forked from mirrors/linux
		
	Add support for transparent hugepages to x86 32bit. Share the same VM_ bitflag for VM_MAPPED_COPY. mm/nommu.c will never support transparent hugepages. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
		
			
				
	
	
		
			111 lines
		
	
	
	
		
			3.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			111 lines
		
	
	
	
		
			3.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
#ifndef _ASM_X86_PGTABLE_2LEVEL_H
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#define _ASM_X86_PGTABLE_2LEVEL_H
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#define pte_ERROR(e) \
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	printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, (e).pte_low)
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#define pgd_ERROR(e) \
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	printk("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
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/*
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 * Certain architectures need to do special things when PTEs
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 * within a page table are directly modified.  Thus, the following
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 * hook is made available.
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 */
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static inline void native_set_pte(pte_t *ptep , pte_t pte)
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{
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	*ptep = pte;
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}
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static inline void native_set_pmd(pmd_t *pmdp, pmd_t pmd)
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{
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	*pmdp = pmd;
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}
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static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte)
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{
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	native_set_pte(ptep, pte);
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}
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static inline void native_pmd_clear(pmd_t *pmdp)
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{
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	native_set_pmd(pmdp, __pmd(0));
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}
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static inline void native_pte_clear(struct mm_struct *mm,
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				    unsigned long addr, pte_t *xp)
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{
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	*xp = native_make_pte(0);
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}
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#ifdef CONFIG_SMP
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static inline pte_t native_ptep_get_and_clear(pte_t *xp)
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{
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	return __pte(xchg(&xp->pte_low, 0));
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}
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#else
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#define native_ptep_get_and_clear(xp) native_local_ptep_get_and_clear(xp)
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#endif
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#ifdef CONFIG_SMP
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static inline pmd_t native_pmdp_get_and_clear(pmd_t *xp)
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{
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	return __pmd(xchg((pmdval_t *)xp, 0));
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}
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#else
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#define native_pmdp_get_and_clear(xp) native_local_pmdp_get_and_clear(xp)
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#endif
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/*
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 * Bits _PAGE_BIT_PRESENT, _PAGE_BIT_FILE and _PAGE_BIT_PROTNONE are taken,
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 * split up the 29 bits of offset into this range:
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 */
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#define PTE_FILE_MAX_BITS	29
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#define PTE_FILE_SHIFT1		(_PAGE_BIT_PRESENT + 1)
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#if _PAGE_BIT_FILE < _PAGE_BIT_PROTNONE
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#define PTE_FILE_SHIFT2		(_PAGE_BIT_FILE + 1)
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#define PTE_FILE_SHIFT3		(_PAGE_BIT_PROTNONE + 1)
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#else
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#define PTE_FILE_SHIFT2		(_PAGE_BIT_PROTNONE + 1)
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#define PTE_FILE_SHIFT3		(_PAGE_BIT_FILE + 1)
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#endif
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#define PTE_FILE_BITS1		(PTE_FILE_SHIFT2 - PTE_FILE_SHIFT1 - 1)
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#define PTE_FILE_BITS2		(PTE_FILE_SHIFT3 - PTE_FILE_SHIFT2 - 1)
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#define pte_to_pgoff(pte)						\
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	((((pte).pte_low >> PTE_FILE_SHIFT1)				\
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	  & ((1U << PTE_FILE_BITS1) - 1))				\
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	 + ((((pte).pte_low >> PTE_FILE_SHIFT2)				\
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	     & ((1U << PTE_FILE_BITS2) - 1)) << PTE_FILE_BITS1)		\
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	 + (((pte).pte_low >> PTE_FILE_SHIFT3)				\
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	    << (PTE_FILE_BITS1 + PTE_FILE_BITS2)))
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#define pgoff_to_pte(off)						\
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	((pte_t) { .pte_low =						\
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	 (((off) & ((1U << PTE_FILE_BITS1) - 1)) << PTE_FILE_SHIFT1)	\
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	 + ((((off) >> PTE_FILE_BITS1) & ((1U << PTE_FILE_BITS2) - 1))	\
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	    << PTE_FILE_SHIFT2)						\
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	 + (((off) >> (PTE_FILE_BITS1 + PTE_FILE_BITS2))		\
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	    << PTE_FILE_SHIFT3)						\
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	 + _PAGE_FILE })
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/* Encode and de-code a swap entry */
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#if _PAGE_BIT_FILE < _PAGE_BIT_PROTNONE
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#define SWP_TYPE_BITS (_PAGE_BIT_FILE - _PAGE_BIT_PRESENT - 1)
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#define SWP_OFFSET_SHIFT (_PAGE_BIT_PROTNONE + 1)
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#else
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#define SWP_TYPE_BITS (_PAGE_BIT_PROTNONE - _PAGE_BIT_PRESENT - 1)
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#define SWP_OFFSET_SHIFT (_PAGE_BIT_FILE + 1)
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#endif
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#define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > SWP_TYPE_BITS)
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#define __swp_type(x)			(((x).val >> (_PAGE_BIT_PRESENT + 1)) \
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					 & ((1U << SWP_TYPE_BITS) - 1))
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#define __swp_offset(x)			((x).val >> SWP_OFFSET_SHIFT)
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#define __swp_entry(type, offset)	((swp_entry_t) { \
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					 ((type) << (_PAGE_BIT_PRESENT + 1)) \
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					 | ((offset) << SWP_OFFSET_SHIFT) })
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#define __pte_to_swp_entry(pte)		((swp_entry_t) { (pte).pte_low })
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#define __swp_entry_to_pte(x)		((pte_t) { .pte = (x).val })
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#endif /* _ASM_X86_PGTABLE_2LEVEL_H */
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