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Commit a0bd12d7 authored by Chris Metcalf's avatar Chris Metcalf
Browse files

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: default avatarChris Metcalf <cmetcalf@tilera.com>
parent 6b940606

arch/tile/mm/hugetlbpage.c

+3 −35
Original line number Diff line number Diff line
@@ -49,38 +49,6 @@ int huge_shift[HUGE_SHIFT_ENTRIES] = { 
#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



pte_t *huge_pte_alloc(struct mm_struct *mm,
@@ -109,7 +77,7 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, 
		else {

			if (sz != PAGE_SIZE << huge_shift[HUGE_SHIFT_PAGE])

				panic("Unexpected page size %#lx\n", sz);

			return pte_alloc_hugetlb(mm, pmd, addr);

			return pte_alloc_map(mm, NULL, pmd, addr);

		}

	}

#else
@@ -144,14 +112,14 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) 


	/* Get the top-level page table entry. */

	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. */

	pud = pud_offset(pgd, addr);

#ifndef __PAGETABLE_PUD_FOLDED

# error support fourth page table level

#endif

	if (!pud_present(*pud))

		return NULL;



	/* Check for an L0 huge PTE, if we have three levels. */

#ifndef __PAGETABLE_PMD_FOLDED