The current ETM4x configuration via sysfs can lead to several inconsistencies:
- If the configuration is modified via sysfs while a perf session is active, the running configuration may differ before a sched-out and after a subsequent sched-in.
- If a perf session and a sysfs session enable tracing concurrently, the configuration from configfs may become corrupted.
- There is a risk of corrupting drvdata->config if a perf session enables tracing while cscfg_csdev_disable_active_config() is being handled in etm4_disable_sysfs().
To resolve these issues, separate the configuration into:
- active_config: the configuration applied to the current session - config: the configuration set via sysfs
Additionally:
- Apply the configuration from configfs after taking the appropriate mode.
- Since active_config and related fields are accessed only by the local CPU in etm4_enable/disable_sysfs_smp_call() (similar to perf enable/disable), remove the lock/unlock from the sysfs enable/disable path and startup/dying_cpu except when to access config fields.
Fixes: 54ff892b76c6 ("coresight: etm4x: splitting struct etmv4_drvdata") Signed-off-by: Yeoreum Yun yeoreum.yun@arm.com --- .../hwtracing/coresight/coresight-etm4x-cfg.c | 2 +- .../coresight/coresight-etm4x-core.c | 103 ++++++++++-------- drivers/hwtracing/coresight/coresight-etm4x.h | 2 + 3 files changed, 58 insertions(+), 49 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-cfg.c b/drivers/hwtracing/coresight/coresight-etm4x-cfg.c index 9b4947d75fde..9d56e17e09b1 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;
if (((offset >= TRCEVENTCTL0R) && (offset <= TRCVIPCSSCTLR)) || diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 2798604943ed..31ac7783fdb8 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -245,6 +245,7 @@ void etm4_release_trace_id(struct etmv4_drvdata *drvdata) struct etm4_enable_arg { struct etmv4_drvdata *drvdata; struct coresight_path *path; + struct etmv4_config config; int rc; };
@@ -270,10 +271,11 @@ static void etm4x_prohibit_trace(struct etmv4_drvdata *drvdata) static u64 etm4x_get_kern_user_filter(struct etmv4_drvdata *drvdata) { u64 trfcr = drvdata->trfcr; + struct etmv4_config *config = &drvdata->active_config;
- if (drvdata->config.mode & ETM_MODE_EXCL_KERN) + if (config->mode & ETM_MODE_EXCL_KERN) trfcr &= ~TRFCR_EL1_ExTRE; - if (drvdata->config.mode & ETM_MODE_EXCL_USER) + if (config->mode & ETM_MODE_EXCL_USER) trfcr &= ~TRFCR_EL1_E0TRE;
return trfcr; @@ -281,7 +283,7 @@ static u64 etm4x_get_kern_user_filter(struct etmv4_drvdata *drvdata)
/* * etm4x_allow_trace - Allow CPU tracing in the respective ELs, - * as configured by the drvdata->config.mode for the current + * as configured by the drvdata->active_config.mode for the current * session. Even though we have TRCVICTLR bits to filter the * trace in the ELs, it doesn't prevent the ETM from generating * a packet (e.g, TraceInfo) that might contain the addresses from @@ -292,12 +294,13 @@ static u64 etm4x_get_kern_user_filter(struct etmv4_drvdata *drvdata) static void etm4x_allow_trace(struct etmv4_drvdata *drvdata) { u64 trfcr, guest_trfcr; + struct etmv4_config *config = &drvdata->active_config;
/* If the CPU doesn't support FEAT_TRF, nothing to do */ if (!drvdata->trfcr) return;
- if (drvdata->config.mode & ETM_MODE_EXCL_HOST) + if (config->mode & ETM_MODE_EXCL_HOST) trfcr = drvdata->trfcr & ~(TRFCR_EL1_ExTRE | TRFCR_EL1_E0TRE); else trfcr = etm4x_get_kern_user_filter(drvdata); @@ -305,7 +308,7 @@ static void etm4x_allow_trace(struct etmv4_drvdata *drvdata) write_trfcr(trfcr);
/* Set filters for guests and pass to KVM */ - if (drvdata->config.mode & ETM_MODE_EXCL_GUEST) + if (config->mode & ETM_MODE_EXCL_GUEST) guest_trfcr = drvdata->trfcr & ~(TRFCR_EL1_ExTRE | TRFCR_EL1_E0TRE); else guest_trfcr = etm4x_get_kern_user_filter(drvdata); @@ -499,7 +502,7 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata) { int i, rc; 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 device *etm_dev = &csdev->dev; struct csdev_access *csa = &csdev->access; @@ -619,27 +622,52 @@ 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; + unsigned long cfg_hash; + int preset;
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 = arg->config;
- /* The tracer didn't start */ + /* enable any config activated by configfs */ + cscfg_config_sysfs_get_active_cfg(&cfg_hash, &preset); + if (cfg_hash) { + arg->rc = cscfg_csdev_enable_active_config(csdev, + cfg_hash, + preset); + if (arg->rc) + goto err; + } + + drvdata->trcid = arg->path->trace_id; + + /* Tracer will never be paused in sysfs mode */ + drvdata->paused = false; + + arg->rc = etm4_enable_hw(drvdata); if (arg->rc) { - coresight_set_mode(csdev, CS_MODE_DISABLED); - return; + cscfg_csdev_disable_active_config(csdev); + goto err; }
+ drvdata->sticky_enable = true; csdev->path = arg->path; + + return; +err: + /* The tracer didn't start */ + coresight_set_mode(csdev, CS_MODE_DISABLED); }
/* @@ -677,7 +705,7 @@ 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) @@ -761,7 +789,7 @@ 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, }; @@ -922,25 +950,7 @@ static int etm4_enable_sysfs(struct coresight_device *csdev, struct coresight_pa { struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); struct etm4_enable_arg arg = { }; - unsigned long cfg_hash; - int ret, preset; - - /* 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) { - etm4_release_trace_id(drvdata); - return ret; - } - } - - raw_spin_lock(&drvdata->spinlock); - - drvdata->trcid = path->trace_id; - - /* Tracer will never be paused in sysfs mode */ - drvdata->paused = false; + int ret;
/* * Executing etm4_enable_hw on the cpu whose ETM is being enabled @@ -948,20 +958,20 @@ static int etm4_enable_sysfs(struct coresight_device *csdev, struct coresight_pa */ arg.drvdata = drvdata; arg.path = path; + + raw_spin_lock(&drvdata->spinlock); + arg.config = drvdata->config; + raw_spin_unlock(&drvdata->spinlock); + ret = smp_call_function_single(drvdata->cpu, etm4_enable_sysfs_smp_call, &arg, 1); if (!ret) ret = arg.rc; if (!ret) - drvdata->sticky_enable = true; - - if (ret) + dev_dbg(&csdev->dev, "ETM tracing enabled\n"); + else etm4_release_trace_id(drvdata);
- raw_spin_unlock(&drvdata->spinlock); - - if (!ret) - dev_dbg(&csdev->dev, "ETM tracing enabled\n"); return ret; }
@@ -1048,7 +1058,7 @@ 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; @@ -1090,7 +1100,10 @@ static void etm4_disable_sysfs_smp_call(void *info)
etm4_disable_hw(drvdata);
+ cscfg_csdev_disable_active_config(drvdata->csdev); + drvdata->csdev->path = NULL; + coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED); }
@@ -1135,8 +1148,6 @@ static void etm4_disable_sysfs(struct coresight_device *csdev) { struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
- raw_spin_lock(&drvdata->spinlock); - /* * Executing etm4_disable_hw on the cpu whose ETM is being disabled * ensures that register writes occur when cpu is powered. @@ -1144,10 +1155,6 @@ static void etm4_disable_sysfs(struct coresight_device *csdev) smp_call_function_single(drvdata->cpu, etm4_disable_sysfs_smp_call, drvdata, 1);
- raw_spin_unlock(&drvdata->spinlock); - - cscfg_csdev_disable_active_config(csdev); - /* * we only release trace IDs when resetting sysfs. * This permits sysfs users to read the trace ID after the trace @@ -1704,7 +1711,7 @@ 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 @@ -1746,7 +1753,7 @@ static int etm4_set_event_filters(struct etmv4_drvdata *drvdata, int i, comparator, ret = 0; u64 address; const struct etmv4_caps *caps = &drvdata->caps; - struct etmv4_config *config = &drvdata->config; + struct etmv4_config *config = &drvdata->active_config; struct etm_filters *filters = event->hw.addr_filters;
if (!filters) diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h index c0f7da17a186..a974e4d05838 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.h +++ b/drivers/hwtracing/coresight/coresight-etm4x.h @@ -1068,6 +1068,7 @@ 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; u32 ss_status[ETM_MAX_SS_CMP];