Messages in this thread Patch in this message | | | Subject | [PATCH v2 2/4] mm: replace pud_write with pud_access_permitted in fault + gup paths | From | Dan Williams <> | Date | Sat, 11 Nov 2017 12:11:44 -0800 |
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The 'access_permitted' helper is used in the gup-fast path and goes beyond the simple _PAGE_RW check to also:
* validate that the mapping is writable from a protection keys standpoint
* validate that the pte has _PAGE_USER set since all fault paths where pud_write is must be referencing user-memory.
Cc: Dave Hansen <dave.hansen@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- arch/s390/include/asm/pgtable.h | 6 ++++++ arch/sparc/mm/gup.c | 2 +- mm/huge_memory.c | 2 +- mm/memory.c | 2 +- 4 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index d7fe9838084d..1f36a01e22f6 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -1264,6 +1264,12 @@ static inline pud_t pud_mkwrite(pud_t pud) return pud; } +#define __HAVE_ARCH_PUD_WRITE +static inline int pud_write(pud_t pud) +{ + return (pud_val(pud) & _REGION3_ENTRY_WRITE) != 0; +} + static inline pud_t pud_mkclean(pud_t pud) { if (pud_large(pud)) { diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c index 5335ba3c850e..5ae2d0a01a70 100644 --- a/arch/sparc/mm/gup.c +++ b/arch/sparc/mm/gup.c @@ -114,7 +114,7 @@ static int gup_huge_pud(pud_t *pudp, pud_t pud, unsigned long addr, if (!(pud_val(pud) & _PAGE_VALID)) return 0; - if (write && !pud_write(pud)) + if (!pud_access_permitted(pud, write)) return 0; refs = 0; diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 1981ed697dab..1e4e11275856 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1022,7 +1022,7 @@ struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr, assert_spin_locked(pud_lockptr(mm, pud)); - if (flags & FOLL_WRITE && !pud_write(*pud)) + if (!pud_access_permitted(*pud, flags & FOLL_WRITE)) return NULL; if (pud_present(*pud) && pud_devmap(*pud)) diff --git a/mm/memory.c b/mm/memory.c index a728bed16c20..64f86beadcca 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3987,7 +3987,7 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address, /* NUMA case for anonymous PUDs would go here */ - if (dirty && !pud_write(orig_pud)) { + if (dirty && !pud_access_permitted(orig_pud, WRITE)) { ret = wp_huge_pud(&vmf, orig_pud); if (!(ret & VM_FAULT_FALLBACK)) return ret;
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