1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_MMU_CONTEXT_H
3 #define _ASM_X86_MMU_CONTEXT_H
6 #include <linux/atomic.h>
7 #include <linux/mm_types.h>
8 #include <linux/pkeys.h>
10 #include <trace/events/tlb.h>
12 #include <asm/tlbflush.h>
13 #include <asm/paravirt.h>
14 #include <asm/debugreg.h>
15 #include <asm/gsseg.h>
17 extern atomic64_t last_mm_ctx_id;
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);
25 #ifdef CONFIG_MODIFY_LDT_SYSCALL
27 * ldt_structs can be allocated, used, and freed, but they are never
28 * modified while live.
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.
37 struct desc_struct *entries;
38 unsigned int nr_entries;
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.
47 * slot will be -1 if this LDT doesn't have an alias mapping.
53 * Used for LDT copy/destruction.
55 static inline void init_new_context_ldt(struct mm_struct *mm)
57 mm->context.ldt = NULL;
58 init_rwsem(&mm->context.ldt_usr_sem);
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,
70 static inline void destroy_context_ldt(struct mm_struct *mm) { }
71 static inline void ldt_arch_exit_mmap(struct mm_struct *mm) { }
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);
78 static inline void load_mm_ldt(struct mm_struct *mm)
82 static inline void switch_ldt(struct mm_struct *prev, struct mm_struct *next)
84 DEBUG_LOCKS_WARN_ON(preemptible());
88 #define enter_lazy_tlb enter_lazy_tlb
89 extern void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk);
92 * Init a new mm. Used on mm copies, like at fork()
93 * and on mm's that are brand-new, like at execve().
95 #define init_new_context init_new_context
96 static inline int init_new_context(struct task_struct *tsk,
99 mutex_init(&mm->context.lock);
101 mm->context.ctx_id = atomic64_inc_return(&last_mm_ctx_id);
102 atomic64_set(&mm->context.tlb_gen, 0);
104 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
105 if (cpu_feature_enabled(X86_FEATURE_OSPKE)) {
106 /* pkey 0 is the default and allocated implicitly */
107 mm->context.pkey_allocation_map = 0x1;
108 /* -1 means unallocated or invalid */
109 mm->context.execute_only_pkey = -1;
112 init_new_context_ldt(mm);
116 #define destroy_context destroy_context
117 static inline void destroy_context(struct mm_struct *mm)
119 destroy_context_ldt(mm);
122 extern void switch_mm(struct mm_struct *prev, struct mm_struct *next,
123 struct task_struct *tsk);
125 extern void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
126 struct task_struct *tsk);
127 #define switch_mm_irqs_off switch_mm_irqs_off
129 #define activate_mm(prev, next) \
131 paravirt_enter_mmap(next); \
132 switch_mm((prev), (next), NULL); \
136 #define deactivate_mm(tsk, mm) \
138 loadsegment(gs, 0); \
141 #define deactivate_mm(tsk, mm) \
144 loadsegment(fs, 0); \
148 static inline void arch_dup_pkeys(struct mm_struct *oldmm,
149 struct mm_struct *mm)
151 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
152 if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
155 /* Duplicate the oldmm pkey state in mm: */
156 mm->context.pkey_allocation_map = oldmm->context.pkey_allocation_map;
157 mm->context.execute_only_pkey = oldmm->context.execute_only_pkey;
161 static inline int arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
163 arch_dup_pkeys(oldmm, mm);
164 paravirt_enter_mmap(mm);
165 return ldt_dup_context(oldmm, mm);
168 static inline void arch_exit_mmap(struct mm_struct *mm)
170 paravirt_arch_exit_mmap(mm);
171 ldt_arch_exit_mmap(mm);
175 static inline bool is_64bit_mm(struct mm_struct *mm)
177 return !IS_ENABLED(CONFIG_IA32_EMULATION) ||
178 !(mm->context.flags & MM_CONTEXT_UPROBE_IA32);
181 static inline bool is_64bit_mm(struct mm_struct *mm)
187 static inline void arch_unmap(struct mm_struct *mm, unsigned long start,
193 * We only want to enforce protection keys on the current process
194 * because we effectively have no access to PKRU for other
195 * processes or any way to tell *which * PKRU in a threaded
196 * process we could use.
198 * So do not enforce things if the VMA is not from the current
199 * mm, or if we are in a kernel thread.
201 static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
202 bool write, bool execute, bool foreign)
204 /* pkeys never affect instruction fetches */
207 /* allow access if the VMA is not one from this process */
208 if (foreign || vma_is_foreign(vma))
210 return __pkru_allows_pkey(vma_pkey(vma), write);
213 unsigned long __get_current_cr3_fast(void);
215 #include <asm-generic/mmu_context.h>
217 #endif /* _ASM_X86_MMU_CONTEXT_H */