x86, boot: Use __attribute__((used)) to ensure videocard structs are emitted

It looks like GCC will always emit an object that is marked with an
explicit section, although the documentation doesn't say that and we
possibly shouldn't be relying on it.

Clang does *not* do so, so add __attribute__((used)) to make sure.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Link: http://lkml.kernel.org/r/1389180083-23249-2-git-send-email-David.Woodhouse@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

diff --git a/arch/x86/boot/video.h b/arch/x86/boot/video.h
index ff339c5db31127c7db4e27d9e16c32d1d3d0753d..0bb25491262d00f941001d3f7f7b2fc800212250 100644 (file)
--- a/arch/x86/boot/video.h
+++ b/arch/x86/boot/video.h
@@ -80,7 +80,7 @@ struct card_info {
        u16 xmode_n;            /* Size of unprobed mode range */
 };
 
-#define __videocard struct card_info __attribute__((section(".videocards")))
+#define __videocard struct card_info __attribute__((used,section(".videocards")))
 extern struct card_info video_cards[], video_cards_end[];
 
 int mode_defined(u16 mode);    /* video.c */