[PATCH v9 0/3] perf: cs-etm: Update perf to handle new Coresight Trace ID

[PATCH v9 0/3] perf: cs-etm: Update perf to handle new Coresight Trace ID

[Mike Leach]

The original method for allocating trace source ID values to sources was
to use a fixed algorithm for CPU based sources of (cpu_num * 2 + 0x10).
The STM was allocated ID 0x1.

This mechanism is broken for systems with more than 47 cores.

The kernel related patches the provide a fixed Trace ID allocation mechanism
are now upstreamed.

This patchset updates the perf code to handle the changes to the trace ID
notification mechanism that now uses the PERF_RECORD_AUX_OUTPUT_HW_ID
packet to set Trace ID in the perf ETM decoders.

Applies and test oo perf/core

Changes since v8:
1. Fix build issues
2. Fix implicit function problem

Changes since v7:
Split from original patchset [1] to be sent separately as kernel related
patches are now upstream.

[1] https://lore.kernel.org/linux-arm-kernel/20230116124928.5440-1-mike.leach@linaro.org/

Mike Leach (3):
  perf: cs-etm: Move mapping of Trace ID and cpu into helper function
  perf: cs-etm: Update record event to use new Trace ID protocol
  perf: cs-etm: Handle PERF_RECORD_AUX_OUTPUT_HW_ID packet

 tools/include/linux/coresight-pmu.h           |  47 ++-
 tools/perf/arch/arm/util/cs-etm.c             |  27 +-
 tools/perf/util/cs-etm-base.c                 |   3 +-
 .../perf/util/cs-etm-decoder/cs-etm-decoder.c |   7 +
 tools/perf/util/cs-etm.c                      | 326 +++++++++++++++---
 tools/perf/util/cs-etm.h                      |  14 +-
 6 files changed, 356 insertions(+), 68 deletions(-)

-- 
2.17.1

[PATCH v9 1/3] perf: cs-etm: Move mapping of Trace ID and cpu into helper function

[Mike Leach]

The information to associate Trace ID and CPU will be changing.

Drivers will start outputting this as a hardware ID packet in the data
file which if present will be used in preference to the AUXINFO values.

To prepare for this we provide a helper functions to do the individual ID
mapping, and one to extract the IDs from the completed metadata blocks.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: James Clark <james.clark@arm.com>
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 tools/include/linux/coresight-pmu.h |  5 ++
 tools/perf/util/cs-etm-base.c       |  3 +-
 tools/perf/util/cs-etm.c            | 92 +++++++++++++++++++----------
 tools/perf/util/cs-etm.h            | 14 ++++-
 4 files changed, 79 insertions(+), 35 deletions(-)

diff --git a/tools/include/linux/coresight-pmu.h b/tools/include/linux/coresight-pmu.h
index 6c2fd6cc5a98..db9c7c0abb6a 100644
--- a/tools/include/linux/coresight-pmu.h
+++ b/tools/include/linux/coresight-pmu.h
@@ -7,9 +7,14 @@
 #ifndef _LINUX_CORESIGHT_PMU_H
 #define _LINUX_CORESIGHT_PMU_H
 
+#include <linux/bits.h>
+
 #define CORESIGHT_ETM_PMU_NAME "cs_etm"
 #define CORESIGHT_ETM_PMU_SEED  0x10
 
+/* CoreSight trace ID is currently the bottom 7 bits of the value */
+#define CORESIGHT_TRACE_ID_VAL_MASK	GENMASK(6, 0)
+
 /*
  * Below are the definition of bit offsets for perf option, and works as
  * arbitrary values for all ETM versions.
diff --git a/tools/perf/util/cs-etm-base.c b/tools/perf/util/cs-etm-base.c
index 5f48b756c4cf..4abe416e3feb 100644
--- a/tools/perf/util/cs-etm-base.c
+++ b/tools/perf/util/cs-etm-base.c
@@ -148,7 +148,8 @@ static void cs_etm__print_auxtrace_info(u64 *val, int num)
 	for (i = CS_HEADER_VERSION_MAX; cpu < num; cpu++) {
 		if (version == 0)
 			err = cs_etm__print_cpu_metadata_v0(val, &i);
-		else if (version == 1)
+		/* printing same for both, but value bit flags added on v2 */
+		else if ((version == 1) || (version == 2))
 			err = cs_etm__print_cpu_metadata_v1(val, &i);
 		if (err)
 			return;
diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index f65bac5ddbdb..5fc9c288080b 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -196,6 +196,30 @@ int cs_etm__get_pid_fmt(u8 trace_chan_id, u64 *pid_fmt)
 	return 0;
 }
 
+static int cs_etm__map_trace_id(u8 trace_chan_id, u64 *cpu_metadata)
+{
+	struct int_node *inode;
+
+	/* Get an RB node for this CPU */
+	inode = intlist__findnew(traceid_list, trace_chan_id);
+
+	/* Something went wrong, no need to continue */
+	if (!inode)
+		return -ENOMEM;
+
+	/*
+	 * The node for that CPU should not be taken.
+	 * Back out if that's the case.
+	 */
+	if (inode->priv)
+		return -EINVAL;
+
+	/* All good, associate the traceID with the metadata pointer */
+	inode->priv = cpu_metadata;
+
+	return 0;
+}
+
 void cs_etm__etmq_set_traceid_queue_timestamp(struct cs_etm_queue *etmq,
 					      u8 trace_chan_id)
 {
@@ -2804,17 +2828,46 @@ static bool cs_etm__has_virtual_ts(u64 **metadata, int num_cpu)
 	return true;
 }
 
+/* map trace ids to correct metadata block, from information in metadata */
+static int cs_etm__map_trace_ids_metadata(int num_cpu, u64 **metadata)
+{
+	u64 cs_etm_magic;
+	u8 trace_chan_id;
+	int i, err;
+
+	for (i = 0; i < num_cpu; i++) {
+		cs_etm_magic = metadata[i][CS_ETM_MAGIC];
+		switch (cs_etm_magic) {
+		case __perf_cs_etmv3_magic:
+			trace_chan_id = (u8)((metadata[i][CS_ETM_ETMTRACEIDR]) &
+					     CORESIGHT_TRACE_ID_VAL_MASK);
+			break;
+		case __perf_cs_etmv4_magic:
+		case __perf_cs_ete_magic:
+			trace_chan_id = (u8)((metadata[i][CS_ETMV4_TRCTRACEIDR]) &
+					      CORESIGHT_TRACE_ID_VAL_MASK);
+			break;
+		default:
+			/* unknown magic number */
+			return -EINVAL;
+		}
+		err = cs_etm__map_trace_id(trace_chan_id, metadata[i]);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
 int cs_etm__process_auxtrace_info_full(union perf_event *event,
 				       struct perf_session *session)
 {
 	struct perf_record_auxtrace_info *auxtrace_info = &event->auxtrace_info;
 	struct cs_etm_auxtrace *etm = NULL;
-	struct int_node *inode;
 	struct perf_record_time_conv *tc = &session->time_conv;
 	int event_header_size = sizeof(struct perf_event_header);
 	int total_size = auxtrace_info->header.size;
 	int priv_size = 0;
-	int num_cpu, trcidr_idx;
+	int num_cpu;
 	int err = 0;
 	int i, j;
 	u64 *ptr = NULL;
@@ -2853,23 +2906,13 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event,
 				cs_etm__create_meta_blk(ptr, &i,
 							CS_ETM_PRIV_MAX,
 							CS_ETM_NR_TRC_PARAMS_V0);
-
-			/* The traceID is our handle */
-			trcidr_idx = CS_ETM_ETMTRACEIDR;
-
 		} else if (ptr[i] == __perf_cs_etmv4_magic) {
 			metadata[j] =
 				cs_etm__create_meta_blk(ptr, &i,
 							CS_ETMV4_PRIV_MAX,
 							CS_ETMV4_NR_TRC_PARAMS_V0);
-
-			/* The traceID is our handle */
-			trcidr_idx = CS_ETMV4_TRCTRACEIDR;
 		} else if (ptr[i] == __perf_cs_ete_magic) {
 			metadata[j] = cs_etm__create_meta_blk(ptr, &i, CS_ETE_PRIV_MAX, -1);
-
-			/* ETE shares first part of metadata with ETMv4 */
-			trcidr_idx = CS_ETMV4_TRCTRACEIDR;
 		} else {
 			ui__error("CS ETM Trace: Unrecognised magic number %#"PRIx64". File could be from a newer version of perf.\n",
 				  ptr[i]);
@@ -2881,26 +2924,6 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event,
 			err = -ENOMEM;
 			goto err_free_metadata;
 		}
-
-		/* Get an RB node for this CPU */
-		inode = intlist__findnew(traceid_list, metadata[j][trcidr_idx]);
-
-		/* Something went wrong, no need to continue */
-		if (!inode) {
-			err = -ENOMEM;
-			goto err_free_metadata;
-		}
-
-		/*
-		 * The node for that CPU should not be taken.
-		 * Back out if that's the case.
-		 */
-		if (inode->priv) {
-			err = -EINVAL;
-			goto err_free_metadata;
-		}
-		/* All good, associate the traceID with the metadata pointer */
-		inode->priv = metadata[j];
 	}
 
 	/*
@@ -2994,6 +3017,11 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event,
 	if (err)
 		goto err_delete_thread;
 
+	/* before aux records are queued, need to map metadata to trace IDs */
+	err = cs_etm__map_trace_ids_metadata(num_cpu, metadata);
+	if (err)
+		goto err_delete_thread;
+
 	err = cs_etm__queue_aux_records(session);
 	if (err)
 		goto err_delete_thread;
diff --git a/tools/perf/util/cs-etm.h b/tools/perf/util/cs-etm.h
index 98a4f7113d2f..661f029322e4 100644
--- a/tools/perf/util/cs-etm.h
+++ b/tools/perf/util/cs-etm.h
@@ -29,13 +29,17 @@ enum {
 /*
  * Update the version for new format.
  *
- * New version 1 format adds a param count to the per cpu metadata.
+ * Version 1: format adds a param count to the per cpu metadata.
  * This allows easy adding of new metadata parameters.
  * Requires that new params always added after current ones.
  * Also allows client reader to handle file versions that are different by
  * checking the number of params in the file vs the number expected.
+ *
+ * Version 2: Drivers will use PERF_RECORD_AUX_OUTPUT_HW_ID to output
+ * CoreSight Trace ID. ...TRACEIDR metadata will be set to legacy values
+ * but with addition flags.
  */
-#define CS_HEADER_CURRENT_VERSION 1
+#define CS_HEADER_CURRENT_VERSION	2
 
 /* Beginning of header common to both ETMv3 and V4 */
 enum {
@@ -97,6 +101,12 @@ enum {
 	CS_ETE_PRIV_MAX
 };
 
+/*
+ * Check for valid CoreSight trace ID. If an invalid value is present in the metadata,
+ * then IDs are present in the hardware ID packet in the data file.
+ */
+#define CS_IS_VALID_TRACE_ID(id) ((id > 0) && (id < 0x70))
+
 /*
  * ETMv3 exception encoding number:
  * See Embedded Trace Macrocell specification (ARM IHI 0014Q)
-- 
2.17.1

[PATCH v9 2/3] perf: cs-etm: Update record event to use new Trace ID protocol

[Mike Leach]

Trace IDs are now dynamically allocated.

Previously used the static association algorithm that is no longer
used. The 'cpu * 2 + seed' was outdated and broken for systems with high
core counts (>46). as it did not scale and was broken for larger
core counts.

Trace ID will now be sent in PERF_RECORD_AUX_OUTPUT_HW_ID record.

Legacy ID algorithm renamed and retained for limited backward
compatibility use.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: James Clark <james.clark@arm.com>
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 tools/include/linux/coresight-pmu.h | 29 +++++++++++++++++------------
 tools/perf/arch/arm/util/cs-etm.c   | 27 +++++++++++++++++----------
 2 files changed, 34 insertions(+), 22 deletions(-)

diff --git a/tools/include/linux/coresight-pmu.h b/tools/include/linux/coresight-pmu.h
index db9c7c0abb6a..1760f9a574b0 100644
--- a/tools/include/linux/coresight-pmu.h
+++ b/tools/include/linux/coresight-pmu.h
@@ -10,11 +10,27 @@
 #include <linux/bits.h>
 
 #define CORESIGHT_ETM_PMU_NAME "cs_etm"
-#define CORESIGHT_ETM_PMU_SEED  0x10
+
+/*
+ * The legacy Trace ID system based on fixed calculation from the cpu
+ * number. This has been replaced by drivers using a dynamic allocation
+ * system - but need to retain the legacy algorithm for backward comparibility
+ * in certain situations:-
+ * a) new perf running on older systems that generate the legacy mapping
+ * b) older tools that may not update at the same time as the kernel.
+ */
+#define CORESIGHT_LEGACY_CPU_TRACE_ID(cpu)  (0x10 + (cpu * 2))
 
 /* CoreSight trace ID is currently the bottom 7 bits of the value */
 #define CORESIGHT_TRACE_ID_VAL_MASK	GENMASK(6, 0)
 
+/*
+ * perf record will set the legacy meta data values as unused initially.
+ * This allows perf report to manage the decoders created when dynamic
+ * allocation in operation.
+ */
+#define CORESIGHT_TRACE_ID_UNUSED_FLAG	BIT(31)
+
 /*
  * Below are the definition of bit offsets for perf option, and works as
  * arbitrary values for all ETM versions.
@@ -39,15 +55,4 @@
 #define ETM4_CFG_BIT_RETSTK	12
 #define ETM4_CFG_BIT_VMID_OPT	15
 
-static inline int coresight_get_trace_id(int cpu)
-{
-	/*
-	 * A trace ID of value 0 is invalid, so let's start at some
-	 * random value that fits in 7 bits and go from there.  Since
-	 * the common convention is to have data trace IDs be I(N) + 1,
-	 * set instruction trace IDs as a function of the CPU number.
-	 */
-	return (CORESIGHT_ETM_PMU_SEED + (cpu * 2));
-}
-
 #endif
diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c
index 86b61ad74f90..e02a9bfc3d42 100644
--- a/tools/perf/arch/arm/util/cs-etm.c
+++ b/tools/perf/arch/arm/util/cs-etm.c
@@ -437,13 +437,16 @@ static int cs_etm_recording_options(struct auxtrace_record *itr,
 	evlist__to_front(evlist, cs_etm_evsel);
 
 	/*
-	 * In the case of per-cpu mmaps, we need the CPU on the
-	 * AUX event.  We also need the contextID in order to be notified
+	 * get the CPU on the sample - need it to associate trace ID in the
+	 * AUX_OUTPUT_HW_ID event, and the AUX event for per-cpu mmaps.
+	 */
+	evsel__set_sample_bit(cs_etm_evsel, CPU);
+
+	/*
+	 * Also the case of per-cpu mmaps, need the contextID in order to be notified
 	 * when a context switch happened.
 	 */
 	if (!perf_cpu_map__empty(cpus)) {
-		evsel__set_sample_bit(cs_etm_evsel, CPU);
-
 		err = cs_etm_set_option(itr, cs_etm_evsel,
 					BIT(ETM_OPT_CTXTID) | BIT(ETM_OPT_TS));
 		if (err)
@@ -679,8 +682,10 @@ static void cs_etm_save_etmv4_header(__u64 data[], struct auxtrace_record *itr,
 
 	/* Get trace configuration register */
 	data[CS_ETMV4_TRCCONFIGR] = cs_etmv4_get_config(itr);
-	/* Get traceID from the framework */
-	data[CS_ETMV4_TRCTRACEIDR] = coresight_get_trace_id(cpu);
+	/* traceID set to legacy version, in case new perf running on older system */
+	data[CS_ETMV4_TRCTRACEIDR] =
+		CORESIGHT_LEGACY_CPU_TRACE_ID(cpu) | CORESIGHT_TRACE_ID_UNUSED_FLAG;
+
 	/* Get read-only information from sysFS */
 	data[CS_ETMV4_TRCIDR0] = cs_etm_get_ro(cs_etm_pmu, cpu,
 					       metadata_etmv4_ro[CS_ETMV4_TRCIDR0]);
@@ -711,8 +716,10 @@ static void cs_etm_save_ete_header(__u64 data[], struct auxtrace_record *itr, in
 
 	/* Get trace configuration register */
 	data[CS_ETE_TRCCONFIGR] = cs_etmv4_get_config(itr);
-	/* Get traceID from the framework */
-	data[CS_ETE_TRCTRACEIDR] = coresight_get_trace_id(cpu);
+	/* traceID set to legacy version, in case new perf running on older system */
+	data[CS_ETE_TRCTRACEIDR] =
+		CORESIGHT_LEGACY_CPU_TRACE_ID(cpu) | CORESIGHT_TRACE_ID_UNUSED_FLAG;
+
 	/* Get read-only information from sysFS */
 	data[CS_ETE_TRCIDR0] = cs_etm_get_ro(cs_etm_pmu, cpu,
 					     metadata_ete_ro[CS_ETE_TRCIDR0]);
@@ -768,9 +775,9 @@ static void cs_etm_get_metadata(int cpu, u32 *offset,
 		magic = __perf_cs_etmv3_magic;
 		/* Get configuration register */
 		info->priv[*offset + CS_ETM_ETMCR] = cs_etm_get_config(itr);
-		/* Get traceID from the framework */
+		/* traceID set to legacy value in case new perf running on old system */
 		info->priv[*offset + CS_ETM_ETMTRACEIDR] =
-						coresight_get_trace_id(cpu);
+			CORESIGHT_LEGACY_CPU_TRACE_ID(cpu) | CORESIGHT_TRACE_ID_UNUSED_FLAG;
 		/* Get read-only information from sysFS */
 		info->priv[*offset + CS_ETM_ETMCCER] =
 			cs_etm_get_ro(cs_etm_pmu, cpu,
-- 
2.17.1

[PATCH v9 3/3] perf: cs-etm: Handle PERF_RECORD_AUX_OUTPUT_HW_ID packet

[Mike Leach]

When using dynamically assigned CoreSight trace IDs the drivers can output
the ID / CPU association as a PERF_RECORD_AUX_OUTPUT_HW_ID packet.

Update cs-etm decoder to handle this packet by setting the CPU/Trace ID
mapping.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: James Clark <james.clark@arm.com>
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 tools/include/linux/coresight-pmu.h           |  15 ++
 .../perf/util/cs-etm-decoder/cs-etm-decoder.c |   7 +
 tools/perf/util/cs-etm.c                      | 246 ++++++++++++++++--
 3 files changed, 250 insertions(+), 18 deletions(-)

diff --git a/tools/include/linux/coresight-pmu.h b/tools/include/linux/coresight-pmu.h
index 1760f9a574b0..cef3b1c25335 100644
--- a/tools/include/linux/coresight-pmu.h
+++ b/tools/include/linux/coresight-pmu.h
@@ -31,6 +31,9 @@
  */
 #define CORESIGHT_TRACE_ID_UNUSED_FLAG	BIT(31)
 
+/* Value to set for unused trace ID values */
+#define CORESIGHT_TRACE_ID_UNUSED_VAL	0x7F
+
 /*
  * Below are the definition of bit offsets for perf option, and works as
  * arbitrary values for all ETM versions.
@@ -55,4 +58,16 @@
 #define ETM4_CFG_BIT_RETSTK	12
 #define ETM4_CFG_BIT_VMID_OPT	15
 
+/*
+ * Interpretation of the PERF_RECORD_AUX_OUTPUT_HW_ID payload.
+ * Used to associate a CPU with the CoreSight Trace ID.
+ * [07:00] - Trace ID - uses 8 bits to make value easy to read in file.
+ * [59:08] - Unused (SBZ)
+ * [63:60] - Version
+ */
+#define CS_AUX_HW_ID_TRACE_ID_MASK	GENMASK_ULL(7, 0)
+#define CS_AUX_HW_ID_VERSION_MASK	GENMASK_ULL(63, 60)
+
+#define CS_AUX_HW_ID_CURR_VERSION 0
+
 #endif
diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
index d0e521dfcf35..82a27ab90c8b 100644
--- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
+++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
@@ -668,6 +668,7 @@ cs_etm_decoder__create_etm_decoder(struct cs_etm_decoder_params *d_params,
 	switch (t_params->protocol) {
 	case CS_ETM_PROTO_ETMV3:
 	case CS_ETM_PROTO_PTM:
+		csid = (t_params->etmv3.reg_idr & CORESIGHT_TRACE_ID_VAL_MASK);
 		cs_etm_decoder__gen_etmv3_config(t_params, &config_etmv3);
 		decoder->decoder_name = (t_params->protocol == CS_ETM_PROTO_ETMV3) ?
 							OCSD_BUILTIN_DCD_ETMV3 :
@@ -675,11 +676,13 @@ cs_etm_decoder__create_etm_decoder(struct cs_etm_decoder_params *d_params,
 		trace_config = &config_etmv3;
 		break;
 	case CS_ETM_PROTO_ETMV4i:
+		csid = (t_params->etmv4.reg_traceidr & CORESIGHT_TRACE_ID_VAL_MASK);
 		cs_etm_decoder__gen_etmv4_config(t_params, &trace_config_etmv4);
 		decoder->decoder_name = OCSD_BUILTIN_DCD_ETMV4I;
 		trace_config = &trace_config_etmv4;
 		break;
 	case CS_ETM_PROTO_ETE:
+		csid = (t_params->ete.reg_traceidr & CORESIGHT_TRACE_ID_VAL_MASK);
 		cs_etm_decoder__gen_ete_config(t_params, &trace_config_ete);
 		decoder->decoder_name = OCSD_BUILTIN_DCD_ETE;
 		trace_config = &trace_config_ete;
@@ -688,6 +691,10 @@ cs_etm_decoder__create_etm_decoder(struct cs_etm_decoder_params *d_params,
 		return -1;
 	}
 
+	/* if the CPU has no trace ID associated, no decoder needed */
+	if (csid == CORESIGHT_TRACE_ID_UNUSED_VAL)
+		return 0;
+
 	if (d_params->operation == CS_ETM_OPERATION_DECODE) {
 		if (ocsd_dt_create_decoder(decoder->dcd_tree,
 					   decoder->decoder_name,
diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 5fc9c288080b..94e2d02009eb 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -220,6 +220,143 @@ static int cs_etm__map_trace_id(u8 trace_chan_id, u64 *cpu_metadata)
 	return 0;
 }
 
+static int cs_etm__metadata_get_trace_id(u8 *trace_chan_id, u64 *cpu_metadata)
+{
+	u64 cs_etm_magic = cpu_metadata[CS_ETM_MAGIC];
+
+	switch (cs_etm_magic) {
+	case __perf_cs_etmv3_magic:
+		*trace_chan_id = (u8)(cpu_metadata[CS_ETM_ETMTRACEIDR] &
+				      CORESIGHT_TRACE_ID_VAL_MASK);
+		break;
+	case __perf_cs_etmv4_magic:
+	case __perf_cs_ete_magic:
+		*trace_chan_id = (u8)(cpu_metadata[CS_ETMV4_TRCTRACEIDR] &
+				      CORESIGHT_TRACE_ID_VAL_MASK);
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/*
+ * update metadata trace ID from the value found in the AUX_HW_INFO packet.
+ * This will also clear the CORESIGHT_TRACE_ID_UNUSED_FLAG flag if present.
+ */
+static int cs_etm__metadata_set_trace_id(u8 trace_chan_id, u64 *cpu_metadata)
+{
+	u64 cs_etm_magic = cpu_metadata[CS_ETM_MAGIC];
+
+	switch (cs_etm_magic) {
+	case __perf_cs_etmv3_magic:
+		 cpu_metadata[CS_ETM_ETMTRACEIDR] = trace_chan_id;
+		break;
+	case __perf_cs_etmv4_magic:
+	case __perf_cs_ete_magic:
+		cpu_metadata[CS_ETMV4_TRCTRACEIDR] = trace_chan_id;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/*
+ * FIELD_GET (linux/bitfield.h) not available outside kernel code,
+ * and the header contains too many dependencies to just copy over,
+ * so roll our own based on the original
+ */
+#define __bf_shf(x) (__builtin_ffsll(x) - 1)
+#define FIELD_GET(_mask, _reg)						\
+	({								\
+		(typeof(_mask))(((_reg) & (_mask)) >> __bf_shf(_mask)); \
+	})
+
+/*
+ * Handle the PERF_RECORD_AUX_OUTPUT_HW_ID event.
+ *
+ * The payload associates the Trace ID and the CPU.
+ * The routine is tolerant of seeing multiple packets with the same association,
+ * but a CPU / Trace ID association changing during a session is an error.
+ */
+static int cs_etm__process_aux_output_hw_id(struct perf_session *session,
+					    union perf_event *event)
+{
+	struct cs_etm_auxtrace *etm;
+	struct perf_sample sample;
+	struct int_node *inode;
+	struct evsel *evsel;
+	u64 *cpu_data;
+	u64 hw_id;
+	int cpu, version, err;
+	u8 trace_chan_id, curr_chan_id;
+
+	/* extract and parse the HW ID */
+	hw_id = event->aux_output_hw_id.hw_id;
+	version = FIELD_GET(CS_AUX_HW_ID_VERSION_MASK, hw_id);
+	trace_chan_id = FIELD_GET(CS_AUX_HW_ID_TRACE_ID_MASK, hw_id);
+
+	/* check that we can handle this version */
+	if (version > CS_AUX_HW_ID_CURR_VERSION)
+		return -EINVAL;
+
+	/* get access to the etm metadata */
+	etm = container_of(session->auxtrace, struct cs_etm_auxtrace, auxtrace);
+	if (!etm || !etm->metadata)
+		return -EINVAL;
+
+	/* parse the sample to get the CPU */
+	evsel = evlist__event2evsel(session->evlist, event);
+	if (!evsel)
+		return -EINVAL;
+	err = evsel__parse_sample(evsel, event, &sample);
+	if (err)
+		return err;
+	cpu = sample.cpu;
+	if (cpu == -1) {
+		/* no CPU in the sample - possibly recorded with an old version of perf */
+		pr_err("CS_ETM: no CPU AUX_OUTPUT_HW_ID sample. Use compatible perf to record.");
+		return -EINVAL;
+	}
+
+	/* See if the ID is mapped to a CPU, and it matches the current CPU */
+	inode = intlist__find(traceid_list, trace_chan_id);
+	if (inode) {
+		cpu_data = inode->priv;
+		if ((int)cpu_data[CS_ETM_CPU] != cpu) {
+			pr_err("CS_ETM: map mismatch between HW_ID packet CPU and Trace ID\n");
+			return -EINVAL;
+		}
+
+		/* check that the mapped ID matches */
+		err = cs_etm__metadata_get_trace_id(&curr_chan_id, cpu_data);
+		if (err)
+			return err;
+		if (curr_chan_id != trace_chan_id) {
+			pr_err("CS_ETM: mismatch between CPU trace ID and HW_ID packet ID\n");
+			return -EINVAL;
+		}
+
+		/* mapped and matched - return OK */
+		return 0;
+	}
+
+	/* not one we've seen before - lets map it */
+	cpu_data = etm->metadata[cpu];
+	err = cs_etm__map_trace_id(trace_chan_id, cpu_data);
+	if (err)
+		return err;
+
+	/*
+	 * if we are picking up the association from the packet, need to plug
+	 * the correct trace ID into the metadata for setting up decoders later.
+	 */
+	err = cs_etm__metadata_set_trace_id(trace_chan_id, cpu_data);
+	return err;
+}
+
 void cs_etm__etmq_set_traceid_queue_timestamp(struct cs_etm_queue *etmq,
 					      u8 trace_chan_id)
 {
@@ -2668,11 +2805,16 @@ static int cs_etm__queue_aux_fragment(struct perf_session *session, off_t file_o
 	}
 
 	/*
-	 * In per-thread mode, CPU is set to -1, but TID will be set instead. See
-	 * auxtrace_mmap_params__set_idx(). Return 'not found' if neither CPU nor TID match.
+	 * In per-thread mode, auxtrace CPU is set to -1, but TID will be set instead. See
+	 * auxtrace_mmap_params__set_idx(). However, the sample AUX event will contain a
+	 * CPU as we set this always for the AUX_OUTPUT_HW_ID event.
+	 * So now compare only TIDs if auxtrace CPU is -1, and CPUs if auxtrace CPU is not -1.
+	 * Return 'not found' if mismatch.
 	 */
-	if ((auxtrace_event->cpu == (__u32) -1 && auxtrace_event->tid != sample->tid) ||
-			auxtrace_event->cpu != sample->cpu)
+	if (auxtrace_event->cpu == (__u32) -1) {
+		if (auxtrace_event->tid != sample->tid)
+			return 1;
+	} else if (auxtrace_event->cpu != sample->cpu)
 		return 1;
 
 	if (aux_event->flags & PERF_AUX_FLAG_OVERWRITE) {
@@ -2721,6 +2863,17 @@ static int cs_etm__queue_aux_fragment(struct perf_session *session, off_t file_o
 	return 1;
 }
 
+static int cs_etm__process_aux_hw_id_cb(struct perf_session *session, union perf_event *event,
+					u64 offset __maybe_unused, void *data __maybe_unused)
+{
+	/* look to handle PERF_RECORD_AUX_OUTPUT_HW_ID early to ensure decoders can be set up */
+	if (event->header.type == PERF_RECORD_AUX_OUTPUT_HW_ID) {
+		(*(int *)data)++; /* increment found count */
+		return cs_etm__process_aux_output_hw_id(session, event);
+	}
+	return 0;
+}
+
 static int cs_etm__queue_aux_records_cb(struct perf_session *session, union perf_event *event,
 					u64 offset __maybe_unused, void *data __maybe_unused)
 {
@@ -2839,13 +2992,13 @@ static int cs_etm__map_trace_ids_metadata(int num_cpu, u64 **metadata)
 		cs_etm_magic = metadata[i][CS_ETM_MAGIC];
 		switch (cs_etm_magic) {
 		case __perf_cs_etmv3_magic:
-			trace_chan_id = (u8)((metadata[i][CS_ETM_ETMTRACEIDR]) &
-					     CORESIGHT_TRACE_ID_VAL_MASK);
+			metadata[i][CS_ETM_ETMTRACEIDR] &= CORESIGHT_TRACE_ID_VAL_MASK;
+			trace_chan_id = (u8)(metadata[i][CS_ETM_ETMTRACEIDR]);
 			break;
 		case __perf_cs_etmv4_magic:
 		case __perf_cs_ete_magic:
-			trace_chan_id = (u8)((metadata[i][CS_ETMV4_TRCTRACEIDR]) &
-					      CORESIGHT_TRACE_ID_VAL_MASK);
+			metadata[i][CS_ETMV4_TRCTRACEIDR] &= CORESIGHT_TRACE_ID_VAL_MASK;
+			trace_chan_id = (u8)(metadata[i][CS_ETMV4_TRCTRACEIDR]);
 			break;
 		default:
 			/* unknown magic number */
@@ -2858,6 +3011,35 @@ static int cs_etm__map_trace_ids_metadata(int num_cpu, u64 **metadata)
 	return 0;
 }
 
+/*
+ * If we found AUX_HW_ID packets, then set any metadata marked as unused to the
+ * unused value to reduce the number of unneeded decoders created.
+ */
+static int cs_etm__clear_unused_trace_ids_metadata(int num_cpu, u64 **metadata)
+{
+	u64 cs_etm_magic;
+	int i;
+
+	for (i = 0; i < num_cpu; i++) {
+		cs_etm_magic = metadata[i][CS_ETM_MAGIC];
+		switch (cs_etm_magic) {
+		case __perf_cs_etmv3_magic:
+			if (metadata[i][CS_ETM_ETMTRACEIDR] & CORESIGHT_TRACE_ID_UNUSED_FLAG)
+				metadata[i][CS_ETM_ETMTRACEIDR] = CORESIGHT_TRACE_ID_UNUSED_VAL;
+			break;
+		case __perf_cs_etmv4_magic:
+		case __perf_cs_ete_magic:
+			if (metadata[i][CS_ETMV4_TRCTRACEIDR] & CORESIGHT_TRACE_ID_UNUSED_FLAG)
+				metadata[i][CS_ETMV4_TRCTRACEIDR] = CORESIGHT_TRACE_ID_UNUSED_VAL;
+			break;
+		default:
+			/* unknown magic number */
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+
 int cs_etm__process_auxtrace_info_full(union perf_event *event,
 				       struct perf_session *session)
 {
@@ -2869,6 +3051,7 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event,
 	int priv_size = 0;
 	int num_cpu;
 	int err = 0;
+	int aux_hw_id_found;
 	int i, j;
 	u64 *ptr = NULL;
 	u64 **metadata = NULL;
@@ -3017,8 +3200,43 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event,
 	if (err)
 		goto err_delete_thread;
 
-	/* before aux records are queued, need to map metadata to trace IDs */
-	err = cs_etm__map_trace_ids_metadata(num_cpu, metadata);
+	/*
+	 * Map Trace ID values to CPU metadata.
+	 *
+	 * Trace metadata will always contain Trace ID values from the legacy algorithm. If the
+	 * files has been recorded by a "new" perf updated to handle AUX_HW_ID then the metadata
+	 * ID value will also have the CORESIGHT_TRACE_ID_UNUSED_FLAG set.
+	 *
+	 * The updated kernel drivers that use AUX_HW_ID to sent Trace IDs will attempt to use
+	 * the same IDs as the old algorithm as far as is possible, unless there are clashes
+	 * in which case a different value will be used. This means an older perf may still
+	 * be able to record and read files generate on a newer system.
+	 *
+	 * For a perf able to interpret AUX_HW_ID packets we first check for the presence of
+	 * those packets. If they are there then the values will be mapped and plugged into
+	 * the metadata. We then set any remaining metadata values with the used flag to a
+	 * value CORESIGHT_TRACE_ID_UNUSED_VAL - which indicates no decoder is required.
+	 *
+	 * If no AUX_HW_ID packets are present - which means a file recorded on an old kernel
+	 * then we map Trace ID values to CPU directly from the metadata - clearing any unused
+	 * flags if present.
+	 */
+
+	/* first scan for AUX_OUTPUT_HW_ID records to map trace ID values to CPU metadata */
+	aux_hw_id_found = 0;
+	err = perf_session__peek_events(session, session->header.data_offset,
+					session->header.data_size,
+					cs_etm__process_aux_hw_id_cb, &aux_hw_id_found);
+	if (err)
+		goto err_delete_thread;
+
+	/* if HW ID found then clear any unused metadata ID values */
+	if (aux_hw_id_found)
+		err = cs_etm__clear_unused_trace_ids_metadata(num_cpu, metadata);
+	/* otherwise, this is a file with metadata values only, map from metadata */
+	else
+		err = cs_etm__map_trace_ids_metadata(num_cpu, metadata);
+
 	if (err)
 		goto err_delete_thread;
 
@@ -3027,14 +3245,6 @@ int cs_etm__process_auxtrace_info_full(union perf_event *event,
 		goto err_delete_thread;
 
 	etm->data_queued = etm->queues.populated;
-	/*
-	 * Print warning in pipe mode, see cs_etm__process_auxtrace_event() and
-	 * cs_etm__queue_aux_fragment() for details relating to limitations.
-	 */
-	if (!etm->data_queued)
-		pr_warning("CS ETM warning: Coresight decode and TRBE support requires random file access.\n"
-			   "Continuing with best effort decoding in piped mode.\n\n");
-
 	return 0;
 
 err_delete_thread:
-- 
2.17.1

Re: [PATCH v9 0/3] perf: cs-etm: Update perf to handle new Coresight Trace ID

[Arnaldo Carvalho de Melo]

Em Fri, Mar 31, 2023 at 06:56:42AM +0100, Mike Leach escreveu:
> The original method for allocating trace source ID values to sources was
> to use a fixed algorithm for CPU based sources of (cpu_num * 2 + 0x10).
> The STM was allocated ID 0x1.
> 
> This mechanism is broken for systems with more than 47 cores.
> 
> The kernel related patches the provide a fixed Trace ID allocation mechanism
> are now upstreamed.
> 
> This patchset updates the perf code to handle the changes to the trace ID
> notification mechanism that now uses the PERF_RECORD_AUX_OUTPUT_HW_ID
> packet to set Trace ID in the perf ETM decoders.
> 
> Applies and test oo perf/core

I'm keeping perf/core with the same contents as perf-tools-next, please
use perf-tools-next as in the future I'll stop using the old perf/core
name.

Applied, testing.

- Arnaldo
 
> Changes since v8:
> 1. Fix build issues
> 2. Fix implicit function problem
> 
> Changes since v7:
> Split from original patchset [1] to be sent separately as kernel related
> patches are now upstream.
> 
> [1] https://lore.kernel.org/linux-arm-kernel/20230116124928.5440-1-mike.leach@linaro.org/
> 
> Mike Leach (3):
>   perf: cs-etm: Move mapping of Trace ID and cpu into helper function
>   perf: cs-etm: Update record event to use new Trace ID protocol
>   perf: cs-etm: Handle PERF_RECORD_AUX_OUTPUT_HW_ID packet
> 
>  tools/include/linux/coresight-pmu.h           |  47 ++-
>  tools/perf/arch/arm/util/cs-etm.c             |  27 +-
>  tools/perf/util/cs-etm-base.c                 |   3 +-
>  .../perf/util/cs-etm-decoder/cs-etm-decoder.c |   7 +
>  tools/perf/util/cs-etm.c                      | 326 +++++++++++++++---
>  tools/perf/util/cs-etm.h                      |  14 +-
>  6 files changed, 356 insertions(+), 68 deletions(-)
> 
> -- 
> 2.17.1
> 

-- 

- Arnaldo