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-rw-r--r--arch/arm64/include/asm/spectre.h102
1 files changed, 102 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/spectre.h b/arch/arm64/include/asm/spectre.h
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+++ b/arch/arm64/include/asm/spectre.h
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+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Interface for managing mitigations for Spectre vulnerabilities.
+ *
+ * Copyright (C) 2020 Google LLC
+ * Author: Will Deacon <will@kernel.org>
+ */
+
+#ifndef __ASM_SPECTRE_H
+#define __ASM_SPECTRE_H
+
+#define BP_HARDEN_EL2_SLOTS 4
+#define __BP_HARDEN_HYP_VECS_SZ ((BP_HARDEN_EL2_SLOTS - 1) * SZ_2K)
+
+#ifndef __ASSEMBLY__
+
+#include <linux/percpu.h>
+
+#include <asm/cpufeature.h>
+#include <asm/virt.h>
+
+/* Watch out, ordering is important here. */
+enum mitigation_state {
+ SPECTRE_UNAFFECTED,
+ SPECTRE_MITIGATED,
+ SPECTRE_VULNERABLE,
+};
+
+struct task_struct;
+
+/*
+ * Note: the order of this enum corresponds to __bp_harden_hyp_vecs and
+ * we rely on having the direct vectors first.
+ */
+enum arm64_hyp_spectre_vector {
+ /*
+ * Take exceptions directly to __kvm_hyp_vector. This must be
+ * 0 so that it used by default when mitigations are not needed.
+ */
+ HYP_VECTOR_DIRECT,
+
+ /*
+ * Bounce via a slot in the hypervisor text mapping of
+ * __bp_harden_hyp_vecs, which contains an SMC call.
+ */
+ HYP_VECTOR_SPECTRE_DIRECT,
+
+ /*
+ * Bounce via a slot in a special mapping of __bp_harden_hyp_vecs
+ * next to the idmap page.
+ */
+ HYP_VECTOR_INDIRECT,
+
+ /*
+ * Bounce via a slot in a special mapping of __bp_harden_hyp_vecs
+ * next to the idmap page, which contains an SMC call.
+ */
+ HYP_VECTOR_SPECTRE_INDIRECT,
+};
+
+typedef void (*bp_hardening_cb_t)(void);
+
+struct bp_hardening_data {
+ enum arm64_hyp_spectre_vector slot;
+ bp_hardening_cb_t fn;
+};
+
+DECLARE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data);
+
+/* Called during entry so must be __always_inline */
+static __always_inline void arm64_apply_bp_hardening(void)
+{
+ struct bp_hardening_data *d;
+
+ if (!cpus_have_const_cap(ARM64_SPECTRE_V2))
+ return;
+
+ d = this_cpu_ptr(&bp_hardening_data);
+ if (d->fn)
+ d->fn();
+}
+
+enum mitigation_state arm64_get_spectre_v2_state(void);
+bool has_spectre_v2(const struct arm64_cpu_capabilities *cap, int scope);
+void spectre_v2_enable_mitigation(const struct arm64_cpu_capabilities *__unused);
+
+bool has_spectre_v3a(const struct arm64_cpu_capabilities *cap, int scope);
+void spectre_v3a_enable_mitigation(const struct arm64_cpu_capabilities *__unused);
+
+enum mitigation_state arm64_get_spectre_v4_state(void);
+bool has_spectre_v4(const struct arm64_cpu_capabilities *cap, int scope);
+void spectre_v4_enable_mitigation(const struct arm64_cpu_capabilities *__unused);
+void spectre_v4_enable_task_mitigation(struct task_struct *tsk);
+
+enum mitigation_state arm64_get_meltdown_state(void);
+
+enum mitigation_state arm64_get_spectre_bhb_state(void);
+bool is_spectre_bhb_affected(const struct arm64_cpu_capabilities *entry, int scope);
+u8 spectre_bhb_loop_affected(int scope);
+void spectre_bhb_enable_mitigation(const struct arm64_cpu_capabilities *__unused);
+#endif /* __ASSEMBLY__ */
+#endif /* __ASM_SPECTRE_H */