powerpc/pseries: Add page coalescing support

Adds support for page coalescing, which is a feature on IBM Power servers
which allows for coalescing identical pages between logical partitions.
Hint text pages as coalesce candidates, since they are the most likely
pages to be able to be coalesced between partitions. This patch also
exports some page coalescing statistics available from firmware via
lparcfg.

[BenH: Moved a couple of things around to fix compile problems]

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/firmware.h b/arch/powerpc/include/asm/firmware.h
index 4ef662e..3a6c586 100644
--- a/arch/powerpc/include/asm/firmware.h
+++ b/arch/powerpc/include/asm/firmware.h
@@ -47,6 +47,7 @@
 #define FW_FEATURE_BEAT		ASM_CONST(0x0000000001000000)
 #define FW_FEATURE_CMO		ASM_CONST(0x0000000002000000)
 #define FW_FEATURE_VPHN		ASM_CONST(0x0000000004000000)
+#define FW_FEATURE_XCMO		ASM_CONST(0x0000000008000000)
 
 #ifndef __ASSEMBLY__
 
@@ -60,7 +61,7 @@
 		FW_FEATURE_VIO | FW_FEATURE_RDMA | FW_FEATURE_LLAN |
 		FW_FEATURE_BULK_REMOVE | FW_FEATURE_XDABR |
 		FW_FEATURE_MULTITCE | FW_FEATURE_SPLPAR | FW_FEATURE_LPAR |
-		FW_FEATURE_CMO | FW_FEATURE_VPHN,
+		FW_FEATURE_CMO | FW_FEATURE_VPHN | FW_FEATURE_XCMO,
 	FW_FEATURE_PSERIES_ALWAYS = 0,
 	FW_FEATURE_ISERIES_POSSIBLE = FW_FEATURE_ISERIES | FW_FEATURE_LPAR,
 	FW_FEATURE_ISERIES_ALWAYS = FW_FEATURE_ISERIES | FW_FEATURE_LPAR,