diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index a6efe0a2e9ae..c1c5ccd1937f 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -789,6 +789,22 @@ config X86_MCE
 	  to disable it.  MCE support simply ignores non-MCE processors like
 	  the 386 and 486, so nearly everyone can say Y here.
 
+config X86_OLD_MCE
+	depends on X86_32 && X86_MCE
+	bool "Use legacy machine check code (will go away)"
+	default n
+	select X86_ANCIENT_MCE
+	---help---
+	  Use the old i386 machine check code. This is merely intended for
+	  testing in a transition period. Try this if you run into any machine
+	  check related software problems, but report the problem to
+	  linux-kernel.  When in doubt say no.
+
+config X86_NEW_MCE
+	depends on X86_MCE
+	bool
+	default y if (!X86_OLD_MCE && X86_32) || X86_64
+
 config X86_MCE_INTEL
 	def_bool y
 	prompt "Intel MCE features"
@@ -805,6 +821,15 @@ config X86_MCE_AMD
 	   Additional support for AMD specific MCE features such as
 	   the DRAM Error Threshold.
 
+config X86_ANCIENT_MCE
+       def_bool n
+       depends on X86_32
+       prompt "Support for old Pentium 5 / WinChip machine checks"
+       ---help---
+	 Include support for machine check handling on old Pentium 5 or WinChip
+	 systems. These typically need to be enabled explicitely on the command
+	 line.
+
 config X86_MCE_THRESHOLD
 	depends on X86_MCE_AMD || X86_MCE_INTEL
 	bool
@@ -812,7 +837,7 @@ config X86_MCE_THRESHOLD
 
 config X86_MCE_NONFATAL
 	tristate "Check for non-fatal errors on AMD Athlon/Duron / Intel Pentium 4"
-	depends on X86_32 && X86_MCE
+	depends on X86_OLD_MCE
 	---help---
 	  Enabling this feature starts a timer that triggers every 5 seconds which
 	  will look at the machine check registers to see if anything happened.
@@ -825,11 +850,15 @@ config X86_MCE_NONFATAL
 
 config X86_MCE_P4THERMAL
 	bool "check for P4 thermal throttling interrupt."
-	depends on X86_32 && X86_MCE && (X86_UP_APIC || SMP)
+	depends on X86_OLD_MCE && X86_MCE && (X86_UP_APIC || SMP)
 	---help---
 	  Enabling this feature will cause a message to be printed when the P4
 	  enters thermal throttling.
 
+config X86_THERMAL_VECTOR
+	def_bool y
+	depends on X86_MCE_P4THERMAL || X86_MCE_INTEL
+
 config VM86
 	bool "Enable VM86 support" if EMBEDDED
 	default y
diff --git a/arch/x86/include/asm/entry_arch.h b/arch/x86/include/asm/entry_arch.h
index c2e6bedaf258..486c9e946f5c 100644
--- a/arch/x86/include/asm/entry_arch.h
+++ b/arch/x86/include/asm/entry_arch.h
@@ -52,7 +52,7 @@ BUILD_INTERRUPT(spurious_interrupt,SPURIOUS_APIC_VECTOR)
 BUILD_INTERRUPT(perf_counter_interrupt, LOCAL_PERF_VECTOR)
 #endif
 
-#ifdef CONFIG_X86_MCE_P4THERMAL
+#ifdef CONFIG_X86_THERMAL_VECTOR
 BUILD_INTERRUPT(thermal_interrupt,THERMAL_APIC_VECTOR)
 #endif
 
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index f2870920f246..ad532289ef2e 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -843,7 +843,7 @@ void clear_local_APIC(void)
 	}
 
 	/* lets not touch this if we didn't frob it */
-#if defined(CONFIG_X86_MCE_P4THERMAL) || defined(CONFIG_X86_MCE_INTEL)
+#ifdef CONFIG_X86_THERMAL_VECTOR
 	if (maxlvt >= 5) {
 		v = apic_read(APIC_LVTTHMR);
 		apic_write(APIC_LVTTHMR, v | APIC_LVT_MASKED);
@@ -1962,7 +1962,7 @@ static int lapic_suspend(struct sys_device *dev, pm_message_t state)
 	apic_pm_state.apic_lvterr = apic_read(APIC_LVTERR);
 	apic_pm_state.apic_tmict = apic_read(APIC_TMICT);
 	apic_pm_state.apic_tdcr = apic_read(APIC_TDCR);
-#if defined(CONFIG_X86_MCE_P4THERMAL) || defined(CONFIG_X86_MCE_INTEL)
+#ifdef CONFIG_X86_THERMAL_VECTOR
 	if (maxlvt >= 5)
 		apic_pm_state.apic_thmr = apic_read(APIC_LVTTHMR);
 #endif
diff --git a/arch/x86/kernel/apic/nmi.c b/arch/x86/kernel/apic/nmi.c
index ce4fbfa315a1..c4762276c17e 100644
--- a/arch/x86/kernel/apic/nmi.c
+++ b/arch/x86/kernel/apic/nmi.c
@@ -66,7 +66,7 @@ static inline unsigned int get_nmi_count(int cpu)
 
 static inline int mce_in_progress(void)
 {
-#if defined(CONFIG_X86_64) && defined(CONFIG_X86_MCE)
+#if defined(CONFIG_X86_NEW_MCE)
 	return atomic_read(&mce_entry) > 0;
 #endif
 	return 0;
diff --git a/arch/x86/kernel/cpu/mcheck/Makefile b/arch/x86/kernel/cpu/mcheck/Makefile
index 55f01b39a105..5f8b09425d39 100644
--- a/arch/x86/kernel/cpu/mcheck/Makefile
+++ b/arch/x86/kernel/cpu/mcheck/Makefile
@@ -1,6 +1,7 @@
 obj-y				=  mce.o therm_throt.o
 
-obj-$(CONFIG_X86_32)		+= k7.o p4.o p5.o p6.o winchip.o
+obj-$(CONFIG_X86_OLD_MCE)	+= k7.o p4.o p6.o
+obj-$(CONFIG_X86_ANCIENT_MCE)	+= winchip.o p5.o
 obj-$(CONFIG_X86_MCE_P4THERMAL)	+= mce_intel.o
 obj-$(CONFIG_X86_MCE_INTEL)	+= mce_intel_64.o mce_intel.o
 obj-$(CONFIG_X86_MCE_AMD)	+= mce_amd_64.o
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index f4d6841d2bdf..e193de44ef19 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -52,7 +52,7 @@ void (*machine_check_vector)(struct pt_regs *, long error_code) =
 
 int				mce_disabled;
 
-#ifdef CONFIG_X86_64
+#ifdef CONFIG_X86_NEW_MCE
 
 #define MISC_MCELOG_MINOR	227
 
@@ -662,6 +662,21 @@ static void mce_cpu_quirks(struct cpuinfo_x86 *c)
 	}
 }
 
+static void __cpuinit mce_ancient_init(struct cpuinfo_x86 *c)
+{
+	if (c->x86 != 5)
+		return;
+	switch (c->x86_vendor) {
+	case X86_VENDOR_INTEL:
+		if (mce_p5_enabled())
+			intel_p5_mcheck_init(c);
+		break;
+	case X86_VENDOR_CENTAUR:
+		winchip_mcheck_init(c);
+		break;
+	}
+}
+
 static void mce_cpu_features(struct cpuinfo_x86 *c)
 {
 	switch (c->x86_vendor) {
@@ -695,6 +710,11 @@ static void mce_init_timer(void)
  */
 void __cpuinit mcheck_init(struct cpuinfo_x86 *c)
 {
+	if (mce_disabled)
+		return;
+
+	mce_ancient_init(c);
+
 	if (!mce_available(c))
 		return;
 
@@ -893,6 +913,10 @@ static struct miscdevice mce_log_device = {
  */
 static int __init mcheck_enable(char *str)
 {
+	if (*str == 0)
+		enable_p5_mce();
+	if (*str == '=')
+		str++;
 	if (!strcmp(str, "off"))
 		mce_disabled = 1;
 	else if (!strcmp(str, "bootlog") || !strcmp(str, "nobootlog"))
@@ -900,13 +924,13 @@ static int __init mcheck_enable(char *str)
 	else if (isdigit(str[0]))
 		get_option(&str, &tolerant);
 	else {
-		printk(KERN_INFO "mce= argument %s ignored. Please use /sys\n",
+		printk(KERN_INFO "mce argument %s ignored. Please use /sys\n",
 		       str);
 		return 0;
 	}
 	return 1;
 }
-__setup("mce=", mcheck_enable);
+__setup("mce", mcheck_enable);
 
 /*
  * Sysfs support
@@ -1259,7 +1283,7 @@ static __init int mce_init_device(void)
 
 device_initcall(mce_init_device);
 
-#else /* CONFIG_X86_32: */
+#else /* CONFIG_X86_OLD_MCE: */
 
 int nr_mce_banks;
 EXPORT_SYMBOL_GPL(nr_mce_banks);	/* non-fatal.o */
diff --git a/arch/x86/kernel/cpu/mcheck/mce.h b/arch/x86/kernel/cpu/mcheck/mce.h
index 966ae3c5cb11..84a552b458c8 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.h
+++ b/arch/x86/kernel/cpu/mcheck/mce.h
@@ -1,17 +1,29 @@
 #include <linux/init.h>
 #include <asm/mce.h>
 
+#ifdef CONFIG_X86_OLD_MCE
 void amd_mcheck_init(struct cpuinfo_x86 *c);
 void intel_p4_mcheck_init(struct cpuinfo_x86 *c);
-void intel_p5_mcheck_init(struct cpuinfo_x86 *c);
 void intel_p6_mcheck_init(struct cpuinfo_x86 *c);
-void winchip_mcheck_init(struct cpuinfo_x86 *c);
+#endif
 
+#ifdef CONFIG_X86_ANCIENT_MCE
+void intel_p5_mcheck_init(struct cpuinfo_x86 *c);
+void winchip_mcheck_init(struct cpuinfo_x86 *c);
+extern int mce_p5_enable;
+static inline int mce_p5_enabled(void) { return mce_p5_enable; }
+static inline void enable_p5_mce(void) { mce_p5_enable = 1; }
+#else
+static inline void intel_p5_mcheck_init(struct cpuinfo_x86 *c) {}
+static inline void winchip_mcheck_init(struct cpuinfo_x86 *c) {}
+static inline int mce_p5_enabled(void) { return 0; }
+static inline void enable_p5_mce(void) { }
+#endif
 
 /* Call the installed machine check handler for this CPU setup. */
 extern void (*machine_check_vector)(struct pt_regs *, long error_code);
 
-#ifdef CONFIG_X86_32
+#ifdef CONFIG_X86_OLD_MCE
 
 extern int nr_mce_banks;
 
diff --git a/arch/x86/kernel/cpu/mcheck/p5.c b/arch/x86/kernel/cpu/mcheck/p5.c
index 8812f5441830..015f481ab1b0 100644
--- a/arch/x86/kernel/cpu/mcheck/p5.c
+++ b/arch/x86/kernel/cpu/mcheck/p5.c
@@ -14,6 +14,9 @@
 
 #include "mce.h"
 
+/* By default disabled */
+int		mce_p5_enable;
+
 /* Machine check handler for Pentium class Intel CPUs: */
 static void pentium_machine_check(struct pt_regs *regs, long error_code)
 {
@@ -44,9 +47,11 @@ void intel_p5_mcheck_init(struct cpuinfo_x86 *c)
 	if (!cpu_has(c, X86_FEATURE_MCE))
 		return;
 
+#ifdef CONFIG_X86_OLD_MCE
 	/* Default P5 to off as its often misconnected: */
 	if (mce_disabled != -1)
 		return;
+#endif
 
 	machine_check_vector = pentium_machine_check;
 	/* Make sure the vector pointer is visible before we enable MCEs: */
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index c3fe010d74c8..35eddc9ec99e 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -89,7 +89,7 @@ static int show_other_interrupts(struct seq_file *p, int prec)
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", irq_stats(j)->irq_thermal_count);
 	seq_printf(p, "  Thermal event interrupts\n");
-# ifdef CONFIG_X86_64
+# ifdef CONFIG_X86_MCE_THRESHOLD
 	seq_printf(p, "%*s: ", prec, "THR");
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", irq_stats(j)->irq_threshold_count);
@@ -176,7 +176,7 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
 #endif
 #ifdef CONFIG_X86_MCE
 	sum += irq_stats(cpu)->irq_thermal_count;
-# ifdef CONFIG_X86_64
+# ifdef CONFIG_X86_MCE_THRESHOLD
 	sum += irq_stats(cpu)->irq_threshold_count;
 #endif
 #endif
diff --git a/arch/x86/kernel/irqinit_32.c b/arch/x86/kernel/irqinit_32.c
index 368b0a8836f9..98846e03211e 100644
--- a/arch/x86/kernel/irqinit_32.c
+++ b/arch/x86/kernel/irqinit_32.c
@@ -181,7 +181,7 @@ void __init native_init_IRQ(void)
 	alloc_intr_gate(ERROR_APIC_VECTOR, error_interrupt);
 #endif
 
-#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86_MCE_P4THERMAL)
+#ifdef CONFIG_X86_THERMAL_VECTOR
 	/* thermal monitor LVT interrupt */
 	alloc_intr_gate(THERMAL_APIC_VECTOR, thermal_interrupt);
 #endif
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 14425166b8e3..d0851e3f77eb 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -25,11 +25,11 @@
 #include <asm/ucontext.h>
 #include <asm/i387.h>
 #include <asm/vdso.h>
+#include <asm/mce.h>
 
 #ifdef CONFIG_X86_64
 #include <asm/proto.h>
 #include <asm/ia32_unistd.h>
-#include <asm/mce.h>
 #endif /* CONFIG_X86_64 */
 
 #include <asm/syscall.h>
@@ -857,7 +857,7 @@ static void do_signal(struct pt_regs *regs)
 void
 do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
 {
-#if defined(CONFIG_X86_64) && defined(CONFIG_X86_MCE)
+#ifdef CONFIG_X86_NEW_MCE
 	/* notify userspace of pending MCEs */
 	if (thread_info_flags & _TIF_MCE_NOTIFY)
 		mce_notify_user();
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index a1d288327ff0..ad771f15bddd 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -798,7 +798,8 @@ unsigned long patch_espfix_desc(unsigned long uesp, unsigned long kesp)
 
 	return new_kesp;
 }
-#else
+#endif
+
 asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
 {
 }
@@ -806,7 +807,6 @@ asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
 asmlinkage void __attribute__((weak)) mce_threshold_interrupt(void)
 {
 }
-#endif
 
 /*
  * 'math_state_restore()' saves the current math information in the