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| author | Marc Zyngier <marc.zyngier@arm.com> | 2018-02-01 11:07:38 +0000 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2018-05-31 11:09:03 +0100 |
| commit | 0c47ac8cd157727e7a532d665d6fb1b5fd333977 (patch) | |
| tree | 3c2e82a8bfa1eac1f305e05221b61605b76718e8 /arch | |
| parent | 3f7e8e2e1ebda787f156ce46e3f0a9ce2833fa4f (diff) | |
| download | lwn-0c47ac8cd157727e7a532d665d6fb1b5fd333977.tar.gz lwn-0c47ac8cd157727e7a532d665d6fb1b5fd333977.zip | |
ARM: KVM: invalidate icache on guest exit for Cortex-A15
In order to avoid aliasing attacks against the branch predictor
on Cortex-A15, let's invalidate the BTB on guest exit, which can
only be done by invalidating the icache (with ACTLR[0] being set).
We use the same hack as for A12/A17 to perform the vector decoding.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
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>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm/include/asm/kvm_mmu.h | 5 | ||||
| -rw-r--r-- | arch/arm/kvm/hyp/hyp-entry.S | 24 |
2 files changed, 29 insertions, 0 deletions
diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h index d08ce9c41df4..48edb1f4ced4 100644 --- a/arch/arm/include/asm/kvm_mmu.h +++ b/arch/arm/include/asm/kvm_mmu.h @@ -306,6 +306,11 @@ static inline void *kvm_get_hyp_vector(void) return kvm_ksym_ref(__kvm_hyp_vector_bp_inv); } + case ARM_CPU_PART_CORTEX_A15: + { + extern char __kvm_hyp_vector_ic_inv[]; + return kvm_ksym_ref(__kvm_hyp_vector_ic_inv); + } #endif default: { diff --git a/arch/arm/kvm/hyp/hyp-entry.S b/arch/arm/kvm/hyp/hyp-entry.S index e789f52a5129..918a05dd2d63 100644 --- a/arch/arm/kvm/hyp/hyp-entry.S +++ b/arch/arm/kvm/hyp/hyp-entry.S @@ -73,6 +73,28 @@ __kvm_hyp_vector: #ifdef CONFIG_HARDEN_BRANCH_PREDICTOR .align 5 +__kvm_hyp_vector_ic_inv: + .global __kvm_hyp_vector_ic_inv + + /* + * We encode the exception entry in the bottom 3 bits of + * SP, and we have to guarantee to be 8 bytes aligned. + */ + W(add) sp, sp, #1 /* Reset 7 */ + W(add) sp, sp, #1 /* Undef 6 */ + W(add) sp, sp, #1 /* Syscall 5 */ + W(add) sp, sp, #1 /* Prefetch abort 4 */ + W(add) sp, sp, #1 /* Data abort 3 */ + W(add) sp, sp, #1 /* HVC 2 */ + W(add) sp, sp, #1 /* IRQ 1 */ + W(nop) /* FIQ 0 */ + + mcr p15, 0, r0, c7, c5, 0 /* ICIALLU */ + isb + + b decode_vectors + + .align 5 __kvm_hyp_vector_bp_inv: .global __kvm_hyp_vector_bp_inv @@ -92,6 +114,8 @@ __kvm_hyp_vector_bp_inv: mcr p15, 0, r0, c7, c5, 6 /* BPIALL */ isb +decode_vectors: + #ifdef CONFIG_THUMB2_KERNEL /* * Yet another silly hack: Use VPIDR as a temp register. |