[PATCH v2 5/6] perf arm_spe: Decode Arm N1 IMPDEF events

[James Clark]

>From the TRM [1], N1 has one IMPDEF event which isn't covered by the
common list. Add a framework so that more cores can be added in the
future and that the N1 IMPDEF event can be decoded. Also increase the
size of the buffer because we're adding more strings and if it gets
truncated it falls back to a hex dump only.

[1]: https://developer.arm.com/documentation/100616/0401/Statistical-Profiling-Extension/implementation-defined-features-of-SPE
Suggested-by: Al Grant <al.grant@xxxxxxx>
Signed-off-by: James Clark <james.clark@xxxxxxxxxx>
---
 tools/perf/util/arm-spe-decoder/Build              |  2 ++
 .../util/arm-spe-decoder/arm-spe-pkt-decoder.c     | 39 +++++++++++++++++++++-
 .../util/arm-spe-decoder/arm-spe-pkt-decoder.h     |  2 +-
 3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/arm-spe-decoder/Build b/tools/perf/util/arm-spe-decoder/Build
index ab500e0efe24..97a298d1e279 100644
--- a/tools/perf/util/arm-spe-decoder/Build
+++ b/tools/perf/util/arm-spe-decoder/Build
@@ -1 +1,3 @@
 perf-util-y += arm-spe-pkt-decoder.o arm-spe-decoder.o
+
+CFLAGS_arm-spe-pkt-decoder.o += -I$(srctree)/tools/arch/arm64/include/ -I$(OUTPUT)arch/arm64/include/generated/
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 67ca356100e5..b74f887a48f2 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
@@ -15,6 +15,8 @@
 
 #include "arm-spe-pkt-decoder.h"
 
+#include "../../arm64/include/asm/cputype.h"
+
 static const char * const arm_spe_packet_name[] = {
 	[ARM_SPE_PAD]		= "PAD",
 	[ARM_SPE_END]		= "END",
@@ -308,6 +310,11 @@ static const struct ev_string common_ev_strings[] = {
 	{ .event = 0, .desc = NULL },
 };
 
+static const struct ev_string n1_event_strings[] = {
+	{ .event = 12, .desc = "LATE-PREFETCH" },
+	{ .event = 0, .desc = NULL },
+};
+
 static u64 print_event_list(int *err, char **buf, size_t *buf_len,
 			    const struct ev_string *ev_strings, u64 payload)
 {
@@ -319,6 +326,26 @@ static u64 print_event_list(int *err, char **buf, size_t *buf_len,
 	return payload;
 }
 
+struct event_print_handle {
+	const struct midr_range *midr_ranges;
+	const struct ev_string *ev_strings;
+};
+
+#define EV_PRINT(range, strings)			\
+	{					\
+		.midr_ranges = range,		\
+		.ev_strings = strings,	\
+	}
+
+static const struct midr_range n1_event_encoding_cpus[] = {
+	MIDR_ALL_VERSIONS(MIDR_NEOVERSE_N1),
+	{},
+};
+
+static const struct event_print_handle event_print_handles[] = {
+	EV_PRINT(n1_event_encoding_cpus, n1_event_strings),
+};
+
 static int arm_spe_pkt_desc_event(const struct arm_spe_pkt *packet,
 				  char *buf, size_t buf_len)
 {
@@ -326,7 +353,17 @@ static int arm_spe_pkt_desc_event(const struct arm_spe_pkt *packet,
 	int err = 0;
 
 	arm_spe_pkt_out_string(&err, &buf, &buf_len, "EV");
-	print_event_list(&err, &buf, &buf_len, common_ev_strings, payload);
+	payload = print_event_list(&err, &buf, &buf_len, common_ev_strings,
+				   payload);
+
+	/* Try to decode IMPDEF bits for known CPUs */
+	for (unsigned int i = 0; i < ARRAY_SIZE(event_print_handles); i++) {
+		if (is_midr_in_range_list(packet->midr,
+					  event_print_handles[i].midr_ranges))
+			payload = print_event_list(&err, &buf, &buf_len,
+						   event_print_handles[i].ev_strings,
+						   payload);
+	}
 
 	return err;
 }
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 a457821f3bcc..a3300bec4990 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
@@ -11,7 +11,7 @@
 #include <stddef.h>
 #include <stdint.h>
 
-#define ARM_SPE_PKT_DESC_MAX		256
+#define ARM_SPE_PKT_DESC_MAX		512
 
 #define ARM_SPE_NEED_MORE_BYTES		-1
 #define ARM_SPE_BAD_PACKET		-2

-- 
2.34.1