[PATCH] ppc64: set/clear SMT capable bit at boot

Allow the SMT bit to be set/reset at boot, like the ALTIVEC bit.  This
means we will enable SMT on unknown cpus that support 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>

1 files changed, 12 insertions, 0 deletions

diff --git a/arch/ppc64/kernel/prom.c b/arch/ppc64/kernel/prom.c
index eb6538b58008..47727a6f7346 100644
--- a/arch/ppc64/kernel/prom.c
+++ b/arch/ppc64/kernel/prom.c
@@ -884,6 +884,7 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
 {
         char *type = get_flat_dt_prop(node, "device_type", NULL);
         u32 *prop;
+        unsigned long size;
 
         /* We are scanning "cpu" nodes only */
         if (type == NULL || strcmp(type, "cpu") != 0)
@@ -929,6 +930,17 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
                 cur_cpu_spec->cpu_user_features |= PPC_FEATURE_HAS_ALTIVEC;
         }
 
+        /*
+         * Check for an SMT capable CPU and set the CPU feature. We do
+         * this by looking at the size of the ibm,ppc-interrupt-server#s
+         * property
+         */
+        prop = (u32 *)get_flat_dt_prop(node, "ibm,ppc-interrupt-server#s",
+                                       &size);
+        cur_cpu_spec->cpu_features &= ~CPU_FTR_SMT;
+        if (prop && ((size / sizeof(u32)) > 1))
+                cur_cpu_spec->cpu_features |= CPU_FTR_SMT;
+
         return 0;
 }