218 lines
5.7 KiB
C
218 lines
5.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_MMU_CONTEXT_H
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#define _ASM_X86_MMU_CONTEXT_H
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#include <asm/desc.h>
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#include <linux/atomic.h>
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#include <linux/mm_types.h>
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#include <linux/pkeys.h>
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#include <trace/events/tlb.h>
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#include <asm/tlbflush.h>
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#include <asm/paravirt.h>
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#include <asm/debugreg.h>
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extern atomic64_t last_mm_ctx_id;
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#ifndef CONFIG_PARAVIRT_XXL
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static inline void paravirt_activate_mm(struct mm_struct *prev,
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struct mm_struct *next)
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{
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}
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#endif /* !CONFIG_PARAVIRT_XXL */
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#ifdef CONFIG_PERF_EVENTS
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DECLARE_STATIC_KEY_FALSE(rdpmc_never_available_key);
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DECLARE_STATIC_KEY_FALSE(rdpmc_always_available_key);
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void cr4_update_pce(void *ignored);
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#endif
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#ifdef CONFIG_MODIFY_LDT_SYSCALL
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/*
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* ldt_structs can be allocated, used, and freed, but they are never
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* modified while live.
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*/
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struct ldt_struct {
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/*
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* Xen requires page-aligned LDTs with special permissions. This is
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* needed to prevent us from installing evil descriptors such as
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* call gates. On native, we could merge the ldt_struct and LDT
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* allocations, but it's not worth trying to optimize.
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*/
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struct desc_struct *entries;
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unsigned int nr_entries;
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/*
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* If PTI is in use, then the entries array is not mapped while we're
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* in user mode. The whole array will be aliased at the addressed
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* given by ldt_slot_va(slot). We use two slots so that we can allocate
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* and map, and enable a new LDT without invalidating the mapping
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* of an older, still-in-use LDT.
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*
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* slot will be -1 if this LDT doesn't have an alias mapping.
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*/
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int slot;
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};
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/*
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* Used for LDT copy/destruction.
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*/
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static inline void init_new_context_ldt(struct mm_struct *mm)
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{
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mm->context.ldt = NULL;
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init_rwsem(&mm->context.ldt_usr_sem);
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}
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int ldt_dup_context(struct mm_struct *oldmm, struct mm_struct *mm);
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void destroy_context_ldt(struct mm_struct *mm);
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void ldt_arch_exit_mmap(struct mm_struct *mm);
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#else /* CONFIG_MODIFY_LDT_SYSCALL */
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static inline void init_new_context_ldt(struct mm_struct *mm) { }
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static inline int ldt_dup_context(struct mm_struct *oldmm,
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struct mm_struct *mm)
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{
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return 0;
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}
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static inline void destroy_context_ldt(struct mm_struct *mm) { }
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static inline void ldt_arch_exit_mmap(struct mm_struct *mm) { }
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#endif
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#ifdef CONFIG_MODIFY_LDT_SYSCALL
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extern void load_mm_ldt(struct mm_struct *mm);
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extern void switch_ldt(struct mm_struct *prev, struct mm_struct *next);
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#else
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static inline void load_mm_ldt(struct mm_struct *mm)
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{
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clear_LDT();
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}
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static inline void switch_ldt(struct mm_struct *prev, struct mm_struct *next)
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{
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DEBUG_LOCKS_WARN_ON(preemptible());
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}
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#endif
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extern void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk);
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/*
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* Init a new mm. Used on mm copies, like at fork()
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* and on mm's that are brand-new, like at execve().
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*/
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static inline int init_new_context(struct task_struct *tsk,
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struct mm_struct *mm)
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{
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mutex_init(&mm->context.lock);
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mm->context.ctx_id = atomic64_inc_return(&last_mm_ctx_id);
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atomic64_set(&mm->context.tlb_gen, 0);
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#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
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if (cpu_feature_enabled(X86_FEATURE_OSPKE)) {
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/* pkey 0 is the default and allocated implicitly */
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mm->context.pkey_allocation_map = 0x1;
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/* -1 means unallocated or invalid */
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mm->context.execute_only_pkey = -1;
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}
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#endif
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init_new_context_ldt(mm);
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return 0;
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}
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static inline void destroy_context(struct mm_struct *mm)
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{
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destroy_context_ldt(mm);
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}
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extern void switch_mm(struct mm_struct *prev, struct mm_struct *next,
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struct task_struct *tsk);
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extern void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
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struct task_struct *tsk);
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#define switch_mm_irqs_off switch_mm_irqs_off
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#define activate_mm(prev, next) \
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do { \
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paravirt_activate_mm((prev), (next)); \
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switch_mm((prev), (next), NULL); \
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} while (0);
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#ifdef CONFIG_X86_32
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#define deactivate_mm(tsk, mm) \
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do { \
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lazy_load_gs(0); \
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} while (0)
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#else
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#define deactivate_mm(tsk, mm) \
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do { \
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load_gs_index(0); \
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loadsegment(fs, 0); \
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} while (0)
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#endif
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static inline void arch_dup_pkeys(struct mm_struct *oldmm,
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struct mm_struct *mm)
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{
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#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
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if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
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return;
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/* Duplicate the oldmm pkey state in mm: */
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mm->context.pkey_allocation_map = oldmm->context.pkey_allocation_map;
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mm->context.execute_only_pkey = oldmm->context.execute_only_pkey;
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#endif
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}
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static inline int arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
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{
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arch_dup_pkeys(oldmm, mm);
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paravirt_arch_dup_mmap(oldmm, mm);
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return ldt_dup_context(oldmm, mm);
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}
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static inline void arch_exit_mmap(struct mm_struct *mm)
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{
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paravirt_arch_exit_mmap(mm);
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ldt_arch_exit_mmap(mm);
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}
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#ifdef CONFIG_X86_64
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static inline bool is_64bit_mm(struct mm_struct *mm)
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{
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return !IS_ENABLED(CONFIG_IA32_EMULATION) ||
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!(mm->context.flags & MM_CONTEXT_UPROBE_IA32);
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}
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#else
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static inline bool is_64bit_mm(struct mm_struct *mm)
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{
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return false;
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}
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#endif
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static inline void arch_unmap(struct mm_struct *mm, unsigned long start,
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unsigned long end)
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{
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}
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/*
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* We only want to enforce protection keys on the current process
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* because we effectively have no access to PKRU for other
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* processes or any way to tell *which * PKRU in a threaded
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* process we could use.
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*
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* So do not enforce things if the VMA is not from the current
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* mm, or if we are in a kernel thread.
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*/
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static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
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bool write, bool execute, bool foreign)
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{
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/* pkeys never affect instruction fetches */
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if (execute)
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return true;
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/* allow access if the VMA is not one from this process */
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if (foreign || vma_is_foreign(vma))
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return true;
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return __pkru_allows_pkey(vma_pkey(vma), write);
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}
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unsigned long __get_current_cr3_fast(void);
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#endif /* _ASM_X86_MMU_CONTEXT_H */
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