From 069f11f9d66bc582fb40a37a7b92363f5d321969 Mon Sep 17 00:00:00 2001 From: Vivek Goyal Date: Thu, 10 May 2007 22:22:15 -0700 Subject: x86_64: display more intuitive error message if kernel is not 2MB aligned o x86_64 kernel needs to be compiled for 2MB aligned addresses. Currently we are using BUILD_BUG_ON() to warn the user if he has not done so. But looks like folks are not finding message very intutive and don't open the respective c file to find problem source. (Bug 8439) arch/x86_64/kernel/head64.c: In function 'x86_64_start_kernel': arch/x86_64/kernel/head64.c:70: error: size of array 'type name' is negative o Using preprocessor directive #error to print a better message if CONFIG_PHYSICAL_START is not aligned to 2MB boundary. Signed-off-by: Vivek Goyal Cc: Andi Kleen Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-x86_64/page.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include') diff --git a/include/asm-x86_64/page.h b/include/asm-x86_64/page.h index dee632f..e327c83 100644 --- a/include/asm-x86_64/page.h +++ b/include/asm-x86_64/page.h @@ -80,6 +80,15 @@ extern unsigned long phys_base; #define __PHYSICAL_START CONFIG_PHYSICAL_START #define __KERNEL_ALIGN 0x200000 +/* + * Make sure kernel is aligned to 2MB address. Catching it at compile + * time is better. Change your config file and compile the kernel + * for a 2MB aligned address (CONFIG_PHYSICAL_START) + */ +#if (CONFIG_PHYSICAL_START % __KERNEL_ALIGN) != 0 +#error "CONFIG_PHYSICAL_START must be a multiple of 2MB" +#endif + #define __START_KERNEL (__START_KERNEL_map + __PHYSICAL_START) #define __START_KERNEL_map _AC(0xffffffff80000000, UL) #define __PAGE_OFFSET _AC(0xffff810000000000, UL) -- cgit v1.1