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 shstk_free(tsk); \ 190 load_gs_index(0); \ 191 loadsegment(fs, 0); \ 192 } while (0) 193 #endif 194 195 static inline void arch_dup_pkeys(struct mm_struct *oldmm, 196 struct mm_struct *mm) 197 { 198 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS 199 if (!cpu_feature_enabled(X86_FEATURE_OSPKE)) 200 return; 201 202 /* Duplicate the oldmm pkey state in mm: */ 203 mm->context.pkey_allocation_map = oldmm->context.pkey_allocation_map; 204 mm->context.execute_only_pkey = oldmm->context.execute_only_pkey; 205 #endif 206 } 207 208 static inline int arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) 209 { 210 arch_dup_pkeys(oldmm, mm); 211 paravirt_enter_mmap(mm); 212 dup_lam(oldmm, mm); 213 return ldt_dup_context(oldmm, mm); 214 } 215 216 static inline void arch_exit_mmap(struct mm_struct *mm) 217 { 218 paravirt_arch_exit_mmap(mm); 219 ldt_arch_exit_mmap(mm); 220 } 221 222 #ifdef CONFIG_X86_64 223 static inline bool is_64bit_mm(struct mm_struct *mm) 224 { 225 return !IS_ENABLED(CONFIG_IA32_EMULATION) || 226 !test_bit(MM_CONTEXT_UPROBE_IA32, &mm->context.flags); 227 } 228 #else 229 static inline bool is_64bit_mm(struct mm_struct *mm) 230 { 231 return false; 232 } 233 #endif 234 235 static inline void arch_unmap(struct mm_struct *mm, unsigned long start, 236 unsigned long end) 237 { 238 } 239 240 /* 241 * We only want to enforce protection keys on the current process 242 * because we effectively have no access to PKRU for other 243 * processes or any way to tell *which * PKRU in a threaded 244 * process we could use. 245 * 246 * So do not enforce things if the VMA is not from the current 247 * mm, or if we are in a kernel thread. 248 */ 249 static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, 250 bool write, bool execute, bool foreign) 251 { 252 /* pkeys never affect instruction fetches */ 253 if (execute) 254 return true; 255 /* allow access if the VMA is not one from this process */ 256 if (foreign || vma_is_foreign(vma)) 257 return true; 258 return __pkru_allows_pkey(vma_pkey(vma), write); 259 } 260 261 unsigned long __get_current_cr3_fast(void); 262 263 #include <asm-generic/mmu_context.h> 264 265 #endif /* _ASM_X86_MMU_CONTEXT_H */ 266