diff --git a/arch/x86_64/kernel/head.S b/arch/x86_64/kernel/head.S
index b92e5f4..1529096 100644
--- a/arch/x86_64/kernel/head.S
+++ b/arch/x86_64/kernel/head.S
@@ -12,6 +12,7 @@
 
 #include <linux/linkage.h>
 #include <linux/threads.h>
+#include <linux/init.h>
 #include <asm/desc.h>
 #include <asm/segment.h>
 #include <asm/page.h>
@@ -70,7 +71,7 @@
 	movl	%eax, %cr4
 
 	/* Setup early boot stage 4 level pagetables */
-	movl	$(init_level4_pgt - __START_KERNEL_map), %eax
+	movl	$(boot_level4_pgt - __START_KERNEL_map), %eax
 	movl	%eax, %cr3
 
 	/* Setup EFER (Extended Feature Enable Register) */
@@ -113,7 +114,7 @@
 	movq	%rax, %cr4
 
 	/* Setup early boot stage 4 level pagetables. */
-	movq	$(init_level4_pgt - __START_KERNEL_map), %rax
+	movq	$(boot_level4_pgt - __START_KERNEL_map), %rax
 	movq	%rax, %cr3
 
 	/* Check if nx is implemented */
@@ -240,20 +241,10 @@
 ENTRY(stext)
 ENTRY(_stext)
 
-	/*
-	 * This default setting generates an ident mapping at address 0x100000
-	 * and a mapping for the kernel that precisely maps virtual address
-	 * 0xffffffff80000000 to physical address 0x000000. (always using
-	 * 2Mbyte large pages provided by PAE mode)
-	 */
 .org 0x1000
 ENTRY(init_level4_pgt)
-	.quad	0x0000000000002007 + __PHYSICAL_START	/* -> level3_ident_pgt */
-	.fill	255,8,0
-	.quad	0x000000000000a007 + __PHYSICAL_START
-	.fill	254,8,0
-	/* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
-	.quad	0x0000000000003007 + __PHYSICAL_START	/* -> level3_kernel_pgt */
+	/* This gets initialized in x86_64_start_kernel */
+	.fill	512,8,0
 
 .org 0x2000
 ENTRY(level3_ident_pgt)
@@ -350,6 +341,24 @@
 	.quad	0x0000000000003007 + __PHYSICAL_START	/* -> level3_kernel_pgt */
 #endif
 
+#ifndef CONFIG_HOTPLUG_CPU
+	__INITDATA
+#endif
+	/*
+	 * This default setting generates an ident mapping at address 0x100000
+	 * and a mapping for the kernel that precisely maps virtual address
+	 * 0xffffffff80000000 to physical address 0x000000. (always using
+	 * 2Mbyte large pages provided by PAE mode)
+	 */
+	.align PAGE_SIZE
+ENTRY(boot_level4_pgt)
+	.quad	0x0000000000002007 + __PHYSICAL_START	/* -> level3_ident_pgt */
+	.fill	255,8,0
+	.quad	0x000000000000a007 + __PHYSICAL_START
+	.fill	254,8,0
+	/* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
+	.quad	0x0000000000003007 + __PHYSICAL_START	/* -> level3_kernel_pgt */
+
 	.data
 
 	.align 16
diff --git a/arch/x86_64/kernel/head64.c b/arch/x86_64/kernel/head64.c
index cf6ab14..e0f12d4 100644
--- a/arch/x86_64/kernel/head64.c
+++ b/arch/x86_64/kernel/head64.c
@@ -19,6 +19,7 @@
 #include <asm/bootsetup.h>
 #include <asm/setup.h>
 #include <asm/desc.h>
+#include <asm/pgtable.h>
 
 /* Don't add a printk in there. printk relies on the PDA which is not initialized 
    yet. */
@@ -86,6 +87,13 @@
 		set_intr_gate(i, early_idt_handler);
 	asm volatile("lidt %0" :: "m" (idt_descr));
 	clear_bss();
+
+	/*
+	 * switch to init_level4_pgt from boot_level4_pgt
+	 */
+	memcpy(init_level4_pgt, boot_level4_pgt, PTRS_PER_PGD*sizeof(pgd_t));
+	asm volatile("movq %0,%%cr3" :: "r" (__pa_symbol(&init_level4_pgt)));
+
 	pda_init(0);
 	copy_bootdata(real_mode_data);
 #ifdef CONFIG_SMP
diff --git a/arch/x86_64/kernel/mpparse.c b/arch/x86_64/kernel/mpparse.c
index 8f6958e..4a581d1 100644
--- a/arch/x86_64/kernel/mpparse.c
+++ b/arch/x86_64/kernel/mpparse.c
@@ -549,7 +549,7 @@
 		 * Read the physical hardware table.  Anything here will
 		 * override the defaults.
 		 */
-		if (!smp_read_mpc((void *)(unsigned long)mpf->mpf_physptr)) {
+		if (!smp_read_mpc(phys_to_virt(mpf->mpf_physptr))) {
 			smp_found_config = 0;
 			printk(KERN_ERR "BIOS bug, MP table errors detected!...\n");
 			printk(KERN_ERR "... disabling SMP support. (tell your hw vendor)\n");
diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c
index 99cfa75..f76f374 100644
--- a/arch/x86_64/kernel/setup.c
+++ b/arch/x86_64/kernel/setup.c
@@ -571,6 +571,8 @@
 
 	init_memory_mapping(0, (end_pfn_map << PAGE_SHIFT));
 
+	zap_low_mappings(0);
+
 #ifdef CONFIG_ACPI
 	/*
 	 * Initialize the ACPI boot-time table parser (gets the RSDP and SDT).
diff --git a/arch/x86_64/kernel/setup64.c b/arch/x86_64/kernel/setup64.c
index 7919089..06dc354 100644
--- a/arch/x86_64/kernel/setup64.c
+++ b/arch/x86_64/kernel/setup64.c
@@ -141,7 +141,6 @@
 			panic("cannot allocate irqstack for cpu %d", cpu); 
 	}
 
-	asm volatile("movq %0,%%cr3" :: "r" (__pa_symbol(&init_level4_pgt)));
 
 	pda->irqstackptr += IRQSTACKSIZE-64;
 } 
@@ -197,6 +196,7 @@
 	/* CPU 0 is initialised in head64.c */
 	if (cpu != 0) {
 		pda_init(cpu);
+		zap_low_mappings(cpu);
 	} else 
 		estacks = boot_exception_stacks; 
 
diff --git a/arch/x86_64/kernel/smpboot.c b/arch/x86_64/kernel/smpboot.c
index 658a81b..3393fc0 100644
--- a/arch/x86_64/kernel/smpboot.c
+++ b/arch/x86_64/kernel/smpboot.c
@@ -1063,9 +1063,6 @@
  */
 void __init smp_cpus_done(unsigned int max_cpus)
 {
-#ifndef CONFIG_HOTPLUG_CPU
-	zap_low_mappings();
-#endif
 	smp_cleanup_boot();
 
 #ifdef CONFIG_X86_IO_APIC
diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index 2b1d6c3..be483a1 100644
--- a/arch/x86_64/mm/init.c
+++ b/arch/x86_64/mm/init.c
@@ -312,12 +312,19 @@
 
 extern struct x8664_pda cpu_pda[NR_CPUS];
 
-/* Assumes all CPUs still execute in init_mm */
-void zap_low_mappings(void)
+void __cpuinit zap_low_mappings(int cpu)
 {
-	pgd_t *pgd = pgd_offset_k(0UL);
-	pgd_clear(pgd);
-	flush_tlb_all();
+	if (cpu == 0) {
+		pgd_t *pgd = pgd_offset_k(0UL);
+		pgd_clear(pgd);
+	} else {
+		/*
+		 * For AP's, zap the low identity mappings by changing the cr3
+		 * to init_level4_pgt and doing local flush tlb all
+		 */
+		asm volatile("movq %0,%%cr3" :: "r" (__pa_symbol(&init_level4_pgt)));
+	}
+	__flush_tlb_all();
 }
 
 /* Compute zone sizes for the DMA and DMA32 zones in a node. */
@@ -474,14 +481,13 @@
 		datasize >> 10,
 		initsize >> 10);
 
+#ifdef CONFIG_SMP
 	/*
-	 * Subtle. SMP is doing its boot stuff late (because it has to
-	 * fork idle threads) - but it also needs low mappings for the
-	 * protected-mode entry to work. We zap these entries only after
-	 * the WP-bit has been tested.
+	 * Sync boot_level4_pgt mappings with the init_level4_pgt
+	 * except for the low identity mappings which are already zapped
+	 * in init_level4_pgt. This sync-up is essential for AP's bringup
 	 */
-#ifndef CONFIG_SMP
-	zap_low_mappings();
+	memcpy(boot_level4_pgt+1, init_level4_pgt+1, (PTRS_PER_PGD-1)*sizeof(pgd_t));
 #endif
 }