realmode _WAKEUP

Paul Bolle pebolle at
Wed Jan 7 11:54:10 EST 2015

On Wed, 2015-01-07 at 20:12 +0600, Alexander Kuleshov wrote:
> There is following definition at arch/x86/realmode/rm/Makefile:
>            -I$(srctree)/arch/x86/boot
> Is it used now? I'm asking because _WAKEUP definition everywhere
> undefined in the code.

git grep tells me:
    $ git grep -n "_WAKEUP\b" arch/x86
    arch/x86/boot/video-bios.c:51:#ifndef _WAKEUP
    arch/x86/boot/video-bios.c:66:#ifdef _WAKEUP
    arch/x86/boot/video-mode.c:169:#ifndef _WAKEUP
    arch/x86/boot/video-vesa.c:27:#ifndef _WAKEUP
    arch/x86/boot/video-vesa.c:29:#else /* _WAKEUP */
    arch/x86/boot/video-vesa.c:31:#endif /* _WAKEUP */
    arch/x86/boot/video-vesa.c:160:#ifndef _WAKEUP
    arch/x86/boot/video-vesa.c:272:#endif /* not _WAKEUP */
    arch/x86/boot/video-vga.c:257:#ifndef _WAKEUP
    arch/x86/boot/video-vga.c:269:#ifndef _WAKEUP

And in that Makefile we also see, a few lines up:
    wakeup-objs     := [...] video-mode.o
    wakeup-objs     += video-vga.o
    wakeup-objs     += video-vesa.o
    wakeup-objs     += video-bios.o

So this Makefile line defines a _WAKEUP macro that is, it seems, used
for the build of those four object files. (It's bit more complicated
than that. But I think KBUILD_CFLAGS is explained in Documentation/,
isn't it?)

Hope this helps,

Paul Bolle

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