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 4211AC43458 for ; Thu, 9 Jul 2026 07:36:23 +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: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=nameEV+0DQA14P65XZurQsDCAJ5p3N3TEbqhk7lxywc=; b=23KgORmzEqzqGx2oFHp6MWDat5 v/9uekVE+oGAd8d8NQ67YbkZzkYv3M3Q6rq+UcVm4ofmuN6xtYcvbtdKIHdgYqVkYjESX42HwU5FQ oZC9OdZo9uiEl/nwTwhFTUEZmGTafYmIA/U2kwEFMh7LoSaNEJrFegzB+KdXK8S7MQ05MzQUx6caS jXICrxEN/br0laAOMNbTEv+Bqa20pcwlnVEF+JB4dhl9JgS6Ck+Wdam5nqF8dA8g64qppySmyIimS ddZTtreUV0oozJ+AOuO0FrPZNqKxyOIiKKVLzLAxg3aqgA7mlIB0SHGjkfLho7kRyGOd7UQo959+3 B8VyAU7g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1whjIu-00000001Jbi-3uYT; Thu, 09 Jul 2026 07:36:16 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1whjIt-00000001Jaq-1qvC for linux-arm-kernel@lists.infradead.org; Thu, 09 Jul 2026 07:36:16 +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 471E315A1; Thu, 9 Jul 2026 00:36:10 -0700 (PDT) Received: from [10.41.150.148] (e142021.arm.com [10.41.150.148]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D28073F66F; Thu, 9 Jul 2026 00:36:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1783582574; bh=8sfhycHbh/KxK1a8FZ4v3kkfMX38FffCMj8F1aGLOrE=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=UDmSLeWYCQ6eENgHGLBq2RT///VUSQA3jbHG4hIoVpBhilDuNu9yxytLHkYVSiUeK xzRnXQLJOZp0AjABSNX3qkHZdwNhvHcebz0x47o0LDS/uIlVL9VMzZ4x1e4AEaqVGV d9aj4bfQuRhm32Ixu++/v04/unD8kdPQ87UnG0/E= Message-ID: Date: Thu, 9 Jul 2026 09:36:09 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 04/15] arm_mpam: propagate MSC read errors for mpam_msc_read_mbwu_l() To: Ben Horgan , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Catalin Marinas , Will Deacon , "Rafael J . Wysocki" , Len Brown , James Morse , Reinette Chatre , Fenghua Yu Cc: Jonathan Cameron , Srivathsa L Rao , Ganapatrao Kulkarni , Trilok Soni , Srinivas Ramana , Niyas Sait , linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20260702162229.4008659-1-andre.przywara@arm.com> <20260702162229.4008659-5-andre.przywara@arm.com> <717a2f77-7caa-4cf5-acd5-c2f86686e34e@arm.com> Content-Language: en-GB From: Andre Przywara In-Reply-To: <717a2f77-7caa-4cf5-acd5-c2f86686e34e@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260709_003615_585258_64B84E8D X-CRM114-Status: GOOD ( 15.51 ) 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 Hi Ben, On 7/1/26 22:06, Ben Horgan wrote: > Hi Andre, > > On 7/2/26 17:22, Andre Przywara wrote: >> Allow the mpam_msc_read_mbwu_l() function to return an error, and >> propagate read errors from the lower level up. >> >> Signed-off-by: Andre Przywara >> --- >> drivers/resctrl/mpam_devices.c | 13 ++++++++++--- >> 1 file changed, 10 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c >> index 011d1e3544d7..1d06902fb970 100644 >> --- a/drivers/resctrl/mpam_devices.c >> +++ b/drivers/resctrl/mpam_devices.c >> @@ -1106,6 +1106,7 @@ static bool mpam_ris_has_mbwu_long_counter(struct mpam_msc_ris *ris) >> >> static u64 mpam_msc_read_mbwu_l(struct mpam_msc *msc) > > Now that your changing the other helpers to return an error and pass a > pointer to hold the register value it would seem more consistent for > this call to follow the same pattern. Ah, I wasn't entirely sure whether this MSMON___L_NRDY is just some error flag (abuse), since NRDY is some kind of architecture feature. If that's indeed here the case, I will be changing the prototype and adjust the function. Cheers, Andre > Thanks, > > Ben > >> { >> + int ret; >> int retry = 3; >> u32 mbwu_l_low; >> u32 mbwu_l_high1, mbwu_l_high2; >> @@ -1115,11 +1116,17 @@ static u64 mpam_msc_read_mbwu_l(struct mpam_msc *msc) >> WARN_ON_ONCE((MSMON_MBWU_L + sizeof(u64)) > msc->mapped_hwpage_sz); >> WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &msc->accessibility)); >> >> - __mpam_read_reg(msc, MSMON_MBWU_L + 4, &mbwu_l_high2); >> + ret = __mpam_read_reg(msc, MSMON_MBWU_L + 4, &mbwu_l_high2); >> + if (ret) >> + return MSMON___L_NRDY; >> + >> do { >> mbwu_l_high1 = mbwu_l_high2; >> - __mpam_read_reg(msc, MSMON_MBWU_L, &mbwu_l_low); >> - __mpam_read_reg(msc, MSMON_MBWU_L + 4, &mbwu_l_high2); >> + ret = __mpam_read_reg(msc, MSMON_MBWU_L, &mbwu_l_low); >> + if (!ret) >> + ret = __mpam_read_reg(msc, MSMON_MBWU_L + 4, &mbwu_l_high2); >> + if (ret) >> + return MSMON___L_NRDY; >> >> retry--; >> } while (mbwu_l_high1 != mbwu_l_high2 && retry > 0); >