1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_X86_MMU_CONTEXT_H 3 #define _ASM_X86_MMU_CONTEXT_H 4 5 #include <asm/desc.h> 6 #include <linux/atomic.h> 7 #include <linux/mm_types.h> 8 #include <linux/pkeys.h> 9 10 #include <trace/events/tlb.h> 11 12 #include <asm/tlbflush.h> 13 #include <asm/paravirt.h> 14 #include <asm/debugreg.h> 15 #include <asm/gsseg.h> 16 17 extern atomic64_t last_mm_ctx_id; 18 19 #ifdef CONFIG_PERF_EVENTS 20 DECLARE_STATIC_KEY_FALSE(rdpmc_never_available_key); 21 DECLARE_STATIC_KEY_FALSE(rdpmc_always_available_key); 22 void cr4_update_pce(void *ignored); 23 #endif 24 25 #ifdef CONFIG_MODIFY_LDT_SYSCALL 26 /* 27 * ldt_structs can be allocated, used, and freed, but they are never 28 * modified while live. 29 */ 30 struct ldt_struct { 31 /* 32 * Xen requires page-aligned LDTs with special permissions. This is 33 * needed to prevent us from installing evil descriptors such as 34 * call gates. On native, we could merge the ldt_struct and LDT 35 * allocations, but it's not worth trying to optimize. 36 */ 37 struct desc_struct *entries; 38 unsigned int nr_entries; 39 40 /* 41 * If PTI is in use, then the entries array is not mapped while we're 42 * in user mode. The whole array will be aliased at the addressed 43 * given by ldt_slot_va(slot). We use two slots so that we can allocate 44 * and map, and enable a new LDT without invalidating the mapping 45 * of an older, still-in-use LDT. 46 * 47 * slot will be -1 if this LDT doesn't have an alias mapping. 48 */ 49 int slot; 50 }; 51 52 /* 53 * Used for LDT copy/destruction. 54 */ 55 static inline void init_new_context_ldt(struct mm_struct *mm) 56 { 57 mm->context.ldt = NULL; 58 init_rwsem(&mm->context.ldt_usr_sem); 59 } 60 int ldt_dup_context(struct mm_struct *oldmm, struct mm_struct *mm); 61 void destroy_context_ldt(struct mm_struct *mm); 62 void ldt_arch_exit_mmap(struct mm_struct *mm); 63 #else /* CONFIG_MODIFY_LDT_SYSCALL */ 64 static inline void init_new_context_ldt(struct mm_struct *mm) { } 65 static inline int ldt_dup_context(struct mm_struct *oldmm, 66 struct mm_struct *mm) 67 { 68 return 0; 69 } 70 static inline void destroy_context_ldt(struct mm_struct *mm) { } 71 static inline void ldt_arch_exit_mmap(struct mm_struct *mm) { } 72 #endif 73 74 #ifdef CONFIG_MODIFY_LDT_SYSCALL 75 extern void load_mm_ldt(struct mm_struct *mm); 76 extern void switch_ldt(struct mm_struct *prev, struct mm_struct *next); 77 #else 78 static inline void load_mm_ldt(struct mm_struct *mm) 79 { 80 clear_LDT(); 81 } 82 static inline void switch_ldt(struct mm_struct *prev, struct mm_struct *next) 83 { 84 DEBUG_LOCKS_WARN_ON(preemptible()); 85 } 86 #endif 87 88 #ifdef CONFIG_ADDRESS_MASKING 89 static inline unsigned long mm_lam_cr3_mask(struct mm_struct *mm) 90 { 91 return mm->context.lam_cr3_mask; 92 } 93 94 static inline void dup_lam(struct mm_struct *oldmm, struct mm_struct *mm) 95 { 96 mm->context.lam_cr3_mask = oldmm->context.lam_cr3_mask; 97 mm->context.untag_mask = oldmm->context.untag_mask; 98 } 99 100 #define mm_untag_mask mm_untag_mask 101 static inline unsigned long mm_untag_mask(struct mm_struct *mm) 102 { 103 return mm->context.untag_mask; 104 } 105 106 static inline void mm_reset_untag_mask(struct mm_struct *mm) 107 { 108 mm->context.untag_mask = -1UL; 109 } 110 111 #define arch_pgtable_dma_compat arch_pgtable_dma_compat 112 static inline bool arch_pgtable_dma_compat(struct mm_struct *mm) 113 { 114 return !mm_lam_cr3_mask(mm) || 115 test_bit(MM_CONTEXT_FORCE_TAGGED_SVA, &mm->context.flags); 116 } 117 #else 118 119 static inline unsigned long mm_lam_cr3_mask(struct mm_struct *mm) 120 { 121 return 0; 122 } 123 124 static inline void dup_lam(struct mm_struct *oldmm, struct mm_struct *mm) 125 { 126 } 127 128 static inline void mm_reset_untag_mask(struct mm_struct *mm) 129 { 130 } 131 #endif 132 133 #define enter_lazy_tlb enter_lazy_tlb 134 extern void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk); 135 136 /* 137 * Init a new mm. Used on mm copies, like at fork() 138 * and on mm's that are brand-new, like at execve(). 139 */ 140 #define init_new_context init_new_context 141 static inline int init_new_context(struct task_struct *tsk, 142 struct mm_struct *mm) 143 { 144 mutex_init(&mm->context.lock); 145 146 mm->context.ctx_id = atomic64_inc_return(&last_mm_ctx_id); 147 atomic64_set(&mm->context.tlb_gen, 0); 148 149 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS 150 if (cpu_feature_enabled(X86_FEATURE_OSPKE)) { 151 /* pkey 0 is the default and allocated implicitly */ 152 mm->context.pkey_allocation_map = 0x1; 153 /* -1 means unallocated or invalid */ 154 mm->context.execute_only_pkey = -1; 155 } 156 #endif 157 mm_reset_untag_mask(mm); 158 init_new_context_ldt(mm); 159 return 0; 160 } 161 162 #define destroy_context destroy_context 163 static inline void destroy_context(struct mm_struct *mm) 164 { 165 destroy_context_ldt(mm); 166 } 167 168 extern void switch_mm(struct mm_struct *prev, struct mm_struct *next, 169 struct task_struct *tsk); 170 171 extern void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, 172 struct task_struct *tsk); 173 #define switch_mm_irqs_off switch_mm_irqs_off 174 175 #define activate_mm(prev, next) \ 176 do { \ 177 paravirt_enter_mmap(next); \ 178 switch_mm((prev), (next), NULL); \ 179 } while (0); 180 181 #ifdef CONFIG_X86_32 182 #define deactivate_mm(tsk, mm) \ 183 do { \ 184 loadsegment(gs, 0); \ 185 } while (0) 186 #else 187 #define deactivate_mm(tsk, mm) \ 188 do { \ 189 load_gs_index(0); \ 190 loadsegment(fs, 0); \ 191 } while (0) 192 #endif 193 194 static inline void arch_dup_pkeys(struct mm_struct *oldmm, 195 struct mm_struct *mm) 196 { 197 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS 198 if (!cpu_feature_enabled(X86_FEATURE_OSPKE)) 199 return; 200 201 /* Duplicate the oldmm pkey state in mm: */ 202 mm->context.pkey_allocation_map = oldmm->context.pkey_allocation_map; 203 mm->context.execute_only_pkey = oldmm->context.execute_only_pkey; 204 #endif 205 } 206 207 static inline int arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) 208 { 209 arch_dup_pkeys(oldmm, mm); 210 paravirt_enter_mmap(mm); 211 dup_lam(oldmm, mm); 212 return ldt_dup_context(oldmm, mm); 213 } 214 215 static inline void arch_exit_mmap(struct mm_struct *mm) 216 { 217 paravirt_arch_exit_mmap(mm); 218 ldt_arch_exit_mmap(mm); 219 } 220 221 #ifdef CONFIG_X86_64 222 static inline bool is_64bit_mm(struct mm_struct *mm) 223 { 224 return !IS_ENABLED(CONFIG_IA32_EMULATION) || 225 !test_bit(MM_CONTEXT_UPROBE_IA32, &mm->context.flags); 226 } 227 #else 228 static inline bool is_64bit_mm(struct mm_struct *mm) 229 { 230 return false; 231 } 232 #endif 233 234 static inline void arch_unmap(struct mm_struct *mm, unsigned long start, 235 unsigned long end) 236 { 237 } 238 239 /* 240 * We only want to enforce protection keys on the current process 241 * because we effectively have no access to PKRU for other 242 * processes or any way to tell *which * PKRU in a threaded 243 * process we could use. 244 * 245 * So do not enforce things if the VMA is not from the current 246 * mm, or if we are in a kernel thread. 247 */ 248 static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, 249 bool write, bool execute, bool foreign) 250 { 251 /* pkeys never affect instruction fetches */ 252 if (execute) 253 return true; 254 /* allow access if the VMA is not one from this process */ 255 if (foreign || vma_is_foreign(vma)) 256 return true; 257 return __pkru_allows_pkey(vma_pkey(vma), write); 258 } 259 260 unsigned long __get_current_cr3_fast(void); 261 262 #include <asm-generic/mmu_context.h> 263 264 #endif /* _ASM_X86_MMU_CONTEXT_H */ 265