diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index eb415043a9297d742f3df5d9a1de10fa35d0b69b..b037b15be7f88b4bd1d20ea5fc54ab3a5234b127 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -379,18 +379,24 @@ NEXT_PAGE(level2_ident_pgt)
 	/* Since I easily can, map the first 1G.
 	 * Don't set NX because code runs from these pages.
 	 */
-	PMDS(0x0000000000000000, __PAGE_KERNEL_LARGE_EXEC, PTRS_PER_PMD)
+	PMDS(0, __PAGE_KERNEL_LARGE_EXEC, PTRS_PER_PMD)
 
 NEXT_PAGE(level2_kernel_pgt)
-	/* 40MB kernel mapping. The kernel code cannot be bigger than that.
-	   When you change this change KERNEL_TEXT_SIZE in page.h too. */
-	/* (2^48-(2*1024*1024*1024)-((2^39)*511)-((2^30)*510)) = 0 */
-	PMDS(0x0000000000000000, __PAGE_KERNEL_LARGE_EXEC|_PAGE_GLOBAL, KERNEL_TEXT_SIZE/PMD_SIZE)
-	/* Module mapping starts here */
-	.fill	(PTRS_PER_PMD - (KERNEL_TEXT_SIZE/PMD_SIZE)),8,0
+	/*
+	 * 128 MB kernel mapping. We spend a full page on this pagetable
+	 * anyway.
+	 *
+	 * The kernel code+data+bss must not be bigger than that.
+	 *
+	 * (NOTE: at +128MB starts the module area, see MODULES_VADDR.
+	 *  If you want to increase this then increase MODULES_VADDR
+	 *  too.)
+	 */
+	PMDS(0, __PAGE_KERNEL_LARGE_EXEC|_PAGE_GLOBAL,
+		KERNEL_TEXT_SIZE/PMD_SIZE)
 
 NEXT_PAGE(level2_spare_pgt)
-	.fill   512,8,0
+	.fill   512, 8, 0
 
 #undef PMDS
 #undef NEXT_PAGE
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 6dbb0035c57aa7c4059f0b157ed7ec1bfbe6f659..a02a14f0f324f9a3392810a46d587dfcda23a157 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -172,8 +172,9 @@ set_pte_phys(unsigned long vaddr, unsigned long phys, pgprot_t prot)
 }
 
 /*
- * The head.S code sets up the kernel high mapping from:
- * __START_KERNEL_map to __START_KERNEL_map + KERNEL_TEXT_SIZE
+ * The head.S code sets up the kernel high mapping:
+ *
+ *   from __START_KERNEL_map to __START_KERNEL_map + size (== _end-_text)
  *
  * phys_addr holds the negative offset to the kernel, which is added
  * to the compile time generated pmds. This results in invalid pmds up
diff --git a/include/asm-x86/page_64.h b/include/asm-x86/page_64.h
index f7393bc516eff1c1d25ad799f0441f734a151280..3e2e3ca63048790b662ac24961250929a0d71fac 100644
--- a/include/asm-x86/page_64.h
+++ b/include/asm-x86/page_64.h
@@ -47,8 +47,12 @@
 #define __PHYSICAL_MASK_SHIFT	46
 #define __VIRTUAL_MASK_SHIFT	48
 
-#define KERNEL_TEXT_SIZE  (40*1024*1024)
-#define KERNEL_TEXT_START _AC(0xffffffff80000000, UL)
+/*
+ * Kernel image size is limited to 128 MB (see level2_kernel_pgt in
+ * arch/x86/kernel/head_64.S), and it is mapped here:
+ */
+#define KERNEL_TEXT_SIZE	(128*1024*1024)
+#define KERNEL_TEXT_START	_AC(0xffffffff80000000, UL)
 
 #ifndef __ASSEMBLY__
 void clear_page(void *page);