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 EE0E6CA0FED for ; Wed, 10 Sep 2025 20:45:11 +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: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=I19YAUGE2GxKEj9dpCtbS4Q9If8YZImIeUZMokqxbFQ=; b=DZ7jzE0/JzyjOA0hISOEFWYibD mEU6gdVl5CuuvSzHJxGNGRgXMqEvDsra8C8s1sdTi/p1mROHvap/G74716Y7AQO+zi3/m8AXY/i6R tnkZWtuhgo4JacabQmuF+e0l6A5PIEjfW94efHF3PlnnTZZjDxqLE8/MHDYy0+V3X8JuxIuj/PObA 0CsvanQVNH+Y0HxiU7cKE3j6kC3SatmeQBR5TK4tDnRhHemEmIH8nu4YDyNSwsGa6X1Ueb8+kgnVy ws0YQoz0abhQzYjfKrDlj86fJt75A46N400nLf4MhsWOU0ekjqwDLmonZIDS1PyflptH4UCT6vArt IqyR3hsw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uwRgf-0000000Ge5Q-2REt; Wed, 10 Sep 2025 20:45:05 +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 1uwRgW-0000000Gduf-1Ki0 for linux-arm-kernel@lists.infradead.org; Wed, 10 Sep 2025 20:45:03 +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 760EC22EA; Wed, 10 Sep 2025 13:44:47 -0700 (PDT) Received: from merodach.members.linode.com (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 30FBD3F63F; Wed, 10 Sep 2025 13:44:51 -0700 (PDT) From: James Morse To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org Cc: James Morse , D Scott Phillips OS , carl@os.amperecomputing.com, lcherian@marvell.com, bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com, baolin.wang@linux.alibaba.com, Jamie Iles , Xin Hao , peternewman@google.com, dfustini@baylibre.com, amitsinght@marvell.com, David Hildenbrand , Dave Martin , Koba Ko , Shanker Donthineni , fenghuay@nvidia.com, baisheng.gao@unisoc.com, Jonathan Cameron , Rob Herring , Rohit Mathew , Rafael Wysocki , Len Brown , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Catalin Marinas , Will Deacon , Greg Kroah-Hartman , Danilo Krummrich Subject: [PATCH v2 17/29] arm_mpam: Extend reset logic to allow devices to be reset any time Date: Wed, 10 Sep 2025 20:42:57 +0000 Message-Id: <20250910204309.20751-18-james.morse@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20250910204309.20751-1-james.morse@arm.com> References: <20250910204309.20751-1-james.morse@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-20250910_134456_497390_C9042D86 X-CRM114-Status: GOOD ( 16.35 ) 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 cpuhp callbacks aren't the only time the MSC configuration may need to be reset. Resctrl has an API call to reset a class. If an MPAM error interrupt arrives it indicates the driver has misprogrammed an MSC. The safest thing to do is reset all the MSCs and disable MPAM. Add a helper to reset RIS via their class. Call this from mpam_disable(), which can be scheduled from the error interrupt handler. Signed-off-by: James Morse --- Changes since v1: * more complete use of _srcu helpers. * Use guard macro for srcu. * Dropped a might_sleep() - something else will bark. --- drivers/resctrl/mpam_devices.c | 56 ++++++++++++++++++++++++++++++++-- 1 file changed, 54 insertions(+), 2 deletions(-) diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index e7faf453b5d7..a9d3c4b09976 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -842,8 +842,6 @@ static int mpam_reset_ris(void *arg) u16 partid, partid_max; struct mpam_msc_ris *ris = arg; - mpam_assert_srcu_read_lock_held(); - if (ris->in_reset_state) return 0; @@ -1340,8 +1338,56 @@ static void mpam_enable_once(void) mpam_partid_max + 1, mpam_pmg_max + 1); } +static void mpam_reset_component_locked(struct mpam_component *comp) +{ + struct mpam_msc *msc; + struct mpam_vmsc *vmsc; + struct mpam_msc_ris *ris; + + lockdep_assert_cpus_held(); + + guard(srcu)(&mpam_srcu); + list_for_each_entry_srcu(vmsc, &comp->vmsc, comp_list, + srcu_read_lock_held(&mpam_srcu)) { + msc = vmsc->msc; + + list_for_each_entry_srcu(ris, &vmsc->ris, vmsc_list, + srcu_read_lock_held(&mpam_srcu)) { + if (!ris->in_reset_state) + mpam_touch_msc(msc, mpam_reset_ris, ris); + ris->in_reset_state = true; + } + } +} + +static void mpam_reset_class_locked(struct mpam_class *class) +{ + struct mpam_component *comp; + + lockdep_assert_cpus_held(); + + guard(srcu)(&mpam_srcu); + list_for_each_entry_srcu(comp, &class->components, class_list, + srcu_read_lock_held(&mpam_srcu)) + mpam_reset_component_locked(comp); +} + +static void mpam_reset_class(struct mpam_class *class) +{ + cpus_read_lock(); + mpam_reset_class_locked(class); + cpus_read_unlock(); +} + +/* + * Called in response to an error IRQ. + * All of MPAMs errors indicate a software bug, restore any modified + * controls to their reset values. + */ void mpam_disable(struct work_struct *ignored) { + int idx; + struct mpam_class *class; struct mpam_msc *msc, *tmp; mutex_lock(&mpam_cpuhp_state_lock); @@ -1351,6 +1397,12 @@ void mpam_disable(struct work_struct *ignored) } mutex_unlock(&mpam_cpuhp_state_lock); + idx = srcu_read_lock(&mpam_srcu); + list_for_each_entry_srcu(class, &mpam_classes, classes_list, + srcu_read_lock_held(&mpam_srcu)) + mpam_reset_class(class); + srcu_read_unlock(&mpam_srcu, idx); + mutex_lock(&mpam_list_lock); list_for_each_entry_safe(msc, tmp, &mpam_all_msc, all_msc_list) mpam_msc_destroy(msc); -- 2.39.5