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 17extern atomic64_t last_mm_ctx_id; 18 19#ifdef CONFIG_PERF_EVENTS 20DECLARE_STATIC_KEY_FALSE(rdpmc_never_available_key); 21DECLARE_STATIC_KEY_FALSE(rdpmc_always_available_key); 22void 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 */ 30struct 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 */ 55static 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} 60int ldt_dup_context(struct mm_struct *oldmm, struct mm_struct *mm); 61void destroy_context_ldt(struct mm_struct *mm); 62void ldt_arch_exit_mmap(struct mm_struct *mm); 63#else /* CONFIG_MODIFY_LDT_SYSCALL */ 64static inline void init_new_context_ldt(struct mm_struct *mm) { } 65static inline int ldt_dup_context(struct mm_struct *oldmm, 66 struct mm_struct *mm) 67{ 68 return 0; 69} 70static inline void destroy_context_ldt(struct mm_struct *mm) { } 71static inline void ldt_arch_exit_mmap(struct mm_struct *mm) { } 72#endif 73 74#ifdef CONFIG_MODIFY_LDT_SYSCALL 75extern void load_mm_ldt(struct mm_struct *mm); 76extern void switch_ldt(struct mm_struct *prev, struct mm_struct *next); 77#else 78static inline void load_mm_ldt(struct mm_struct *mm) 79{ 80 clear_LDT(); 81} 82static 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 89static inline unsigned long mm_lam_cr3_mask(struct mm_struct *mm) 90{ 91 return mm->context.lam_cr3_mask; 92} 93 94static 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 101static inline unsigned long mm_untag_mask(struct mm_struct *mm) 102{ 103 return mm->context.untag_mask; 104} 105 106static 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 112static 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 119static inline unsigned long mm_lam_cr3_mask(struct mm_struct *mm) 120{ 121 return 0; 122} 123 124static inline void dup_lam(struct mm_struct *oldmm, struct mm_struct *mm) 125{ 126} 127 128static inline void mm_reset_untag_mask(struct mm_struct *mm) 129{ 130} 131#endif 132 133#define enter_lazy_tlb enter_lazy_tlb 134extern 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 141static 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 163static inline void destroy_context(struct mm_struct *mm) 164{ 165 destroy_context_ldt(mm); 166} 167 168extern void switch_mm(struct mm_struct *prev, struct mm_struct *next, 169 struct task_struct *tsk); 170 171extern 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) \ 176do { \ 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) \ 183do { \ 184 loadsegment(gs, 0); \ 185} while (0) 186#else 187#define deactivate_mm(tsk, mm) \ 188do { \ 189 shstk_free(tsk); \ 190 load_gs_index(0); \ 191 loadsegment(fs, 0); \ 192} while (0) 193#endif 194 195static 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 208static 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 216static 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 223static 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 229static inline bool is_64bit_mm(struct mm_struct *mm) 230{ 231 return false; 232} 233#endif 234 235static 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 */ 249static 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 261unsigned long __get_current_cr3_fast(void); 262 263#include <asm-generic/mmu_context.h> 264 265#endif /* _ASM_X86_MMU_CONTEXT_H */ 266