Set and clear the path pointer on the target CPU during ETM enable and disable operations to avoid race conditions when retrieving the pointer in CPU PM callbacks.
Tested-by: James Clark james.clark@linaro.org Reviewed-by: Yeoreum Yun yeoreum.yun@arm.com Reviewed-by: James Clark james.clark@linaro.org Signed-off-by: Leo Yan leo.yan@arm.com --- drivers/hwtracing/coresight/coresight-etm4x-core.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 4a9b226781a5c2ab6efcadf08614de58bcd4043a..1f100e8bbcc775a1bdc5f8b27ff15dbcaf030a63 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -234,6 +234,7 @@ void etm4_release_trace_id(struct etmv4_drvdata *drvdata)
struct etm4_enable_arg { struct etmv4_drvdata *drvdata; + struct coresight_path *path; int rc; };
@@ -621,8 +622,12 @@ static void etm4_enable_sysfs_smp_call(void *info) arg->rc = etm4_enable_hw(arg->drvdata);
/* The tracer didn't start */ - if (arg->rc) + if (arg->rc) { coresight_set_mode(csdev, CS_MODE_DISABLED); + return; + } + + csdev->path = arg->path; }
/* @@ -890,9 +895,13 @@ static int etm4_enable_perf(struct coresight_device *csdev,
out: /* Failed to start tracer; roll back to DISABLED mode */ - if (ret) + if (ret) { coresight_set_mode(csdev, CS_MODE_DISABLED); - return ret; + return ret; + } + + csdev->path = path; + return 0; }
static int etm4_enable_sysfs(struct coresight_device *csdev, struct coresight_path *path) @@ -922,6 +931,7 @@ static int etm4_enable_sysfs(struct coresight_device *csdev, struct coresight_pa * ensures that register writes occur when cpu is powered. */ arg.drvdata = drvdata; + arg.path = path; ret = smp_call_function_single(drvdata->cpu, etm4_enable_sysfs_smp_call, &arg, 1); if (!ret) @@ -1063,6 +1073,7 @@ static void etm4_disable_sysfs_smp_call(void *info)
etm4_disable_hw(drvdata);
+ drvdata->csdev->path = NULL; coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED); }
@@ -1092,6 +1103,7 @@ static int etm4_disable_perf(struct coresight_device *csdev, /* TRCVICTLR::SSSTATUS, bit[9] */ filters->ssstatus = (control & BIT(9));
+ drvdata->csdev->path = NULL; coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED);
/*