[PATCH] ppc64: Fix runlatch code to work on pseries machines

Not all ppc64 CPUs have the CTRL SPR, so we need a cputable feature for it.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/ppc64/kernel/cputable.c

@@ -81,7 +81,7 @@ struct cpu_spec	cpu_specs[] = {
 		.cpu_name		= "RS64-II (northstar)",
 		.cpu_features		= CPU_FTR_SPLIT_ID_CACHE |
 			CPU_FTR_USE_TB | CPU_FTR_HPTE_TABLE | CPU_FTR_IABR |
-			CPU_FTR_PMC8 | CPU_FTR_MMCRA,
+			CPU_FTR_PMC8 | CPU_FTR_MMCRA | CPU_FTR_CTRL,
 		.cpu_user_features	= COMMON_USER_PPC64,
 		.icache_bsize		= 128,
 		.dcache_bsize		= 128,
@@ -94,7 +94,7 @@ struct cpu_spec	cpu_specs[] = {
 		.cpu_name		= "RS64-III (pulsar)",
 		.cpu_features		= CPU_FTR_SPLIT_ID_CACHE |
 			CPU_FTR_USE_TB | CPU_FTR_HPTE_TABLE | CPU_FTR_IABR |
-			CPU_FTR_PMC8 | CPU_FTR_MMCRA,
+			CPU_FTR_PMC8 | CPU_FTR_MMCRA | CPU_FTR_CTRL,
 		.cpu_user_features	= COMMON_USER_PPC64,
 		.icache_bsize		= 128,
 		.dcache_bsize		= 128,
@@ -107,7 +107,7 @@ struct cpu_spec	cpu_specs[] = {
 		.cpu_name		= "RS64-III (icestar)",
 		.cpu_features		= CPU_FTR_SPLIT_ID_CACHE |
 			CPU_FTR_USE_TB | CPU_FTR_HPTE_TABLE | CPU_FTR_IABR |
-			CPU_FTR_PMC8 | CPU_FTR_MMCRA,
+			CPU_FTR_PMC8 | CPU_FTR_MMCRA | CPU_FTR_CTRL,
 		.cpu_user_features	= COMMON_USER_PPC64,
 		.icache_bsize		= 128,
 		.dcache_bsize		= 128,
@@ -120,7 +120,7 @@ struct cpu_spec	cpu_specs[] = {
 		.cpu_name		= "RS64-IV (sstar)",
 		.cpu_features		= CPU_FTR_SPLIT_ID_CACHE |
 			CPU_FTR_USE_TB | CPU_FTR_HPTE_TABLE | CPU_FTR_IABR |
-			CPU_FTR_PMC8 | CPU_FTR_MMCRA,
+			CPU_FTR_PMC8 | CPU_FTR_MMCRA | CPU_FTR_CTRL,
 		.cpu_user_features	= COMMON_USER_PPC64,
 		.icache_bsize		= 128,
 		.dcache_bsize		= 128,

include/asm-ppc64/cputable.h

@@ -138,6 +138,7 @@ extern firmware_feature_t firmware_features_table[];
 #define CPU_FTR_COHERENT_ICACHE  	ASM_CONST(0x0000020000000000)
 #define CPU_FTR_LOCKLESS_TLBIE		ASM_CONST(0x0000040000000000)
 #define CPU_FTR_MMCRA_SIHV		ASM_CONST(0x0000080000000000)
+#define CPU_FTR_CTRL			ASM_CONST(0x0000100000000000)
 
 /* Platform firmware features */
 #define FW_FTR_				ASM_CONST(0x0000000000000001)
@@ -148,7 +149,7 @@ extern firmware_feature_t firmware_features_table[];
 
 #define CPU_FTR_PPCAS_ARCH_V2_BASE (CPU_FTR_SLB | \
                                  CPU_FTR_TLBIEL | CPU_FTR_NOEXECUTE | \
-                                 CPU_FTR_NODSISRALIGN)
+                                 CPU_FTR_NODSISRALIGN | CPU_FTR_CTRL)
 
 /* iSeries doesn't support large pages */
 #ifdef CONFIG_PPC_ISERIES

include/asm-ppc64/processor.h

@@ -20,6 +20,7 @@
 #include <asm/ptrace.h>
 #include <asm/types.h>
 #include <asm/systemcfg.h>
+#include <asm/cputable.h>
 
 /* Machine State Register (MSR) Fields */
 #define MSR_SF_LG	63              /* Enable 64 bit mode */
@@ -501,18 +502,22 @@ static inline void ppc64_runlatch_on(void)
 {
 	unsigned long ctrl;
 
-	ctrl = mfspr(SPRN_CTRLF);
-	ctrl |= CTRL_RUNLATCH;
-	mtspr(SPRN_CTRLT, ctrl);
+	if (cpu_has_feature(CPU_FTR_CTRL)) {
+		ctrl = mfspr(SPRN_CTRLF);
+		ctrl |= CTRL_RUNLATCH;
+		mtspr(SPRN_CTRLT, ctrl);
+	}
 }
 
 static inline void ppc64_runlatch_off(void)
 {
 	unsigned long ctrl;
 
-	ctrl = mfspr(SPRN_CTRLF);
-	ctrl &= ~CTRL_RUNLATCH;
-	mtspr(SPRN_CTRLT, ctrl);
+	if (cpu_has_feature(CPU_FTR_CTRL)) {
+		ctrl = mfspr(SPRN_CTRLF);
+		ctrl &= ~CTRL_RUNLATCH;
+		mtspr(SPRN_CTRLT, ctrl);
+	}
 }
 
 #endif /* __KERNEL__ */