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Unrecovered MCE and HMI errors are sent through a special restart OPAL call to log the platform error. The downside is that they don't go through normal Linux crash paths, so they don't give much information to the Linux console. Change this by providing a special crash function which does some of the console flushing from the panic() path before calling firmware to reboot. The downside of this is a little more code to execute before reaching the firmware reboot. However in practice, it's critical to get the Linux console messages output in order to debug a problem. So this is a desirable tradeoff. Note on the implementation: It is difficult to plumb a custom reboot handler into the panic path, because panic does a little bit too much work. For example, it will try to delay with the timebase, but that may be corrupted in some cases resulting in a hang without reaching the platform reboot. Another problem is that panic can invoke the crash dump code which is not what we want in the case of a hardware platform error. Long-term the best solution will be to rework the panic path so it can be suitable for this kind of panic, but for now we just duplicate a bit of the code. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.