970d54f99c
With STRICT_KERNEL_RWX on in a relocatable kernel under the hash MMU, if the position the kernel is loaded at is not 16M aligned things go horribly wrong. Specifically hash__mark_initmem_nx() will call hash__change_memory_range() which then aligns down the start address, and due to the text not being 16M aligned causes some of the kernel text to be marked non-executable. We can avoid this when selecting the linear mapping size, so do so and print a warning. I tested this for various alignments and as long as the position is 64K aligned it's fine (the base requirement for powerpc). Signed-off-by: Russell Currey <ruscur@russell.cc> [mpe: Add details of the failure mode] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20191224064126.183670-1-ruscur@russell.cc
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.