From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A915B23D297; Fri, 22 Aug 2025 15:33:16 +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=1755876798; cv=none; b=rQqjER8DMRC0idYFTzmW/Tlh1NTw4cnvOJY4gFN/g0FrgF9stJ2l+DMiSWoCOLzklAcF/vAaBESccSFx10DOOGJk9+UprjaTBu/ahdeusr62EUvSQm00kCpx4I+MeMXPDa/xT+bZWQ+E+yujOAA1m13ttApP21CPq3kjbxNlbss= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755876798; c=relaxed/simple; bh=TihBLORAFE4lrQMsSm4i/TF11ZiZA36p7IhI3+Wg0d4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=s78uapkgkxjo4s6+QNq7N+5ynHJmvTX+yt2g/1JTNwjvrP2bu2kgMO0S0pSPBQfSkx2CGjzrRVl+LqFmyG9O7+WBqxxuK7HAdh+AiAkUTmH1rUH4UNCRvkjswVcRgW7LelgK1cvI4HiTItOuGpWw12tIVJkYaMfOHPxYJHns3og= 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 E083427DC; Fri, 22 Aug 2025 08:33:07 -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 D58263F63F; Fri, 22 Aug 2025 08:33:10 -0700 (PDT) From: James Morse To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, devicetree@vger.kernel.org Cc: James Morse , shameerali.kolothum.thodi@huawei.com, 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 , Rex Nie , 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 , Krzysztof Kozlowski , Conor Dooley , Catalin Marinas , Will Deacon , Greg Kroah-Hartman , Danilo Krummrich Subject: [PATCH 23/33] arm_mpam: Use a static key to indicate when mpam is enabled Date: Fri, 22 Aug 2025 15:30:04 +0000 Message-Id: <20250822153048.2287-24-james.morse@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20250822153048.2287-1-james.morse@arm.com> References: <20250822153048.2287-1-james.morse@arm.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Once all the MSC have been probed, the system wide usable number of PARTID is known and the configuration arrays can be allocated. After this point, checking all the MSC have been probed is pointless, and the cpuhp callbacks should restore the configuration, instead of just resetting the MSC. Add a static key to enable this behaviour. This will also allow MPAM to be disabled in repsonse to an error, and the architecture code to enable/disable the context switch of the MPAM system registers. Signed-off-by: James Morse --- drivers/resctrl/mpam_devices.c | 8 ++++++++ drivers/resctrl/mpam_internal.h | 8 ++++++++ 2 files changed, 16 insertions(+) diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index 210d64fad0b1..b424af666b1e 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -33,6 +33,8 @@ #include "mpam_internal.h" +DEFINE_STATIC_KEY_FALSE(mpam_enabled); /* TODO: move to arch code */ + /* * mpam_list_lock protects the SRCU lists when writing. Once the * mpam_enabled key is enabled these lists are read-only, @@ -1039,6 +1041,9 @@ static int mpam_discovery_cpu_online(unsigned int cpu) struct mpam_msc *msc; bool new_device_probed = false; + if (mpam_is_enabled()) + return 0; + mutex_lock(&mpam_list_lock); list_for_each_entry(msc, &mpam_all_msc, glbl_list) { if (!cpumask_test_cpu(cpu, &msc->accessibility)) @@ -1835,6 +1840,7 @@ static void mpam_enable_once(void) return; } + static_branch_enable(&mpam_enabled); mpam_register_cpuhp_callbacks(mpam_cpu_online, mpam_cpu_offline); printk(KERN_INFO "MPAM enabled with %u partid and %u pmg\n", @@ -1902,6 +1908,8 @@ static irqreturn_t mpam_disable_thread(int irq, void *dev_id) } mutex_unlock(&mpam_cpuhp_state_lock); + static_branch_disable(&mpam_enabled); + mpam_unregister_irqs(); idx = srcu_read_lock(&mpam_srcu); diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h index c9418c9cf9f2..3476ee97f8ac 100644 --- a/drivers/resctrl/mpam_internal.h +++ b/drivers/resctrl/mpam_internal.h @@ -8,6 +8,7 @@ #include #include #include +#include #include #include #include @@ -15,6 +16,13 @@ #include #include +DECLARE_STATIC_KEY_FALSE(mpam_enabled); + +static inline bool mpam_is_enabled(void) +{ + return static_branch_likely(&mpam_enabled); +} + /* * Structures protected by SRCU may not be freed for a surprising amount of * time (especially if perf is running). To ensure the MPAM error interrupt can -- 2.20.1