x86/hwmon: fix initialization of coretemp

Using cpuid_eax() to determine feature availability on other than
the current CPU is invalid. And feature availability should also be
checked in the hotplug code path.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Rudolf Marek <r.marek@assembler.cz>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>

arch/x86/include/asm/cpufeature.h

@@ -168,6 +168,7 @@
 #define X86_FEATURE_XSAVEOPT	(7*32+ 4) /* Optimized Xsave */
 #define X86_FEATURE_PLN		(7*32+ 5) /* Intel Power Limit Notification */
 #define X86_FEATURE_PTS		(7*32+ 6) /* Intel Package Thermal Status */
+#define X86_FEATURE_DTS		(7*32+ 7) /* Digital Thermal Sensor */
 
 /* Virtualization flags: Linux defined, word 8 */
 #define X86_FEATURE_TPR_SHADOW  (8*32+ 0) /* Intel TPR Shadow */

arch/x86/kernel/cpu/scattered.c

@@ -31,6 +31,7 @@ void __cpuinit init_scattered_cpuid_features(struct cpuinfo_x86 *c)
 	const struct cpuid_bit *cb;
 
 	static const struct cpuid_bit __cpuinitconst cpuid_bits[] = {
+		{ X86_FEATURE_DTS,		CR_EAX, 0, 0x00000006, 0 },
 		{ X86_FEATURE_IDA,		CR_EAX, 1, 0x00000006, 0 },
 		{ X86_FEATURE_ARAT,		CR_EAX, 2, 0x00000006, 0 },
 		{ X86_FEATURE_PLN,		CR_EAX, 4, 0x00000006, 0 },

drivers/hwmon/coretemp.c

@@ -423,9 +423,18 @@ static int __cpuinit coretemp_device_add(unsigned int cpu)
 	int err;
 	struct platform_device *pdev;
 	struct pdev_entry *pdev_entry;
-#ifdef CONFIG_SMP
 	struct cpuinfo_x86 *c = &cpu_data(cpu);
-#endif
+
+	/*
+	 * CPUID.06H.EAX[0] indicates whether the CPU has thermal
+	 * sensors. We check this bit only, all the early CPUs
+	 * without thermal sensors will be filtered out.
+	 */
+	if (!cpu_has(c, X86_FEATURE_DTS)) {
+		printk(KERN_INFO DRVNAME ": CPU (model=0x%x)"
+		       " has no thermal sensor.\n", c->x86_model);
+		return 0;
+	}
 
 	mutex_lock(&pdev_list_mutex);
 
@@ -527,20 +536,8 @@ static int __init coretemp_init(void)
 	if (err)
 		goto exit;
 
-	for_each_online_cpu(i) {
-		struct cpuinfo_x86 *c = &cpu_data(i);
-		/*
-		 * CPUID.06H.EAX[0] indicates whether the CPU has thermal
-		 * sensors. We check this bit only, all the early CPUs
-		 * without thermal sensors will be filtered out.
-		 */
-		if (c->cpuid_level >= 6 && (cpuid_eax(0x06) & 0x01))
-			coretemp_device_add(i);
-		else {
-			printk(KERN_INFO DRVNAME ": CPU (model=0x%x)"
-				" has no thermal sensor.\n", c->x86_model);
-		}
-	}
+	for_each_online_cpu(i)
+		coretemp_device_add(i);
 
 #ifndef CONFIG_HOTPLUG_CPU
 	if (list_empty(&pdev_list)) {