From nobody Sun Feb 8 15:58:00 2026 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 2524436CE03; Fri, 17 Oct 2025 18:58:37 +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=1760727518; cv=none; b=uov1eww+e+S91bFsojYjxKH565Xv6n4hadn8stbGqmLTowIH7/kTSSfzu1b6fMgm3KS0+teCaMV7h9V/EMyY24LZYD0CJ+vc2RxJoae7ISES0awOIfxtxaC+5HeOXgqnm0vW5p38irHANTeT32OeAGEWvYkGqXuW1ez57DNblfw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760727518; c=relaxed/simple; bh=ZDnkddHVA67wGKnfxu2HrHojd6o4rL3MbPoUleD7ePY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Xmi60hvUnWsvAuyJQkYgnMzL8SvSHUxQIagD1PQOfAMVW6fBJcHi/4/TM9QHdG5GjN7yvlkp0Mr0/VbLfwoyD4ERfRiPHe9U20lh0l/m8jSiia9qkZq9DIlyOik5jW/WvNgMswRUCLh+rTXZ1CTbeiOJS1c/7XPqXaYClPFGWdQ= 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; 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 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 CC03C1595; Fri, 17 Oct 2025 11:58:28 -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 9C9593F66E; Fri, 17 Oct 2025 11:58:31 -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 , Jeremy Linton , Gavin Shan , Ben Horgan Subject: [PATCH v3 17/29] arm_mpam: Extend reset logic to allow devices to be reset any time Date: Fri, 17 Oct 2025 18:56:33 +0000 Message-Id: <20251017185645.26604-18-james.morse@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20251017185645.26604-1-james.morse@arm.com> References: <20251017185645.26604-1-james.morse@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: quoted-printable Content-Type: text/plain; charset="utf-8" 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 Reviewed-by: Jonathan Cameron Reviewed-by: Ben Horgan Tested-by: Fenghua Yu --- Changes since v2: * Reduced the scop of arguments in mpam_reset_component_locked(). 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 | 58 ++++++++++++++++++++++++++++++++-- 1 file changed, 55 insertions(+), 3 deletions(-) diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index ec089593acad..545482e112b7 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -802,15 +802,13 @@ static void mpam_reset_ris_partid(struct mpam_msc_ris= *ris, u16 partid) =20 /* * Called via smp_call_on_cpu() to prevent migration, while still being - * pre-emptible. + * pre-emptible. Caller must hold mpam_srcu. */ static int mpam_reset_ris(void *arg) { u16 partid, partid_max; struct mpam_msc_ris *ris =3D arg; =20 - WARN_ON_ONCE(!srcu_read_lock_held((&mpam_srcu))); - if (ris->in_reset_state) return 0; =20 @@ -1328,8 +1326,56 @@ static void mpam_enable_once(void) mpam_partid_max + 1, mpam_pmg_max + 1); } =20 +static void mpam_reset_component_locked(struct mpam_component *comp) +{ + + struct mpam_vmsc *vmsc; + + lockdep_assert_cpus_held(); + + guard(srcu)(&mpam_srcu); + list_for_each_entry_srcu(vmsc, &comp->vmsc, comp_list, + srcu_read_lock_held(&mpam_srcu)) { + struct mpam_msc *msc =3D vmsc->msc; + struct mpam_msc_ris *ris; + + 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 =3D 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; =20 mutex_lock(&mpam_cpuhp_state_lock); @@ -1339,6 +1385,12 @@ void mpam_disable(struct work_struct *ignored) } mutex_unlock(&mpam_cpuhp_state_lock); =20 + idx =3D 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); --=20 2.39.5