1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_X86_MMU_CONTEXT_H 3 #define _ASM_X86_MMU_CONTEXT_H 4 5 #include <linux/atomic.h> 6 #include <linux/mm_types.h> 7 #include <linux/pkeys.h> 8 9 #include <trace/events/tlb.h> 10 11 #include <asm/tlbflush.h> 12 #include <asm/paravirt.h> 13 #include <asm/debugreg.h> 14 #include <asm/gsseg.h> 15 #include <asm/desc.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 /* 92 * When switch_mm_irqs_off() is called for a kthread, it may race with 93 * LAM enablement. switch_mm_irqs_off() uses the LAM mask to do two 94 * things: populate CR3 and populate 'cpu_tlbstate.lam'. Make sure it 95 * reads a single value for both. 96 */ 97 return READ_ONCE(mm->context.lam_cr3_mask); 98 } 99 100 static inline void dup_lam(struct mm_struct *oldmm, struct mm_struct *mm) 101 { 102 mm->context.lam_cr3_mask = oldmm->context.lam_cr3_mask; 103 mm->context.untag_mask = oldmm->context.untag_mask; 104 } 105 106 #define mm_untag_mask mm_untag_mask 107 static inline unsigned long mm_untag_mask(struct mm_struct *mm) 108 { 109 return mm->context.untag_mask; 110 } 111 112 static inline void mm_reset_untag_mask(struct mm_struct *mm) 113 { 114 mm->context.untag_mask = -1UL; 115 } 116 117 #define arch_pgtable_dma_compat arch_pgtable_dma_compat 118 static inline bool arch_pgtable_dma_compat(struct mm_struct *mm) 119 { 120 return !mm_lam_cr3_mask(mm) || 121 test_bit(MM_CONTEXT_FORCE_TAGGED_SVA, &mm->context.flags); 122 } 123 #else 124 125 static inline unsigned long mm_lam_cr3_mask(struct mm_struct *mm) 126 { 127 return 0; 128 } 129 130 static inline void dup_lam(struct mm_struct *oldmm, struct mm_struct *mm) 131 { 132 } 133 134 static inline void mm_reset_untag_mask(struct mm_struct *mm) 135 { 136 } 137 #endif 138 139 #define enter_lazy_tlb enter_lazy_tlb 140 extern void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk); 141 142 #define mm_init_global_asid mm_init_global_asid 143 extern void mm_init_global_asid(struct mm_struct *mm); 144 145 extern void mm_free_global_asid(struct mm_struct *mm); 146 147 /* 148 * Init a new mm. Used on mm copies, like at fork() 149 * and on mm's that are brand-new, like at execve(). 150 */ 151 #define init_new_context init_new_context 152 static inline int init_new_context(struct task_struct *tsk, 153 struct mm_struct *mm) 154 { 155 mutex_init(&mm->context.lock); 156 157 mm->context.ctx_id = atomic64_inc_return(&last_mm_ctx_id); 158 atomic64_set(&mm->context.tlb_gen, 0); 159 mm->context.next_trim_cpumask = jiffies + HZ; 160 161 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS 162 if (cpu_feature_enabled(X86_FEATURE_OSPKE)) { 163 /* pkey 0 is the default and allocated implicitly */ 164 mm->context.pkey_allocation_map = 0x1; 165 /* -1 means unallocated or invalid */ 166 mm->context.execute_only_pkey = -1; 167 } 168 #endif 169 170 mm_init_global_asid(mm); 171 mm_reset_untag_mask(mm); 172 init_new_context_ldt(mm); 173 return 0; 174 } 175 176 #define destroy_context destroy_context 177 static inline void destroy_context(struct mm_struct *mm) 178 { 179 destroy_context_ldt(mm); 180 mm_free_global_asid(mm); 181 } 182 183 extern void switch_mm(struct mm_struct *prev, struct mm_struct *next, 184 struct task_struct *tsk); 185 186 extern void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, 187 struct task_struct *tsk); 188 #define switch_mm_irqs_off switch_mm_irqs_off 189 190 #define activate_mm(prev, next) \ 191 do { \ 192 paravirt_enter_mmap(next); \ 193 switch_mm((prev), (next), NULL); \ 194 } while (0); 195 196 #ifdef CONFIG_X86_32 197 #define deactivate_mm(tsk, mm) \ 198 do { \ 199 loadsegment(gs, 0); \ 200 } while (0) 201 #else 202 #define deactivate_mm(tsk, mm) \ 203 do { \ 204 shstk_free(tsk); \ 205 load_gs_index(0); \ 206 loadsegment(fs, 0); \ 207 } while (0) 208 #endif 209 210 static inline void arch_dup_pkeys(struct mm_struct *oldmm, 211 struct mm_struct *mm) 212 { 213 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS 214 if (!cpu_feature_enabled(X86_FEATURE_OSPKE)) 215 return; 216 217 /* Duplicate the oldmm pkey state in mm: */ 218 mm->context.pkey_allocation_map = oldmm->context.pkey_allocation_map; 219 mm->context.execute_only_pkey = oldmm->context.execute_only_pkey; 220 #endif 221 } 222 223 static inline int arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) 224 { 225 arch_dup_pkeys(oldmm, mm); 226 paravirt_enter_mmap(mm); 227 dup_lam(oldmm, mm); 228 return ldt_dup_context(oldmm, mm); 229 } 230 231 static inline void arch_exit_mmap(struct mm_struct *mm) 232 { 233 paravirt_arch_exit_mmap(mm); 234 ldt_arch_exit_mmap(mm); 235 } 236 237 #ifdef CONFIG_X86_64 238 static inline bool is_64bit_mm(struct mm_struct *mm) 239 { 240 return !IS_ENABLED(CONFIG_IA32_EMULATION) || 241 !test_bit(MM_CONTEXT_UPROBE_IA32, &mm->context.flags); 242 } 243 #else 244 static inline bool is_64bit_mm(struct mm_struct *mm) 245 { 246 return false; 247 } 248 #endif 249 250 /* 251 * We only want to enforce protection keys on the current process 252 * because we effectively have no access to PKRU for other 253 * processes or any way to tell *which * PKRU in a threaded 254 * process we could use. 255 * 256 * So do not enforce things if the VMA is not from the current 257 * mm, or if we are in a kernel thread. 258 */ 259 static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, 260 bool write, bool execute, bool foreign) 261 { 262 /* pkeys never affect instruction fetches */ 263 if (execute) 264 return true; 265 /* allow access if the VMA is not one from this process */ 266 if (foreign || vma_is_foreign(vma)) 267 return true; 268 return __pkru_allows_pkey(vma_pkey(vma), write); 269 } 270 271 unsigned long __get_current_cr3_fast(void); 272 273 #include <asm-generic/mmu_context.h> 274 275 #endif /* _ASM_X86_MMU_CONTEXT_H */ 276