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>
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Catalin Marinas

parent
aa6acde65e
commit
ec82b567a7
@@ -54,6 +54,8 @@ DEFINE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data);
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#ifdef CONFIG_KVM
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extern char __psci_hyp_bp_inval_start[], __psci_hyp_bp_inval_end[];
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extern char __qcom_hyp_sanitize_link_stack_start[];
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extern char __qcom_hyp_sanitize_link_stack_end[];
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static void __copy_hyp_vect_bpi(int slot, const char *hyp_vecs_start,
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const char *hyp_vecs_end)
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@@ -96,8 +98,10 @@ static void __install_bp_hardening_cb(bp_hardening_cb_t fn,
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spin_unlock(&bp_lock);
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}
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#else
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#define __psci_hyp_bp_inval_start NULL
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#define __psci_hyp_bp_inval_end NULL
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#define __psci_hyp_bp_inval_start NULL
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#define __psci_hyp_bp_inval_end NULL
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#define __qcom_hyp_sanitize_link_stack_start NULL
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#define __qcom_hyp_sanitize_link_stack_end NULL
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static void __install_bp_hardening_cb(bp_hardening_cb_t fn,
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const char *hyp_vecs_start,
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@@ -138,6 +142,29 @@ static int enable_psci_bp_hardening(void *data)
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return 0;
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}
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static void qcom_link_stack_sanitization(void)
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{
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u64 tmp;
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asm volatile("mov %0, x30 \n"
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".rept 16 \n"
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"bl . + 4 \n"
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".endr \n"
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"mov x30, %0 \n"
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: "=&r" (tmp));
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}
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static int qcom_enable_link_stack_sanitization(void *data)
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{
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const struct arm64_cpu_capabilities *entry = data;
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install_bp_hardening_cb(entry, qcom_link_stack_sanitization,
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__qcom_hyp_sanitize_link_stack_start,
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__qcom_hyp_sanitize_link_stack_end);
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return 0;
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}
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#endif /* CONFIG_HARDEN_BRANCH_PREDICTOR */
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#define MIDR_RANGE(model, min, max) \
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@@ -302,6 +329,15 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
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MIDR_ALL_VERSIONS(MIDR_CORTEX_A75),
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.enable = enable_psci_bp_hardening,
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},
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{
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.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
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MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR_V1),
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.enable = qcom_enable_link_stack_sanitization,
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},
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{
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.capability = ARM64_HARDEN_BP_POST_GUEST_EXIT,
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MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR_V1),
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},
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#endif
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{
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}
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