From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751400AbeAWPHa (ORCPT ); Tue, 23 Jan 2018 10:07:30 -0500 Received: from foss.arm.com ([217.140.101.70]:42980 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751056AbeAWPH3 (ORCPT ); Tue, 23 Jan 2018 10:07:29 -0500 Subject: Re: [PATCH 02/16] arm64: Move errata work around check on boot CPU To: Dave Martin Cc: linux-arm-kernel@lists.infradead.org, mark.rutland@arm.com, ckadabi@codeaurora.org, ard.biesheuvel@linaro.org, marc.zyngier@arm.com, catalin.marinas@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, jnair@caviumnetworks.com References: <20180123122809.16269-1-suzuki.poulose@arm.com> <20180123122809.16269-3-suzuki.poulose@arm.com> <20180123145934.GS22781@e103592.cambridge.arm.com> From: Suzuki K Poulose Message-ID: <31e6c173-9c27-80fd-a24e-8d234bb4be01@arm.com> Date: Tue, 23 Jan 2018 15:07:18 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <20180123145934.GS22781@e103592.cambridge.arm.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23/01/18 14:59, Dave Martin wrote: > On Tue, Jan 23, 2018 at 12:27:55PM +0000, Suzuki K Poulose wrote: >> We trigger CPU errata work around check on the boot CPU from >> smp_prepare_boot_cpu() to make sure that we run the checks only >> after the CPU feature infrastructure is initialised. > > On the surface of it, this sounds like a bug fix. No, this is not. It is just moving the code to cpufeature.c Earlier it was : smp_prepare_boot_cpu() -> cpuinfo_store_boot_cpu() -> init_cpu_features() and then we did update_cpu_errata_workarounds() after we have done cpuinfo_store_boot_cpu(). With this change we do : smp_prepare_boot_cpu() -> cpuinfo_store_boot_cpu() -> init_cpu_features() -> update_cpu_errata_workarounds() > > Should there be a Fixes tag if so? > > If this reordering doesn't matter for upstream, it would be good to have > a quick explanation here as to why not. Sure, will make it clearer. Cheers Suzuki > > Cheers > ---Dave > >> >> We can do this from init_cpu_features() which is called only >> on the boot CPU and does the initilisation of the infrastructure. >> As we are consolidating the cpu capability handling, let us >> move this to where it should belong. No functional changes. >> >> Signed-off-by: Suzuki K Poulose >> --- >> arch/arm64/kernel/cpufeature.c | 6 ++++++ >> arch/arm64/kernel/smp.c | 6 ------ >> 2 files changed, 6 insertions(+), 6 deletions(-) >> >> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c >> index 6a8dfdc532b1..ebb467340b9c 100644 >> --- a/arch/arm64/kernel/cpufeature.c >> +++ b/arch/arm64/kernel/cpufeature.c >> @@ -545,6 +545,12 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info) >> init_cpu_ftr_reg(SYS_ZCR_EL1, info->reg_zcr); >> sve_init_vq_map(); >> } >> + >> + /* >> + * Run the errata work around checks on the boot CPU, once we have >> + * initialised the cpu feature infrastructure. >> + */ >> + update_cpu_errata_workarounds(); >> } >> >> static void update_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 new) >> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c >> index 3b8ad7be9c33..5cef11450183 100644 >> --- a/arch/arm64/kernel/smp.c >> +++ b/arch/arm64/kernel/smp.c >> @@ -448,12 +448,6 @@ void __init smp_prepare_boot_cpu(void) >> jump_label_init(); >> cpuinfo_store_boot_cpu(); >> save_boot_cpu_run_el(); >> - /* >> - * Run the errata work around checks on the boot CPU, once we have >> - * initialised the cpu feature infrastructure from >> - * cpuinfo_store_boot_cpu() above. >> - */ >> - update_cpu_errata_workarounds(); >> } >> >> static u64 __init of_get_cpu_mpidr(struct device_node *dn) >> -- >> 2.13.6 >> >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel