We would like to be able to provide a mechanism for finding the NBC for
each node in multi-node platforms. For this, we will need the number of
nodes per processor.

So, factor this calculation out of amd_get_topology() and provide separate
getter function 'amd_get_nbc_for_node' for obtaining NBC for a node.

Another useful calculation is to find the NBC of a node on which a given cpu
is on. Provide a getter for this as well.
 - We are using it in EDAC drivers, MCE handlers right away, so marked
  extern.
 - We currently don't use amd_get_nbc_for_node outside of here, so
  marking it static.  We can make this extern as and when need arises.

While at it, reverse the return condition in amd_get_topology
and save an indent level.

Signed-off-by: Aravind Gopalakrishnan <aravind.gopalakrish...@amd.com>
---
 arch/x86/include/asm/processor.h |  1 +
 arch/x86/kernel/cpu/amd.c        | 78 ++++++++++++++++++++++++++++++++--------
 2 files changed, 65 insertions(+), 14 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index a092a0c..6e1dc06 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -979,6 +979,7 @@ static inline int mpx_disable_management(struct task_struct 
*tsk)
 #endif /* CONFIG_X86_INTEL_MPX */
 
 extern u16 amd_get_nb_id(int cpu);
+extern unsigned int amd_get_nbc_for_cpu(int cpu);
 
 static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves)
 {
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index a220239..0c0eae5 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -281,6 +281,28 @@ static int nearby_node(int apicid)
 }
 #endif
 
+#ifdef CONFIG_X86_HT
+static u32 amd_get_num_nodes(struct cpuinfo_x86 *c)
+{
+       u32 nodes = 1;
+
+       if (cpu_has_topoext) {
+               u32 ecx;
+
+               ecx = cpuid_ecx(0x8000001e);
+               nodes = ((ecx >> 8) & 7) + 1;
+       } else if (cpu_has(c, X86_FEATURE_NODEID_MSR)) {
+               u64 value;
+
+               rdmsrl(MSR_FAM10H_NODE_ID, value);
+               nodes = ((value >> 3) & 7) + 1;
+       }
+
+       return nodes;
+}
+EXPORT_SYMBOL_GPL(amd_get_num_nodes);
+#endif
+
 /*
  * Fixup core topology information for
  * (1) AMD multi-node processors
@@ -291,15 +313,18 @@ static int nearby_node(int apicid)
 static void amd_get_topology(struct cpuinfo_x86 *c)
 {
        u32 nodes, cores_per_cu = 1;
+       u32 cores_per_node;
+       u32 cus_per_node;
        u8 node_id;
        int cpu = smp_processor_id();
 
        /* get information required for multi-node processors */
+       nodes = amd_get_num_nodes(c);
+
        if (cpu_has_topoext) {
                u32 eax, ebx, ecx, edx;
 
                cpuid(0x8000001e, &eax, &ebx, &ecx, &edx);
-               nodes = ((ecx >> 8) & 7) + 1;
                node_id = ecx & 7;
 
                /* get compute unit information */
@@ -310,27 +335,24 @@ static void amd_get_topology(struct cpuinfo_x86 *c)
                u64 value;
 
                rdmsrl(MSR_FAM10H_NODE_ID, value);
-               nodes = ((value >> 3) & 7) + 1;
                node_id = value & 7;
        } else
                return;
 
        /* fixup multi-node processor information */
-       if (nodes > 1) {
-               u32 cores_per_node;
-               u32 cus_per_node;
+       if (nodes < 2)
+               return;
 
-               set_cpu_cap(c, X86_FEATURE_AMD_DCM);
-               cores_per_node = c->x86_max_cores / nodes;
-               cus_per_node = cores_per_node / cores_per_cu;
+       set_cpu_cap(c, X86_FEATURE_AMD_DCM);
+       cores_per_node = c->x86_max_cores / nodes;
+       cus_per_node = cores_per_node / cores_per_cu;
 
-               /* store NodeID, use llc_shared_map to store sibling info */
-               per_cpu(cpu_llc_id, cpu) = node_id;
+       /* store NodeID, use llc_shared_map to store sibling info */
+       per_cpu(cpu_llc_id, cpu) = node_id;
 
-               /* core id has to be in the [0 .. cores_per_node - 1] range */
-               c->cpu_core_id %= cores_per_node;
-               c->compute_unit_id %= cus_per_node;
-       }
+       /* core id has to be in the [0 .. cores_per_node - 1] range */
+       c->cpu_core_id %= cores_per_node;
+       c->compute_unit_id %= cus_per_node;
 }
 #endif
 
@@ -365,6 +387,34 @@ u16 amd_get_nb_id(int cpu)
 }
 EXPORT_SYMBOL_GPL(amd_get_nb_id);
 
+#ifdef CONFIG_X86_HT
+static u32 amd_get_nbc_for_node(int node_id)
+{
+       struct cpuinfo_x86 *c = &boot_cpu_data;
+       u32 nodes, cores_per_node;
+
+       nodes = amd_get_num_nodes(c);
+       cores_per_node = c->x86_max_cores / nodes;
+
+       return cores_per_node * node_id;
+}
+EXPORT_SYMBOL_GPL(amd_get_nbc_for_node);
+#endif
+
+#ifdef CONFIG_X86_HT
+unsigned int amd_get_nbc_for_cpu(int cpu)
+{
+       unsigned int nbc = 0;
+
+       /* for multi-node */
+       if (test_cpu_cap(&boot_cpu_data, X86_FEATURE_AMD_DCM))
+               nbc = amd_get_nbc_for_node(amd_get_nb_id(cpu));
+
+       return nbc;
+}
+EXPORT_SYMBOL_GPL(amd_get_nbc_for_cpu);
+#endif
+
 static void srat_detect_node(struct cpuinfo_x86 *c)
 {
 #ifdef CONFIG_NUMA
-- 
2.0.2

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