From: Julien Grall Date: Tue, 12 Jun 2018 11:36:41 +0000 (+0100) Subject: xen/arm: Kconfig: Move HARDEN_BRANCH_PREDICTOR under "Architecture features" X-Git-Tag: archive/raspbian/4.14.0+80-gd101b417b7-1+rpi1^2~63^2~3704^2~2 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=54cf710d74720a94b9d9a7e58abbe2831e70a37b;p=xen.git xen/arm: Kconfig: Move HARDEN_BRANCH_PREDICTOR under "Architecture features" At the moment, HARDEN_BRANCH_PREDICTOR is not in any section making impossible for the user to unselect it. Also, it looks like we require to use 'expert = "y"' for showing the option in expert mode. Signed-off-by: Julien Grall Reviewed-by: Stefano Stabellini --- diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig index 2cbe9dd43b..06ba4a4d6e 100644 --- a/xen/arch/arm/Kconfig +++ b/xen/arch/arm/Kconfig @@ -81,6 +81,23 @@ config ARM_SSBD If unsure, say Y. +config HARDEN_BRANCH_PREDICTOR + bool "Harden the branch predictor against aliasing attacks" if EXPERT = "y" + default y + help + Speculation attacks against some high-performance processors rely on + being able to manipulate the branch predictor for a victim context by + executing aliasing branches in the attacker context. Such attacks + can be partially mitigated against by clearing internal branch + predictor state and limiting the prediction logic in some situations. + + This config option will take CPU-specific actions to harden the + branch predictor against aliasing attacks and may rely on specific + instruction sequences or control bits being set by the system + firmware. + + If unsure, say Y. + endmenu menu "ARM errata workaround via the alternative framework" @@ -195,23 +212,6 @@ config ARM64_ERRATUM_834220 endmenu -config HARDEN_BRANCH_PREDICTOR - bool "Harden the branch predictor against aliasing attacks" if EXPERT - default y - help - Speculation attacks against some high-performance processors rely on - being able to manipulate the branch predictor for a victim context by - executing aliasing branches in the attacker context. Such attacks - can be partially mitigated against by clearing internal branch - predictor state and limiting the prediction logic in some situations. - - This config option will take CPU-specific actions to harden the - branch predictor against aliasing attacks and may rely on specific - instruction sequences or control bits being set by the system - firmware. - - If unsure, say Y. - config ARM64_HARDEN_BRANCH_PREDICTOR def_bool y if ARM_64 && HARDEN_BRANCH_PREDICTOR