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Diffstat (limited to 'arch/x86/kernel/cpu/topology.c')
-rw-r--r--arch/x86/kernel/cpu/topology.c99
1 files changed, 99 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c
new file mode 100644
index 00000000000..4397e987a1c
--- /dev/null
+++ b/arch/x86/kernel/cpu/topology.c
@@ -0,0 +1,99 @@
+/*
+ * Check for extended topology enumeration cpuid leaf 0xb and if it
+ * exists, use it for populating initial_apicid and cpu topology
+ * detection.
+ */
+
+#include <linux/cpu.h>
+#include <asm/apic.h>
+#include <asm/pat.h>
+#include <asm/processor.h>
+
+/* leaf 0xb SMT level */
+#define SMT_LEVEL 0
+
+/* leaf 0xb sub-leaf types */
+#define INVALID_TYPE 0
+#define SMT_TYPE 1
+#define CORE_TYPE 2
+
+#define LEAFB_SUBTYPE(ecx) (((ecx) >> 8) & 0xff)
+#define BITS_SHIFT_NEXT_LEVEL(eax) ((eax) & 0x1f)
+#define LEVEL_MAX_SIBLINGS(ebx) ((ebx) & 0xffff)
+
+/*
+ * Check for extended topology enumeration cpuid leaf 0xb and if it
+ * exists, use it for populating initial_apicid and cpu topology
+ * detection.
+ */
+void __cpuinit detect_extended_topology(struct cpuinfo_x86 *c)
+{
+#ifdef CONFIG_SMP
+ unsigned int eax, ebx, ecx, edx, sub_index;
+ unsigned int ht_mask_width, core_plus_mask_width;
+ unsigned int core_select_mask, core_level_siblings;
+ static bool printed;
+
+ if (c->cpuid_level < 0xb)
+ return;
+
+ cpuid_count(0xb, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
+
+ /*
+ * check if the cpuid leaf 0xb is actually implemented.
+ */
+ if (ebx == 0 || (LEAFB_SUBTYPE(ecx) != SMT_TYPE))
+ return;
+
+ set_cpu_cap(c, X86_FEATURE_XTOPOLOGY);
+
+ /*
+ * initial apic id, which also represents 32-bit extended x2apic id.
+ */
+ c->initial_apicid = edx;
+
+ /*
+ * Populate HT related information from sub-leaf level 0.
+ */
+ core_level_siblings = smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx);
+ core_plus_mask_width = ht_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
+
+ sub_index = 1;
+ do {
+ cpuid_count(0xb, sub_index, &eax, &ebx, &ecx, &edx);
+
+ /*
+ * Check for the Core type in the implemented sub leaves.
+ */
+ if (LEAFB_SUBTYPE(ecx) == CORE_TYPE) {
+ core_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
+ core_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
+ break;
+ }
+
+ sub_index++;
+ } while (LEAFB_SUBTYPE(ecx) != INVALID_TYPE);
+
+ core_select_mask = (~(-1 << core_plus_mask_width)) >> ht_mask_width;
+
+ c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, ht_mask_width)
+ & core_select_mask;
+ c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, core_plus_mask_width);
+ /*
+ * Reinit the apicid, now that we have extended initial_apicid.
+ */
+ c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
+
+ c->x86_max_cores = (core_level_siblings / smp_num_siblings);
+
+ if (!printed) {
+ printk(KERN_INFO "CPU: Physical Processor ID: %d\n",
+ c->phys_proc_id);
+ if (c->x86_max_cores > 1)
+ printk(KERN_INFO "CPU: Processor Core ID: %d\n",
+ c->cpu_core_id);
+ printed = 1;
+ }
+ return;
+#endif
+}