[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>

5 files changed, 87 insertions, 16 deletions

diff --git a/arch/i386/kernel/cpu/amd.c b/arch/i386/kernel/cpu/amd.c
index ae94585d0445..fa10d0a509c7 100644
--- a/arch/i386/kernel/cpu/amd.c
+++ b/arch/i386/kernel/cpu/amd.c
@@ -188,6 +188,13 @@ static void __init init_amd(struct cpuinfo_x86 *c)
         }
 
         display_cacheinfo(c);
+
+        if (cpuid_eax(0x80000000) >= 0x80000008) {
+                c->x86_num_cores = (cpuid_ecx(0x80000008) & 0xff) + 1;
+                if (c->x86_num_cores & (c->x86_num_cores - 1))
+                        c->x86_num_cores = 1;
+        }
+
         detect_ht(c);
 
 #ifdef CONFIG_X86_HT
@@ -199,12 +206,6 @@ static void __init init_amd(struct cpuinfo_x86 *c)
         if (cpu_has(c, X86_FEATURE_CMP_LEGACY))
                 smp_num_siblings = 1;
 #endif
-
-        if (cpuid_eax(0x80000000) >= 0x80000008) {
-                c->x86_num_cores = (cpuid_ecx(0x80000008) & 0xff) + 1;
-                if (c->x86_num_cores & (c->x86_num_cores - 1))
-                        c->x86_num_cores = 1;
-        }
 }
 
 static unsigned int amd_size_cache(struct cpuinfo_x86 * c, unsigned int size)
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
diff --git a/arch/i386/kernel/cpu/intel.c b/arch/i386/kernel/cpu/intel.c
index b8d847b850dc..121aa2176e69 100644
--- a/arch/i386/kernel/cpu/intel.c
+++ b/arch/i386/kernel/cpu/intel.c
@@ -77,6 +77,27 @@ static void __init Intel_errata_workarounds(struct cpuinfo_x86 *c)
 }
 
 
+/*
+ * find out the number of processor cores on the die
+ */
+static int __init num_cpu_cores(struct cpuinfo_x86 *c)
+{
+        unsigned int eax;
+
+        if (c->cpuid_level < 4)
+                return 1;
+
+        __asm__("cpuid"
+                : "=a" (eax)
+                : "0" (4), "c" (0)
+                : "bx", "dx");
+
+        if (eax & 0x1f)
+                return ((eax >> 26) + 1);
+        else
+                return 1;
+}
+
 static void __init init_intel(struct cpuinfo_x86 *c)
 {
         unsigned int l2 = 0;
@@ -139,6 +160,8 @@ static void __init init_intel(struct cpuinfo_x86 *c)
         if ( p )
                 strcpy(c->x86_model_id, p);
         
+        c->x86_num_cores = num_cpu_cores(c);
+
         detect_ht(c);
 
         /* Work around errata */
diff --git a/arch/i386/kernel/cpu/proc.c b/arch/i386/kernel/cpu/proc.c
index 89a2956ee657..0f1125b15b76 100644
--- a/arch/i386/kernel/cpu/proc.c
+++ b/arch/i386/kernel/cpu/proc.c
@@ -129,6 +129,14 @@ static int show_cpuinfo(struct seq_file *m, void *v)
         seq_printf(m, "\nbogomips\t: %lu.%02lu\n\n",
                      c->loops_per_jiffy/(500000/HZ),
                      (c->loops_per_jiffy/(5000/HZ)) % 100);
+
+#ifdef CONFIG_SMP
+        /* Put new fields at the end to lower the probability of
+           breaking user space parsers. */
+        seq_printf(m, "core id\t\t: %d\n", cpu_core_id[n]);
+        seq_printf(m, "cpu cores\t: %d\n", c->x86_num_cores);
+#endif
+
         return 0;
 }
 
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)