kernel-ark/include/asm-generic/pgtable.h
Nick Piggin 8b1f312461 [PATCH] mm: move_pte to remap ZERO_PAGE
Move the ZERO_PAGE remapping complexity to the move_pte macro in
asm-generic, have it conditionally depend on
__HAVE_ARCH_MULTIPLE_ZERO_PAGE, which gets defined for MIPS.

For architectures without __HAVE_ARCH_MULTIPLE_ZERO_PAGE, move_pte becomes
a noop.

From: Hugh Dickins <hugh@veritas.com>

Fix nasty little bug we've missed in Nick's mremap move ZERO_PAGE patch.
The "pte" at that point may be a swap entry or a pte_file entry: we must
check pte_present before perhaps corrupting such an entry.

Patch below against 2.6.14-rc2-mm1, but the same bug is in 2.6.14-rc2's
mm/mremap.c, and more dangerous there since it's affecting all arches: I
think the safest course is to send Nick's patch and Yoichi's build fix and
this fix (build tested) on to Linus - so only MIPS can be affected.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-28 07:46:40 -07:00

244 lines
6.3 KiB
C

#ifndef _ASM_GENERIC_PGTABLE_H
#define _ASM_GENERIC_PGTABLE_H
#ifndef __HAVE_ARCH_PTEP_ESTABLISH
/*
* Establish a new mapping:
* - flush the old one
* - update the page tables
* - inform the TLB about the new one
*
* We hold the mm semaphore for reading and vma->vm_mm->page_table_lock.
*
* Note: the old pte is known to not be writable, so we don't need to
* worry about dirty bits etc getting lost.
*/
#ifndef __HAVE_ARCH_SET_PTE_ATOMIC
#define ptep_establish(__vma, __address, __ptep, __entry) \
do { \
set_pte_at((__vma)->vm_mm, (__address), __ptep, __entry); \
flush_tlb_page(__vma, __address); \
} while (0)
#else /* __HAVE_ARCH_SET_PTE_ATOMIC */
#define ptep_establish(__vma, __address, __ptep, __entry) \
do { \
set_pte_atomic(__ptep, __entry); \
flush_tlb_page(__vma, __address); \
} while (0)
#endif /* __HAVE_ARCH_SET_PTE_ATOMIC */
#endif
#ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
/*
* Largely same as above, but only sets the access flags (dirty,
* accessed, and writable). Furthermore, we know it always gets set
* to a "more permissive" setting, which allows most architectures
* to optimize this.
*/
#define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
do { \
set_pte_at((__vma)->vm_mm, (__address), __ptep, __entry); \
flush_tlb_page(__vma, __address); \
} while (0)
#endif
#ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
#define ptep_test_and_clear_young(__vma, __address, __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)); \
r; \
})
#endif
#ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
#define ptep_clear_flush_young(__vma, __address, __ptep) \
({ \
int __young; \
__young = ptep_test_and_clear_young(__vma, __address, __ptep); \
if (__young) \
flush_tlb_page(__vma, __address); \
__young; \
})
#endif
#ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
#define ptep_test_and_clear_dirty(__vma, __address, __ptep) \
({ \
pte_t __pte = *__ptep; \
int r = 1; \
if (!pte_dirty(__pte)) \
r = 0; \
else \
set_pte_at((__vma)->vm_mm, (__address), (__ptep), \
pte_mkclean(__pte)); \
r; \
})
#endif
#ifndef __HAVE_ARCH_PTEP_CLEAR_DIRTY_FLUSH
#define ptep_clear_flush_dirty(__vma, __address, __ptep) \
({ \
int __dirty; \
__dirty = ptep_test_and_clear_dirty(__vma, __address, __ptep); \
if (__dirty) \
flush_tlb_page(__vma, __address); \
__dirty; \
})
#endif
#ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
#define ptep_get_and_clear(__mm, __address, __ptep) \
({ \
pte_t __pte = *(__ptep); \
pte_clear((__mm), (__address), (__ptep)); \
__pte; \
})
#endif
#ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
#define ptep_get_and_clear_full(__mm, __address, __ptep, __full) \
({ \
pte_t __pte; \
__pte = ptep_get_and_clear((__mm), (__address), (__ptep)); \
__pte; \
})
#endif
#ifndef __HAVE_ARCH_PTE_CLEAR_FULL
#define pte_clear_full(__mm, __address, __ptep, __full) \
do { \
pte_clear((__mm), (__address), (__ptep)); \
} while (0)
#endif
#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
#define ptep_clear_flush(__vma, __address, __ptep) \
({ \
pte_t __pte; \
__pte = ptep_get_and_clear((__vma)->vm_mm, __address, __ptep); \
flush_tlb_page(__vma, __address); \
__pte; \
})
#endif
#ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
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_PTE_SAME
#define pte_same(A,B) (pte_val(A) == pte_val(B))
#endif
#ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY
#define page_test_and_clear_dirty(page) (0)
#define pte_maybe_dirty(pte) pte_dirty(pte)
#else
#define pte_maybe_dirty(pte) (1)
#endif
#ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG
#define page_test_and_clear_young(page) (0)
#endif
#ifndef __HAVE_ARCH_PGD_OFFSET_GATE
#define pgd_offset_gate(mm, addr) pgd_offset(mm, addr)
#endif
#ifndef __HAVE_ARCH_LAZY_MMU_PROT_UPDATE
#define lazy_mmu_prot_update(pte) do { } while (0)
#endif
#ifndef __HAVE_ARCH_MULTIPLE_ZERO_PAGE
#define move_pte(pte, prot, old_addr, new_addr) (pte)
#else
#define move_pte(pte, prot, old_addr, new_addr) \
({ \
pte_t newpte = (pte); \
if (pte_present(pte) && pfn_valid(pte_pfn(pte)) && \
pte_page(pte) == ZERO_PAGE(old_addr)) \
newpte = mk_pte(ZERO_PAGE(new_addr), (prot)); \
newpte; \
})
#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
#ifndef __ASSEMBLY__
/*
* 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;
}
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_GENERIC_PGTABLE_H */