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 001C0625; Mon, 20 Oct 2025 10:45:39 +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=1760957141; cv=none; b=kNPVXAJXvTr0ui3ud0/da0C7YG3YhOYG3VuCZFqTTZlFKY/xdLfqmK0owIvzXdg0OYJoOA/CAdzxreBdjD9rvF8nrPHZU+We7u+pGxC0gbL4xI4LAp4HIrG2xwBLfHPzfao5kv9oE3njakYX33DkeGd09EKf5kjNDU0z3Kvb9b8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760957141; c=relaxed/simple; bh=5m9H2gZKzdHPUG97NZYPx0g4bz72wHoii/cqiqml9Gg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=mqnGLCyoCcETFR8Q9Nzio0nkwFZQjk0wIxG8nAh0y8CKKdsrJjAwweOBF0Q2e/nAOMNZzo5esME5wqZX2SrTIVJkwzKwyJg7CjuXwRJ+PBlhnvNsgnH8XkOp7MHHs4Mh2f6TuP4gEuewGkoFSDlJ02jNjlWYrti3IUIC7js5t8o= 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 6A8081063; Mon, 20 Oct 2025 03:45:31 -0700 (PDT) Received: from [10.1.196.46] (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B92943F63F; Mon, 20 Oct 2025 03:45:34 -0700 (PDT) Message-ID: <12556653-a26f-4c28-820a-4b5ba1537bc4@arm.com> Date: Mon, 20 Oct 2025 11:45:33 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 04/29] ACPI / PPTT: Add a helper to fill a cpumask from a cache_id To: James Morse , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org Cc: 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 References: <20251017185645.26604-1-james.morse@arm.com> <20251017185645.26604-5-james.morse@arm.com> From: Ben Horgan Content-Language: en-US In-Reply-To: <20251017185645.26604-5-james.morse@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi James, On 10/17/25 19:56, James Morse wrote: > MPAM identifies CPUs by the cache_id in the PPTT cache structure. > > The driver needs to know which CPUs are associated with the cache. > The CPUs may not all be online, so cacheinfo does not have the > information. > > Add a helper to pull this information out of the PPTT. > > CC: Rohit Mathew > Signed-off-by: James Morse > Reviewed-by: Sudeep Holla > Tested-by: Fenghua Yu > --- > Changes since v2: > * Removed stray cleanup useage in preference for acpi_get_pptt(). > * Removed WARN_ON_ONCE() for symmetry with other helpers. > * Dropped restriction on unified caches. > > Changes since v1: > * Added punctuation to the commit message. > * Removed a comment about an alternative implementaion. > * Made the loop continue with a warning if a CPU is missing from the PPTT. > > Changes since RFC: > * acpi_count_levels() now returns a value. > * Converted the table-get stuff to use Jonathan's cleanup helper. > * Dropped Sudeep's Review tag due to the cleanup change. > --- > drivers/acpi/pptt.c | 64 ++++++++++++++++++++++++++++++++++++++++++++ > include/linux/acpi.h | 6 +++++ > 2 files changed, 70 insertions(+) > > diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c > index 50c8f2a3c927..2f86f58699a6 100644 > --- a/drivers/acpi/pptt.c > +++ b/drivers/acpi/pptt.c > @@ -985,3 +985,67 @@ int find_acpi_cache_level_from_id(u32 cache_id) > > return -ENOENT; > } > + > +/** > + * acpi_pptt_get_cpumask_from_cache_id() - Get the cpus associated with the > + * specified cache > + * @cache_id: The id field of the cache > + * @cpus: Where to build the cpumask > + * > + * Determine which CPUs are below this cache in the PPTT. This allows the property > + * to be found even if the CPUs are offline. > + * > + * The PPTT table must be rev 3 or later, > + * > + * Return: -ENOENT if the PPTT doesn't exist, or the cache cannot be found. > + * Otherwise returns 0 and sets the cpus in the provided cpumask. > + */ > +int acpi_pptt_get_cpumask_from_cache_id(u32 cache_id, cpumask_t *cpus) > +{ > + int level, cpu; > + u32 acpi_cpu_id; > + struct acpi_pptt_cache *cache; > + struct acpi_table_header *table; > + struct acpi_pptt_cache_v1 *cache_v1; > + struct acpi_pptt_processor *cpu_node; > + > + cpumask_clear(cpus); > + > + table = acpi_get_pptt(); > + if (!table) > + return -ENOENT; > + > + if (table->revision < 3) > + return -ENOENT; > + > + for_each_possible_cpu(cpu) { > + acpi_cpu_id = get_acpi_id_for_cpu(cpu); > + cpu_node = acpi_find_processor_node(table, acpi_cpu_id); > + if (!cpu_node) > + continue; > + > + /* Start at 1 for L1 */ > + level = 1; > + cache = acpi_find_any_type_cache_node(table, acpi_cpu_id, level, > + &cpu_node); > + while (cache) { > + cache_v1 = ACPI_ADD_PTR(struct acpi_pptt_cache_v1, > + cache, sizeof(*cache)); > + if (!cache) > + continue; > + > + cache_v1 = ACPI_ADD_PTR(struct acpi_pptt_cache_v1, > + cache, sizeof(*cache)); > + > + if (cache->flags & ACPI_PPTT_CACHE_ID_VALID && > + cache_v1->cache_id == cache_id) > + cpumask_set_cpu(cpu, cpus); > + > + level++; Same comment as for the previous patch. You are bumping the level without considering if there is another cache at that level. > + cache = acpi_find_any_type_cache_node(table, acpi_cpu_id, > + level, &cpu_node); > + } > + } > + > + return 0; > +} Thanks, Ben