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 7E435CD6E44 for ; Thu, 28 May 2026 14:27:11 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=pFJ/ywYor2WZCvHkqATZq9QUDDlj9d/3ElvsUofMQxU=; b=Hfw3iWtala/P4iaQD4Qljill8y aU9d5nvNnlEEO3bi94V6P5u+qTRJWeFY0xNshDdMvWmUm2id+Xml01X+AAYWjudkRsz1+Oj1qQPKH LxXdpD5+YTB39G+RsgWJyv17OqxCixeR8gjL76i7GAQBlA7MaICXaXogP9Ga6bW6zWEItKrg8XP0l U/XrxEhefjJeXQAYX0BJ3nya4Za55Y2mH+f9dJJdgY5diyBoULhpK7hAwI+3mD0DmIN88ULwG3BzG Fwn45Ns7gvLlC3D8GE1kV+7ZffkvqfjGyw1BrLR8p5YrCom0QUN9MQhKrnvR9SXCwrBQAAuSvgikM O4qdK94A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wSbhR-00000005qbz-0w3k; Thu, 28 May 2026 14:27:05 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wSbhO-00000005qbU-27p0 for linux-arm-kernel@lists.infradead.org; Thu, 28 May 2026 14:27:03 +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 DDCF044A7; Thu, 28 May 2026 07:26:55 -0700 (PDT) Received: from e129823.arm.com (e129823.arm.com [10.1.197.6]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B77A43F905; Thu, 28 May 2026 07:26:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1779978420; bh=s6F2Efxk2WV9Dt67rZc51h8FcFWKXsHu+eFkbXrErJs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qAY5l++byfOwPF2u3LBdI3Vpw6JqqF+VELGxkF674kpeuPxiUrIAbUNXip44z7JIW He0cqJKpU96XY6tTQeLAvDb51AZtfHxigE3YMQBu/k6XqOtLAEjzWrI7WxgLiq7v97 Zht9Muub4O6+O2aNnpmHN8c87ARJhH2iB1p6lFQ4= Date: Thu, 28 May 2026 15:26:57 +0100 From: Yeoreum Yun To: Leo Yan Cc: coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, suzuki.poulose@arm.com, mike.leach@arm.com, james.clark@linaro.org, alexander.shishkin@linux.intel.com, jie.gan@oss.qualcomm.com Subject: Re: [PATCH v7 08/13] coresight: etm4x: fix inconsistencies with sysfs configuration Message-ID: References: <20260519154812.254884-1-yeoreum.yun@arm.com> <20260519154812.254884-9-yeoreum.yun@arm.com> <20260528140943.GE101133@e132581.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260528140943.GE101133@e132581.arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260528_072702_630383_3686ED0F X-CRM114-Status: GOOD ( 39.80 ) 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 Hi Leo, > On Tue, May 19, 2026 at 04:48:07PM +0100, Yeoreum Yun wrote: > > [...] > > > --- 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; > > Wouldn't it make more sense to keep using drvdata->config for cfgfs? > This would avoid cfgfs updating the active configuration while a session > is enabled. > > My understanding is after refactoring cfgfs, we will never expose > active_config or config anymore so this should not an issue. Before > that, maybe we just keep to use config so can avoid mess. I don't think so. since the cfgfs's config is updated right before enable and in this patchset, It's applied after "take the mode". If we do it into drvdta->config, then contention would be increased with the access of sysfs and that nullifies almost this patch purpose and because of we use "one config" this makes a corruption with perf and sysfs. Therefore, It might be right to remain this as it is. and let's remove it at the time of refactorying. > > > 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; > > Can move this down to just before drvdata->trcid assignment so cscfg > operations can be put together? No. Copy the arg->config must be before cscfg_csdev_enable_active_config(). If that's after, it overrides the "preset" and this is different from the former behavior. > > > + > > + 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; > > Add a new goto tag (like err_enable_hw) for the disable_active_config > rollback? This is only place where cscfg_csdev_disable_active_config(). Why do we need to goto for cleanup where there is no duplication? > > > } > > > > + 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); > > Move cscfg_csdev_disable_active_config() just after etm4_disable_hw() so > the sequence is consistent with perf mode. Fair enough. I'll do that. > > [...] > > > @@ -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; > > config->s_ex_level is redundant and not really a configuration item. > We should use caps->s_ex_level instead of config->s_ex_level wherever > it is used. Agree, but this includes it should change the omse function declations to pass "caps" argument: - etm4_set_comparator_filter() - etm4_set_start_stop_filter() If that's okay, I'll respin with it. > > Thanks, > Leo -- Sincerely, Yeoreum Yun