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
3.6 KiB
C
98 lines
3.6 KiB
C
#ifndef _ASM_POWERPC_PGTABLE_64K_H
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#define _ASM_POWERPC_PGTABLE_64K_H
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#ifdef __KERNEL__
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#include <asm-generic/pgtable-nopud.h>
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#define PTE_INDEX_SIZE 12
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#define PMD_INDEX_SIZE 12
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#define PUD_INDEX_SIZE 0
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#define PGD_INDEX_SIZE 4
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#define PTE_TABLE_SIZE (sizeof(real_pte_t) << PTE_INDEX_SIZE)
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#define PMD_TABLE_SIZE (sizeof(pmd_t) << PMD_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_PGD (1 << PGD_INDEX_SIZE)
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/* With 4k base page size, hugepage PTEs go at the PMD level */
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#define MIN_HUGEPTE_SHIFT PAGE_SHIFT
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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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/* PGDIR_SHIFT determines what a third-level page table entry can map */
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#define PGDIR_SHIFT (PMD_SHIFT + PMD_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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/* Additional PTE bits (don't change without checking asm in hash_low.S) */
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#define _PAGE_HPTE_SUB 0x0ffff000 /* combo only: sub pages HPTE bits */
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#define _PAGE_HPTE_SUB0 0x08000000 /* combo only: first sub page */
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#define _PAGE_COMBO 0x10000000 /* this is a combo 4k page */
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#define _PAGE_F_SECOND 0x00008000 /* full page: hidx bits */
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#define _PAGE_F_GIX 0x00007000 /* full page: hidx bits */
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/* PTE flags to conserve for HPTE identification */
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#define _PAGE_HPTEFLAGS (_PAGE_BUSY | _PAGE_HASHPTE | _PAGE_HPTE_SUB |\
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_PAGE_COMBO)
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/* Shift to put page number into pte.
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*
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* That gives us a max RPN of 32 bits, which means a max of 48 bits
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* of addressable physical space.
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* We could get 3 more bits here by setting PTE_RPN_SHIFT to 29 but
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* 32 makes PTEs more readable for debugging for now :)
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*/
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#define PTE_RPN_SHIFT (32)
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#define PTE_RPN_MAX (1UL << (64 - PTE_RPN_SHIFT))
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#define PTE_RPN_MASK (~((1UL<<PTE_RPN_SHIFT)-1))
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/* _PAGE_CHG_MASK masks of bits that are to be preserved accross
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* pgprot changes
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*/
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#define _PAGE_CHG_MASK (PTE_RPN_MASK | _PAGE_HPTEFLAGS | _PAGE_DIRTY | \
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_PAGE_ACCESSED)
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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 0x1ff
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/* Bits to mask out from a PGD/PUD to get to the PMD page */
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#define PUD_MASKED_BITS 0x1ff
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#ifndef __ASSEMBLY__
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/* Manipulate "rpte" values */
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#define __real_pte(e,p) ((real_pte_t) { \
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(e), pte_val(*((p) + PTRS_PER_PTE)) })
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#define __rpte_to_hidx(r,index) ((pte_val((r).pte) & _PAGE_COMBO) ? \
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(((r).hidx >> ((index)<<2)) & 0xf) : ((pte_val((r).pte) >> 12) & 0xf))
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#define __rpte_to_pte(r) ((r).pte)
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#define __rpte_sub_valid(rpte, index) \
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(pte_val(rpte.pte) & (_PAGE_HPTE_SUB0 >> (index)))
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/* Trick: we set __end to va + 64k, which happens works for
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* a 16M page as well as we want only one iteration
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*/
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#define pte_iterate_hashed_subpages(rpte, psize, va, index, shift) \
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do { \
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unsigned long __end = va + PAGE_SIZE; \
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unsigned __split = (psize == MMU_PAGE_4K || \
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psize == MMU_PAGE_64K_AP); \
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shift = mmu_psize_defs[psize].shift; \
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for (index = 0; va < __end; index++, va += (1 << shift)) { \
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if (!__split || __rpte_sub_valid(rpte, index)) do { \
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#define pte_iterate_hashed_end() } while(0); } } while(0)
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#define pte_pagesize_index(pte) \
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(((pte) & _PAGE_COMBO)? MMU_PAGE_4K: MMU_PAGE_64K)
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#endif /* __ASSEMBLY__ */
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_PGTABLE_64K_H */
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