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authorVivek Goyal <vgoyal@in.ibm.com>2007-05-10 22:22:15 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-11 08:29:32 -0700
commit069f11f9d66bc582fb40a37a7b92363f5d321969 (patch)
tree70d07076d1026fedfeaa9a4cdf04ba1b3cf9aad6 /include/asm-x86_64/page.h
parent6041b57c6c99dcb59524f1bb0db0628c2689a464 (diff)
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 <vgoyal@in.ibm.com> Cc: Andi Kleen <ak@suse.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/asm-x86_64/page.h')
-rw-r--r--include/asm-x86_64/page.h9
1 files changed, 9 insertions, 0 deletions
diff --git a/include/asm-x86_64/page.h b/include/asm-x86_64/page.h
index dee632fa457..e327c830da0 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)