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>
* "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>
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>
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
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
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
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>
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
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
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
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>
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>
Improve documentation for cpu=v4 instructions based on
David's suggestions.
Cc: bpf@ietf.org
Suggested-by: David Vernet <void@manifault.com>
Acked-by: David Vernet <void@manifault.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728225105.919595-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add documentation in instruction-set.rst for new instruction encoding
and their corresponding operations. Also removed the question
related to 'no BPF_SDIV' in bpf_design_QA.rst since we have
BPF_SDIV insn now.
Cc: bpf@ietf.org
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230728011342.3724411-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch fixes the documentation of the BPF_NEG instruction to
denote that it does not use the source register operand.
Signed-off-by: Jose E. Marchesi <jose.marchesi@oracle.com>
Acked-by: Dave Thaler <dthaler@microsoft.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20230726092543.6362-1-jose.marchesi@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The BPF standardization effort is actively underway with the IETF. As
described in the BPF Working Group (WG) charter in [0], there are a
number of proposed documents, some informational and some proposed
standards, that will be drafted as part of the standardization effort.
[0]: https://datatracker.ietf.org/wg/bpf/about/
Though the specific documents that will formally be standardized will
exist as Internet Drafts (I-D) and WG documents in the BPF WG
datatracker page, the source of truth from where those documents will be
generated will reside in the kernel documentation tree (originating in
the bpf-next tree).
Because these documents will be used to generate the I-D and WG
documents which will be standardized with the IETF, they are a bit
special as far as kernel-tree documentation goes:
- They will be dual licensed with LGPL-2.1 OR BSD-2-Clause
- IETF I-D and WG documents (the documents which will actually be
standardized) will be auto-generated from these documents.
In order to keep things clearly organized in the BPF documentation tree,
and to make it abundantly clear where standards-related documentation
needs to go, we should move standards-relevant documents into a separate
standardization/ subdirectory.
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230710183027.15132-1-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Dave Thaler