[PATCH V4] powerpc/85xx: Add machine check handler to fix PCIe erratum on mpc85xx

Stuart Yoder b08248 at gmail.com
Tue Mar 5 03:16:10 EST 2013

On Mon, Mar 4, 2013 at 2:40 AM, Jia Hongtao <B38951 at freescale.com> wrote:
> A PCIe erratum of mpc85xx may causes a core hang when a link of PCIe
> goes down. when the link goes down, Non-posted transactions issued
> via the ATMU requiring completion result in an instruction stall.
> At the same time a machine-check exception is generated to the core
> to allow further processing by the handler. We implements the handler
> which skips the instruction caused the stall.

Can you explain at a high level how just skipping an instruction solves
anything?   If you just skip a load/store and continue like nothing is
wrong, isn't your system possibly in a really bad state.

And if the core is already hung, due to the PCI link going down, isn't
it too late?   How does skipping help?


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