[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, 20 insertions, 8 deletions

diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c
index ebd5d8247faa..ed4c9c3fe667 100644
--- a/arch/i386/kernel/cpu/common.c
+++ b/arch/i386/kernel/cpu/common.c
@@ -434,7 +434,7 @@ void __init identify_cpu(struct cpuinfo_x86 *c)
 void __init detect_ht(struct cpuinfo_x86 *c)
 {
         u32     eax, ebx, ecx, edx;
-        int     index_lsb, index_msb, tmp;
+        int     index_msb, tmp;
         int     cpu = smp_processor_id();
 
         if (!cpu_has(c, X86_FEATURE_HT))
@@ -446,7 +446,6 @@ void __init detect_ht(struct cpuinfo_x86 *c)
         if (smp_num_siblings == 1) {
                 printk(KERN_INFO  "CPU: Hyper-Threading is disabled\n");
         } else if (smp_num_siblings > 1 ) {
-                index_lsb = 0;
                 index_msb = 31;
 
                 if (smp_num_siblings > NR_CPUS) {
@@ -455,21 +454,34 @@ void __init detect_ht(struct cpuinfo_x86 *c)
                         return;
                 }
                 tmp = smp_num_siblings;
-                while ((tmp & 1) == 0) {
-                        tmp >>=1 ;
-                        index_lsb++;
-                }
-                tmp = smp_num_siblings;
                 while ((tmp & 0x80000000 ) == 0) {
                         tmp <<=1 ;
                         index_msb--;
                 }
-                if (index_lsb != index_msb )
+                if (smp_num_siblings & (smp_num_siblings - 1))
                         index_msb++;
                 phys_proc_id[cpu] = phys_pkg_id((ebx >> 24) & 0xFF, index_msb);
 
                 printk(KERN_INFO  "CPU: Physical Processor ID: %d\n",
                        phys_proc_id[cpu]);
+
+                smp_num_siblings = smp_num_siblings / c->x86_num_cores;
+
+                tmp = smp_num_siblings;
+                index_msb = 31;
+                while ((tmp & 0x80000000) == 0) {
+                        tmp <<=1 ;
+                        index_msb--;
+                }
+
+                if (smp_num_siblings & (smp_num_siblings - 1))
+                        index_msb++;
+
+                cpu_core_id[cpu] = phys_pkg_id((ebx >> 24) & 0xFF, index_msb);
+
+                if (c->x86_num_cores > 1)
+                        printk(KERN_INFO  "CPU: Processor Core ID: %d\n",
+                               cpu_core_id[cpu]);
         }
 }
 #endif