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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 pt_regs;
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);
bool try_emulate_el1_ssbs(struct pt_regs *regs, u32 instr);
#endif /* __ASSEMBLY__ */
#endif /* __ASM_SPECTRE_H */
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