1b2441318SGreg Kroah-Hartman /* SPDX-License-Identifier: GPL-2.0 */
266d37570SDave Hansen #ifndef _ASM_X86_PKEYS_H
366d37570SDave Hansen #define _ASM_X86_PKEYS_H
466d37570SDave Hansen
516171bffSDave Hansen /*
616171bffSDave Hansen * If more than 16 keys are ever supported, a thorough audit
716171bffSDave Hansen * will be necessary to ensure that the types that store key
816171bffSDave Hansen * numbers and masks have sufficient capacity.
916171bffSDave Hansen */
10*8a1dc55aSThomas Gleixner #define arch_max_pkey() (cpu_feature_enabled(X86_FEATURE_OSPKE) ? 16 : 1)
1166d37570SDave Hansen
1284594296SDave Hansen extern int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
1384594296SDave Hansen unsigned long init_val);
1484594296SDave Hansen
arch_pkeys_enabled(void)153f36c942SMichael Ellerman static inline bool arch_pkeys_enabled(void)
163f36c942SMichael Ellerman {
17*8a1dc55aSThomas Gleixner return cpu_feature_enabled(X86_FEATURE_OSPKE);
183f36c942SMichael Ellerman }
193f36c942SMichael Ellerman
2062b5f7d0SDave Hansen /*
2162b5f7d0SDave Hansen * Try to dedicate one of the protection keys to be used as an
2262b5f7d0SDave Hansen * execute-only protection key.
2362b5f7d0SDave Hansen */
2462b5f7d0SDave Hansen extern int __execute_only_pkey(struct mm_struct *mm);
execute_only_pkey(struct mm_struct * mm)2562b5f7d0SDave Hansen static inline int execute_only_pkey(struct mm_struct *mm)
2662b5f7d0SDave Hansen {
27*8a1dc55aSThomas Gleixner if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
280a0b1520SDave Hansen return ARCH_DEFAULT_PKEY;
2962b5f7d0SDave Hansen
3062b5f7d0SDave Hansen return __execute_only_pkey(mm);
3162b5f7d0SDave Hansen }
3262b5f7d0SDave Hansen
3362b5f7d0SDave Hansen extern int __arch_override_mprotect_pkey(struct vm_area_struct *vma,
3462b5f7d0SDave Hansen int prot, int pkey);
arch_override_mprotect_pkey(struct vm_area_struct * vma,int prot,int pkey)3562b5f7d0SDave Hansen static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma,
3662b5f7d0SDave Hansen int prot, int pkey)
3762b5f7d0SDave Hansen {
38*8a1dc55aSThomas Gleixner if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
3962b5f7d0SDave Hansen return 0;
4062b5f7d0SDave Hansen
4162b5f7d0SDave Hansen return __arch_override_mprotect_pkey(vma, prot, pkey);
4262b5f7d0SDave Hansen }
4362b5f7d0SDave Hansen
44a8502b67SDave Hansen #define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | VM_PKEY_BIT3)
45a8502b67SDave Hansen
46e8c24d3aSDave Hansen #define mm_pkey_allocation_map(mm) (mm->context.pkey_allocation_map)
47e8c24d3aSDave Hansen #define mm_set_pkey_allocated(mm, pkey) do { \
48e8c24d3aSDave Hansen mm_pkey_allocation_map(mm) |= (1U << pkey); \
49e8c24d3aSDave Hansen } while (0)
50e8c24d3aSDave Hansen #define mm_set_pkey_free(mm, pkey) do { \
51e8c24d3aSDave Hansen mm_pkey_allocation_map(mm) &= ~(1U << pkey); \
52e8c24d3aSDave Hansen } while (0)
53e8c24d3aSDave Hansen
54e8c24d3aSDave Hansen static inline
mm_pkey_is_allocated(struct mm_struct * mm,int pkey)55e8c24d3aSDave Hansen bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey)
56e8c24d3aSDave Hansen {
5758ab9a08SDave Hansen /*
5858ab9a08SDave Hansen * "Allocated" pkeys are those that have been returned
592fa9d1cfSDave Hansen * from pkey_alloc() or pkey 0 which is allocated
602fa9d1cfSDave Hansen * implicitly when the mm is created.
6158ab9a08SDave Hansen */
622fa9d1cfSDave Hansen if (pkey < 0)
6358ab9a08SDave Hansen return false;
6458ab9a08SDave Hansen if (pkey >= arch_max_pkey())
6558ab9a08SDave Hansen return false;
660a0b1520SDave Hansen /*
670a0b1520SDave Hansen * The exec-only pkey is set in the allocation map, but
680a0b1520SDave Hansen * is not available to any of the user interfaces like
690a0b1520SDave Hansen * mprotect_pkey().
700a0b1520SDave Hansen */
710a0b1520SDave Hansen if (pkey == mm->context.execute_only_pkey)
720a0b1520SDave Hansen return false;
730a0b1520SDave Hansen
74e8c24d3aSDave Hansen return mm_pkey_allocation_map(mm) & (1U << pkey);
75e8c24d3aSDave Hansen }
76e8c24d3aSDave Hansen
77e8c24d3aSDave Hansen /*
78e8c24d3aSDave Hansen * Returns a positive, 4-bit key on success, or -1 on failure.
79e8c24d3aSDave Hansen */
80e8c24d3aSDave Hansen static inline
mm_pkey_alloc(struct mm_struct * mm)81e8c24d3aSDave Hansen int mm_pkey_alloc(struct mm_struct *mm)
82e8c24d3aSDave Hansen {
83e8c24d3aSDave Hansen /*
84e8c24d3aSDave Hansen * Note: this is the one and only place we make sure
85e8c24d3aSDave Hansen * that the pkey is valid as far as the hardware is
86e8c24d3aSDave Hansen * concerned. The rest of the kernel trusts that
87e8c24d3aSDave Hansen * only good, valid pkeys come out of here.
88e8c24d3aSDave Hansen */
89e8c24d3aSDave Hansen u16 all_pkeys_mask = ((1U << arch_max_pkey()) - 1);
90e8c24d3aSDave Hansen int ret;
91e8c24d3aSDave Hansen
92e8c24d3aSDave Hansen /*
93e8c24d3aSDave Hansen * Are we out of pkeys? We must handle this specially
94e8c24d3aSDave Hansen * because ffz() behavior is undefined if there are no
95e8c24d3aSDave Hansen * zeros.
96e8c24d3aSDave Hansen */
97e8c24d3aSDave Hansen if (mm_pkey_allocation_map(mm) == all_pkeys_mask)
98e8c24d3aSDave Hansen return -1;
99e8c24d3aSDave Hansen
100e8c24d3aSDave Hansen ret = ffz(mm_pkey_allocation_map(mm));
101e8c24d3aSDave Hansen
102e8c24d3aSDave Hansen mm_set_pkey_allocated(mm, ret);
103e8c24d3aSDave Hansen
104e8c24d3aSDave Hansen return ret;
105e8c24d3aSDave Hansen }
106e8c24d3aSDave Hansen
107e8c24d3aSDave Hansen static inline
mm_pkey_free(struct mm_struct * mm,int pkey)108e8c24d3aSDave Hansen int mm_pkey_free(struct mm_struct *mm, int pkey)
109e8c24d3aSDave Hansen {
110e8c24d3aSDave Hansen if (!mm_pkey_is_allocated(mm, pkey))
111e8c24d3aSDave Hansen return -EINVAL;
112e8c24d3aSDave Hansen
113e8c24d3aSDave Hansen mm_set_pkey_free(mm, pkey);
114e8c24d3aSDave Hansen
115e8c24d3aSDave Hansen return 0;
116e8c24d3aSDave Hansen }
117e8c24d3aSDave Hansen
vma_pkey(struct vm_area_struct * vma)118555934a7SMichael Ellerman static inline int vma_pkey(struct vm_area_struct *vma)
119555934a7SMichael Ellerman {
120555934a7SMichael Ellerman unsigned long vma_pkey_mask = VM_PKEY_BIT0 | VM_PKEY_BIT1 |
121555934a7SMichael Ellerman VM_PKEY_BIT2 | VM_PKEY_BIT3;
122555934a7SMichael Ellerman
123555934a7SMichael Ellerman return (vma->vm_flags & vma_pkey_mask) >> VM_PKEY_SHIFT;
124555934a7SMichael Ellerman }
125555934a7SMichael Ellerman
12666d37570SDave Hansen #endif /*_ASM_X86_PKEYS_H */
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