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 31AC8230278 for ; Mon, 14 Jul 2025 11:40:13 +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=1752493217; cv=none; b=Nes+iqJGGlK+ojTiwy3dFYT67ntZfPYFvvbm8C8UGhKksIMR6oVn6RGccT3QJUopIz3DmC811huZhV/suRnKz3n/zcfUntAEyK5kschIRhmIREJHtCzBlH4AJ8Y1MMlzHMs9T2N3SEYfxRsJlTaphO8H1TbnY5lpzg14cVPNGv4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752493217; c=relaxed/simple; bh=sgpiVqFhfBlwkMB09h5GPNBzjQ5ubf8tm+IVrkeGXK4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Ygi5rVvujeOAnfTn9aDsJbmlBDvTBflDgilPkb6zjpuuurKrCLAIiOAok9ouaY9oj+qB+IHs1YH/EicJKsBHJUnYi4FN80NKRmXD2wlxfiMEPwqV7i42E5+v1tcJBp7r4KjPHei0HIDqPbNjkafibk2DYddIBSWSYE4AutK98gY= 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 190571BC0; Mon, 14 Jul 2025 04:40:04 -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 20B393F694; Mon, 14 Jul 2025 04:40:10 -0700 (PDT) Message-ID: Date: Mon, 14 Jul 2025 12:40:08 +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: [RFC PATCH 04/36] cacheinfo: Expose the code to generate a cache-id from a device_node To: James Morse , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Rob Herring , 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 References: <20250711183648.30766-1-james.morse@arm.com> <20250711183648.30766-5-james.morse@arm.com> Content-Language: en-US From: Ben Horgan In-Reply-To: <20250711183648.30766-5-james.morse@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi James, On 7/11/25 19:36, James Morse wrote: > The MPAM driver identifies caches by id for use with resctrl. It > needs to know the cache-id when probe-ing, but the value isn't set > in cacheinfo until device_initcall(). > > Expose the code that generates the cache-id. The parts of the MPAM > driver that run early can use this to set up the resctrl structures > before cacheinfo is ready in device_initcall(). > > Signed-off-by: James Morse > --- > Changes since v1: > * Renamed cache_of_get_id() cache_of_calculate_id(). > --- > drivers/base/cacheinfo.c | 17 ++++++++++++----- > include/linux/cacheinfo.h | 1 + > 2 files changed, 13 insertions(+), 5 deletions(-) > > diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c > index 613410705a47..0fdd6358ee73 100644 > --- a/drivers/base/cacheinfo.c > +++ b/drivers/base/cacheinfo.c > @@ -207,8 +207,7 @@ static bool match_cache_node(struct device_node *cpu, > #define arch_compact_of_hwid(_x) (_x) > #endif > > -static void cache_of_set_id(struct cacheinfo *this_leaf, > - struct device_node *cache_node) > +unsigned long cache_of_calculate_id(struct device_node *cache_node) > { > struct device_node *cpu; > u32 min_id = ~0; > @@ -219,15 +218,23 @@ static void cache_of_set_id(struct cacheinfo *this_leaf, > id = arch_compact_of_hwid(id); > if (FIELD_GET(GENMASK_ULL(63, 32), id)) { > of_node_put(cpu); > - return; > + return ~0UL; > } > > if (match_cache_node(cpu, cache_node)) > min_id = min(min_id, id); > } > > - if (min_id != ~0) { > - this_leaf->id = min_id; > + return min_id; Looks like some 32bit/64bit confusion. Don't we want to return ~0UL if min_id == ~0? > +} > + > +static void cache_of_set_id(struct cacheinfo *this_leaf, > + struct device_node *cache_node) > +{ > + unsigned long id = cache_of_calculate_id(cache_node); > + > + if (id != ~0UL) { > + this_leaf->id = id; > this_leaf->attributes |= CACHE_ID; > } > } > diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h > index c8f4f0a0b874..2dcbb69139e9 100644 > --- a/include/linux/cacheinfo.h > +++ b/include/linux/cacheinfo.h > @@ -112,6 +112,7 @@ int acpi_get_cache_info(unsigned int cpu, > #endif > > const struct attribute_group *cache_get_priv_group(struct cacheinfo *this_leaf); > +unsigned long cache_of_calculate_id(struct device_node *np); > > /* > * Get the cacheinfo structure for the cache associated with @cpu at Thanks, Ben