1 /* 2 * Copyright (C) 2012 ARM Ltd. 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program. If not, see <http://www.gnu.org/licenses/>. 15 */ 16 #ifndef __ASM_MMU_H 17 #define __ASM_MMU_H 18 19 #include <asm/cputype.h> 20 21 #define MMCF_AARCH32 0x1 /* mm context flag for AArch32 executables */ 22 #define USER_ASID_BIT 48 23 #define USER_ASID_FLAG (UL(1) << USER_ASID_BIT) 24 #define TTBR_ASID_MASK (UL(0xffff) << 48) 25 26 #define BP_HARDEN_EL2_SLOTS 4 27 28 #ifndef __ASSEMBLY__ 29 30 typedef struct { 31 atomic64_t id; 32 void *vdso; 33 unsigned long flags; 34 } mm_context_t; 35 36 /* 37 * This macro is only used by the TLBI code, which cannot race with an 38 * ASID change and therefore doesn't need to reload the counter using 39 * atomic64_read. 40 */ 41 #define ASID(mm) ((mm)->context.id.counter & 0xffff) 42 43 static inline bool arm64_kernel_unmapped_at_el0(void) 44 { 45 return IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0) && 46 cpus_have_const_cap(ARM64_UNMAP_KERNEL_AT_EL0); 47 } 48 49 static inline bool arm64_kernel_use_ng_mappings(void) 50 { 51 bool tx1_bug; 52 53 /* What's a kpti? Use global mappings if we don't know. */ 54 if (!IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0)) 55 return false; 56 57 /* 58 * Note: this function is called before the CPU capabilities have 59 * been configured, so our early mappings will be global. If we 60 * later determine that kpti is required, then 61 * kpti_install_ng_mappings() will make them non-global. 62 */ 63 if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE)) 64 return arm64_kernel_unmapped_at_el0(); 65 66 /* 67 * KASLR is enabled so we're going to be enabling kpti on non-broken 68 * CPUs regardless of their susceptibility to Meltdown. Rather 69 * than force everybody to go through the G -> nG dance later on, 70 * just put down non-global mappings from the beginning. 71 */ 72 if (!IS_ENABLED(CONFIG_CAVIUM_ERRATUM_27456)) { 73 tx1_bug = false; 74 #ifndef MODULE 75 } else if (!static_branch_likely(&arm64_const_caps_ready)) { 76 extern const struct midr_range cavium_erratum_27456_cpus[]; 77 78 tx1_bug = is_midr_in_range_list(read_cpuid_id(), 79 cavium_erratum_27456_cpus); 80 #endif 81 } else { 82 tx1_bug = __cpus_have_const_cap(ARM64_WORKAROUND_CAVIUM_27456); 83 } 84 85 return !tx1_bug && kaslr_offset() > 0; 86 } 87 88 typedef void (*bp_hardening_cb_t)(void); 89 90 struct bp_hardening_data { 91 int hyp_vectors_slot; 92 bp_hardening_cb_t fn; 93 }; 94 95 #if (defined(CONFIG_HARDEN_BRANCH_PREDICTOR) || \ 96 defined(CONFIG_HARDEN_EL2_VECTORS)) 97 extern char __bp_harden_hyp_vecs_start[], __bp_harden_hyp_vecs_end[]; 98 extern atomic_t arm64_el2_vector_last_slot; 99 #endif /* CONFIG_HARDEN_BRANCH_PREDICTOR || CONFIG_HARDEN_EL2_VECTORS */ 100 101 #ifdef CONFIG_HARDEN_BRANCH_PREDICTOR 102 DECLARE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data); 103 104 static inline struct bp_hardening_data *arm64_get_bp_hardening_data(void) 105 { 106 return this_cpu_ptr(&bp_hardening_data); 107 } 108 109 static inline void arm64_apply_bp_hardening(void) 110 { 111 struct bp_hardening_data *d; 112 113 if (!cpus_have_const_cap(ARM64_HARDEN_BRANCH_PREDICTOR)) 114 return; 115 116 d = arm64_get_bp_hardening_data(); 117 if (d->fn) 118 d->fn(); 119 } 120 #else 121 static inline struct bp_hardening_data *arm64_get_bp_hardening_data(void) 122 { 123 return NULL; 124 } 125 126 static inline void arm64_apply_bp_hardening(void) { } 127 #endif /* CONFIG_HARDEN_BRANCH_PREDICTOR */ 128 129 extern void paging_init(void); 130 extern void bootmem_init(void); 131 extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt); 132 extern void init_mem_pgprot(void); 133 extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, 134 unsigned long virt, phys_addr_t size, 135 pgprot_t prot, bool page_mappings_only); 136 extern void *fixmap_remap_fdt(phys_addr_t dt_phys); 137 extern void mark_linear_text_alias_ro(void); 138 139 #define INIT_MM_CONTEXT(name) \ 140 .pgd = init_pg_dir, 141 142 #endif /* !__ASSEMBLY__ */ 143 #endif 144