diff --git a/lib/ioremap.c b/lib/ioremap.c
index 517f585..0a2ffad 100644
--- a/lib/ioremap.c
+++ b/lib/ioremap.c
@@ -30,6 +30,8 @@
 void __init ioremap_huge_init(void)
 {
 	if (!ioremap_huge_disabled) {
+		if (arch_ioremap_p4d_supported())
+			ioremap_p4d_capable = 1;
 		if (arch_ioremap_pud_supported())
 			ioremap_pud_capable = 1;
 		if (arch_ioremap_pmd_supported())
@@ -76,83 +78,132 @@
 	return 0;
 }
 
+static int ioremap_try_huge_pmd(pmd_t *pmd, unsigned long addr,
+				unsigned long end, phys_addr_t phys_addr,
+				pgprot_t prot)
+{
+	if (!ioremap_pmd_enabled())
+		return 0;
+
+	if ((end - addr) != PMD_SIZE)
+		return 0;
+
+	if (!IS_ALIGNED(addr, PMD_SIZE))
+		return 0;
+
+	if (!IS_ALIGNED(phys_addr, PMD_SIZE))
+		return 0;
+
+	if (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr))
+		return 0;
+
+	return pmd_set_huge(pmd, phys_addr, prot);
+}
+
 static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
 		unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
 {
 	pmd_t *pmd;
 	unsigned long next;
 
-	phys_addr -= addr;
 	pmd = pmd_alloc(&init_mm, pud, addr);
 	if (!pmd)
 		return -ENOMEM;
 	do {
 		next = pmd_addr_end(addr, end);
 
-		if (ioremap_pmd_enabled() &&
-		    ((next - addr) == PMD_SIZE) &&
-		    IS_ALIGNED(phys_addr + addr, PMD_SIZE) &&
-		    pmd_free_pte_page(pmd, addr)) {
-			if (pmd_set_huge(pmd, phys_addr + addr, prot))
-				continue;
-		}
+		if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr, prot))
+			continue;
 
-		if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, prot))
+		if (ioremap_pte_range(pmd, addr, next, phys_addr, prot))
 			return -ENOMEM;
-	} while (pmd++, addr = next, addr != end);
+	} while (pmd++, phys_addr += (next - addr), addr = next, addr != end);
 	return 0;
 }
 
+static int ioremap_try_huge_pud(pud_t *pud, unsigned long addr,
+				unsigned long end, phys_addr_t phys_addr,
+				pgprot_t prot)
+{
+	if (!ioremap_pud_enabled())
+		return 0;
+
+	if ((end - addr) != PUD_SIZE)
+		return 0;
+
+	if (!IS_ALIGNED(addr, PUD_SIZE))
+		return 0;
+
+	if (!IS_ALIGNED(phys_addr, PUD_SIZE))
+		return 0;
+
+	if (pud_present(*pud) && !pud_free_pmd_page(pud, addr))
+		return 0;
+
+	return pud_set_huge(pud, phys_addr, prot);
+}
+
 static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr,
 		unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
 {
 	pud_t *pud;
 	unsigned long next;
 
-	phys_addr -= addr;
 	pud = pud_alloc(&init_mm, p4d, addr);
 	if (!pud)
 		return -ENOMEM;
 	do {
 		next = pud_addr_end(addr, end);
 
-		if (ioremap_pud_enabled() &&
-		    ((next - addr) == PUD_SIZE) &&
-		    IS_ALIGNED(phys_addr + addr, PUD_SIZE) &&
-		    pud_free_pmd_page(pud, addr)) {
-			if (pud_set_huge(pud, phys_addr + addr, prot))
-				continue;
-		}
+		if (ioremap_try_huge_pud(pud, addr, next, phys_addr, prot))
+			continue;
 
-		if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, prot))
+		if (ioremap_pmd_range(pud, addr, next, phys_addr, prot))
 			return -ENOMEM;
-	} while (pud++, addr = next, addr != end);
+	} while (pud++, phys_addr += (next - addr), addr = next, addr != end);
 	return 0;
 }
 
+static int ioremap_try_huge_p4d(p4d_t *p4d, unsigned long addr,
+				unsigned long end, phys_addr_t phys_addr,
+				pgprot_t prot)
+{
+	if (!ioremap_p4d_enabled())
+		return 0;
+
+	if ((end - addr) != P4D_SIZE)
+		return 0;
+
+	if (!IS_ALIGNED(addr, P4D_SIZE))
+		return 0;
+
+	if (!IS_ALIGNED(phys_addr, P4D_SIZE))
+		return 0;
+
+	if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))
+		return 0;
+
+	return p4d_set_huge(p4d, phys_addr, prot);
+}
+
 static inline int ioremap_p4d_range(pgd_t *pgd, unsigned long addr,
 		unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
 {
 	p4d_t *p4d;
 	unsigned long next;
 
-	phys_addr -= addr;
 	p4d = p4d_alloc(&init_mm, pgd, addr);
 	if (!p4d)
 		return -ENOMEM;
 	do {
 		next = p4d_addr_end(addr, end);
 
-		if (ioremap_p4d_enabled() &&
-		    ((next - addr) == P4D_SIZE) &&
-		    IS_ALIGNED(phys_addr + addr, P4D_SIZE)) {
-			if (p4d_set_huge(p4d, phys_addr + addr, prot))
-				continue;
-		}
+		if (ioremap_try_huge_p4d(p4d, addr, next, phys_addr, prot))
+			continue;
 
-		if (ioremap_pud_range(p4d, addr, next, phys_addr + addr, prot))
+		if (ioremap_pud_range(p4d, addr, next, phys_addr, prot))
 			return -ENOMEM;
-	} while (p4d++, addr = next, addr != end);
+	} while (p4d++, phys_addr += (next - addr), addr = next, addr != end);
 	return 0;
 }
 
@@ -168,14 +219,13 @@
 	BUG_ON(addr >= end);
 
 	start = addr;
-	phys_addr -= addr;
 	pgd = pgd_offset_k(addr);
 	do {
 		next = pgd_addr_end(addr, end);
-		err = ioremap_p4d_range(pgd, addr, next, phys_addr+addr, prot);
+		err = ioremap_p4d_range(pgd, addr, next, phys_addr, prot);
 		if (err)
 			break;
-	} while (pgd++, addr = next, addr != end);
+	} while (pgd++, phys_addr += (next - addr), addr = next, addr != end);
 
 	flush_cache_vmap(start, end);