Nicholas Piggin [off-list ref] writes:

On Thu, 28 Jul 2016 00:18:06 +1000
Michael Ellerman [off-list ref] wrote:

quoted

diff --git a/arch/powerpc/include/asm/mmu.h

b/arch/powerpc/include/asm/mmu.h index eb942a446969..f413b3213a3b
100644 --- a/arch/powerpc/include/asm/mmu.h

+++ b/arch/powerpc/include/asm/mmu.h

@@ -163,6 +163,18 @@ static inline void assert_pte_locked(struct

mm_struct *mm, unsigned long addr) }
 #endif /* !CONFIG_DEBUG_VM */
 
+#ifdef CONFIG_PPC_RADIX_MMU
+static inline bool radix_enabled(void)
+{
+	return mmu_has_feature(MMU_FTR_TYPE_RADIX);
+}
+#else
+static inline bool radix_enabled(void)
+{
+	return false;
+}
+#endif

Won't MMU_FTRS_POSSIBLE just do the right thing when
!CONFIG_PPC_RADIX_MMU?

Yes it should.

I'll have to work out why Aneesh thought he needed to do it explicitly
and whether that is needed or not.

cheers