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 BC37E400DE7 for ; Tue, 19 May 2026 15:48:39 +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=1779205722; cv=none; b=lmfzLzrLhdCsSwpYvtGNzMiSwsFsGPgvRDC4QxnW+C0CC+Ulxl3ay1l2SSXavlZLzggF+oqYLbbmi3+haDKOjfHMUMxzTAMPVLO5RO5pfVPnX+utqL8DUXCFlFDEgZ4f28RNI6LU3IzCJWH8JRSthoZ2pat4Sl11xNoc2ddZ/xI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779205722; c=relaxed/simple; bh=j9lJOVGqLHE8ZpNO0t7HoeRl4zeD++yFKR/dTIxVcTU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=BkY7cP/28Fkmk8XAfUBxHglHwhEBQzSVVTGlu+4JAnyWqhs8CBGI3aQdCXCLzXe/zD0OiD6Bz5jKj1Jx8dXQyM/v5BDy2i2Al77sMoEn7cIk2/5uCFscO8WAEJatIWZfNz6g8yluW/vwzWCT6u8b3mJhlFU5VOgBp8vsfTzgH/g= 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=Ic8ycZNY; 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="Ic8ycZNY" 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 98AB41682; Tue, 19 May 2026 08:48:33 -0700 (PDT) Received: from e129823.cambridge.arm.com (e129823.arm.com [10.1.197.6]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 6237D3F632; Tue, 19 May 2026 08:48:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1779205718; bh=j9lJOVGqLHE8ZpNO0t7HoeRl4zeD++yFKR/dTIxVcTU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ic8ycZNYgT1br9Y0ehGBmwrLj5Y9gtG0JdI2GVKHRc7+x+Yp4vFIt/HKXWVhLNtN4 cJdC4iDasPbs8Pn9F5g/gSp3zbXjKMVE6AmTMZ4xxYHoDajJ9tZXPHAKwB53AgebgR v7H5mVngecYiPqHP7TGOdiPo3jHg47Y+KG/z2uNs= From: Yeoreum Yun To: coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: suzuki.poulose@arm.com, mike.leach@arm.com, james.clark@linaro.org, alexander.shishkin@linux.intel.com, leo.yan@arm.com, jie.gan@oss.qualcomm.com, Yeoreum Yun Subject: [PATCH v7 08/13] coresight: etm4x: fix inconsistencies with sysfs configuration Date: Tue, 19 May 2026 16:48:07 +0100 Message-Id: <20260519154812.254884-9-yeoreum.yun@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260519154812.254884-1-yeoreum.yun@arm.com> References: <20260519154812.254884-1-yeoreum.yun@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 --- .../hwtracing/coresight/coresight-etm4x-cfg.c | 2 +- .../coresight/coresight-etm4x-core.c | 107 ++++++++++-------- drivers/hwtracing/coresight/coresight-etm4x.h | 2 + 3 files changed, 61 insertions(+), 50 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 9b477b36b432..f0a9f2ef4b27 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -243,6 +243,7 @@ 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; }; @@ -268,10 +269,11 @@ 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; @@ -279,7 +281,7 @@ 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 @@ -290,12 +292,13 @@ 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); @@ -303,7 +306,7 @@ 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); @@ -497,7 +500,7 @@ 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; @@ -618,27 +621,53 @@ 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); + /* enable any config activated by configfs */ + cscfg_config_sysfs_get_active_cfg(&cfg_hash, &preset); - /* The tracer didn't start */ + drvdata->active_config = arg->config; + + 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); } /* @@ -676,7 +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) @@ -760,7 +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 +951,7 @@ 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 +959,20 @@ 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 +1059,7 @@ 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; @@ -1091,6 +1102,8 @@ static void etm4_disable_sysfs_smp_call(void *info) etm4_disable_hw(drvdata); drvdata->csdev->path = NULL; + cscfg_csdev_disable_active_config(drvdata->csdev); + 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 @@ -1382,6 +1389,7 @@ 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; @@ -1389,6 +1397,7 @@ static void etm4_init_arch_data(void *info) drvdata = dev_get_drvdata(init_arg->dev); caps = &drvdata->caps; csa = init_arg->csa; + config = &drvdata->config; /* * If we are unable to detect the access mechanism, @@ -1449,7 +1458,7 @@ 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); /* @@ -1695,7 +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 @@ -1736,7 +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) diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h index cdeb2140735d..485750b72635 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]; -- LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}