• Linus Torvalds's avatar
    x86/build: Add -Wnoaddress-of-packed-member to REALMODE_CFLAGS, to silence GCC9 build warning · 42e0e954
    Linus Torvalds authored
    One of the very few warnings I have in the current build comes from
    arch/x86/boot/edd.c, where I get the following with a gcc9 build:
    
       arch/x86/boot/edd.c: In function ‘query_edd’:
       arch/x86/boot/edd.c:148:11: warning: taking address of packed member of ‘struct boot_params’ may result in an unaligned pointer value [-Waddress-of-packed-member]
         148 |  mbrptr = boot_params.edd_mbr_sig_buffer;
             |           ^~~~~~~~~~~
    
    This warning triggers because we throw away all the CFLAGS and then make
    a new set for REALMODE_CFLAGS, so the -Wno-address-of-packed-member we
    added in the following commit is not present:
    
      6f303d60 ("gcc-9: silence 'address-of-packed-member' warning")
    
    The simplest solution for now is to adjust the warning for this version
    of CFLAGS as well, but it would definitely make sense to examine whether
    REALMODE_CFLAGS could be derived from CFLAGS, so that it picks up changes
    in the compiler flags environment automatically.
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    Acked-by: default avatarBorislav Petkov <bp@alien8.de>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
    42e0e954
Makefile 11.7 KB