tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
tile: fix some issues in hugepage support
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>
+3
-35
+3
-35
arch/tile/mm/hugetlbpage.c
+3
-35
arch/tile/mm/hugetlbpage.c
···
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#endif
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};
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-
/*
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* This routine is a hybrid of pte_alloc_map() and pte_alloc_kernel().
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* It assumes that L2 PTEs are never in HIGHMEM (we don't support that).
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* It locks the user pagetable, and bumps up the mm->nr_ptes field,
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* but otherwise allocate the page table using the kernel versions.
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*/
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static pte_t *pte_alloc_hugetlb(struct mm_struct *mm, pmd_t *pmd,
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unsigned long address)
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{
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pte_t *new;
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if (pmd_none(*pmd)) {
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new = pte_alloc_one_kernel(mm, address);
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if (!new)
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return NULL;
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smp_wmb(); /* See comment in __pte_alloc */
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spin_lock(&mm->page_table_lock);
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if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
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mm->nr_ptes++;
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pmd_populate_kernel(mm, pmd, new);
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new = NULL;
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} else
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VM_BUG_ON(pmd_trans_splitting(*pmd));
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spin_unlock(&mm->page_table_lock);
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if (new)
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pte_free_kernel(mm, new);
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}
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return pte_offset_kernel(pmd, address);
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}
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#endif
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pte_t *huge_pte_alloc(struct mm_struct *mm,
···
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else {
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if (sz != PAGE_SIZE << huge_shift[HUGE_SHIFT_PAGE])
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panic("Unexpected page size %#lx\n", sz);
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return pte_alloc_hugetlb(mm, pmd, addr);
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return pte_alloc_map(mm, NULL, pmd, addr);
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}
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}
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#else
···
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/* Get the top-level page table entry. */
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pgd = (pgd_t *)get_pte((pte_t *)mm->pgd, pgd_index(addr), 0);
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if (!pgd_present(*pgd))
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return NULL;
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/* We don't have four levels. */
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pud = pud_offset(pgd, addr);
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#ifndef __PAGETABLE_PUD_FOLDED
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# error support fourth page table level
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#endif
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+
if (!pud_present(*pud))
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return NULL;
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/* Check for an L0 huge PTE, if we have three levels. */
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#ifndef __PAGETABLE_PMD_FOLDED