Add the following helpers for detecting whether a page table entry
is a leaf and is accessible to user space.
* pte_user_accessible_page
* pmd_user_accessible_page
* pud_user_accessible_page
The heavy lifting is done by pte_user, which checks user accessibility
on a per-mmu level, provided prior to this commit.
On 32-bit systems, provide stub implementations for these methods, with
BUG(), as debug features such as page table checks will emit functions
that call p{md,ud}_user_accessible_page but must not be used.
Signed-off-by: Rohan McLure <rmcl...@linux.ibm.com>
---
arch/powerpc/include/asm/pgtable.h | 35 ++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)
diff --git a/arch/powerpc/include/asm/pgtable.h
b/arch/powerpc/include/asm/pgtable.h
index 522145b16a07..8c1f5feb9360 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -170,6 +170,41 @@ static inline int pud_pfn(pud_t pud)
return 0;
}
+static inline bool pte_user_accessible_page(pte_t pte)
+{
+ return (pte_val(pte) & _PAGE_PRESENT) && pte_user(pte);
+}
+
+#ifdef CONFIG_PPC64
+
+static inline bool pmd_user_accessible_page(pmd_t pmd)
+{
+ return pmd_is_leaf(pmd) && pmd_present(pmd)
+ && pte_user(pmd_pte(pmd));
+}
+
+static inline bool pud_user_accessible_page(pud_t pud)
+{
+ return pud_is_leaf(pud) && pud_present(pud)
+ && pte_user(pud_pte(pud));
+}
+
+#else
+
+static inline bool pmd_user_accessible_page(pmd_t pmd)
+{
+ BUG();
+ return false;
+}
+
+static inline bool pud_user_accessible_page(pud_t pud)
+{
+ BUG();
+ return false;
+}
+
+#endif /* CONFIG_PPC64 */
+
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_PGTABLE_H */
--
2.34.1
