From ca827d55ebaa24de9fca36ee24e42d6fc5119ee3 Mon Sep 17 00:00:00 2001 From: Khalid Aziz Date: Wed, 21 Feb 2018 10:15:44 -0700 Subject: [PATCH] mm, swap: Add infrastructure for saving page metadata on swap If a processor supports special metadata for a page, for example ADI version tags on SPARC M7, this metadata must be saved when the page is swapped out. The same metadata must be restored when the page is swapped back in. This patch adds two new architecture specific functions - arch_do_swap_page() to be called when a page is swapped in, and arch_unmap_one() to be called when a page is being unmapped for swap out. These architecture hooks allow page metadata to be saved if the architecture supports it. Signed-off-by: Khalid Aziz Cc: Khalid Aziz Acked-by: Jerome Marchand Reviewed-by: Anthony Yznaga Acked-by: Andrew Morton Signed-off-by: David S. Miller --- include/asm-generic/pgtable.h | 36 +++++++++++++++++++++++++++++++++++ mm/memory.c | 1 + mm/rmap.c | 14 ++++++++++++++ 3 files changed, 51 insertions(+) diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index 2cfa3075d148..6fbbc0b6c05e 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -400,6 +400,42 @@ static inline int pud_same(pud_t pud_a, pud_t pud_b) #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ #endif +#ifndef __HAVE_ARCH_DO_SWAP_PAGE +/* + * Some architectures support metadata associated with a page. When a + * page is being swapped out, this metadata must be saved so it can be + * restored when the page is swapped back in. SPARC M7 and newer + * processors support an ADI (Application Data Integrity) tag for the + * page as metadata for the page. arch_do_swap_page() can restore this + * metadata when a page is swapped back in. + */ +static inline void arch_do_swap_page(struct mm_struct *mm, + struct vm_area_struct *vma, + unsigned long addr, + pte_t pte, pte_t oldpte) +{ + +} +#endif + +#ifndef __HAVE_ARCH_UNMAP_ONE +/* + * Some architectures support metadata associated with a page. When a + * page is being swapped out, this metadata must be saved so it can be + * restored when the page is swapped back in. SPARC M7 and newer + * processors support an ADI (Application Data Integrity) tag for the + * page as metadata for the page. arch_unmap_one() can save this + * metadata on a swap-out of a page. + */ +static inline int arch_unmap_one(struct mm_struct *mm, + struct vm_area_struct *vma, + unsigned long addr, + pte_t orig_pte) +{ + return 0; +} +#endif + #ifndef __HAVE_ARCH_PGD_OFFSET_GATE #define pgd_offset_gate(mm, addr) pgd_offset(mm, addr) #endif diff --git a/mm/memory.c b/mm/memory.c index 5fcfc24904d1..aed37325d94e 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3053,6 +3053,7 @@ int do_swap_page(struct vm_fault *vmf) if (pte_swp_soft_dirty(vmf->orig_pte)) pte = pte_mksoft_dirty(pte); set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); + arch_do_swap_page(vma->vm_mm, vma, vmf->address, pte, vmf->orig_pte); vmf->orig_pte = pte; /* ksm created a completely new copy */ diff --git a/mm/rmap.c b/mm/rmap.c index 47db27f8049e..144c66e688a9 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1497,6 +1497,14 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, (flags & (TTU_MIGRATION|TTU_SPLIT_FREEZE))) { swp_entry_t entry; pte_t swp_pte; + + if (arch_unmap_one(mm, vma, address, pteval) < 0) { + set_pte_at(mm, address, pvmw.pte, pteval); + ret = false; + page_vma_mapped_walk_done(&pvmw); + break; + } + /* * Store the pfn of the page in a special migration * pte. do_swap_page() will wait until the migration @@ -1556,6 +1564,12 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, page_vma_mapped_walk_done(&pvmw); break; } + if (arch_unmap_one(mm, vma, address, pteval) < 0) { + set_pte_at(mm, address, pvmw.pte, pteval); + ret = false; + page_vma_mapped_walk_done(&pvmw); + break; + } if (list_empty(&mm->mmlist)) { spin_lock(&mmlist_lock); if (list_empty(&mm->mmlist)) -- GitLab