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