c5e2edeb01
GCC 8.1.0 reports that the ldadd instruction encoding, recently added to
insn.c, doesn't match the mask and couldn't possibly be identified:
linux/arch/arm64/include/asm/insn.h: In function 'aarch64_insn_is_ldadd':
linux/arch/arm64/include/asm/insn.h:280:257: warning: bitwise comparison always evaluates to false [-Wtautological-compare]
Bits [31:30] normally encode the size of the instruction (1 to 8 bytes)
and the current instruction value only encodes the 4- and 8-byte
variants. At the moment only the BPF JIT needs this instruction, and
doesn't require the 1- and 2-byte variants, but to be consistent with
our other ldr and str instruction encodings, clear the size field in the
insn value.
Fixes: 34b8ab091f ("bpf, arm64: use more scalable stadd over ldxr / stxr loop in xadd")
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Reported-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.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.