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>

1 files changed, 13 insertions, 0 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();