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:
- curr_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 curr_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.
As the curr_config is used for cfg-configfs, etmv4 doesn't need to set its lock for the cfg-configfs since the curr_config is proceted by cs_mode otherwise it would make a possible cpu-stall when it get interrupt while setting the sysfs configuration.
Therefore, set the drv_spinlock for cfg-configfs as NULL and let the cfg-configfs disable irq without grap drv_spinlock when it is NULL.
Fixes: 54ff892b76c6 ("coresight: etm4x: splitting struct etmv4_drvdata") Tested-by: Leo Yan leo.yan@arm.com Reviewed-by: Mike Leach mike.leach@arm.com Signed-off-by: Yeoreum Yun yeoreum.yun@arm.com --- drivers/hwtracing/coresight/coresight-config.c | 18 ++-- drivers/hwtracing/coresight/coresight-config.h | 22 ++++ drivers/hwtracing/coresight/coresight-etm4x-cfg.c | 13 ++- drivers/hwtracing/coresight/coresight-etm4x-core.c | 117 ++++++++++++--------- .../hwtracing/coresight/coresight-etm4x-sysfs.c | 5 +- drivers/hwtracing/coresight/coresight-etm4x.h | 4 +- 6 files changed, 112 insertions(+), 67 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-config.c b/drivers/hwtracing/coresight/coresight-config.c index 4f72ae71b696..0e296289f286 100644 --- a/drivers/hwtracing/coresight/coresight-config.c +++ b/drivers/hwtracing/coresight/coresight-config.c @@ -73,13 +73,12 @@ static void cscfg_init_reg_param(struct cscfg_feature_csdev *feat_csdev, /* set values into the driver locations referenced in cscfg_reg_csdev */ static int cscfg_set_on_enable(struct cscfg_feature_csdev *feat_csdev) { - unsigned long flags; int i;
- raw_spin_lock_irqsave(feat_csdev->drv_spinlock, flags); - for (i = 0; i < feat_csdev->nr_regs; i++) - cscfg_set_reg(&feat_csdev->regs_csdev[i]); - raw_spin_unlock_irqrestore(feat_csdev->drv_spinlock, flags); + scoped_guard(feat_csdev_lock, feat_csdev) { + for (i = 0; i < feat_csdev->nr_regs; i++) + cscfg_set_reg(&feat_csdev->regs_csdev[i]); + } dev_dbg(&feat_csdev->csdev->dev, "Feature %s: %s", feat_csdev->feat_desc->name, "set on enable"); return 0; @@ -88,13 +87,12 @@ static int cscfg_set_on_enable(struct cscfg_feature_csdev *feat_csdev) /* copy back values from the driver locations referenced in cscfg_reg_csdev */ static void cscfg_save_on_disable(struct cscfg_feature_csdev *feat_csdev) { - unsigned long flags; int i;
- raw_spin_lock_irqsave(feat_csdev->drv_spinlock, flags); - for (i = 0; i < feat_csdev->nr_regs; i++) - cscfg_save_reg(&feat_csdev->regs_csdev[i]); - raw_spin_unlock_irqrestore(feat_csdev->drv_spinlock, flags); + scoped_guard(feat_csdev_lock, feat_csdev) { + for (i = 0; i < feat_csdev->nr_regs; i++) + cscfg_save_reg(&feat_csdev->regs_csdev[i]); + } dev_dbg(&feat_csdev->csdev->dev, "Feature %s: %s", feat_csdev->feat_desc->name, "save on disable"); } diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h index 90fd937d3bd8..ae6295e30813 100644 --- a/drivers/hwtracing/coresight/coresight-config.h +++ b/drivers/hwtracing/coresight/coresight-config.h @@ -7,6 +7,7 @@ #ifndef _CORESIGHT_CORESIGHT_CONFIG_H #define _CORESIGHT_CORESIGHT_CONFIG_H
+#include <linux/cleanup.h> #include <linux/coresight.h> #include <linux/types.h>
@@ -259,4 +260,25 @@ void cscfg_csdev_disable_config(struct cscfg_config_csdev *config_csdev); /* reset a feature to default values */ void cscfg_reset_feat(struct cscfg_feature_csdev *feat_csdev);
+#define feat_csdev_lock(feat_csdev, flags) \ + do { \ + raw_spinlock_t *__lock = feat_csdev->drv_spinlock; \ + typecheck(unsigned long, flags); \ + if (__lock) \ + raw_spin_lock_irqsave(__lock, flags); \ + } while (0) + +#define feat_csdev_unlock(feat_csdev, flags) \ + do { \ + raw_spinlock_t *__lock = feat_csdev->drv_spinlock; \ + typecheck(unsigned long, flags); \ + if (__lock) \ + raw_spin_unlock_irqrestore(__lock, flags); \ + } while (0) + +DEFINE_LOCK_GUARD_1(feat_csdev_lock, struct cscfg_feature_csdev, + feat_csdev_lock(_T->lock, _T->flags), + feat_csdev_unlock(_T->lock, _T->flags), + unsigned long flags) + #endif /* _CORESIGHT_CORESIGHT_CONFIG_H */ diff --git a/drivers/hwtracing/coresight/coresight-etm4x-cfg.c b/drivers/hwtracing/coresight/coresight-etm4x-cfg.c index e1a59b434505..a9f6ed47a2f5 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->curr_config; u32 off_mask;
if (((offset >= TRCEVENTCTL0R) && (offset <= TRCVIPCSSCTLR)) || @@ -154,11 +154,14 @@ static int etm4_cfg_load_feature(struct coresight_device *csdev, int i = 0, err = 0;
/* - * essential we set the device spinlock - this is used in the generic - * programming routines when copying values into the drvdata structures - * via the pointers setup in etm4_cfg_map_reg_offset(). + * drvdata structure of etm4 for configfs is curr_config and + * this curr_config is protected with csdev->mode by restricting + * access to curr_config after mode changed to PERF or SYSFS. + * + * Therefore, it doesn't need to protected with etmv4_drvdata->spinlock + * to feature applying and set the NULL. */ - feat_csdev->drv_spinlock = &drvdata->spinlock; + feat_csdev->drv_spinlock = NULL;
/* process the register descriptions */ for (i = 0; i < feat_csdev->nr_regs && !err; i++) { diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 9ca03a5913a3..61e9971bdc6b 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -264,10 +264,11 @@ 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->curr_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; @@ -275,7 +276,7 @@ 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->curr_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 @@ -286,12 +287,13 @@ 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->curr_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); @@ -299,7 +301,7 @@ 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); @@ -492,7 +494,7 @@ static int etm4_enable_trace_unit(struct etmv4_drvdata *drvdata) static int etm4_enable_hw(struct etmv4_drvdata *drvdata) { int i, rc; - struct etmv4_config *config = &drvdata->config; + struct etmv4_config *config = &drvdata->curr_config; struct coresight_device *csdev = drvdata->csdev; struct device *etm_dev = &csdev->dev; struct csdev_access *csa = &csdev->access; @@ -612,27 +614,42 @@ 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; - if (!coresight_take_mode(csdev, CS_MODE_SYSFS)) { - /* Someone is already using the tracer */ - arg->rc = -EBUSY; - return; + drvdata = arg->drvdata; + csdev = drvdata->csdev; + + /* 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) + return; }
- arg->rc = etm4_enable_hw(arg->drvdata); + drvdata->trcid = arg->path->trace_id; + + /* Tracer will never be paused in sysfs mode */ + drvdata->paused = false;
- /* The tracer didn't start */ + arg->rc = etm4_enable_hw(drvdata); if (arg->rc) { - coresight_set_mode(csdev, CS_MODE_DISABLED); + cscfg_csdev_disable_active_config(csdev); return; }
+ drvdata->sticky_enable = true; csdev->path = arg->path; + + return; }
/* @@ -669,7 +686,7 @@ static int etm4_config_timestamp_event(struct etmv4_drvdata *drvdata, { int ctridx; int rselector; - struct etmv4_config *config = &drvdata->config; + struct etmv4_config *config = &drvdata->curr_config;
/* No point in trying if we don't have at least one counter */ if (!drvdata->nr_cntr) @@ -752,7 +769,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev, { int ret = 0; struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); - struct etmv4_config *config = &drvdata->config; + struct etmv4_config *config = &drvdata->curr_config; struct perf_event_attr max_timestamp = { .ATTR_CFG_FLD_timestamp_CFG = U64_MAX, }; @@ -919,46 +936,36 @@ 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; + int ret;
- /* 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; - } + if (!coresight_take_mode(csdev, CS_MODE_SYSFS)) { + /* Someone is already using the tracer */ + return -EBUSY; }
- 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.path = path; + + scoped_guard(raw_spinlock, &drvdata->spinlock) { + drvdata->curr_config = drvdata->config; + } + 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) + if (!ret) { + dev_dbg(&csdev->dev, "ETM tracing enabled\n"); + } else { etm4_release_trace_id(drvdata); + /* The tracer didn't start */ + coresight_set_mode(csdev, CS_MODE_DISABLED); + }
- raw_spin_unlock(&drvdata->spinlock); - - if (!ret) - dev_dbg(&csdev->dev, "ETM tracing enabled\n"); return ret; }
@@ -1044,7 +1051,7 @@ static void etm4_disable_trace_unit(struct etmv4_drvdata *drvdata) static void etm4_disable_hw(struct etmv4_drvdata *drvdata) { u32 control; - struct etmv4_config *config = &drvdata->config; + struct etmv4_config *config = &drvdata->curr_config; struct coresight_device *csdev = drvdata->csdev; struct csdev_access *csa = &csdev->access; int i; @@ -1090,8 +1097,9 @@ 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); }
static int etm4_disable_perf(struct coresight_device *csdev, @@ -1134,8 +1142,9 @@ static int etm4_disable_perf(struct coresight_device *csdev, static void etm4_disable_sysfs(struct coresight_device *csdev) { struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); - - raw_spin_lock(&drvdata->spinlock); + struct etmv4_config *config = &drvdata->config; + const struct etmv4_config *curr_config = &drvdata->curr_config; + int i;
/* * Executing etm4_disable_hw on the cpu whose ETM is being disabled @@ -1144,9 +1153,19 @@ 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); + /* + * Userspace may read ss_status and cntr_val through sysfs after + * the sysfs-session has been disabled. + */ + for (i = 0; i < drvdata->nr_ss_cmp; i++) + config->ss_status[i] = curr_config->ss_status[i];
- cscfg_csdev_disable_active_config(csdev); + for (i = 0; i < drvdata->nr_cntr; i++) + config->cntr_val[i] = curr_config->cntr_val[i]; + + config->seq_state = curr_config->seq_state; + + coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED);
/* * we only release trace IDs when resetting sysfs. @@ -1694,7 +1713,7 @@ 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->curr_config;
/* * nr_addr_cmp holds the number of comparator _pair_, so time 2 @@ -1735,7 +1754,7 @@ 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->curr_config; struct etm_filters *filters = event->hw.addr_filters;
if (!filters) diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c index bf4e81bc1e8b..ddbcd525613e 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c @@ -1435,7 +1435,8 @@ static ssize_t seq_state_store(struct device *dev,
if (kstrtoul(buf, 16, &val)) return -EINVAL; - if (IS_ERR_OR_NULL(drvdata) || coresight_get_mode(drvdata->csdev)) + if (IS_ERR_OR_NULL(drvdata) || + coresight_get_mode(drvdata->csdev) == CS_MODE_SYSFS) return -EBUSY; if (val >= drvdata->nrseqstate) return -EINVAL; @@ -1616,7 +1617,7 @@ static ssize_t cntr_val_store(struct device *dev, if (val > ETM_CNTR_MAX_VAL) return -EINVAL; if (IS_ERR_OR_NULL(drvdata->csdev) || - coresight_get_mode(drvdata->csdev)) + coresight_get_mode(drvdata->csdev) == CS_MODE_SYSFS) return -EBUSY;
raw_spin_lock(&drvdata->spinlock); diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h index df9e0748d71e..52f66e26ceaa 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.h +++ b/drivers/hwtracing/coresight/coresight-etm4x.h @@ -1019,7 +1019,8 @@ 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. - * @config: structure holding configuration parameters. + * @curr_config: structure holding current applied configuration. + * @config: structure holding sysfs mode configuration. * @save_state: State to be preserved across power loss * @skip_power_up: Indicates if an implementation can skip powering up * the trace unit. @@ -1077,6 +1078,7 @@ struct etmv4_drvdata { bool skip_power_up : 1; bool paused : 1; u64 trfcr; + struct etmv4_config curr_config; struct etmv4_config config; struct etmv4_save_state *save_state; DECLARE_BITMAP(arch_features, ETM4_IMPDEF_FEATURE_MAX);