[PATCH 3/8] x86: Add cpu_node topology detection for AMD Magny-Cours

Andreas Herrmann
2009-08-07T13:00:32Z

This adapts CPU topology detection for AMD Magny-Cours.

Here is example output from two cores on same package but different
internal cpu_nodes:

/sys/devices/system/cpu/cpu5:
physical_package_id : 0
core_id : 5
thread_siblings : 00000020
thread_siblings_list : 5
cpu_node_id : 0
cpu_node_siblings : 0000003f
cpu_node_siblings_list : 0-5
core_siblings : 00000fff
core_siblings_list : 0-11
/sys/devices/system/cpu/cpu6:
physical_package_id : 0
core_id : 0
thread_siblings : 00000040
thread_siblings_list : 6
cpu_node_id : 1
cpu_node_siblings : 00000fc0
cpu_node_siblings_list : 6-11
core_siblings : 00000fff
core_siblings_list : 0-11

Included allnoconfig compile fix by Nicolas Palix <npalix@diku.dk>.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
---
arch/x86/include/asm/cpufeature.h | 1 +
arch/x86/kernel/cpu/amd.c | 69 +++++++++++++++++++++++++++++++++++-
2 files changed, 68 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 4a28d22..847fee6 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -95,6 +95,7 @@
#define X86_FEATURE_NONSTOP_TSC (3*32+24) /* TSC does not stop in C states */
#define X86_FEATURE_CLFLUSH_MONITOR (3*32+25) /* "" clflush reqd with monitor */
#define X86_FEATURE_EXTD_APICID (3*32+26) /* has extended APICID (8 bits) */
+#define X86_FEATURE_AMD_DCM (3*32+27) /* multi-node processor */

/* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */
#define X86_FEATURE_XMM3 (4*32+ 0) /* "pni" SSE-3 */
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index ec6c7a8..f18ece1 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -253,6 +253,60 @@ static int __cpuinit nearby_node(int apicid)
#endif

/*
+ * 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.
+ */
+#ifdef CONFIG_X86_HT
+static void __cpuinit amd_fixup_dcm(struct cpuinfo_x86 *c)
+{
+#ifdef CONFIG_PCI
+ u32 t, cpn;
+ u8 n;
+
+ /* 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)))
+ return;
+
+ set_cpu_cap(c, X86_FEATURE_AMD_DCM);
+
+ /* cores per node: each internal node has half the number of cores */
+ cpn = c->x86_max_cores >> 1;
+
+ /* 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)
+ c->cpu_node_id = 0;
+ else
+ c->cpu_node_id = 1;
+ } else {
+ if (c->cpu_core_id < cpn)
+ c->cpu_node_id = 1;
+ else
+ c->cpu_node_id = 0;
+ }
+
+ /* fixup core id to be in range from 0 to cpn */
+ c->cpu_core_id = c->cpu_core_id % cpn;
+#endif
+}
+#endif
+
+/*
* On a AMD dual core setup the lower bits of the APIC id distingush the cores.
* Assumes number of cores is a power of two.
*/
@@ -267,8 +321,15 @@ static void __cpuinit amd_detect_cmp(struct cpuinfo_x86 *c)
c->cpu_core_id = c->initial_apicid & ((1 << bits)-1);
/* Convert the initial APIC ID into the socket ID */
c->phys_proc_id = c->initial_apicid >> bits;
+ /* fixup topology information on multi-node processors */
+ if ((c->x86 == 0x10) && (c->x86_model == 9))
+ amd_fixup_dcm(c);
/* use socket ID also for last level cache */
- per_cpu(cpu_llc_id, cpu) = c->phys_proc_id;
+ if (cpu_has(c, X86_FEATURE_AMD_DCM))
+ per_cpu(cpu_llc_id, cpu) = (c->phys_proc_id << 1) +
+ c->cpu_node_id;
+ else
+ per_cpu(cpu_llc_id, cpu) = c->phys_proc_id;
#endif
}

@@ -279,7 +340,11 @@ static void __cpuinit srat_detect_node(struct cpuinfo_x86 *c)
int node;
unsigned apicid = cpu_has_apic ? hard_smp_processor_id() : c->apicid;

- node = c->phys_proc_id;
+ if (cpu_has(c, X86_FEATURE_AMD_DCM))
+ node = (c->phys_proc_id << 1) + c->cpu_node_id;
+ else
+ node = c->phys_proc_id;
+
if (apicid_to_node[apicid] != NUMA_NO_NODE)
node = apicid_to_node[apicid];
if (!node_online(node)) {
--
1.6.3.3