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| author |  Dave Thaler <dthaler1968@googlemail.com>
| 2024-04-19 13:36:17 -0700 |
|---|---|---|
| committer |  Alexei Starovoitov <ast@kernel.org>
| 2024-04-21 10:08:56 -0700 |
| commit | db50040d09cc511889b2c949a0c93d017e44f081 (patch) | |
| tree | dac684be17e5cff7f0713a1b524859fd2321ff15 /Documentation/bpf | |
| parent | Merge branch 'use network helpers, part 1' (diff) | |
| download | linux-db50040d09cc511889b2c949a0c93d017e44f081.tar.gz linux-db50040d09cc511889b2c949a0c93d017e44f081.tar.bz2 linux-db50040d09cc511889b2c949a0c93d017e44f081.zip | |
bpf, docs: Clarify helper ID and pointer terms in instruction-set.rst
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>
Diffstat (limited to 'Documentation/bpf')
| -rw-r--r-- | Documentation/bpf/standardization/instruction-set.rst | 48 |
1 files changed, 24 insertions, 24 deletions
diff --git a/Documentation/bpf/standardization/instruction-set.rst b/Documentation/bpf/standardization/instruction-set.rst index 8d0781f0bd17..1f92551a34b9 100644 --- a/Documentation/bpf/standardization/instruction-set.rst +++ b/Documentation/bpf/standardization/instruction-set.rst @@ -443,27 +443,27 @@ otherwise identical operations, and indicates the base64 conformance group unless otherwise specified. The 'code' field encodes the operation as below: -======== ===== ======= =============================== =================================================== -code value src_reg description notes -======== ===== ======= =============================== =================================================== -JA 0x0 0x0 PC += offset {JA, K, JMP} only -JA 0x0 0x0 PC += imm {JA, K, JMP32} only +======== ===== ======= ================================= =================================================== +code value src_reg description notes +======== ===== ======= ================================= =================================================== +JA 0x0 0x0 PC += offset {JA, K, JMP} only +JA 0x0 0x0 PC += imm {JA, K, JMP32} only JEQ 0x1 any PC += offset if dst == src -JGT 0x2 any PC += offset if dst > src unsigned -JGE 0x3 any PC += offset if dst >= src unsigned +JGT 0x2 any PC += offset if dst > src unsigned +JGE 0x3 any PC += offset if dst >= src unsigned JSET 0x4 any PC += offset if dst & src JNE 0x5 any PC += offset if dst != src -JSGT 0x6 any PC += offset if dst > src signed -JSGE 0x7 any PC += offset if dst >= src signed -CALL 0x8 0x0 call helper function by address {CALL, K, JMP} only, see `Helper functions`_ -CALL 0x8 0x1 call PC += imm {CALL, K, JMP} only, see `Program-local functions`_ -CALL 0x8 0x2 call helper function by BTF ID {CALL, K, JMP} only, see `Helper functions`_ -EXIT 0x9 0x0 return {CALL, K, JMP} only -JLT 0xa any PC += offset if dst < src unsigned -JLE 0xb any PC += offset if dst <= src unsigned -JSLT 0xc any PC += offset if dst < src signed -JSLE 0xd any PC += offset if dst <= src signed -======== ===== ======= =============================== =================================================== +JSGT 0x6 any PC += offset if dst > src signed +JSGE 0x7 any PC += offset if dst >= src signed +CALL 0x8 0x0 call helper function by static ID {CALL, K, JMP} only, see `Helper functions`_ +CALL 0x8 0x1 call PC += imm {CALL, K, JMP} only, see `Program-local functions`_ +CALL 0x8 0x2 call helper function by BTF ID {CALL, K, JMP} only, see `Helper functions`_ +EXIT 0x9 0x0 return {CALL, K, JMP} only +JLT 0xa any PC += offset if dst < src unsigned +JLE 0xb any PC += offset if dst <= src unsigned +JSLT 0xc any PC += offset if dst < src signed +JSLE 0xd any PC += offset if dst <= src signed +======== ===== ======= ================================= =================================================== The BPF program needs to store the return value into register R0 before doing an ``EXIT``. @@ -498,9 +498,9 @@ Helper functions Helper functions are a concept whereby BPF programs can call into a set of function calls exposed by the underlying platform. -Historically, each helper function was identified by an address +Historically, each helper function was identified by a static ID encoded in the 'imm' field. The available helper functions may differ -for each program type, but address values are unique across all program types. +for each program type, but static IDs are unique across all program types. Platforms that support the BPF Type Format (BTF) support identifying a helper function by a BTF ID encoded in the 'imm' field, where the BTF ID @@ -667,11 +667,11 @@ src_reg pseudocode imm type dst type ======= ========================================= =========== ============== 0x0 dst = (next_imm << 32) | imm integer integer 0x1 dst = map_by_fd(imm) map fd map -0x2 dst = map_val(map_by_fd(imm)) + next_imm map fd data pointer -0x3 dst = var_addr(imm) variable id data pointer -0x4 dst = code_addr(imm) integer code pointer +0x2 dst = map_val(map_by_fd(imm)) + next_imm map fd data address +0x3 dst = var_addr(imm) variable id data address +0x4 dst = code_addr(imm) integer code address 0x5 dst = map_by_idx(imm) map index map -0x6 dst = map_val(map_by_idx(imm)) + next_imm map index data pointer +0x6 dst = map_val(map_by_idx(imm)) + next_imm map index data address ======= ========================================= =========== ============== where |