[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, 29 insertions, 2 deletions

diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c
index 332ee7a1d1a1..fd36d2f65f88 100644
--- a/arch/i386/kernel/smpboot.c
+++ b/arch/i386/kernel/smpboot.c
@@ -62,6 +62,8 @@ static int __initdata smp_b_stepping;
 int smp_num_siblings = 1;
 int phys_proc_id[NR_CPUS]; /* Package ID of each logical CPU */
 EXPORT_SYMBOL(phys_proc_id);
+int cpu_core_id[NR_CPUS]; /* Core ID of each logical CPU */
+EXPORT_SYMBOL(cpu_core_id);
 
 /* bitmap of online cpus */
 cpumask_t cpu_online_map;
@@ -885,6 +887,7 @@ static int boot_cpu_logical_apicid;
 void *xquad_portio;
 
 cpumask_t cpu_sibling_map[NR_CPUS] __cacheline_aligned;
+cpumask_t cpu_core_map[NR_CPUS] __cacheline_aligned;
 
 static void __init smp_boot_cpus(unsigned int max_cpus)
 {
@@ -907,6 +910,9 @@ static void __init smp_boot_cpus(unsigned int max_cpus)
         cpus_clear(cpu_sibling_map[0]);
         cpu_set(0, cpu_sibling_map[0]);
 
+        cpus_clear(cpu_core_map[0]);
+        cpu_set(0, cpu_core_map[0]);
+
         /*
          * If we couldn't find an SMP configuration at boot time,
          * get out of here now!
@@ -919,6 +925,8 @@ static void __init smp_boot_cpus(unsigned int max_cpus)
                         printk(KERN_NOTICE "Local APIC not detected."
                                            " Using dummy APIC emulation.\n");
                 map_cpu_to_logical_apicid();
+                cpu_set(0, cpu_sibling_map[0]);
+                cpu_set(0, cpu_core_map[0]);
                 return;
         }
 
@@ -942,6 +950,8 @@ static void __init smp_boot_cpus(unsigned int max_cpus)
                 printk(KERN_ERR "... forcing use of dummy APIC emulation. (tell your hw vendor)\n");
                 smpboot_clear_io_apic_irqs();
                 phys_cpu_present_map = physid_mask_of_physid(0);
+                cpu_set(0, cpu_sibling_map[0]);
+                cpu_set(0, cpu_core_map[0]);
                 return;
         }
 
@@ -955,6 +965,8 @@ static void __init smp_boot_cpus(unsigned int max_cpus)
                 printk(KERN_INFO "SMP mode deactivated, forcing use of dummy APIC emulation.\n");
                 smpboot_clear_io_apic_irqs();
                 phys_cpu_present_map = physid_mask_of_physid(0);
+                cpu_set(0, cpu_sibling_map[0]);
+                cpu_set(0, cpu_core_map[0]);
                 return;
         }
 
@@ -1035,10 +1047,13 @@ static void __init smp_boot_cpus(unsigned int max_cpus)
          * construct cpu_sibling_map[], so that we can tell sibling CPUs
          * 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))
@@ -1048,7 +1063,7 @@ 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 (cpu_core_id[cpu] == cpu_core_id[i]) {
                                         siblings++;
                                         cpu_set(i, cpu_sibling_map[cpu]);
                                 }
@@ -1060,6 +1075,18 @@ static void __init smp_boot_cpus(unsigned int max_cpus)
 
                 if (siblings != smp_num_siblings)
                         printk(KERN_WARNING "WARNING: %d siblings found for CPU%d, should be %d\n", siblings, cpu, smp_num_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];
+                }
         }
 
         if (nmi_watchdog == NMI_LOCAL_APIC)