84e599e3ad
The kernel starts with machine checks disabled (machine check mask bit in the PSW is zero), and machine checks are enabled when trap_init() is called. The rationale is that this allows to assume that the system is initialized up to a certain point before the machine check handler may be invoked. However the implementation is incomplete: all new PSW masks in lowcore have the machine check mask bit. This means that e.g. for any early program check machine checks are enabled within the program check handler. This contradicts the whole point of enabling machine checks at a single place. Change this and initialize all new PSWs in lowcore so they have the machine check mask bit not set. Set the bit in all masks in trap_init(). This way machine check enabling is consistent. Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.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.