[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>

2 files changed, 13 insertions, 7 deletions

diff --git a/include/asm-ppc64/cputable.h b/include/asm-ppc64/cputable.h
index cbbfbec78b6b..d67fa9e26079 100644
--- a/include/asm-ppc64/cputable.h
+++ b/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
diff --git a/include/asm-ppc64/processor.h b/include/asm-ppc64/processor.h
index af28aa55d8c1..06aa07c2c71d 100644
--- a/include/asm-ppc64/processor.h
+++ b/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__ */