f637fbc7bd
[ Upstream commit 4b5305decc8436bfe363d1c1773e8fa1c828b14d ] In order to remove further .fixup usage, extend the extable infrastructure to take additional information from the extable entry sites. Specifically add _ASM_EXTABLE_TYPE_REG() and EX_TYPE_IMM_REG that extend the existing _ASM_EXTABLE_TYPE() by taking an additional register argument and encoding that and an s16 immediate into the existing s32 type field. This limits the actual types to the first byte, 255 seem plenty. Also add a few flags into the type word, specifically CLEAR_AX and CLEAR_DX which clear the return and extended return register. Notes: - due to the % in our register names it's hard to make it more generally usable as arm64 did. - the s16 is far larger than used in these patches, future extentions can easily shrink this to get more bits. - without the bitfield fix this will not compile, because: 0xFF > -1 and we can't even extract the TYPE field. [nathanchance: Build fix for clang-lto builds: https://lkml.kernel.org/r/20211210234953.3420108-1-nathan@kernel.org ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lore.kernel.org/r/20211110101325.303890153@infradead.org Signed-off-by: Sasha Levin <sashal@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.