Messages in this thread | | | Date | Fri, 05 Jan 2018 14:46:37 +0000 | From | James Morse <> | Subject | Re: [PATCH v2 11/11] arm64: Implement branch predictor hardening for affected Cortex-A CPUs |
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Hi Marc, Will,
(SOB-chain suggests a missing From: tag on this and patch 7)
On 05/01/18 13:12, Will Deacon wrote: > Cortex-A57, A72, A73 and A75 are susceptible to branch predictor aliasing > and can theoretically be attacked by malicious code. > > This patch implements a PSCI-based mitigation for these CPUs when available. > The call into firmware will invalidate the branch predictor state, preventing > any malicious entries from affecting other victim contexts. > > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> > Signed-off-by: Will Deacon <will.deacon@arm.com>
> diff --git a/arch/arm64/kernel/bpi.S b/arch/arm64/kernel/bpi.S > index 06a931eb2673..2e9146534174 100644 > --- a/arch/arm64/kernel/bpi.S > +++ b/arch/arm64/kernel/bpi.S > @@ -53,3 +53,27 @@ ENTRY(__bp_harden_hyp_vecs_start) > vectors __kvm_hyp_vector > .endr > ENTRY(__bp_harden_hyp_vecs_end) > +ENTRY(__psci_hyp_bp_inval_start)
> + sub sp, sp, #(8 * 18)
Where does 18 come from? Isn't this storing 9 sets of 16 bytes?
> + stp x16, x17, [sp, #(16 * 0)] > + stp x14, x15, [sp, #(16 * 1)] > + stp x12, x13, [sp, #(16 * 2)] > + stp x10, x11, [sp, #(16 * 3)] > + stp x8, x9, [sp, #(16 * 4)] > + stp x6, x7, [sp, #(16 * 5)] > + stp x4, x5, [sp, #(16 * 6)] > + stp x2, x3, [sp, #(16 * 7)]
> + stp x0, x1, [sp, #(18 * 8)]
16->18 typo?
> + mov x0, #0x84000000 > + smc #0 > + ldp x16, x17, [sp, #(16 * 0)] > + ldp x14, x15, [sp, #(16 * 1)] > + ldp x12, x13, [sp, #(16 * 2)] > + ldp x10, x11, [sp, #(16 * 3)] > + ldp x8, x9, [sp, #(16 * 4)] > + ldp x6, x7, [sp, #(16 * 5)] > + ldp x4, x5, [sp, #(16 * 6)] > + ldp x2, x3, [sp, #(16 * 7)]
> + ldp x0, x1, [sp, #(18 * 8)] > + add sp, sp, #(8 * 18)
(and here?)
> +ENTRY(__psci_hyp_bp_inval_end)
Thanks,
James
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