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 C96EE31DDA4; Fri, 19 Sep 2025 16:11:06 +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=1758298268; cv=none; b=Rt82toR/ekKnVkwXd8ElEjb0OLGiLiXMSWw2o6IIxW62+Io7BE3hmW9qY7EYSEIVUitc8aO5ZU9oplb0GZIW7RsPXGetcBWYiz5UxfNAyJIrfIF3Y5cN2hqBX0Cl8cKM8GldNPh+sBazWBAGvNhdKBnqJ8xbLy/SPQlHNHdPG68= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758298268; c=relaxed/simple; bh=ldrrKQvGttJzr+6AlPlEkwsAbBzrUGjgSum6lf1cfbs=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ZAku6E2vW8p5irAoIhQC5JksgJqEsDDqv7fzXqPpVAW+P9Au3RFhsNCY9mHRNi95evttXss8SfmALDVXY83HjLaFWYnfK7alQJc3DDGTX+r3jmrhkksnz0GN0Bo99bjFQGIuBxScN4Q1k6Qf0QcCwI/mwPCnaVS5KcJb6PcmxDk= 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 C261F1D14; Fri, 19 Sep 2025 09:10:57 -0700 (PDT) Received: from [10.1.197.69] (eglon.cambridge.arm.com [10.1.197.69]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B1E143F66E; Fri, 19 Sep 2025 09:11:00 -0700 (PDT) Message-ID: <7fe33c0b-affb-4e30-a3fd-24e4c2013654@arm.com> Date: Fri, 19 Sep 2025 17:10:57 +0100 Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 04/29] ACPI / PPTT: Add a helper to fill a cpumask from a cache_id To: Jonathan Cameron Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, 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, Rob Herring , Rohit Mathew , Rafael Wysocki , Len Brown , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Catalin Marinas , Will Deacon , Greg Kroah-Hartman , Danilo Krummrich References: <20250910204309.20751-1-james.morse@arm.com> <20250910204309.20751-5-james.morse@arm.com> <20250911120614.00001e92@huawei.com> Content-Language: en-GB From: James Morse In-Reply-To: <20250911120614.00001e92@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Jonathan, On 11/09/2025 12:06, Jonathan Cameron wrote: > On Wed, 10 Sep 2025 20:42:44 +0000 > 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. > Why for this case does it makes sense to not just use acpi_get_pptt()? > > Also you don't introduce the acpi_get_table_reg() helper until patch 6. I missed fixing this one up. That's done now. >> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c >> index c5f2a51d280b..c379a9952b00 100644 >> --- a/drivers/acpi/pptt.c >> +++ b/drivers/acpi/pptt.c >> @@ -966,3 +966,62 @@ 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 unified cache > > Similar comment to previous patch. If we are going to make this unified only > can we reflect that in the function name. I worry this will get reused > and that restriction will surprise. I agree - the unified restriction turns out only to be of interest to archaeologists. I've ripped it out. >> + * @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) >> +{ >> + u32 acpi_cpu_id; >> + int level, cpu, num_levels; >> + struct acpi_pptt_cache *cache; >> + struct acpi_pptt_cache_v1 *cache_v1; >> + struct acpi_pptt_processor *cpu_node; >> + struct acpi_table_header *table __free(acpi_table) = acpi_get_table_ret(ACPI_SIG_PPTT, 0); >> + >> + cpumask_clear(cpus); >> + >> + if (IS_ERR(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 (WARN_ON_ONCE(!cpu_node)) >> + continue; I'm not sure why this one is a WARN_ON_ONCE() and the other isn't - both mean the PPTT table is missing CPUs, but this looks like leftover debug. I'll drop it. >> + num_levels = acpi_count_levels(table, cpu_node, NULL); >> + >> + /* Start at 1 for L1 */ >> + for (level = 1; level <= num_levels; level++) { >> + cache = acpi_find_cache_node(table, acpi_cpu_id, >> + ACPI_PPTT_CACHE_TYPE_UNIFIED, >> + level, &cpu_node); >> + if (!cache) >> + continue; >> + >> + cache_v1 = ACPI_ADD_PTR(struct acpi_pptt_cache_v1, >> + cache, >> + sizeof(struct acpi_pptt_cache)); > > sizeof(*cache) makes more sense to me. Yup, I've done that in the previous one It's not otherwise done in this file - lets see if someone cares strongly the other way. >> + >> + if (cache->flags & ACPI_PPTT_CACHE_ID_VALID && >> + cache_v1->cache_id == cache_id) >> + cpumask_set_cpu(cpu, cpus); >> + } >> + } >> + >> + return 0; >> +} Thanks, James