x86, amd: Extract compute unit information for AMD CPUs

Get compute unit information from CPUID Fn8000_001E_EBX.
(See AMD CPUID Specification - publication # 25481, revision 2.34,
September 2010.)

Note that each core on a compute unit still has a core_id of its own.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
LKML-Reference: <20100930123857.GE20545@loge.amd.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 15 insertions, 5 deletions

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 7e6a37d24253..70168ab88b7f 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -256,21 +256,29 @@ static int __cpuinit nearby_node(int apicid)
  * Fixup core topology information for
  * (1) AMD multi-node processors
  *     Assumption: Number of cores in each internal node is the same.
+ * (2) AMD processors supporting compute units
  */
 #ifdef CONFIG_X86_HT
 static void __cpuinit amd_get_topology(struct cpuinfo_x86 *c)
 {
-        u32 nodes, cores_per_node;
+        u32 nodes;
         u8 node_id;
-        unsigned long long value;
         int cpu = smp_processor_id();
 
         /* get information required for multi-node processors */
         if (cpu_has(c, X86_FEATURE_TOPOEXT)) {
-                value = cpuid_ecx(0x8000001e);
-                nodes = ((value >> 8) & 7) + 1;
-                node_id = value & 7;
+                u32 eax, ebx, ecx, edx;
+
+                cpuid(0x8000001e, &eax, &ebx, &ecx, &edx);
+                nodes = ((ecx >> 8) & 7) + 1;
+                node_id = ecx & 7;
+
+                /* get compute unit information */
+                smp_num_siblings = ((ebx >> 8) & 3) + 1;
+                c->compute_unit_id = ebx & 0xff;
         } else if (cpu_has(c, X86_FEATURE_NODEID_MSR)) {
+                u64 value;
+
                 rdmsrl(MSR_FAM10H_NODE_ID, value);
                 nodes = ((value >> 3) & 7) + 1;
                 node_id = value & 7;
@@ -279,6 +287,8 @@ static void __cpuinit amd_get_topology(struct cpuinfo_x86 *c)
 
         /* fixup multi-node processor information */
         if (nodes > 1) {
+                u32 cores_per_node;
+
                 set_cpu_cap(c, X86_FEATURE_AMD_DCM);
                 cores_per_node = c->x86_max_cores / nodes;