diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index fa72a39e5d463a248a5b5a4a18f7860a1cbb8a77..3982357de5b0a9a3d498b6413a0ee5371cb731d4 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -510,8 +510,9 @@ generic_get_free_region(unsigned long base, unsigned long size, int replace_reg)
 static void generic_get_mtrr(unsigned int reg, unsigned long *base,
 			     unsigned long *size, mtrr_type *type)
 {
-	unsigned int mask_lo, mask_hi, base_lo, base_hi;
-	unsigned int tmp, hi;
+	u32 mask_lo, mask_hi, base_lo, base_hi;
+	unsigned int hi;
+	u64 tmp, mask;
 
 	/*
 	 * get_mtrr doesn't need to update mtrr_state, also it could be called
@@ -532,18 +533,18 @@ static void generic_get_mtrr(unsigned int reg, unsigned long *base,
 	rdmsr(MTRRphysBase_MSR(reg), base_lo, base_hi);
 
 	/* Work out the shifted address mask: */
-	tmp = mask_hi << (32 - PAGE_SHIFT) | mask_lo >> PAGE_SHIFT;
-	mask_lo = size_or_mask | tmp;
+	tmp = (u64)mask_hi << (32 - PAGE_SHIFT) | mask_lo >> PAGE_SHIFT;
+	mask = size_or_mask | tmp;
 
 	/* Expand tmp with high bits to all 1s: */
-	hi = fls(tmp);
+	hi = fls64(tmp);
 	if (hi > 0) {
-		tmp |= ~((1<<(hi - 1)) - 1);
+		tmp |= ~((1ULL<<(hi - 1)) - 1);
 
-		if (tmp != mask_lo) {
+		if (tmp != mask) {
 			printk(KERN_WARNING "mtrr: your BIOS has configured an incorrect mask, fixing it.\n");
 			add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
-			mask_lo = tmp;
+			mask = tmp;
 		}
 	}
 
@@ -551,8 +552,8 @@ static void generic_get_mtrr(unsigned int reg, unsigned long *base,
 	 * This works correctly if size is a power of two, i.e. a
 	 * contiguous range:
 	 */
-	*size = -mask_lo;
-	*base = base_hi << (32 - PAGE_SHIFT) | base_lo >> PAGE_SHIFT;
+	*size = -mask;
+	*base = (u64)base_hi << (32 - PAGE_SHIFT) | base_lo >> PAGE_SHIFT;
 	*type = base_lo & 0xff;
 
 out_put_cpu:
diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index 726bf963c2276569c39c67377b64fd7a74fb539e..ca22b73aaa25f8c4d512a62161bf6af92ec0807f 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -305,7 +305,8 @@ int mtrr_add_page(unsigned long base, unsigned long size,
 		return -EINVAL;
 	}
 
-	if (base & size_or_mask || size & size_or_mask) {
+	if ((base | (base + size - 1)) >>
+	    (boot_cpu_data.x86_phys_bits - PAGE_SHIFT)) {
 		pr_warning("mtrr: base or size exceeds the MTRR width\n");
 		return -EINVAL;
 	}
@@ -583,6 +584,7 @@ static struct syscore_ops mtrr_syscore_ops = {
 
 int __initdata changed_by_mtrr_cleanup;
 
+#define SIZE_OR_MASK_BITS(n)  (~((1ULL << ((n) - PAGE_SHIFT)) - 1))
 /**
  * mtrr_bp_init - initialize mtrrs on the boot CPU
  *
@@ -600,7 +602,7 @@ void __init mtrr_bp_init(void)
 
 	if (cpu_has_mtrr) {
 		mtrr_if = &generic_mtrr_ops;
-		size_or_mask = 0xff000000;			/* 36 bits */
+		size_or_mask = SIZE_OR_MASK_BITS(36);
 		size_and_mask = 0x00f00000;
 		phys_addr = 36;
 
@@ -619,7 +621,7 @@ void __init mtrr_bp_init(void)
 			     boot_cpu_data.x86_mask == 0x4))
 				phys_addr = 36;
 
-			size_or_mask = ~((1ULL << (phys_addr - PAGE_SHIFT)) - 1);
+			size_or_mask = SIZE_OR_MASK_BITS(phys_addr);
 			size_and_mask = ~size_or_mask & 0xfffff00000ULL;
 		} else if (boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR &&
 			   boot_cpu_data.x86 == 6) {
@@ -627,7 +629,7 @@ void __init mtrr_bp_init(void)
 			 * VIA C* family have Intel style MTRRs,
 			 * but don't support PAE
 			 */
-			size_or_mask = 0xfff00000;		/* 32 bits */
+			size_or_mask = SIZE_OR_MASK_BITS(32);
 			size_and_mask = 0;
 			phys_addr = 32;
 		}
@@ -637,21 +639,21 @@ void __init mtrr_bp_init(void)
 			if (cpu_has_k6_mtrr) {
 				/* Pre-Athlon (K6) AMD CPU MTRRs */
 				mtrr_if = mtrr_ops[X86_VENDOR_AMD];
-				size_or_mask = 0xfff00000;	/* 32 bits */
+				size_or_mask = SIZE_OR_MASK_BITS(32);
 				size_and_mask = 0;
 			}
 			break;
 		case X86_VENDOR_CENTAUR:
 			if (cpu_has_centaur_mcr) {
 				mtrr_if = mtrr_ops[X86_VENDOR_CENTAUR];
-				size_or_mask = 0xfff00000;	/* 32 bits */
+				size_or_mask = SIZE_OR_MASK_BITS(32);
 				size_and_mask = 0;
 			}
 			break;
 		case X86_VENDOR_CYRIX:
 			if (cpu_has_cyrix_arr) {
 				mtrr_if = mtrr_ops[X86_VENDOR_CYRIX];
-				size_or_mask = 0xfff00000;	/* 32 bits */
+				size_or_mask = SIZE_OR_MASK_BITS(32);
 				size_and_mask = 0;
 			}
 			break;