[PATCH 1/2] powerpc: Add mask of possible MMU features

[Michael Ellerman <mpe@ellerman.id.au>]

Follow the example of the cpu feature code, and add a mask of possible
MMU features, MMU_FTRS_POSSIBLE.

This is used in mmu_has_feature(), which allows the possible mask to act
as a shortcut for any features that are not possible, but still allows
the feature bit itself to be defined.

We will use this feature in the next commit to fix a bug with the
recently add MMU_FTR_RADIX.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/include/asm/mmu.h | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
index d91dc886c90f..a5e37c93700b 100644
--- a/arch/powerpc/include/asm/mmu.h
+++ b/arch/powerpc/include/asm/mmu.h
@@ -119,9 +119,21 @@
 DECLARE_PER_CPU(int, next_tlbcam_idx);
 #endif
 
+enum {
+	MMU_FTRS_POSSIBLE = MMU_FTR_HPTE_TABLE | MMU_FTR_TYPE_8xx |
+		MMU_FTR_TYPE_40x | MMU_FTR_TYPE_44x | MMU_FTR_TYPE_FSL_E |
+		MMU_FTR_TYPE_47x | MMU_FTR_USE_HIGH_BATS | MMU_FTR_BIG_PHYS |
+		MMU_FTR_USE_TLBIVAX_BCAST | MMU_FTR_USE_TLBILX |
+		MMU_FTR_LOCK_BCAST_INVAL | MMU_FTR_NEED_DTLB_SW_LRU |
+		MMU_FTR_USE_TLBRSRV | MMU_FTR_USE_PAIRED_MAS |
+		MMU_FTR_NO_SLBIE_B | MMU_FTR_16M_PAGE | MMU_FTR_TLBIEL |
+		MMU_FTR_LOCKLESS_TLBIE | MMU_FTR_CI_LARGE_PAGE |
+		MMU_FTR_1T_SEGMENT | MMU_FTR_RADIX,
+};
+
 static inline int mmu_has_feature(unsigned long feature)
 {
-	return (cur_cpu_spec->mmu_features & feature);
+	return (MMU_FTRS_POSSIBLE & cur_cpu_spec->mmu_features & feature);
 }
 
 static inline void mmu_clear_feature(unsigned long feature)
-- 
2.5.0