diff options
| author | Russell King <rmk+kernel@armlinux.org.uk> | 2019-11-08 13:35:26 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-11-10 11:21:25 +0100 |
| commit | 521bb23af00c153223ec16032157df94dbff5717 (patch) | |
| tree | b1846b2d31cc3df90d64b52862070a0c1eb2a3d1 /arch/arm/mm/Kconfig | |
| parent | 22b1077759ad1f6de0864b589455550bd872e561 (diff) | |
ARM: spectre-v2: harden branch predictor on context switches
Commit 06c23f5ffe7ad45b908d0fff604dae08a7e334b9 upstream.
Required manual merge of arch/arm/mm/proc-v7.S.
Harden the branch predictor against Spectre v2 attacks on context
switches for ARMv7 and later CPUs. We do this by:
Cortex A9, A12, A17, A73, A75: invalidating the BTB.
Cortex A15, Brahma B15: invalidating the instruction cache.
Cortex A57 and Cortex A72 are not addressed in this patch.
Cortex R7 and Cortex R8 are also not addressed as we do not enforce
memory protection on these cores.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Boot-tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: David A. Long <dave.long@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arm/mm/Kconfig')
| -rw-r--r-- | arch/arm/mm/Kconfig | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig index 7ef92e6692ab..71115afb71a0 100644 --- a/arch/arm/mm/Kconfig +++ b/arch/arm/mm/Kconfig @@ -797,6 +797,25 @@ config CPU_BPREDICT_DISABLE config CPU_SPECTRE bool +config HARDEN_BRANCH_PREDICTOR + bool "Harden the branch predictor against aliasing attacks" if EXPERT + depends on CPU_SPECTRE + 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 TLS_REG_EMUL bool select NEED_KUSER_HELPERS |