1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_PKEYS_H
3 #define _ASM_X86_PKEYS_H
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.
10 #define arch_max_pkey() (cpu_feature_enabled(X86_FEATURE_OSPKE) ? 16 : 1)
12 extern int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
13 unsigned long init_val);
15 static inline bool arch_pkeys_enabled(void)
17 return cpu_feature_enabled(X86_FEATURE_OSPKE);
21 * Try to dedicate one of the protection keys to be used as an
22 * execute-only protection key.
24 extern int __execute_only_pkey(struct mm_struct *mm);
25 static inline int execute_only_pkey(struct mm_struct *mm)
27 if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
28 return ARCH_DEFAULT_PKEY;
30 return __execute_only_pkey(mm);
33 extern int __arch_override_mprotect_pkey(struct vm_area_struct *vma,
35 static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma,
38 if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
41 return __arch_override_mprotect_pkey(vma, prot, pkey);
44 #define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | VM_PKEY_BIT3)
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); \
50 #define mm_set_pkey_free(mm, pkey) do { \
51 mm_pkey_allocation_map(mm) &= ~(1U << pkey); \
55 bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey)
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.
64 if (pkey >= arch_max_pkey())
67 * The exec-only pkey is set in the allocation map, but
68 * is not available to any of the user interfaces like
71 if (pkey == mm->context.execute_only_pkey)
74 return mm_pkey_allocation_map(mm) & (1U << pkey);
78 * Returns a positive, 4-bit key on success, or -1 on failure.
81 int mm_pkey_alloc(struct mm_struct *mm)
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.
89 u16 all_pkeys_mask = ((1U << arch_max_pkey()) - 1);
93 * Are we out of pkeys? We must handle this specially
94 * because ffz() behavior is undefined if there are no
97 if (mm_pkey_allocation_map(mm) == all_pkeys_mask)
100 ret = ffz(mm_pkey_allocation_map(mm));
102 mm_set_pkey_allocated(mm, ret);
108 int mm_pkey_free(struct mm_struct *mm, int pkey)
110 if (!mm_pkey_is_allocated(mm, pkey))
113 mm_set_pkey_free(mm, pkey);
118 static inline int vma_pkey(struct vm_area_struct *vma)
120 unsigned long vma_pkey_mask = VM_PKEY_BIT0 | VM_PKEY_BIT1 |
121 VM_PKEY_BIT2 | VM_PKEY_BIT3;
123 return (vma->vm_flags & vma_pkey_mask) >> VM_PKEY_SHIFT;
126 #endif /*_ASM_X86_PKEYS_H */