Currently, MAX_BPF_FUNC_ARGS is used for tracepoint related progs where the number of parameters cannot exceed MAX_BPF_FUNC_ARGS. Here, MAX_BPF_FUNC_ARGS is reused to set a limit of the number of arguments for bpf functions and kfuncs. The current value for MAX_BPF_FUNC_ARGS is 12 which should be sufficient for majority of bpf functions and kfuncs. Acked-by: Puranjay Mohan Acked-by: Kumar Kartikeya Dwivedi Signed-off-by: Yonghong Song --- include/linux/bpf.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 3cb6b9e70080..c8e387b0ce46 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1151,6 +1151,11 @@ struct bpf_prog_offload { /* The longest tracepoint has 12 args. * See include/trace/bpf_probe.h + * + * Also reuse this macro for maximum number of arguments a BPF function + * or a kfunc can have. Args 1-5 are passed in registers, args 6-12 via + * stack arg slots. The JIT may map some stack arg slots to registers based + * on the native calling convention (e.g., arg 6 to R9 on x86-64). */ #define MAX_BPF_FUNC_ARGS 12 -- 2.52.0