[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>

4 files changed, 58 insertions, 14 deletions

diff --git a/arch/i386/kernel/cpu/amd.c b/arch/i386/kernel/cpu/amd.c
index ae94585..fa10d0a 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 ebd5d82..ed4c9c3 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 b8d847b..121aa21 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 89a2956..0f1125b 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;
 }