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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6C0FBC10F27 for ; Wed, 11 Mar 2020 09:26:37 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3AA9820828 for ; Wed, 11 Mar 2020 09:26:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3AA9820828 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=chris-wilson.co.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E95006E94D; Wed, 11 Mar 2020 09:26:36 +0000 (UTC) Received: from fireflyinternet.com (mail.fireflyinternet.com [109.228.58.192]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6D0446E94D for ; Wed, 11 Mar 2020 09:26:35 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from build.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 20518591-1500050 for multiple; Wed, 11 Mar 2020 09:26:26 +0000 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Wed, 11 Mar 2020 09:26:22 +0000 Message-Id: <20200311092624.10012-1-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 1/3] drm/i915/gt: Pull checking rps->pm_events under the irq_lock X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Avoid angering kcsan by serialising the read of the pm_events with the write in rps_disable_interrupts. [ 6268.713419] BUG: KCSAN: data-race in intel_rps_park [i915] / rps_work [i915] [ 6268.713437] [ 6268.713449] write to 0xffff8881eda8efac of 4 bytes by task 1127 on cpu 3: [ 6268.713680] intel_rps_park+0x136/0x260 [i915] [ 6268.713905] __gt_park+0x61/0xa0 [i915] [ 6268.714128] ____intel_wakeref_put_last+0x42/0x90 [i915] [ 6268.714352] __intel_wakeref_put_work+0xd3/0xf0 [i915] [ 6268.714369] process_one_work+0x3b1/0x690 [ 6268.714384] worker_thread+0x80/0x670 [ 6268.714398] kthread+0x19a/0x1e0 [ 6268.714412] ret_from_fork+0x1f/0x30 [ 6268.714423] [ 6268.714435] read to 0xffff8881eda8efac of 4 bytes by task 950 on cpu 2: [ 6268.714664] rps_work+0xc2/0x680 [i915] [ 6268.714679] process_one_work+0x3b1/0x690 [ 6268.714693] worker_thread+0x80/0x670 [ 6268.714707] kthread+0x19a/0x1e0 [ 6268.714720] ret_from_fork+0x1f/0x30 v2: Mark all reads and writes of rpm->pm_events. The flow of enabling/disabling rps is stronly ordered, so the writes and interrupt generation are also strongly ordered -- just this may not be visible to the compiler, so provide annotations. Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/gt/intel_rps.c | 29 +++++++++++++++++------------ 1 file changed, 17 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c index 1b1cda2438d1..87f9638d2cbf 100644 --- a/drivers/gpu/drm/i915/gt/intel_rps.c +++ b/drivers/gpu/drm/i915/gt/intel_rps.c @@ -57,7 +57,7 @@ static u32 rps_pm_mask(struct intel_rps *rps, u8 val) if (val < rps->max_freq_softlimit) mask |= GEN6_PM_RP_UP_EI_EXPIRED | GEN6_PM_RP_UP_THRESHOLD; - mask &= rps->pm_events; + mask &= READ_ONCE(rps->pm_events); return rps_pm_sanitize_mask(rps, ~mask); } @@ -70,17 +70,19 @@ static void rps_reset_ei(struct intel_rps *rps) static void rps_enable_interrupts(struct intel_rps *rps) { struct intel_gt *gt = rps_to_gt(rps); + u32 events; rps_reset_ei(rps); if (IS_VALLEYVIEW(gt->i915)) /* WaGsvRC0ResidencyMethod:vlv */ - rps->pm_events = GEN6_PM_RP_UP_EI_EXPIRED; + events = GEN6_PM_RP_UP_EI_EXPIRED; else - rps->pm_events = (GEN6_PM_RP_UP_THRESHOLD | - GEN6_PM_RP_DOWN_THRESHOLD | - GEN6_PM_RP_DOWN_TIMEOUT); + events = (GEN6_PM_RP_UP_THRESHOLD | + GEN6_PM_RP_DOWN_THRESHOLD | + GEN6_PM_RP_DOWN_TIMEOUT); + WRITE_ONCE(rps->pm_events, events); spin_lock_irq(>->irq_lock); gen6_gt_pm_enable_irq(gt, rps->pm_events); spin_unlock_irq(>->irq_lock); @@ -117,8 +119,7 @@ static void rps_disable_interrupts(struct intel_rps *rps) { struct intel_gt *gt = rps_to_gt(rps); - rps->pm_events = 0; - + WRITE_ONCE(rps->pm_events, 0); set(gt->uncore, GEN6_PMINTRMSK, rps_pm_sanitize_mask(rps, ~0u)); spin_lock_irq(>->irq_lock); @@ -1459,12 +1460,12 @@ static void rps_work(struct work_struct *work) u32 pm_iir = 0; spin_lock_irq(>->irq_lock); - pm_iir = fetch_and_zero(&rps->pm_iir); + pm_iir = fetch_and_zero(&rps->pm_iir) & READ_ONCE(rps->pm_events); client_boost = atomic_read(&rps->num_waiters); spin_unlock_irq(>->irq_lock); /* Make sure we didn't queue anything we're not going to process. */ - if ((pm_iir & rps->pm_events) == 0 && !client_boost) + if (!pm_iir && !client_boost) goto out; mutex_lock(&rps->lock); @@ -1560,11 +1561,15 @@ void gen11_rps_irq_handler(struct intel_rps *rps, u32 pm_iir) void gen6_rps_irq_handler(struct intel_rps *rps, u32 pm_iir) { struct intel_gt *gt = rps_to_gt(rps); + u32 events; - if (pm_iir & rps->pm_events) { + events = pm_iir & READ_ONCE(rps->pm_events); + if (events) { spin_lock(>->irq_lock); - gen6_gt_pm_mask_irq(gt, pm_iir & rps->pm_events); - rps->pm_iir |= pm_iir & rps->pm_events; + + gen6_gt_pm_mask_irq(gt, events); + rps->pm_iir |= events; + schedule_work(&rps->work); spin_unlock(>->irq_lock); } -- 2.20.1 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx