• Oliver O'Halloran's avatar
    selftests/powerpc: Add basic EEH selftest · 85d86c8a
    Oliver O'Halloran authored
    Use the new eeh_dev_check and eeh_dev_break interfaces to test EEH
    recovery.  Historically this has been done manually using platform specific
    EEH error injection facilities (e.g. via RTAS). However, documentation on
    how to use these facilities is haphazard at best and non-existent at worst
    so it's hard to develop a cross-platform test.
    
    The new debugfs interfaces allow the kernel to handle the platform specific
    details so we can write a more generic set of sets. This patch adds the
    most basic of recovery tests where:
    
    a) Errors are injected and recovered from sequentially,
    b) Errors are not injected into PCI-PCI bridges, such as PCIe switches.
    c) Errors are only injected into device function zero.
    d) No errors are injected into Virtual Functions.
    
    a), b) and c) are largely due to limitations of Linux's EEH support.  EEH
    recovery is serialised in the EEH recovery thread which forces a).
    Similarly, multi-function PCI devices are almost always grouped into the
    same PE so injecting an error on one function exercises the same code
    paths. c) is because we currently more or less ignore PCI bridges during
    recovery and assume that the recovered topology will be the same as the
    original.
    
    d) is due to the limits of the eeh_dev_break interface. With the current
    implementation we can't inject an error into a specific VF without
    potentially causing additional errors on other VFs. Due to the serialised
    recovery process we might end up timing out waiting for another function to
    recover before the function of interest is recovered. The platform specific
    error injection facilities are finer-grained and allow this capability, but
    doing that requires working out how to use those facilities first.
    
    Basicly, it's better than nothing and it's a base to build on.
    Signed-off-by: default avatarOliver O'Halloran <oohall@gmail.com>
    Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
    Link: https://lore.kernel.org/r/20190903101605.2890-15-oohall@gmail.com
    85d86c8a
eeh-basic.sh 2 KB