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 /* 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 /* 143 * Init a new mm. Used on mm copies, like at fork() 144 * and on mm's that are brand-new, like at execve(). 145 */ 146 #define init_new_context init_new_context 147 static inline int init_new_context(struct task_struct *tsk, 148 struct mm_struct *mm) 149 { 150 mutex_init(&mm->context.lock); 151 152 mm->context.ctx_id = atomic64_inc_return(&last_mm_ctx_id); 153 atomic64_set(&mm->context.tlb_gen, 0); 154 155 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS 156 if (cpu_feature_enabled(X86_FEATURE_OSPKE)) { 157 /* pkey 0 is the default and allocated implicitly */ 158 mm->context.pkey_allocation_map = 0x1; 159 /* -1 means unallocated or invalid */ 160 mm->context.execute_only_pkey = -1; 161 } 162 #endif 163 mm_reset_untag_mask(mm); 164 init_new_context_ldt(mm); 165 return 0; 166 } 167 168 #define destroy_context destroy_context 169 static inline void destroy_context(struct mm_struct *mm) 170 { 171 destroy_context_ldt(mm); 172 } 173 174 extern void switch_mm(struct mm_struct *prev, struct mm_struct *next, 175 struct task_struct *tsk); 176 177 extern void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, 178 struct task_struct *tsk); 179 #define switch_mm_irqs_off switch_mm_irqs_off 180 181 #define activate_mm(prev, next) \ 182 do { \ 183 paravirt_enter_mmap(next); \ 184 switch_mm((prev), (next), NULL); \ 185 } while (0); 186 187 #ifdef CONFIG_X86_32 188 #define deactivate_mm(tsk, mm) \ 189 do { \ 190 loadsegment(gs, 0); \ 191 } while (0) 192 #else 193 #define deactivate_mm(tsk, mm) \ 194 do { \ 195 shstk_free(tsk); \ 196 load_gs_index(0); \ 197 loadsegment(fs, 0); \ 198 } while (0) 199 #endif 200 201 static inline void arch_dup_pkeys(struct mm_struct *oldmm, 202 struct mm_struct *mm) 203 { 204 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS 205 if (!cpu_feature_enabled(X86_FEATURE_OSPKE)) 206 return; 207 208 /* Duplicate the oldmm pkey state in mm: */ 209 mm->context.pkey_allocation_map = oldmm->context.pkey_allocation_map; 210 mm->context.execute_only_pkey = oldmm->context.execute_only_pkey; 211 #endif 212 } 213 214 static inline int arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) 215 { 216 arch_dup_pkeys(oldmm, mm); 217 paravirt_enter_mmap(mm); 218 dup_lam(oldmm, mm); 219 return ldt_dup_context(oldmm, mm); 220 } 221 222 static inline void arch_exit_mmap(struct mm_struct *mm) 223 { 224 paravirt_arch_exit_mmap(mm); 225 ldt_arch_exit_mmap(mm); 226 } 227 228 #ifdef CONFIG_X86_64 229 static inline bool is_64bit_mm(struct mm_struct *mm) 230 { 231 return !IS_ENABLED(CONFIG_IA32_EMULATION) || 232 !test_bit(MM_CONTEXT_UPROBE_IA32, &mm->context.flags); 233 } 234 #else 235 static inline bool is_64bit_mm(struct mm_struct *mm) 236 { 237 return false; 238 } 239 #endif 240 241 /* 242 * We only want to enforce protection keys on the current process 243 * because we effectively have no access to PKRU for other 244 * processes or any way to tell *which * PKRU in a threaded 245 * process we could use. 246 * 247 * So do not enforce things if the VMA is not from the current 248 * mm, or if we are in a kernel thread. 249 */ 250 static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, 251 bool write, bool execute, bool foreign) 252 { 253 /* pkeys never affect instruction fetches */ 254 if (execute) 255 return true; 256 /* allow access if the VMA is not one from this process */ 257 if (foreign || vma_is_foreign(vma)) 258 return true; 259 return __pkru_allows_pkey(vma_pkey(vma), write); 260 } 261 262 unsigned long __get_current_cr3_fast(void); 263 264 #include <asm-generic/mmu_context.h> 265 266 #endif /* _ASM_X86_MMU_CONTEXT_H */ 267