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bpf, docs: Fix typos in instruction-set.rst 

* "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 commit is contained in:
Dave Thaler 2024-02-21 09:35:35 -08:00 committed by Alexei Starovoitov
parent 8425b6eb51
commit c1bb68f6b2
1 changed files with 37 additions and 37 deletions
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74
Documentation/bpf/standardization/instruction-set.rst
View File

@ -178,8 +178,8 @@ Unused fields shall be cleared to zero.
As discussed below in `64-bit immediate instructions`_, a 64-bit immediate
instruction uses two 32-bit immediate values that are constructed as follows.
The 64 bits following the basic instruction contain a pseudo instruction
using the same format but with opcode, dst_reg, src_reg, and offset all set to zero,
and imm containing the high 32 bits of the immediate value.
using the same format but with 'opcode', 'dst_reg', 'src_reg', and 'offset' all
set to zero, and imm containing the high 32 bits of the immediate value.
This is depicted in the following figure::
@ -392,27 +392,27 @@ otherwise identical operations, and indicates the base64 conformance
group unless otherwise specified.
The 'code' field encodes the operation as below:
======== ===== === =============================== =============================================
code value src description notes
======== ===== === =============================== =============================================
BPF_JA 0x0 0x0 PC += offset BPF_JMP | BPF_K only
BPF_JA 0x0 0x0 PC += imm BPF_JMP32 | BPF_K only
BPF_JEQ 0x1 any PC += offset if dst == src
BPF_JGT 0x2 any PC += offset if dst > src unsigned
BPF_JGE 0x3 any PC += offset if dst >= src unsigned
BPF_JSET 0x4 any PC += offset if dst & src
BPF_JNE 0x5 any PC += offset if dst != src
BPF_JSGT 0x6 any PC += offset if dst > src signed
BPF_JSGE 0x7 any PC += offset if dst >= src signed
BPF_CALL 0x8 0x0 call helper function by address BPF_JMP | BPF_K only, see `Helper functions`_
BPF_CALL 0x8 0x1 call PC += imm BPF_JMP | BPF_K only, see `Program-local functions`_
BPF_CALL 0x8 0x2 call helper function by BTF ID BPF_JMP | BPF_K only, see `Helper functions`_
BPF_EXIT 0x9 0x0 return BPF_JMP | BPF_K only
BPF_JLT 0xa any PC += offset if dst < src unsigned
BPF_JLE 0xb any PC += offset if dst <= src unsigned
BPF_JSLT 0xc any PC += offset if dst < src signed
BPF_JSLE 0xd any PC += offset if dst <= src signed
======== ===== === =============================== =============================================
======== ===== ======= =============================== =============================================
code value src_reg description notes
======== ===== ======= =============================== =============================================
BPF_JA 0x0 0x0 PC += offset BPF_JMP | BPF_K only
BPF_JA 0x0 0x0 PC += imm BPF_JMP32 | BPF_K only
BPF_JEQ 0x1 any PC += offset if dst == src
BPF_JGT 0x2 any PC += offset if dst > src unsigned
BPF_JGE 0x3 any PC += offset if dst >= src unsigned
BPF_JSET 0x4 any PC += offset if dst & src
BPF_JNE 0x5 any PC += offset if dst != src
BPF_JSGT 0x6 any PC += offset if dst > src signed
BPF_JSGE 0x7 any PC += offset if dst >= src signed
BPF_CALL 0x8 0x0 call helper function by address BPF_JMP | BPF_K only, see `Helper functions`_
BPF_CALL 0x8 0x1 call PC += imm BPF_JMP | BPF_K only, see `Program-local functions`_
BPF_CALL 0x8 0x2 call helper function by BTF ID BPF_JMP | BPF_K only, see `Helper functions`_
BPF_EXIT 0x9 0x0 return BPF_JMP | BPF_K only
BPF_JLT 0xa any PC += offset if dst < src unsigned
BPF_JLE 0xb any PC += offset if dst <= src unsigned
BPF_JSLT 0xc any PC += offset if dst < src signed
BPF_JSLE 0xd any PC += offset if dst <= src signed
======== ===== ======= =============================== =============================================
The BPF program needs to store the return value into register R0 before doing a
``BPF_EXIT``.
@ -568,7 +568,7 @@ BPF_XOR 0xa0 atomic xor
*(u32 *)(dst + offset) += src
``BPF_ATOMIC | BPF_DW | BPF_STX`` with 'imm' = BPF ADD means::
``BPF_ATOMIC | BPF_DW | BPF_STX`` with 'imm' = BPF_ADD means::
*(u64 *)(dst + offset) += src
@ -601,24 +601,24 @@ and loaded back to ``R0``.
-----------------------------
Instructions with the ``BPF_IMM`` 'mode' modifier use the wide instruction
encoding defined in `Instruction encoding`_, and use the 'src' field of the
encoding defined in `Instruction encoding`_, and use the 'src_reg' field of the
basic instruction to hold an opcode subtype.
The following table defines a set of ``BPF_IMM | BPF_DW | BPF_LD`` instructions
with opcode subtypes in the 'src' field, using new terms such as "map"
with opcode subtypes in the 'src_reg' field, using new terms such as "map"
defined further below:
========================= ====== === ========================================= =========== ==============
opcode construction opcode src pseudocode imm type dst type
========================= ====== === ========================================= =========== ==============
BPF_IMM | BPF_DW | BPF_LD 0x18 0x0 dst = (next_imm << 32) | imm integer integer
BPF_IMM | BPF_DW | BPF_LD 0x18 0x1 dst = map_by_fd(imm) map fd map
BPF_IMM | BPF_DW | BPF_LD 0x18 0x2 dst = map_val(map_by_fd(imm)) + next_imm map fd data pointer
BPF_IMM | BPF_DW | BPF_LD 0x18 0x3 dst = var_addr(imm) variable id data pointer
BPF_IMM | BPF_DW | BPF_LD 0x18 0x4 dst = code_addr(imm) integer code pointer
BPF_IMM | BPF_DW | BPF_LD 0x18 0x5 dst = map_by_idx(imm) map index map
BPF_IMM | BPF_DW | BPF_LD 0x18 0x6 dst = map_val(map_by_idx(imm)) + next_imm map index data pointer
========================= ====== === ========================================= =========== ==============
========================= ====== ======= ========================================= =========== ==============
opcode construction opcode src_reg pseudocode imm type dst type
========================= ====== ======= ========================================= =========== ==============
BPF_IMM | BPF_DW | BPF_LD 0x18 0x0 dst = (next_imm << 32) | imm integer integer
BPF_IMM | BPF_DW | BPF_LD 0x18 0x1 dst = map_by_fd(imm) map fd map
BPF_IMM | BPF_DW | BPF_LD 0x18 0x2 dst = map_val(map_by_fd(imm)) + next_imm map fd data pointer
BPF_IMM | BPF_DW | BPF_LD 0x18 0x3 dst = var_addr(imm) variable id data pointer
BPF_IMM | BPF_DW | BPF_LD 0x18 0x4 dst = code_addr(imm) integer code pointer
BPF_IMM | BPF_DW | BPF_LD 0x18 0x5 dst = map_by_idx(imm) map index map
BPF_IMM | BPF_DW | BPF_LD 0x18 0x6 dst = map_val(map_by_idx(imm)) + next_imm map index data pointer
========================= ====== ======= ========================================= =========== ==============
where