5 files changed, 24 insertions, 19 deletions
diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index bfea1bedcbf..b008fb0cd7b 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -737,7 +737,7 @@ config PHYSICAL_START
 
 config HOTPLUG_CPU
 	bool "Support for hot-pluggable CPUs (EXPERIMENTAL)"
-	depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER
+	depends on SMP && HOTPLUG && EXPERIMENTAL && !X86_VOYAGER && !X86_PC
 	---help---
 	  Say Y here to experiment with turning CPUs off and on.  CPUs
 	  can be controlled through /sys/devices/system/cpu.
diff --git a/arch/i386/Kconfig.debug b/arch/i386/Kconfig.debug
index 00108ba9a78..6e97df6979e 100644
--- a/arch/i386/Kconfig.debug
+++ b/arch/i386/Kconfig.debug
@@ -44,8 +44,8 @@ comment "Page alloc debug is incompatible with Software Suspend on i386"
 	depends on DEBUG_KERNEL && SOFTWARE_SUSPEND
 
 config DEBUG_PAGEALLOC
-	bool "Page alloc debugging"
-	depends on DEBUG_KERNEL && !SOFTWARE_SUSPEND
+	bool "Debug page memory allocations"
+	depends on DEBUG_KERNEL && !SOFTWARE_SUSPEND && !HUGETLBFS
 	help
 	  Unmap pages from the kernel linear mapping after free_pages().
 	  This results in a large slowdown, but helps to find certain types
diff --git a/arch/i386/boot/edd.S b/arch/i386/boot/edd.S
index d8d69f2b911..4b84ea216f2 100644
--- a/arch/i386/boot/edd.S
+++ b/arch/i386/boot/edd.S
@@ -76,6 +76,8 @@ edd_mbr_sig_read:
 	popw	%es
 	popw	%bx
 	jc	edd_mbr_sig_done		# on failure, we're done.
+	cmpb	$0, %ah		# some BIOSes do not set CF
+	jne	edd_mbr_sig_done		# on failure, we're done.
 	movl	(EDDBUF+EDD_MBR_SIG_OFFSET), %eax # read sig out of the MBR
 	movl	%eax, (%bx)			# store success
 	incb	(EDD_MBR_SIG_NR_BUF)		# note that we stored something
diff --git a/arch/i386/kernel/dmi_scan.c b/arch/i386/kernel/dmi_scan.c
index 6a93d75db43..ca2a0cbcac0 100644
--- a/arch/i386/kernel/dmi_scan.c
+++ b/arch/i386/kernel/dmi_scan.c
@@ -106,7 +106,7 @@ static void __init dmi_save_devices(struct dmi_header *dm)
 	struct dmi_device *dev;
 
 	for (i = 0; i < count; i++) {
-		char *d = ((char *) dm) + (i * 2);
+		char *d = (char *)(dm + 1) + (i * 2);
 
 		/* Skip disabled device */
 		if ((*d & 0x80) == 0)
diff --git a/arch/i386/kernel/smpboot.c b/arch/i386/kernel/smpboot.c
index 4c470e99a74..82371d83bfa 100644
--- a/arch/i386/kernel/smpboot.c
+++ b/arch/i386/kernel/smpboot.c
@@ -1003,7 +1003,6 @@ void cpu_exit_clear(void)
 
 	cpu_clear(cpu, cpu_callout_map);
 	cpu_clear(cpu, cpu_callin_map);
-	cpu_clear(cpu, cpu_present_map);
 
 	cpu_clear(cpu, smp_commenced_mask);
 	unmap_cpu_to_logical_apicid(cpu);
@@ -1015,31 +1014,20 @@ struct warm_boot_cpu_info {
 	int cpu;
 };
 
-static void __devinit do_warm_boot_cpu(void *p)
+static void __cpuinit do_warm_boot_cpu(void *p)
 {
 	struct warm_boot_cpu_info *info = p;
 	do_boot_cpu(info->apicid, info->cpu);
 	complete(info->complete);
 }
 
-int __devinit smp_prepare_cpu(int cpu)
+static int __cpuinit __smp_prepare_cpu(int cpu)
 {
 	DECLARE_COMPLETION(done);
 	struct warm_boot_cpu_info info;
 	struct work_struct task;
 	int	apicid, ret;
 
-	lock_cpu_hotplug();
-
-	/*
-	 * On x86, CPU0 is never offlined.  Trying to bring up an
-	 * already-booted CPU will hang.  So check for that case.
-	 */
-	if (cpu_online(cpu)) {
-		ret = -EINVAL;
-		goto exit;
-	}
-
 	apicid = x86_cpu_to_apicid[cpu];
 	if (apicid == BAD_APICID) {
 		ret = -ENODEV;
@@ -1064,7 +1052,6 @@ int __devinit smp_prepare_cpu(int cpu)
 	zap_low_mappings();
 	ret = 0;
 exit:
-	unlock_cpu_hotplug();
 	return ret;
 }
 #endif
@@ -1392,6 +1379,22 @@ void __cpu_die(unsigned int cpu)
 
 int __devinit __cpu_up(unsigned int cpu)
 {
+#ifdef CONFIG_HOTPLUG_CPU
+	int ret=0;
+
+	/*
+	 * We do warm boot only on cpus that had booted earlier
+	 * Otherwise cold boot is all handled from smp_boot_cpus().
+	 * cpu_callin_map is set during AP kickstart process. Its reset
+	 * when a cpu is taken offline from cpu_exit_clear().
+	 */
+	if (!cpu_isset(cpu, cpu_callin_map))
+		ret = __smp_prepare_cpu(cpu);
+
+	if (ret)
+		return -EIO;
+#endif
+
 	/* In case one didn't come up */
 	if (!cpu_isset(cpu, cpu_callin_map)) {
 		printk(KERN_DEBUG "skipping cpu%d, didn't come online\n", cpu);