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