40530db7c6
[text mostly copied from benh's RFC/WIP] ppc32 are still doing something rather gothic and wrong on 32-bit which we stopped doing on 64-bit a while ago. We have that thing where some handlers "copy" the EE value from the original stack frame into the new MSR before transferring to the handler. Thus for a number of exceptions, we enter the handlers with interrupts enabled. This is rather fishy, some of the stuff that handlers might do early on such as irq_enter/exit or user_exit, context tracking, etc... should be run with interrupts off afaik. Generally our handlers know when to re-enable interrupts if needed. The problem we were having is that we assumed these interrupts would return with interrupts enabled. However that isn't the case. Instead, this patch changes things so that we always enter exception handlers with interrupts *off* with the notable exception of syscalls which are special (and get a fast path). Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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.