From mboxrd@z Thu Jan 1 00:00:00 1970 From: xieyisheng1@huawei.com (Yisheng Xie) Date: Thu, 18 Jan 2018 16:37:17 +0800 Subject: [PATCH v2 07/11] arm64: Add skeleton to harden the branch predictor against aliasing attacks In-Reply-To: <20180117100715.GA27892@arm.com> References: <1515157961-20963-1-git-send-email-will.deacon@arm.com> <1515157961-20963-8-git-send-email-will.deacon@arm.com> <01c224eb-9bec-6b16-7ecf-14837cc107b6@huawei.com> <20180117100715.GA27892@arm.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Will, On 2018/1/17 18:07, Will Deacon wrote: > On Wed, Jan 17, 2018 at 12:10:33PM +0800, Yisheng Xie wrote: >> 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? > > post_ttbr_update_workaround just runs code after a TTBR update, which > includes mitigations against variant 2 of "spectre" and also a workaround > for a Cavium erratum. These are separate issues. Get it, Thanks for your kind explain. Thanks Yisheng > > Will > > . >