[PATCH ARM64 v4.4 V3 31/44] arm64: Implement branch predictor hardening for affected Cortex-A CPUs
From: Viresh Kumar <viresh.kumar@linaro.org>
Date: 2019-08-29 11:36:16
Also in:
stable
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
From: Will Deacon <redacted> commit aa6acde65e03186b5add8151e1ffe36c3c62639b upstream. 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. Co-developed-by: Marc Zyngier <redacted> Signed-off-by: Will Deacon <redacted> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> --- arch/arm64/kernel/bpi.S | 24 +++++++++++++++++++ arch/arm64/kernel/cpu_errata.c | 42 ++++++++++++++++++++++++++++++++++ 2 files changed, 66 insertions(+)
diff --git a/arch/arm64/kernel/bpi.S b/arch/arm64/kernel/bpi.S
index 06a931eb2673..dec95bd82e31 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) + 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, #(16 * 8)] + 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, #(16 * 8)] + add sp, sp, #(8 * 18) +ENTRY(__psci_hyp_bp_inval_end)
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 80765feae955..dbd7b944a37e 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c@@ -50,6 +50,8 @@ is_affected_midr_range(const struct arm64_cpu_capabilities *entry, int scope) 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[]; + static void __copy_hyp_vect_bpi(int slot, const char *hyp_vecs_start, const char *hyp_vecs_end) {
@@ -91,6 +93,9 @@ 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 + static void __install_bp_hardening_cb(bp_hardening_cb_t fn, const char *hyp_vecs_start, const char *hyp_vecs_end)
@@ -115,6 +120,21 @@ static void install_bp_hardening_cb(const struct arm64_cpu_capabilities *entry, __install_bp_hardening_cb(fn, hyp_vecs_start, hyp_vecs_end); } + +#include <linux/psci.h> + +static int enable_psci_bp_hardening(void *data) +{ + const struct arm64_cpu_capabilities *entry = data; + + if (psci_ops.get_version) + install_bp_hardening_cb(entry, + (bp_hardening_cb_t)psci_ops.get_version, + __psci_hyp_bp_inval_start, + __psci_hyp_bp_inval_end); + + return 0; +} #endif /* CONFIG_HARDEN_BRANCH_PREDICTOR */ #define MIDR_RANGE(model, min, max) \
@@ -192,6 +212,28 @@ const struct arm64_cpu_capabilities arm64_errata[] = { MIDR_RANGE(MIDR_THUNDERX, 0x00, (1 << MIDR_VARIANT_SHIFT) | 1), }, +#endif +#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR + { + .capability = ARM64_HARDEN_BRANCH_PREDICTOR, + MIDR_ALL_VERSIONS(MIDR_CORTEX_A57), + .enable = enable_psci_bp_hardening, + }, + { + .capability = ARM64_HARDEN_BRANCH_PREDICTOR, + MIDR_ALL_VERSIONS(MIDR_CORTEX_A72), + .enable = enable_psci_bp_hardening, + }, + { + .capability = ARM64_HARDEN_BRANCH_PREDICTOR, + MIDR_ALL_VERSIONS(MIDR_CORTEX_A73), + .enable = enable_psci_bp_hardening, + }, + { + .capability = ARM64_HARDEN_BRANCH_PREDICTOR, + MIDR_ALL_VERSIONS(MIDR_CORTEX_A75), + .enable = enable_psci_bp_hardening, + }, #endif { }
--
2.21.0.rc0.269.g1a574e7a288b
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel