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Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH 1/6] ARM: spectre-bhb: enable for Cortex-A15 Content-Language: en-US To: Ard Biesheuvel Cc: "Russell King (Oracle)" , linux-arm-kernel@lists.infradead.org, arnd@arndb.de, linus.walleij@linaro.org, "linux-tegra@vger.kernel.org" References: <20220328134714.205342-1-ardb@kernel.org> <20220328134714.205342-2-ardb@kernel.org> <061d892d-7a16-774a-4b50-b09055040ae2@nvidia.com> From: Jon Hunter In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: LO4P265CA0017.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:2ad::15) To CO6PR12MB5444.namprd12.prod.outlook.com (2603:10b6:5:35e::8) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 57d8fdbd-0470-41f6-12e0-08da4892f66a X-MS-TrafficTypeDiagnostic: MN2PR12MB2973:EE_ X-Microsoft-Antispam-PRVS: X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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So fix that. >>>>> >>>>> Signed-off-by: Ard Biesheuvel >>>>> --- >>>>> arch/arm/mm/proc-v7-bugs.c | 1 + >>>>> 1 file changed, 1 insertion(+) >>>>> >>>>> diff --git a/arch/arm/mm/proc-v7-bugs.c b/arch/arm/mm/proc-v7-bugs.c >>>>> index 06dbfb968182..fb9f3eb6bf48 100644 >>>>> --- a/arch/arm/mm/proc-v7-bugs.c >>>>> +++ b/arch/arm/mm/proc-v7-bugs.c >>>>> @@ -288,6 +288,7 @@ void cpu_v7_ca15_ibe(void) >>>>> { >>>>> if (check_spectre_auxcr(this_cpu_ptr(&spectre_warned), BIT(0))) >>>>> cpu_v7_spectre_v2_init(); >>>>> + cpu_v7_spectre_bhb_init(); >>>>> } >>>>> void cpu_v7_bugs_init(void) >>>> >>>> >>>> Since this patch has been merged, I am seeing a ton of messages when booting >>>> Linux on tegra124-jetson-tk1 ... >>>> >>>> [ 1233.327547] CPU0: Spectre BHB: using loop workaround >>>> [ 1233.327795] CPU1: Spectre BHB: using loop workaround >>>> [ 1233.328270] CPU1: Spectre BHB: using loop workaround >>> >>> Now that you mention this, I vaguely remember some email on the list a >>> while ago about this being caused by something like cpuidle - but I'm >>> unable to find it now. >>> >>>> [0] https://lore.kernel.org/linux-arm-kernel/20220519161310.1489625-1-dmitry.osipenko@collabora.com/T/ >>> >>> That was probably it. >>> >>> We can't really do this for the other print, because the system status >>> can change as a result of CPUs being brought online. :( >>> >> >> Does it make sense to only print the message if/when the method changes >> as opposed to every time the CPUs are brought online? That way, there >> would still be at least one print showing the current method. I believe >> that is what Ard had proposed. >> > > A fix for this issue is already in linux-next: > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=bafa10435c4f34f4b9bda8fc7ee6e4330ebca3ea Ah wonderful! Sorry I had missed that. Once merged can we pull into stable as well? Jon -- nvpublic