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author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-03-10 08:59:07 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-03-10 08:59:07 -0800 |
commit | baeedc7158da5b0f489d04125ba6adfba532a6f7 (patch) | |
tree | 1f42b5cd4a961ed10673578a28602dd13d09ab99 /mm/gup.c | |
parent | 8fe3ccaed080a7804bc459c42e0419253973be92 (diff) | |
parent | 90eceff1a375f6ffa78caf8654e787c0a8a591ef (diff) | |
download | linux-stable-baeedc7158da5b0f489d04125ba6adfba532a6f7.tar.gz linux-stable-baeedc7158da5b0f489d04125ba6adfba532a6f7.tar.bz2 linux-stable-baeedc7158da5b0f489d04125ba6adfba532a6f7.zip |
Merge branch 'prep-for-5level'
Merge 5-level page table prep from Kirill Shutemov:
"Here's relatively low-risk part of 5-level paging patchset. Merging it
now will make x86 5-level paging enabling in v4.12 easier.
The first patch is actually x86-specific: detect 5-level paging
support. It boils down to single define.
The rest of patchset converts Linux MMU abstraction from 4- to 5-level
paging.
Enabling of new abstraction in most cases requires adding single line
of code in arch-specific code. The rest is taken care by asm-generic/.
Changes to mm/ code are mostly mechanical: add support for new page
table level -- p4d_t -- where we deal with pud_t now.
v2:
- fix build on microblaze (Michal);
- comment for __ARCH_HAS_5LEVEL_HACK in kasan_populate_zero_shadow();
- acks from Michal"
* emailed patches from Kirill A Shutemov <kirill.shutemov@linux.intel.com>:
mm: introduce __p4d_alloc()
mm: convert generic code to 5-level paging
asm-generic: introduce <asm-generic/pgtable-nop4d.h>
arch, mm: convert all architectures to use 5level-fixup.h
asm-generic: introduce __ARCH_USE_5LEVEL_HACK
asm-generic: introduce 5level-fixup.h
x86/cpufeature: Add 5-level paging detection
Diffstat (limited to 'mm/gup.c')
-rw-r--r-- | mm/gup.c | 46 |
1 files changed, 40 insertions, 6 deletions
@@ -226,6 +226,7 @@ struct page *follow_page_mask(struct vm_area_struct *vma, unsigned int *page_mask) { pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pmd_t *pmd; spinlock_t *ptl; @@ -243,8 +244,13 @@ struct page *follow_page_mask(struct vm_area_struct *vma, pgd = pgd_offset(mm, address); if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) return no_page_table(vma, flags); - - pud = pud_offset(pgd, address); + p4d = p4d_offset(pgd, address); + if (p4d_none(*p4d)) + return no_page_table(vma, flags); + BUILD_BUG_ON(p4d_huge(*p4d)); + if (unlikely(p4d_bad(*p4d))) + return no_page_table(vma, flags); + pud = pud_offset(p4d, address); if (pud_none(*pud)) return no_page_table(vma, flags); if (pud_huge(*pud) && vma->vm_flags & VM_HUGETLB) { @@ -325,6 +331,7 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address, struct page **page) { pgd_t *pgd; + p4d_t *p4d; pud_t *pud; pmd_t *pmd; pte_t *pte; @@ -338,7 +345,9 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address, else pgd = pgd_offset_gate(mm, address); BUG_ON(pgd_none(*pgd)); - pud = pud_offset(pgd, address); + p4d = p4d_offset(pgd, address); + BUG_ON(p4d_none(*p4d)); + pud = pud_offset(p4d, address); BUG_ON(pud_none(*pud)); pmd = pmd_offset(pud, address); if (pmd_none(*pmd)) @@ -1400,13 +1409,13 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end, return 1; } -static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end, +static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end, int write, struct page **pages, int *nr) { unsigned long next; pud_t *pudp; - pudp = pud_offset(&pgd, addr); + pudp = pud_offset(&p4d, addr); do { pud_t pud = READ_ONCE(*pudp); @@ -1428,6 +1437,31 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end, return 1; } +static int gup_p4d_range(pgd_t pgd, unsigned long addr, unsigned long end, + int write, struct page **pages, int *nr) +{ + unsigned long next; + p4d_t *p4dp; + + p4dp = p4d_offset(&pgd, addr); + do { + p4d_t p4d = READ_ONCE(*p4dp); + + next = p4d_addr_end(addr, end); + if (p4d_none(p4d)) + return 0; + BUILD_BUG_ON(p4d_huge(p4d)); + if (unlikely(is_hugepd(__hugepd(p4d_val(p4d))))) { + if (!gup_huge_pd(__hugepd(p4d_val(p4d)), addr, + P4D_SHIFT, next, write, pages, nr)) + return 0; + } else if (!gup_p4d_range(p4d, addr, next, write, pages, nr)) + return 0; + } while (p4dp++, addr = next, addr != end); + + return 1; +} + /* * Like get_user_pages_fast() except it's IRQ-safe in that it won't fall back to * the regular GUP. It will only return non-negative values. @@ -1478,7 +1512,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, if (!gup_huge_pd(__hugepd(pgd_val(pgd)), addr, PGDIR_SHIFT, next, write, pages, &nr)) break; - } else if (!gup_pud_range(pgd, addr, next, write, pages, &nr)) + } else if (!gup_p4d_range(pgd, addr, next, write, pages, &nr)) break; } while (pgdp++, addr = next, addr != end); local_irq_restore(flags); |