arch/x86/include/asm/pkeys.h

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