@@ -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.
*
@@ -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_ */
@@ -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.
*
@@ -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 */
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@linux.ibm.com> --- 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(+)