Page table checking depends on architectures providing an implementation of p{te,md,ud}_user_accessible_page. With refactorisations made on powerpc/mm, the pte_access_permitted() and similar methods verify whether a userland page is accessible with the required permissions. Since page table checking is the only user of p{te,md,ud}_user_accessible_page(), implement these for all platforms, using some of the same preliminary checks taken by pte_access_permitted() on that platform. Since Commit 8e9bd41e4ce1 ("powerpc/nohash: Replace pte_user() by pte_read()") pte_user() is no longer required to be present on all platforms as it may be equivalent to or implied by pte_read(). Hence implementations of pte_user_accessible_page() are specialised. Signed-off-by: Rohan McLure <rmclure@xxxxxxxxxxxxx> --- v9: New implementation v10: Let book3s/64 use pte_user(), but otherwise default other platforms to using the address provided with the call to infer whether it is a user page or not. pmd/pud variants will warn on all other platforms, as they should not be used for user page mappings v11: Conditionally define p{m,u}d_user_accessible_page(), as not all platforms have p{m,u}d_leaf(), p{m,u}d_pte() stubs. --- arch/powerpc/include/asm/book3s/32/pgtable.h | 5 +++++ arch/powerpc/include/asm/book3s/64/pgtable.h | 17 +++++++++++++++++ arch/powerpc/include/asm/nohash/pgtable.h | 5 +++++ arch/powerpc/include/asm/pgtable.h | 8 ++++++++ 4 files changed, 35 insertions(+) diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h index 52971ee30717..83f7b98ef49f 100644 --- a/arch/powerpc/include/asm/book3s/32/pgtable.h +++ b/arch/powerpc/include/asm/book3s/32/pgtable.h @@ -436,6 +436,11 @@ static inline bool pte_access_permitted(pte_t pte, bool write) return true; } +static inline bool pte_user_accessible_page(pte_t pte, unsigned long addr) +{ + return pte_present(pte) && !is_kernel_addr(addr); +} + /* Conversion functions: convert a page and protection to a page entry, * and a page entry and page directory to the page they refer to. * diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index fac5615e6bc5..d8640ddbcad1 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -538,6 +538,11 @@ static inline bool pte_access_permitted(pte_t pte, bool write) return arch_pte_access_permitted(pte_val(pte), write, 0); } +static inline bool pte_user_accessible_page(pte_t pte, unsigned long addr) +{ + return pte_present(pte) && pte_user(pte); +} + /* * Conversion functions: convert a page and protection to a page entry, * and a page entry and page directory to the page they refer to. @@ -1441,5 +1446,17 @@ static inline bool pud_leaf(pud_t pud) return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE)); } +#define pmd_user_accessible_page pmd_user_accessible_page +static inline bool pmd_user_accessible_page(pmd_t pmd, unsigned long addr) +{ + return pmd_leaf(pmd) && pte_user_accessible_page(pmd_pte(pmd), addr); +} + +#define pud_user_accessible_page pud_user_accessible_page +static inline bool pud_user_accessible_page(pud_t pud, unsigned long addr) +{ + return pud_leaf(pud) && pte_user_accessible_page(pud_pte(pud), addr); +} + #endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_BOOK3S_64_PGTABLE_H_ */ diff --git a/arch/powerpc/include/asm/nohash/pgtable.h b/arch/powerpc/include/asm/nohash/pgtable.h index 427db14292c9..413d01a51e6f 100644 --- a/arch/powerpc/include/asm/nohash/pgtable.h +++ b/arch/powerpc/include/asm/nohash/pgtable.h @@ -213,6 +213,11 @@ static inline bool pte_access_permitted(pte_t pte, bool write) return true; } +static inline bool pte_user_accessible_page(pte_t pte, unsigned long addr) +{ + return pte_present(pte) && !is_kernel_addr(addr); +} + /* Conversion functions: convert a page and protection to a page entry, * and a page entry and page directory to the page they refer to. * diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h index baa2c4cd35db..26be61b00259 100644 --- a/arch/powerpc/include/asm/pgtable.h +++ b/arch/powerpc/include/asm/pgtable.h @@ -220,6 +220,14 @@ static inline int pud_pfn(pud_t pud) } #endif +#ifndef pmd_user_accessible_page +#define pmd_user_accessible_page(pmd, addr) false +#endif + +#ifndef pud_user_accessible_page +#define pud_user_accessible_page(pud, addr) false +#endif + #endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_PGTABLE_H */ -- 2.44.0