1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Copyright (C) 2022 ARM Ltd.
4 */
5 #ifndef __ASM_VECTORS_H
6 #define __ASM_VECTORS_H
7
8 #include <linux/bug.h>
9 #include <linux/percpu.h>
10
11 #include <asm/fixmap.h>
12
13 extern char vectors[];
14 extern char tramp_vectors[];
15 extern char __bp_harden_el1_vectors[];
16
17 /*
18 * Note: the order of this enum corresponds to two arrays in entry.S:
19 * tramp_vecs and __bp_harden_el1_vectors. By default the canonical
20 * 'full fat' vectors are used directly.
21 */
22 enum arm64_bp_harden_el1_vectors {
23 #ifdef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY
24 /*
25 * Perform the BHB loop mitigation, before branching to the canonical
26 * vectors.
27 */
28 EL1_VECTOR_BHB_LOOP,
29
30 /*
31 * Make the SMC call for firmware mitigation, before branching to the
32 * canonical vectors.
33 */
34 EL1_VECTOR_BHB_FW,
35
36 /*
37 * Use the ClearBHB instruction, before branching to the canonical
38 * vectors.
39 */
40 EL1_VECTOR_BHB_CLEAR_INSN,
41 #endif /* CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY */
42
43 /*
44 * Remap the kernel before branching to the canonical vectors.
45 */
46 EL1_VECTOR_KPTI,
47 };
48
49 #ifndef CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY
50 #define EL1_VECTOR_BHB_LOOP -1
51 #define EL1_VECTOR_BHB_FW -1
52 #define EL1_VECTOR_BHB_CLEAR_INSN -1
53 #endif /* !CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY */
54
55 /* The vectors to use on return from EL0. e.g. to remap the kernel */
56 DECLARE_PER_CPU_READ_MOSTLY(const char *, this_cpu_vector);
57
58 #ifndef CONFIG_UNMAP_KERNEL_AT_EL0
59 #define TRAMP_VALIAS 0ul
60 #endif
61
62 static inline const char *
63 arm64_get_bp_hardening_vector(enum arm64_bp_harden_el1_vectors slot)
64 {
65 if (cpus_have_cap(ARM64_UNMAP_KERNEL_AT_EL0))
66 return (char *)(TRAMP_VALIAS + SZ_2K * slot);
67
68 WARN_ON_ONCE(slot == EL1_VECTOR_KPTI);
69
70 return __bp_harden_el1_vectors + SZ_2K * slot;
71 }
72
73 #endif /* __ASM_VECTORS_H */
74
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