[PATCH v6 6/7] powerpc: mm: Add p{te,md,ud}_user_accessible_page helpers

[Rohan McLure <rmclure@linux.ibm.com>]

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

Also implement missing pud_user definitions for both Book3S/nohash 64-bit
systems, and pmd_user for Book3S/nohash 32-bit systems.

Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
---
V2: Provide missing pud_user implementations, use p{u,m}d_is_leaf.
V3: Provide missing pmd_user implementations as stubs in 32-bit.
V4: Use pmd_leaf, pud_leaf, and define pmd_user for 32 Book3E with
static inline method rather than macro.
---
 arch/powerpc/include/asm/book3s/32/pgtable.h |  4 ++++
 arch/powerpc/include/asm/book3s/64/pgtable.h | 10 ++++++++++
 arch/powerpc/include/asm/nohash/32/pgtable.h |  5 +++++
 arch/powerpc/include/asm/nohash/64/pgtable.h | 10 ++++++++++
 arch/powerpc/include/asm/pgtable.h           | 15 +++++++++++++++
 5 files changed, 44 insertions(+)

diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
index a090cb13a4a0..afd672e84791 100644
--- a/arch/powerpc/include/asm/book3s/32/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
@@ -516,6 +516,10 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 	return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
 }
 
+static inline bool pmd_user(pmd_t pmd)
+{
+	return 0;
+}
 
 
 /* This low level function performs the actual PTE insertion
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 8bbd3e1df93e..93601ef4c665 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -538,6 +538,16 @@ static inline bool pte_user(pte_t pte)
 	return !(pte_raw(pte) & cpu_to_be64(_PAGE_PRIVILEGED));
 }
 
+static inline bool pmd_user(pmd_t pmd)
+{
+	return !(pmd_raw(pmd) & cpu_to_be64(_PAGE_PRIVILEGED));
+}
+
+static inline bool pud_user(pud_t pud)
+{
+	return !(pud_raw(pud) & cpu_to_be64(_PAGE_PRIVILEGED));
+}
+
 #define pte_access_permitted pte_access_permitted
 static inline bool pte_access_permitted(pte_t pte, bool write)
 {
diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h
index 70edad44dff6..d953533c56ff 100644
--- a/arch/powerpc/include/asm/nohash/32/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
@@ -209,6 +209,11 @@ static inline void pmd_clear(pmd_t *pmdp)
 	*pmdp = __pmd(0);
 }
 
+static inline bool pmd_user(pmd_t pmd)
+{
+	return false;
+}
+
 /*
  * PTE updates. This function is called whenever an existing
  * valid PTE is updated. This does -not- include set_pte_at()
diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h b/arch/powerpc/include/asm/nohash/64/pgtable.h
index d391a45e0f11..14e69ebad31f 100644
--- a/arch/powerpc/include/asm/nohash/64/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/64/pgtable.h
@@ -123,6 +123,11 @@ static inline pte_t pmd_pte(pmd_t pmd)
 	return __pte(pmd_val(pmd));
 }
 
+static inline bool pmd_user(pmd_t pmd)
+{
+	return (pmd_val(pmd) & _PAGE_USER) == _PAGE_USER;
+}
+
 #define pmd_none(pmd)		(!pmd_val(pmd))
 #define	pmd_bad(pmd)		(!is_kernel_addr(pmd_val(pmd)) \
 				 || (pmd_val(pmd) & PMD_BAD_BITS))
@@ -164,6 +169,11 @@ static inline pte_t pud_pte(pud_t pud)
 	return __pte(pud_val(pud));
 }
 
+static inline bool pud_user(pud_t pud)
+{
+	return (pud_val(pud) & _PAGE_USER) == _PAGE_USER;
+}
+
 static inline pud_t pte_pud(pte_t pte)
 {
 	return __pud(pte_val(pte));
diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index ad0829f816e9..b76fdb80b6c9 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -167,6 +167,21 @@ static inline int pud_pfn(pud_t pud)
 }
 #endif
 
+static inline bool pte_user_accessible_page(pte_t pte)
+{
+	return pte_present(pte) && pte_user(pte);
+}
+
+static inline bool pmd_user_accessible_page(pmd_t pmd)
+{
+	return pmd_leaf(pmd) && pmd_present(pmd) && pmd_user(pmd);
+}
+
+static inline bool pud_user_accessible_page(pud_t pud)
+{
+	return pud_leaf(pud) && pud_present(pud) && pud_user(pud);
+}
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_POWERPC_PGTABLE_H */
-- 
2.37.2