diff options
Diffstat (limited to 'include/asm-generic/tlb.h')
| -rw-r--r-- | include/asm-generic/tlb.h | 60 |
1 files changed, 40 insertions, 20 deletions
diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index d1adfba8387e..1fff717cae51 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -58,6 +58,11 @@ * Defaults to flushing at tlb_end_vma() to reset the range; helps when * there's large holes between the VMAs. * + * - tlb_free_vmas() + * + * tlb_free_vmas() marks the start of unlinking of one or more vmas + * and freeing page-tables. + * * - tlb_remove_table() * * tlb_remove_table() is the basic primitive to free page-table directories @@ -227,10 +232,10 @@ static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page); */ static inline void tlb_remove_table(struct mmu_gather *tlb, void *table) { - struct page *page = (struct page *)table; + struct ptdesc *ptdesc = (struct ptdesc *)table; - pagetable_dtor(page_ptdesc(page)); - tlb_remove_page(tlb, page); + pagetable_dtor(ptdesc); + tlb_remove_page(tlb, ptdesc_page(ptdesc)); } #endif /* CONFIG_MMU_GATHER_TABLE_FREE */ @@ -464,7 +469,12 @@ tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) */ tlb->vma_huge = is_vm_hugetlb_page(vma); tlb->vma_exec = !!(vma->vm_flags & VM_EXEC); - tlb->vma_pfn = !!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)); + + /* + * Track if there's at least one VM_PFNMAP/VM_MIXEDMAP vma + * in the tracked range, see tlb_free_vmas(). + */ + tlb->vma_pfn |= !!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)); } static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) @@ -493,17 +503,11 @@ static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page) return tlb_remove_page_size(tlb, page, PAGE_SIZE); } -static inline void tlb_remove_ptdesc(struct mmu_gather *tlb, void *pt) +static inline void tlb_remove_ptdesc(struct mmu_gather *tlb, struct ptdesc *pt) { tlb_remove_table(tlb, pt); } -/* Like tlb_remove_ptdesc, but for page-like page directories. */ -static inline void tlb_remove_page_ptdesc(struct mmu_gather *tlb, struct ptdesc *pt) -{ - tlb_remove_page(tlb, ptdesc_page(pt)); -} - static inline void tlb_change_page_size(struct mmu_gather *tlb, unsigned int page_size) { @@ -554,22 +558,38 @@ static inline void tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct * static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma) { + if (tlb->fullmm || IS_ENABLED(CONFIG_MMU_GATHER_MERGE_VMAS)) + return; + + /* + * Do a TLB flush and reset the range at VMA boundaries; this avoids + * the ranges growing with the unused space between consecutive VMAs, + * but also the mmu_gather::vma_* flags from tlb_start_vma() rely on + * this. + */ + tlb_flush_mmu_tlbonly(tlb); +} + +static inline void tlb_free_vmas(struct mmu_gather *tlb) +{ if (tlb->fullmm) return; /* * VM_PFNMAP is more fragile because the core mm will not track the - * page mapcount -- there might not be page-frames for these PFNs after - * all. Force flush TLBs for such ranges to avoid munmap() vs - * unmap_mapping_range() races. + * page mapcount -- there might not be page-frames for these PFNs + * after all. + * + * Specifically() there is a race between munmap() and + * unmap_mapping_range(), where munmap() will unlink the VMA, such + * that unmap_mapping_range() will no longer observe the VMA and + * no-op, without observing the TLBI, returning prematurely. + * + * So if we're about to unlink such a VMA, and we have pending + * TLBI for such a vma, flush things now. */ - if (tlb->vma_pfn || !IS_ENABLED(CONFIG_MMU_GATHER_MERGE_VMAS)) { - /* - * Do a TLB flush and reset the range at VMA boundaries; this avoids - * the ranges growing with the unused space between consecutive VMAs. - */ + if (tlb->vma_pfn) tlb_flush_mmu_tlbonly(tlb); - } } /* |