030d374eb9
The arm64 module region is a 128 MB region that is kept close to the core kernel, in order to ensure that relative branches are always in range. So using the same region for programs that do not have this restriction is wasteful, and preferably avoided. Now that the core BPF JIT code permits the alloc/free routines to be overridden, implement them by vmalloc()/vfree() calls from a dedicated 128 MB region set aside for BPF programs. This ensures that BPF programs are still in branching range of each other, which is something the JIT currently depends upon (and is not guaranteed when using module_alloc() on KASLR kernels like we do currently). It also ensures that placement of BPF programs does not correlate with the placement of the core kernel or modules, making it less likely that leaking the former will reveal the latter. This also solves an issue under KASAN, where shadow memory is needlessly allocated for all BPF programs (which don't require KASAN shadow pages since they are not KASAN instrumented) Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Danny Lin <danny@kdrag0n.dev> Change-Id: Id3a066651f282249e8825b7bcdf9a78e84c1f878
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.