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 34ADAC83F1A for ; Fri, 11 Jul 2025 18:45:10 +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=RggpFjZcK0iSnEkBOLQk6M0bGUJF8RIrVvdd0TZfH+U=; b=SGUH7UDkAUSsgsOtnXFdQ716+q F9yBKWBiwYn7GOMD6V0qrJ2umzIwVMW46FeIhEQdQK4UQvuZI+Hgjz5q2gQdmD3vKnHlOBJhA/BTB pM7Sov7SsRL/P7rkKuC1Xeofirwwcgqon6C8n/0WuJkN3vXTUnHggR7gxtheeymplt1EQ9k3HaHJX Yel9Oi6Lc1BB4jFfpMWO1T8m2FsqLiFC5HjtRLaDYiBnOi6ooaeV6KX6QCbH/f5q8QUxsbuFEHl87 NtQKD/Z7qtMEKusJ/w2GSFYShzKNvLjWKFilTAHXQJdMPjqqMEepDIHKNz9cGcCc+Tjopcz01D3Hc HUUqBLvw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uaIk4-0000000FYvA-0AWF; Fri, 11 Jul 2025 18:45:04 +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 1uaIcN-0000000FX2Z-193q for linux-arm-kernel@lists.infradead.org; Fri, 11 Jul 2025 18:37:08 +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 2B6D016F8; Fri, 11 Jul 2025 11:36:56 -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 4C1963F694; Fri, 11 Jul 2025 11:37:03 -0700 (PDT) From: James Morse To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Rob Herring , Ben Horgan , Rohit Mathew , Shanker Donthineni , Zeng Heng , Lecopzer Chen , Carl Worth , shameerali.kolothum.thodi@huawei.com, D Scott Phillips OS , 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 , Greg Kroah-Hartman , "Rafael J. Wysocki" , James Morse , Jonathan Cameron , Gavin Shan Subject: [RFC PATCH 01/36] cacheinfo: Set cache 'id' based on DT data Date: Fri, 11 Jul 2025 18:36:13 +0000 Message-Id: <20250711183648.30766-2-james.morse@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20250711183648.30766-1-james.morse@arm.com> References: <20250711183648.30766-1-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-20250711_113707_391960_82EF9FCB X-CRM114-Status: GOOD ( 17.42 ) 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: Rob Herring Use the minimum CPU h/w id of the CPUs associated with the cache for the cache 'id'. This will provide a stable id value for a given system. As we need to check all possible CPUs, we can't use the shared_cpu_map which is just online CPUs. As there's not a cache to CPUs mapping in DT, we have to walk all CPU nodes and then walk cache levels. The cache_id exposed to user-space has historically been 32 bits, and is too late to change. This value is parsed into a u32 by user-space libraries such as libvirt: https://github.com/libvirt/libvirt/blob/master/src/util/virresctrl.c#L1588 Give up on assigning cache-id's if a CPU h/w id greater than 32 bits is found. match_cache_node() does not make use of the __free() cleanup helpers because of_find_next_cache_node(prev) does not drop a reference to prev, and its too easy to accidentally drop the reference on cpu, which belongs to for_each_of_cpu_node(). Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Signed-off-by: Rob Herring [ ben: converted to use the __free cleanup idiom ] Signed-off-by: Ben Horgan [ morse: Add checks to give up if a value larger than 32 bits is seen. ] Signed-off-by: James Morse Reviewed-by: Jonathan Cameron Reviewed-by: Gavin Shan --- Use as a 32bit value has also been seen in DPDK patches here: http://inbox.dpdk.org/dev/20241021015246.304431-2-wathsala.vithanage@arm.com/ Changes since v2: * Removed broken use of cleanup in the match helper Changes since v1: * Remove the second loop in favour of a helper. --- drivers/base/cacheinfo.c | 45 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c index cf0d455209d7..4e2f60c85e74 100644 --- a/drivers/base/cacheinfo.c +++ b/drivers/base/cacheinfo.c @@ -8,6 +8,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include +#include #include #include #include @@ -183,6 +184,49 @@ static bool cache_node_is_unified(struct cacheinfo *this_leaf, return of_property_read_bool(np, "cache-unified"); } +static bool match_cache_node(struct device_node *cpu, + const struct device_node *cache_node) +{ + struct device_node *prev, *cache = of_find_next_cache_node(cpu); + + while (cache) { + if (cache == cache_node) { + of_node_put(cache); + return true; + } + + prev = cache; + cache = of_find_next_cache_node(cache); + of_node_put(prev); + } + + return false; +} + +static void cache_of_set_id(struct cacheinfo *this_leaf, + struct device_node *cache_node) +{ + struct device_node *cpu; + u32 min_id = ~0; + + for_each_of_cpu_node(cpu) { + u64 id = of_get_cpu_hwid(cpu, 0); + + if (FIELD_GET(GENMASK_ULL(63, 32), id)) { + of_node_put(cpu); + return; + } + + if (match_cache_node(cpu, cache_node)) + min_id = min(min_id, id); + } + + if (min_id != ~0) { + this_leaf->id = min_id; + this_leaf->attributes |= CACHE_ID; + } +} + static void cache_of_set_props(struct cacheinfo *this_leaf, struct device_node *np) { @@ -198,6 +242,7 @@ static void cache_of_set_props(struct cacheinfo *this_leaf, cache_get_line_size(this_leaf, np); cache_nr_sets(this_leaf, np); cache_associativity(this_leaf); + cache_of_set_id(this_leaf, np); } static int cache_setup_of_node(unsigned int cpu) -- 2.39.5