• Linus Torvalds's avatar
    crypto: blake2b: effectively disable frame size warning · 1d3551ce
    Linus Torvalds authored
    It turns out that gcc-12.1 has some nasty problems with register
    allocation on a 32-bit x86 build for the 64-bit values used in the
    generic blake2b implementation, where the pattern of 64-bit rotates and
    xor operations ends up making gcc generate horrible code.
    
    As a result it ends up with a ridiculously large stack frame for all the
    spills it generates, resulting in the following build problem:
    
        crypto/blake2b_generic.c: In function ‘blake2b_compress_one_generic’:
        crypto/blake2b_generic.c:109:1: error: the frame size of 2640 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
    
    on the same test-case, clang ends up generating a stack frame that is
    just 296 bytes (and older gcc versions generate a slightly bigger one at
    428 bytes - still nowhere near that almost 3kB monster stack frame of
    gcc-12.1).
    
    The issue is fixed both in mainline and the GCC 12 release branch [1],
    but current release compilers end up failing the i386 allmodconfig build
    due to this issue.
    
    Disable the warning for now by simply raising the frame size for this
    one file, just to keep this issue from having people turn off WERROR.
    
    Link: https://lore.kernel.org/all/CAHk-=wjxqgeG2op+=W9sqgsWqCYnavC+SRfVyopu9-31S6xw+Q@mail.gmail.com/
    Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105930 [1]
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    1d3551ce
Makefile 8.17 KB