 64e455079e
			
		
	
	
	64e455079e
	
	
	
		
			
			For VMAs that don't want write notifications, PTEs created for read faults
have their write bit set.  If the read fault happens after VM_SOFTDIRTY is
cleared, then the PTE's softdirty bit will remain clear after subsequent
writes.
Here's a simple code snippet to demonstrate the bug:
  char* m = mmap(NULL, getpagesize(), PROT_READ | PROT_WRITE,
                 MAP_ANONYMOUS | MAP_SHARED, -1, 0);
  system("echo 4 > /proc/$PPID/clear_refs"); /* clear VM_SOFTDIRTY */
  assert(*m == '\0');     /* new PTE allows write access */
  assert(!soft_dirty(x));
  *m = 'x';               /* should dirty the page */
  assert(soft_dirty(x));  /* fails */
With this patch, write notifications are enabled when VM_SOFTDIRTY is
cleared.  Furthermore, to avoid unnecessary faults, write notifications
are disabled when VM_SOFTDIRTY is set.
As a side effect of enabling and disabling write notifications with
care, this patch fixes a bug in mprotect where vm_page_prot bits set by
drivers were zapped on mprotect.  An analogous bug was fixed in mmap by
commit c9d0bf2414 ("mm: uncached vma support with writenotify").
Signed-off-by: Peter Feiner <pfeiner@google.com>
Reported-by: Peter Feiner <pfeiner@google.com>
Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Jamie Liu <jamieliu@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
		
	
			
		
			
				
	
	
		
			839 lines
		
	
	
	
		
			22 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			839 lines
		
	
	
	
		
			22 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
| #ifndef _ASM_GENERIC_PGTABLE_H
 | |
| #define _ASM_GENERIC_PGTABLE_H
 | |
| 
 | |
| #ifndef __ASSEMBLY__
 | |
| #ifdef CONFIG_MMU
 | |
| 
 | |
| #include <linux/mm_types.h>
 | |
| #include <linux/bug.h>
 | |
| 
 | |
| /*
 | |
|  * On almost all architectures and configurations, 0 can be used as the
 | |
|  * upper ceiling to free_pgtables(): on many architectures it has the same
 | |
|  * effect as using TASK_SIZE.  However, there is one configuration which
 | |
|  * must impose a more careful limit, to avoid freeing kernel pgtables.
 | |
|  */
 | |
| #ifndef USER_PGTABLES_CEILING
 | |
| #define USER_PGTABLES_CEILING	0UL
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
 | |
| extern int ptep_set_access_flags(struct vm_area_struct *vma,
 | |
| 				 unsigned long address, pte_t *ptep,
 | |
| 				 pte_t entry, int dirty);
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
 | |
| extern int pmdp_set_access_flags(struct vm_area_struct *vma,
 | |
| 				 unsigned long address, pmd_t *pmdp,
 | |
| 				 pmd_t entry, int dirty);
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 | |
| static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
 | |
| 					    unsigned long address,
 | |
| 					    pte_t *ptep)
 | |
| {
 | |
| 	pte_t pte = *ptep;
 | |
| 	int r = 1;
 | |
| 	if (!pte_young(pte))
 | |
| 		r = 0;
 | |
| 	else
 | |
| 		set_pte_at(vma->vm_mm, address, ptep, pte_mkold(pte));
 | |
| 	return r;
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
 | |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 | |
| static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
 | |
| 					    unsigned long address,
 | |
| 					    pmd_t *pmdp)
 | |
| {
 | |
| 	pmd_t pmd = *pmdp;
 | |
| 	int r = 1;
 | |
| 	if (!pmd_young(pmd))
 | |
| 		r = 0;
 | |
| 	else
 | |
| 		set_pmd_at(vma->vm_mm, address, pmdp, pmd_mkold(pmd));
 | |
| 	return r;
 | |
| }
 | |
| #else /* CONFIG_TRANSPARENT_HUGEPAGE */
 | |
| static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
 | |
| 					    unsigned long address,
 | |
| 					    pmd_t *pmdp)
 | |
| {
 | |
| 	BUG();
 | |
| 	return 0;
 | |
| }
 | |
| #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
 | |
| int ptep_clear_flush_young(struct vm_area_struct *vma,
 | |
| 			   unsigned long address, pte_t *ptep);
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
 | |
| int pmdp_clear_flush_young(struct vm_area_struct *vma,
 | |
| 			   unsigned long address, pmd_t *pmdp);
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
 | |
| static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
 | |
| 				       unsigned long address,
 | |
| 				       pte_t *ptep)
 | |
| {
 | |
| 	pte_t pte = *ptep;
 | |
| 	pte_clear(mm, address, ptep);
 | |
| 	return pte;
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PMDP_GET_AND_CLEAR
 | |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 | |
| static inline pmd_t pmdp_get_and_clear(struct mm_struct *mm,
 | |
| 				       unsigned long address,
 | |
| 				       pmd_t *pmdp)
 | |
| {
 | |
| 	pmd_t pmd = *pmdp;
 | |
| 	pmd_clear(pmdp);
 | |
| 	return pmd;
 | |
| }
 | |
| #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
 | |
| static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
 | |
| 					    unsigned long address, pte_t *ptep,
 | |
| 					    int full)
 | |
| {
 | |
| 	pte_t pte;
 | |
| 	pte = ptep_get_and_clear(mm, address, ptep);
 | |
| 	return pte;
 | |
| }
 | |
| #endif
 | |
| 
 | |
| /*
 | |
|  * Some architectures may be able to avoid expensive synchronization
 | |
|  * primitives when modifications are made to PTE's which are already
 | |
|  * not present, or in the process of an address space destruction.
 | |
|  */
 | |
| #ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL
 | |
| static inline void pte_clear_not_present_full(struct mm_struct *mm,
 | |
| 					      unsigned long address,
 | |
| 					      pte_t *ptep,
 | |
| 					      int full)
 | |
| {
 | |
| 	pte_clear(mm, address, ptep);
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
 | |
| extern pte_t ptep_clear_flush(struct vm_area_struct *vma,
 | |
| 			      unsigned long address,
 | |
| 			      pte_t *ptep);
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PMDP_CLEAR_FLUSH
 | |
| extern pmd_t pmdp_clear_flush(struct vm_area_struct *vma,
 | |
| 			      unsigned long address,
 | |
| 			      pmd_t *pmdp);
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
 | |
| struct mm_struct;
 | |
| static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep)
 | |
| {
 | |
| 	pte_t old_pte = *ptep;
 | |
| 	set_pte_at(mm, address, ptep, pte_wrprotect(old_pte));
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PMDP_SET_WRPROTECT
 | |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 | |
| static inline void pmdp_set_wrprotect(struct mm_struct *mm,
 | |
| 				      unsigned long address, pmd_t *pmdp)
 | |
| {
 | |
| 	pmd_t old_pmd = *pmdp;
 | |
| 	set_pmd_at(mm, address, pmdp, pmd_wrprotect(old_pmd));
 | |
| }
 | |
| #else /* CONFIG_TRANSPARENT_HUGEPAGE */
 | |
| static inline void pmdp_set_wrprotect(struct mm_struct *mm,
 | |
| 				      unsigned long address, pmd_t *pmdp)
 | |
| {
 | |
| 	BUG();
 | |
| }
 | |
| #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH
 | |
| extern void pmdp_splitting_flush(struct vm_area_struct *vma,
 | |
| 				 unsigned long address, pmd_t *pmdp);
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
 | |
| extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 | |
| 				       pgtable_t pgtable);
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
 | |
| extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PMDP_INVALIDATE
 | |
| extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 | |
| 			    pmd_t *pmdp);
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PTE_SAME
 | |
| static inline int pte_same(pte_t pte_a, pte_t pte_b)
 | |
| {
 | |
| 	return pte_val(pte_a) == pte_val(pte_b);
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PTE_UNUSED
 | |
| /*
 | |
|  * Some architectures provide facilities to virtualization guests
 | |
|  * so that they can flag allocated pages as unused. This allows the
 | |
|  * host to transparently reclaim unused pages. This function returns
 | |
|  * whether the pte's page is unused.
 | |
|  */
 | |
| static inline int pte_unused(pte_t pte)
 | |
| {
 | |
| 	return 0;
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PMD_SAME
 | |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 | |
| static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
 | |
| {
 | |
| 	return pmd_val(pmd_a) == pmd_val(pmd_b);
 | |
| }
 | |
| #else /* CONFIG_TRANSPARENT_HUGEPAGE */
 | |
| static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
 | |
| {
 | |
| 	BUG();
 | |
| 	return 0;
 | |
| }
 | |
| #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PGD_OFFSET_GATE
 | |
| #define pgd_offset_gate(mm, addr)	pgd_offset(mm, addr)
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_ARCH_MOVE_PTE
 | |
| #define move_pte(pte, prot, old_addr, new_addr)	(pte)
 | |
| #endif
 | |
| 
 | |
| #ifndef pte_accessible
 | |
| # define pte_accessible(mm, pte)	((void)(pte), 1)
 | |
| #endif
 | |
| 
 | |
| #ifndef pte_present_nonuma
 | |
| #define pte_present_nonuma(pte) pte_present(pte)
 | |
| #endif
 | |
| 
 | |
| #ifndef flush_tlb_fix_spurious_fault
 | |
| #define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address)
 | |
| #endif
 | |
| 
 | |
| #ifndef pgprot_noncached
 | |
| #define pgprot_noncached(prot)	(prot)
 | |
| #endif
 | |
| 
 | |
| #ifndef pgprot_writecombine
 | |
| #define pgprot_writecombine pgprot_noncached
 | |
| #endif
 | |
| 
 | |
| #ifndef pgprot_device
 | |
| #define pgprot_device pgprot_noncached
 | |
| #endif
 | |
| 
 | |
| #ifndef pgprot_modify
 | |
| #define pgprot_modify pgprot_modify
 | |
| static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
 | |
| {
 | |
| 	if (pgprot_val(oldprot) == pgprot_val(pgprot_noncached(oldprot)))
 | |
| 		newprot = pgprot_noncached(newprot);
 | |
| 	if (pgprot_val(oldprot) == pgprot_val(pgprot_writecombine(oldprot)))
 | |
| 		newprot = pgprot_writecombine(newprot);
 | |
| 	if (pgprot_val(oldprot) == pgprot_val(pgprot_device(oldprot)))
 | |
| 		newprot = pgprot_device(newprot);
 | |
| 	return newprot;
 | |
| }
 | |
| #endif
 | |
| 
 | |
| /*
 | |
|  * When walking page tables, get the address of the next boundary,
 | |
|  * or the end address of the range if that comes earlier.  Although no
 | |
|  * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout.
 | |
|  */
 | |
| 
 | |
| #define pgd_addr_end(addr, end)						\
 | |
| ({	unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;	\
 | |
| 	(__boundary - 1 < (end) - 1)? __boundary: (end);		\
 | |
| })
 | |
| 
 | |
| #ifndef pud_addr_end
 | |
| #define pud_addr_end(addr, end)						\
 | |
| ({	unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;	\
 | |
| 	(__boundary - 1 < (end) - 1)? __boundary: (end);		\
 | |
| })
 | |
| #endif
 | |
| 
 | |
| #ifndef pmd_addr_end
 | |
| #define pmd_addr_end(addr, end)						\
 | |
| ({	unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;	\
 | |
| 	(__boundary - 1 < (end) - 1)? __boundary: (end);		\
 | |
| })
 | |
| #endif
 | |
| 
 | |
| /*
 | |
|  * When walking page tables, we usually want to skip any p?d_none entries;
 | |
|  * and any p?d_bad entries - reporting the error before resetting to none.
 | |
|  * Do the tests inline, but report and clear the bad entry in mm/memory.c.
 | |
|  */
 | |
| void pgd_clear_bad(pgd_t *);
 | |
| void pud_clear_bad(pud_t *);
 | |
| void pmd_clear_bad(pmd_t *);
 | |
| 
 | |
| static inline int pgd_none_or_clear_bad(pgd_t *pgd)
 | |
| {
 | |
| 	if (pgd_none(*pgd))
 | |
| 		return 1;
 | |
| 	if (unlikely(pgd_bad(*pgd))) {
 | |
| 		pgd_clear_bad(pgd);
 | |
| 		return 1;
 | |
| 	}
 | |
| 	return 0;
 | |
| }
 | |
| 
 | |
| static inline int pud_none_or_clear_bad(pud_t *pud)
 | |
| {
 | |
| 	if (pud_none(*pud))
 | |
| 		return 1;
 | |
| 	if (unlikely(pud_bad(*pud))) {
 | |
| 		pud_clear_bad(pud);
 | |
| 		return 1;
 | |
| 	}
 | |
| 	return 0;
 | |
| }
 | |
| 
 | |
| static inline int pmd_none_or_clear_bad(pmd_t *pmd)
 | |
| {
 | |
| 	if (pmd_none(*pmd))
 | |
| 		return 1;
 | |
| 	if (unlikely(pmd_bad(*pmd))) {
 | |
| 		pmd_clear_bad(pmd);
 | |
| 		return 1;
 | |
| 	}
 | |
| 	return 0;
 | |
| }
 | |
| 
 | |
| static inline pte_t __ptep_modify_prot_start(struct mm_struct *mm,
 | |
| 					     unsigned long addr,
 | |
| 					     pte_t *ptep)
 | |
| {
 | |
| 	/*
 | |
| 	 * Get the current pte state, but zero it out to make it
 | |
| 	 * non-present, preventing the hardware from asynchronously
 | |
| 	 * updating it.
 | |
| 	 */
 | |
| 	return ptep_get_and_clear(mm, addr, ptep);
 | |
| }
 | |
| 
 | |
| static inline void __ptep_modify_prot_commit(struct mm_struct *mm,
 | |
| 					     unsigned long addr,
 | |
| 					     pte_t *ptep, pte_t pte)
 | |
| {
 | |
| 	/*
 | |
| 	 * The pte is non-present, so there's no hardware state to
 | |
| 	 * preserve.
 | |
| 	 */
 | |
| 	set_pte_at(mm, addr, ptep, pte);
 | |
| }
 | |
| 
 | |
| #ifndef __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
 | |
| /*
 | |
|  * Start a pte protection read-modify-write transaction, which
 | |
|  * protects against asynchronous hardware modifications to the pte.
 | |
|  * The intention is not to prevent the hardware from making pte
 | |
|  * updates, but to prevent any updates it may make from being lost.
 | |
|  *
 | |
|  * This does not protect against other software modifications of the
 | |
|  * pte; the appropriate pte lock must be held over the transation.
 | |
|  *
 | |
|  * Note that this interface is intended to be batchable, meaning that
 | |
|  * ptep_modify_prot_commit may not actually update the pte, but merely
 | |
|  * queue the update to be done at some later time.  The update must be
 | |
|  * actually committed before the pte lock is released, however.
 | |
|  */
 | |
| static inline pte_t ptep_modify_prot_start(struct mm_struct *mm,
 | |
| 					   unsigned long addr,
 | |
| 					   pte_t *ptep)
 | |
| {
 | |
| 	return __ptep_modify_prot_start(mm, addr, ptep);
 | |
| }
 | |
| 
 | |
| /*
 | |
|  * Commit an update to a pte, leaving any hardware-controlled bits in
 | |
|  * the PTE unmodified.
 | |
|  */
 | |
| static inline void ptep_modify_prot_commit(struct mm_struct *mm,
 | |
| 					   unsigned long addr,
 | |
| 					   pte_t *ptep, pte_t pte)
 | |
| {
 | |
| 	__ptep_modify_prot_commit(mm, addr, ptep, pte);
 | |
| }
 | |
| #endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
 | |
| #endif /* CONFIG_MMU */
 | |
| 
 | |
| /*
 | |
|  * A facility to provide lazy MMU batching.  This allows PTE updates and
 | |
|  * page invalidations to be delayed until a call to leave lazy MMU mode
 | |
|  * is issued.  Some architectures may benefit from doing this, and it is
 | |
|  * beneficial for both shadow and direct mode hypervisors, which may batch
 | |
|  * the PTE updates which happen during this window.  Note that using this
 | |
|  * interface requires that read hazards be removed from the code.  A read
 | |
|  * hazard could result in the direct mode hypervisor case, since the actual
 | |
|  * write to the page tables may not yet have taken place, so reads though
 | |
|  * a raw PTE pointer after it has been modified are not guaranteed to be
 | |
|  * up to date.  This mode can only be entered and left under the protection of
 | |
|  * the page table locks for all page tables which may be modified.  In the UP
 | |
|  * case, this is required so that preemption is disabled, and in the SMP case,
 | |
|  * it must synchronize the delayed page table writes properly on other CPUs.
 | |
|  */
 | |
| #ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE
 | |
| #define arch_enter_lazy_mmu_mode()	do {} while (0)
 | |
| #define arch_leave_lazy_mmu_mode()	do {} while (0)
 | |
| #define arch_flush_lazy_mmu_mode()	do {} while (0)
 | |
| #endif
 | |
| 
 | |
| /*
 | |
|  * A facility to provide batching of the reload of page tables and
 | |
|  * other process state with the actual context switch code for
 | |
|  * paravirtualized guests.  By convention, only one of the batched
 | |
|  * update (lazy) modes (CPU, MMU) should be active at any given time,
 | |
|  * entry should never be nested, and entry and exits should always be
 | |
|  * paired.  This is for sanity of maintaining and reasoning about the
 | |
|  * kernel code.  In this case, the exit (end of the context switch) is
 | |
|  * in architecture-specific code, and so doesn't need a generic
 | |
|  * definition.
 | |
|  */
 | |
| #ifndef __HAVE_ARCH_START_CONTEXT_SWITCH
 | |
| #define arch_start_context_switch(prev)	do {} while (0)
 | |
| #endif
 | |
| 
 | |
| #ifndef CONFIG_HAVE_ARCH_SOFT_DIRTY
 | |
| static inline int pte_soft_dirty(pte_t pte)
 | |
| {
 | |
| 	return 0;
 | |
| }
 | |
| 
 | |
| static inline int pmd_soft_dirty(pmd_t pmd)
 | |
| {
 | |
| 	return 0;
 | |
| }
 | |
| 
 | |
| static inline pte_t pte_mksoft_dirty(pte_t pte)
 | |
| {
 | |
| 	return pte;
 | |
| }
 | |
| 
 | |
| static inline pmd_t pmd_mksoft_dirty(pmd_t pmd)
 | |
| {
 | |
| 	return pmd;
 | |
| }
 | |
| 
 | |
| static inline pte_t pte_swp_mksoft_dirty(pte_t pte)
 | |
| {
 | |
| 	return pte;
 | |
| }
 | |
| 
 | |
| static inline int pte_swp_soft_dirty(pte_t pte)
 | |
| {
 | |
| 	return 0;
 | |
| }
 | |
| 
 | |
| static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
 | |
| {
 | |
| 	return pte;
 | |
| }
 | |
| 
 | |
| static inline pte_t pte_file_clear_soft_dirty(pte_t pte)
 | |
| {
 | |
|        return pte;
 | |
| }
 | |
| 
 | |
| static inline pte_t pte_file_mksoft_dirty(pte_t pte)
 | |
| {
 | |
|        return pte;
 | |
| }
 | |
| 
 | |
| static inline int pte_file_soft_dirty(pte_t pte)
 | |
| {
 | |
|        return 0;
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #ifndef __HAVE_PFNMAP_TRACKING
 | |
| /*
 | |
|  * Interfaces that can be used by architecture code to keep track of
 | |
|  * memory type of pfn mappings specified by the remap_pfn_range,
 | |
|  * vm_insert_pfn.
 | |
|  */
 | |
| 
 | |
| /*
 | |
|  * track_pfn_remap is called when a _new_ pfn mapping is being established
 | |
|  * by remap_pfn_range() for physical range indicated by pfn and size.
 | |
|  */
 | |
| static inline int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 | |
| 				  unsigned long pfn, unsigned long addr,
 | |
| 				  unsigned long size)
 | |
| {
 | |
| 	return 0;
 | |
| }
 | |
| 
 | |
| /*
 | |
|  * track_pfn_insert is called when a _new_ single pfn is established
 | |
|  * by vm_insert_pfn().
 | |
|  */
 | |
| static inline int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 | |
| 				   unsigned long pfn)
 | |
| {
 | |
| 	return 0;
 | |
| }
 | |
| 
 | |
| /*
 | |
|  * track_pfn_copy is called when vma that is covering the pfnmap gets
 | |
|  * copied through copy_page_range().
 | |
|  */
 | |
| static inline int track_pfn_copy(struct vm_area_struct *vma)
 | |
| {
 | |
| 	return 0;
 | |
| }
 | |
| 
 | |
| /*
 | |
|  * untrack_pfn_vma is called while unmapping a pfnmap for a region.
 | |
|  * untrack can be called for a specific region indicated by pfn and size or
 | |
|  * can be for the entire vma (in which case pfn, size are zero).
 | |
|  */
 | |
| static inline void untrack_pfn(struct vm_area_struct *vma,
 | |
| 			       unsigned long pfn, unsigned long size)
 | |
| {
 | |
| }
 | |
| #else
 | |
| extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 | |
| 			   unsigned long pfn, unsigned long addr,
 | |
| 			   unsigned long size);
 | |
| extern int track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 | |
| 			    unsigned long pfn);
 | |
| extern int track_pfn_copy(struct vm_area_struct *vma);
 | |
| extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
 | |
| 			unsigned long size);
 | |
| #endif
 | |
| 
 | |
| #ifdef __HAVE_COLOR_ZERO_PAGE
 | |
| static inline int is_zero_pfn(unsigned long pfn)
 | |
| {
 | |
| 	extern unsigned long zero_pfn;
 | |
| 	unsigned long offset_from_zero_pfn = pfn - zero_pfn;
 | |
| 	return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT);
 | |
| }
 | |
| 
 | |
| #define my_zero_pfn(addr)	page_to_pfn(ZERO_PAGE(addr))
 | |
| 
 | |
| #else
 | |
| static inline int is_zero_pfn(unsigned long pfn)
 | |
| {
 | |
| 	extern unsigned long zero_pfn;
 | |
| 	return pfn == zero_pfn;
 | |
| }
 | |
| 
 | |
| static inline unsigned long my_zero_pfn(unsigned long addr)
 | |
| {
 | |
| 	extern unsigned long zero_pfn;
 | |
| 	return zero_pfn;
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #ifdef CONFIG_MMU
 | |
| 
 | |
| #ifndef CONFIG_TRANSPARENT_HUGEPAGE
 | |
| static inline int pmd_trans_huge(pmd_t pmd)
 | |
| {
 | |
| 	return 0;
 | |
| }
 | |
| static inline int pmd_trans_splitting(pmd_t pmd)
 | |
| {
 | |
| 	return 0;
 | |
| }
 | |
| #ifndef __HAVE_ARCH_PMD_WRITE
 | |
| static inline int pmd_write(pmd_t pmd)
 | |
| {
 | |
| 	BUG();
 | |
| 	return 0;
 | |
| }
 | |
| #endif /* __HAVE_ARCH_PMD_WRITE */
 | |
| #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 | |
| 
 | |
| #ifndef pmd_read_atomic
 | |
| static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
 | |
| {
 | |
| 	/*
 | |
| 	 * Depend on compiler for an atomic pmd read. NOTE: this is
 | |
| 	 * only going to work, if the pmdval_t isn't larger than
 | |
| 	 * an unsigned long.
 | |
| 	 */
 | |
| 	return *pmdp;
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #ifndef pmd_move_must_withdraw
 | |
| static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl,
 | |
| 					 spinlock_t *old_pmd_ptl)
 | |
| {
 | |
| 	/*
 | |
| 	 * With split pmd lock we also need to move preallocated
 | |
| 	 * PTE page table if new_pmd is on different PMD page table.
 | |
| 	 */
 | |
| 	return new_pmd_ptl != old_pmd_ptl;
 | |
| }
 | |
| #endif
 | |
| 
 | |
| /*
 | |
|  * This function is meant to be used by sites walking pagetables with
 | |
|  * the mmap_sem hold in read mode to protect against MADV_DONTNEED and
 | |
|  * transhuge page faults. MADV_DONTNEED can convert a transhuge pmd
 | |
|  * into a null pmd and the transhuge page fault can convert a null pmd
 | |
|  * into an hugepmd or into a regular pmd (if the hugepage allocation
 | |
|  * fails). While holding the mmap_sem in read mode the pmd becomes
 | |
|  * stable and stops changing under us only if it's not null and not a
 | |
|  * transhuge pmd. When those races occurs and this function makes a
 | |
|  * difference vs the standard pmd_none_or_clear_bad, the result is
 | |
|  * undefined so behaving like if the pmd was none is safe (because it
 | |
|  * can return none anyway). The compiler level barrier() is critically
 | |
|  * important to compute the two checks atomically on the same pmdval.
 | |
|  *
 | |
|  * For 32bit kernels with a 64bit large pmd_t this automatically takes
 | |
|  * care of reading the pmd atomically to avoid SMP race conditions
 | |
|  * against pmd_populate() when the mmap_sem is hold for reading by the
 | |
|  * caller (a special atomic read not done by "gcc" as in the generic
 | |
|  * version above, is also needed when THP is disabled because the page
 | |
|  * fault can populate the pmd from under us).
 | |
|  */
 | |
| static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd)
 | |
| {
 | |
| 	pmd_t pmdval = pmd_read_atomic(pmd);
 | |
| 	/*
 | |
| 	 * The barrier will stabilize the pmdval in a register or on
 | |
| 	 * the stack so that it will stop changing under the code.
 | |
| 	 *
 | |
| 	 * When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE,
 | |
| 	 * pmd_read_atomic is allowed to return a not atomic pmdval
 | |
| 	 * (for example pointing to an hugepage that has never been
 | |
| 	 * mapped in the pmd). The below checks will only care about
 | |
| 	 * the low part of the pmd with 32bit PAE x86 anyway, with the
 | |
| 	 * exception of pmd_none(). So the important thing is that if
 | |
| 	 * the low part of the pmd is found null, the high part will
 | |
| 	 * be also null or the pmd_none() check below would be
 | |
| 	 * confused.
 | |
| 	 */
 | |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 | |
| 	barrier();
 | |
| #endif
 | |
| 	if (pmd_none(pmdval) || pmd_trans_huge(pmdval))
 | |
| 		return 1;
 | |
| 	if (unlikely(pmd_bad(pmdval))) {
 | |
| 		pmd_clear_bad(pmd);
 | |
| 		return 1;
 | |
| 	}
 | |
| 	return 0;
 | |
| }
 | |
| 
 | |
| /*
 | |
|  * This is a noop if Transparent Hugepage Support is not built into
 | |
|  * the kernel. Otherwise it is equivalent to
 | |
|  * pmd_none_or_trans_huge_or_clear_bad(), and shall only be called in
 | |
|  * places that already verified the pmd is not none and they want to
 | |
|  * walk ptes while holding the mmap sem in read mode (write mode don't
 | |
|  * need this). If THP is not enabled, the pmd can't go away under the
 | |
|  * code even if MADV_DONTNEED runs, but if THP is enabled we need to
 | |
|  * run a pmd_trans_unstable before walking the ptes after
 | |
|  * split_huge_page_pmd returns (because it may have run when the pmd
 | |
|  * become null, but then a page fault can map in a THP and not a
 | |
|  * regular page).
 | |
|  */
 | |
| static inline int pmd_trans_unstable(pmd_t *pmd)
 | |
| {
 | |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 | |
| 	return pmd_none_or_trans_huge_or_clear_bad(pmd);
 | |
| #else
 | |
| 	return 0;
 | |
| #endif
 | |
| }
 | |
| 
 | |
| #ifdef CONFIG_NUMA_BALANCING
 | |
| /*
 | |
|  * _PAGE_NUMA distinguishes between an unmapped page table entry, an entry that
 | |
|  * is protected for PROT_NONE and a NUMA hinting fault entry. If the
 | |
|  * architecture defines __PAGE_PROTNONE then it should take that into account
 | |
|  * but those that do not can rely on the fact that the NUMA hinting scanner
 | |
|  * skips inaccessible VMAs.
 | |
|  *
 | |
|  * pte/pmd_present() returns true if pte/pmd_numa returns true. Page
 | |
|  * fault triggers on those regions if pte/pmd_numa returns true
 | |
|  * (because _PAGE_PRESENT is not set).
 | |
|  */
 | |
| #ifndef pte_numa
 | |
| static inline int pte_numa(pte_t pte)
 | |
| {
 | |
| 	return ptenuma_flags(pte) == _PAGE_NUMA;
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #ifndef pmd_numa
 | |
| static inline int pmd_numa(pmd_t pmd)
 | |
| {
 | |
| 	return pmdnuma_flags(pmd) == _PAGE_NUMA;
 | |
| }
 | |
| #endif
 | |
| 
 | |
| /*
 | |
|  * pte/pmd_mknuma sets the _PAGE_ACCESSED bitflag automatically
 | |
|  * because they're called by the NUMA hinting minor page fault. If we
 | |
|  * wouldn't set the _PAGE_ACCESSED bitflag here, the TLB miss handler
 | |
|  * would be forced to set it later while filling the TLB after we
 | |
|  * return to userland. That would trigger a second write to memory
 | |
|  * that we optimize away by setting _PAGE_ACCESSED here.
 | |
|  */
 | |
| #ifndef pte_mknonnuma
 | |
| static inline pte_t pte_mknonnuma(pte_t pte)
 | |
| {
 | |
| 	pteval_t val = pte_val(pte);
 | |
| 
 | |
| 	val &= ~_PAGE_NUMA;
 | |
| 	val |= (_PAGE_PRESENT|_PAGE_ACCESSED);
 | |
| 	return __pte(val);
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #ifndef pmd_mknonnuma
 | |
| static inline pmd_t pmd_mknonnuma(pmd_t pmd)
 | |
| {
 | |
| 	pmdval_t val = pmd_val(pmd);
 | |
| 
 | |
| 	val &= ~_PAGE_NUMA;
 | |
| 	val |= (_PAGE_PRESENT|_PAGE_ACCESSED);
 | |
| 
 | |
| 	return __pmd(val);
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #ifndef pte_mknuma
 | |
| static inline pte_t pte_mknuma(pte_t pte)
 | |
| {
 | |
| 	pteval_t val = pte_val(pte);
 | |
| 
 | |
| 	VM_BUG_ON(!(val & _PAGE_PRESENT));
 | |
| 
 | |
| 	val &= ~_PAGE_PRESENT;
 | |
| 	val |= _PAGE_NUMA;
 | |
| 
 | |
| 	return __pte(val);
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #ifndef ptep_set_numa
 | |
| static inline void ptep_set_numa(struct mm_struct *mm, unsigned long addr,
 | |
| 				 pte_t *ptep)
 | |
| {
 | |
| 	pte_t ptent = *ptep;
 | |
| 
 | |
| 	ptent = pte_mknuma(ptent);
 | |
| 	set_pte_at(mm, addr, ptep, ptent);
 | |
| 	return;
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #ifndef pmd_mknuma
 | |
| static inline pmd_t pmd_mknuma(pmd_t pmd)
 | |
| {
 | |
| 	pmdval_t val = pmd_val(pmd);
 | |
| 
 | |
| 	val &= ~_PAGE_PRESENT;
 | |
| 	val |= _PAGE_NUMA;
 | |
| 
 | |
| 	return __pmd(val);
 | |
| }
 | |
| #endif
 | |
| 
 | |
| #ifndef pmdp_set_numa
 | |
| static inline void pmdp_set_numa(struct mm_struct *mm, unsigned long addr,
 | |
| 				 pmd_t *pmdp)
 | |
| {
 | |
| 	pmd_t pmd = *pmdp;
 | |
| 
 | |
| 	pmd = pmd_mknuma(pmd);
 | |
| 	set_pmd_at(mm, addr, pmdp, pmd);
 | |
| 	return;
 | |
| }
 | |
| #endif
 | |
| #else
 | |
| static inline int pmd_numa(pmd_t pmd)
 | |
| {
 | |
| 	return 0;
 | |
| }
 | |
| 
 | |
| static inline int pte_numa(pte_t pte)
 | |
| {
 | |
| 	return 0;
 | |
| }
 | |
| 
 | |
| static inline pte_t pte_mknonnuma(pte_t pte)
 | |
| {
 | |
| 	return pte;
 | |
| }
 | |
| 
 | |
| static inline pmd_t pmd_mknonnuma(pmd_t pmd)
 | |
| {
 | |
| 	return pmd;
 | |
| }
 | |
| 
 | |
| static inline pte_t pte_mknuma(pte_t pte)
 | |
| {
 | |
| 	return pte;
 | |
| }
 | |
| 
 | |
| static inline void ptep_set_numa(struct mm_struct *mm, unsigned long addr,
 | |
| 				 pte_t *ptep)
 | |
| {
 | |
| 	return;
 | |
| }
 | |
| 
 | |
| 
 | |
| static inline pmd_t pmd_mknuma(pmd_t pmd)
 | |
| {
 | |
| 	return pmd;
 | |
| }
 | |
| 
 | |
| static inline void pmdp_set_numa(struct mm_struct *mm, unsigned long addr,
 | |
| 				 pmd_t *pmdp)
 | |
| {
 | |
| 	return ;
 | |
| }
 | |
| #endif /* CONFIG_NUMA_BALANCING */
 | |
| 
 | |
| #endif /* CONFIG_MMU */
 | |
| 
 | |
| #endif /* !__ASSEMBLY__ */
 | |
| 
 | |
| #ifndef io_remap_pfn_range
 | |
| #define io_remap_pfn_range remap_pfn_range
 | |
| #endif
 | |
| 
 | |
| #endif /* _ASM_GENERIC_PGTABLE_H */
 |