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 preliminay 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 are
specialised.
Signed-off-by: Rohan McLure <rmcl...@linux.ibm.com>
---
v9: New implementation
---
arch/powerpc/include/asm/book3s/32/pgtable.h | 5 +++++
arch/powerpc/include/asm/book3s/64/pgtable.h | 5 +++++
arch/powerpc/include/asm/nohash/pgtable.h | 5 +++++
arch/powerpc/include/asm/pgtable.h | 15 +++++++++++++++
4 files changed, 30 insertions(+)
diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h
b/arch/powerpc/include/asm/book3s/32/pgtable.h
index 9cc95a61d2a6..bd6f8cdd25aa 100644
--- a/arch/powerpc/include/asm/book3s/32/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
@@ -441,6 +441,11 @@ static inline bool pte_access_permitted(pte_t pte, bool
write)
return true;
}
+static inline bool pte_user_accessible_page(pte_t pte)
+{
+ return pte_present(pte) && pte_read(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.
*
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h
b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 2454174b26cb..dd3e7b190ab7 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -544,6 +544,11 @@ 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)
+{
+ return pte_present(pte) && pte_user(pte) && pte_read(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.
diff --git a/arch/powerpc/include/asm/nohash/pgtable.h
b/arch/powerpc/include/asm/nohash/pgtable.h
index 427db14292c9..33b4a4267f66 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)
+{
+ return pte_present(pte) && pte_read(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.
*
diff --git a/arch/powerpc/include/asm/pgtable.h
b/arch/powerpc/include/asm/pgtable.h
index d7d0f47760d3..661bf3afca37 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -250,6 +250,21 @@ static inline pte_t pud_pte(pud_t pud)
return __pte(pud_val(pud));
}
#endif
+
+static inline bool pmd_user_accessible_page(pmd_t pmd)
+{
+ pte_t pte = pmd_pte(pmd);
+
+ return pte_user_accessible_page(pte);
+}
+
+static inline bool pud_user_accessible_page(pud_t pud)
+{
+ pte_t pte = pud_pte(pud);
+
+ return pte_user_accessible_page(pte);
+}
+
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_PGTABLE_H */
--
2.43.0
