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Arnaldo Carvalho de Melo 1768d3a014 perf build: Disable BPF skeletons if clang version is < 12.0.1
While building on a wide range of distros and clang versions it was
noticed that at least version 12.0.1 (noticed on Alpine 3.15 with
"Alpine clang version 12.0.1") is needed to not fail with BTF generation
errors such as:

Debian:10

  Debian clang version 11.0.1-2~deb10u1:

    CLANG   /tmp/build/perf/util/bpf_skel/.tmp/sample_filter.bpf.o
  <SNIP>
    GENSKEL /tmp/build/perf/util/bpf_skel/sample_filter.skel.h
  libbpf: failed to find BTF for extern 'bpf_cast_to_kern_ctx' [21] section: -2
  Error: failed to open BPF object file: No such file or directory
  make[2]: *** [Makefile.perf:1121: /tmp/build/perf/util/bpf_skel/sample_filter.skel.h] Error 254
  make[2]: *** Deleting file '/tmp/build/perf/util/bpf_skel/sample_filter.skel.h'

Amazon Linux 2:

  clang version 11.1.0 (Amazon Linux 2 11.1.0-1.amzn2.0.2)

    GENSKEL /tmp/build/perf/util/bpf_skel/sample_filter.skel.h
  libbpf: elf: skipping unrecognized data section(18) .eh_frame
  libbpf: elf: skipping relo section(19) .rel.eh_frame for section(18) .eh_frame
  libbpf: failed to find BTF for extern 'bpf_cast_to_kern_ctx' [21] section: -2
  Error: failed to open BPF object file: No such file or directory
  make[2]: *** [/tmp/build/perf/util/bpf_skel/sample_filter.skel.h] Error 254
  make[2]: *** Deleting file `/tmp/build/perf/util/bpf_skel/sample_filter.skel.h'

Ubuntu 20.04:

  clang version 10.0.0-4ubuntu1

    CLANG   /tmp/build/perf/util/bpf_skel/.tmp/augmented_raw_syscalls.bpf.o
    GENSKEL /tmp/build/perf/util/bpf_skel/bench_uprobe.skel.h
    GENSKEL /tmp/build/perf/util/bpf_skel/bperf_leader.skel.h
  libbpf: sec '.reluprobe': corrupted symbol #27 pointing to invalid section #65522 for relo #0
    GENSKEL /tmp/build/perf/util/bpf_skel/bperf_follower.skel.h
  Error: failed to open BPF object file: BPF object format invalid
  make[2]: *** [Makefile.perf:1121: /tmp/build/perf/util/bpf_skel/bench_uprobe.skel.h] Error 95
  make[2]: *** Deleting file '/tmp/build/perf/util/bpf_skel/bench_uprobe.skel.h'

So check if the version is at least 12.0.1 otherwise disable building
BPF skels and provide a message about it, continuing the build.

The message, when running on amazonlinux:2:

  Makefile.config:698: Warning: Disabled BPF skeletons as reliable BTF generation needs at least clang version 12.0.1

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/ZTvGx/Ou6BVnYBqi@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
2023-10-27 19:27:33 -07:00
arch Fix preemption delays in the SGX code, remove unnecessarily UAPI-exported code, 2023-09-10 10:39:31 -07:00
block block: fix pin count management when merging same-page segments 2023-09-06 07:32:27 -06:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto This update includes the following changes: 2023-08-29 11:23:29 -07:00
Documentation drm ci for 6.6-rc1 2023-09-10 11:55:26 -07:00
drivers drm ci for 6.6-rc1 2023-09-10 11:55:26 -07:00
fs six smb3 client fixes, one fix for nls Kconfig, one minor spnego registry update 2023-09-09 19:56:23 -07:00
include six smb3 client fixes, one fix for nls Kconfig, one minor spnego registry update 2023-09-09 19:56:23 -07:00
init workqueue: Changes for v6.6 2023-09-01 16:06:32 -07:00
io_uring Revert "io_uring: fix IO hang in io_wq_put_and_exit from do_exit()" 2023-09-07 09:41:49 -06:00
ipc Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
kernel RISC-V Patches for the 6.6 Merge Window, Part 2 (try 2) 2023-09-09 14:25:11 -07:00
lib iov_iter: Kunit tests for page extraction 2023-09-09 15:11:49 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm LoongArch changes for v6.6 2023-09-08 12:16:52 -07:00
net Including fixes from netfilter and bpf. 2023-09-07 18:33:07 -07:00
rust Documentation work keeps chugging along; stuff for 6.6 includes: 2023-08-30 20:05:42 -07:00
samples VFIO updates for v6.6-rc1 2023-08-30 20:36:01 -07:00
scripts run-clang-tools: Add pass through checks and and header-filter arguments 2023-10-12 10:01:55 -07:00
security Landlock updates for v6.6-rc1 2023-09-08 12:06:51 -07:00
sound sound fixes for 6.6-rc1 2023-09-08 13:07:50 -07:00
tools perf build: Disable BPF skeletons if clang version is < 12.0.1 2023-10-27 19:27:33 -07:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt ARM: 2023-09-07 13:52:20 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: rename binkernel.spec to kernel.spec 2023-07-25 00:59:33 +09:00
.mailmap for-linus-2023083101 2023-09-01 12:31:44 -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 USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
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 drm ci for 6.6-rc1 2023-09-10 11:55:26 -07:00
Makefile Linux 6.6-rc1 2023-09-10 16:28:41 -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.