[SPARC64]: Add SMT scheduling support for Niagara.

The mapping is a simple "(cpuid >> 2) == core" for now.
Later we'll add more sophisticated code that will walk
the sun4v machine description and figure this out from
there.

We should also add core mappings for jaguar and panther
processors.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 0 deletions

diff --git a/arch/sparc64/kernel/smp.c b/arch/sparc64/kernel/smp.c
index cf56128097c8..373a701c90a5 100644
--- a/arch/sparc64/kernel/smp.c
+++ b/arch/sparc64/kernel/smp.c
@@ -47,6 +47,8 @@ static unsigned char boot_cpu_id;
 
 cpumask_t cpu_online_map __read_mostly = CPU_MASK_NONE;
 cpumask_t phys_cpu_present_map __read_mostly = CPU_MASK_NONE;
+cpumask_t cpu_sibling_map[NR_CPUS] __read_mostly =
+	{ [0 ... NR_CPUS-1] = CPU_MASK_NONE };
 static cpumask_t smp_commenced_mask;
 static cpumask_t cpu_callout_map;
 
@@ -1291,6 +1293,8 @@ int setup_profiling_timer(unsigned int multiplier)
 /* Constrain the number of cpus to max_cpus.  */
 void __init smp_prepare_cpus(unsigned int max_cpus)
 {
+	int i;
+
 	if (num_possible_cpus() > max_cpus) {
 		int instance, mid;
 
@@ -1305,6 +1309,20 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 		}
 	}
 
+	for_each_cpu(i) {
+		if (tlb_type == hypervisor) {
+			int j;
+
+			/* XXX get this mapping from machine description */
+			for_each_cpu(j) {
+				if ((j >> 2) == (i >> 2))
+					cpu_set(j, cpu_sibling_map[i]);
+			}
+		} else {
+			cpu_set(i, cpu_sibling_map[i]);
+		}
+	}
+
 	smp_store_cpu_info(boot_cpu_id);
 }