diff options
author | Shanker Donthineni <shankerd@codeaurora.org> | 2018-01-05 14:28:59 -0600 |
---|---|---|
committer | Catalin Marinas <catalin.marinas@arm.com> | 2018-01-08 18:47:07 +0000 |
commit | ec82b567a74fbdffdf418d4bb381d55f6a9096af (patch) | |
tree | 2f2320743f4d3c73044dba107850bde53644f907 /arch/arm64/kernel | |
parent | aa6acde65e03186b5add8151e1ffe36c3c62639b (diff) |
arm64: Implement branch predictor hardening for Falkor
Falkor is susceptible to branch predictor aliasing and can
theoretically be attacked by malicious code. This patch
implements a mitigation for these attacks, preventing any
malicious entries from affecting other victim contexts.
Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
[will: fix label name when !CONFIG_KVM and remove references to MIDR_FALKOR]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel')
-rw-r--r-- | arch/arm64/kernel/bpi.S | 8 | ||||
-rw-r--r-- | arch/arm64/kernel/cpu_errata.c | 40 |
2 files changed, 46 insertions, 2 deletions
diff --git a/arch/arm64/kernel/bpi.S b/arch/arm64/kernel/bpi.S index dec95bd82e31..76225c2611ea 100644 --- a/arch/arm64/kernel/bpi.S +++ b/arch/arm64/kernel/bpi.S @@ -77,3 +77,11 @@ ENTRY(__psci_hyp_bp_inval_start) ldp x0, x1, [sp, #(16 * 8)] add sp, sp, #(8 * 18) ENTRY(__psci_hyp_bp_inval_end) + +ENTRY(__qcom_hyp_sanitize_link_stack_start) + stp x29, x30, [sp, #-16]! + .rept 16 + bl . + 4 + .endr + ldp x29, x30, [sp], #16 +ENTRY(__qcom_hyp_sanitize_link_stack_end) diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index cb0fb3796bb8..70e5f1826fd9 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -54,6 +54,8 @@ DEFINE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data); #ifdef CONFIG_KVM extern char __psci_hyp_bp_inval_start[], __psci_hyp_bp_inval_end[]; +extern char __qcom_hyp_sanitize_link_stack_start[]; +extern char __qcom_hyp_sanitize_link_stack_end[]; static void __copy_hyp_vect_bpi(int slot, const char *hyp_vecs_start, const char *hyp_vecs_end) @@ -96,8 +98,10 @@ static void __install_bp_hardening_cb(bp_hardening_cb_t fn, spin_unlock(&bp_lock); } #else -#define __psci_hyp_bp_inval_start NULL -#define __psci_hyp_bp_inval_end NULL +#define __psci_hyp_bp_inval_start NULL +#define __psci_hyp_bp_inval_end NULL +#define __qcom_hyp_sanitize_link_stack_start NULL +#define __qcom_hyp_sanitize_link_stack_end NULL static void __install_bp_hardening_cb(bp_hardening_cb_t fn, const char *hyp_vecs_start, @@ -138,6 +142,29 @@ static int enable_psci_bp_hardening(void *data) return 0; } + +static void qcom_link_stack_sanitization(void) +{ + u64 tmp; + + asm volatile("mov %0, x30 \n" + ".rept 16 \n" + "bl . + 4 \n" + ".endr \n" + "mov x30, %0 \n" + : "=&r" (tmp)); +} + +static int qcom_enable_link_stack_sanitization(void *data) +{ + const struct arm64_cpu_capabilities *entry = data; + + install_bp_hardening_cb(entry, qcom_link_stack_sanitization, + __qcom_hyp_sanitize_link_stack_start, + __qcom_hyp_sanitize_link_stack_end); + + return 0; +} #endif /* CONFIG_HARDEN_BRANCH_PREDICTOR */ #define MIDR_RANGE(model, min, max) \ @@ -302,6 +329,15 @@ const struct arm64_cpu_capabilities arm64_errata[] = { MIDR_ALL_VERSIONS(MIDR_CORTEX_A75), .enable = enable_psci_bp_hardening, }, + { + .capability = ARM64_HARDEN_BRANCH_PREDICTOR, + MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR_V1), + .enable = qcom_enable_link_stack_sanitization, + }, + { + .capability = ARM64_HARDEN_BP_POST_GUEST_EXIT, + MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR_V1), + }, #endif { } |