1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_X86_PKEYS_H 3 #define _ASM_X86_PKEYS_H 4 5 #define arch_max_pkey() (boot_cpu_has(X86_FEATURE_OSPKE) ? 16 : 1) 6 7 extern int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, 8 unsigned long init_val); 9 10 /* 11 * Try to dedicate one of the protection keys to be used as an 12 * execute-only protection key. 13 */ 14 extern int __execute_only_pkey(struct mm_struct *mm); 15 static inline int execute_only_pkey(struct mm_struct *mm) 16 { 17 if (!boot_cpu_has(X86_FEATURE_OSPKE)) 18 return 0; 19 20 return __execute_only_pkey(mm); 21 } 22 23 extern int __arch_override_mprotect_pkey(struct vm_area_struct *vma, 24 int prot, int pkey); 25 static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma, 26 int prot, int pkey) 27 { 28 if (!boot_cpu_has(X86_FEATURE_OSPKE)) 29 return 0; 30 31 return __arch_override_mprotect_pkey(vma, prot, pkey); 32 } 33 34 extern int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, 35 unsigned long init_val); 36 37 #define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | VM_PKEY_BIT3) 38 39 #define mm_pkey_allocation_map(mm) (mm->context.pkey_allocation_map) 40 #define mm_set_pkey_allocated(mm, pkey) do { \ 41 mm_pkey_allocation_map(mm) |= (1U << pkey); \ 42 } while (0) 43 #define mm_set_pkey_free(mm, pkey) do { \ 44 mm_pkey_allocation_map(mm) &= ~(1U << pkey); \ 45 } while (0) 46 47 static inline 48 bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey) 49 { 50 /* 51 * "Allocated" pkeys are those that have been returned 52 * from pkey_alloc(). pkey 0 is special, and never 53 * returned from pkey_alloc(). 54 */ 55 if (pkey <= 0) 56 return false; 57 if (pkey >= arch_max_pkey()) 58 return false; 59 return mm_pkey_allocation_map(mm) & (1U << pkey); 60 } 61 62 /* 63 * Returns a positive, 4-bit key on success, or -1 on failure. 64 */ 65 static inline 66 int mm_pkey_alloc(struct mm_struct *mm) 67 { 68 /* 69 * Note: this is the one and only place we make sure 70 * that the pkey is valid as far as the hardware is 71 * concerned. The rest of the kernel trusts that 72 * only good, valid pkeys come out of here. 73 */ 74 u16 all_pkeys_mask = ((1U << arch_max_pkey()) - 1); 75 int ret; 76 77 /* 78 * Are we out of pkeys? We must handle this specially 79 * because ffz() behavior is undefined if there are no 80 * zeros. 81 */ 82 if (mm_pkey_allocation_map(mm) == all_pkeys_mask) 83 return -1; 84 85 ret = ffz(mm_pkey_allocation_map(mm)); 86 87 mm_set_pkey_allocated(mm, ret); 88 89 return ret; 90 } 91 92 static inline 93 int mm_pkey_free(struct mm_struct *mm, int pkey) 94 { 95 if (!mm_pkey_is_allocated(mm, pkey)) 96 return -EINVAL; 97 98 mm_set_pkey_free(mm, pkey); 99 100 return 0; 101 } 102 103 extern int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, 104 unsigned long init_val); 105 extern int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, 106 unsigned long init_val); 107 extern void copy_init_pkru_to_fpregs(void); 108 109 #endif /*_ASM_X86_PKEYS_H */ 110