[PATCH] x86_64: add support for Intel dual-core detection and displaying

Appended patch adds the support for Intel dual-core detection and displaying
the core related information in /proc/cpuinfo.  

It adds two new fields "core id" and "cpu cores" to x86 /proc/cpuinfo and the
"core id" field for x86_64("cpu cores" field is already present in x86_64).

Number of processor cores in a die is detected using cpuid(4) and this is
documented in IA-32 Intel Architecture Software Developer's Manual (vol 2a)
(http://developer.intel.com/design/pentium4/manuals/index_new.htm#sdm_vol2a)

This patch also adds cpu_core_map similar to cpu_sibling_map.

Slightly hacked by AK.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 22 insertions, 2 deletions

diff --git a/arch/x86_64/kernel/smpboot.c b/arch/x86_64/kernel/smpboot.c
index e5714090b00d..7e2de8925b0f 100644
--- a/arch/x86_64/kernel/smpboot.c
+++ b/arch/x86_64/kernel/smpboot.c
@@ -58,7 +58,10 @@
 int smp_num_siblings = 1;
 /* Package ID of each logical CPU */
 u8 phys_proc_id[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };
+/* Core ID of each logical CPU */
+u8 cpu_core_id[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };
 EXPORT_SYMBOL(phys_proc_id);
+EXPORT_SYMBOL(cpu_core_id);
 
 /* Bitmask of currently online CPUs */
 cpumask_t cpu_online_map;
@@ -71,6 +74,7 @@ static cpumask_t smp_commenced_mask;
 struct cpuinfo_x86 cpu_data[NR_CPUS] __cacheline_aligned;
 
 cpumask_t cpu_sibling_map[NR_CPUS] __cacheline_aligned;
+cpumask_t cpu_core_map[NR_CPUS] __cacheline_aligned;
 
 /*
  * Trampoline 80x86 program as an array.
@@ -713,6 +717,7 @@ static void __init smp_boot_cpus(unsigned int max_cpus)
                 io_apic_irqs = 0;
                 cpu_online_map = cpumask_of_cpu(0);
                 cpu_set(0, cpu_sibling_map[0]);
+                cpu_set(0, cpu_core_map[0]);
                 phys_cpu_present_map = physid_mask_of_physid(0);
                 if (APIC_init_uniprocessor())
                         printk(KERN_NOTICE "Local APIC not detected."
@@ -740,6 +745,7 @@ static void __init smp_boot_cpus(unsigned int max_cpus)
                 io_apic_irqs = 0;
                 cpu_online_map = cpumask_of_cpu(0);
                 cpu_set(0, cpu_sibling_map[0]);
+                cpu_set(0, cpu_core_map[0]);
                 phys_cpu_present_map = physid_mask_of_physid(0);
                 disable_apic = 1;
                 goto smp_done;
@@ -756,6 +762,7 @@ static void __init smp_boot_cpus(unsigned int max_cpus)
                 io_apic_irqs = 0;
                 cpu_online_map = cpumask_of_cpu(0);
                 cpu_set(0, cpu_sibling_map[0]);
+                cpu_set(0, cpu_core_map[0]);
                 phys_cpu_present_map = physid_mask_of_physid(0);
                 disable_apic = 1;
                 goto smp_done;
@@ -833,10 +840,13 @@ static void __init smp_boot_cpus(unsigned int max_cpus)
          * Construct cpu_sibling_map[], so that we can tell the
          * sibling CPU efficiently.
          */
-        for (cpu = 0; cpu < NR_CPUS; cpu++)
+        for (cpu = 0; cpu < NR_CPUS; cpu++) {
                 cpus_clear(cpu_sibling_map[cpu]);
+                cpus_clear(cpu_core_map[cpu]);
+        }
 
         for (cpu = 0; cpu < NR_CPUS; cpu++) {
+                struct cpuinfo_x86 *c = cpu_data + cpu;
                 int siblings = 0;
                 int i;
                 if (!cpu_isset(cpu, cpu_callout_map))
@@ -846,7 +856,7 @@ static void __init smp_boot_cpus(unsigned int max_cpus)
                         for (i = 0; i < NR_CPUS; i++) {
                                 if (!cpu_isset(i, cpu_callout_map))
                                         continue;
-                                if (phys_proc_id[cpu] == phys_proc_id[i]) {
+                                if (phys_proc_id[cpu] == cpu_core_id[i]) {
                                         siblings++;
                                         cpu_set(i, cpu_sibling_map[cpu]);
                                 }
@@ -862,6 +872,16 @@ static void __init smp_boot_cpus(unsigned int max_cpus)
                                siblings, cpu, smp_num_siblings);
                         smp_num_siblings = siblings;
                 }       
+                if (c->x86_num_cores > 1) {
+                        for (i = 0; i < NR_CPUS; i++) {
+                                if (!cpu_isset(i, cpu_callout_map))
+                                        continue;
+                                if (phys_proc_id[cpu] == phys_proc_id[i]) {
+                                        cpu_set(i, cpu_core_map[cpu]);
+                                }
+                        }
+                } else
+                        cpu_core_map[cpu] = cpu_sibling_map[cpu];
         }
 
         Dprintk("Boot done.\n");