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Tony Ambardar 0a5d3258d7 compiler_types.h: Define __retain for __attribute__((__retain__))
Some code includes the __used macro to prevent functions and data from
being optimized out. This macro implements __attribute__((__used__)),
which operates at the compiler and IR-level, and so still allows a linker
to remove objects intended to be kept.

Compilers supporting __attribute__((__retain__)) can address this gap by
setting the flag SHF_GNU_RETAIN on the section of a function/variable,
indicating to the linker the object should be retained. This attribute is
available since gcc 11, clang 13, and binutils 2.36.

Provide a __retain macro implementing __attribute__((__retain__)), whose
first user will be the '__bpf_kfunc' tag.

[ Additional remark from discussion:

  Why is CONFIG_LTO_CLANG added here? The __used macro permits garbage
  collection at section level, so CLANG_LTO_CLANG without
  CONFIG_LD_DEAD_CODE_DATA_ELIMINATION should not change final section
  dynamics?

  The conditional guard was included to ensure consistent behaviour
  between __retain and other features forcing split sections. In
  particular, the same guard is used in vmlinux.lds.h to merge split
  sections where needed. For example, using __retain in LLVM builds
  without CONFIG_LTO was failing CI tests on kernel-patches/bpf because
  the kernel didn't boot properly. And in further testing, the kernel
  had no issues loading BPF kfunc modules with such split sections, so
  the module (partial) linking scripts were left alone. ]

Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/ZlmGoT9KiYLZd91S@krava/T/
Link: https://lore.kernel.org/bpf/b31bca5a5e6765a0f32cc8c19b1d9cdbfaa822b5.1717477560.git.Tony.Ambardar@gmail.com
2024-06-14 19:08:32 +02:00
arch ARM: 2024-06-05 08:43:41 -07:00
block blk-throttle: Fix incorrect display of io.max 2024-05-30 19:44:29 -06:00
certs kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
crypto This push fixes a bug in the new ecc P521 code as well as a buggy 2024-05-20 08:47:54 -07:00
Documentation Including fixes from BPF and big collection of fixes for WiFi core 2024-06-06 09:55:27 -07:00
drivers net: stmmac: replace priv->speed with the portTransmitRate from the tc-cbs parameters 2024-06-11 19:58:18 -07:00
fs for-6.10-rc2-tag 2024-06-05 11:28:25 -07:00
include compiler_types.h: Define __retain for __attribute__((__retain__)) 2024-06-14 19:08:32 +02:00
init Driver core changes for 6.10-rc1 2024-05-22 12:13:40 -07:00
io_uring io_uring/net: assign kmsg inq/flags before buffer selection 2024-05-30 14:04:37 -06:00
ipc Mainly singleton patches, documented in their respective changelogs. 2024-05-19 14:02:03 -07:00
kernel bpf: fix UML x86_64 compile failure 2024-06-13 11:24:45 -07:00
lib Including fixes from BPF and big collection of fixes for WiFi core 2024-06-06 09:55:27 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm 16 hotfixes, 11 of which are cc:stable. 2024-05-25 15:10:33 -07:00
net bpf: Avoid splat in pskb_pull_reason 2024-06-14 17:20:21 +02:00
rust LoongArch changes for v6.10 2024-05-22 09:43:07 -07:00
samples tracing/treewide: Remove second parameter of __assign_str() 2024-05-22 20:14:47 -04:00
scripts dt-bindings: kbuild: Fix dt_binding_check on unconfigured build 2024-05-30 01:15:58 +09:00
security tomoyo: update project links 2024-06-03 22:43:11 +09:00
sound ALSA: seq: ump: Fix swapped song position pointer data 2024-05-31 09:51:44 +02:00
tools selftests/bpf: Add test coverage for reg_set_min_max handling 2024-06-13 11:16:01 -07:00
usr kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
virt The usual shower of singleton fixes and minor series all over MM, 2024-05-19 09:21:03 -07:00
.clang-format clang-format: Update with v6.7-rc4's for_each macro list 2023-12-08 23:54:38 +01:00
.cocciconfig
.editorconfig Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: create a list of all built DTB files 2024-02-19 18:20:39 +09:00
.mailmap MAINTAINERS: mailmap: Update Stanislav's email address 2024-06-12 17:58:36 -07:00
.rustfmt.toml
COPYING
CREDITS MAINTAINERS: Drop Gustavo Pimentel as PCI DWC Maintainer 2024-03-27 13:41:02 -05:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig
MAINTAINERS MAINTAINERS: mailmap: Update Stanislav's email address 2024-06-12 17:58:36 -07:00
Makefile Linux 6.10-rc2 2024-06-02 15:44:56 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -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 reStructuredText 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.