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 EFB80CF31B5 for ; Wed, 19 Nov 2025 12:24:02 +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=j5DssKvkDvGumTbcAHw6X+oCbvrxsRaBjnkxgXJF7zo=; b=cqYbkkzJS5bqJOfOcNuQlPpuVz ZGHrdzLUmaa6inepvMbPG1pIIUsgVe8i1Mu/H1yOQXb4xFBtsdqk6Vh2Ajg2HDsqunHnYDBG4smHa wR58VwhkwAWISIPj/H0rPFjgW+lqEztYF04ewVLefNVly+nfqXLU/Y5PQq3gJQcdn442QgoOu6gIN cPd8AyZnFDz5IXuIx21lYDp2IV2O9UGN4a0k/n6HXTnzKDSnopaTgmSudg1iRkxMntGKPMmyxuVat UwFYjt7y8bpYhbxcQKeLcTYH9/Yw3nAREnDrNUvIkx5n8k3Gvl80ePva4WqAjZPIxH6LG49gkqzBi 8zneBklg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vLhE1-000000036oy-0qfi; Wed, 19 Nov 2025 12:23:53 +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 1vLhDy-000000036nB-1qL5 for linux-arm-kernel@lists.infradead.org; Wed, 19 Nov 2025 12:23:51 +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 6EBAA1758; Wed, 19 Nov 2025 04:23:42 -0800 (PST) Received: from e134344.cambridge.arm.com (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id CC5933F740; Wed, 19 Nov 2025 04:23:44 -0800 (PST) From: Ben Horgan To: james.morse@arm.com Cc: amitsinght@marvell.com, baisheng.gao@unisoc.com, baolin.wang@linux.alibaba.com, bobo.shaobowang@huawei.com, carl@os.amperecomputing.com, catalin.marinas@arm.com, dakr@kernel.org, dave.martin@arm.com, david@redhat.com, dfustini@baylibre.com, fenghuay@nvidia.com, gregkh@linuxfoundation.org, gshan@redhat.com, guohanjun@huawei.com, jeremy.linton@arm.com, jonathan.cameron@huawei.com, kobak@nvidia.com, lcherian@marvell.com, lenb@kernel.org, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, lpieralisi@kernel.org, peternewman@google.com, quic_jiles@quicinc.com, rafael@kernel.org, robh@kernel.org, rohit.mathew@arm.com, scott@os.amperecomputing.com, sdonthineni@nvidia.com, sudeep.holla@arm.com, tan.shaopeng@fujitsu.com, will@kernel.org, xhao@linux.alibaba.com, reinette.chatre@intel.com, Ben Horgan , Shaopeng Tan , Zeng Heng Subject: [PATCH v6 04/34] ACPI / PPTT: Find cache level by cache-id Date: Wed, 19 Nov 2025 12:22:34 +0000 Message-ID: <20251119122305.302149-5-ben.horgan@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251119122305.302149-1-ben.horgan@arm.com> References: <20251119122305.302149-1-ben.horgan@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-20251119_042350_574594_287062A1 X-CRM114-Status: GOOD ( 18.59 ) 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 From: James Morse The MPAM table identifies caches by id. The MPAM driver also wants to know the cache level to determine if the platform is of the shape that can be managed via resctrl. Cacheinfo has this information, but only for CPUs that are online. Waiting for all CPUs to come online is a problem for platforms where CPUs are brought online late by user-space. Add a helper that walks every possible cache, until it finds the one identified by cache-id, then return the level. Signed-off-by: James Morse Signed-off-by: Ben Horgan Reviewed-by: Gavin Shan Reviewed-by: Fenghua Yu Reviewed-by: Shaopeng Tan Reviewed-by: Jonathan Cameron Tested-by: Fenghua Yu Tested-by: Shaopeng Tan Tested-by: Carl Worth Tested-by: Gavin Shan Tested-by: Zeng Heng Tested-by: Hanjun Guo --- Changes since v4: Initialise acpi_cpu_id at declaration Convert a for loop to do/while (Jonathan) Use new version of acpi_pptt_cache_v1_full Changes since v3: Tags dropped due to rework Fallout/simplification from adding acpi_pptt_cache_v1_full Look for each cache type before incrementing level --- drivers/acpi/pptt.c | 66 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/acpi.h | 5 ++++ 2 files changed, 71 insertions(+) diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c index ef39b176dc00..da49b56a1ef2 100644 --- a/drivers/acpi/pptt.c +++ b/drivers/acpi/pptt.c @@ -932,3 +932,69 @@ void acpi_pptt_get_cpus_from_container(u32 acpi_cpu_id, cpumask_t *cpus) entry->length); } } + +/** + * find_acpi_cache_level_from_id() - Get the level of the specified cache + * @cache_id: The id field of the cache + * + * Determine the level relative to any CPU for the cache identified by + * cache_id. This allows the property to be found even if the CPUs are offline. + * + * The returned level can be used to group caches that are peers. + * + * The PPTT table must be rev 3 or later. + * + * If one CPU's L2 is shared with another CPU as L3, this function will return + * an unpredictable value. + * + * Return: -ENOENT if the PPTT doesn't exist, the revision isn't supported or + * the cache cannot be found. + * Otherwise returns a value which represents the level of the specified cache. + */ +int find_acpi_cache_level_from_id(u32 cache_id) +{ + int cpu; + struct acpi_table_header *table; + + table = acpi_get_pptt(); + if (!table) + return -ENOENT; + + if (table->revision < 3) + return -ENOENT; + + for_each_possible_cpu(cpu) { + bool empty; + int level = 1; + u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu); + struct acpi_pptt_cache *cache; + struct acpi_pptt_processor *cpu_node; + + cpu_node = acpi_find_processor_node(table, acpi_cpu_id); + if (!cpu_node) + continue; + + do { + int cache_type[] = {CACHE_TYPE_INST, CACHE_TYPE_DATA, CACHE_TYPE_UNIFIED}; + + empty = true; + for (int i = 0; i < ARRAY_SIZE(cache_type); i++) { + struct acpi_pptt_cache_v1_full *cache_v1; + + cache = acpi_find_cache_node(table, acpi_cpu_id, cache_type[i], + level, &cpu_node); + if (!cache) + continue; + + empty = false; + + cache_v1 = upgrade_pptt_cache(cache); + if (cache_v1 && cache_v1->cache_id == cache_id) + return level; + } + level++; + } while (!empty); + } + + return -ENOENT; +} diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 4752ebd48132..be074bdfd4d1 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -1542,6 +1542,7 @@ int find_acpi_cpu_topology_cluster(unsigned int cpu); int find_acpi_cpu_topology_package(unsigned int cpu); int find_acpi_cpu_topology_hetero_id(unsigned int cpu); void acpi_pptt_get_cpus_from_container(u32 acpi_cpu_id, cpumask_t *cpus); +int find_acpi_cache_level_from_id(u32 cache_id); #else static inline int acpi_pptt_cpu_is_thread(unsigned int cpu) { @@ -1565,6 +1566,10 @@ static inline int find_acpi_cpu_topology_hetero_id(unsigned int cpu) } static inline void acpi_pptt_get_cpus_from_container(u32 acpi_cpu_id, cpumask_t *cpus) { } +static inline int find_acpi_cache_level_from_id(u32 cache_id) +{ + return -ENOENT; +} #endif void acpi_arch_init(void); -- 2.43.0