[PATCH v6 00/14] coresight: Add new API to allocate trace source ID values

[PATCH v6 00/14] coresight: Add new API to allocate trace source ID values

[Mike Leach]

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

This fixed algorithm is used in both the CoreSight driver code, and by
perf when writing the trace metadata in the AUXTRACE_INFO record.

The method needs replacing as currently:-
1. It is inefficient in using available IDs.
2. Does not scale to larger systems with many cores and the algorithm
has no limits so will generate invalid trace IDs for cpu number > 44.

Additionally requirements to allocate additional system IDs on some
systems have been seen.

This patch set  introduces an API that allows the allocation of trace IDs
in a dynamic manner.

Architecturally reserved IDs are never allocated, and the system is
limited to allocating only valid IDs.

Each of the current trace sources ETM3.x, ETM4.x and STM is updated to use
the new API.

For the ETMx.x devices IDs are allocated on certain events
a) When using sysfs, an ID will be allocated on hardware enable, or a read of
sysfs TRCTRACEID register and freed when the sysfs reset is written.

b) When using perf, ID is allocated on during setup AUX event, and freed on
event free. IDs are communicated using the AUX_OUTPUT_HW_ID packet.
The ID allocator is notified when perf sessions start and stop
so CPU based IDs are kept constant throughout any perf session.


Note: This patchset breaks some backward compatibility for perf record and
perf report.

The version of the AUXTRACE_INFO has been updated to reflect the fact that
the trace source IDs are generated differently. This will
mean older versions of perf report cannot decode the newer file.

Appies to coresight/next

Changes since v5: (requested by suzuki)
1) Prefer odd ID values for system IDs to avoid overlap with legacy CPU IDs
2) Some style changes

Changes since v4:
1) update to ensure that compiling after each individual patch added still
works - ie. git bisect not broken through the patchset..

2) Revision to some of the now redundant code in cs-etm (James)

3) Comments and other minor fixes requested by Suzuki.

Changes since v3:
1) Fixed aarch32 build error in ETM3.x driver.
Reported-by: kernel test robot <lkp@intel.com>

Changes since v2:
1) Improved backward compatibility: (requested by James)

Using the new version of perf on an old kernel will generate a usable file
legacy metadata values are set by the new perf and will be used if mew
ID packets are not present in the file.

Using an older version of perf / simpleperf on an updated kernel may still
work. The trace ID allocator has been updated to use the legacy ID values
where possible, so generated file and used trace IDs will match up to the
point where the legacy algorithm is broken anyway.

2) Various changes to the ID allocator and ID packet format.
(suggested by Suzuki)

3) per CPU ID info in allocator now stored as atomic type to allow a passive read
without taking the allocator spinlock. perf flow now allocates and releases ID
values in setup_aux / free_event. Device enable and event enable use the passive
read to set the allocated values. This simplifies the locking mechanisms on the
perf run and fixes issues that arose with locking dependencies.

Changes since v1:
(after feedback & discussion with Mathieu & Suzuki).

1) API has changed. The global trace ID map is managed internally, so it
is no longer passed in to the API functions.

2) perf record does not use sysfs to find the trace IDs. These are now
output as AUX_OUTPUT_HW_ID events. The drivers, perf record, and perf report
have been updated accordingly to generate and handle these events.

Mike Leach (14):
  coresight: trace-id: Add API to dynamically assign Trace ID values
  coresight: Remove obsolete Trace ID unniqueness checks
  coresight: perf: traceid: Add perf ID allocation and notifiers
  coresight: stm: Update STM driver to use Trace ID API
  coresight: etm4x: Update ETM4 driver to use Trace ID API
  coresight: etm3x: Update ETM3 driver to use Trace ID API
  coresight: etmX.X: stm: Remove trace_id() callback
  coresight: trace id: Remove legacy get trace ID function.
  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
  kernel: events: Export perf_report_aux_output_id()
  perf: cs-etm: Handle PERF_RECORD_AUX_OUTPUT_HW_ID packet
  coresight: events: PERF_RECORD_AUX_OUTPUT_HW_ID used for Trace ID
  coresight: trace-id: Add debug & test macros to Trace ID allocation

 drivers/hwtracing/coresight/Makefile          |   2 +-
 drivers/hwtracing/coresight/coresight-core.c  |  45 ---
 .../hwtracing/coresight/coresight-etm-perf.c  |  23 ++
 drivers/hwtracing/coresight/coresight-etm.h   |   3 +-
 .../coresight/coresight-etm3x-core.c          |  93 +++--
 .../coresight/coresight-etm3x-sysfs.c         |  27 +-
 .../coresight/coresight-etm4x-core.c          |  73 +++-
 .../coresight/coresight-etm4x-sysfs.c         |  27 +-
 drivers/hwtracing/coresight/coresight-etm4x.h |   3 +
 drivers/hwtracing/coresight/coresight-stm.c   |  49 +--
 .../hwtracing/coresight/coresight-trace-id.c  | 298 ++++++++++++++++
 .../hwtracing/coresight/coresight-trace-id.h  | 156 +++++++++
 include/linux/coresight-pmu.h                 |  34 +-
 include/linux/coresight.h                     |   3 -
 kernel/events/core.c                          |   1 +
 tools/include/linux/coresight-pmu.h           |  48 ++-
 tools/perf/arch/arm/util/cs-etm.c             |  21 +-
 .../perf/util/cs-etm-decoder/cs-etm-decoder.c |   7 +
 tools/perf/util/cs-etm.c                      | 328 +++++++++++++++---
 tools/perf/util/cs-etm.h                      |  14 +-
 20 files changed, 1024 insertions(+), 231 deletions(-)
 create mode 100644 drivers/hwtracing/coresight/coresight-trace-id.c
 create mode 100644 drivers/hwtracing/coresight/coresight-trace-id.h

-- 
2.17.1

[PATCH v6 01/14] coresight: trace-id: Add API to dynamically assign Trace ID values

[Mike Leach]

The existing mechanism to assign Trace ID values to sources is limited
and does not scale for larger multicore / multi trace source systems.

The API introduces functions that reserve IDs based on availabilty
represented by a coresight_trace_id_map structure. This records the
used and free IDs in a bitmap.

CPU bound sources such as ETMs use the coresight_trace_id_get_cpu_id
coresight_trace_id_put_cpu_id pair of functions. The API will record
the ID associated with the CPU. This ensures that the same ID will be
re-used while perf events are active on the CPU. The put_cpu_id function
will pend release of the ID until all perf cs_etm sessions are complete.

For backward compatibility the functions will attempt to use the same
CPU IDs as the legacy system would have used if these are still available.

Non-cpu sources, such as the STM can use coresight_trace_id_get_system_id /
coresight_trace_id_put_system_id.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
---
 drivers/hwtracing/coresight/Makefile          |   2 +-
 .../hwtracing/coresight/coresight-trace-id.c  | 265 ++++++++++++++++++
 .../hwtracing/coresight/coresight-trace-id.h  | 156 +++++++++++
 include/linux/coresight-pmu.h                 |  10 +
 4 files changed, 432 insertions(+), 1 deletion(-)
 create mode 100644 drivers/hwtracing/coresight/coresight-trace-id.c
 create mode 100644 drivers/hwtracing/coresight/coresight-trace-id.h

diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
index b6c4a48140ec..329a0c704b87 100644
--- a/drivers/hwtracing/coresight/Makefile
+++ b/drivers/hwtracing/coresight/Makefile
@@ -6,7 +6,7 @@ obj-$(CONFIG_CORESIGHT) += coresight.o
 coresight-y := coresight-core.o  coresight-etm-perf.o coresight-platform.o \
 		coresight-sysfs.o coresight-syscfg.o coresight-config.o \
 		coresight-cfg-preload.o coresight-cfg-afdo.o \
-		coresight-syscfg-configfs.o
+		coresight-syscfg-configfs.o coresight-trace-id.o
 obj-$(CONFIG_CORESIGHT_LINK_AND_SINK_TMC) += coresight-tmc.o
 coresight-tmc-y := coresight-tmc-core.o coresight-tmc-etf.o \
 		      coresight-tmc-etr.o
diff --git a/drivers/hwtracing/coresight/coresight-trace-id.c b/drivers/hwtracing/coresight/coresight-trace-id.c
new file mode 100644
index 000000000000..9b85c376cb12
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-trace-id.c
@@ -0,0 +1,265 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022, Linaro Limited, All rights reserved.
+ * Author: Mike Leach <mike.leach@linaro.org>
+ */
+#include <linux/coresight-pmu.h>
+#include <linux/cpumask.h>
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+#include "coresight-trace-id.h"
+
+/* Default trace ID map. Used on systems that don't require per sink mappings */
+static struct coresight_trace_id_map id_map_default;
+
+/* maintain a record of the mapping of IDs and pending releases per cpu */
+static DEFINE_PER_CPU(atomic_t, cpu_id) = ATOMIC_INIT(0);
+static cpumask_t cpu_id_release_pending;
+
+/* perf session active counter */
+static atomic_t perf_cs_etm_session_active = ATOMIC_INIT(0);
+
+/* lock to protect id_map and cpu data  */
+static DEFINE_SPINLOCK(id_map_lock);
+
+/* unlocked read of current trace ID value for given CPU */
+static int _coresight_trace_id_read_cpu_id(int cpu)
+{
+	return atomic_read(&per_cpu(cpu_id, cpu));
+}
+
+/* look for next available odd ID, return 0 if none found */
+static int coresight_trace_id_find_odd_id(struct coresight_trace_id_map *id_map)
+{
+	int found_id = 0, bit = 1, next_id;
+
+	while ((bit < CORESIGHT_TRACE_ID_RES_TOP) && !found_id) {
+		/*
+		 * bitmap length of CORESIGHT_TRACE_ID_RES_TOP,
+		 * search from offset `bit`.
+		 */
+		next_id = find_next_zero_bit(id_map->used_ids,
+					     CORESIGHT_TRACE_ID_RES_TOP, bit);
+		if ((next_id < CORESIGHT_TRACE_ID_RES_TOP) && (next_id & 0x1))
+			found_id = next_id;
+		else
+			bit = next_id + 1;
+	}
+	return found_id;
+}
+
+/*
+ * Allocate new ID and set in use
+ *
+ * if @preferred_id is a valid id then try to use that value if available.
+ * if @preferred_id is not valid and @prefer_odd_id is true, try for odd id.
+ *
+ * Otherwise allocate next available ID.
+ */
+static int coresight_trace_id_alloc_new_id(struct coresight_trace_id_map *id_map,
+					   int preferred_id, bool prefer_odd_id)
+{
+	int id = 0;
+
+	/* for backwards compatibility, cpu IDs may use preferred value */
+	if (IS_VALID_CS_TRACE_ID(preferred_id) &&
+	    !test_bit(preferred_id, id_map->used_ids)) {
+		id = preferred_id;
+		goto trace_id_allocated;
+	} else if (prefer_odd_id) {
+	/* may use odd ids to avoid preferred legacy cpu IDs */
+		id = coresight_trace_id_find_odd_id(id_map);
+		if (id)
+			goto trace_id_allocated;
+	}
+
+	/*
+	 * skip reserved bit 0, look at bitmap length of
+	 * CORESIGHT_TRACE_ID_RES_TOP from offset of bit 1.
+	 */
+	id = find_next_zero_bit(id_map->used_ids, CORESIGHT_TRACE_ID_RES_TOP, 1);
+	if (id >= CORESIGHT_TRACE_ID_RES_TOP)
+		return -EINVAL;
+
+	/* mark as used */
+trace_id_allocated:
+	set_bit(id, id_map->used_ids);
+	return id;
+}
+
+static void coresight_trace_id_free(int id, struct coresight_trace_id_map *id_map)
+{
+	if (WARN(!IS_VALID_CS_TRACE_ID(id), "Invalid Trace ID %d\n", id))
+		return;
+	if (WARN(!test_bit(id, id_map->used_ids), "Freeing unused ID %d\n", id))
+		return;
+	clear_bit(id, id_map->used_ids);
+}
+
+static void coresight_trace_id_set_pend_rel(int id, struct coresight_trace_id_map *id_map)
+{
+	if (WARN(!IS_VALID_CS_TRACE_ID(id), "Invalid Trace ID %d\n", id))
+		return;
+	set_bit(id, id_map->pend_rel_ids);
+}
+
+/*
+ * release all pending IDs for all current maps & clear CPU associations
+ *
+ * This currently operates on the default id map, but may be extended to
+ * operate on all registered id maps if per sink id maps are used.
+ */
+static void coresight_trace_id_release_all_pending(void)
+{
+	struct coresight_trace_id_map *id_map = &id_map_default;
+	unsigned long flags;
+	int cpu, bit;
+
+	spin_lock_irqsave(&id_map_lock, flags);
+	for_each_set_bit(bit, id_map->pend_rel_ids, CORESIGHT_TRACE_ID_RES_TOP) {
+		clear_bit(bit, id_map->used_ids);
+		clear_bit(bit, id_map->pend_rel_ids);
+	}
+	for_each_cpu(cpu, &cpu_id_release_pending) {
+		atomic_set(&per_cpu(cpu_id, cpu), 0);
+		cpumask_clear_cpu(cpu, &cpu_id_release_pending);
+	}
+	spin_unlock_irqrestore(&id_map_lock, flags);
+}
+
+static int coresight_trace_id_map_get_cpu_id(int cpu, struct coresight_trace_id_map *id_map)
+{
+	unsigned long flags;
+	int id;
+
+	spin_lock_irqsave(&id_map_lock, flags);
+
+	/* check for existing allocation for this CPU */
+	id = _coresight_trace_id_read_cpu_id(cpu);
+	if (id)
+		goto get_cpu_id_clr_pend;
+
+	/*
+	 * Find a new ID.
+	 *
+	 * Use legacy values where possible in the dynamic trace ID allocator to
+	 * allow older tools to continue working if they are not upgraded at the
+	 * same time as the kernel drivers.
+	 *
+	 * If the generated legacy ID is invalid, or not available then the next
+	 * available dynamic ID will be used.
+	 */
+	id = coresight_trace_id_alloc_new_id(id_map,
+					     CORESIGHT_LEGACY_CPU_TRACE_ID(cpu),
+					     false);
+	if (!IS_VALID_CS_TRACE_ID(id))
+		goto get_cpu_id_out_unlock;
+
+	/* allocate the new id to the cpu */
+	atomic_set(&per_cpu(cpu_id, cpu), id);
+
+get_cpu_id_clr_pend:
+	/* we are (re)using this ID - so ensure it is not marked for release */
+	cpumask_clear_cpu(cpu, &cpu_id_release_pending);
+	clear_bit(id, id_map->pend_rel_ids);
+
+get_cpu_id_out_unlock:
+	spin_unlock_irqrestore(&id_map_lock, flags);
+
+	return id;
+}
+
+static void coresight_trace_id_map_put_cpu_id(int cpu, struct coresight_trace_id_map *id_map)
+{
+	unsigned long flags;
+	int id;
+
+	/* check for existing allocation for this CPU */
+	id = _coresight_trace_id_read_cpu_id(cpu);
+	if (!id)
+		return;
+
+	spin_lock_irqsave(&id_map_lock, flags);
+
+	if (atomic_read(&perf_cs_etm_session_active)) {
+		/* set release at pending if perf still active */
+		coresight_trace_id_set_pend_rel(id, id_map);
+		cpumask_set_cpu(cpu, &cpu_id_release_pending);
+	} else {
+		/* otherwise clear id */
+		coresight_trace_id_free(id, id_map);
+		atomic_set(&per_cpu(cpu_id, cpu), 0);
+	}
+
+	spin_unlock_irqrestore(&id_map_lock, flags);
+}
+
+static int coresight_trace_id_map_get_system_id(struct coresight_trace_id_map *id_map)
+{
+	unsigned long flags;
+	int id;
+
+	spin_lock_irqsave(&id_map_lock, flags);
+	/* prefer odd IDs for system components to avoid legacy CPU IDS */
+	id = coresight_trace_id_alloc_new_id(id_map, 0, true);
+	spin_unlock_irqrestore(&id_map_lock, flags);
+
+	return id;
+}
+
+static void coresight_trace_id_map_put_system_id(struct coresight_trace_id_map *id_map, int id)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&id_map_lock, flags);
+	coresight_trace_id_free(id, id_map);
+	spin_unlock_irqrestore(&id_map_lock, flags);
+}
+
+/* API functions */
+
+int coresight_trace_id_get_cpu_id(int cpu)
+{
+	return coresight_trace_id_map_get_cpu_id(cpu, &id_map_default);
+}
+EXPORT_SYMBOL_GPL(coresight_trace_id_get_cpu_id);
+
+void coresight_trace_id_put_cpu_id(int cpu)
+{
+	coresight_trace_id_map_put_cpu_id(cpu, &id_map_default);
+}
+EXPORT_SYMBOL_GPL(coresight_trace_id_put_cpu_id);
+
+int coresight_trace_id_read_cpu_id(int cpu)
+{
+	return _coresight_trace_id_read_cpu_id(cpu);
+}
+EXPORT_SYMBOL_GPL(coresight_trace_id_read_cpu_id);
+
+int coresight_trace_id_get_system_id(void)
+{
+	return coresight_trace_id_map_get_system_id(&id_map_default);
+}
+EXPORT_SYMBOL_GPL(coresight_trace_id_get_system_id);
+
+void coresight_trace_id_put_system_id(int id)
+{
+	coresight_trace_id_map_put_system_id(&id_map_default, id);
+}
+EXPORT_SYMBOL_GPL(coresight_trace_id_put_system_id);
+
+void coresight_trace_id_perf_start(void)
+{
+	atomic_inc(&perf_cs_etm_session_active);
+}
+EXPORT_SYMBOL_GPL(coresight_trace_id_perf_start);
+
+void coresight_trace_id_perf_stop(void)
+{
+	if (!atomic_dec_return(&perf_cs_etm_session_active))
+		coresight_trace_id_release_all_pending();
+}
+EXPORT_SYMBOL_GPL(coresight_trace_id_perf_stop);
+
diff --git a/drivers/hwtracing/coresight/coresight-trace-id.h b/drivers/hwtracing/coresight/coresight-trace-id.h
new file mode 100644
index 000000000000..3797777d367e
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-trace-id.h
@@ -0,0 +1,156 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright(C) 2022 Linaro Limited. All rights reserved.
+ * Author: Mike Leach <mike.leach@linaro.org>
+ */
+
+#ifndef _CORESIGHT_TRACE_ID_H
+#define _CORESIGHT_TRACE_ID_H
+
+/*
+ * Coresight trace ID allocation API
+ *
+ * With multi cpu systems, and more additional trace sources a scalable
+ * trace ID reservation system is required.
+ *
+ * The system will allocate Ids on a demand basis, and allow them to be
+ * released when done.
+ *
+ * In order to ensure that a consistent cpu / ID matching is maintained
+ * throughout a perf cs_etm event session - a session in progress flag will
+ * be maintained, and released IDs not cleared until the perf session is
+ * complete. This allows the same CPU to be re-allocated its prior ID.
+ *
+ *
+ * Trace ID maps will be created and initialised to prevent architecturally
+ * reserved IDs from being allocated.
+ *
+ * API permits multiple maps to be maintained - for large systems where
+ * different sets of cpus trace into different independent sinks.
+ */
+
+#include <linux/bitops.h>
+#include <linux/types.h>
+
+
+/* architecturally we have 128 IDs some of which are reserved */
+#define CORESIGHT_TRACE_IDS_MAX 128
+
+/* ID 0 is reserved */
+#define CORESIGHT_TRACE_ID_RES_0 0
+
+/* ID 0x70 onwards are reserved */
+#define CORESIGHT_TRACE_ID_RES_TOP 0x70
+
+/* check an ID is in the valid range */
+#define IS_VALID_CS_TRACE_ID(id)	\
+	((id > CORESIGHT_TRACE_ID_RES_0) && (id < CORESIGHT_TRACE_ID_RES_TOP))
+
+/**
+ * Trace ID map.
+ *
+ * @used_ids:	Bitmap to register available (bit = 0) and in use (bit = 1) IDs.
+ *		Initialised so that the reserved IDs are permanently marked as
+ *		in use.
+ * @pend_rel_ids: CPU IDs that have been released by the trace source but not
+ *		  yet marked as available, to allow re-allocation to the same
+ *		  CPU during a perf session.
+ */
+struct coresight_trace_id_map {
+	DECLARE_BITMAP(used_ids, CORESIGHT_TRACE_IDS_MAX);
+	DECLARE_BITMAP(pend_rel_ids, CORESIGHT_TRACE_IDS_MAX);
+};
+
+/* Allocate and release IDs for a single default trace ID map */
+
+/**
+ * Read and optionally allocate a CoreSight trace ID and associate with a CPU.
+ *
+ * Function will read the current trace ID for the associated CPU,
+ * allocating an new ID if one is not currently allocated.
+ *
+ * Numeric ID values allocated use legacy allocation algorithm if possible,
+ * otherwise any available ID is used.
+ *
+ * @cpu: The CPU index to allocate for.
+ *
+ * return: CoreSight trace ID or -EINVAL if allocation impossible.
+ */
+int coresight_trace_id_get_cpu_id(int cpu);
+
+/**
+ * Release an allocated trace ID associated with the CPU.
+ *
+ * This will release the CoreSight trace ID associated with the CPU,
+ * unless a perf session is in operation.
+ *
+ * If a perf session is in operation then the ID will be marked as pending
+ * release.
+ *
+ * @cpu: The CPU index to release the associated trace ID.
+ */
+void coresight_trace_id_put_cpu_id(int cpu);
+
+/**
+ * Read the current allocated CoreSight Trace ID value for the CPU.
+ *
+ * Fast read of the current value that does not allocate if no ID allocated
+ * for the CPU.
+ *
+ * Used in perf context  where it is known that the value for the CPU will not
+ * be changing, when perf starts and event on a core and outputs the Trace ID
+ * for the CPU as a packet in the data file. IDs cannot change during a perf
+ * session.
+ *
+ * This function does not take the lock protecting the ID lists, avoiding
+ * locking dependency issues with perf locks.
+ *
+ * @cpu: The CPU index to read.
+ *
+ * return: current value, will be 0 if unallocated.
+ */
+int coresight_trace_id_read_cpu_id(int cpu);
+
+/**
+ * Allocate a CoreSight trace ID for a system component.
+ *
+ * Unconditionally allocates a Trace ID, without associating the ID with a CPU.
+ *
+ * Used to allocate IDs for system trace sources such as STM.
+ *
+ * return: Trace ID or -EINVAL if allocation is impossible.
+ */
+int coresight_trace_id_get_system_id(void);
+
+/**
+ * Release an allocated system trace ID.
+ *
+ * Unconditionally release a trace ID allocated to a system component.
+ *
+ * @id: value of trace ID allocated.
+ */
+void coresight_trace_id_put_system_id(int id);
+
+/* notifiers for perf session start and stop */
+
+/**
+ * Notify the Trace ID allocator that a perf session is starting.
+ *
+ * Increase the perf session reference count - called by perf when setting up
+ * a trace event.
+ *
+ * This reference count is used by the ID allocator to ensure that trace IDs
+ * associated with a CPU cannot change or be released during a perf session.
+ */
+void coresight_trace_id_perf_start(void);
+
+/**
+ * Notify the ID allocator that a perf session is stopping.
+ *
+ * Decrease the perf session reference count.
+ * if this causes the count to go to zero, then all Trace IDs marked as pending
+ * release, will be released.
+ */
+void coresight_trace_id_perf_stop(void);
+
+#endif /* _CORESIGHT_TRACE_ID_H */
diff --git a/include/linux/coresight-pmu.h b/include/linux/coresight-pmu.h
index 6c2fd6cc5a98..ffff4e6277e5 100644
--- a/include/linux/coresight-pmu.h
+++ b/include/linux/coresight-pmu.h
@@ -10,6 +10,16 @@
 #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))
+
 /*
  * Below are the definition of bit offsets for perf option, and works as
  * arbitrary values for all ETM versions.
-- 
2.17.1

[PATCH v6 02/14] coresight: Remove obsolete Trace ID unniqueness checks

[Mike Leach]

The checks for sources to have unique IDs has been removed - this is now
guaranteed by the ID allocation mechanisms, and inappropriate where
multiple ID maps are in use in larger systems

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-core.c | 45 --------------------
 1 file changed, 45 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index f3068175ca9d..ce3aa845ecc2 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -112,45 +112,6 @@ struct coresight_device *coresight_get_percpu_sink(int cpu)
 }
 EXPORT_SYMBOL_GPL(coresight_get_percpu_sink);
 
-static int coresight_id_match(struct device *dev, void *data)
-{
-	int trace_id, i_trace_id;
-	struct coresight_device *csdev, *i_csdev;
-
-	csdev = data;
-	i_csdev = to_coresight_device(dev);
-
-	/*
-	 * No need to care about oneself and components that are not
-	 * sources or not enabled
-	 */
-	if (i_csdev == csdev || !i_csdev->enable ||
-	    i_csdev->type != CORESIGHT_DEV_TYPE_SOURCE)
-		return 0;
-
-	/* Get the source ID for both components */
-	trace_id = source_ops(csdev)->trace_id(csdev);
-	i_trace_id = source_ops(i_csdev)->trace_id(i_csdev);
-
-	/* All you need is one */
-	if (trace_id == i_trace_id)
-		return 1;
-
-	return 0;
-}
-
-static int coresight_source_is_unique(struct coresight_device *csdev)
-{
-	int trace_id = source_ops(csdev)->trace_id(csdev);
-
-	/* this shouldn't happen */
-	if (trace_id < 0)
-		return 0;
-
-	return !bus_for_each_dev(&coresight_bustype, NULL,
-				 csdev, coresight_id_match);
-}
-
 static int coresight_find_link_inport(struct coresight_device *csdev,
 				      struct coresight_device *parent)
 {
@@ -459,12 +420,6 @@ static int coresight_enable_source(struct coresight_device *csdev, u32 mode)
 {
 	int ret;
 
-	if (!coresight_source_is_unique(csdev)) {
-		dev_warn(&csdev->dev, "traceID %d not unique\n",
-			 source_ops(csdev)->trace_id(csdev));
-		return -EINVAL;
-	}
-
 	if (!csdev->enable) {
 		if (source_ops(csdev)->enable) {
 			ret = coresight_control_assoc_ectdev(csdev, true);
-- 
2.17.1

[PATCH v6 03/14] coresight: perf: traceid: Add perf ID allocation and notifiers

[Mike Leach]

Adds in calls to allocate and release Trace ID for the CPUs in use
by the perf session.

Adds in notifier calls to the trace ID allocator that perf
events are starting and stopping.

This ensures that Trace IDs associated with CPUs remain the same
throughout the perf session, and are only released when all perf
sessions are complete.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-etm-perf.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index 43bbd5dc3d3b..bdb9ab86173a 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -22,6 +22,7 @@
 #include "coresight-etm-perf.h"
 #include "coresight-priv.h"
 #include "coresight-syscfg.h"
+#include "coresight-trace-id.h"
 
 static struct pmu etm_pmu;
 static bool etm_perf_up;
@@ -228,8 +229,12 @@ static void free_event_data(struct work_struct *work)
 		if (!(IS_ERR_OR_NULL(*ppath)))
 			coresight_release_path(*ppath);
 		*ppath = NULL;
+		coresight_trace_id_put_cpu_id(cpu);
 	}
 
+	/* mark perf event as done for trace id allocator */
+	coresight_trace_id_perf_stop();
+
 	free_percpu(event_data->path);
 	kfree(event_data);
 }
@@ -300,6 +305,7 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
 {
 	u32 id, cfg_hash;
 	int cpu = event->cpu;
+	int trace_id;
 	cpumask_t *mask;
 	struct coresight_device *sink = NULL;
 	struct coresight_device *user_sink = NULL, *last_sink = NULL;
@@ -316,6 +322,9 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
 		sink = user_sink = coresight_get_sink_by_id(id);
 	}
 
+	/* tell the trace ID allocator that a perf event is starting up */
+	coresight_trace_id_perf_start();
+
 	/* check if user wants a coresight configuration selected */
 	cfg_hash = (u32)((event->attr.config2 & GENMASK_ULL(63, 32)) >> 32);
 	if (cfg_hash) {
@@ -388,6 +397,13 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
 			continue;
 		}
 
+		/* ensure we can allocate a trace ID for this CPU */
+		trace_id = coresight_trace_id_get_cpu_id(cpu);
+		if (!IS_VALID_CS_TRACE_ID(trace_id)) {
+			cpumask_clear_cpu(cpu, mask);
+			continue;
+		}
+
 		*etm_event_cpu_path_ptr(event_data, cpu) = path;
 	}
 
-- 
2.17.1

[PATCH v6 04/14] coresight: stm: Update STM driver to use Trace ID API

[Mike Leach]

Updates the STM driver to use the trace ID allocation API.
This uses the _system_id calls to allocate an ID on device poll,
and release on device remove.

The sysfs access to the STMTRACEIDR register has been changed from RW
to RO. Having this value as writable is not appropriate for the new
Trace ID scheme - and had potential to cause errors in the previous
scheme if values clashed with other sources.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-stm.c | 41 +++++++--------------
 1 file changed, 14 insertions(+), 27 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
index 463f449cfb79..6af1b996af6f 100644
--- a/drivers/hwtracing/coresight/coresight-stm.c
+++ b/drivers/hwtracing/coresight/coresight-stm.c
@@ -31,6 +31,7 @@
 #include <linux/stm.h>
 
 #include "coresight-priv.h"
+#include "coresight-trace-id.h"
 
 #define STMDMASTARTR			0xc04
 #define STMDMASTOPR			0xc08
@@ -615,24 +616,7 @@ static ssize_t traceid_show(struct device *dev,
 	val = drvdata->traceid;
 	return sprintf(buf, "%#lx\n", val);
 }
-
-static ssize_t traceid_store(struct device *dev,
-			     struct device_attribute *attr,
-			     const char *buf, size_t size)
-{
-	int ret;
-	unsigned long val;
-	struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);
-
-	ret = kstrtoul(buf, 16, &val);
-	if (ret)
-		return ret;
-
-	/* traceid field is 7bit wide on STM32 */
-	drvdata->traceid = val & 0x7f;
-	return size;
-}
-static DEVICE_ATTR_RW(traceid);
+static DEVICE_ATTR_RO(traceid);
 
 static struct attribute *coresight_stm_attrs[] = {
 	&dev_attr_hwevent_enable.attr,
@@ -803,14 +787,6 @@ static void stm_init_default_data(struct stm_drvdata *drvdata)
 	 */
 	drvdata->stmsper = ~0x0;
 
-	/*
-	 * The trace ID value for *ETM* tracers start at CPU_ID * 2 + 0x10 and
-	 * anything equal to or higher than 0x70 is reserved.  Since 0x00 is
-	 * also reserved the STM trace ID needs to be higher than 0x00 and
-	 * lowner than 0x10.
-	 */
-	drvdata->traceid = 0x1;
-
 	/* Set invariant transaction timing on all channels */
 	bitmap_clear(drvdata->chs.guaranteed, 0, drvdata->numsp);
 }
@@ -838,7 +814,7 @@ static void stm_init_generic_data(struct stm_drvdata *drvdata,
 
 static int stm_probe(struct amba_device *adev, const struct amba_id *id)
 {
-	int ret;
+	int ret, trace_id;
 	void __iomem *base;
 	struct device *dev = &adev->dev;
 	struct coresight_platform_data *pdata = NULL;
@@ -922,12 +898,22 @@ static int stm_probe(struct amba_device *adev, const struct amba_id *id)
 		goto stm_unregister;
 	}
 
+	trace_id = coresight_trace_id_get_system_id();
+	if (trace_id < 0) {
+		ret = trace_id;
+		goto cs_unregister;
+	}
+	drvdata->traceid = (u8)trace_id;
+
 	pm_runtime_put(&adev->dev);
 
 	dev_info(&drvdata->csdev->dev, "%s initialized\n",
 		 (char *)coresight_get_uci_data(id));
 	return 0;
 
+cs_unregister:
+	coresight_unregister(drvdata->csdev);
+
 stm_unregister:
 	stm_unregister_device(&drvdata->stm);
 	return ret;
@@ -937,6 +923,7 @@ static void stm_remove(struct amba_device *adev)
 {
 	struct stm_drvdata *drvdata = dev_get_drvdata(&adev->dev);
 
+	coresight_trace_id_put_system_id(drvdata->traceid);
 	coresight_unregister(drvdata->csdev);
 
 	stm_unregister_device(&drvdata->stm);
-- 
2.17.1

[PATCH v6 05/14] coresight: etm4x: Update ETM4 driver to use Trace ID API

[Mike Leach]

The trace ID API is now used to allocate trace IDs for ETM4.x / ETE
devices.

For perf sessions, these will be allocated on enable, and released on
disable.

For sysfs sessions, these will be allocated on enable, but only released
on reset. This allows the sysfs session to interrogate the Trace ID used
after the session is over - maintaining functional consistency with the
previous allocation scheme.

The trace ID will also be allocated on read of the mgmt/trctraceid file.
This ensures that if perf or sysfs read this before enabling trace, the
value will be the one used for the trace session.

Trace ID initialisation is removed from the _probe() function.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 .../coresight/coresight-etm4x-core.c          | 73 +++++++++++++++++--
 .../coresight/coresight-etm4x-sysfs.c         | 27 ++++++-
 drivers/hwtracing/coresight/coresight-etm4x.h |  3 +
 3 files changed, 93 insertions(+), 10 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 9dc0d7f57565..0656577d7e30 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -42,6 +42,7 @@
 #include "coresight-etm4x-cfg.h"
 #include "coresight-self-hosted-trace.h"
 #include "coresight-syscfg.h"
+#include "coresight-trace-id.h"
 
 static int boot_enable;
 module_param(boot_enable, int, 0444);
@@ -237,6 +238,30 @@ static int etm4_trace_id(struct coresight_device *csdev)
 	return drvdata->trcid;
 }
 
+int etm4_read_alloc_trace_id(struct etmv4_drvdata *drvdata)
+{
+	int trace_id;
+
+	/*
+	 * This will allocate a trace ID to the cpu,
+	 * or return the one currently allocated.
+	 * The trace id function has its own lock
+	 */
+	trace_id = coresight_trace_id_get_cpu_id(drvdata->cpu);
+	if (IS_VALID_CS_TRACE_ID(trace_id))
+		drvdata->trcid = (u8)trace_id;
+	else
+		dev_err(&drvdata->csdev->dev,
+			"Failed to allocate trace ID for %s on CPU%d\n",
+			dev_name(&drvdata->csdev->dev), drvdata->cpu);
+	return trace_id;
+}
+
+void etm4_release_trace_id(struct etmv4_drvdata *drvdata)
+{
+	coresight_trace_id_put_cpu_id(drvdata->cpu);
+}
+
 struct etm4_enable_arg {
 	struct etmv4_drvdata *drvdata;
 	int rc;
@@ -720,7 +745,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
 static int etm4_enable_perf(struct coresight_device *csdev,
 			    struct perf_event *event)
 {
-	int ret = 0;
+	int ret = 0, trace_id;
 	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
 
 	if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id())) {
@@ -732,6 +757,24 @@ static int etm4_enable_perf(struct coresight_device *csdev,
 	ret = etm4_parse_event_config(csdev, event);
 	if (ret)
 		goto out;
+
+	/*
+	 * perf allocates cpu ids as part of _setup_aux() - device needs to use
+	 * the allocated ID. This reads the current version without allocation.
+	 *
+	 * This does not use the trace id lock to prevent lock_dep issues
+	 * with perf locks - we know the ID cannot change until perf shuts down
+	 * the session
+	 */
+	trace_id = coresight_trace_id_read_cpu_id(drvdata->cpu);
+	if (!IS_VALID_CS_TRACE_ID(trace_id)) {
+		dev_err(&drvdata->csdev->dev, "Failed to set trace ID for %s on CPU%d\n",
+			dev_name(&drvdata->csdev->dev), drvdata->cpu);
+		ret = -EINVAL;
+		goto out;
+	}
+	drvdata->trcid = (u8)trace_id;
+
 	/* And enable it */
 	ret = etm4_enable_hw(drvdata);
 
@@ -756,6 +799,11 @@ static int etm4_enable_sysfs(struct coresight_device *csdev)
 
 	spin_lock(&drvdata->spinlock);
 
+	/* sysfs needs to read and allocate a trace ID */
+	ret = etm4_read_alloc_trace_id(drvdata);
+	if (ret < 0)
+		goto unlock_sysfs_enable;
+
 	/*
 	 * Executing etm4_enable_hw on the cpu whose ETM is being enabled
 	 * ensures that register writes occur when cpu is powered.
@@ -767,6 +815,11 @@ static int etm4_enable_sysfs(struct coresight_device *csdev)
 		ret = arg.rc;
 	if (!ret)
 		drvdata->sticky_enable = true;
+
+	if (ret)
+		etm4_release_trace_id(drvdata);
+
+unlock_sysfs_enable:
 	spin_unlock(&drvdata->spinlock);
 
 	if (!ret)
@@ -898,6 +951,11 @@ static int etm4_disable_perf(struct coresight_device *csdev,
 	/* TRCVICTLR::SSSTATUS, bit[9] */
 	filters->ssstatus = (control & BIT(9));
 
+	/*
+	 * perf will release trace ids when _free_aux() is
+	 * called at the end of the session.
+	 */
+
 	return 0;
 }
 
@@ -923,6 +981,13 @@ static void etm4_disable_sysfs(struct coresight_device *csdev)
 	spin_unlock(&drvdata->spinlock);
 	cpus_read_unlock();
 
+	/*
+	 * we only release trace IDs when resetting sysfs.
+	 * This permits sysfs users to read the trace ID after the trace
+	 * session has completed. This maintains operational behaviour with
+	 * prior trace id allocation method
+	 */
+
 	dev_dbg(&csdev->dev, "ETM tracing disabled\n");
 }
 
@@ -1565,11 +1630,6 @@ static int etm4_dying_cpu(unsigned int cpu)
 	return 0;
 }
 
-static void etm4_init_trace_id(struct etmv4_drvdata *drvdata)
-{
-	drvdata->trcid = coresight_get_trace_id(drvdata->cpu);
-}
-
 static int __etm4_cpu_save(struct etmv4_drvdata *drvdata)
 {
 	int i, ret = 0;
@@ -1946,7 +2006,6 @@ static int etm4_add_coresight_dev(struct etm4_init_arg *init_arg)
 	if (!desc.name)
 		return -ENOMEM;
 
-	etm4_init_trace_id(drvdata);
 	etm4_set_default(&drvdata->config);
 
 	pdata = coresight_get_platform_data(dev);
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
index 9cac848cffaf..5e62aa40ecd0 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c
@@ -266,10 +266,11 @@ static ssize_t reset_store(struct device *dev,
 	config->vmid_mask0 = 0x0;
 	config->vmid_mask1 = 0x0;
 
-	drvdata->trcid = drvdata->cpu + 1;
-
 	spin_unlock(&drvdata->spinlock);
 
+	/* for sysfs - only release trace id when resetting */
+	etm4_release_trace_id(drvdata);
+
 	cscfg_csdev_reset_feats(to_coresight_device(dev));
 
 	return size;
@@ -2392,6 +2393,26 @@ static struct attribute *coresight_etmv4_attrs[] = {
 	NULL,
 };
 
+/*
+ * Trace ID allocated dynamically on enable - but also allocate on read
+ * in case sysfs or perf read before enable to ensure consistent metadata
+ * information for trace decode
+ */
+static ssize_t trctraceid_show(struct device *dev,
+			       struct device_attribute *attr,
+			       char *buf)
+{
+	int trace_id;
+	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+
+	trace_id = etm4_read_alloc_trace_id(drvdata);
+	if (trace_id < 0)
+		return trace_id;
+
+	return sysfs_emit(buf, "0x%x\n", trace_id);
+}
+static DEVICE_ATTR_RO(trctraceid);
+
 struct etmv4_reg {
 	struct coresight_device *csdev;
 	u32 offset;
@@ -2528,7 +2549,7 @@ static struct attribute *coresight_etmv4_mgmt_attrs[] = {
 	coresight_etm4x_reg(trcpidr3, TRCPIDR3),
 	coresight_etm4x_reg(trcoslsr, TRCOSLSR),
 	coresight_etm4x_reg(trcconfig, TRCCONFIGR),
-	coresight_etm4x_reg(trctraceid, TRCTRACEIDR),
+	&dev_attr_trctraceid.attr,
 	coresight_etm4x_reg(trcdevarch, TRCDEVARCH),
 	NULL,
 };
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
index 4b21bb79f168..434f4e95ee17 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.h
+++ b/drivers/hwtracing/coresight/coresight-etm4x.h
@@ -1095,4 +1095,7 @@ static inline bool etm4x_is_ete(struct etmv4_drvdata *drvdata)
 {
 	return drvdata->arch >= ETM_ARCH_ETE;
 }
+
+int etm4_read_alloc_trace_id(struct etmv4_drvdata *drvdata);
+void etm4_release_trace_id(struct etmv4_drvdata *drvdata);
 #endif
-- 
2.17.1

[PATCH v6 06/14] coresight: etm3x: Update ETM3 driver to use Trace ID API

[Mike Leach]

Use the TraceID API to allocate ETM trace IDs dynamically.

As with the etm4x we allocate on enable / disable for perf,
allocate on enable / reset for sysfs.

Additionally we allocate on sysfs file read as both perf and sysfs
can read the ID before enabling the hardware.

Remove sysfs option to write trace ID - which is inconsistent with
both the dynamic allocation method and the fixed allocation method
previously used.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-etm.h   |  2 +
 .../coresight/coresight-etm3x-core.c          | 72 +++++++++++++++++--
 .../coresight/coresight-etm3x-sysfs.c         | 27 ++-----
 3 files changed, 75 insertions(+), 26 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm.h b/drivers/hwtracing/coresight/coresight-etm.h
index f3ab96eaf44e..3667428d38b6 100644
--- a/drivers/hwtracing/coresight/coresight-etm.h
+++ b/drivers/hwtracing/coresight/coresight-etm.h
@@ -287,4 +287,6 @@ int etm_get_trace_id(struct etm_drvdata *drvdata);
 void etm_set_default(struct etm_config *config);
 void etm_config_trace_mode(struct etm_config *config);
 struct etm_config *get_etm_config(struct etm_drvdata *drvdata);
+int etm_read_alloc_trace_id(struct etm_drvdata *drvdata);
+void etm_release_trace_id(struct etm_drvdata *drvdata);
 #endif
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
index d0ab9933472b..090b6fbf6305 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
@@ -32,6 +32,7 @@
 
 #include "coresight-etm.h"
 #include "coresight-etm-perf.h"
+#include "coresight-trace-id.h"
 
 /*
  * Not really modular but using module_param is the easiest way to
@@ -490,16 +491,59 @@ static int etm_trace_id(struct coresight_device *csdev)
 	return etm_get_trace_id(drvdata);
 }
 
+int etm_read_alloc_trace_id(struct etm_drvdata *drvdata)
+{
+	int trace_id;
+
+	/*
+	 * This will allocate a trace ID to the cpu,
+	 * or return the one currently allocated.
+	 *
+	 * trace id function has its own lock
+	 */
+	trace_id = coresight_trace_id_get_cpu_id(drvdata->cpu);
+	if (IS_VALID_CS_TRACE_ID(trace_id))
+		drvdata->traceid = (u8)trace_id;
+	else
+		dev_err(&drvdata->csdev->dev,
+			"Failed to allocate trace ID for %s on CPU%d\n",
+			dev_name(&drvdata->csdev->dev), drvdata->cpu);
+	return trace_id;
+}
+
+void etm_release_trace_id(struct etm_drvdata *drvdata)
+{
+	coresight_trace_id_put_cpu_id(drvdata->cpu);
+}
+
 static int etm_enable_perf(struct coresight_device *csdev,
 			   struct perf_event *event)
 {
 	struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+	int trace_id;
 
 	if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id()))
 		return -EINVAL;
 
 	/* Configure the tracer based on the session's specifics */
 	etm_parse_event_config(drvdata, event);
+
+	/*
+	 * perf allocates cpu ids as part of _setup_aux() - device needs to use
+	 * the allocated ID. This reads the current version without allocation.
+	 *
+	 * This does not use the trace id lock to prevent lock_dep issues
+	 * with perf locks - we know the ID cannot change until perf shuts down
+	 * the session
+	 */
+	trace_id = coresight_trace_id_read_cpu_id(drvdata->cpu);
+	if (!IS_VALID_CS_TRACE_ID(trace_id)) {
+		dev_err(&drvdata->csdev->dev, "Failed to set trace ID for %s on CPU%d\n",
+			dev_name(&drvdata->csdev->dev), drvdata->cpu);
+		return -EINVAL;
+	}
+	drvdata->traceid = (u8)trace_id;
+
 	/* And enable it */
 	return etm_enable_hw(drvdata);
 }
@@ -512,6 +556,11 @@ static int etm_enable_sysfs(struct coresight_device *csdev)
 
 	spin_lock(&drvdata->spinlock);
 
+	/* sysfs needs to allocate and set a trace ID */
+	ret = etm_read_alloc_trace_id(drvdata);
+	if (ret < 0)
+		goto unlock_enable_sysfs;
+
 	/*
 	 * Configure the ETM only if the CPU is online.  If it isn't online
 	 * hw configuration will take place on the local CPU during bring up.
@@ -528,6 +577,10 @@ static int etm_enable_sysfs(struct coresight_device *csdev)
 		ret = -ENODEV;
 	}
 
+	if (ret)
+		etm_release_trace_id(drvdata);
+
+unlock_enable_sysfs:
 	spin_unlock(&drvdata->spinlock);
 
 	if (!ret)
@@ -611,6 +664,12 @@ static void etm_disable_perf(struct coresight_device *csdev)
 	coresight_disclaim_device_unlocked(csdev);
 
 	CS_LOCK(drvdata->base);
+
+	/*
+	 * perf will release trace ids when _free_aux()
+	 * is called at the end of the session
+	 */
+
 }
 
 static void etm_disable_sysfs(struct coresight_device *csdev)
@@ -635,6 +694,13 @@ static void etm_disable_sysfs(struct coresight_device *csdev)
 	spin_unlock(&drvdata->spinlock);
 	cpus_read_unlock();
 
+	/*
+	 * we only release trace IDs when resetting sysfs.
+	 * This permits sysfs users to read the trace ID after the trace
+	 * session has completed. This maintains operational behaviour with
+	 * prior trace id allocation method
+	 */
+
 	dev_dbg(&csdev->dev, "ETM tracing disabled\n");
 }
 
@@ -781,11 +847,6 @@ static void etm_init_arch_data(void *info)
 	CS_LOCK(drvdata->base);
 }
 
-static void etm_init_trace_id(struct etm_drvdata *drvdata)
-{
-	drvdata->traceid = coresight_get_trace_id(drvdata->cpu);
-}
-
 static int __init etm_hp_setup(void)
 {
 	int ret;
@@ -871,7 +932,6 @@ static int etm_probe(struct amba_device *adev, const struct amba_id *id)
 	if (etm_arch_supported(drvdata->arch) == false)
 		return -EINVAL;
 
-	etm_init_trace_id(drvdata);
 	etm_set_default(&drvdata->config);
 
 	pdata = coresight_get_platform_data(dev);
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
index fd81eca3ec18..2f271b7fb048 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
@@ -85,6 +85,7 @@ static ssize_t reset_store(struct device *dev,
 		}
 
 		etm_set_default(config);
+		etm_release_trace_id(drvdata);
 		spin_unlock(&drvdata->spinlock);
 	}
 
@@ -1189,30 +1190,16 @@ static DEVICE_ATTR_RO(cpu);
 static ssize_t traceid_show(struct device *dev,
 			    struct device_attribute *attr, char *buf)
 {
-	unsigned long val;
-	struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
-
-	val = etm_get_trace_id(drvdata);
-
-	return sprintf(buf, "%#lx\n", val);
-}
-
-static ssize_t traceid_store(struct device *dev,
-			     struct device_attribute *attr,
-			     const char *buf, size_t size)
-{
-	int ret;
-	unsigned long val;
+	int trace_id;
 	struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
 
-	ret = kstrtoul(buf, 16, &val);
-	if (ret)
-		return ret;
+	trace_id = etm_read_alloc_trace_id(drvdata);
+	if (trace_id < 0)
+		return trace_id;
 
-	drvdata->traceid = val & ETM_TRACEID_MASK;
-	return size;
+	return sysfs_emit(buf, "%#x\n", trace_id);
 }
-static DEVICE_ATTR_RW(traceid);
+static DEVICE_ATTR_RO(traceid);
 
 static struct attribute *coresight_etm_attrs[] = {
 	&dev_attr_nr_addr_cmp.attr,
-- 
2.17.1

[PATCH v6 07/14] coresight: etmX.X: stm: Remove trace_id() callback

[Mike Leach]

CoreSight sources provide a callback (.trace_id) in the standard source
ops which returns the ID to the core code. This was used to check that
sources all had a unique Trace ID.

Uniqueness is now gauranteed by the Trace ID allocation system, and the
check code has been removed from the core.

This patch removes the unneeded and unused .trace_id source ops
from the ops structure and implementations in etm3x, etm4x and stm.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-etm.h   |  1 -
 .../coresight/coresight-etm3x-core.c          | 37 -------------------
 .../coresight/coresight-etm4x-core.c          |  8 ----
 drivers/hwtracing/coresight/coresight-stm.c   |  8 ----
 include/linux/coresight.h                     |  3 --
 5 files changed, 57 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm.h b/drivers/hwtracing/coresight/coresight-etm.h
index 3667428d38b6..9a0d08b092ae 100644
--- a/drivers/hwtracing/coresight/coresight-etm.h
+++ b/drivers/hwtracing/coresight/coresight-etm.h
@@ -283,7 +283,6 @@ static inline unsigned int etm_readl(struct etm_drvdata *drvdata, u32 off)
 }
 
 extern const struct attribute_group *coresight_etm_groups[];
-int etm_get_trace_id(struct etm_drvdata *drvdata);
 void etm_set_default(struct etm_config *config);
 void etm_config_trace_mode(struct etm_config *config);
 struct etm_config *get_etm_config(struct etm_drvdata *drvdata);
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
index 090b6fbf6305..afc57195ee52 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
@@ -455,42 +455,6 @@ static int etm_cpu_id(struct coresight_device *csdev)
 	return drvdata->cpu;
 }
 
-int etm_get_trace_id(struct etm_drvdata *drvdata)
-{
-	unsigned long flags;
-	int trace_id = -1;
-	struct device *etm_dev;
-
-	if (!drvdata)
-		goto out;
-
-	etm_dev = drvdata->csdev->dev.parent;
-	if (!local_read(&drvdata->mode))
-		return drvdata->traceid;
-
-	pm_runtime_get_sync(etm_dev);
-
-	spin_lock_irqsave(&drvdata->spinlock, flags);
-
-	CS_UNLOCK(drvdata->base);
-	trace_id = (etm_readl(drvdata, ETMTRACEIDR) & ETM_TRACEID_MASK);
-	CS_LOCK(drvdata->base);
-
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
-	pm_runtime_put(etm_dev);
-
-out:
-	return trace_id;
-
-}
-
-static int etm_trace_id(struct coresight_device *csdev)
-{
-	struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
-
-	return etm_get_trace_id(drvdata);
-}
-
 int etm_read_alloc_trace_id(struct etm_drvdata *drvdata)
 {
 	int trace_id;
@@ -737,7 +701,6 @@ static void etm_disable(struct coresight_device *csdev,
 
 static const struct coresight_ops_source etm_source_ops = {
 	.cpu_id		= etm_cpu_id,
-	.trace_id	= etm_trace_id,
 	.enable		= etm_enable,
 	.disable	= etm_disable,
 };
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 0656577d7e30..bc576e254b8f 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -231,13 +231,6 @@ static int etm4_cpu_id(struct coresight_device *csdev)
 	return drvdata->cpu;
 }
 
-static int etm4_trace_id(struct coresight_device *csdev)
-{
-	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
-
-	return drvdata->trcid;
-}
-
 int etm4_read_alloc_trace_id(struct etmv4_drvdata *drvdata)
 {
 	int trace_id;
@@ -1021,7 +1014,6 @@ static void etm4_disable(struct coresight_device *csdev,
 
 static const struct coresight_ops_source etm4_source_ops = {
 	.cpu_id		= etm4_cpu_id,
-	.trace_id	= etm4_trace_id,
 	.enable		= etm4_enable,
 	.disable	= etm4_disable,
 };
diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
index 6af1b996af6f..66a614c5492c 100644
--- a/drivers/hwtracing/coresight/coresight-stm.c
+++ b/drivers/hwtracing/coresight/coresight-stm.c
@@ -281,15 +281,7 @@ static void stm_disable(struct coresight_device *csdev,
 	}
 }
 
-static int stm_trace_id(struct coresight_device *csdev)
-{
-	struct stm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
-
-	return drvdata->traceid;
-}
-
 static const struct coresight_ops_source stm_source_ops = {
-	.trace_id	= stm_trace_id,
 	.enable		= stm_enable,
 	.disable	= stm_disable,
 };
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index 1554021231f9..e241eb88dfb9 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -314,14 +314,11 @@ struct coresight_ops_link {
  * Operations available for sources.
  * @cpu_id:	returns the value of the CPU number this component
  *		is associated to.
- * @trace_id:	returns the value of the component's trace ID as known
- *		to the HW.
  * @enable:	enables tracing for a source.
  * @disable:	disables tracing for a source.
  */
 struct coresight_ops_source {
 	int (*cpu_id)(struct coresight_device *csdev);
-	int (*trace_id)(struct coresight_device *csdev);
 	int (*enable)(struct coresight_device *csdev,
 		      struct perf_event *event,  u32 mode);
 	void (*disable)(struct coresight_device *csdev,
-- 
2.17.1

[PATCH v6 08/14] coresight: trace id: Remove legacy get trace ID function.

[Mike Leach]

Removes legacy coresight_get_trace_id() function now its use has been
removed from the ETM code.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 include/linux/coresight-pmu.h | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/include/linux/coresight-pmu.h b/include/linux/coresight-pmu.h
index ffff4e6277e5..624f4843453e 100644
--- a/include/linux/coresight-pmu.h
+++ b/include/linux/coresight-pmu.h
@@ -8,7 +8,6 @@
 #define _LINUX_CORESIGHT_PMU_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
@@ -44,15 +43,4 @@
 #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
-- 
2.17.1

[PATCH v6 09/14] 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.c            | 92 +++++++++++++++++++----------
 tools/perf/util/cs-etm.h            | 14 ++++-
 3 files changed, 77 insertions(+), 34 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.c b/tools/perf/util/cs-etm.c
index 16db965ac995..11026c9694a4 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -193,6 +193,30 @@ 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)
 {
@@ -2881,18 +2905,47 @@ static int cs_etm__queue_aux_records(struct perf_session *session)
 	return 0;
 }
 
+/* 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(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;
 	unsigned int pmu_type;
 	int event_header_size = sizeof(struct perf_event_header);
 	int info_header_size;
 	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, *hdr = NULL;
@@ -2962,23 +3015,13 @@ int cs_etm__process_auxtrace_info(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]);
@@ -2990,26 +3033,6 @@ int cs_etm__process_auxtrace_info(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];
 	}
 
 	/*
@@ -3090,6 +3113,11 @@ int cs_etm__process_auxtrace_info(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 90c83f932d9a..712a6f855f0e 100644
--- a/tools/perf/util/cs-etm.h
+++ b/tools/perf/util/cs-etm.h
@@ -28,13 +28,17 @@ 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 unused ID.
  */
-#define CS_HEADER_CURRENT_VERSION 1
+#define CS_HEADER_CURRENT_VERSION	2
+#define CS_AUX_HW_ID_VERSION_MIN	2
 
 /* Beginning of header common to both ETMv3 and V4 */
 enum {
@@ -85,6 +89,12 @@ 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 v6 10/14] 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 | 30 +++++++++++++++++------------
 tools/perf/arch/arm/util/cs-etm.c   | 21 ++++++++++++--------
 2 files changed, 31 insertions(+), 20 deletions(-)

diff --git a/tools/include/linux/coresight-pmu.h b/tools/include/linux/coresight-pmu.h
index db9c7c0abb6a..307f357defe9 100644
--- a/tools/include/linux/coresight-pmu.h
+++ b/tools/include/linux/coresight-pmu.h
@@ -10,11 +10,28 @@
 #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 e.g. simpleperf in Android, 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 +56,4 @@
 #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 a346d5f3dafa..c7e4b543259f 100644
--- a/tools/perf/arch/arm/util/cs-etm.c
+++ b/tools/perf/arch/arm/util/cs-etm.c
@@ -421,13 +421,16 @@ 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)
@@ -633,8 +636,10 @@ 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]);
@@ -681,9 +686,9 @@ 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 v6 11/14] kernel: events: Export perf_report_aux_output_id()

[Mike Leach]

CoreSight trace being updated to use the perf_report_aux_output_id()
in a similar way to intel-pt.

This function in needs export visibility to allow it to be called from
kernel loadable modules, which CoreSight may configured to be built as.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 kernel/events/core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 4ec3717003d5..ad388552f1d5 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9231,6 +9231,7 @@ void perf_report_aux_output_id(struct perf_event *event, u64 hw_id)
 
 	perf_output_end(&handle);
 }
+EXPORT_SYMBOL_GPL(perf_report_aux_output_id);
 
 static int
 __perf_event_account_interrupt(struct perf_event *event, int throttle)
-- 
2.17.1

[PATCH v6 12/14] 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                      | 248 ++++++++++++++++--
 3 files changed, 251 insertions(+), 19 deletions(-)

diff --git a/tools/include/linux/coresight-pmu.h b/tools/include/linux/coresight-pmu.h
index 307f357defe9..57ba1abf1224 100644
--- a/tools/include/linux/coresight-pmu.h
+++ b/tools/include/linux/coresight-pmu.h
@@ -32,6 +32,9 @@
  */
 #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.
@@ -56,4 +59,16 @@
 #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 31fa3b45134a..fa3aa9c0fb2e 100644
--- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
+++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
@@ -625,6 +625,7 @@ 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 :
@@ -632,11 +633,13 @@ 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;
@@ -645,6 +648,10 @@ 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 11026c9694a4..f9f7d16a55d1 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -217,6 +217,143 @@ 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)
 {
@@ -2662,7 +2799,7 @@ 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)
+		else if (version == 1 || version == 2)
 			err = cs_etm__print_cpu_metadata_v1(val, &i);
 		if (err)
 			return;
@@ -2774,11 +2911,16 @@ 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) {
@@ -2827,6 +2969,17 @@ 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)
 {
@@ -2916,13 +3069,13 @@ 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 */
@@ -2935,6 +3088,35 @@ 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(union perf_event *event,
 				  struct perf_session *session)
 {
@@ -2947,6 +3129,7 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
 	int priv_size = 0;
 	int num_cpu;
 	int err = 0;
+	int aux_hw_id_found;
 	int i, j;
 	u64 *ptr, *hdr = NULL;
 	u64 **metadata = NULL;
@@ -3113,8 +3296,43 @@ int cs_etm__process_auxtrace_info(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;
 
@@ -3123,14 +3341,6 @@ int cs_etm__process_auxtrace_info(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

[PATCH v6 13/14] coresight: events: PERF_RECORD_AUX_OUTPUT_HW_ID used for Trace ID

[Mike Leach]

Use the perf_report_aux_output_id() call to output the CoreSight trace ID
and associated CPU as a PERF_RECORD_AUX_OUTPUT_HW_ID record in the
perf.data file.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-etm-perf.c |  7 +++++++
 include/linux/coresight-pmu.h                    | 14 ++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index bdb9ab86173a..12fff661456e 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -4,6 +4,7 @@
  * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
  */
 
+#include <linux/bitfield.h>
 #include <linux/coresight.h>
 #include <linux/coresight-pmu.h>
 #include <linux/cpumask.h>
@@ -448,6 +449,7 @@ static void etm_event_start(struct perf_event *event, int flags)
 	struct perf_output_handle *handle = &ctxt->handle;
 	struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
 	struct list_head *path;
+	u64 hw_id;
 
 	if (!csdev)
 		goto fail;
@@ -493,6 +495,11 @@ static void etm_event_start(struct perf_event *event, int flags)
 	if (source_ops(csdev)->enable(csdev, event, CS_MODE_PERF))
 		goto fail_disable_path;
 
+	/* output cpu / trace ID in perf record */
+	hw_id = FIELD_PREP(CS_AUX_HW_ID_VERSION_MASK, CS_AUX_HW_ID_CURR_VERSION);
+	hw_id |= FIELD_PREP(CS_AUX_HW_ID_TRACE_ID_MASK, coresight_trace_id_read_cpu_id(cpu));
+	perf_report_aux_output_id(event, hw_id);
+
 out:
 	/* Tell the perf core the event is alive */
 	event->hw.state = 0;
diff --git a/include/linux/coresight-pmu.h b/include/linux/coresight-pmu.h
index 624f4843453e..51ac441a37c3 100644
--- a/include/linux/coresight-pmu.h
+++ b/include/linux/coresight-pmu.h
@@ -7,6 +7,8 @@
 #ifndef _LINUX_CORESIGHT_PMU_H
 #define _LINUX_CORESIGHT_PMU_H
 
+#include <linux/bits.h>
+
 #define CORESIGHT_ETM_PMU_NAME "cs_etm"
 
 /*
@@ -43,4 +45,16 @@
 #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
-- 
2.17.1

[PATCH v6 14/14] coresight: trace-id: Add debug & test macros to Trace ID allocation

[Mike Leach]

Adds in a number of pr_debug macros to allow the debugging and test of
the trace ID allocation system.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
---
 .../hwtracing/coresight/coresight-trace-id.c  | 33 +++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-trace-id.c b/drivers/hwtracing/coresight/coresight-trace-id.c
index 9b85c376cb12..367bbfb4c213 100644
--- a/drivers/hwtracing/coresight/coresight-trace-id.c
+++ b/drivers/hwtracing/coresight/coresight-trace-id.c
@@ -24,6 +24,27 @@ static atomic_t perf_cs_etm_session_active = ATOMIC_INIT(0);
 /* lock to protect id_map and cpu data  */
 static DEFINE_SPINLOCK(id_map_lock);
 
+/* #define TRACE_ID_DEBUG 1 */
+#if defined(TRACE_ID_DEBUG) || defined(CONFIG_COMPILE_TEST)
+
+static void coresight_trace_id_dump_table(struct coresight_trace_id_map *id_map,
+					  const char *func_name)
+{
+	pr_debug("%s id_map::\n", func_name);
+	pr_debug("Used = %*pb\n", CORESIGHT_TRACE_IDS_MAX, id_map->used_ids);
+	pr_debug("Pend = %*pb\n", CORESIGHT_TRACE_IDS_MAX, id_map->pend_rel_ids);
+}
+#define DUMP_ID_MAP(map)   coresight_trace_id_dump_table(map, __func__)
+#define DUMP_ID_CPU(cpu, id) pr_debug("%s called;  cpu=%d, id=%d\n", __func__, cpu, id)
+#define DUMP_ID(id)   pr_debug("%s called; id=%d\n", __func__, id)
+#define PERF_SESSION(n) pr_debug("%s perf count %d\n", __func__, n)
+#else
+#define DUMP_ID_MAP(map)
+#define DUMP_ID(id)
+#define DUMP_ID_CPU(cpu, id)
+#define PERF_SESSION(n)
+#endif
+
 /* unlocked read of current trace ID value for given CPU */
 static int _coresight_trace_id_read_cpu_id(int cpu)
 {
@@ -127,6 +148,7 @@ static void coresight_trace_id_release_all_pending(void)
 		cpumask_clear_cpu(cpu, &cpu_id_release_pending);
 	}
 	spin_unlock_irqrestore(&id_map_lock, flags);
+	DUMP_ID_MAP(id_map);
 }
 
 static int coresight_trace_id_map_get_cpu_id(int cpu, struct coresight_trace_id_map *id_map)
@@ -168,6 +190,8 @@ static int coresight_trace_id_map_get_cpu_id(int cpu, struct coresight_trace_id_
 get_cpu_id_out_unlock:
 	spin_unlock_irqrestore(&id_map_lock, flags);
 
+	DUMP_ID_CPU(cpu, id);
+	DUMP_ID_MAP(id_map);
 	return id;
 }
 
@@ -194,6 +218,8 @@ static void coresight_trace_id_map_put_cpu_id(int cpu, struct coresight_trace_id
 	}
 
 	spin_unlock_irqrestore(&id_map_lock, flags);
+	DUMP_ID_CPU(cpu, id);
+	DUMP_ID_MAP(id_map);
 }
 
 static int coresight_trace_id_map_get_system_id(struct coresight_trace_id_map *id_map)
@@ -206,6 +232,8 @@ static int coresight_trace_id_map_get_system_id(struct coresight_trace_id_map *i
 	id = coresight_trace_id_alloc_new_id(id_map, 0, true);
 	spin_unlock_irqrestore(&id_map_lock, flags);
 
+	DUMP_ID(id);
+	DUMP_ID_MAP(id_map);
 	return id;
 }
 
@@ -216,6 +244,9 @@ static void coresight_trace_id_map_put_system_id(struct coresight_trace_id_map *
 	spin_lock_irqsave(&id_map_lock, flags);
 	coresight_trace_id_free(id, id_map);
 	spin_unlock_irqrestore(&id_map_lock, flags);
+
+	DUMP_ID(id);
+	DUMP_ID_MAP(id_map);
 }
 
 /* API functions */
@@ -253,6 +284,7 @@ EXPORT_SYMBOL_GPL(coresight_trace_id_put_system_id);
 void coresight_trace_id_perf_start(void)
 {
 	atomic_inc(&perf_cs_etm_session_active);
+	PERF_SESSION(atomic_read(&perf_cs_etm_session_active));
 }
 EXPORT_SYMBOL_GPL(coresight_trace_id_perf_start);
 
@@ -260,6 +292,7 @@ void coresight_trace_id_perf_stop(void)
 {
 	if (!atomic_dec_return(&perf_cs_etm_session_active))
 		coresight_trace_id_release_all_pending();
+	PERF_SESSION(atomic_read(&perf_cs_etm_session_active));
 }
 EXPORT_SYMBOL_GPL(coresight_trace_id_perf_stop);
 
-- 
2.17.1

Re: [PATCH v6 11/14] kernel: events: Export perf_report_aux_output_id()

[Suzuki Kuruppassery Poulose]

Peter


On 23/11/2022 19:50, Mike Leach wrote:
> CoreSight trace being updated to use the perf_report_aux_output_id()
> in a similar way to intel-pt.
> 
> This function in needs export visibility to allow it to be called from
> kernel loadable modules, which CoreSight may configured to be built as.
> 
> Signed-off-by: Mike Leach <mike.leach@linaro.org>
> Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> ---
>   kernel/events/core.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 4ec3717003d5..ad388552f1d5 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -9231,6 +9231,7 @@ void perf_report_aux_output_id(struct perf_event *event, u64 hw_id)
>   
>   	perf_output_end(&handle);
>   }
> +EXPORT_SYMBOL_GPL(perf_report_aux_output_id);
>   

Are you happy with me picking up this change through the coresight  tree ?

Suzuki

>   static int
>   __perf_event_account_interrupt(struct perf_event *event, int throttle)

Re: [PATCH v6 11/14] kernel: events: Export perf_report_aux_output_id()

[Suzuki K Poulose]

Peter,

On 24/11/2022 11:04, Suzuki Kuruppassery Poulose wrote:
> Peter
> 
> 
> On 23/11/2022 19:50, Mike Leach wrote:
>> CoreSight trace being updated to use the perf_report_aux_output_id()
>> in a similar way to intel-pt.
>>
>> This function in needs export visibility to allow it to be called from
>> kernel loadable modules, which CoreSight may configured to be built as.
>>
>> Signed-off-by: Mike Leach <mike.leach@linaro.org>
>> Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>> ---
>>   kernel/events/core.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/kernel/events/core.c b/kernel/events/core.c
>> index 4ec3717003d5..ad388552f1d5 100644
>> --- a/kernel/events/core.c
>> +++ b/kernel/events/core.c
>> @@ -9231,6 +9231,7 @@ void perf_report_aux_output_id(struct perf_event 
>> *event, u64 hw_id)
>>       perf_output_end(&handle);
>>   }
>> +EXPORT_SYMBOL_GPL(perf_report_aux_output_id);
> 
> Are you happy with me picking up this change through the coresight  tree ?
> 
> Suzuki
> 

Please could you let me know your thoughts on this ? Coresight PMU would
use this to inform the dynamically allocated trace id for a CPU to the
perf via this HWID packet.

If you are happy with the above change, I could pick it up via the
coresight tree with your Ack. Otherwise, please could you pick it
up ?

Suzuki

Re: [PATCH v6 11/14] kernel: events: Export perf_report_aux_output_id()

[Suzuki K Poulose]

Peter, Ingo, Arnaldo

On 13/12/2022 10:08, Suzuki K Poulose wrote:
> Peter,
> 
> On 24/11/2022 11:04, Suzuki Kuruppassery Poulose wrote:
>> Peter
>>
>>
>> On 23/11/2022 19:50, Mike Leach wrote:
>>> CoreSight trace being updated to use the perf_report_aux_output_id()
>>> in a similar way to intel-pt.
>>>
>>> This function in needs export visibility to allow it to be called from
>>> kernel loadable modules, which CoreSight may configured to be built as.
>>>
>>> Signed-off-by: Mike Leach <mike.leach@linaro.org>
>>> Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>>> ---
>>>   kernel/events/core.c | 1 +
>>>   1 file changed, 1 insertion(+)
>>>
>>> diff --git a/kernel/events/core.c b/kernel/events/core.c
>>> index 4ec3717003d5..ad388552f1d5 100644
>>> --- a/kernel/events/core.c
>>> +++ b/kernel/events/core.c
>>> @@ -9231,6 +9231,7 @@ void perf_report_aux_output_id(struct 
>>> perf_event *event, u64 hw_id)
>>>       perf_output_end(&handle);
>>>   }
>>> +EXPORT_SYMBOL_GPL(perf_report_aux_output_id);
>>
>> Are you happy with me picking up this change through the coresight  
>> tree ?
>>
>> Suzuki
>>
> 
> Please could you let me know your thoughts on this ? Coresight PMU would
> use this to inform the dynamically allocated trace id for a CPU to the
> perf via this HWID packet.
> 
> If you are happy with the above change, I could pick it up via the
> coresight tree with your Ack. Otherwise, please could you pick it
> up ?
>

Please could you let us know if this is acceptable and if so, how can
this be pushed ? CoreSight PMU (which can be built as a module) is using
these packets to advertise the traceID allocated for a given CPU bound
ETM (which is made dynamic due to the limited number of ids available).
The perf tool can use these packets to then decode and separate the
trace data from shared buffer.

As of now, the series to enable the dynamic trace id allocation is
blocked on this change.


Kind regards
Suzuki

> Suzuki
> 

Re: [PATCH v6 11/14] kernel: events: Export perf_report_aux_output_id()

[Peter Zijlstra]

On Wed, Nov 23, 2022 at 07:50:07PM +0000, Mike Leach wrote:
> CoreSight trace being updated to use the perf_report_aux_output_id()
> in a similar way to intel-pt.
> 
> This function in needs export visibility to allow it to be called from
> kernel loadable modules, which CoreSight may configured to be built as.
> 
> Signed-off-by: Mike Leach <mike.leach@linaro.org>
> Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

> ---
>  kernel/events/core.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 4ec3717003d5..ad388552f1d5 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -9231,6 +9231,7 @@ void perf_report_aux_output_id(struct perf_event *event, u64 hw_id)
>  
>  	perf_output_end(&handle);
>  }
> +EXPORT_SYMBOL_GPL(perf_report_aux_output_id);
>  
>  static int
>  __perf_event_account_interrupt(struct perf_event *event, int throttle)
> -- 
> 2.17.1
>