Subject: Re: [PATCH v2 07/11] arm64: Add skeleton to harden the branch
 predictor against aliasing attacks
To: Will Deacon <will.deacon@arm.com>,
        <linux-arm-kernel@lists.infradead.org>
References: <1515157961-20963-1-git-send-email-will.deacon@arm.com>
 <1515157961-20963-8-git-send-email-will.deacon@arm.com>
CC: <catalin.marinas@arm.com>, <ard.biesheuvel@linaro.org>,
        <marc.zyngier@arm.com>, <lorenzo.pieralisi@arm.com>,
        <christoffer.dall@linaro.org>, <linux-kernel@vger.kernel.org>,
        <labbott@redhat.com>
From: Yisheng Xie <xieyisheng1@huawei.com>
Message-ID: <01c224eb-9bec-6b16-7ecf-14837cc107b6@huawei.com>
Date: Wed, 17 Jan 2018 12:10:33 +0800
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Hi Will,

On 2018/1/5 21:12, Will Deacon wrote:
> diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c
> index 5f7097d0cd12..d99b36555a16 100644
> --- a/arch/arm64/mm/context.c
> +++ b/arch/arm64/mm/context.c
> @@ -246,6 +246,8 @@ asmlinkage void post_ttbr_update_workaround(void)
>  			"ic iallu; dsb nsh; isb",
>  			ARM64_WORKAROUND_CAVIUM_27456,
>  			CONFIG_CAVIUM_ERRATUM_27456));
> +
> +	arm64_apply_bp_hardening();
>  }

post_ttbr_update_workaround was used for fix Cavium erratum 2745? so does that
means, if we do not have this erratum, we do not need arm64_apply_bp_hardening()?
when mm_swtich and kernel_exit?

>From the code logical, it seems not only related to erratum 2745 anymore?
should it be renamed?

Thanks
Yisheng