472de63b0b
The SDEI handler save/restores the addr_limit using set_fs(). It isn't very clear why. The reason is to mirror the arch code's entry assembly. The arch code does this because perf may access user-space, and inheriting the addr_limit may be a problem. Add a comment explaining why this is here. Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: James Morse <james.morse@arm.com> Link: https://bugs.chromium.org/p/project-zero/issues/detail?id=822 Link: https://lore.kernel.org/r/20200519182108.13693-4-james.morse@arm.com Signed-off-by: Will Deacon <will@kernel.org>
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.