diff options
| author | Will Hawkins <hawkinsw@obs.cr> | 2023-08-26 01:32:54 -0400 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2023-08-30 09:49:53 +0200 |
| commit | 2d71a90f7e0fa3cd348602a36f6eb1237ab7cebb (patch) | |
| tree | 6be4f228ed36d9cecdc7981ed606d4b6c7fa7cb9 /Documentation | |
| parent | 5439cfa7fe612e7d02d5a1234feda3fa6e483ba7 (diff) | |
bpf, docs: Correct source of offset for program-local call
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
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/bpf/standardization/instruction-set.rst | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/Documentation/bpf/standardization/instruction-set.rst b/Documentation/bpf/standardization/instruction-set.rst index 4f73e9dc8d9e..c5b0b2011f16 100644 --- a/Documentation/bpf/standardization/instruction-set.rst +++ b/Documentation/bpf/standardization/instruction-set.rst @@ -373,7 +373,7 @@ 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 see `Helper functions`_ -BPF_CALL 0x8 0x1 call PC += offset see `Program-local functions`_ +BPF_CALL 0x8 0x1 call PC += imm see `Program-local functions`_ BPF_CALL 0x8 0x2 call helper function by BTF ID see `Helper functions`_ BPF_EXIT 0x9 0x0 return BPF_JMP only BPF_JLT 0xa any PC += offset if dst < src unsigned @@ -424,8 +424,8 @@ Program-local functions ~~~~~~~~~~~~~~~~~~~~~~~ Program-local functions are functions exposed by the same BPF program as the caller, and are referenced by offset from the call instruction, similar to -``BPF_JA``. A ``BPF_EXIT`` within the program-local function will return to -the caller. +``BPF_JA``. The offset is encoded in the imm field of the call instruction. +A ``BPF_EXIT`` within the program-local function will return to the caller. Load and store instructions =========================== |