From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7C83FF34C56 for ; Mon, 13 Apr 2026 14:20:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=t7SdMO+wj8+n4a3vRBME+AOgYIpFttVA2gKZDMeUKR8=; b=jdoQDf1ugbI8cfOfo23/RQ/Od7 VScNqsuLVMML/a1RmX8TmU9I/yJDv8/ty+su2UX8NWA11SBsjVn7+0gMxQQk6NLYDNa+bq5NqRIK1 v8T+276f0+xx3a0JAE407EOGizvFh1TSgFbGk74iEn4yWkOjCJuzYC/m0n/PlB09x/NGA3CseIBvD 6hHMTEWALJXq/A0lOV/zh0+SABm0wunAsumDGhpbQZMuw9hQ7+SfhaZ4ZekANmxkJzj7+nPQgqGfU D2UfQHAuxOEPj9l1p/+Kzj51EVL5G/9ny0UW6zLaMmMFTyzq0unCt7e1zvgSRr5pqRX9EE7iBRW0W NAUcZpyA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wCI9C-0000000FqWe-3QUx; Mon, 13 Apr 2026 14:20:18 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wCI9A-0000000FqUi-1jvm for linux-arm-kernel@lists.infradead.org; Mon, 13 Apr 2026 14:20:17 +0000 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 BADC1357A; Mon, 13 Apr 2026 07:20:08 -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 E6C9A3F641; Mon, 13 Apr 2026 07:20:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1776090014; bh=P0w6tAmsC+xLkCfnavSGADQ0U3gIqU9Uy9b/9UUD+/U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UUvTr8elC7Y+5TBO7fFH/gqyS/TCUwNEvF2vsWKbIDdGgGetGHaVMi1McVNCNGpa+ eUOhSzrmvRYrUYgpLOhkT8j1SiBabUdqk5dAEzHHFyHH6cmZQd+VNk2yCbjCP6btt4 YJ2zQYAp0ku5Xv0L4YE/D/4ZofJMfma7NnYLd9sg= 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 v4 4/9] coresight: etm4x: fix inconsistencies with sysfs configuration Date: Mon, 13 Apr 2026 15:19:57 +0100 Message-Id: <20260413142003.3549310-5-yeoreum.yun@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260413142003.3549310-1-yeoreum.yun@arm.com> References: <20260413142003.3549310-1-yeoreum.yun@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260413_072016_540232_EF7DB819 X-CRM114-Status: GOOD ( 27.11 ) 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 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. 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, 62 insertions(+), 49 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; if (((offset >= TRCEVENTCTL0R) && (offset <= TRCVIPCSSCTLR)) || diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c index 1bc9f13e33f7..01099689525b 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c @@ -245,6 +245,10 @@ void etm4_release_trace_id(struct etmv4_drvdata *drvdata) struct etm4_enable_arg { struct etmv4_drvdata *drvdata; + unsigned long cfg_hash; + int preset; + u8 trace_id; + struct etmv4_config config; int rc; }; @@ -270,10 +274,11 @@ 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 +286,7 @@ 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 +297,13 @@ 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 +311,7 @@ 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 +505,7 @@ 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; @@ -616,23 +622,46 @@ 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 = arg->config; - /* The tracer didn't start */ + if (arg->cfg_hash) { + arg->rc = cscfg_csdev_enable_active_config(csdev, + arg->cfg_hash, + arg->preset); + if (arg->rc) + goto err; + } + + drvdata->trcid = arg->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); + goto err; + + drvdata->sticky_enable = true; + + return; +err: + /* The tracer didn't start */ + etm4_release_trace_id(drvdata); + coresight_set_mode(csdev, CS_MODE_DISABLED); } /* @@ -670,7 +699,7 @@ 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 +783,7 @@ 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, }; @@ -916,38 +945,24 @@ 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) { - 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; /* * 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; + + 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) - etm4_release_trace_id(drvdata); - - raw_spin_unlock(&drvdata->spinlock); - if (!ret) dev_dbg(&csdev->dev, "ETM tracing enabled\n"); return ret; @@ -1036,7 +1051,7 @@ 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; @@ -1072,6 +1087,8 @@ 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); } @@ -1122,7 +1139,6 @@ static void etm4_disable_sysfs(struct coresight_device *csdev) * DYING hotplug callback is serviced by the ETM driver. */ cpus_read_lock(); - raw_spin_lock(&drvdata->spinlock); /* * Executing etm4_disable_hw on the cpu whose ETM is being disabled @@ -1131,10 +1147,6 @@ 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); - cpus_read_unlock(); /* @@ -1377,6 +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; @@ -1384,6 +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->active_config; /* * If we are unable to detect the access mechanism, @@ -1444,7 +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); /* @@ -1689,7 +1703,7 @@ 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 @@ -1730,7 +1744,7 @@ 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) @@ -1848,13 +1862,11 @@ static int etm4_starting_cpu(unsigned int cpu) if (!etmdrvdata[cpu]) return 0; - raw_spin_lock(&etmdrvdata[cpu]->spinlock); if (!etmdrvdata[cpu]->os_unlock) etm4_os_unlock(etmdrvdata[cpu]); if (coresight_get_mode(etmdrvdata[cpu]->csdev)) etm4_enable_hw(etmdrvdata[cpu]); - raw_spin_unlock(&etmdrvdata[cpu]->spinlock); return 0; } @@ -1863,10 +1875,8 @@ static int etm4_dying_cpu(unsigned int cpu) if (!etmdrvdata[cpu]) return 0; - raw_spin_lock(&etmdrvdata[cpu]->spinlock); if (coresight_get_mode(etmdrvdata[cpu]->csdev)) etm4_disable_hw(etmdrvdata[cpu]); - raw_spin_unlock(&etmdrvdata[cpu]->spinlock); return 0; } @@ -2252,7 +2262,8 @@ 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 8864cfb76bad..725e6360a8b9 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.h +++ b/drivers/hwtracing/coresight/coresight-etm4x.h @@ -1071,6 +1071,7 @@ 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. @@ -1091,6 +1092,7 @@ 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); -- LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}