210 lines
5.8 KiB
C
Executable file
210 lines
5.8 KiB
C
Executable file
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* PowerPC Memory Protection Keys management
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*
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* Copyright 2017, Ram Pai, IBM Corporation.
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*/
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#ifndef _ASM_POWERPC_KEYS_H
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#define _ASM_POWERPC_KEYS_H
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#include <linux/jump_label.h>
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#include <asm/firmware.h>
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DECLARE_STATIC_KEY_TRUE(pkey_disabled);
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extern int pkeys_total; /* total pkeys as per device tree */
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extern u32 initial_allocation_mask; /* bits set for the initially allocated keys */
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extern u32 reserved_allocation_mask; /* bits set for reserved keys */
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#define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | \
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VM_PKEY_BIT3 | VM_PKEY_BIT4)
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/* Override any generic PKEY permission defines */
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#define PKEY_DISABLE_EXECUTE 0x4
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#define PKEY_ACCESS_MASK (PKEY_DISABLE_ACCESS | \
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PKEY_DISABLE_WRITE | \
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PKEY_DISABLE_EXECUTE)
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static inline u64 pkey_to_vmflag_bits(u16 pkey)
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{
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return (((u64)pkey << VM_PKEY_SHIFT) & ARCH_VM_PKEY_FLAGS);
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}
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static inline u64 vmflag_to_pte_pkey_bits(u64 vm_flags)
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{
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if (static_branch_likely(&pkey_disabled))
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return 0x0UL;
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return (((vm_flags & VM_PKEY_BIT0) ? H_PTE_PKEY_BIT4 : 0x0UL) |
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((vm_flags & VM_PKEY_BIT1) ? H_PTE_PKEY_BIT3 : 0x0UL) |
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((vm_flags & VM_PKEY_BIT2) ? H_PTE_PKEY_BIT2 : 0x0UL) |
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((vm_flags & VM_PKEY_BIT3) ? H_PTE_PKEY_BIT1 : 0x0UL) |
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((vm_flags & VM_PKEY_BIT4) ? H_PTE_PKEY_BIT0 : 0x0UL));
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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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if (static_branch_likely(&pkey_disabled))
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return 0;
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return (vma->vm_flags & ARCH_VM_PKEY_FLAGS) >> VM_PKEY_SHIFT;
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}
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#define arch_max_pkey() pkeys_total
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static inline u64 pte_to_hpte_pkey_bits(u64 pteflags)
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{
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return (((pteflags & H_PTE_PKEY_BIT0) ? HPTE_R_KEY_BIT0 : 0x0UL) |
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((pteflags & H_PTE_PKEY_BIT1) ? HPTE_R_KEY_BIT1 : 0x0UL) |
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((pteflags & H_PTE_PKEY_BIT2) ? HPTE_R_KEY_BIT2 : 0x0UL) |
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((pteflags & H_PTE_PKEY_BIT3) ? HPTE_R_KEY_BIT3 : 0x0UL) |
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((pteflags & H_PTE_PKEY_BIT4) ? HPTE_R_KEY_BIT4 : 0x0UL));
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}
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static inline u16 pte_to_pkey_bits(u64 pteflags)
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{
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return (((pteflags & H_PTE_PKEY_BIT0) ? 0x10 : 0x0UL) |
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((pteflags & H_PTE_PKEY_BIT1) ? 0x8 : 0x0UL) |
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((pteflags & H_PTE_PKEY_BIT2) ? 0x4 : 0x0UL) |
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((pteflags & H_PTE_PKEY_BIT3) ? 0x2 : 0x0UL) |
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((pteflags & H_PTE_PKEY_BIT4) ? 0x1 : 0x0UL));
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}
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#define pkey_alloc_mask(pkey) (0x1 << pkey)
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#define mm_pkey_allocation_map(mm) (mm->context.pkey_allocation_map)
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#define __mm_pkey_allocated(mm, pkey) { \
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mm_pkey_allocation_map(mm) |= pkey_alloc_mask(pkey); \
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}
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#define __mm_pkey_free(mm, pkey) { \
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mm_pkey_allocation_map(mm) &= ~pkey_alloc_mask(pkey); \
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}
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#define __mm_pkey_is_allocated(mm, pkey) \
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(mm_pkey_allocation_map(mm) & pkey_alloc_mask(pkey))
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#define __mm_pkey_is_reserved(pkey) (reserved_allocation_mask & \
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pkey_alloc_mask(pkey))
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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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if (pkey < 0 || pkey >= arch_max_pkey())
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return false;
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/* Reserved keys are never allocated. */
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if (__mm_pkey_is_reserved(pkey))
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return false;
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return __mm_pkey_is_allocated(mm, pkey);
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}
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/*
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* Returns a positive, 5-bit key on success, or -1 on failure.
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* Relies on the mmap_sem to protect against concurrency in mm_pkey_alloc() and
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* mm_pkey_free().
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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 that the pkey is
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* valid as far as the hardware is concerned. The rest of the kernel
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* trusts that only good, valid pkeys come out of here.
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*/
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u32 all_pkeys_mask = (u32)(~(0x0));
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int ret;
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if (static_branch_likely(&pkey_disabled))
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return -1;
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/*
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* Are we out of pkeys? We must handle this specially because ffz()
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* behavior is undefined if there are no 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((u32)mm_pkey_allocation_map(mm));
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__mm_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 (static_branch_likely(&pkey_disabled))
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return -1;
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if (!mm_pkey_is_allocated(mm, pkey))
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return -EINVAL;
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__mm_pkey_free(mm, pkey);
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return 0;
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}
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/*
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* Try to dedicate one of the protection keys to be used as an
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* execute-only protection key.
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*/
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extern int __execute_only_pkey(struct mm_struct *mm);
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static inline int execute_only_pkey(struct mm_struct *mm)
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{
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if (static_branch_likely(&pkey_disabled))
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return -1;
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return __execute_only_pkey(mm);
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}
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extern int __arch_override_mprotect_pkey(struct vm_area_struct *vma,
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int prot, int pkey);
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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 (static_branch_likely(&pkey_disabled))
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return 0;
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/*
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* Is this an mprotect_pkey() call? If so, never override the value that
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* came from the user.
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*/
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if (pkey != -1)
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return pkey;
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return __arch_override_mprotect_pkey(vma, prot, pkey);
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}
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extern 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 int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
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unsigned long init_val)
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{
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if (static_branch_likely(&pkey_disabled))
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return -EINVAL;
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/*
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* userspace should not change pkey-0 permissions.
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* pkey-0 is associated with every page in the kernel.
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* If userspace denies any permission on pkey-0, the
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* kernel cannot operate.
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*/
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if (pkey == 0)
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return init_val ? -EINVAL : 0;
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return __arch_set_user_pkey_access(tsk, pkey, init_val);
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}
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static inline bool arch_pkeys_enabled(void)
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{
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return !static_branch_likely(&pkey_disabled);
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}
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extern void pkey_mm_init(struct mm_struct *mm);
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extern bool arch_supports_pkeys(int cap);
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extern unsigned int arch_usable_pkeys(void);
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extern void thread_pkey_regs_save(struct thread_struct *thread);
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extern void thread_pkey_regs_restore(struct thread_struct *new_thread,
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struct thread_struct *old_thread);
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extern void thread_pkey_regs_init(struct thread_struct *thread);
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#endif /*_ASM_POWERPC_KEYS_H */
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