Timestamps in the trace data appear as all zeros on recent kernels, although the feature works correctly on old kernels (e.g., v6.12).

Since commit c382ee674c8b ("arm64/sysreg/tools: Move TRFCR definitions to sysreg"), the TRFCR_ELx_TS_{VIRTUAL|GUEST_PHYSICAL|PHYSICAL} macros were updated to remove the bit shift. As a result, the driver no longer shifts bits when operates the timestamp field.

Fix this by using the FIELD_PREP() and FIELD_GET() helpers.

Reported-by: Tamas Zsoldos tamas.zsoldos@arm.com Fixes: c382ee674c8b ("arm64/sysreg/tools: Move TRFCR definitions to sysreg") Signed-off-by: Leo Yan leo.yan@arm.com --- drivers/hwtracing/coresight/coresight-etm4x-core.c | 2 +- drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 6a5898355a83..acb4a58e4bb9 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -1237,7 +1237,7 @@ static void cpu_detect_trace_filtering(struct etmv4_drvdata *drvdata) * tracing at the kernel EL and EL0, forcing to use the * virtual time as the timestamp. */ - trfcr = (TRFCR_EL1_TS_VIRTUAL | + trfcr = (FIELD_PREP(TRFCR_EL1_TS_MASK, TRFCR_EL1_TS_VIRTUAL) | TRFCR_EL1_ExTRE | TRFCR_EL1_E0TRE);

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c index 49d5fb87a74b..ab251865b893 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c @@ -2320,11 +2320,11 @@ static ssize_t ts_source_show(struct device *dev, goto out; }

- switch (drvdata->trfcr & TRFCR_EL1_TS_MASK) { + val = FIELD_GET(TRFCR_EL1_TS_MASK, drvdata->trfcr); + switch (val) { case TRFCR_EL1_TS_VIRTUAL: case TRFCR_EL1_TS_GUEST_PHYSICAL: case TRFCR_EL1_TS_PHYSICAL: - val = FIELD_GET(TRFCR_EL1_TS_MASK, drvdata->trfcr); break; default: val = -1;

As TS == 0b00 is a valid value, this commit updates to return the value directly instead of converting it to -1.

Currently, only the virtual timestamp (0b01) is used, and other modes are not enabled. Therefore, this change is safe for user space tools.

Signed-off-by: Leo Yan leo.yan@arm.com --- drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 18 +++--------------- 1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c index ab251865b893..894393e7d90b 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c @@ -2315,23 +2315,11 @@ static ssize_t ts_source_show(struct device *dev, int val; struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);

- if (!drvdata->trfcr) { + if (!drvdata->trfcr) val = -1; - goto out; - } - - val = FIELD_GET(TRFCR_EL1_TS_MASK, drvdata->trfcr); - switch (val) { - case TRFCR_EL1_TS_VIRTUAL: - case TRFCR_EL1_TS_GUEST_PHYSICAL: - case TRFCR_EL1_TS_PHYSICAL: - break; - default: - val = -1; - break; - } + else + val = FIELD_GET(TRFCR_EL1_TS_MASK, drvdata->trfcr);

-out: return sysfs_emit(buf, "%d\n", val); } static DEVICE_ATTR_RO(ts_source);