| Message ID | 20221101163103.17921-7-mike.leach@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | coresight: Add new API to allocate trace source ID values | expand |
On 01/11/2022 16:30, Mike Leach wrote: > 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> > --- > drivers/hwtracing/coresight/coresight-etm.h | 2 + > .../coresight/coresight-etm3x-core.c | 69 +++++++++++++++++-- > .../coresight/coresight-etm3x-sysfs.c | 27 ++------ > 3 files changed, 72 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..9a7a9e974d41 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_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_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 +664,9 @@ 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 */ Minor nit: Please split the line. With that Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
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..9a7a9e974d41 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_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_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 +664,9 @@ 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 +691,13 @@ 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 +844,6 @@ 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 +929,6 @@ 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,
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> --- drivers/hwtracing/coresight/coresight-etm.h | 2 + .../coresight/coresight-etm3x-core.c | 69 +++++++++++++++++-- .../coresight/coresight-etm3x-sysfs.c | 27 ++------ 3 files changed, 72 insertions(+), 26 deletions(-)