bf72aeba2f
Some POWER5+ machines can do 64k hardware pages for normal memory but not for cache-inhibited pages. This patch lets us use 64k hardware pages for most user processes on such machines (assuming the kernel has been configured with CONFIG_PPC_64K_PAGES=y). User processes start out using 64k pages and get switched to 4k pages if they use any non-cacheable mappings. With this, we use 64k pages for the vmalloc region and 4k pages for the imalloc region. If anything creates a non-cacheable mapping in the vmalloc region, the vmalloc region will get switched to 4k pages. I don't know of any driver other than the DRM that would do this, though, and these machines don't have AGP. When a region gets switched from 64k pages to 4k pages, we do not have to clear out all the 64k HPTEs from the hash table immediately. We use the _PAGE_COMBO bit in the Linux PTE to indicate whether the page was hashed in as a 64k page or a set of 4k pages. If hash_page is trying to insert a 4k page for a Linux PTE and it sees that it has already been inserted as a 64k page, it first invalidates the 64k HPTE before inserting the 4k HPTE. The hash invalidation routines also use the _PAGE_COMBO bit, to determine whether to look for a 64k HPTE or a set of 4k HPTEs to remove. With those two changes, we can tolerate a mix of 4k and 64k HPTEs in the hash table, and they will all get removed when the address space is torn down. Signed-off-by: Paul Mackerras <paulus@samba.org>
98 lines
3.3 KiB
C
98 lines
3.3 KiB
C
/*
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* Entries per page directory level. The PTE level must use a 64b record
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* for each page table entry. The PMD and PGD level use a 32b record for
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* each entry by assuming that each entry is page aligned.
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*/
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#define PTE_INDEX_SIZE 9
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#define PMD_INDEX_SIZE 7
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#define PUD_INDEX_SIZE 7
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#define PGD_INDEX_SIZE 9
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#define PTE_TABLE_SIZE (sizeof(pte_t) << PTE_INDEX_SIZE)
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#define PMD_TABLE_SIZE (sizeof(pmd_t) << PMD_INDEX_SIZE)
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#define PUD_TABLE_SIZE (sizeof(pud_t) << PUD_INDEX_SIZE)
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#define PGD_TABLE_SIZE (sizeof(pgd_t) << PGD_INDEX_SIZE)
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#define PTRS_PER_PTE (1 << PTE_INDEX_SIZE)
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#define PTRS_PER_PMD (1 << PMD_INDEX_SIZE)
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#define PTRS_PER_PUD (1 << PMD_INDEX_SIZE)
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#define PTRS_PER_PGD (1 << PGD_INDEX_SIZE)
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/* PMD_SHIFT determines what a second-level page table entry can map */
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#define PMD_SHIFT (PAGE_SHIFT + PTE_INDEX_SIZE)
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#define PMD_SIZE (1UL << PMD_SHIFT)
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#define PMD_MASK (~(PMD_SIZE-1))
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/* With 4k base page size, hugepage PTEs go at the PMD level */
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#define MIN_HUGEPTE_SHIFT PMD_SHIFT
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/* PUD_SHIFT determines what a third-level page table entry can map */
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#define PUD_SHIFT (PMD_SHIFT + PMD_INDEX_SIZE)
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#define PUD_SIZE (1UL << PUD_SHIFT)
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#define PUD_MASK (~(PUD_SIZE-1))
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/* PGDIR_SHIFT determines what a fourth-level page table entry can map */
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#define PGDIR_SHIFT (PUD_SHIFT + PUD_INDEX_SIZE)
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#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
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#define PGDIR_MASK (~(PGDIR_SIZE-1))
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/* PTE bits */
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#define _PAGE_SECONDARY 0x8000 /* software: HPTE is in secondary group */
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#define _PAGE_GROUP_IX 0x7000 /* software: HPTE index within group */
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#define _PAGE_F_SECOND _PAGE_SECONDARY
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#define _PAGE_F_GIX _PAGE_GROUP_IX
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/* PTE flags to conserve for HPTE identification */
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#define _PAGE_HPTEFLAGS (_PAGE_BUSY | _PAGE_HASHPTE | \
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_PAGE_SECONDARY | _PAGE_GROUP_IX)
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/* PAGE_MASK gives the right answer below, but only by accident */
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/* It should be preserving the high 48 bits and then specifically */
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/* preserving _PAGE_SECONDARY | _PAGE_GROUP_IX */
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#define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY | \
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_PAGE_HPTEFLAGS)
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/* Bits to mask out from a PMD to get to the PTE page */
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#define PMD_MASKED_BITS 0
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/* Bits to mask out from a PUD to get to the PMD page */
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#define PUD_MASKED_BITS 0
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/* Bits to mask out from a PGD to get to the PUD page */
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#define PGD_MASKED_BITS 0
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/* shift to put page number into pte */
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#define PTE_RPN_SHIFT (17)
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#ifdef STRICT_MM_TYPECHECKS
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#define __real_pte(e,p) ((real_pte_t){(e)})
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#define __rpte_to_pte(r) ((r).pte)
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#else
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#define __real_pte(e,p) (e)
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#define __rpte_to_pte(r) (__pte(r))
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#endif
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#define __rpte_to_hidx(r,index) (pte_val(__rpte_to_pte(r)) >> 12)
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#define pte_iterate_hashed_subpages(rpte, psize, va, index, shift) \
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do { \
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index = 0; \
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shift = mmu_psize_defs[psize].shift; \
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#define pte_iterate_hashed_end() } while(0)
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#define pte_pagesize_index(pte) MMU_PAGE_4K
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/*
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* 4-level page tables related bits
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*/
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#define pgd_none(pgd) (!pgd_val(pgd))
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#define pgd_bad(pgd) (pgd_val(pgd) == 0)
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#define pgd_present(pgd) (pgd_val(pgd) != 0)
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#define pgd_clear(pgdp) (pgd_val(*(pgdp)) = 0)
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#define pgd_page(pgd) (pgd_val(pgd) & ~PGD_MASKED_BITS)
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#define pud_offset(pgdp, addr) \
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(((pud_t *) pgd_page(*(pgdp))) + \
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(((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1)))
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#define pud_ERROR(e) \
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printk("%s:%d: bad pud %08lx.\n", __FILE__, __LINE__, pud_val(e))
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