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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>
DECLARE_STATIC_KEY_TRUE(pkey_disabled);
extern int pkeys_total; /* total pkeys as per device tree */
extern u32 initial_allocation_mask; /* bits set for reserved keys */
/*
* Define these here temporarily so we're not dependent on patching linux/mm.h.
* Once it's updated we can drop these.
*/
#ifndef VM_PKEY_BIT0
# define VM_PKEY_SHIFT VM_HIGH_ARCH_BIT_0
# define VM_PKEY_BIT0 VM_HIGH_ARCH_0
# define VM_PKEY_BIT1 VM_HIGH_ARCH_1
# define VM_PKEY_BIT2 VM_HIGH_ARCH_2
# define VM_PKEY_BIT3 VM_HIGH_ARCH_3
# define VM_PKEY_BIT4 VM_HIGH_ARCH_4
#endif
#define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | \
VM_PKEY_BIT3 | VM_PKEY_BIT4)
#define arch_max_pkey() pkeys_total
#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) (initial_allocation_mask & \
pkey_alloc_mask(pkey))
static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey)
{
/* A reserved key is never considered as 'explicitly allocated' */
return ((pkey < arch_max_pkey()) &&
!__mm_pkey_is_reserved(pkey) &&
__mm_pkey_is_allocated(mm, pkey));
}
extern void __arch_activate_pkey(int pkey);
extern void __arch_deactivate_pkey(int 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);
/*
* Enable the key in the hardware
*/
if (ret > 0)
__arch_activate_pkey(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;
/*
* Disable the key in the hardware
*/
__arch_deactivate_pkey(pkey);
__mm_pkey_free(mm, pkey);
return 0;
}
/*
* Try to dedicate one of the protection keys to be used as an
* execute-only protection key.
*/
static inline int execute_only_pkey(struct mm_struct *mm)
{
return 0;
}
static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma,
int prot, int pkey)
{
return 0;
}
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;
return __arch_set_user_pkey_access(tsk, pkey, init_val);
}
extern void pkey_mm_init(struct mm_struct *mm);
#endif /*_ASM_POWERPC_KEYS_H */
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