| Message ID | 20220704081149.16797-5-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 04/07/2022 09:11, Mike Leach wrote: > The trace ID API is now used to allocate trace IDs for ETM4.x / ETE > devices. > > For perf sessions, these will be allocated on enable, and released on > disable. > > For sysfs sessions, these will be allocated on enable, but only released > on reset. This allows the sysfs session to interrogate the Trace ID used > after the session is over - maintaining functional consistency with the > previous allocation scheme. > > The trace ID will also be allocated on read of the mgmt/trctraceid file. > This ensures that if perf or sysfs read this before enabling trace, the > value will be the one used for the trace session. > > Trace ID initialisation is removed from the _probe() function. > > Signed-off-by: Mike Leach <mike.leach@linaro.org> > --- > .../coresight/coresight-etm4x-core.c | 65 +++++++++++++++++-- > .../coresight/coresight-etm4x-sysfs.c | 32 ++++++++- > drivers/hwtracing/coresight/coresight-etm4x.h | 3 + > 3 files changed, 91 insertions(+), 9 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c > index 87299e99dabb..3f4f7ddd14ec 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c > @@ -42,6 +42,7 @@ > #include "coresight-etm4x-cfg.h" > #include "coresight-self-hosted-trace.h" > #include "coresight-syscfg.h" > +#include "coresight-trace-id.h" > > static int boot_enable; > module_param(boot_enable, int, 0444); > @@ -234,6 +235,38 @@ static int etm4_trace_id(struct coresight_device *csdev) > return drvdata->trcid; > } > > +int etm4_read_alloc_trace_id(struct etmv4_drvdata *drvdata) > +{ > + int trace_id; > + > + /* > + * This will allocate a trace ID to the cpu, > + * or return the one currently allocated. > + */ > + spin_lock(&drvdata->spinlock); > + trace_id = drvdata->trcid; > + if (!trace_id) { > + trace_id = coresight_trace_id_get_cpu_id(drvdata->cpu); > + if (trace_id > 0) > + drvdata->trcid = (u8)trace_id; > + } > + spin_unlock(&drvdata->spinlock); > + > + if (trace_id <= 0) > + pr_err("Failed to allocate trace ID for %s on CPU%d\n", > + dev_name(&drvdata->csdev->dev), drvdata->cpu); dev_err(&drvdata->csdev->dev, ....); > + > + return trace_id; > +} > + > +void etm4_release_trace_id(struct etmv4_drvdata *drvdata) > +{ > + spin_lock(&drvdata->spinlock); > + coresight_trace_id_put_cpu_id(drvdata->cpu); > + drvdata->trcid = 0; > + spin_unlock(&drvdata->spinlock); > +} > + > struct etm4_enable_arg { > struct etmv4_drvdata *drvdata; > int rc; > @@ -715,9 +748,18 @@ static int etm4_enable_perf(struct coresight_device *csdev, > ret = etm4_parse_event_config(csdev, event); > if (ret) > goto out; > + > + /* allocate a trace ID */ > + ret = etm4_read_alloc_trace_id(drvdata); > + if (ret < 0) > + goto out; > + > /* And enable it */ > ret = etm4_enable_hw(drvdata); > > + /* failed to enable */ > + if (ret) > + etm4_release_trace_id(drvdata); > out: > return ret; > } > @@ -737,6 +779,11 @@ static int etm4_enable_sysfs(struct coresight_device *csdev) > return ret; > } > > + /* allocate a trace ID */ > + ret = etm4_read_alloc_trace_id(drvdata); > + if (ret < 0) > + return ret; > + > spin_lock(&drvdata->spinlock); > > /* > @@ -754,6 +801,8 @@ static int etm4_enable_sysfs(struct coresight_device *csdev) > > if (!ret) > dev_dbg(&csdev->dev, "ETM tracing enabled\n"); > + else > + etm4_release_trace_id(drvdata); > return ret; > } > > @@ -881,6 +930,9 @@ static int etm4_disable_perf(struct coresight_device *csdev, > /* TRCVICTLR::SSSTATUS, bit[9] */ > filters->ssstatus = (control & BIT(9)); > > + /* release trace ID - this may pend release if perf session is still active */ > + etm4_release_trace_id(drvdata); > + > return 0; > } > > @@ -906,6 +958,13 @@ static void etm4_disable_sysfs(struct coresight_device *csdev) > spin_unlock(&drvdata->spinlock); > cpus_read_unlock(); > > + /* > + * unlike for perf session - 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"); > } > > @@ -1548,11 +1607,6 @@ static int etm4_dying_cpu(unsigned int cpu) > return 0; > } > > -static void etm4_init_trace_id(struct etmv4_drvdata *drvdata) > -{ > - drvdata->trcid = coresight_get_trace_id(drvdata->cpu); > -} > - > static int __etm4_cpu_save(struct etmv4_drvdata *drvdata) > { > int i, ret = 0; > @@ -1957,7 +2011,6 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid) > if (!desc.name) > return -ENOMEM; > > - etm4_init_trace_id(drvdata); > etm4_set_default(&drvdata->config); > > pdata = coresight_get_platform_data(dev); > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c > index 6ea8181816fc..c7f896a020d9 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c > +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c > @@ -266,10 +266,11 @@ static ssize_t reset_store(struct device *dev, > config->vmid_mask0 = 0x0; > config->vmid_mask1 = 0x0; > > - drvdata->trcid = drvdata->cpu + 1; > - > spin_unlock(&drvdata->spinlock); > > + /* for sysfs - only release trace id when resetting */ > + etm4_release_trace_id(drvdata); > + > cscfg_csdev_reset_feats(to_coresight_device(dev)); > > return size; > @@ -2363,6 +2364,31 @@ static struct attribute *coresight_etmv4_attrs[] = { > NULL, > }; > > +/* > + * Trace ID allocated dynamically on enable - but also allocate on read > + * in case sysfs or perf read before enable to ensure consistent metadata > + * information for trace decode > + */ > +static ssize_t trctraceid_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + int trace_id; > + struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent); > + > + trace_id = etm4_read_alloc_trace_id(drvdata); > + if (trace_id < 0) > + return trace_id; > + > + return scnprintf(buf, PAGE_SIZE, "0x%x\n", trace_id); nit: sysfs_emit(buf, "0x%x\n", trace_id); > +} > + > +/* mgmt group uses extended attributes - no standard macro available */ That doesn't prevent us from using dev_attribute for traceid. In the end, mgmt group is a collection of "struct attribute *". All it matters is for the "show" function to decode how to print the value from the "attribute". You should be able to use DEVICE_ATTR_RO here ... > +static struct dev_ext_attribute dev_attr_trctraceid = { > + __ATTR(trctraceid, 0444, trctraceid_show, NULL), > + (void *)(unsigned long)TRCTRACEIDR > +}; > + ... and get rid of this. Otherwise looks fine to me. Suzuki > struct etmv4_reg { > struct coresight_device *csdev; > u32 offset; > @@ -2499,7 +2525,7 @@ static struct attribute *coresight_etmv4_mgmt_attrs[] = { > coresight_etm4x_reg(trcpidr3, TRCPIDR3), > coresight_etm4x_reg(trcoslsr, TRCOSLSR), > coresight_etm4x_reg(trcconfig, TRCCONFIGR), > - coresight_etm4x_reg(trctraceid, TRCTRACEIDR), > + &dev_attr_trctraceid.attr.attr, > coresight_etm4x_reg(trcdevarch, TRCDEVARCH), > NULL, > }; > diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h > index 33869c1d20c3..e0a9d334375d 100644 > --- a/drivers/hwtracing/coresight/coresight-etm4x.h > +++ b/drivers/hwtracing/coresight/coresight-etm4x.h > @@ -1094,4 +1094,7 @@ static inline bool etm4x_is_ete(struct etmv4_drvdata *drvdata) > { > return drvdata->arch >= ETM_ARCH_ETE; > } > + > +int etm4_read_alloc_trace_id(struct etmv4_drvdata *drvdata); > +void etm4_release_trace_id(struct etmv4_drvdata *drvdata); > #endif
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 87299e99dabb..3f4f7ddd14ec 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -42,6 +42,7 @@ #include "coresight-etm4x-cfg.h" #include "coresight-self-hosted-trace.h" #include "coresight-syscfg.h" +#include "coresight-trace-id.h" static int boot_enable; module_param(boot_enable, int, 0444); @@ -234,6 +235,38 @@ static int etm4_trace_id(struct coresight_device *csdev) return drvdata->trcid; } +int etm4_read_alloc_trace_id(struct etmv4_drvdata *drvdata) +{ + int trace_id; + + /* + * This will allocate a trace ID to the cpu, + * or return the one currently allocated. + */ + spin_lock(&drvdata->spinlock); + trace_id = drvdata->trcid; + if (!trace_id) { + trace_id = coresight_trace_id_get_cpu_id(drvdata->cpu); + if (trace_id > 0) + drvdata->trcid = (u8)trace_id; + } + spin_unlock(&drvdata->spinlock); + + if (trace_id <= 0) + pr_err("Failed to allocate trace ID for %s on CPU%d\n", + dev_name(&drvdata->csdev->dev), drvdata->cpu); + + return trace_id; +} + +void etm4_release_trace_id(struct etmv4_drvdata *drvdata) +{ + spin_lock(&drvdata->spinlock); + coresight_trace_id_put_cpu_id(drvdata->cpu); + drvdata->trcid = 0; + spin_unlock(&drvdata->spinlock); +} + struct etm4_enable_arg { struct etmv4_drvdata *drvdata; int rc; @@ -715,9 +748,18 @@ static int etm4_enable_perf(struct coresight_device *csdev, ret = etm4_parse_event_config(csdev, event); if (ret) goto out; + + /* allocate a trace ID */ + ret = etm4_read_alloc_trace_id(drvdata); + if (ret < 0) + goto out; + /* And enable it */ ret = etm4_enable_hw(drvdata); + /* failed to enable */ + if (ret) + etm4_release_trace_id(drvdata); out: return ret; } @@ -737,6 +779,11 @@ static int etm4_enable_sysfs(struct coresight_device *csdev) return ret; } + /* allocate a trace ID */ + ret = etm4_read_alloc_trace_id(drvdata); + if (ret < 0) + return ret; + spin_lock(&drvdata->spinlock); /* @@ -754,6 +801,8 @@ static int etm4_enable_sysfs(struct coresight_device *csdev) if (!ret) dev_dbg(&csdev->dev, "ETM tracing enabled\n"); + else + etm4_release_trace_id(drvdata); return ret; } @@ -881,6 +930,9 @@ static int etm4_disable_perf(struct coresight_device *csdev, /* TRCVICTLR::SSSTATUS, bit[9] */ filters->ssstatus = (control & BIT(9)); + /* release trace ID - this may pend release if perf session is still active */ + etm4_release_trace_id(drvdata); + return 0; } @@ -906,6 +958,13 @@ static void etm4_disable_sysfs(struct coresight_device *csdev) spin_unlock(&drvdata->spinlock); cpus_read_unlock(); + /* + * unlike for perf session - 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"); } @@ -1548,11 +1607,6 @@ static int etm4_dying_cpu(unsigned int cpu) return 0; } -static void etm4_init_trace_id(struct etmv4_drvdata *drvdata) -{ - drvdata->trcid = coresight_get_trace_id(drvdata->cpu); -} - static int __etm4_cpu_save(struct etmv4_drvdata *drvdata) { int i, ret = 0; @@ -1957,7 +2011,6 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid) if (!desc.name) return -ENOMEM; - etm4_init_trace_id(drvdata); etm4_set_default(&drvdata->config); pdata = coresight_get_platform_data(dev); diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c index 6ea8181816fc..c7f896a020d9 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c @@ -266,10 +266,11 @@ static ssize_t reset_store(struct device *dev, config->vmid_mask0 = 0x0; config->vmid_mask1 = 0x0; - drvdata->trcid = drvdata->cpu + 1; - spin_unlock(&drvdata->spinlock); + /* for sysfs - only release trace id when resetting */ + etm4_release_trace_id(drvdata); + cscfg_csdev_reset_feats(to_coresight_device(dev)); return size; @@ -2363,6 +2364,31 @@ static struct attribute *coresight_etmv4_attrs[] = { NULL, }; +/* + * Trace ID allocated dynamically on enable - but also allocate on read + * in case sysfs or perf read before enable to ensure consistent metadata + * information for trace decode + */ +static ssize_t trctraceid_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + int trace_id; + struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent); + + trace_id = etm4_read_alloc_trace_id(drvdata); + if (trace_id < 0) + return trace_id; + + return scnprintf(buf, PAGE_SIZE, "0x%x\n", trace_id); +} + +/* mgmt group uses extended attributes - no standard macro available */ +static struct dev_ext_attribute dev_attr_trctraceid = { + __ATTR(trctraceid, 0444, trctraceid_show, NULL), + (void *)(unsigned long)TRCTRACEIDR +}; + struct etmv4_reg { struct coresight_device *csdev; u32 offset; @@ -2499,7 +2525,7 @@ static struct attribute *coresight_etmv4_mgmt_attrs[] = { coresight_etm4x_reg(trcpidr3, TRCPIDR3), coresight_etm4x_reg(trcoslsr, TRCOSLSR), coresight_etm4x_reg(trcconfig, TRCCONFIGR), - coresight_etm4x_reg(trctraceid, TRCTRACEIDR), + &dev_attr_trctraceid.attr.attr, coresight_etm4x_reg(trcdevarch, TRCDEVARCH), NULL, }; diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h index 33869c1d20c3..e0a9d334375d 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.h +++ b/drivers/hwtracing/coresight/coresight-etm4x.h @@ -1094,4 +1094,7 @@ static inline bool etm4x_is_ete(struct etmv4_drvdata *drvdata) { return drvdata->arch >= ETM_ARCH_ETE; } + +int etm4_read_alloc_trace_id(struct etmv4_drvdata *drvdata); +void etm4_release_trace_id(struct etmv4_drvdata *drvdata); #endif
The trace ID API is now used to allocate trace IDs for ETM4.x / ETE devices. For perf sessions, these will be allocated on enable, and released on disable. For sysfs sessions, these will be allocated on enable, but only released on reset. This allows the sysfs session to interrogate the Trace ID used after the session is over - maintaining functional consistency with the previous allocation scheme. The trace ID will also be allocated on read of the mgmt/trctraceid file. This ensures that if perf or sysfs read this before enabling trace, the value will be the one used for the trace session. Trace ID initialisation is removed from the _probe() function. Signed-off-by: Mike Leach <mike.leach@linaro.org> --- .../coresight/coresight-etm4x-core.c | 65 +++++++++++++++++-- .../coresight/coresight-etm4x-sysfs.c | 32 ++++++++- drivers/hwtracing/coresight/coresight-etm4x.h | 3 + 3 files changed, 91 insertions(+), 9 deletions(-)