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Nathan Chancellor 8cdd23c23c arm64: Restrict ARM64_BTI_KERNEL to clang 12.0.0 and newer
Commit 97fed779f2 ("arm64: bti: Provide Kconfig for kernel mode BTI")
disabled CONFIG_ARM64_BTI_KERNEL when CONFIG_GCOV_KERNEL was enabled and
compiling with clang because of warnings that were seen with
allmodconfig because LLVM was not emitting PAC/BTI instructions for
compiler generated functions:

  | warning: some functions compiled with BTI and some compiled without BTI
  | warning: not setting BTI in feature flags

This dependency was fine for avoiding the warnings with allmodconfig
until commit 51c2ee6d12 ("Kconfig: Introduce ARCH_WANTS_NO_INSTR and
CC_HAS_NO_PROFILE_FN_ATTR"), which prevents CONFIG_GCOV_KERNEL from
being enabled with clang 12.0.0 or older because those versions do not
support the no_profile_instrument_function attribute.

As a result, CONFIG_ARM64_BTI_KERNEL gets enabled with allmodconfig and
there are more warnings like the ones above due to CONFIG_KASAN, which
suffers from the same problem as CONFIG_GCOV_KERNEL. This was most
likely not noticed at the time because allmodconfig +
CONFIG_GCOV_KERNEL=n was not tested. defconfig + CONFIG_KASAN=y is
enough to reproduce the same warnings as above.

The root cause of the warnings was resolved in LLVM during the 12.0.0
release so rather than play whack-a-mole with the dependencies, just
update CONFIG_ARM64_BTI_KERNEL to require clang 12.0.0, which will have
all of the issues ironed out.

Link: https://github.com/ClangBuiltLinux/linux/issues/1428
Link: https://github.com/ClangBuiltLinux/continuous-integration2/runs/3010034706?check_suite_focus=true
Link: https://github.com/ClangBuiltLinux/continuous-integration2/runs/3010035725?check_suite_focus=true
Link: a88c722e68
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20210712214636.3134425-1-nathan@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
2021-07-13 16:31:31 +01:00
arch arm64: Restrict ARM64_BTI_KERNEL to clang 12.0.0 and newer 2021-07-13 16:31:31 +01:00
block block-5.14-2021-07-08 2021-07-09 12:05:33 -07:00
certs Kbuild updates for v5.13 (2nd) 2021-05-08 10:00:11 -07:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2021-07-09 11:00:44 -07:00
Documentation RTC for 5.14 2021-07-10 16:19:10 -07:00
drivers Two fixes: 2021-07-11 11:17:57 -07:00
fs 13 cifs/smb3 fixes. Most are to address minor issues pointed out by Coverity. Also includes a packet signing enhancement and mount improvement 2021-07-10 12:04:58 -07:00
include Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
init Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
ipc Merge branch 'akpm' (patches from Andrew) 2021-07-02 12:08:10 -07:00
kernel Two fixes: 2021-07-11 11:17:57 -07:00
lib mm/page_alloc: Revert pahole zero-sized workaround 2021-07-10 16:09:39 -07:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
mm mm/rmap: try_to_migrate() skip zone_device !device_private 2021-07-11 15:05:15 -07:00
net We have new filesystem client metrics for reporting I/O sizes from 2021-07-09 09:52:13 -07:00
samples VFIO update for v5.14-rc1 2021-07-03 11:49:33 -07:00
scripts Kbuild updates for v5.14 2021-07-10 11:01:38 -07:00
security asm-generic/unaligned: Unify asm/unaligned.h around struct helper 2021-07-02 12:43:40 -07:00
sound sound fixes for 5.14-rc1 2021-07-09 11:40:26 -07:00
tools perf tools changes for v5.14: 2nd batch 2021-07-11 10:54:24 -07:00
usr .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
virt Merge branch 'akpm' (patches from Andrew) 2021-06-29 17:29:11 -07:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap m68k updates for v5.14 2021-06-28 14:01:03 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: move Murali Karicheri to credits 2021-04-29 15:47:30 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS SCSI misc on 20210711 2021-07-11 10:59:53 -07:00
Makefile Linux 5.14-rc1 2021-07-11 15:07:40 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.