fb46d057db
- Add support for zstd compressed kernel - Define __DISABLE_EXPORTS in Makefile - Remove __DISABLE_EXPORTS definition from kaslr.c - Bump the heap size for zstd. - Update the documentation. Integrates the ZSTD decompression code to the x86 pre-boot code. Zstandard requires slightly more memory during the kernel decompression on x86 (192 KB vs 64 KB), and the memory usage is independent of the window size. __DISABLE_EXPORTS is now defined in the Makefile, which covers both the existing use in kaslr.c, and the use needed by the zstd decompressor in misc.c. This patch has been boot tested with both a zstd and gzip compressed kernel on i386 and x86_64 using buildroot and QEMU. Additionally, this has been tested in production on x86_64 devices. We saw a 2 second boot time reduction by switching kernel compression from xz to zstd. Signed-off-by: Nick Terrell <terrelln@fb.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200730190841.2071656-7-nickrterrell@gmail.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.