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
+}