mm: replace pud_write with pud_access_permitted in fault + gup paths (e7fe7b5c) · Commits · 戴 / test

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. [dan.j.williams@intel.com: fix powerpc compile error] Link: http://lkml.kernel.org/r/151129127237.37405.16073414520854722485.stgit@dwillia2-desk3.amr.corp.intel.com Link: http://lkml.kernel.org/r/151043110453.2842.2166049702068628177.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by:

Dan Williams <dan.j.williams@intel.com> 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:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

arch/s390/include/asm/pgtable.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -1264,6 +1264,12 @@ static inline pud_t pud_mkwrite(pud_t pud)
		return pud;
		}

		#define pud_write 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)) {

arch/sparc/mm/gup.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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;

mm/huge_memory.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1019,7 +1019,7 @@ 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))

mm/memory.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -4013,7 +4013,7 @@ 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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