forked from Minki/linux
a4fe3ce769
Currently each available hugepage size uses a slightly different pagetable layout: that is, the bottem level table of pointers to hugepages is a different size, and may branch off from the normal page tables at a different level. Every hugepage aware path that needs to walk the pagetables must therefore look up the hugepage size from the slice info first, and work out the correct way to walk the pagetables accordingly. Future hardware is likely to add more possible hugepage sizes, more layout options and more mess. This patch, therefore reworks the handling of hugepage pagetables to reduce this complexity. In the new scheme, instead of having to consult the slice mask, pagetable walking code can check a flag in the PGD/PUD/PMD entries to see where to branch off to hugepage pagetables, and the entry also contains the information (eseentially hugepage shift) necessary to then interpret that table without recourse to the slice mask. This scheme can be extended neatly to handle multiple levels of self-describing "special" hugepage pagetables, although for now we assume only one level exists. This approach means that only the pagetable allocation path needs to know how the pagetables should be set out. All other (hugepage) pagetable walking paths can just interpret the structure as they go. There already was a flag bit in PGD/PUD/PMD entries for hugepage directory pointers, but it was only used for debug. We alter that flag bit to instead be a 0 in the MSB to indicate a hugepage pagetable pointer (normally it would be 1 since the pointer lies in the linear mapping). This means that asm pagetable walking can test for (and punt on) hugepage pointers with the same test that checks for unpopulated page directory entries (beq becomes bge), since hugepage pointers will always be positive, and normal pointers always negative. While we're at it, we get rid of the confusing (and grep defeating) #defining of hugepte_shift to be the same thing as mmu_huge_psizes. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
81 lines
1.8 KiB
C
81 lines
1.8 KiB
C
#ifndef _ASM_POWERPC_HUGETLB_H
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#define _ASM_POWERPC_HUGETLB_H
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#include <asm/page.h>
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int is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
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unsigned long len);
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void hugetlb_free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
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unsigned long end, unsigned long floor,
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unsigned long ceiling);
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void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
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pte_t *ptep, pte_t pte);
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pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
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pte_t *ptep);
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/*
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* The version of vma_mmu_pagesize() in arch/powerpc/mm/hugetlbpage.c needs
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* to override the version in mm/hugetlb.c
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*/
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#define vma_mmu_pagesize vma_mmu_pagesize
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/*
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* If the arch doesn't supply something else, assume that hugepage
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* size aligned regions are ok without further preparation.
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*/
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static inline int prepare_hugepage_range(struct file *file,
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unsigned long addr, unsigned long len)
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{
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struct hstate *h = hstate_file(file);
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if (len & ~huge_page_mask(h))
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return -EINVAL;
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if (addr & ~huge_page_mask(h))
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return -EINVAL;
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return 0;
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}
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static inline void hugetlb_prefault_arch_hook(struct mm_struct *mm)
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{
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}
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static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
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unsigned long addr, pte_t *ptep)
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{
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}
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static inline int huge_pte_none(pte_t pte)
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{
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return pte_none(pte);
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}
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static inline pte_t huge_pte_wrprotect(pte_t pte)
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{
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return pte_wrprotect(pte);
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}
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static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma,
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unsigned long addr, pte_t *ptep,
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pte_t pte, int dirty)
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{
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return ptep_set_access_flags(vma, addr, ptep, pte, dirty);
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}
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static inline pte_t huge_ptep_get(pte_t *ptep)
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{
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return *ptep;
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}
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static inline int arch_prepare_hugepage(struct page *page)
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{
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return 0;
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}
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static inline void arch_release_hugepage(struct page *page)
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{
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}
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#endif /* _ASM_POWERPC_HUGETLB_H */
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