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 7F071CCF9F8 for ; Fri, 7 Nov 2025 12:36:04 +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=hR1Bln2Hw/yvB+/y4kaMTd9sJ0OYsVvNJ/1F+otSyLw=; b=V8RtaoDcQdF/dYxgiZKzcwY+r+ zIliKefh4mxpV2tBaav3oU2RXaCTH1b+/qDfXTZ4RcuX/CM+ZVecm3AszpZMCBOXbBCxBfOR2H3Zs F5D6POhA5pOS9/60tbZzVS/9loTIFwoxcaaA7a0EglxqCkmdqHiGVFRgptv3ixXPuPzjkHIPS4T6I upB00pRbUuCCebKu7ijrnDJmC9qTB72RuyPhygokUr2fq/3Tm6YzavcAWckbgUOPhSAc2RxNuyk2k aIAFex3ef9uPv+7YNkS8slHq+cfDt3rhRRpMQU6VQplcM7wmZf9jzq9yh7YEcRD6nTmyArD6jT0cQ HgbEwpJA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vHLh6-0000000HIpC-1aEk; Fri, 07 Nov 2025 12:35:57 +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 1vHLh1-0000000HImt-0Hhi for linux-arm-kernel@lists.infradead.org; Fri, 07 Nov 2025 12:35:54 +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 5AFFB1515; Fri, 7 Nov 2025 04:35:41 -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 4F81E3F66E; Fri, 7 Nov 2025 04:35:44 -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, Ben Horgan Subject: [PATCH 04/33] ACPI / PPTT: Find cache level by cache-id Date: Fri, 7 Nov 2025 12:34:21 +0000 Message-ID: <20251107123450.664001-5-ben.horgan@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20251107123450.664001-1-ben.horgan@arm.com> References: <20251107123450.664001-1-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-20251107_043551_200416_59E2D720 X-CRM114-Status: GOOD ( 16.97 ) 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 --- 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 | 63 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/acpi.h | 5 ++++ 2 files changed, 68 insertions(+) diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c index 1ed2099c0d1a..71841c106020 100644 --- a/drivers/acpi/pptt.c +++ b/drivers/acpi/pptt.c @@ -918,3 +918,66 @@ 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 not_empty = true; + u32 acpi_cpu_id; + struct acpi_pptt_cache_v1_full *cache; + struct acpi_pptt_processor *cpu_node; + + acpi_cpu_id = get_acpi_id_for_cpu(cpu); + cpu_node = acpi_find_processor_node(table, acpi_cpu_id); + if (!cpu_node) + continue; + + for (int level = 1; not_empty; level++) { + int cache_type[] = {CACHE_TYPE_INST, CACHE_TYPE_DATA, CACHE_TYPE_UNIFIED}; + + not_empty = false; + for (int i = 0; i < ARRAY_SIZE(cache_type); i++) { + cache = acpi_find_cache_node(table, acpi_cpu_id, cache_type[i], + level, &cpu_node); + if (!cache) + continue; + + not_empty = true; + + if (acpi_pptt_cache_id_is_valid(cache) && + cache->extra.cache_id == cache_id) + return level; + } + } + } + + 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