From 4e4136c6446753e6da4424a734f84de82c70600f Mon Sep 17 00:00:00 2001 From: Amery Hung Date: Tue, 25 Feb 2025 15:35:45 -0800 Subject: selftests/bpf: Test gen_pro/epilogue that generate kfuncs Test gen_prologue and gen_epilogue that generate kfuncs that have not been seen in the main program. The main bpf program and return value checks are identical to pro_epilogue.c introduced in commit 47e69431b57a ("selftests/bpf: Test gen_prologue and gen_epilogue"). However, now when bpf_testmod_st_ops detects a program name with prefix "test_kfunc_", it generates slightly different prologue and epilogue: They still add 1000 to args->a in prologue, add 10000 to args->a and set r0 to 2 * args->a in epilogue, but involve kfuncs. At high level, the alternative version of prologue and epilogue look like this: cgrp = bpf_cgroup_from_id(0); if (cgrp) bpf_cgroup_release(cgrp); else /* Perform what original bpf_testmod_st_ops prologue or * epilogue does */ Since 0 is never a valid cgroup id, the original prologue or epilogue logic will be performed. As a result, the __retval check should expect the exact same return value. Signed-off-by: Amery Hung Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20250225233545.285481-2-ameryhung@gmail.com Signed-off-by: Alexei Starovoitov --- include/linux/filter.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include/linux') diff --git a/include/linux/filter.h b/include/linux/filter.h index a3ea46281595..3ed6eb9e7c73 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -469,6 +469,16 @@ static inline bool insn_is_cast_user(const struct bpf_insn *insn) .off = 0, \ .imm = BPF_CALL_IMM(FUNC) }) +/* Kfunc call */ + +#define BPF_CALL_KFUNC(OFF, IMM) \ + ((struct bpf_insn) { \ + .code = BPF_JMP | BPF_CALL, \ + .dst_reg = 0, \ + .src_reg = BPF_PSEUDO_KFUNC_CALL, \ + .off = OFF, \ + .imm = IMM }) + /* Raw code statement block */ #define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM) \ -- cgit v1.2.3