From: Will Hawkins <hawkinsw@obs.cr>
Date: Sat, 26 Aug 2023 01:32:54 -0400
Subject: bpf, docs: Correct source of offset for program-local call
Patch-mainline: v6.6-rc1
Git-commit: 2d71a90f7e0fa3cd348602a36f6eb1237ab7cebb
References: jsc#PED-6811
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
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
Documentation/bpf/standardization/instruction-set.rst | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- 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 ds
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
===========================