[RFC v5 26/38] powerpc: check key protection for user page access

[Ram Pai]

Make sure that the kernel does not access user pages without
checking their key-protection.

Signed-off-by: Ram Pai <linuxram at us.ibm.com>
---
 arch/powerpc/include/asm/book3s/64/pgtable.h |   14 ++++++++++++++
 1 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index aad205c..d590f30 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -476,6 +476,20 @@ static inline void write_uamor(u64 value)
 
 extern bool arch_pte_access_permitted(u64 pte, bool write, bool execute);
 
+#define pte_access_permitted(pte, write) \
+	(pte_present(pte) && \
+	 ((!(write) || pte_write(pte)) && \
+	  arch_pte_access_permitted(pte_val(pte), !!write, 0)))
+
+/*
+ * We store key in pmd for huge tlb pages. So need
+ * to check for key protection.
+ */
+#define pmd_access_permitted(pmd, write) \
+	(pmd_present(pmd) && \
+	 ((!(write) || pmd_write(pmd)) && \
+	  arch_pte_access_permitted(pmd_val(pmd), !!write, 0)))
+
 #else /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
 
 static inline u64 read_amr(void)
-- 
1.7.1