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