• Taras Kondratiuk's avatar
    ARM: kprobes-test: Workaround GAS .align bug · 41b5368f
    Taras Kondratiuk authored
    By default if no fill symbol is given to .align directive in a code
    section it fills gap with NOPs. If previous fragment is not
    instruction-aligned, additional pre-alignment is done by zero bytes
    before NOPs. These zero bytes are marked as data by special symbol $d in
    symbol table. Unfortunately GAS assumes that there is only code in the
    code section so it "puts back" code symbol $a at the end of this
    pre-alignment. So if there is some data after alignment it will be
    interpreted as code and will be swapped back to LE for BE8 system during
    a final linking.
    
    If explicit fill value is given to .align, the NOP-padding code is
    skipped and symbol table does not get messed-up.
    
    So the workaround for this issue:
    Use explicit fill value if data should be aligned in the code section.
    Acked-by: default avatarBen Dooks <ben.dooks@codethink.co.uk>
    Acked-by: default avatarJon Medhurst <tixy@linaro.org>
    Signed-off-by: default avatarTaras Kondratiuk <taras.kondratiuk@linaro.org>
    41b5368f
kprobes-test.h 11.5 KB