1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 * Interface for managing mitigations for Spectre vulnerabilities.
  4 *
  5 * Copyright (C) 2020 Google LLC
  6 * Author: Will Deacon <will@kernel.org>
  7 */
  8
  9#ifndef __ASM_SPECTRE_H
 10#define __ASM_SPECTRE_H
 11
 12#define BP_HARDEN_EL2_SLOTS 4
 13#define __BP_HARDEN_HYP_VECS_SZ	((BP_HARDEN_EL2_SLOTS - 1) * SZ_2K)
 14
 15#ifndef __ASSEMBLY__
 16#include <linux/smp.h>
 17#include <asm/percpu.h>
 18
 19#include <asm/cpufeature.h>
 20#include <asm/virt.h>
 21
 22/* Watch out, ordering is important here. */
 23enum mitigation_state {
 24	SPECTRE_UNAFFECTED,
 25	SPECTRE_MITIGATED,
 26	SPECTRE_VULNERABLE,
 27};
 28
 29struct pt_regs;
 30struct task_struct;
 31
 32/*
 33 * Note: the order of this enum corresponds to __bp_harden_hyp_vecs and
 34 * we rely on having the direct vectors first.
 35 */
 36enum arm64_hyp_spectre_vector {
 37	/*
 38	 * Take exceptions directly to __kvm_hyp_vector. This must be
 39	 * 0 so that it used by default when mitigations are not needed.
 40	 */
 41	HYP_VECTOR_DIRECT,
 42
 43	/*
 44	 * Bounce via a slot in the hypervisor text mapping of
 45	 * __bp_harden_hyp_vecs, which contains an SMC call.
 46	 */
 47	HYP_VECTOR_SPECTRE_DIRECT,
 48
 49	/*
 50	 * Bounce via a slot in a special mapping of __bp_harden_hyp_vecs
 51	 * next to the idmap page.
 52	 */
 53	HYP_VECTOR_INDIRECT,
 54
 55	/*
 56	 * Bounce via a slot in a special mapping of __bp_harden_hyp_vecs
 57	 * next to the idmap page, which contains an SMC call.
 58	 */
 59	HYP_VECTOR_SPECTRE_INDIRECT,
 60};
 61
 62typedef void (*bp_hardening_cb_t)(void);
 63
 64struct bp_hardening_data {
 65	enum arm64_hyp_spectre_vector	slot;
 66	bp_hardening_cb_t		fn;
 67};
 68
 69DECLARE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data);
 70
 71/* Called during entry so must be __always_inline */
 72static __always_inline void arm64_apply_bp_hardening(void)
 73{
 74	struct bp_hardening_data *d;
 75
 76	if (!alternative_has_cap_unlikely(ARM64_SPECTRE_V2))
 77		return;
 78
 79	d = this_cpu_ptr(&bp_hardening_data);
 80	if (d->fn)
 81		d->fn();
 82}
 83
 84enum mitigation_state arm64_get_spectre_v2_state(void);
 85bool has_spectre_v2(const struct arm64_cpu_capabilities *cap, int scope);
 86void spectre_v2_enable_mitigation(const struct arm64_cpu_capabilities *__unused);
 87
 88bool has_spectre_v3a(const struct arm64_cpu_capabilities *cap, int scope);
 89void spectre_v3a_enable_mitigation(const struct arm64_cpu_capabilities *__unused);
 90
 91enum mitigation_state arm64_get_spectre_v4_state(void);
 92bool has_spectre_v4(const struct arm64_cpu_capabilities *cap, int scope);
 93void spectre_v4_enable_mitigation(const struct arm64_cpu_capabilities *__unused);
 94void spectre_v4_enable_task_mitigation(struct task_struct *tsk);
 95
 96enum mitigation_state arm64_get_meltdown_state(void);
 97
 98enum mitigation_state arm64_get_spectre_bhb_state(void);
 99bool is_spectre_bhb_affected(const struct arm64_cpu_capabilities *entry, int scope);
100u8 spectre_bhb_loop_affected(int scope);
101void spectre_bhb_enable_mitigation(const struct arm64_cpu_capabilities *__unused);
102bool try_emulate_el1_ssbs(struct pt_regs *regs, u32 instr);
103
104void spectre_v4_patch_fw_mitigation_enable(struct alt_instr *alt, __le32 *origptr,
105					   __le32 *updptr, int nr_inst);
106void smccc_patch_fw_mitigation_conduit(struct alt_instr *alt, __le32 *origptr,
107				       __le32 *updptr, int nr_inst);
108void spectre_bhb_patch_loop_mitigation_enable(struct alt_instr *alt, __le32 *origptr,
109					      __le32 *updptr, int nr_inst);
110void spectre_bhb_patch_fw_mitigation_enabled(struct alt_instr *alt, __le32 *origptr,
111					     __le32 *updptr, int nr_inst);
112void spectre_bhb_patch_loop_iter(struct alt_instr *alt,
113				 __le32 *origptr, __le32 *updptr, int nr_inst);
114void spectre_bhb_patch_wa3(struct alt_instr *alt,
115			   __le32 *origptr, __le32 *updptr, int nr_inst);
116void spectre_bhb_patch_clearbhb(struct alt_instr *alt,
117				__le32 *origptr, __le32 *updptr, int nr_inst);
118
119#endif	/* __ASSEMBLY__ */
120#endif	/* __ASM_SPECTRE_H */