x86: check vmlinux limits, 64-bit

these build-time and link-time checks would have prevented the
vmlinux size regression.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 19 insertions, 4 deletions

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index ad2440832de0..38f32e798a99 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -82,6 +82,19 @@ void __init x86_64_start_kernel(char * real_mode_data)
 {
         int i;
 
+        /*
+         * Build-time sanity checks on the kernel image and module
+         * area mappings. (these are purely build-time and produce no code)
+         */
+        BUILD_BUG_ON(MODULES_VADDR < KERNEL_IMAGE_START);
+        BUILD_BUG_ON(MODULES_VADDR-KERNEL_IMAGE_START < KERNEL_IMAGE_SIZE);
+        BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
+        BUILD_BUG_ON((KERNEL_IMAGE_START & ~PMD_MASK) != 0);
+        BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
+        BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
+        BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
+                                (__START_KERNEL & PGDIR_MASK)));
+
         /* clear bss before set_intr_gate with early_idt_handler */
         clear_bss();
 
diff --git a/arch/x86/kernel/vmlinux_64.lds.S b/arch/x86/kernel/vmlinux_64.lds.S
index fab132299735..4c369451007b 100644
--- a/arch/x86/kernel/vmlinux_64.lds.S
+++ b/arch/x86/kernel/vmlinux_64.lds.S
@@ -247,3 +247,9 @@ SECTIONS
 
   DWARF_DEBUG
 }
+
+/*
+ * Build-time check on the image size:
+ */
+ASSERT((_end - _text <= KERNEL_IMAGE_SIZE),
+        "kernel image bigger than KERNEL_IMAGE_SIZE")
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index ec08d8389850..81fcbeec3892 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -976,9 +976,5 @@ void vmalloc_sync_all(void)
                 if (address == start)
                         start = address + PGDIR_SIZE;
         }
-        /* Check that there is no need to do the same for the modules area. */
-        BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
-        BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
-                                (__START_KERNEL & PGDIR_MASK)));
 #endif
 }