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.
Mark Rutland
authored
[ Upstream commit 3eefdf9d ] The branch range checks in ftrace_make_call() and ftrace_make_nop() are incorrect, erroneously permitting a forwards branch of 128M and erroneously rejecting a backwards branch of 128M. This is because both functions calculate the offset backwards, calculating the offset *from* the target *to* the branch, rather than the other way around as the later comparisons expect. If an out-of-range branch were erroeously permitted, this would later be rejected by aarch64_insn_gen_branch_imm() as branch_imm_common() checks the bounds correctly, resulting in warnings and the placement of a BRK instruction. Note that this can only happen for a forwards branch of exactly 128M, and so the caller would need to be exactly 128M bytes below the relevant ftrace trampoline. If an in-range branch were erroeously rejected, then: * For modules when CONFIG_ARM64_MODULE_PLTS=y, this would result in the use of a PLT entry, whi...