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#ifndef _GENERIC_RMAP_H
#define _GENERIC_RMAP_H
/*
* linux/include/asm-generic/rmap.h
*
* Architecture dependent parts of the reverse mapping code,
* this version should work for most architectures with a
* 'normal' page table layout.
*
* We use the struct page of the page table page to find out
* the process and full address of a page table entry:
* - page->mapping points to the process' mm_struct
* - page->index has the high bits of the address
* - the lower bits of the address are calculated from the
* offset of the page table entry within the page table page
*
* For CONFIG_HIGHPTE, we need to represent the address of a pte in a
* scalar pte_addr_t. The pfn of the pte's page is shifted left by PAGE_SIZE
* bits and is then ORed with the byte offset of the pte within its page.
*
* For CONFIG_HIGHMEM4G, the pte_addr_t is 32 bits. 20 for the pfn, 12 for
* the offset.
*
* For CONFIG_HIGHMEM64G, the pte_addr_t is 64 bits. 52 for the pfn, 12 for
* the offset.
*/
#include <linux/mm.h>
static inline void pgtable_add_rmap(struct page * page, struct mm_struct * mm, unsigned long address)
{
#ifdef BROKEN_PPC_PTE_ALLOC_ONE
/* OK, so PPC calls pte_alloc() before mem_map[] is setup ... ;( */
extern int mem_init_done;
if (!mem_init_done)
return;
#endif
page->mapping = (void *)mm;
page->index = address & ~((PTRS_PER_PTE * PAGE_SIZE) - 1);
inc_page_state(nr_page_table_pages);
}
static inline void pgtable_remove_rmap(struct page * page)
{
page->mapping = NULL;
page->index = 0;
dec_page_state(nr_page_table_pages);
}
static inline struct mm_struct * ptep_to_mm(pte_t * ptep)
{
struct page * page = kmap_atomic_to_page(ptep);
return (struct mm_struct *) page->mapping;
}
static inline unsigned long ptep_to_address(pte_t * ptep)
{
struct page * page = kmap_atomic_to_page(ptep);
unsigned long low_bits;
low_bits = ((unsigned long)ptep & ~PAGE_MASK) * PTRS_PER_PTE;
return page->index + low_bits;
}
#ifdef CONFIG_HIGHPTE
static inline pte_addr_t ptep_to_paddr(pte_t *ptep)
{
pte_addr_t paddr;
paddr = ((pte_addr_t)page_to_pfn(kmap_atomic_to_page(ptep))) << PAGE_SHIFT;
return paddr + (pte_addr_t)((unsigned long)ptep & ~PAGE_MASK);
}
#else
static inline pte_addr_t ptep_to_paddr(pte_t *ptep)
{
return (pte_addr_t)ptep;
}
#endif
#ifndef CONFIG_HIGHPTE
static inline pte_t *rmap_ptep_map(pte_addr_t pte_paddr)
{
return (pte_t *)pte_paddr;
}
static inline void rmap_ptep_unmap(pte_t *pte)
{
return;
}
#endif
#endif /* _GENERIC_RMAP_H */
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