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2024-06-23bpf, docs: Address comments from IETF Area DirectorsDave Thaler
This patch does the following to address IETF feedback: * Remove mention of "program type" and reference future docs (and mention platform-specific docs exist) for helper functions and BTF. Addresses Roman Danyliw's comments based on GENART review from Ines Robles [0]. * Add reference for endianness as requested by John Scudder [1]. * Added bit numbers to top of 32-bit wide format diagrams as requested by Paul Wouters [2]. * Added more text about why BPF doesn't stand for anything, based on text from ebpf.io [3], as requested by Eric Vyncke and Gunter Van de Velde [4]. * Replaced "htobe16" (and similar) and the direction-specific description with just "be16" (and similar) and a direction-agnostic description, to match the direction-agnostic description in the Byteswap Instructions section. Based on feedback from Eric Vyncke [5]. [0] https://mailarchive.ietf.org/arch/msg/bpf/DvDgDWOiwk05OyNlWlAmELZFPlM/ [1] https://mailarchive.ietf.org/arch/msg/bpf/eKNXpU4jCLjsbZDSw8LjI29M3tM/ [2] https://mailarchive.ietf.org/arch/msg/bpf/hGk8HkYxeZTpdu9qW_MvbGKj7WU/ [3] https://ebpf.io/what-is-ebpf/#what-do-ebpf-and-bpf-stand-for [4] https://mailarchive.ietf.org/arch/msg/bpf/i93lzdN3ewnzzS_JMbinCIYxAIU/ [5] https://mailarchive.ietf.org/arch/msg/bpf/KBWXbMeDcSrq4vsKR_KkBbV6hI4/ Acked-by: David Vernet <void@manifault.com> Signed-off-by: Dave Thaler <dthaler1968@googlemail.com> Link: https://lore.kernel.org/r/20240623150453.10613-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-05-28libbpf: Configure log verbosity with env variableMykyta Yatsenko
Configure logging verbosity by setting LIBBPF_LOG_LEVEL environment variable, which is applied only to default logger. Once user set their custom logging callback, it is up to them to handle filtering. Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240524131840.114289-1-yatsenko@meta.com
2024-05-26bpf, docs: Fix instruction.rst indentationDave Thaler
The table captions patch corrected indented most tables to work with the table directive for adding a caption but missed two of them. Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20240526061815.22497-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-05-25bpf, docs: Clarify call local offsetDave Thaler
In the Jump instructions section it explains that the offset is "relative to the instruction following the jump instruction". But the program-local section confusingly said "referenced by offset from the call instruction, similar to JA". This patch updates that sentence with consistent wording, saying it's relative to the instruction following the call instruction. Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20240525153332.21355-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-05-25bpf, docs: Add table captionsDave Thaler
As suggested by Ines Robles in his IETF GENART review at https://datatracker.ietf.org/doc/review-ietf-bpf-isa-02-genart-lc-robles-2024-05-16/ Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Link: https://lore.kernel.org/r/20240524164618.18894-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-05-25bpf, docs: clarify sign extension of 64-bit use of 32-bit immDave Thaler
imm is defined as a 32-bit signed integer. {MOV, K, ALU64} says it does "dst = src" (where src is 'imm') and it does do dst = (s64)imm, which in that sense does sign extend imm. The MOVSX instruction is explained as sign extending, so added the example of {MOV, K, ALU64} to make this more clear. {JLE, K, JMP} says it does "PC += offset if dst <= src" (where src is 'imm', and the comparison is unsigned). This was apparently ambiguous to some readers as to whether the comparison was "dst <= (u64)(u32)imm" or "dst <= (u64)(s64)imm" so added an example to make this more clear. v1 -> v2: Address comments from Yonghong Signed-off-by: Dave Thaler <dthaler1968@googlemail.com> Acked-by: Yonghong Song <yonghong.song@linux.dev> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20240520215255.10595-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-05-25bpf, docs: Use RFC 2119 language for ISA requirementsDave Thaler
Per IETF convention and discussion at LSF/MM/BPF, use MUST etc. keywords as requested by IETF Area Director review. Also as requested, indicate that documenting BTF is out of scope of this document and will be covered by a separate IETF specification. Added paragraph about the terminology that is required IETF boilerplate and must be worded exactly as such. Signed-off-by: Dave Thaler <dthaler1968@googlemail.com> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20240517165855.4688-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-05-25bpf, docs: Move sentence about returning R0 to abi.rstDave Thaler
As discussed at LSF/MM/BPF, the sentence about using R0 for returning values from calls is part of the calling convention and belongs in abi.rst. Any further additions or clarifications to this text are left for future patches on abi.rst. The current patch is simply to unblock progression of instruction-set.rst to a standard. In contrast, the restriction of register numbers to the range 0-10 is untouched, left in the instruction-set.rst definition of the src_reg and dst_reg fields. Signed-off-by: Dave Thaler <dthaler1968@googlemail.com> Link: https://lore.kernel.org/r/20240517153445.3914-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-05-15bpf, docs: Fix the description of 'src' in ALU instructionsPuranjay Mohan
An ALU instruction's source operand can be the value in the source register or the 32-bit immediate value encoded in the instruction. This is controlled by the 's' bit of the 'opcode'. The current description explicitly uses the phrase 'value of the source register' when defining the meaning of 'src'. Change the description to use 'source operand' in place of 'value of the source register'. Signed-off-by: Puranjay Mohan <puranjay@kernel.org> Acked-by: Dave Thaler <dthaler1968@gmail.com> Link: https://lore.kernel.org/r/20240514130303.113607-1-puranjay@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-29bpf, docs: Clarify PC use in instruction-set.rstDave Thaler
This patch elaborates on the use of PC by expanding the PC acronym, explaining the units, and the relative position to which the offset applies. Signed-off-by: Dave Thaler <dthaler1968@googlemail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/bpf/20240426231126.5130-1-dthaler1968@gmail.com
2024-04-25bpf, docs: Add introduction for use in the ISA Internet DraftDave Thaler
The proposed intro paragraph text is derived from the first paragraph of the IETF BPF WG charter at https://datatracker.ietf.org/wg/bpf/about/ Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20240422190942.24658-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-21bpf, docs: Fix formatting nit in instruction-set.rstDave Thaler
Other places that had pseudocode were prefixed with :: so as to appear in a literal block, but one place was inconsistent. This patch fixes that inconsistency. Signed-off-by: Dave Thaler <dthaler1968@googlemail.com> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20240419213826.7301-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-21bpf, docs: Clarify helper ID and pointer terms in instruction-set.rstDave Thaler
Per IETF 119 meeting discussion and mailing list discussion at https://mailarchive.ietf.org/arch/msg/bpf/2JwWQwFdOeMGv0VTbD0CKWwAOEA/ the following changes are made. First, say call by "static ID" rather than call by "address" Second, change "pointer" to "address" Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20240419203617.6850-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-04-05bpf, docs: Editorial nits in instruction-set.rstDave Thaler
This patch addresses a number of editorial nits including spelling, punctuation, grammar, and wording consistency issues in instruction-set.rst. Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20240405155245.3618-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-03-04bpf, docs: Rename legacy conformance group to packetDave Thaler
There could be other legacy conformance groups in the future, so use a more descriptive name. The status of the conformance group in the IANA registry is what designates it as legacy, not the name of the group. Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Link: https://lore.kernel.org/r/20240302012229.16452-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2024-03-02bpf, docs: Use IETF format for field definitions in instruction-set.rstDave Thaler
In preparation for publication as an IETF RFC, the WG chairs asked me to convert the document to use IETF packet format for field layout, so this patch attempts to make it consistent with other IETF documents. Some fields that are not byte aligned were previously inconsistent in how values were defined. Some were defined as the value of the byte containing the field (like 0x20 for a field holding the high four bits of the byte), and others were defined as the value of the field itself (like 0x2). This PR makes them be consistent in using just the values of the field itself, which is IETF convention. As a result, some of the defines that used BPF_* would no longer match the value in the spec, and so this patch also drops the BPF_* prefix to avoid confusion with the defines that are the full-byte equivalent values. For consistency, BPF_* is then dropped from other fields too. BPF_<foo> is thus the Linux implementation-specific define for <foo> as it appears in the BPF ISA specification. The syntax BPF_ADD | BPF_X | BPF_ALU only worked for full-byte values so the convention {ADD, X, ALU} is proposed for referring to field values instead. Also replace the redundant "LSB bits" with "least significant bits". A preview of what the resulting Internet Draft would look like can be seen at: https://htmlpreview.github.io/?https://raw.githubusercontent.com/dthaler/ebp f-docs-1/format/draft-ietf-bpf-isa.html v1->v2: Fix sphinx issue as recommended by David Vernet Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20240301222337.15931-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-02-29bpf: Replace bpf_lpm_trie_key 0-length array with flexible arrayKees Cook
Replace deprecated 0-length array in struct bpf_lpm_trie_key with flexible array. Found with GCC 13: ../kernel/bpf/lpm_trie.c:207:51: warning: array subscript i is outside array bounds of 'const __u8[0]' {aka 'const unsigned char[]'} [-Warray-bounds=] 207 | *(__be16 *)&key->data[i]); | ^~~~~~~~~~~~~ ../include/uapi/linux/swab.h:102:54: note: in definition of macro '__swab16' 102 | #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x)) | ^ ../include/linux/byteorder/generic.h:97:21: note: in expansion of macro '__be16_to_cpu' 97 | #define be16_to_cpu __be16_to_cpu | ^~~~~~~~~~~~~ ../kernel/bpf/lpm_trie.c:206:28: note: in expansion of macro 'be16_to_cpu' 206 | u16 diff = be16_to_cpu(*(__be16 *)&node->data[i] ^ | ^~~~~~~~~~~ In file included from ../include/linux/bpf.h:7: ../include/uapi/linux/bpf.h:82:17: note: while referencing 'data' 82 | __u8 data[0]; /* Arbitrary size */ | ^~~~ And found at run-time under CONFIG_FORTIFY_SOURCE: UBSAN: array-index-out-of-bounds in kernel/bpf/lpm_trie.c:218:49 index 0 is out of range for type '__u8 [*]' Changing struct bpf_lpm_trie_key is difficult since has been used by userspace. For example, in Cilium: struct egress_gw_policy_key { struct bpf_lpm_trie_key lpm_key; __u32 saddr; __u32 daddr; }; While direct references to the "data" member haven't been found, there are static initializers what include the final member. For example, the "{}" here: struct egress_gw_policy_key in_key = { .lpm_key = { 32 + 24, {} }, .saddr = CLIENT_IP, .daddr = EXTERNAL_SVC_IP & 0Xffffff, }; To avoid the build time and run time warnings seen with a 0-sized trailing array for struct bpf_lpm_trie_key, introduce a new struct that correctly uses a flexible array for the trailing bytes, struct bpf_lpm_trie_key_u8. As part of this, include the "header" portion (which is just the "prefixlen" member), so it can be used by anything building a bpf_lpr_trie_key that has trailing members that aren't a u8 flexible array (like the self-test[1]), which is named struct bpf_lpm_trie_key_hdr. Unfortunately, C++ refuses to parse the __struct_group() helper, so it is not possible to define struct bpf_lpm_trie_key_hdr directly in struct bpf_lpm_trie_key_u8, so we must open-code the union directly. Adjust the kernel code to use struct bpf_lpm_trie_key_u8 through-out, and for the selftest to use struct bpf_lpm_trie_key_hdr. Add a comment to the UAPI header directing folks to the two new options. Reported-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org> Closes: https://paste.debian.net/hidden/ca500597/ Link: https://lore.kernel.org/all/202206281009.4332AA33@keescook/ [1] Link: https://lore.kernel.org/bpf/20240222155612.it.533-kees@kernel.org
2024-02-22bpf, docs: specify which BPF_ABS and BPF_IND fields were zeroDave Thaler
Specifying which fields were unused allows IANA to only list as deprecated instructions that were actually used, leaving the rest as unassigned and possibly available for future use for something else. Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20240221175419.16843-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-02-22bpf, docs: Fix typos in instruction-set.rstDave Thaler
* "BPF ADD" should be "BPF_ADD". * "src" should be "src_reg" in several places. The latter is the field name in the instruction. The former refers to the value of the register, or the immediate. * Add '' around field names in one sentence, for consistency with the rest of the document. Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20240221173535.16601-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-02-13bpf, docs: Update ISA document titleDave Thaler
* Use "Instruction Set Architecture (ISA)" instead of "Instruction Set Specification" * Remove version number As previously discussed on the mailing list at https://mailarchive.ietf.org/arch/msg/bpf/SEpn3OL9TabNRn-4rDX9A6XVbjM/ Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/bpf/20240208221449.12274-1-dthaler1968@gmail.com
2024-02-06bpf, docs: Fix typos in instructions-set.rstDave Thaler
* "imm32" should just be "imm" * Add blank line to fix formatting error reported by Stephen Rothwell [0] [0]: https://lore.kernel.org/bpf/20240206153301.4ead0bad@canb.auug.org.au/T/#u Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20240206045146.4965-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-02-05bpf, docs: Expand set of initial conformance groupsDave Thaler
This patch attempts to update the ISA specification according to the latest mailing list discussion about conformance groups, in a way that is intended to be consistent with IANA registry processes and IETF 118 WG meeting discussion. It does the following: * Split basic into base32 and base64 for 32-bit vs 64-bit base instructions * Split division/multiplication/modulo instructions out of base groups * Split atomic instructions out of base groups There may be additional changes as discussion continues, but there seems to be consensus on the principles above. v1->v2: fixed typo pointed out by David Vernet v2->v3: Moved multiplication to same groups as division/modulo Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20240202221110.3872-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-02-01bpf, docs: Clarify which legacy packet instructions existedDave Thaler
As discussed on the BPF IETF mailing list (see link), this patch updates the "Legacy BPF Packet access instructions" section to clarify which instructions are deprecated (vs which were never defined and so are not deprecated). Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yonghong.song@linux.dev> Acked-by: David Vernet <void@manifault.com> Link: https://mailarchive.ietf.org/arch/msg/bpf/5LnnKm093cGpOmDI9TnLQLBXyys Link: https://lore.kernel.org/bpf/20240131033759.3634-1-dthaler1968@gmail.com
2024-01-31bpf: treewide: Annotate BPF kfuncs in BTFDaniel Xu
This commit marks kfuncs as such inside the .BTF_ids section. The upshot of these annotations is that we'll be able to automatically generate kfunc prototypes for downstream users. The process is as follows: 1. In source, use BTF_KFUNCS_START/END macro pair to mark kfuncs 2. During build, pahole injects into BTF a "bpf_kfunc" BTF_DECL_TAG for each function inside BTF_KFUNCS sets 3. At runtime, vmlinux or module BTF is made available in sysfs 4. At runtime, bpftool (or similar) can look at provided BTF and generate appropriate prototypes for functions with "bpf_kfunc" tag To ensure future kfunc are similarly tagged, we now also return error inside kfunc registration for untagged kfuncs. For vmlinux kfuncs, we also WARN(), as initcall machinery does not handle errors. Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Acked-by: Benjamin Tissoires <bentiss@kernel.org> Link: https://lore.kernel.org/r/e55150ceecbf0a5d961e608941165c0bee7bc943.1706491398.git.dxu@dxuuu.xyz Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-01-29docs/bpf: Improve documentation of 64-bit immediate instructionsYonghong Song
For 64-bit immediate instruction, 'BPF_IMM | BPF_DW | BPF_LD' and src_reg=[0-6], the current documentation describes the 64-bit immediate is constructed by: imm64 = (next_imm << 32) | imm But actually imm64 is only used when src_reg=0. For all other variants (src_reg != 0), 'imm' and 'next_imm' have separate special encoding requirement and imm64 cannot be easily used to describe instruction semantics. This patch clarifies that 64-bit immediate instructions use two 32-bit immediate values instead of a 64-bit immediate value, so later describing individual 64-bit immediate instructions becomes less confusing. Signed-off-by: Yonghong Song <yonghong.song@linux.dev> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Dave Thaler <dthaler1968@gmail.com> Link: https://lore.kernel.org/bpf/20240127194629.737589-1-yonghong.song@linux.dev
2024-01-26bpf, docs: Clarify definitions of various instructionsDave Thaler
Clarify definitions of several instructions: * BPF_NEG does not support BPF_X * BPF_CALL does not support BPF_JMP32 or BPF_X * BPF_EXIT does not support BPF_X * BPF_JA does not support BPF_X (was implied but not explicitly stated) Also fix a typo in the wide instruction figure where the field is actually named "opcode" not "code". Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/bpf/20240126040050.8464-1-dthaler1968@gmail.com
2024-01-23bpf, docs: Clarify that MOVSX is only for BPF_X not BPF_KDave Thaler
Per discussion on the mailing list at https://mailarchive.ietf.org/arch/msg/bpf/uQiqhURdtxV_ZQOTgjCdm-seh74/ the MOVSX operation is only defined to support register extension. The document didn't previously state this and incorrectly implied that one could use an immediate value. Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Acked-by: David Vernet <void@manifault.com> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20240118232954.27206-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-01-23docs/bpf: Fix an incorrect statement in verifier.rstYonghong Song
In verifier.rst, I found an incorrect statement (maybe a typo) in section 'Liveness marks tracking'. Basically, the wrong register is attributed to have a read mark. This may confuse the user. Signed-off-by: Yonghong Song <yonghong.song@linux.dev> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/r/20240111052136.3440417-1-yonghong.song@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-01-23Introduce concept of conformance groupsDave Thaler
The discussion of what the actual conformance groups should be is still in progress, so this is just part 1 which only uses "legacy" for deprecated instructions and "basic" for everything else. Subsequent patches will add more groups as discussion continues. Signed-off-by: Dave Thaler <dthaler1968@gmail.com> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20240108214231.5280-1-dthaler1968@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-01-11Merge tag 'docs-6.8' of git://git.lwn.net/linuxLinus Torvalds
Pull documentation update from Jonathan Corbet: "Another moderately busy cycle for documentation, including: - The minimum Sphinx requirement has been raised to 2.4.4, following a warning that was added in 6.2 - Some reworking of the Documentation/process front page to, hopefully, make it more useful - Various kernel-doc tweaks to, for example, make it deal properly with __counted_by annotations - We have also restored a warning for documentation of nonexistent structure members that disappeared a while back. That had the delightful consequence of adding some 600 warnings to the docs build. A sustained effort by Randy, Vegard, and myself has addressed almost all of those, bringing the documentation back into sync with the code. The fixes are going through the appropriate maintainer trees - Various improvements to the HTML rendered docs, including automatic links to Git revisions and a nice new pulldown to make translations easy to access - Speaking of translations, more of those for Spanish and Chinese ... plus the usual stream of documentation updates and typo fixes" * tag 'docs-6.8' of git://git.lwn.net/linux: (57 commits) MAINTAINERS: use tabs for indent of CONFIDENTIAL COMPUTING THREAT MODEL A reworked process/index.rst ring-buffer/Documentation: Add documentation on buffer_percent file Translated the RISC-V architecture boot documentation. Docs: remove mentions of fdformat from util-linux Docs/zh_CN: Fix the meaning of DEBUG to pr_debug() Documentation: move driver-api/dcdbas to userspace-api/ Documentation: move driver-api/isapnp to userspace-api/ Documentation/core-api : fix typo in workqueue Documentation/trace: Fixed typos in the ftrace FLAGS section kernel-doc: handle a void function without producing a warning scripts/get_abi.pl: ignore some temp files docs: kernel_abi.py: fix command injection scripts/get_abi: fix source path leak CREDITS, MAINTAINERS, docs/process/howto: Update man-pages' maintainer docs: translations: add translations links when they exist kernel-doc: Align quick help and the code MAINTAINERS: add reviewer for Spanish translations docs: ignore __counted_by attribute in structure definitions scripts: kernel-doc: Clarify missing struct member description ..
2023-12-09bpf: Add bpf_cpumask_weight() kfuncDavid Vernet
It can be useful to query how many bits are set in a cpumask. For example, if you want to perform special logic for the last remaining core that's set in a mask. Let's therefore add a new bpf_cpumask_weight() kfunc which checks how many bits are set in a mask. Signed-off-by: David Vernet <void@manifault.com> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20231207210843.168466-2-void@manifault.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-12-01Documentation/bpf: Add documentation for filesystem kfuncsSong Liu
Add a brief introduction for file system kfuncs: bpf_get_file_xattr() bpf_get_fsverity_digest() The documentation highlights the strategy to avoid recursions of these kfuncs. Signed-off-by: Song Liu <song@kernel.org> Link: https://lore.kernel.org/r/20231129234417.856536-4-song@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-11-17docs: automarkup: linkify git revsVegard Nossum
There aren't a ton of references to commits in the documentation, but they do exist, and we can use automarkup to linkify them to make them easier to follow. Use something like this to find references to commits: git grep -P 'commit.*[0-9a-f]{8,}' Documentation/ Also fix a few of these to standardize on the exact format that is already used in changelogs. Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20231027115420.205279-1-vegard.nossum@oracle.com
2023-11-09bpf: Introduce KF_ARG_PTR_TO_CONST_STRSong Liu
Similar to ARG_PTR_TO_CONST_STR for BPF helpers, KF_ARG_PTR_TO_CONST_STR specifies kfunc args that point to const strings. Annotation "__str" is used to specify kfunc arg of type KF_ARG_PTR_TO_CONST_STR. Also, add documentation for the "__str" annotation. bpf_get_file_xattr() will be the first kfunc that uses this type. Signed-off-by: Song Liu <song@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Vadim Fedorenko <vadim.fedorenko@linux.dev> Link: https://lore.kernel.org/bpf/20231107045725.2278852-4-song@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-11-01bpf: Add __bpf_kfunc_{start,end}_defs macrosDave Marchevsky
BPF kfuncs are meant to be called from BPF programs. Accordingly, most kfuncs are not called from anywhere in the kernel, which the -Wmissing-prototypes warning is unhappy about. We've peppered __diag_ignore_all("-Wmissing-prototypes", ... everywhere kfuncs are defined in the codebase to suppress this warning. This patch adds two macros meant to bound one or many kfunc definitions. All existing kfunc definitions which use these __diag calls to suppress -Wmissing-prototypes are migrated to use the newly-introduced macros. A new __diag_ignore_all - for "-Wmissing-declarations" - is added to the __bpf_kfunc_start_defs macro based on feedback from Andrii on an earlier version of this patch [0] and another recent mailing list thread [1]. In the future we might need to ignore different warnings or do other kfunc-specific things. This change will make it easier to make such modifications for all kfunc defs. [0]: https://lore.kernel.org/bpf/CAEf4BzaE5dRWtK6RPLnjTW-MW9sx9K3Fn6uwqCTChK2Dcb1Xig@mail.gmail.com/ [1]: https://lore.kernel.org/bpf/ZT+2qCc%2FaXep0%2FLf@krava/ Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com> Suggested-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Cc: Jiri Olsa <olsajiri@gmail.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Acked-by: David Vernet <void@manifault.com> Acked-by: Yafang Shao <laoar.shao@gmail.com> Link: https://lore.kernel.org/r/20231031215625.2343848-1-davemarchevsky@fb.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-10-19bpf, docs: Define signed modulo as using truncated divisionDave Thaler
There's different mathematical definitions (truncated, floored, rounded, etc.) and different languages have chosen different definitions [0][1]. E.g., languages/libraries that follow Knuth use a different mathematical definition than C uses. This patch specifies which definition BPF uses, as verified by Eduard [2] and others. [0] https://en.wikipedia.org/wiki/Modulo#Variants_of_the_definition [1] https://torstencurdt.com/tech/posts/modulo-of-negative-numbers/ [2] https://lore.kernel.org/bpf/57e6fefadaf3b2995bb259fa8e711c7220ce5290.camel@gmail.com/ Signed-off-by: Dave Thaler <dthaler@microsoft.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: David Vernet <void@manifault.com> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20231017203020.1500-1-dthaler1968@googlemail.com
2023-10-11documentation/bpf: Document cgroup unix socket address hooksDaan De Meyer
Update the documentation to mention the new cgroup unix sockaddr hooks. Signed-off-by: Daan De Meyer <daan.j.demeyer@gmail.com> Link: https://lore.kernel.org/r/20231011185113.140426-8-daan.j.demeyer@gmail.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-09-13docs/bpf: update out-of-date doc in BPF flow dissectorQuan Tian
Commit a5e2151ff9d5 ("net/ipv6: SKB symmetric hash should incorporate transport ports") removed the use of FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL in __skb_get_hash_symmetric(), making the doc out-of-date. Signed-off-by: Quan Tian <qtian@vmware.com> Link: https://lore.kernel.org/r/20230911152353.8280-1-qtian@vmware.com Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-09-07Merge tag 'net-6.6-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net Pull networking updates from Jakub Kicinski: "Including fixes from netfilter and bpf. Current release - regressions: - eth: stmmac: fix failure to probe without MAC interface specified Current release - new code bugs: - docs: netlink: fix missing classic_netlink doc reference Previous releases - regressions: - deal with integer overflows in kmalloc_reserve() - use sk_forward_alloc_get() in sk_get_meminfo() - bpf_sk_storage: fix the missing uncharge in sk_omem_alloc - fib: avoid warn splat in flow dissector after packet mangling - skb_segment: call zero copy functions before using skbuff frags - eth: sfc: check for zero length in EF10 RX prefix Previous releases - always broken: - af_unix: fix msg_controllen test in scm_pidfd_recv() for MSG_CMSG_COMPAT - xsk: fix xsk_build_skb() dereferencing possible ERR_PTR() - netfilter: - nft_exthdr: fix non-linear header modification - xt_u32, xt_sctp: validate user space input - nftables: exthdr: fix 4-byte stack OOB write - nfnetlink_osf: avoid OOB read - one more fix for the garbage collection work from last release - igmp: limit igmpv3_newpack() packet size to IP_MAX_MTU - bpf, sockmap: fix preempt_rt splat when using raw_spin_lock_t - handshake: fix null-deref in handshake_nl_done_doit() - ip: ignore dst hint for multipath routes to ensure packets are hashed across the nexthops - phy: micrel: - correct bit assignments for cable test errata - disable EEE according to the KSZ9477 errata Misc: - docs/bpf: document compile-once-run-everywhere (CO-RE) relocations - Revert "net: macsec: preserve ingress frame ordering", it appears to have been developed against an older kernel, problem doesn't exist upstream" * tag 'net-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (95 commits) net: enetc: distinguish error from valid pointers in enetc_fixup_clear_rss_rfs() Revert "net: team: do not use dynamic lockdep key" net: hns3: remove GSO partial feature bit net: hns3: fix the port information display when sfp is absent net: hns3: fix invalid mutex between tc qdisc and dcb ets command issue net: hns3: fix debugfs concurrency issue between kfree buffer and read net: hns3: fix byte order conversion issue in hclge_dbg_fd_tcam_read() net: hns3: Support query tx timeout threshold by debugfs net: hns3: fix tx timeout issue net: phy: Provide Module 4 KSZ9477 errata (DS80000754C) netfilter: nf_tables: Unbreak audit log reset netfilter: ipset: add the missing IP_SET_HASH_WITH_NET0 macro for ip_set_hash_netportnet.c netfilter: nft_set_rbtree: skip sync GC for new elements in this transaction netfilter: nf_tables: uapi: Describe NFTA_RULE_CHAIN_ID netfilter: nfnetlink_osf: avoid OOB read netfilter: nftables: exthdr: fix 4-byte stack OOB write selftests/bpf: Check bpf_sk_storage has uncharged sk_omem_alloc bpf: bpf_sk_storage: Fix the missing uncharge in sk_omem_alloc bpf: bpf_sk_storage: Fix invalid wait context lockdep report s390/bpf: Pass through tail call counter in trampolines ...
2023-09-01docs/bpf: Fix "file doesn't exist" warnings in {llvm_reloc,btf}.rstEduard Zingerman
scripts/documentation-file-ref-check reports warnings for (valid) cross-links of form: :ref:`Documentation/bpf/btf <BTF_Ext_Section>` Adding extension to the file name helps to avoid the warning, e.g: :ref:`Documentation/bpf/btf.rst <BTF_Ext_Section>` Fixes: be4033d36070 ("docs/bpf: Add description for CO-RE relocations") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jiri Olsa <jolsa@kernel.org> Closes: https://lore.kernel.org/oe-kbuild-all/202309010804.G3MpXo59-lkp@intel.com Link: https://lore.kernel.org/bpf/20230901125935.487972-1-eddyz87@gmail.com
2023-08-30Merge tag 'docs-6.6' of git://git.lwn.net/linuxLinus Torvalds
Pull documentation updates from Jonathan Corbet: "Documentation work keeps chugging along; this includes: - Work from Carlos Bilbao to integrate rustdoc output into the generated HTML documentation. This took some work to figure out how to do it without slowing the docs build and without creating people who don't have Rust installed, but Carlos got there - Move the loongarch and mips architecture documentation under Documentation/arch/ - Some more maintainer documentation from Jakub ... plus the usual assortment of updates, translations, and fixes" * tag 'docs-6.6' of git://git.lwn.net/linux: (56 commits) Docu: genericirq.rst: fix irq-example input: docs: pxrc: remove reference to phoenix-sim Documentation: serial-console: Fix literal block marker docs/mm: remove references to hmm_mirror ops and clean typos docs/zh_CN: correct regi_chg(),regi_add() to region_chg(),region_add() Documentation: Fix typos Documentation/ABI: Fix typos scripts: kernel-doc: fix macro handling in enums scripts: kernel-doc: parse DEFINE_DMA_UNMAP_[ADDR|LEN] Documentation: riscv: Update boot image header since EFI stub is supported Documentation: riscv: Add early boot document Documentation: arm: Add bootargs to the table of added DT parameters docs: kernel-parameters: Refer to the correct bitmap function doc: update params of memhp_default_state= docs: Add book to process/kernel-docs.rst docs: sparse: fix invalid link addresses docs: vfs: clean up after the iterate() removal docs: Add a section on surveys to the researcher guidelines docs: move mips under arch docs: move loongarch under arch ...
2023-08-30bpf, docs: s/eBPF/BPF in standards documentsDavid Vernet
There isn't really anything other than just "BPF" at this point, so referring to it as "eBPF" in our standards document just causes unnecessary confusion. Let's just be consistent and use "BPF". Suggested-by: Will Hawkins <hawkinsw@obs.cr> Signed-off-by: David Vernet <void@manifault.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230828155948.123405-4-void@manifault.com
2023-08-30bpf, docs: Add abi.rst document to standardization subdirectoryDavid Vernet
As specified in the IETF BPF charter, the BPF working group has plans to add one or more informational documents that recommend conventions and guidelines for producing portable BPF program binaries. The instruction-set.rst document currently contains a "Registers and calling convention" subsection which dictates a calling convention that belongs in an ABI document, rather than an instruction set document. Let's move it to a new abi.rst document so we can clean it up. The abi.rst document will of course be significantly changed and expanded upon over time. For now, it's really just a placeholder which will contain ABI-specific language that doesn't belong in other documents. Signed-off-by: David Vernet <void@manifault.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230828155948.123405-3-void@manifault.com
2023-08-30bpf, docs: Move linux-notes.rst to root bpf docs treeDavid Vernet
In commit 4d496be9ca05 ("bpf,docs: Create new standardization subdirectory"), I added a standardization/ directory to the BPF documentation, which will contain the docs that will be standardized as part of the effort with the IETF. I included linux-notes.rst in that directory, but I shouldn't have. It doesn't contain anything that will be standardized. Let's move it back to Documentation/bpf. Signed-off-by: David Vernet <void@manifault.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230828155948.123405-2-void@manifault.com
2023-08-30docs/bpf: Add description for CO-RE relocationsEduard Zingerman
Add a section on CO-RE relocations to llvm_relo.rst. Describe relevant .BTF.ext structure, `enum bpf_core_relo_kind` and `struct bpf_core_relo` in some detail. Description is based on doc-strings from: - include/uapi/linux/bpf.h:struct bpf_core_relo - tools/lib/bpf/relo_core.c:__bpf_core_types_match() Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/bpf/20230826222912.2560865-2-eddyz87@gmail.com
2023-08-30bpf, docs: Correct source of offset for program-local callWill Hawkins
The offset to use when calculating the target of a program-local call is in the instruction's imm field, not its offset field. Signed-off-by: Will Hawkins <hawkinsw@obs.cr> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/bpf/20230826053258.1860167-1-hawkinsw@obs.cr
2023-08-18Documentation: Fix typosBjorn Helgaas
Fix typos in Documentation. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Link: https://lore.kernel.org/r/20230814212822.193684-4-helgaas@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2023-08-08bpf, docs: Fix small typo and define semantics of sign extensionWill Hawkins
Add additional precision on the semantics of the sign extension operations in BPF. In addition, fix a very minor typo. Signed-off-by: Will Hawkins <hawkinsw@obs.cr> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20230808212503.197834-1-hawkinsw@obs.cr Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-08-07bpf, docs: Formalize type notation and function semantics in ISA standardWill Hawkins
Give a single place where the shorthand for types are defined and the semantics of helper functions are described. Signed-off-by: Will Hawkins <hawkinsw@obs.cr> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20230807140651.122484-1-hawkinsw@obs.cr Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-07-29docs/bpf: Fix malformed documentationYonghong Song
Two issues are fixed: 1. Malformed table due to newly-introduced BPF_MOVSX 2. Missing reference link for ``Sign-extension load operations`` Fixes: 245d4c40c09b ("docs/bpf: Add documentation for new instructions") Cc: bpf@ietf.org Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202307291840.Cqhj7uox-lkp@intel.com/ Signed-off-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20230730004251.381307-1-yonghong.song@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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