "%02x ", buf[pos + i]);
+	for (i = 0; i < HISI_PTT_FIELD_LENGTH; i++) {
+		byte = (value >> (24 - i * 8)) & 0xFF;
+		color_fprintf(stdout, color, "%02x ", byte);
+	}
 	for (i = 0; i < HISI_PTT_MAX_SPACE_LEN; i++)
 		color_fprintf(stdout, color, "   ");
 	color_fprintf(stdout, color, "  %s\n", desc);
@@ -123,13 +129,16 @@ static void hisi_ptt_4dw_print_dw0(const unsigned char *buf, int pos)
 {
 	const char *color = PERF_COLOR_BLUE;
 	union hisi_ptt_4dw dw0;
+	uint8_t byte;
 	int i;
 
-	dw0.value = *(uint32_t *)(buf + pos);
+	dw0.value = le32_to_cpu(*(__le32 *)(buf + pos));
 	printf(".");
 	color_fprintf(stdout, color, "  %08x: ", pos);
-	for (i = 0; i < HISI_PTT_FIELD_LENGTH; i++)
-		color_fprintf(stdout, color, "%02x ", buf[pos + i]);
+	for (i = 0; i < HISI_PTT_FIELD_LENGTH; i++) {
+		byte = (dw0.value >> (24 - i * 8)) & 0xFF;
+		color_fprintf(stdout, color, "%02x ", byte);
+	}
 	for (i = 0; i < HISI_PTT_MAX_SPACE_LEN; i++)
 		color_fprintf(stdout, color, "   ");
 
-- 
2.33.0