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    powerpc/pseries: Introduce api_version to migration sysfs interface · 288a298c
    Tyrel Datwyler 提交于
    The /sys/kernel/mobility/migration interface was added all the way back
    in 2.6.37. However, the drmgr userspace tool was never augmented to use
    this interface to perfrom migrations. Instead it has continued using a
    faux rtas call coupled with performing the device tree update processing
    in userspace and communicating it back to the kernel via the ugly
    /proc/ppc64/ofdt interface.
    
    Up until 3.12 the device tree update code in the kernel was badly broken
    and bit rotting. This code was fixed in 3.12 and is now utilized by the
    kernel suspend code as of 3.15. The kernel is now better suited to
    handle the post-mobility fixup of the device tree and drmgr should be
    transitioned to using the sysfs migration interface.
    
    This patch introduces the api_version sysfs file to /sys/kernel/mobility
    as a means for drmgr to query the current implementation level of the
    kernel migration code. This initial versioning indicates it is capable
    of perfroming all current PAPR requirements for migration including the
    post-mobility firmware activation and device tree update.
    Signed-off-by: NTyrel Datwyler <tyreld@linux.vnet.ibm.com>
    Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
    Cc: Cyril Bur <cyrilbur@gmail.com>
    Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
    288a298c
mobility.c 7.9 KB