• Martin Schwidefsky's avatar
    [S390] Remove data execution protection · 043d0708
    Martin Schwidefsky authored
    The noexec support on s390 does not rely on a bit in the page table
    entry but utilizes the secondary space mode to distinguish between
    memory accesses for instructions vs. data. The noexec code relies
    on the assumption that the cpu will always use the secondary space
    page table for data accesses while it is running in the secondary
    space mode. Up to the z9-109 class machines this has been the case.
    Unfortunately this is not true anymore with z10 and later machines.
    The load-relative-long instructions lrl, lgrl and lgfrl access the
    memory operand using the same addressing-space mode that has been
    used to fetch the instruction.
    This breaks the noexec mode for all user space binaries compiled
    with march=z10 or later. The only option is to remove the current
    noexec support.
    Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
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