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,