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 mm->context.next_trim_cpumask = jiffies + HZ; 155 156 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS 157 if (cpu_feature_enabled(X86_FEATURE_OSPKE)) { 158 /* pkey 0 is the default and allocated implicitly */ 159 mm->context.pkey_allocation_map = 0x1; 160 /* -1 means unallocated or invalid */ 161 mm->context.execute_only_pkey = -1; 162 } 163 #endif 164 mm_reset_untag_mask(mm); 165 init_new_context_ldt(mm); 166 return 0; 167 } 168 169 #define destroy_context destroy_context 170 static inline void destroy_context(struct mm_struct *mm) 171 { 172 destroy_context_ldt(mm); 173 } 174 175 extern void switch_mm(struct mm_struct *prev, struct mm_struct *next, 176 struct task_struct *tsk); 177 178 extern void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, 179 struct task_struct *tsk); 180 #define switch_mm_irqs_off switch_mm_irqs_off 181 182 #define activate_mm(prev, next) \ 183 do { \ 184 paravirt_enter_mmap(next); \ 185 switch_mm((prev), (next), NULL); \ 186 } while (0); 187 188 #ifdef CONFIG_X86_32 189 #define deactivate_mm(tsk, mm) \ 190 do { \ 191 loadsegment(gs, 0); \ 192 } while (0) 193 #else 194 #define deactivate_mm(tsk, mm) \ 195 do { \ 196 shstk_free(tsk); \ 197 load_gs_index(0); \ 198 loadsegment(fs, 0); \ 199 } while (0) 200 #endif 201 202 static inline void arch_dup_pkeys(struct mm_struct *oldmm, 203 struct mm_struct *mm) 204 { 205 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS 206 if (!cpu_feature_enabled(X86_FEATURE_OSPKE)) 207 return; 208 209 /* Duplicate the oldmm pkey state in mm: */ 210 mm->context.pkey_allocation_map = oldmm->context.pkey_allocation_map; 211 mm->context.execute_only_pkey = oldmm->context.execute_only_pkey; 212 #endif 213 } 214 215 static inline int arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm) 216 { 217 arch_dup_pkeys(oldmm, mm); 218 paravirt_enter_mmap(mm); 219 dup_lam(oldmm, mm); 220 return ldt_dup_context(oldmm, mm); 221 } 222 223 static inline void arch_exit_mmap(struct mm_struct *mm) 224 { 225 paravirt_arch_exit_mmap(mm); 226 ldt_arch_exit_mmap(mm); 227 } 228 229 #ifdef CONFIG_X86_64 230 static inline bool is_64bit_mm(struct mm_struct *mm) 231 { 232 return !IS_ENABLED(CONFIG_IA32_EMULATION) || 233 !test_bit(MM_CONTEXT_UPROBE_IA32, &mm->context.flags); 234 } 235 #else 236 static inline bool is_64bit_mm(struct mm_struct *mm) 237 { 238 return false; 239 } 240 #endif 241 242 /* 243 * We only want to enforce protection keys on the current process 244 * because we effectively have no access to PKRU for other 245 * processes or any way to tell *which * PKRU in a threaded 246 * process we could use. 247 * 248 * So do not enforce things if the VMA is not from the current 249 * mm, or if we are in a kernel thread. 250 */ 251 static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, 252 bool write, bool execute, bool foreign) 253 { 254 /* pkeys never affect instruction fetches */ 255 if (execute) 256 return true; 257 /* allow access if the VMA is not one from this process */ 258 if (foreign || vma_is_foreign(vma)) 259 return true; 260 return __pkru_allows_pkey(vma_pkey(vma), write); 261 } 262 263 unsigned long __get_current_cr3_fast(void); 264 265 #include <asm-generic/mmu_context.h> 266 267 #endif /* _ASM_X86_MMU_CONTEXT_H */ 268