x86, amd: Get multi-node CPU info from NodeId MSR instead of PCI config space

Use NodeId MSR to get NodeId and number of nodes per processor.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
LKML-Reference: <20091216144355.GB28798@alberich.amd.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 15 insertions, 38 deletions

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 8dc3ea145c97..e485825130d2 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -254,59 +254,36 @@ static int __cpuinit nearby_node(int apicid)
 
 /*
  * Fixup core topology information for AMD multi-node processors.
- * Assumption 1: Number of cores in each internal node is the same.
- * Assumption 2: Mixed systems with both single-node and dual-node
- *               processors are not supported.
+ * Assumption: Number of cores in each internal node is the same.
  */
 #ifdef CONFIG_X86_HT
 static void __cpuinit amd_fixup_dcm(struct cpuinfo_x86 *c)
 {
-#ifdef CONFIG_PCI
-        u32 t, cpn;
-        u8 n, n_id;
+        unsigned long long value;
+        u32 nodes, cores_per_node;
         int cpu = smp_processor_id();
 
+        if (!cpu_has(c, X86_FEATURE_NODEID_MSR))
+                return;
+
         /* fixup topology information only once for a core */
         if (cpu_has(c, X86_FEATURE_AMD_DCM))
                 return;
 
-        /* check for multi-node processor on boot cpu */
-        t = read_pci_config(0, 24, 3, 0xe8);
-        if (!(t & (1 << 29)))
+        rdmsrl(MSR_FAM10H_NODE_ID, value);
+
+        nodes = ((value >> 3) & 7) + 1;
+        if (nodes == 1)
                 return;
 
         set_cpu_cap(c, X86_FEATURE_AMD_DCM);
+        cores_per_node = c->x86_max_cores / nodes;
 
-        /* cores per node: each internal node has half the number of cores */
-        cpn = c->x86_max_cores >> 1;
+        /* store NodeID, use llc_shared_map to store sibling info */
+        per_cpu(cpu_llc_id, cpu) = value & 7;
 
-        /* even-numbered NB_id of this dual-node processor */
-        n = c->phys_proc_id << 1;
-
-        /*
-         * determine internal node id and assign cores fifty-fifty to
-         * each node of the dual-node processor
-         */
-        t = read_pci_config(0, 24 + n, 3, 0xe8);
-        n = (t>>30) & 0x3;
-        if (n == 0) {
-                if (c->cpu_core_id < cpn)
-                        n_id = 0;
-                else
-                        n_id = 1;
-        } else {
-                if (c->cpu_core_id < cpn)
-                        n_id = 1;
-                else
-                        n_id = 0;
-        }
-
-        /* compute entire NodeID, use llc_shared_map to store sibling info */
-        per_cpu(cpu_llc_id, cpu) = (c->phys_proc_id << 1) + n_id;
-
-        /* fixup core id to be in range from 0 to cpn */
-        c->cpu_core_id = c->cpu_core_id % cpn;
-#endif
+        /* fixup core id to be in range from 0 to (cores_per_node - 1) */
+        c->cpu_core_id = c->cpu_core_id % cores_per_node;
 }
 #endif