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