arch/x86/include/asm/pkeys.h

   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 */