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>

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 325b7bd..69e80c2 100644 (file)
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -110,6 +110,8 @@ struct cpuinfo_x86 {
        u16                     phys_proc_id;
        /* Core id: */
        u16                     cpu_core_id;
+       /* Compute unit id */
+       u8                      compute_unit_id;
        /* Index into per_cpu list: */
        u16                     cpu_index;
 #endif

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 7e6a37d..70168ab 100644 (file)
--- 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;