• Peter Jones's avatar
    mkimage: avoid copying relocations for sections that won't be copied. · ebc825b5
    Peter Jones authored
    Some versions of gcc include a plugin called "annobin", and in some
    build systems this is enabled by default.  This plugin creates special
    ELF note sections to track which ABI-breaking features are used by a
    binary, as well as a series of relocations to annotate where.
    
    If grub is compiled with this feature, then when grub-mkimage translates
    the binary to another file format which does not strongly associate
    relocation data with sections (i.e. when platform is *-efi), these
    relocations appear to be against the .text section rather than the
    original note section.  When the binary is loaded by the PE runtime
    loader, hilarity ensues.
    
    This issue is not necessarily limited to the annobin, but could arise
    any time there are relocations in sections that are not represented in
    grub-mkimage's output.
    
    This patch seeks to avoid this issue by only including relocations that
    refer to sections which will be included in the final binary.
    
    As an aside, this should also obviate the need to avoid -funwind-tables,
    -fasynchronous-unwind-tables, and any sections similar to .eh_frame in
    the future.  I've tested it on x86-64-efi with the following gcc command
    line options (as recorded by -grecord-gcc-flags), but I still need to
    test the result on some other platforms that have been problematic in
    the past (especially ARM Aarch64) before I feel comfortable making
    changes to the configure.ac bits:
    
    GNU C11 7.2.1 20180116 (Red Hat 7.2.1-7) -mno-mmx -mno-sse -mno-sse2 -mno-sse3 -mno-3dnow -msoft-float -mno-stack-arg-probe -mcmodel=large -mno-red-zone -m64 -mtune=generic -march=x86-64 -g3 -Os -freg-struct-return -fno-stack-protector -ffreestanding -funwind-tables -fasynchronous-unwind-tables -fno-strict-aliasing -fstack-clash-protection -fno-ident -fplugin=annobin
    Signed-off-by: default avatarPeter Jones <pjones@redhat.com>
    Reviewed-by: default avatarDaniel Kiper <daniel.kiper@oracle.com>
    ebc825b5
grub-mkimagexx.c 67 KB