cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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pkeys.h (3210B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2#ifndef _ASM_X86_PKEYS_H
      3#define _ASM_X86_PKEYS_H
      4
      5/*
      6 * If more than 16 keys are ever supported, a thorough audit
      7 * will be necessary to ensure that the types that store key
      8 * numbers and masks have sufficient capacity.
      9 */
     10#define arch_max_pkey() (cpu_feature_enabled(X86_FEATURE_OSPKE) ? 16 : 1)
     11
     12extern int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
     13		unsigned long init_val);
     14
     15static inline bool arch_pkeys_enabled(void)
     16{
     17	return cpu_feature_enabled(X86_FEATURE_OSPKE);
     18}
     19
     20/*
     21 * Try to dedicate one of the protection keys to be used as an
     22 * execute-only protection key.
     23 */
     24extern int __execute_only_pkey(struct mm_struct *mm);
     25static inline int execute_only_pkey(struct mm_struct *mm)
     26{
     27	if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
     28		return ARCH_DEFAULT_PKEY;
     29
     30	return __execute_only_pkey(mm);
     31}
     32
     33extern int __arch_override_mprotect_pkey(struct vm_area_struct *vma,
     34		int prot, int pkey);
     35static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma,
     36		int prot, int pkey)
     37{
     38	if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
     39		return 0;
     40
     41	return __arch_override_mprotect_pkey(vma, prot, pkey);
     42}
     43
     44#define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | VM_PKEY_BIT3)
     45
     46#define mm_pkey_allocation_map(mm)	(mm->context.pkey_allocation_map)
     47#define mm_set_pkey_allocated(mm, pkey) do {		\
     48	mm_pkey_allocation_map(mm) |= (1U << pkey);	\
     49} while (0)
     50#define mm_set_pkey_free(mm, pkey) do {			\
     51	mm_pkey_allocation_map(mm) &= ~(1U << pkey);	\
     52} while (0)
     53
     54static inline
     55bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey)
     56{
     57	/*
     58	 * "Allocated" pkeys are those that have been returned
     59	 * from pkey_alloc() or pkey 0 which is allocated
     60	 * implicitly when the mm is created.
     61	 */
     62	if (pkey < 0)
     63		return false;
     64	if (pkey >= arch_max_pkey())
     65		return false;
     66	/*
     67	 * The exec-only pkey is set in the allocation map, but
     68	 * is not available to any of the user interfaces like
     69	 * mprotect_pkey().
     70	 */
     71	if (pkey == mm->context.execute_only_pkey)
     72		return false;
     73
     74	return mm_pkey_allocation_map(mm) & (1U << pkey);
     75}
     76
     77/*
     78 * Returns a positive, 4-bit key on success, or -1 on failure.
     79 */
     80static inline
     81int mm_pkey_alloc(struct mm_struct *mm)
     82{
     83	/*
     84	 * Note: this is the one and only place we make sure
     85	 * that the pkey is valid as far as the hardware is
     86	 * concerned.  The rest of the kernel trusts that
     87	 * only good, valid pkeys come out of here.
     88	 */
     89	u16 all_pkeys_mask = ((1U << arch_max_pkey()) - 1);
     90	int ret;
     91
     92	/*
     93	 * Are we out of pkeys?  We must handle this specially
     94	 * because ffz() behavior is undefined if there are no
     95	 * zeros.
     96	 */
     97	if (mm_pkey_allocation_map(mm) == all_pkeys_mask)
     98		return -1;
     99
    100	ret = ffz(mm_pkey_allocation_map(mm));
    101
    102	mm_set_pkey_allocated(mm, ret);
    103
    104	return ret;
    105}
    106
    107static inline
    108int mm_pkey_free(struct mm_struct *mm, int pkey)
    109{
    110	if (!mm_pkey_is_allocated(mm, pkey))
    111		return -EINVAL;
    112
    113	mm_set_pkey_free(mm, pkey);
    114
    115	return 0;
    116}
    117
    118static inline int vma_pkey(struct vm_area_struct *vma)
    119{
    120	unsigned long vma_pkey_mask = VM_PKEY_BIT0 | VM_PKEY_BIT1 |
    121				      VM_PKEY_BIT2 | VM_PKEY_BIT3;
    122
    123	return (vma->vm_flags & vma_pkey_mask) >> VM_PKEY_SHIFT;
    124}
    125
    126#endif /*_ASM_X86_PKEYS_H */