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tile: fix some issues in hugepage support

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First, in huge_pte_offset(), we were erroneously checking
pgd_present(), which is always true, rather than pud_present(),
which is the thing that tells us if there is a top-level (L0) PTE.
Fixing this means we properly look up huge page entries only when
the Present bit is actually set in the PTE.

Second, use the standard pte_alloc_map() instead of the hand-rolled
pte_alloc_hugetlb() routine that basically was written to avoid
worrying about CONFIG_HIGHPTE.  However, we no longer plan to support
HIGHPTE, so a separate routine was just unnecessary code duplication.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
This commit is contained in:
Chris Metcalf 2013-08-07 11:00:45 -04:00
parent 6b940606d9
commit a0bd12d718
1 changed files with 3 additions and 35 deletions
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38
arch/tile/mm/hugetlbpage.c
View file

@ -49,38 +49,6 @@ int huge_shift[HUGE_SHIFT_ENTRIES] = {
#endif #endif
}; };
/*
* This routine is a hybrid of pte_alloc_map() and pte_alloc_kernel().
* It assumes that L2 PTEs are never in HIGHMEM (we don't support that).
* It locks the user pagetable, and bumps up the mm->nr_ptes field,
* but otherwise allocate the page table using the kernel versions.
*/
static pte_t *pte_alloc_hugetlb(struct mm_struct *mm, pmd_t *pmd,
unsigned long address)
{
pte_t *new;
if (pmd_none(*pmd)) {
new = pte_alloc_one_kernel(mm, address);
if (!new)
return NULL;
smp_wmb(); /* See comment in __pte_alloc */
spin_lock(&mm->page_table_lock);
if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
mm->nr_ptes++;
pmd_populate_kernel(mm, pmd, new);
new = NULL;
} else
VM_BUG_ON(pmd_trans_splitting(*pmd));
spin_unlock(&mm->page_table_lock);
if (new)
pte_free_kernel(mm, new);
}
return pte_offset_kernel(pmd, address);
}
#endif #endif
pte_t *huge_pte_alloc(struct mm_struct *mm, pte_t *huge_pte_alloc(struct mm_struct *mm,
@ -109,7 +77,7 @@ pte_t *huge_pte_alloc(struct mm_struct *mm,
else { else {
if (sz != PAGE_SIZE << huge_shift[HUGE_SHIFT_PAGE]) if (sz != PAGE_SIZE << huge_shift[HUGE_SHIFT_PAGE])
panic("Unexpected page size %#lx\n", sz); panic("Unexpected page size %#lx\n", sz);
return pte_alloc_hugetlb(mm, pmd, addr); return pte_alloc_map(mm, NULL, pmd, addr);
} }
} }
#else #else
@ -144,14 +112,14 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
/* Get the top-level page table entry. */ /* Get the top-level page table entry. */
pgd = (pgd_t *)get_pte((pte_t *)mm->pgd, pgd_index(addr), 0); pgd = (pgd_t *)get_pte((pte_t *)mm->pgd, pgd_index(addr), 0);
if (!pgd_present(*pgd))
return NULL;
/* We don't have four levels. */ /* We don't have four levels. */
pud = pud_offset(pgd, addr); pud = pud_offset(pgd, addr);
#ifndef __PAGETABLE_PUD_FOLDED #ifndef __PAGETABLE_PUD_FOLDED
# error support fourth page table level # error support fourth page table level
#endif #endif
if (!pud_present(*pud))
return NULL;
/* Check for an L0 huge PTE, if we have three levels. */ /* Check for an L0 huge PTE, if we have three levels. */
#ifndef __PAGETABLE_PMD_FOLDED #ifndef __PAGETABLE_PMD_FOLDED