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2020-06-01docs/bpf: Add BPF ring buffer design notesAndrii Nakryiko
Add commit description from patch #1 as a stand-alone documentation under Documentation/bpf, as it might be more convenient format, in long term perspective. Suggested-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200529075424.3139988-6-andriin@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-05-23selftests/bpf: Add general instructions for test executionAlan Maguire
Getting a clean BPF selftests run involves ensuring latest trunk LLVM/clang are used, pahole is recent (>=1.16) and config matches the specified config file as closely as possible. Add to bpf_devel_QA.rst and point tools/testing/selftests/bpf/README.rst to it. Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/1590146674-25485-1-git-send-email-alan.maguire@oracle.com
2020-04-28docs: networking: convert filter.txt to ReSTMauro Carvalho Chehab
- add SPDX header; - adjust title markup; - mark code blocks and literals as such; - use footnote markup; - mark tables as such; - adjust identation, whitespaces and blank lines; - add to networking/index.rst. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-30bpf: lsm: Add DocumentationKP Singh
Document how eBPF programs (BPF_PROG_TYPE_LSM) can be loaded and attached (BPF_LSM_MAC) to the LSM hooks. Signed-off-by: KP Singh <kpsingh@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Brendan Jackman <jackmanb@google.com> Reviewed-by: Florent Revest <revest@google.com> Reviewed-by: Thomas Garnier <thgarnie@google.com> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Link: https://lore.kernel.org/bpf/20200329004356.27286-9-kpsingh@chromium.org
2020-03-26bpf: Document bpf_inspect drgn toolAndrey Ignatov
It's a follow-up for discussion in [1]. drgn tool bpf_inspect.py was merged to drgn repo in [2]. Document it in kernel tree to make BPF developers aware that the tool exists and can help with getting BPF state unavailable via UAPI. For now it's just one tool but the doc is written in a way that allows to cover more tools in the future if needed. Please refer to the doc itself for more details. The patch was tested by `make htmldocs` and sanity-checking that resulting html looks good. v2 -> v3: - two sections: "Description" and "Getting started" (Daniel); - add examples in "Getting started" section (Daniel); - add "Customization" section to show how tool can be customized. v1 -> v2: - better "BPF drgn tools" section (Alexei) [1] https://lore.kernel.org/bpf/20200228201514.GB51456@rdna-mbp/T/#mefed65e8a98116bd5d07d09a570a3eac46724951 [2] https://github.com/osandov/drgn/pull/49 Signed-off-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200324185135.1431038-1-rdna@fb.com
2020-02-20docs/bpf: Update bpf development Q/A fileYonghong Song
bpf now has its own mailing list bpf@vger.kernel.org. Update the bpf_devel_QA.rst file to reflect this. Also llvm has switch to github with llvm and clang in the same repo https://github.com/llvm/llvm-project.git. Update the QA file with newer build instructions. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200221004354.930952-1-yhs@fb.com
2019-10-30bpf: Add s390 testing documentationIlya Leoshkevich
This commits adds a document that explains how to test BPF in an s390 QEMU guest. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20191029172916.36528-1-iii@linux.ibm.com
2019-10-07bpf/flow_dissector: add mode to enforce global BPF flow dissectorStanislav Fomichev
Always use init_net flow dissector BPF program if it's attached and fall back to the per-net namespace one. Also, deny installing new programs if there is already one attached to the root namespace. Users can still detach their BPF programs, but can't attach any new ones (-EEXIST). Cc: Petar Penkov <ppenkov@google.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-07-25bpf/flow_dissector: document flagsStanislav Fomichev
Describe what each input flag does and who uses it. Acked-by: Petar Penkov <ppenkov@google.com> Acked-by: Willem de Bruijn <willemb@google.com> Acked-by: Song Liu <songliubraving@fb.com> Cc: Song Liu <songliubraving@fb.com> Cc: Willem de Bruijn <willemb@google.com> Cc: Petar Penkov <ppenkov@google.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-07-11Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds
Pull networking updates from David Miller: "Some highlights from this development cycle: 1) Big refactoring of ipv6 route and neigh handling to support nexthop objects configurable as units from userspace. From David Ahern. 2) Convert explored_states in BPF verifier into a hash table, significantly decreased state held for programs with bpf2bpf calls, from Alexei Starovoitov. 3) Implement bpf_send_signal() helper, from Yonghong Song. 4) Various classifier enhancements to mvpp2 driver, from Maxime Chevallier. 5) Add aRFS support to hns3 driver, from Jian Shen. 6) Fix use after free in inet frags by allocating fqdirs dynamically and reworking how rhashtable dismantle occurs, from Eric Dumazet. 7) Add act_ctinfo packet classifier action, from Kevin Darbyshire-Bryant. 8) Add TFO key backup infrastructure, from Jason Baron. 9) Remove several old and unused ISDN drivers, from Arnd Bergmann. 10) Add devlink notifications for flash update status to mlxsw driver, from Jiri Pirko. 11) Lots of kTLS offload infrastructure fixes, from Jakub Kicinski. 12) Add support for mv88e6250 DSA chips, from Rasmus Villemoes. 13) Various enhancements to ipv6 flow label handling, from Eric Dumazet and Willem de Bruijn. 14) Support TLS offload in nfp driver, from Jakub Kicinski, Dirk van der Merwe, and others. 15) Various improvements to axienet driver including converting it to phylink, from Robert Hancock. 16) Add PTP support to sja1105 DSA driver, from Vladimir Oltean. 17) Add mqprio qdisc offload support to dpaa2-eth, from Ioana Radulescu. 18) Add devlink health reporting to mlx5, from Moshe Shemesh. 19) Convert stmmac over to phylink, from Jose Abreu. 20) Add PTP PHC (Physical Hardware Clock) support to mlxsw, from Shalom Toledo. 21) Add nftables SYNPROXY support, from Fernando Fernandez Mancera. 22) Convert tcp_fastopen over to use SipHash, from Ard Biesheuvel. 23) Track spill/fill of constants in BPF verifier, from Alexei Starovoitov. 24) Support bounded loops in BPF, from Alexei Starovoitov. 25) Various page_pool API fixes and improvements, from Jesper Dangaard Brouer. 26) Just like ipv4, support ref-countless ipv6 route handling. From Wei Wang. 27) Support VLAN offloading in aquantia driver, from Igor Russkikh. 28) Add AF_XDP zero-copy support to mlx5, from Maxim Mikityanskiy. 29) Add flower GRE encap/decap support to nfp driver, from Pieter Jansen van Vuuren. 30) Protect against stack overflow when using act_mirred, from John Hurley. 31) Allow devmap map lookups from eBPF, from Toke Høiland-Jørgensen. 32) Use page_pool API in netsec driver, Ilias Apalodimas. 33) Add Google gve network driver, from Catherine Sullivan. 34) More indirect call avoidance, from Paolo Abeni. 35) Add kTLS TX HW offload support to mlx5, from Tariq Toukan. 36) Add XDP_REDIRECT support to bnxt_en, from Andy Gospodarek. 37) Add MPLS manipulation actions to TC, from John Hurley. 38) Add sending a packet to connection tracking from TC actions, and then allow flower classifier matching on conntrack state. From Paul Blakey. 39) Netfilter hw offload support, from Pablo Neira Ayuso" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (2080 commits) net/mlx5e: Return in default case statement in tx_post_resync_params mlx5: Return -EINVAL when WARN_ON_ONCE triggers in mlx5e_tls_resync(). net: dsa: add support for BRIDGE_MROUTER attribute pkt_sched: Include const.h net: netsec: remove static declaration for netsec_set_tx_de() net: netsec: remove superfluous if statement netfilter: nf_tables: add hardware offload support net: flow_offload: rename tc_cls_flower_offload to flow_cls_offload net: flow_offload: add flow_block_cb_is_busy() and use it net: sched: remove tcf block API drivers: net: use flow block API net: sched: use flow block API net: flow_offload: add flow_block_cb_{priv, incref, decref}() net: flow_offload: add list handling functions net: flow_offload: add flow_block_cb_alloc() and flow_block_cb_free() net: flow_offload: rename TCF_BLOCK_BINDER_TYPE_* to FLOW_BLOCK_BINDER_TYPE_* net: flow_offload: rename TC_BLOCK_{UN}BIND to FLOW_BLOCK_{UN}BIND net: flow_offload: add flow_block_cb_setup_simple() net: hisilicon: Add an tx_desc to adapt HI13X1_GMAC net: hisilicon: Add an rx_desc to adapt HI13X1_GMAC ...
2019-06-27bpf: add sockopt documentationStanislav Fomichev
Provide user documentation about sockopt prog type and cgroup hooks. v9: * add details about setsockopt context and inheritance v7: * add description for retval=0 and optlen=-1 v6: * describe cgroup chaining, add example v2: * use return code 2 for kernel bypass Cc: Andrii Nakryiko <andriin@fb.com> Cc: Martin Lau <kafai@fb.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-06-14Merge tag 'v5.2-rc4' into mauroJonathan Corbet
We need to pick up post-rc1 changes to various document files so they don't get lost in Mauro's massive RST conversion push.
2019-06-08docs: bpf: get rid of two warningsMauro Carvalho Chehab
Documentation/bpf/btf.rst:154: WARNING: Unexpected indentation. Documentation/bpf/btf.rst:163: WARNING: Unexpected indentation. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-05-31bpf: doc: update answer for 32-bit subregister questionJiong Wang
There has been quite a few progress around the two steps mentioned in the answer to the following question: Q: BPF 32-bit subregister requirements This patch updates the answer to reflect what has been done. v2: - Add missing full stop. (Song Liu) - Minor tweak on one sentence. (Song Liu) v1: - Integrated rephrase from Quentin and Jakub Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Jiong Wang <jiong.wang@netronome.com> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-05-14bpf: btf: fix the brackets of BTF_INT_OFFSET()Gary Lin
'VAL' should be protected by the brackets. v2: * Squash the fix for Documentation/bpf/btf.rst Fixes: 69b693f0aefa ("bpf: btf: Introduce BPF Type Format (BTF)") Signed-off-by: Gary Lin <glin@suse.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-05-09docs/btf: fix the missing section marksGary Lin
The section titles of 3.4 and 3.5 are not marked correctly. Signed-off-by: Gary Lin <glin@suse.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-23bpf: document the verifier limitsAlexei Starovoitov
Document the verifier limits. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-04-18bpf: move BPF_PROG_TYPE_FLOW_DISSECTOR documentation to a new common placeStanislav Fomichev
In commit da7031491786 ("bpf: Document BPF_PROG_TYPE_CGROUP_SYSCTL") Andrey proposes to put per-prog type docs under Documentation/bpf/ Let's move flow dissector documentation there as well. Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-18bpf: Document BPF_PROG_TYPE_CGROUP_SYSCTLAndrey Ignatov
Add documentation for BPF_PROG_TYPE_CGROUP_SYSCTL, including general info, attach type, context, return code, helpers, example and usage considerations. A separate file prog_cgroup_sysctl.rst is added to Documentation/bpf/. In the future more program types can be documented in their own prog_<name>.rst files. Another way to place program type specific documentation would be to group program types somehow (e.g. cgroup.rst for all cgroup-bpf programs), but it may not scale well since some program types may belong to different groups, e.g. BPF_PROG_TYPE_CGROUP_SKB can be documented together with either cgroup-bpf programs or programs that access skb. The new file is added to the index and verified by `make htmldocs` / sanity-check by lynx. Signed-off-by: Andrey Ignatov <rdna@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-11Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller
Daniel Borkmann says: ==================== pull-request: bpf-next 2019-04-12 The following pull-request contains BPF updates for your *net-next* tree. The main changes are: 1) Improve BPF verifier scalability for large programs through two optimizations: i) remove verifier states that are not useful in pruning, ii) stop walking parentage chain once first LIVE_READ is seen. Combined gives approx 20x speedup. Increase limits for accepting large programs under root, and add various stress tests, from Alexei. 2) Implement global data support in BPF. This enables static global variables for .data, .rodata and .bss sections to be properly handled which allows for more natural program development. This also opens up the possibility to optimize program workflow by compiling ELFs only once and later only rewriting section data before reload, from Daniel and with test cases and libbpf refactoring from Joe. 3) Add config option to generate BTF type info for vmlinux as part of the kernel build process. DWARF debug info is converted via pahole to BTF. Latter relies on libbpf and makes use of BTF deduplication algorithm which results in 100x savings compared to DWARF data. Resulting .BTF section is typically about 2MB in size, from Andrii. 4) Add BPF verifier support for stack access with variable offset from helpers and add various test cases along with it, from Andrey. 5) Extend bpf_skb_adjust_room() growth BPF helper to mark inner MAC header so that L2 encapsulation can be used for tc tunnels, from Alan. 6) Add support for input __sk_buff context in BPF_PROG_TEST_RUN so that users can define a subset of allowed __sk_buff fields that get fed into the test program, from Stanislav. 7) Add bpf fs multi-dimensional array tests for BTF test suite and fix up various UBSAN warnings in bpftool, from Yonghong. 8) Generate a pkg-config file for libbpf, from Luca. 9) Dump program's BTF id in bpftool, from Prashant. 10) libbpf fix to use smaller BPF log buffer size for AF_XDP's XDP program, from Magnus. 11) kallsyms related fixes for the case when symbols are not present in BPF selftests and samples, from Daniel ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-09bpf: add specification for BTF Var and DataSec kindsDaniel Borkmann
This adds the BTF specification and UAPI bits for supporting BTF Var and DataSec kinds. This is following LLVM upstream commit ac4082b77e07 ("[BPF] Add BTF Var and DataSec Support") which has been merged recently. Var itself is for describing a global variable and DataSec to describe ELF sections e.g. data/bss/rodata sections that hold one or multiple global variables. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-03-26bpf, doc: fix BTF docs reflow of bullet listJesper Dangaard Brouer
Section 2.2.1 BTF_KIND_INT a bullet list was collapsed due to text reflow in commit 9ab5305dbe3f ("docs/btf: reflow text to fill up to 78 characters"). This patch correct the mistake. Also adjust next bullet list, which is used for comparison, to get rendered the same way. Fixes: 9ab5305dbe3f ("docs/btf: reflow text to fill up to 78 characters") Link: https://www.kernel.org/doc/html/latest/bpf/btf.html#btf-kind-int Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-03-02docs/bpf: minor casing/punctuation fixesAndrii Nakryiko
Fix few casing and punctuation glitches. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-03-02docs/btf: reflow text to fill up to 78 charactersAndrii Nakryiko
Reflow paragraphs to more fully and evenly fill 78 character lines. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-03-02docs/btf: fix typos, improve wordingAndrii Nakryiko
Fix various typos, some of the formatting and wording for Documentation/btf.rst. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-01-22bpf: btf: add btf documentationYonghong Song
This patch added documentation for BTF (BPF Debug Format). The document is placed under linux:Documentation/bpf directory. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-01-07bpf, doc: update design qa to reflect kern_version requirementDaniel Borkmann
Update the bpf_design_QA.rst to also reflect recent changes in 6c4fc209fcf9 ("bpf: remove useless version check for prog load"). Suggested-by: Quentin Monnet <quentin.monnet@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-08-07Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller
Daniel Borkmann says: ==================== pull-request: bpf-next 2018-08-07 The following pull-request contains BPF updates for your *net-next* tree. The main changes are: 1) Add cgroup local storage for BPF programs, which provides a fast accessible memory for storing various per-cgroup data like number of transmitted packets, etc, from Roman. 2) Support bpf_get_socket_cookie() BPF helper in several more program types that have a full socket available, from Andrey. 3) Significantly improve the performance of perf events which are reported from BPF offload. Also convert a couple of BPF AF_XDP samples overto use libbpf, both from Jakub. 4) seg6local LWT provides the End.DT6 action, which allows to decapsulate an outer IPv6 header containing a Segment Routing Header. Adds this action now to the seg6local BPF interface, from Mathieu. 5) Do not mark dst register as unbounded in MOV64 instruction when both src and dst register are the same, from Arthur. 6) Define u_smp_rmb() and u_smp_wmb() to their respective barrier instructions on arm64 for the AF_XDP sample code, from Brian. 7) Convert the tcp_client.py and tcp_server.py BPF selftest scripts over from Python 2 to Python 3, from Jeremy. 8) Enable BTF build flags to the BPF sample code Makefile, from Taeung. 9) Remove an unnecessary rcu_read_lock() in run_lwt_bpf(), from Taehee. 10) Several improvements to the README.rst from the BPF documentation to make it more consistent with RST format, from Tobin. 11) Replace all occurrences of strerror() by calls to strerror_r() in libbpf and fix a FORTIFY_SOURCE build error along with it, from Thomas. 12) Fix a bug in bpftool's get_btf() function to correctly propagate an error via PTR_ERR(), from Yue. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-27docs: bpf: Capitalise document headingTobin C. Harding
The majority of files in the kernel documentation index use capitalisation for all words, especially the shorter ones. BPF docs better fit in with the rest of the documentation if the heading is all capitalised. Capitalise document heading. Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-07-27docs: bpf: Add toctree to indexTobin C. Harding
Recently bpf/ docs were converted to us RST format. bp/index.rst was created out of README but toctree was not added to include files within Documentation/bpf/ Add toctree to Documentation/bpf/index.rst Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-07-27docs: bpf: Rename README.rst to index.rstTobin C. Harding
Recently bpf/ docs were converted to use RST format. 'README.rst' was created but in order to fit in with the Sphinx build system this file should be named 'index.rst'. Rename file, fixes to integrate into Sphinx build system in following patches. docs: Rename Documentation/bpf/README.rst to Documentation/bpf/index.rst Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-07-26docs: Update references to netdev-FAQTobin C. Harding
File 'Documentation/networking/netdev-FAQ.txt' has been converted to RST format. We should update all links/references to point to the new file. Update references to netdev-FAQ Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-14bpf, doc: howto use/run the BPF selftestsJesper Dangaard Brouer
I always forget howto run the BPF selftests. Thus, lets add that info to the QA document. Documentation was based on Cilium's documentation: http://cilium.readthedocs.io/en/latest/bpf/#verifying-the-setup Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-14bpf, doc: convert bpf_devel_QA.rst to use RST formattingJesper Dangaard Brouer
Same story as bpf_design_QA.rst RST format conversion. Again thanks to Quentin Monnet <quentin.monnet@netronome.com> for fixes and patches that have been squashed. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-14bpf, doc: convert bpf_design_QA.rst to use RST formattingJesper Dangaard Brouer
The RST formatting is done such that that when rendered or converted to different formats, an automatic index with links are created to the subsections. Thus, the questions are created as sections (or subsections), in-order to get the wanted auto-generated FAQ/QA index. Special thanks to Quentin Monnet <quentin.monnet@netronome.com> who have reviewed and corrected both RST formatting and GitHub rendering issues in this file. Those commits have been squashed. I've manually tested that this also renders nicely if included as part of the kernel 'make htmldocs'. As the end-goal is for this to become more integrated with kernel-doc project/movement. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-14bpf, doc: rename txt files to rst filesJesper Dangaard Brouer
This will cause them to get auto rendered, e.g. when viewing them on GitHub. Followup patches will correct the content to be RST compliant. Also adjust README.rst to point to the renamed files. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-14bpf, doc: add basic README.rst fileJesper Dangaard Brouer
A README.rst file in a directory have special meaning for sites like github, which auto renders the contents. Plus search engines like Google also index these README.rst files. Auto rendering allow us to use links, for (re)directing eBPF users to other places where docs live. The end-goal would be to direct users towards https://www.kernel.org/doc/html/latest but we haven't written the full docs yet, so we start out small and take this incrementally. This directory itself contains some useful docs, which can be linked to from the README.rst file (verified this works for github). Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-04-23bpf: Document sockmap '-target bpf' requirement for PROG_TYPE_SK_MSGJohn Fastabend
BPF_PROG_TYPE_SK_MSG programs use a 'void *' for both data and the data_end pointers. Additionally, the verifier ensures that every accesses into the values is a __u64 read. This correctly maps on to the BPF 64-bit architecture. However, to ensure that when building on 32bit architectures that clang uses correct types the '-target bpf' option _must_ be specified. To make this clear add a note to the Documentation. Signed-off-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-03-20bpf, doc: add description wrt native/bpf clang target and pointer sizeDaniel Borkmann
As this recently came up on netdev [0], lets add it to the BPF devel doc. [0] https://www.spinics.net/lists/netdev/msg489612.html Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-02-02bpf: add documentation to compare clang "-target bpf" and default targetYonghong Song
The added documentation explains how generated codes may differ between clang bpf target and default target, and when to use each target. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2017-12-06bpf, doc: add faq about bpf development processDaniel Borkmann
In the same spirit of netdev FAQ, start a BPF FAQ as a collection of expectations and/or workflow details in the context of BPF patch processing. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2017-11-01bpf: document answers to common questions about BPFAlexei Starovoitov
to address common misconceptions about what BPF is and what it's not add short BPF Q&A that clarifies core BPF design principles and answers some common questions. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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