From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 4015E4657E0 for ; Fri, 18 Sep 2026 17:00:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789750829; cv=none; b=A6saQiGZSPCNjo6bkfx10Yzi/8gqnDeevegrMaXEpq2j8PPIamYiDX7Fzfq7QnOUJ089mwjQ+Jx3Ce86yVrrf1h5pR4kTIH92VNp9C0N/2ZUbFGSbB233ys7mxgxZpFBIo19tVho0kUrR9KHhTLLjt4BTpNaJaPVIuYXO8is3Pw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789750829; c=relaxed/simple; bh=+HEjUYFWTGLYxr8PX6lAWu1BSI8JsmZfOErx/Ka5hNw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lhGhd5BMTjMMxVZ52JE5QHO5FF6tuj2/9FWTf74yYo6rKqzboDZZvcihB1CpNHk2Y15Zvy3uSrcWiWuaMrOyzgyngBGoX34q10pgNlFSQpSHskEl5sYHbYXJDi5uw9Iv57i6sIeYozHLXWuFQoTmKe8s6kOzFaRSyyui5sVW2wM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=cqzxrFB5; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="cqzxrFB5" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1C7711476; Fri, 18 Sep 2026 10:00:21 -0700 (PDT) Received: from e129823.arm.com (e129823.arm.com [10.2.213.3]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8A7203F86C; Fri, 18 Sep 2026 10:00:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1789750824; bh=+HEjUYFWTGLYxr8PX6lAWu1BSI8JsmZfOErx/Ka5hNw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cqzxrFB5qn/UMV+YaBf8m1wQslh3F2mqCMM0KUL0ZeuTtNog0UvyqR5XfAVN0AXq0 POQ2tTPOQ+fqjmocNdXRlFEcXlHT/MPwhLy3arI9NFwDe39d7XHbaBOt2f+rqPFRbr u8K0gpoo67xg3cqAD02Ez823oQUTcxpyjiEEk4JQ= Date: Fri, 18 Sep 2026 18:00:20 +0100 From: Yeoreum Yun To: Mike Leach Cc: Yeoreum Yun , James Clark , Leo Yan , Greg Kroah-Hartman , Mathieu Poirier , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, Suzuki K Poulose , Alexander Shishkin , Sebastian Andrzej Siewior , Clark Williams , Steven Rostedt , nd@arm.com Subject: Re: [PATCH v11 3/9] coresight: etm4x: fix inconsistencies with sysfs configuration Message-ID: References: <20260915-separate_etm_cfg_v2-v11-0-d2b258d51747@arm.com> <20260915-separate_etm_cfg_v2-v11-3-d2b258d51747@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Sep 18, 2026 at 02:49:09PM +0100, Mike Leach wrote: > Hi, > > On 9/15/26 12:34, Yeoreum Yun wrote: > > 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 > > > > I'll add a comment about naming here - active_config is a bit overloaded in > the code as it is also used by the csconfig code to represent a loaded and > active configuration - which may at some point be applied to the > active_config above. > > If active_config is for the current session then curr_config would work. > > Additionally config also appears as a local pointer in many of the > functions. If this is the sysfs config then sysfs_config would work better. > > This should make all the code a lot more readable, and easier to spot > exactly which config we are dealing with. Okay. then I'll change the each name with curr_config and sysfs_config and rename all. Thanks ;) > > > > 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. > > > > As the active_config is used for cfg-configfs, etmv4 doesn't need to set > > its lock for the cfg-configfs since the active_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") > > Signed-off-by: Yeoreum Yun > > --- > > 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 | 118 ++++++++++++--------- > > .../hwtracing/coresight/coresight-etm4x-sysfs.c | 6 +- > > drivers/hwtracing/coresight/coresight-etm4x.h | 4 +- > > 6 files changed, 113 insertions(+), 68 deletions(-) > > > > diff --git a/drivers/hwtracing/coresight/coresight-config.c b/drivers/hwtracing/coresight/coresight-config.c > > index 4f72ae71b696e..0e296289f286d 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 90fd937d3bd83..ae6295e308131 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 > > #include > > #include > > @@ -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 e1a59b4345052..d24f533c623d0 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)) || > > @@ -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 active_config and > > + * this active_config is protected with csdev->mode by restricting > > + * access to active_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 2247ad55d4442..2df7f592bb5cf 100644 > > --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c > > +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c > > @@ -239,6 +239,7 @@ 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; > > drvdata contains both active_config and config - why the extra copy here? This is because of a minor consistency before applying the configuration to hardware. Since drvdata->sysfs_config could be modified while copying the contents into the active_config as a purpose of snapshot at the time of enable, add this argument. For example, while enabling, sysfs could modify the ctxid_mask0 and ctxid_mask1 and this could be teared when active_config is copied from drvdata->config directly. Therefore, make a config as a *snapshot* while holding a drvdata->lock. otherwise, we need to change all spinlock usage in sysfs should be irqsave but it seems much awful. But I think we can remove it if we move the copy config to active_config into etm4_enable_sysfs() since there, sysfs_mode is taken. so active_config could be accessed safely. I'll move the drvdata->active_config = drvdata->config into etm4_enable_sysfs() and will remove this arg. Thanks! > > > int rc; > > }; > > @@ -264,10 +265,11 @@ 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; > > @@ -275,7 +277,7 @@ 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 > > @@ -286,12 +288,13 @@ 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); > > @@ -299,7 +302,7 @@ 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 +495,7 @@ 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->active_config; > > struct coresight_device *csdev = drvdata->csdev; > > struct device *etm_dev = &csdev->dev; > > struct csdev_access *csa = &csdev->access; > > @@ -612,27 +615,44 @@ 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; > > + > > + drvdata->active_config = arg->config; > > This can happen before the smp call removing the need for arg->config? Yes! That's fair enough :) > > > + > > + /* 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; > > - /* The tracer didn't start */ > > + /* 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); > > + cscfg_csdev_disable_active_config(csdev); > > return; > > } > > + drvdata->sticky_enable = true; > > csdev->path = arg->path; > > + > > + return; > > } > > /* > > @@ -669,7 +689,7 @@ 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->active_config; > > /* No point in trying if we don't have at least one counter */ > > if (!drvdata->nr_cntr) > > @@ -752,7 +772,7 @@ 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->active_config; > > struct perf_event_attr max_timestamp = { > > .ATTR_CFG_FLD_timestamp_CFG = U64_MAX, > > }; > > @@ -919,46 +939,36 @@ 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) { > > + arg.config = drvdata->config; > > Given as mentioned above that once a mode is set then active_config is > protected, this should simply be drvdata->active_config = drvdata->config; > ?? Right. Here is much better! > > > + } > > + > > 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 +1054,7 @@ 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->active_config; > > struct coresight_device *csdev = drvdata->csdev; > > struct csdev_access *csa = &csdev->access; > > int i; > > @@ -1086,8 +1096,9 @@ 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, > > @@ -1130,8 +1141,9 @@ 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 *active_config = &drvdata->active_config; > > + int i; > > /* > > * Executing etm4_disable_hw on the cpu whose ETM is being disabled > > @@ -1140,9 +1152,17 @@ 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] = active_config->ss_status[i]; > > - cscfg_csdev_disable_active_config(csdev); > > + for (i = 0; i < drvdata->nr_cntr; i++) > > + config->cntr_val[i] = active_config->cntr_val[i]; > > + > > Readback of TRCSEQSTR needed here too. Right. I've noticted after I post this patch. I'll fix in the next version. Thanks! > > > + coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED); > > /* > > * we only release trace IDs when resetting sysfs. > > @@ -1690,7 +1710,7 @@ 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 > > @@ -1731,7 +1751,7 @@ 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) > > diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c > > index 8d73248b840a6..f64c0acebc701 100644 > > --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c > > +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c > > @@ -1613,7 +1613,7 @@ static ssize_t cntr_val_store(struct device *dev, > > return -EINVAL; > > if (val > ETM_CNTR_MAX_VAL) > > return -EINVAL; > > - if (coresight_get_mode(drvdata->csdev)) > > + if (coresight_get_mode(drvdata->csdev) == CS_MODE_SYSFS) > > return -EBUSY; > > raw_spin_lock(&drvdata->spinlock); > > @@ -1799,7 +1799,7 @@ static ssize_t sshot_ctrl_store(struct device *dev, > > if (kstrtoul(buf, 16, &val)) > > return -EINVAL; > > - if (coresight_get_mode(drvdata->csdev)) > > + if (coresight_get_mode(drvdata->csdev) == CS_MODE_SYSFS) > > return -EBUSY; > > raw_spin_lock(&drvdata->spinlock); > > @@ -1851,7 +1851,7 @@ static ssize_t sshot_pe_ctrl_store(struct device *dev, > > if (kstrtoul(buf, 16, &val)) > > return -EINVAL; > > - if (coresight_get_mode(drvdata->csdev)) > > + if (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 df9e0748d71ec..c33700711154d 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. > > + * @active_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 active_config; > > struct etmv4_config config; > > struct etmv4_save_state *save_state; > > DECLARE_BITMAP(arch_features, ETM4_IMPDEF_FEATURE_MAX); > > > > Regards > > Mike Thanks! -- Sincerely, Yeoreum Yun