e2aa34ce80
The panic notifiers infrastructure is a bit limited in the scope of the callbacks - basically every kind of functionality is dropped in a list that runs in the same point during the kernel panic path. This is not really on par with the complexities and particularities of architecture / hypervisors' needs, and a refactor is ongoing. As part of this refactor, it was observed that powerpc has 2 notifiers, with mixed goals: one is just a KASLR offset dumper, whereas the other aims to hard-disable IRQs (necessary on panic path), warn firmware of the panic event (fadump) and run low-level platform-specific machinery that might stop kernel execution and never come back. Clearly, the 2nd notifier has opposed goals: disable IRQs / fadump should run earlier while low-level platform actions should run late since it might not even return. Hence, this patch decouples the notifiers splitting them in three: - First one is responsible for hard-disable IRQs and fadump, should run early; - The kernel KASLR offset dumper is really an informative notifier, harmless and may run at any moment in the panic path; - The last notifier should run last, since it aims to perform low-level actions for specific platforms, and might never return. It is also only registered for 2 platforms, pseries and ps3. The patch better documents the notifiers and clears the code too, also removing a useless header. Currently no functionality change should be observed, but after the planned panic refactor we should expect more panic reliability with this patch. Signed-off-by: Guilherme G. Piccoli <gpiccoli@igalia.com> Reviewed-by: Hari Bathini <hbathini@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220427224924.592546-9-gpiccoli@igalia.com
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
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.