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
16extern atomic64_t last_mm_ctx_id;
17
18#ifndef CONFIG_PARAVIRT_XXL
19static 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
26DECLARE_STATIC_KEY_FALSE(rdpmc_never_available_key);
27DECLARE_STATIC_KEY_FALSE(rdpmc_always_available_key);
28void 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 */
36struct 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 */
61static 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}
66int ldt_dup_context(struct mm_struct *oldmm, struct mm_struct *mm);
67void destroy_context_ldt(struct mm_struct *mm);
68void ldt_arch_exit_mmap(struct mm_struct *mm);
69#else /* CONFIG_MODIFY_LDT_SYSCALL */
70static inline void init_new_context_ldt(struct mm_struct *mm) { }
71static inline int ldt_dup_context(struct mm_struct *oldmm,
72 struct mm_struct *mm)
73{
74 return 0;
75}
76static inline void destroy_context_ldt(struct mm_struct *mm) { }
77static inline void ldt_arch_exit_mmap(struct mm_struct *mm) { }
78#endif
79
80#ifdef CONFIG_MODIFY_LDT_SYSCALL
81extern void load_mm_ldt(struct mm_struct *mm);
82extern void switch_ldt(struct mm_struct *prev, struct mm_struct *next);
83#else
84static inline void load_mm_ldt(struct mm_struct *mm)
85{
86 clear_LDT();
87}
88static 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
95extern 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
102static 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
123static inline void destroy_context(struct mm_struct *mm)
124{
125 destroy_context_ldt(mm);
126}
127
128extern void switch_mm(struct mm_struct *prev, struct mm_struct *next,
129 struct task_struct *tsk);
130
131extern 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) \
136do { \
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) \
143do { \
144 loadsegment(gs, 0); \
145} while (0)
146#else
147#define deactivate_mm(tsk, mm) \
148do { \
149 load_gs_index(0); \
150 loadsegment(fs, 0); \
151} while (0)
152#endif
153
154static 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
167static 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
174static 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
181static 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
187static inline bool is_64bit_mm(struct mm_struct *mm)
188{
189 return false;
190}
191#endif
192
193static 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 */
207static 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
219unsigned long __get_current_cr3_fast(void);
220
221#include <asm-generic/mmu_context.h>
222
223#endif /* _ASM_X86_MMU_CONTEXT_H */
224

source code of linux/arch/x86/include/asm/mmu_context.h