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 return mm->context.lam_cr3_mask;
92 }
93
94 static 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
101 static inline unsigned long mm_untag_mask(struct mm_struct *mm)
102 {
103 return mm->context.untag_mask;
104 }
105
106 static 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
112 static 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
119 static inline unsigned long mm_lam_cr3_mask(struct mm_struct *mm)
120 {
121 return 0;
122 }
123
124 static inline void dup_lam(struct mm_struct *oldmm, struct mm_struct *mm)
125 {
126 }
127
128 static inline void mm_reset_untag_mask(struct mm_struct *mm)
129 {
130 }
131 #endif
132
133 #define enter_lazy_tlb enter_lazy_tlb
134 extern 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
141 static 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
163 static inline void destroy_context(struct mm_struct *mm)
164 {
165 destroy_context_ldt(mm);
166 }
167
168 extern void switch_mm(struct mm_struct *prev, struct mm_struct *next,
169 struct task_struct *tsk);
170
171 extern 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) \
176 do { \
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) \
183 do { \
184 loadsegment(gs, 0); \
185 } while (0)
186 #else
187 #define deactivate_mm(tsk, mm) \
188 do { \
189 shstk_free(tsk); \
190 load_gs_index(0); \
191 loadsegment(fs, 0); \
192 } while (0)
193 #endif
194
195 static 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
208 static 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
216 static 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
223 static 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
229 static inline bool is_64bit_mm(struct mm_struct *mm)
230 {
231 return false;
232 }
233 #endif
234
235 static 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 */
249 static 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
261 unsigned long __get_current_cr3_fast(void);
262
263 #include <asm-generic/mmu_context.h>
264
265 #endif /* _ASM_X86_MMU_CONTEXT_H */
266
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