x86: move prefill_possible_map to common file

this patches moves prefill_possible_map() to smpboot.c
Right now it is x86_64-specific, but nothing intrinsically
prevents it to be used by i386

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/Makefile

@@ -46,7 +46,7 @@ obj-$(CONFIG_MICROCODE)		+= microcode.o
 obj-$(CONFIG_PCI)		+= early-quirks.o
 apm-y				:= apm_32.o
 obj-$(CONFIG_APM)		+= apm.o
-obj-$(CONFIG_X86_SMP)		+= smp_$(BITS).o smpboot_$(BITS).o tsc_sync.o
+obj-$(CONFIG_X86_SMP)		+= smp_$(BITS).o smpboot_$(BITS).o smpboot.o tsc_sync.o
 obj-$(CONFIG_X86_32_SMP)	+= smpcommon_32.o
 obj-$(CONFIG_X86_64_SMP)	+= smp_64.o smpboot_64.o tsc_sync.o
 obj-$(CONFIG_X86_TRAMPOLINE)	+= trampoline_$(BITS).o

arch/x86/kernel/smpboot.c

@@ -0,0 +1,53 @@
+#include <linux/init.h>
+#include <linux/smp.h>
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+int additional_cpus __initdata = -1;
+
+static __init int setup_additional_cpus(char *s)
+{
+	return s && get_option(&s, &additional_cpus) ? 0 : -EINVAL;
+}
+early_param("additional_cpus", setup_additional_cpus);
+
+/*
+ * cpu_possible_map should be static, it cannot change as cpu's
+ * are onlined, or offlined. The reason is per-cpu data-structures
+ * are allocated by some modules at init time, and dont expect to
+ * do this dynamically on cpu arrival/departure.
+ * cpu_present_map on the other hand can change dynamically.
+ * In case when cpu_hotplug is not compiled, then we resort to current
+ * behaviour, which is cpu_possible == cpu_present.
+ * - Ashok Raj
+ *
+ * Three ways to find out the number of additional hotplug CPUs:
+ * - If the BIOS specified disabled CPUs in ACPI/mptables use that.
+ * - The user can overwrite it with additional_cpus=NUM
+ * - Otherwise don't reserve additional CPUs.
+ * We do this because additional CPUs waste a lot of memory.
+ * -AK
+ */
+__init void prefill_possible_map(void)
+{
+	int i;
+	int possible;
+
+	if (additional_cpus == -1) {
+		if (disabled_cpus > 0)
+			additional_cpus = disabled_cpus;
+		else
+			additional_cpus = 0;
+	}
+	possible = num_processors + additional_cpus;
+	if (possible > NR_CPUS)
+		possible = NR_CPUS;
+
+	printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n",
+		possible, max_t(int, possible - num_processors, 0));
+
+	for (i = 0; i < possible; i++)
+		cpu_set(i, cpu_possible_map);
+}
+#endif
+

arch/x86/kernel/smpboot_64.c

@@ -749,51 +749,6 @@ static __init void disable_smp(void)
 	cpu_set(0, per_cpu(cpu_core_map, 0));
 }
 
-#ifdef CONFIG_HOTPLUG_CPU
-
-int additional_cpus __initdata = -1;
-
-/*
- * cpu_possible_map should be static, it cannot change as cpu's
- * are onlined, or offlined. The reason is per-cpu data-structures
- * are allocated by some modules at init time, and dont expect to
- * do this dynamically on cpu arrival/departure.
- * cpu_present_map on the other hand can change dynamically.
- * In case when cpu_hotplug is not compiled, then we resort to current
- * behaviour, which is cpu_possible == cpu_present.
- * - Ashok Raj
- *
- * Three ways to find out the number of additional hotplug CPUs:
- * - If the BIOS specified disabled CPUs in ACPI/mptables use that.
- * - The user can overwrite it with additional_cpus=NUM
- * - Otherwise don't reserve additional CPUs.
- * We do this because additional CPUs waste a lot of memory.
- * -AK
- */
-__init void prefill_possible_map(void)
-{
-	int i;
-	int possible;
-
- 	if (additional_cpus == -1) {
- 		if (disabled_cpus > 0)
- 			additional_cpus = disabled_cpus;
- 		else
-			additional_cpus = 0;
- 	}
-	possible = num_processors + additional_cpus;
-	if (possible > NR_CPUS) 
-		possible = NR_CPUS;
-
-	printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n",
-		possible,
-	        max_t(int, possible - num_processors, 0));
-
-	for (i = 0; i < possible; i++)
-		cpu_set(i, cpu_possible_map);
-}
-#endif
-
 /*
  * Various sanity checks.
  */
@@ -1087,12 +1042,6 @@ void __cpu_die(unsigned int cpu)
  	printk(KERN_ERR "CPU %u didn't die...\n", cpu);
 }
 
-static __init int setup_additional_cpus(char *s)
-{
-	return s && get_option(&s, &additional_cpus) ? 0 : -EINVAL;
-}
-early_param("additional_cpus", setup_additional_cpus);
-
 #else /* ... !CONFIG_HOTPLUG_CPU */
 
 int __cpu_disable(void)

include/asm-x86/smp.h

@@ -63,6 +63,7 @@ void native_smp_cpus_done(unsigned int max_cpus);
 int native_cpu_up(unsigned int cpunum);
 
 extern unsigned disabled_cpus;
+extern void prefill_possible_map(void);
 #endif
 
 #ifdef CONFIG_X86_32

include/asm-x86/smp_64.h

@@ -43,7 +43,6 @@ static inline int cpu_present_to_apicid(int mps_cpu)
 
 extern int __cpu_disable(void);
 extern void __cpu_die(unsigned int cpu);
-extern void prefill_possible_map(void);
 
 #define raw_smp_processor_id()	read_pda(cpunumber)
 #define cpu_physical_id(cpu)	per_cpu(x86_cpu_to_apicid, cpu)