From 17bda53e43bc41d881ca6a02b3c6f5376c55b3d3 Mon Sep 17 00:00:00 2001 From: Hou Tao Date: Fri, 5 Jan 2024 18:48:19 +0800 Subject: selftests/bpf: Test the inlining of bpf_kptr_xchg() The test uses bpf_prog_get_info_by_fd() to obtain the xlated instructions of the program first. Since these instructions have already been rewritten by the verifier, the tests then checks whether the rewritten instructions are as expected. And to ensure LLVM generates code exactly as expected, use inline assembly and a naked function. Suggested-by: Eduard Zingerman Signed-off-by: Hou Tao Acked-by: Eduard Zingerman Link: https://lore.kernel.org/r/20240105104819.3916743-4-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/kptr_xchg_inline.c | 51 ++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/kptr_xchg_inline.c (limited to 'tools/testing/selftests/bpf/prog_tests') diff --git a/tools/testing/selftests/bpf/prog_tests/kptr_xchg_inline.c b/tools/testing/selftests/bpf/prog_tests/kptr_xchg_inline.c new file mode 100644 index 000000000000..5a4bee1cf970 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/kptr_xchg_inline.c @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) 2023. Huawei Technologies Co., Ltd */ +#include + +#include "linux/filter.h" +#include "kptr_xchg_inline.skel.h" + +void test_kptr_xchg_inline(void) +{ + struct kptr_xchg_inline *skel; + struct bpf_insn *insn = NULL; + struct bpf_insn exp; + unsigned int cnt; + int err; + +#if !defined(__x86_64__) + test__skip(); + return; +#endif + + skel = kptr_xchg_inline__open_and_load(); + if (!ASSERT_OK_PTR(skel, "open_load")) + return; + + err = get_xlated_program(bpf_program__fd(skel->progs.kptr_xchg_inline), &insn, &cnt); + if (!ASSERT_OK(err, "prog insn")) + goto out; + + /* The original instructions are: + * r1 = map[id:xxx][0]+0 + * r2 = 0 + * call bpf_kptr_xchg#yyy + * + * call bpf_kptr_xchg#yyy will be inlined as: + * r0 = r2 + * r0 = atomic64_xchg((u64 *)(r1 +0), r0) + */ + if (!ASSERT_GT(cnt, 5, "insn cnt")) + goto out; + + exp = BPF_MOV64_REG(BPF_REG_0, BPF_REG_2); + if (!ASSERT_OK(memcmp(&insn[3], &exp, sizeof(exp)), "mov")) + goto out; + + exp = BPF_ATOMIC_OP(BPF_DW, BPF_XCHG, BPF_REG_1, BPF_REG_0, 0); + if (!ASSERT_OK(memcmp(&insn[4], &exp, sizeof(exp)), "xchg")) + goto out; +out: + free(insn); + kptr_xchg_inline__destroy(skel); +} -- cgit v1.2.3