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author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2017-12-04 07:49:11 +0530 |
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committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-12-22 22:28:35 +1100 |
commit | f72a85e347810c76eb246e68751233aad3b84ac8 (patch) | |
tree | 8078274e912b95aecaa819848cb6a066896e2073 /arch/powerpc/include/asm/book3s | |
parent | 5fa5b16be5b319184378870467352eab6700b1de (diff) | |
download | linux-stable-f72a85e347810c76eb246e68751233aad3b84ac8.tar.gz linux-stable-f72a85e347810c76eb246e68751233aad3b84ac8.tar.bz2 linux-stable-f72a85e347810c76eb246e68751233aad3b84ac8.zip |
powerpc/mm/book3s/64: Add proper pte access check helper
pte_access_premitted get called in get_user_pages_fast path. If we
have marked the pte PROT_NONE, we should not allow a read access on
the address. With the current implementation we are not checking the
READ and only check for WRITE. This is needed on archs like ppc64 that
implement PROT_NONE using RWX access instead of _PAGE_PRESENT. Also
add pte_user check just to make sure we are not accessing kernel
mapping.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/include/asm/book3s')
-rw-r--r-- | arch/powerpc/include/asm/book3s/64/pgtable.h | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index 44697817ccc6..23b03449e2f1 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -546,6 +546,30 @@ static inline int pte_present(pte_t pte) { return !!(pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT)); } + +#define pte_access_permitted pte_access_permitted +static inline bool pte_access_permitted(pte_t pte, bool write) +{ + unsigned long pteval = pte_val(pte); + /* Also check for pte_user */ + unsigned long clear_pte_bits = _PAGE_PRIVILEGED; + /* + * _PAGE_READ is needed for any access and will be + * cleared for PROT_NONE + */ + unsigned long need_pte_bits = _PAGE_PRESENT | _PAGE_READ; + + if (write) + need_pte_bits |= _PAGE_WRITE; + + if ((pteval & need_pte_bits) != need_pte_bits) + return false; + + if ((pteval & clear_pte_bits) == clear_pte_bits) + return false; + return true; +} + /* * Conversion functions: convert a page and protection to a page entry, * and a page entry and page directory to the page they refer to. @@ -850,6 +874,11 @@ static inline int pud_bad(pud_t pud) return hash__pud_bad(pud); } +#define pud_access_permitted pud_access_permitted +static inline bool pud_access_permitted(pud_t pud, bool write) +{ + return pte_access_permitted(pud_pte(pud), write); +} #define pgd_write(pgd) pte_write(pgd_pte(pgd)) static inline void pgd_set(pgd_t *pgdp, unsigned long val) @@ -889,6 +918,12 @@ static inline int pgd_bad(pgd_t pgd) return hash__pgd_bad(pgd); } +#define pgd_access_permitted pgd_access_permitted +static inline bool pgd_access_permitted(pgd_t pgd, bool write) +{ + return pte_access_permitted(pgd_pte(pgd), write); +} + extern struct page *pgd_page(pgd_t pgd); /* Pointers in the page table tree are physical addresses */ @@ -1009,6 +1044,12 @@ static inline int pmd_protnone(pmd_t pmd) #define __pmd_write(pmd) __pte_write(pmd_pte(pmd)) #define pmd_savedwrite(pmd) pte_savedwrite(pmd_pte(pmd)) +#define pmd_access_permitted pmd_access_permitted +static inline bool pmd_access_permitted(pmd_t pmd, bool write) +{ + return pte_access_permitted(pmd_pte(pmd), write); +} + #ifdef CONFIG_TRANSPARENT_HUGEPAGE extern pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot); extern pmd_t mk_pmd(struct page *page, pgprot_t pgprot); |