1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _ASM_X86_PKEYS_H |
3 | #define _ASM_X86_PKEYS_H |
4 | |
5 | /* |
6 | * If more than 16 keys are ever supported, a thorough audit |
7 | * will be necessary to ensure that the types that store key |
8 | * numbers and masks have sufficient capacity. |
9 | */ |
10 | #define arch_max_pkey() (cpu_feature_enabled(X86_FEATURE_OSPKE) ? 16 : 1) |
11 | |
12 | extern int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, |
13 | unsigned long init_val); |
14 | |
15 | static inline bool arch_pkeys_enabled(void) |
16 | { |
17 | return cpu_feature_enabled(X86_FEATURE_OSPKE); |
18 | } |
19 | |
20 | /* |
21 | * Try to dedicate one of the protection keys to be used as an |
22 | * execute-only protection key. |
23 | */ |
24 | extern int __execute_only_pkey(struct mm_struct *mm); |
25 | static inline int execute_only_pkey(struct mm_struct *mm) |
26 | { |
27 | if (!cpu_feature_enabled(X86_FEATURE_OSPKE)) |
28 | return ARCH_DEFAULT_PKEY; |
29 | |
30 | return __execute_only_pkey(mm); |
31 | } |
32 | |
33 | extern int __arch_override_mprotect_pkey(struct vm_area_struct *vma, |
34 | int prot, int pkey); |
35 | static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma, |
36 | int prot, int pkey) |
37 | { |
38 | if (!cpu_feature_enabled(X86_FEATURE_OSPKE)) |
39 | return 0; |
40 | |
41 | return __arch_override_mprotect_pkey(vma, prot, pkey); |
42 | } |
43 | |
44 | #define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | VM_PKEY_BIT3) |
45 | |
46 | #define mm_pkey_allocation_map(mm) (mm->context.pkey_allocation_map) |
47 | #define mm_set_pkey_allocated(mm, pkey) do { \ |
48 | mm_pkey_allocation_map(mm) |= (1U << pkey); \ |
49 | } while (0) |
50 | #define mm_set_pkey_free(mm, pkey) do { \ |
51 | mm_pkey_allocation_map(mm) &= ~(1U << pkey); \ |
52 | } while (0) |
53 | |
54 | static inline |
55 | bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey) |
56 | { |
57 | /* |
58 | * "Allocated" pkeys are those that have been returned |
59 | * from pkey_alloc() or pkey 0 which is allocated |
60 | * implicitly when the mm is created. |
61 | */ |
62 | if (pkey < 0) |
63 | return false; |
64 | if (pkey >= arch_max_pkey()) |
65 | return false; |
66 | /* |
67 | * The exec-only pkey is set in the allocation map, but |
68 | * is not available to any of the user interfaces like |
69 | * mprotect_pkey(). |
70 | */ |
71 | if (pkey == mm->context.execute_only_pkey) |
72 | return false; |
73 | |
74 | return mm_pkey_allocation_map(mm) & (1U << pkey); |
75 | } |
76 | |
77 | /* |
78 | * Returns a positive, 4-bit key on success, or -1 on failure. |
79 | */ |
80 | static inline |
81 | int mm_pkey_alloc(struct mm_struct *mm) |
82 | { |
83 | /* |
84 | * Note: this is the one and only place we make sure |
85 | * that the pkey is valid as far as the hardware is |
86 | * concerned. The rest of the kernel trusts that |
87 | * only good, valid pkeys come out of here. |
88 | */ |
89 | u16 all_pkeys_mask = ((1U << arch_max_pkey()) - 1); |
90 | int ret; |
91 | |
92 | /* |
93 | * Are we out of pkeys? We must handle this specially |
94 | * because ffz() behavior is undefined if there are no |
95 | * zeros. |
96 | */ |
97 | if (mm_pkey_allocation_map(mm) == all_pkeys_mask) |
98 | return -1; |
99 | |
100 | ret = ffz(mm_pkey_allocation_map(mm)); |
101 | |
102 | mm_set_pkey_allocated(mm, ret); |
103 | |
104 | return ret; |
105 | } |
106 | |
107 | static inline |
108 | int mm_pkey_free(struct mm_struct *mm, int pkey) |
109 | { |
110 | if (!mm_pkey_is_allocated(mm, pkey)) |
111 | return -EINVAL; |
112 | |
113 | mm_set_pkey_free(mm, pkey); |
114 | |
115 | return 0; |
116 | } |
117 | |
118 | static inline int vma_pkey(struct vm_area_struct *vma) |
119 | { |
120 | unsigned long vma_pkey_mask = VM_PKEY_BIT0 | VM_PKEY_BIT1 | |
121 | VM_PKEY_BIT2 | VM_PKEY_BIT3; |
122 | |
123 | return (vma->vm_flags & vma_pkey_mask) >> VM_PKEY_SHIFT; |
124 | } |
125 | |
126 | #endif /*_ASM_X86_PKEYS_H */ |
127 | |