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Nick Desaulniers bce5a1e8a3 x86/mem: Move memmove to out of line assembler 
When building ARCH=i386 with CONFIG_LTO_CLANG_FULL=y, it's possible
(depending on additional configs which I have not been able to isolate)
to observe a failure during register allocation:

  error: inline assembly requires more registers than available

when memmove is inlined into tcp_v4_fill_cb() or tcp_v6_fill_cb().

memmove is quite large and probably shouldn't be inlined due to size
alone. A noinline function attribute would be the simplest fix, but
there's a few things that stand out with the current definition:

In addition to having complex constraints that can't always be resolved,
the clobber list seems to be missing %bx. By using numbered operands
rather than symbolic operands, the constraints are quite obnoxious to
refactor.

Having a large function be 99% inline asm is a code smell that this
function should simply be written in stand-alone out-of-line assembler.

Moving this to out of line assembler guarantees that the
compiler cannot inline calls to memmove.

This has been done previously for 64b:
commit 9599ec0471 ("x86-64, mem: Convert memmove() to assembly file
and fix return value bug")

That gives the opportunity for other cleanups like fixing the
inconsistent use of tabs vs spaces and instruction suffixes, and the
label 3 appearing twice.  Symbolic operands, local labels, and
additional comments would provide this code with a fresh coat of paint.

Finally, add a test that tickles the `rep movsl` implementation to test
it for correctness, since it has implicit operands.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Suggested-by: David Laight <David.Laight@aculab.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/all/20221018172155.287409-1-ndesaulniers%40google.com
2022-11-01 15:44:07 -07:00
arch x86/mem: Move memmove to out of line assembler 2022-11-01 15:44:07 -07:00
block block-6.1-2022-10-28 2022-10-29 18:06:52 -07:00
certs certs: make system keyring depend on built-in x509 parser 2022-09-24 04:31:18 +09:00
crypto treewide: use get_random_bytes() when possible 2022-10-11 17:42:58 -06:00
Documentation 23 hotfixes. 2022-10-29 17:49:33 -07:00
drivers fbdev fixes for kernel 6.1-rc3: 2022-10-30 11:31:14 -07:00
fs 3 cifs/smb3 fixes (also for stable) 2022-10-30 09:40:04 -07:00
include fbdev fixes for kernel 6.1-rc3: 2022-10-30 11:31:14 -07:00
init init: Kconfig: fix spelling mistake "satify" -> "satisfy" 2022-10-20 21:27:22 -07:00
io_uring io_uring: unlock if __io_run_local_work locked inside 2022-10-27 09:52:12 -06:00
ipc ipc/msg.c: fix percpu_counter use after free 2022-10-28 13:37:22 -07:00
kernel - Rename a perf memory level event define to denote it is of CXL type 2022-10-30 09:49:18 -07:00
lib x86/mem: Move memmove to out of line assembler 2022-11-01 15:44:07 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mmap: fix remap_file_pages() regression 2022-10-28 13:37:23 -07:00
net kcm: do not sense pfmemalloc status in kcm_sendpage() 2022-10-27 11:25:13 -07:00
rust Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
samples VFIO updates for v6.1-rc1 2022-10-12 14:46:48 -07:00
scripts Kbuild fixes for v6.1 2022-10-16 11:12:22 -07:00
security selinux: enable use of both GFP_KERNEL and GFP_ATOMIC in convert_context() 2022-10-19 09:55:53 -04:00
sound ALSA: aoa: Fix I2S device accounting 2022-10-27 08:53:08 +02:00
tools Char/Misc fixes for 6.1-rc3 2022-10-30 11:22:33 -07:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt kvm: Add support for arch compat vm ioctls 2022-10-22 05:15:23 -04:00
.clang-format PCI/DOE: Add DOE mailbox support functions 2022-07-19 15:38:04 -07:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap mailmap: update email for Qais Yousef 2022-10-20 21:27:21 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS drm for 5.20/6.0 2022-08-03 19:52:08 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS USB fixes for 6.1-rc3 2022-10-30 10:35:07 -07:00
Makefile Linux 6.1-rc3 2022-10-30 15:19:28 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

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.