I've taken over this one from German because he's moved to a different team. I gave it a quick check and bumped the version number in the docs for the next release, but the month is an estimate.
Thanks
Changes since v2:
* Rebased onto coresight/next (b99ee26a1a) * Bumped release version to 6.1
Changes since v1:
* Inline etmv4_to_ts_source() function. * Collect review tag from Leo.
German Gomez (2): coresight: etm4x: Expose default timestamp source in sysfs coresight: etm4x: docs: Add documentation for 'ts_source' sysfs interface
.../testing/sysfs-bus-coresight-devices-etm4x | 8 +++++ .../coresight/coresight-etm4x-reference.rst | 14 +++++++++ arch/arm64/include/asm/sysreg.h | 1 + .../coresight/coresight-etm4x-sysfs.c | 29 +++++++++++++++++++ 4 files changed, 52 insertions(+)
From: German Gomez german.gomez@arm.com
Add a new sysfs interface in /sys/bus/coresight/devices/etm<N>/ts_source indicating the configured timestamp source when the ETM device driver was probed.
The perf tool will use this information to detect if the trace data timestamp matches the kernel time, enabling correlation of CoreSight trace with perf events.
Suggested-by: Suzuki K Poulose suzuki.poulose@arm.com Signed-off-by: German Gomez german.gomez@arm.com Reviewed-by: Leo Yan leo.yan@linaro.org Signed-off-by: James Clark james.clark@arm.com --- arch/arm64/include/asm/sysreg.h | 1 + .../coresight/coresight-etm4x-sysfs.c | 29 +++++++++++++++++++ 2 files changed, 30 insertions(+)
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index 7c71358d44c4..7a518a011669 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -1021,6 +1021,7 @@ #define SYS_MPIDR_SAFE_VAL (BIT(31))
#define TRFCR_ELx_TS_SHIFT 5 +#define TRFCR_ELx_TS_MASK ((0x3UL) << TRFCR_ELx_TS_SHIFT) #define TRFCR_ELx_TS_VIRTUAL ((0x1UL) << TRFCR_ELx_TS_SHIFT) #define TRFCR_ELx_TS_GUEST_PHYSICAL ((0x2UL) << TRFCR_ELx_TS_SHIFT) #define TRFCR_ELx_TS_PHYSICAL ((0x3UL) << TRFCR_ELx_TS_SHIFT) diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c index 6ea8181816fc..9cac848cffaf 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c @@ -2306,6 +2306,34 @@ static ssize_t cpu_show(struct device *dev, } static DEVICE_ATTR_RO(cpu);
+static ssize_t ts_source_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + int val; + struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent); + + if (!drvdata->trfcr) { + val = -1; + goto out; + } + + switch (drvdata->trfcr & TRFCR_ELx_TS_MASK) { + case TRFCR_ELx_TS_VIRTUAL: + case TRFCR_ELx_TS_GUEST_PHYSICAL: + case TRFCR_ELx_TS_PHYSICAL: + val = FIELD_GET(TRFCR_ELx_TS_MASK, drvdata->trfcr); + break; + default: + val = -1; + break; + } + +out: + return sysfs_emit(buf, "%d\n", val); +} +static DEVICE_ATTR_RO(ts_source); + static struct attribute *coresight_etmv4_attrs[] = { &dev_attr_nr_pe_cmp.attr, &dev_attr_nr_addr_cmp.attr, @@ -2360,6 +2388,7 @@ static struct attribute *coresight_etmv4_attrs[] = { &dev_attr_vmid_val.attr, &dev_attr_vmid_masks.attr, &dev_attr_cpu.attr, + &dev_attr_ts_source.attr, NULL, };
From: German Gomez german.gomez@arm.com
Sync sysfs documentation pages to include the new ts_source (timestamp source) interface.
Signed-off-by: German Gomez german.gomez@arm.com Signed-off-by: James Clark james.clark@arm.com --- .../ABI/testing/sysfs-bus-coresight-devices-etm4x | 8 ++++++++ .../trace/coresight/coresight-etm4x-reference.rst | 14 ++++++++++++++ 2 files changed, 22 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x index 8e53a32f8150..08b1964f27d3 100644 --- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x +++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x @@ -516,3 +516,11 @@ Contact: Mathieu Poirier mathieu.poirier@linaro.org Description: (Read) Returns the number of special conditional P1 right-hand keys that the trace unit can use (0x194). The value is taken directly from the HW. + +What: /sys/bus/coresight/devices/etm<N>/ts_source +Date: October 2022 +KernelVersion: 6.1 +Contact: Mathieu Poirier mathieu.poirier@linaro.org or Suzuki K Poulose suzuki.poulose@arm.com +Description: (Read) When FEAT_TRF is implemented, value of TRFCR_ELx.TS used for + trace session. Otherwise -1 indicates an unknown time source. Check + trcidr0.tssize to see if a global timestamp is available. diff --git a/Documentation/trace/coresight/coresight-etm4x-reference.rst b/Documentation/trace/coresight/coresight-etm4x-reference.rst index fb7578fd9372..70e34b8c81c1 100644 --- a/Documentation/trace/coresight/coresight-etm4x-reference.rst +++ b/Documentation/trace/coresight/coresight-etm4x-reference.rst @@ -71,6 +71,20 @@
----
+:File: ``ts_source`` (ro) +:Trace Registers: None. +:Notes: + When FEAT_TRF is implemented, value of TRFCR_ELx.TS used for trace session. Otherwise -1 + indicates an unknown time source. Check trcidr0.tssize to see if a global timestamp is + available. + +:Example: + ``$> cat ts_source`` + + ``$> 1`` + +---- + :File: ``addr_idx`` (rw) :Trace Registers: None. :Notes:
-
James Clark