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Martin KaFai Lau f80442a4cd bpf: btf: Change how section is supported in btf_header
There are currently unused section descriptions in the btf_header.  Those
sections are here to support future BTF use cases.  For example, the
func section (func_off) is to support function signature (e.g. the BPF
prog function signature).

Instead of spelling out all potential sections up-front in the btf_header.
This patch makes changes to btf_header such that extending it (e.g. adding
a section) is possible later.  The unused ones can be removed for now and
they can be added back later.

This patch:
1. adds a hdr_len to the btf_header.  It will allow adding
sections (and other info like parent_label and parent_name)
later.  The check is similar to the existing bpf_attr.
If a user passes in a longer hdr_len, the kernel
ensures the extra tailing bytes are 0.

2. allows the section order in the BTF object to be
different from its sec_off order in btf_header.

3. each sec_off is followed by a sec_len.  It must not have gap or
overlapping among sections.

The string section is ensured to be at the end due to the 4 bytes
alignment requirement of the type section.

The above changes will allow enough flexibility to
add new sections (and other info) to the btf_header later.

This patch also removes an unnecessary !err check
at the end of btf_parse().

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-05-23 12:03:31 +02:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2018-05-16 22:47:11 -04:00
block blk-mq: fix sysfs inflight counter 2018-04-26 09:02:01 -06:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto crypto: drbg - set freed buffers to NULL 2018-04-21 00:57:00 +08:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2018-05-16 22:47:11 -04:00
drivers nfp: bpf: support arithmetic indirect right shift (BPF_ARSH | BPF_X) 2018-05-18 21:35:55 +02:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs vmcore: append device dumps to vmcore as elf notes 2018-05-14 13:46:04 -04:00
include bpf: btf: Change how section is supported in btf_header 2018-05-23 12:03:31 +02:00
init Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2018-05-16 22:47:11 -04:00
ipc ipc/shm: fix use-after-free of shm file via remap_file_pages() 2018-04-13 17:10:27 -07:00
kernel bpf: btf: Change how section is supported in btf_header 2018-05-23 12:03:31 +02:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2018-05-07 23:35:08 -04:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
mm mmap: introduce sane default mmap limits 2018-05-11 09:52:01 -07:00
net bpf: Add mtu checking to FIB forwarding helper 2018-05-22 10:51:09 +02:00
samples samples/bpf: adapt xdpsock to the new uapi 2018-05-22 10:25:06 +02:00
scripts bpf: change eBPF helper doc parsing script to allow for smaller indent 2018-05-17 17:34:43 +02:00
security net: initial AF_XDP skeleton 2018-05-03 15:55:23 -07:00
sound ALSA: pcm: Check PCM state at xfern compat ioctl 2018-05-02 08:54:54 +02:00
tools bpf: add sk_msg prog sk access tests to test_verifier 2018-05-18 22:44:11 +02:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt KVM/arm fixes for 4.17, take #2 2018-05-05 23:05:31 +02:00
.clang-format clang-format: add configuration file 2018-04-11 10:28:35 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap Merge candidates for 4.17 merge window 2018-04-06 17:35:43 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS/CREDITS: Drop METAG ARCHITECTURE 2018-03-05 16:34:24 +00:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS MAINTAINERS: Add entry for Microsemi Ethernet switches 2018-05-15 16:41:15 -04:00
Makefile Linux 4.17-rc4 2018-05-06 16:57:38 -10:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.