• Becky Bruce's avatar
    [POWERPC] Avoid unpaired stwcx. on some processors · b64f87c1
    Becky Bruce authored
    The context switch code in the kernel issues a dummy stwcx. to clear the
    reservation, as recommended by the architecture.  However, some processors
    can have issues if this stwcx to address A occurs while the reservation
    is already held to a different address B.  To avoid this problem, the dummy
    stwcx. needs to be paired with a dummy lwarx to the same address.
    
    This adds the dummy lwarx, and creates a cpu feature bit to indicate
    which cpus are affected.  Tested on mpc8641_hpcn_defconfig in
    arch/powerpc; build tested in arch/ppc.
    Signed-off-by: default avatarBecky Bruce <becky.bruce@freescale.com>
    Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    b64f87c1
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