Andrii Nakryiko
40df54cf02
BACKPORT: btf: expose BTF info through sysfs ...
Make .BTF section allocated and expose its contents through sysfs.
/sys/kernel/btf directory is created to contain all the BTFs present
inside kernel. Currently there is only kernel's main BTF, represented as
/sys/kernel/btf/kernel file. Once kernel modules' BTFs are supported,
each module will expose its BTF as /sys/kernel/btf/<module-name> file.
Current approach relies on a few pieces coming together:
1. pahole is used to take almost final vmlinux image (modulo .BTF and
kallsyms) and generate .BTF section by converting DWARF info into
BTF. This section is not allocated and not mapped to any segment,
though, so is not yet accessible from inside kernel at runtime.
2. objcopy dumps .BTF contents into binary file and subsequently
convert binary file into linkable object file with automatically
generated symbols _binary__btf_kernel_bin_start and
_binary__btf_kernel_bin_end, pointing to start and end, respectively,
of BTF raw data.
3. final vmlinux image is generated by linking this object file (and
kallsyms, if necessary). sysfs_btf.c then creates
/sys/kernel/btf/kernel file and exposes embedded BTF contents through
it. This allows, e.g., libbpf and bpftool access BTF info at
well-known location, without resorting to searching for vmlinux image
on disk (location of which is not standardized and vmlinux image
might not be even available in some scenarios, e.g., inside qemu
during testing).
Alternative approach using .incbin assembler directive to embed BTF
contents directly was attempted but didn't work, because sysfs_proc.o is
not re-compiled during link-vmlinux.sh stage. This is required, though,
to update embedded BTF data (initially empty data is embedded, then
pahole generates BTF info and we need to regenerate sysfs_btf.o with
updated contents, but it's too late at that point).
If BTF couldn't be generated due to missing or too old pahole,
sysfs_btf.c handles that gracefully by detecting that
_binary__btf_kernel_bin_start (weak symbol) is 0 and not creating
/sys/kernel/btf at all.
v2->v3:
- added Documentation/ABI/testing/sysfs-kernel-btf (Greg K-H);
- created proper kobject (btf_kobj) for btf directory (Greg K-H);
- undo v2 change of reusing vmlinux, as it causes extra kallsyms pass
due to initially missing __binary__btf_kernel_bin_{start/end} symbols;
v1->v2:
- allow kallsyms stage to re-use vmlinux generated by gen_btf();
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Change-Id: Ife57356dd14b9ae0d2e3801eea7c602c6245952f
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sorayukii <sorayukii69@gmail.com>
2026-05-15 17:58:05 +07:00
fixdep: faster CONFIG_ search
2016-08-24 22:34:19 +02:00
fs: stream_open - opener for stream-like files so that read and write can run simultaneously without deadlock
2019-06-11 12:22:49 +02:00
Merge remote-tracking branch 'common/android-4.9-q' into android12-4.9-sdm845
2022-03-31 22:52:51 +03:00
gcc-plugins: latent_entropy: use /dev/urandom
2022-04-20 09:06:46 +02:00
scripts/gdb: fix lx-version string output
2021-01-12 19:49:03 +01:00
kbuild: Regenerate genksyms lexer
2016-08-25 20:03:51 +02:00
kconfig/lxdialog: Make main() return 0
2024-10-09 17:15:11 +03:00
This is the 4.9.321 stable release
2022-07-03 10:09:05 +02:00
builddeb: Fix header package regarding dtc source links
2018-05-30 07:50:39 +02:00
selinux: use "grep -E" instead of "egrep"
2022-10-26 13:15:38 +02:00
scripts/tracing: fix the bug that can't parse raw_trace_func
2021-08-15 13:01:03 +02:00
kbuild: make scripts/adjust_autoksyms.sh robust against timestamp races
2018-05-30 07:50:37 +02:00
tweewide: Fix most Shebang lines
2021-06-03 08:23:27 +02:00
ASN.1: fix open failure check on headername
2016-04-06 14:06:48 +01:00
scripts: switch explicitly to Python 3
2021-06-03 08:23:27 +02:00
tweewide: Fix most Shebang lines
2021-06-03 08:23:27 +02:00
BACKPORT: bpf: add script and prepare bpf.h for new helpers documentation
2026-05-15 17:56:21 +07:00
scripts: build-all.py: set clang as REAL_CC for arm
2020-02-27 21:25:17 -08:00
scripts: snapshot of kernel build utility scripts
2016-08-08 15:22:37 -07:00
scripts: snapshot of kernel build utility scripts
2016-08-08 15:22:37 -07:00
scripts: snapshot of kernel build utility scripts
2016-08-08 15:22:37 -07:00
tweewide: Fix most Shebang lines
2021-06-03 08:23:27 +02:00
checkkconfigsymbols: use arglist instead of cmd string
2016-08-28 11:08:34 +02:00
Merge tag 'LA.UM.10.3.r1-01000-sdm845.0' of https://source.codeaurora.org/quic/la/kernel/msm-4.9 into android12-4.9-sdm845
2022-03-31 20:16:10 +03:00
tweewide: Fix most Shebang lines
2021-06-03 08:23:27 +02:00
ANDROID: Kbuild, LLVMLinux: allow overriding clang target triple
2018-11-28 17:35:40 -08:00
FROMLIST: kbuild: add clang-version.sh
2018-02-28 15:09:57 -08:00
coccinelle: fix parallel build with CHECK=scripts/coccicheck
2017-12-14 09:28:22 +01:00
tweewide: Fix most Shebang lines
2021-06-03 08:23:27 +02:00
const_structs.checkpatch: remove drm_connector from the list
2018-02-04 21:39:49 -08:00
scripts/decode_stacktrace: strip basepath from all paths
2020-07-31 16:44:03 +02:00
scripts/decodecode: fix trapping instruction formatting
2020-05-20 08:15:29 +02:00
depmod: handle the case of /sbin/depmod without /sbin in PATH
2021-01-12 19:49:01 +01:00
scripts: switch explicitly to Python 3
2021-06-03 08:23:27 +02:00
docproc: print a comment about autogeneration for rst output
2016-05-14 09:56:56 -06:00
cert host tools: Stop complaining about deprecated OpenSSL functions
2022-11-25 17:35:37 +01:00
tweewide: Fix most Shebang lines
2021-06-03 08:23:27 +02:00
scripts/faddr2line: improve on base path filtering a bit
2016-09-19 14:49:08 -07:00
gcc-plugins: abort builds cleanly when not supported
2016-08-08 17:49:05 -07:00
scripts/has-stack-protector: add -fno-PIE
2016-11-09 22:28:05 +01:00
initramfs: Escape colons in depfile
2016-09-23 10:35:32 +02:00
tweewide: Fix most Shebang lines
2021-06-03 08:23:27 +02:00
get_maintainer: quiet noisy implicit -f vcs_file_exists checking
2016-08-26 17:39:34 -07:00
headers_check: don't warn about c++ guards
2016-05-24 14:12:48 +10:00
scripts/kallsyms: remove redundant is_arm_mapping_symbol()
2026-05-15 17:48:21 +07:00
arm64: build with baremetal linker target instead of Linux when available
2022-10-13 01:53:43 +03:00
scripts/kernel-doc: Don't fail with status != 0 if error encountered with -none
2018-02-25 11:05:47 +01:00
ld-version: Drop the 4th and 5th version components
2016-05-13 14:02:05 +02:00
BACKPORT: btf: expose BTF info through sysfs
2026-05-15 17:58:05 +07:00
scripts: set proper OpenSSL include dir also for sign-file
2021-03-07 11:25:55 +01:00
kbuild: replace genhdr-y with generated-y
2020-04-09 15:53:27 +05:30
Merge branch 'android-4.9-q' of https://android.googlesource.com/kernel/common into lineage-18.1-caf-sdm845
2021-04-26 01:27:02 +03:00
ANDROID: kbuild: Makefile.clean: make Kbuild and Makefile optional
2017-01-27 13:52:26 -08:00
scripts: Makefile: Add multi overlay dtbo-base apply verify
2017-11-24 16:56:41 +08:00
Makefile.extrawarn: Move -Wcast-function-type-strict to W=1
2022-10-26 13:15:33 +02:00
gcc-plugins: Add latent_entropy plugin
2016-10-10 14:51:44 -07:00
kbuild: skip install/check of headers right under uapi directories
2020-04-09 16:19:34 +05:30
kbuild: use HOSTLDFLAGS for single .c executables
2022-10-13 01:53:40 +03:00
This is the 4.9.121 stable release
2018-08-17 21:31:08 +02:00
dtc: Silence warnings
2022-10-13 01:53:45 +03:00
ANDROID: kbuild: make it possible to specify the module output dir
2017-01-27 13:52:26 -08:00
This is the 4.9.327 stable release
2022-09-05 14:02:59 +02:00
Kbuild: enable -Wmaybe-uninitialized warning for "make W=1"
2016-11-11 08:45:08 -08:00
tweewide: Fix most Shebang lines
2021-06-03 08:23:27 +02:00
scripts: Support a custom compiler name
2026-05-15 17:48:21 +07:00
mksysmap: Fix the mismatch of '.L' symbols in System.map
2020-06-30 15:38:23 -04:00
objtool, modules: Discard objtool annotation sections for modules
2018-01-17 09:38:58 +01:00
namespace: fix namespace.pl script to support relative paths
2019-10-29 09:15:06 +01:00
tweewide: Fix most Shebang lines
2021-06-03 08:23:27 +02:00
This is the 4.9.262 stable release
2021-03-17 17:12:54 +01:00
recordmcount: Fix spurious mcount entries on powerpc
2019-08-04 09:33:38 +02:00
recordmcount.pl: fix typo in s390 mcount regex
2022-01-05 12:31:24 +01:00
script: Do not append a plus behind the localversion
2026-05-15 17:48:21 +07:00
tweewide: Fix most Shebang lines
2021-06-03 08:23:27 +02:00
cert host tools: Stop complaining about deprecated OpenSSL functions
2022-11-25 17:35:37 +01:00
parisc: Use generic extable search and sort routines
2016-03-23 16:00:46 +01:00
spelling.txt: "modeled" is spelt correctly
2016-10-07 18:46:30 -07:00
tweewide: Fix most Shebang lines
2021-06-03 08:23:27 +02:00
BACKPORT: mm: split page_type out from _mapcount
2026-05-15 17:57:58 +07:00
unifdef: use memcpy instead of strncpy
2018-12-08 13:05:05 +01:00
ver_linux: rename ver_linux.awk to ver_linux
2016-08-31 13:59:31 +02:00
40df54cf02