[PATCH 1/3] x86,amd: Refactor amd cpu topology functions for multi-node processors

[Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>]

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.Gopalakrishnan@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