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


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