[C/R ARM][PATCH 3/3] c/r: ARM implementation of checkpoint/restart
From: Jamie Lokier <hidden>
Date: 2010-03-26 02:48:15
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Christoffer Dall wrote:
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That doesn't indicate what ISA version the system is running on, or even if the ABI is compatible (we have two ABIs - OABI and EABI).That's why I checkpointed CONFIG_OABI_COMPAT, but I realize that it's not sufficient. How about checkpointing CONFIG_AEABI and CONFIG_OABI_COMPAT and making sure that we either restore to the same setting of the two or restore to CONFIG_OABI_COMPAT=y?
With CONFIG_OABI_COMPAT enabled, each process can be in either personality: OABI or EABI. Checkpointing will need to remember which one. With CONFIG_OABI_COMPAT disabled, it'll be fixed at one or the other, but there's no reason why a process should not be moved between kernels with different values of CONFIG_OABI_COMPAT, so long as the OABI or EABI personality is supported by the destination kernel. In other words, CONFIG_OABI_COMPAT shouldn't be in the checkpoint state at all - only the per-process personalities should be.
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We checkpoint whether the system is running with CONFIG_MMU or not and require the same configuration for the system on which we restore the process. It might be possible to allow something more fine-grained, if it's worth the energy. Input on this item is also very welcome, specifically from someone who knows the exact meaning of the end_brk field.Processes which run on MMU and non-MMU CPUs are unlikely to be interchangable - the run time environments are quite different. ?I think this is a sane check.thanks.
It's possible in principle to run many non-MMU binaries on MMU kernels, but I've never heard of anyone doing it. -- Jamie