106 lines
2.4 KiB
C
106 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2023 Arm Ltd.
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*
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* Based on arch/x86/include/asm/pkeys.h
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*/
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#ifndef _ASM_ARM64_PKEYS_H
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#define _ASM_ARM64_PKEYS_H
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#define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2)
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#define arch_max_pkey() 8
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int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
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unsigned long init_val);
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static inline bool arch_pkeys_enabled(void)
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{
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return system_supports_poe();
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}
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static inline int vma_pkey(struct vm_area_struct *vma)
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{
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return (vma->vm_flags & ARCH_VM_PKEY_FLAGS) >> VM_PKEY_SHIFT;
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}
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static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma,
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int prot, int pkey)
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{
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if (pkey != -1)
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return pkey;
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return vma_pkey(vma);
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}
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static inline int execute_only_pkey(struct mm_struct *mm)
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{
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// Execute-only mappings are handled by EPAN/FEAT_PAN3.
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return -1;
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}
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#define mm_pkey_allocation_map(mm) (mm)->context.pkey_allocation_map
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#define mm_set_pkey_allocated(mm, pkey) do { \
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mm_pkey_allocation_map(mm) |= (1U << pkey); \
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} while (0)
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#define mm_set_pkey_free(mm, pkey) do { \
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mm_pkey_allocation_map(mm) &= ~(1U << pkey); \
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} while (0)
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static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey)
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{
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/*
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* "Allocated" pkeys are those that have been returned
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* from pkey_alloc() or pkey 0 which is allocated
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* implicitly when the mm is created.
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*/
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if (pkey < 0 || pkey >= arch_max_pkey())
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return false;
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return mm_pkey_allocation_map(mm) & (1U << pkey);
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}
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/*
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* Returns a positive, 3-bit key on success, or -1 on failure.
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*/
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static inline int mm_pkey_alloc(struct mm_struct *mm)
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{
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/*
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* Note: this is the one and only place we make sure
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* that the pkey is valid as far as the hardware is
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* concerned. The rest of the kernel trusts that
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* only good, valid pkeys come out of here.
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*/
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u8 all_pkeys_mask = GENMASK(arch_max_pkey() - 1, 0);
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int ret;
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if (!arch_pkeys_enabled())
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return -1;
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/*
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* Are we out of pkeys? We must handle this specially
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* because ffz() behavior is undefined if there are no
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* zeros.
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*/
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if (mm_pkey_allocation_map(mm) == all_pkeys_mask)
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return -1;
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ret = ffz(mm_pkey_allocation_map(mm));
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mm_set_pkey_allocated(mm, ret);
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return ret;
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}
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static inline int mm_pkey_free(struct mm_struct *mm, int pkey)
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{
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if (!mm_pkey_is_allocated(mm, pkey))
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return -EINVAL;
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mm_set_pkey_free(mm, pkey);
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return 0;
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}
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#endif /* _ASM_ARM64_PKEYS_H */
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