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  • Rikard Falkeborn's avatar
    x86/boot: Use common BUILD_BUG_ON · d5a1badd
    Rikard Falkeborn authored
    Defining BUILD_BUG_ON causes redefinition warnings when adding includes of
    include/linux/build_bug.h in files unrelated to x86/boot.  For example,
    adding an include of build_bug.h to include/linux/bits.h shows the
    following warnings:
      CC      arch/x86/boot/cpucheck.o
      In file included from ./include/linux/bits.h:22,
                       from ./arch/x86/include/asm/msr-index.h:5,
                       from arch/x86/boot/cpucheck.c:28:
      ./include/linux/build_bug.h:49: warning: "BUILD_BUG_ON" redefined
         49 | #define BUILD_BUG_ON(condition) \
      In file included from arch/x86/boot/cpucheck.c:22:
      arch/x86/boot/boot.h:31: note: this is the location of the previous definition
         31 | #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
    The macro was added to boot.h in commit 62bd0337
     ("Top header file for
    new x86 setup code"). At that time, BUILD_BUG_ON was defined in
    kernel.h. Presumably BUILD_BUG_ON was redefined to avoid pulling in
    kernel.h. Since then, BUILD_BUG_ON and similar macros have been split to a
    separate header file.
    Signed-off-by: default avatarRikard Falkeborn <>
    Signed-off-by: default avatarThomas Gleixner <>
    Reviewed-by: default avatarKees Cook <>