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charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260413_000629_111740_2A05A4E8 X-CRM114-Status: GOOD ( 33.88 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Jie, > Hi Yeoreum, > > On 4/13/2026 1:55 AM, Yeoreum Yun wrote: > > The current ETM4x configuration via sysfs can lead to the following > > inconsistencies: > > > > - If a configuration is modified via sysfs while a perf session is > > active, the running configuration may differ between before > > a sched-out and after a subsequent sched-in. > > > > - If a perf session and sysfs session tries to enable concurrently, > > configuration from configfs could be corrupted. > > > > - There is chance to corrupt drvdata->config if perf session tries > > to enabled among handling cscfg_csdev_disable_active_config() > > in etm4_disable_sysfs(). > > > > To resolve these inconsistencies, the configuration should be separated into: > > > > - active_config, which is applied configuration for the current session > > - config, which stores the settings configured via sysfs. > > > > and apply configuration from configfs after taking a mode. > > typo in subject: > s/configration/configuration Thanks. > > > > > Signed-off-by: Yeoreum Yun > > --- > > .../hwtracing/coresight/coresight-etm4x-cfg.c | 2 +- > > .../coresight/coresight-etm4x-core.c | 74 ++++++++++++------- > > drivers/hwtracing/coresight/coresight-etm4x.h | 2 + > > 3 files changed, 49 insertions(+), 29 deletions(-) > > > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-cfg.c b/drivers/hwtracing/coresight/coresight-etm4x-cfg.c > > index d14d7c8a23e5..0553771d04e7 100644 > > --- a/drivers/hwtracing/coresight/coresight-etm4x-cfg.c > > +++ b/drivers/hwtracing/coresight/coresight-etm4x-cfg.c > > @@ -47,7 +47,7 @@ static int etm4_cfg_map_reg_offset(struct etmv4_drvdata *drvdata, > > struct cscfg_regval_csdev *reg_csdev, u32 offset) > > { > > int err = -EINVAL, idx; > > - struct etmv4_config *drvcfg = &drvdata->config; > > + struct etmv4_config *drvcfg = &drvdata->active_config; > > u32 off_mask; > > <...> > > > struct device *etm_dev = &csdev->dev; > > struct csdev_access *csa = &csdev->access; > > @@ -616,19 +621,36 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata) > > static void etm4_enable_sysfs_smp_call(void *info) > > { > > struct etm4_enable_arg *arg = info; > > + struct etmv4_drvdata *drvdata; > > struct coresight_device *csdev; > > if (WARN_ON(!arg)) > > return; > > - csdev = arg->drvdata->csdev; > > + drvdata = arg->drvdata; > > + csdev = drvdata->csdev; > > if (!coresight_take_mode(csdev, CS_MODE_SYSFS)) { > > /* Someone is already using the tracer */ > > arg->rc = -EBUSY; > > return; > > } > > - arg->rc = etm4_enable_hw(arg->drvdata); > > + drvdata->active_config = drvdata->config; > > + > > + if (arg->cfg_hash) { > > + arg->rc = cscfg_csdev_enable_active_config(csdev, > > + arg->cfg_hash, > > + arg->preset); > > + if (arg->rc) > > we need reset the mode once enable failed before return. > coresight_set_mode(csdev, CS_MODE_DISABLED); Good catch. also missing some fix more for deadlock. I'll send again. Thanks! > > Thanks, > Jie > > > + return; > > + } > > + > > + drvdata->trcid = arg->trace_id; > > + > > + /* Tracer will never be paused in sysfs mode */ > > + drvdata->paused = false; > > + > > + arg->rc = etm4_enable_hw(drvdata); > > /* The tracer didn't start */ > > if (arg->rc) > > @@ -670,7 +692,7 @@ static int etm4_config_timestamp_event(struct etmv4_drvdata *drvdata, > > int ctridx; > > int rselector; > > const struct etmv4_caps *caps = &drvdata->caps; > > - struct etmv4_config *config = &drvdata->config; > > + struct etmv4_config *config = &drvdata->active_config; > > /* No point in trying if we don't have at least one counter */ > > if (!caps->nr_cntr) > > @@ -754,7 +776,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev, > > int ret = 0; > > struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); > > const struct etmv4_caps *caps = &drvdata->caps; > > - struct etmv4_config *config = &drvdata->config; > > + struct etmv4_config *config = &drvdata->active_config; > > struct perf_event_attr max_timestamp = { > > .ATTR_CFG_FLD_timestamp_CFG = U64_MAX, > > }; > > @@ -916,24 +938,18 @@ static int etm4_enable_sysfs(struct coresight_device *csdev, struct coresight_pa > > /* enable any config activated by configfs */ > > cscfg_config_sysfs_get_active_cfg(&cfg_hash, &preset); > > - if (cfg_hash) { > > - ret = cscfg_csdev_enable_active_config(csdev, cfg_hash, preset); > > - if (ret) > > - return ret; > > - } > > raw_spin_lock(&drvdata->spinlock); > > - drvdata->trcid = path->trace_id; > > - > > - /* Tracer will never be paused in sysfs mode */ > > - drvdata->paused = false; > > - > > /* > > * Executing etm4_enable_hw on the cpu whose ETM is being enabled > > * ensures that register writes occur when cpu is powered. > > */ > > arg.drvdata = drvdata; > > + arg.cfg_hash = cfg_hash; > > + arg.preset = preset; > > + arg.trace_id = path->trace_id; > > + > > ret = smp_call_function_single(drvdata->cpu, > > etm4_enable_sysfs_smp_call, &arg, 1); > > if (!ret) > > @@ -1034,7 +1050,7 @@ static void etm4_disable_hw(struct etmv4_drvdata *drvdata) > > { > > u32 control; > > const struct etmv4_caps *caps = &drvdata->caps; > > - struct etmv4_config *config = &drvdata->config; > > + struct etmv4_config *config = &drvdata->active_config; > > struct coresight_device *csdev = drvdata->csdev; > > struct csdev_access *csa = &csdev->access; > > int i; > > @@ -1070,6 +1086,8 @@ static void etm4_disable_sysfs_smp_call(void *info) > > etm4_disable_hw(drvdata); > > + cscfg_csdev_disable_active_config(drvdata->csdev); > > + > > coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED); > > } > > @@ -1130,9 +1148,6 @@ static void etm4_disable_sysfs(struct coresight_device *csdev) > > drvdata, 1); > > raw_spin_unlock(&drvdata->spinlock); > > - > > - cscfg_csdev_disable_active_config(csdev); > > - > > cpus_read_unlock(); > > /* > > @@ -1375,6 +1390,7 @@ static void etm4_init_arch_data(void *info) > > struct etm4_init_arg *init_arg = info; > > struct etmv4_drvdata *drvdata; > > struct etmv4_caps *caps; > > + struct etmv4_config *config; > > struct csdev_access *csa; > > struct device *dev = init_arg->dev; > > int i; > > @@ -1382,6 +1398,7 @@ static void etm4_init_arch_data(void *info) > > drvdata = dev_get_drvdata(init_arg->dev); > > caps = &drvdata->caps; > > csa = init_arg->csa; > > + config = &drvdata->active_config; > > /* > > * If we are unable to detect the access mechanism, > > @@ -1442,7 +1459,7 @@ static void etm4_init_arch_data(void *info) > > /* EXLEVEL_S, bits[19:16] Secure state instruction tracing */ > > caps->s_ex_level = FIELD_GET(TRCIDR3_EXLEVEL_S_MASK, etmidr3); > > - drvdata->config.s_ex_level = caps->s_ex_level; > > + config->s_ex_level = caps->s_ex_level; > > /* EXLEVEL_NS, bits[23:20] Non-secure state instruction tracing */ > > caps->ns_ex_level = FIELD_GET(TRCIDR3_EXLEVEL_NS_MASK, etmidr3); > > /* > > @@ -1687,7 +1704,7 @@ static void etm4_set_default(struct etmv4_config *config) > > static int etm4_get_next_comparator(struct etmv4_drvdata *drvdata, u32 type) > > { > > int nr_comparator, index = 0; > > - struct etmv4_config *config = &drvdata->config; > > + struct etmv4_config *config = &drvdata->active_config; > > /* > > * nr_addr_cmp holds the number of comparator _pair_, so time 2 > > @@ -1728,7 +1745,7 @@ static int etm4_set_event_filters(struct etmv4_drvdata *drvdata, > > { > > int i, comparator, ret = 0; > > u64 address; > > - struct etmv4_config *config = &drvdata->config; > > + struct etmv4_config *config = &drvdata->active_config; > > struct etm_filters *filters = event->hw.addr_filters; > > if (!filters) > > @@ -2250,7 +2267,8 @@ static int etm4_add_coresight_dev(struct etm4_init_arg *init_arg) > > if (!desc.name) > > return -ENOMEM; > > - etm4_set_default(&drvdata->config); > > + etm4_set_default(&drvdata->active_config); > > + drvdata->config = drvdata->active_config; > > pdata = coresight_get_platform_data(dev); > > if (IS_ERR(pdata)) > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h > > index 3cc1ca76c933..b943c28c9c71 100644 > > --- a/drivers/hwtracing/coresight/coresight-etm4x.h > > +++ b/drivers/hwtracing/coresight/coresight-etm4x.h > > @@ -1069,6 +1069,7 @@ struct etmv4_save_state { > > * allows tracing at all ELs. We don't want to compute this > > * at runtime, due to the additional setting of TRFCR_CX when > > * in EL2. Otherwise, 0. > > + * @active_config: structure holding current applied configuration parameters. > > * @config: structure holding configuration parameters. > > * @save_state: State to be preserved across power loss > > * @paused: Indicates if the trace unit is paused. > > @@ -1089,6 +1090,7 @@ struct etmv4_drvdata { > > bool os_unlock : 1; > > bool paused : 1; > > u64 trfcr; > > + struct etmv4_config active_config; > > struct etmv4_config config; > > struct etmv4_save_state *save_state; > > DECLARE_BITMAP(arch_features, ETM4_IMPDEF_FEATURE_MAX); > -- Sincerely, Yeoreum Yun