On Mon Jun 15, 2026 at 8:26 AM PDT, Leon Hwang wrote: > Add a test to verify global percpu data related xlated insns: > > 1. ld_imm64: compare xlated one with the one in ELF object file. > 2. mov64_percpu_reg: it is added by verifier. > > Signed-off-by: Leon Hwang <[email protected]> > --- > .../bpf/prog_tests/global_data_init.c | 87 +++++++++++++++++++ > .../bpf/progs/test_global_percpu_data.c | 11 +++ > 2 files changed, 98 insertions(+) > > diff --git a/tools/testing/selftests/bpf/prog_tests/global_data_init.c > b/tools/testing/selftests/bpf/prog_tests/global_data_init.c > index e4c290492ff8..fcc2c4ec8644 100644 > --- a/tools/testing/selftests/bpf/prog_tests/global_data_init.c > +++ b/tools/testing/selftests/bpf/prog_tests/global_data_init.c > @@ -279,6 +279,91 @@ static void test_global_percpu_data_verifier_log(void) > RUN_TESTS(test_global_percpu_data); > } > > +static int find_ld_imm64(const struct bpf_insn *insns, size_t insn_cnt, > struct bpf_insn *ld_imm64) > +{ > + size_t i; > + > + for (i = 0; i < insn_cnt; i++) { > + if (insns[i].code == (BPF_LD | BPF_IMM | BPF_DW)) { > + ld_imm64[0] = insns[i]; > + ld_imm64[1] = insns[i + 1]; > + return i; > + } > + } > + > + return -ENOENT; > +} > + > +/* > + * Special (internal-only) form of mov, used to resolve per-CPU addrs: > + * dst_reg = src_reg + <percpu_base_off> > + * BPF_ADDR_PERCPU is used as a special insn->off value. > + */ > +#define BPF_ADDR_PERCPU (-1) > + > +#define BPF_MOV64_PERCPU_REG(DST, SRC) \ > + ((struct bpf_insn) { \ > + .code = BPF_ALU64 | BPF_MOV | BPF_X, \ > + .dst_reg = DST, \ > + .src_reg = SRC, \ > + .off = BPF_ADDR_PERCPU, \ > + .imm = 0 }) > + > +static __u64 ld_imm64_to_u64(const struct bpf_insn *insn) > +{ > + return ((__u64)(__u32) insn[1].imm << 32) | (__u32) insn[0].imm; > +} > + > +static void test_global_percpu_data_xlated(void) > +{ > + struct bpf_insn ld_imm64_raw[2], ld_imm64_xlated[2], mov64_percpu_reg, > *insns = NULL; > + size_t insn_sz = sizeof(struct bpf_insn); > + struct test_global_percpu_data *skel; > + struct bpf_program *prog; > + int idx, err; > + __u32 cnt; > + > + skel = test_global_percpu_data__open(); > + if (!ASSERT_OK_PTR(skel, "test_global_percpu_data__open")) > + return; > + > + prog = skel->progs.verifier_percpu_read; > + idx = find_ld_imm64(bpf_program__insns(prog), > bpf_program__insn_cnt(prog), ld_imm64_raw); > + if (!ASSERT_GE(idx, 0, "find_ld_imm64 raw")) > + goto out; > + > + err = test_global_percpu_data__load(skel); > + if (!ASSERT_OK(err, "test_global_percpu_data__load")) > + goto out; > + > + err = get_xlated_program(bpf_program__fd(prog), &insns, &cnt); > + if (!ASSERT_OK(err, "get_xlated_program")) > + goto out; > + > + idx = find_ld_imm64(insns, cnt, ld_imm64_xlated); > + if (!ASSERT_GE(idx, 0, "find_ld_imm64 xlated")) > + goto out; > + > + if (!ASSERT_GT(cnt, idx + 2, "xlated insn count")) > + goto out; > + > + ASSERT_EQ(ld_imm64_xlated[0].code, ld_imm64_raw[0].code, "ld_imm64 > opcode"); > + ASSERT_TRUE(ld_imm64_xlated[0].dst_reg == ld_imm64_raw[0].dst_reg, > "ld_imm64 dst_reg"); > + /* > + * The xlated instruction has the map ID in imm and the offset > + * in the next instruction's imm. The raw instruction just has > + * the offset in its imm. > + */ > + ASSERT_EQ(ld_imm64_xlated[1].imm, ld_imm64_to_u64(ld_imm64_raw), > "ld_imm64 off"); > + > + mov64_percpu_reg = BPF_MOV64_PERCPU_REG(ld_imm64_raw[0].dst_reg, > ld_imm64_raw[0].dst_reg); > + ASSERT_MEMEQ(&insns[idx + 2], &mov64_percpu_reg, insn_sz, > "mov64_percpu_reg");
If the point of the test was to check that percpu_array_map_direct_value_meta() computes 'off' correctly then it failed to achieve that goal. It checks that map ID is correct which is a pointless test. Either make it a real test or drop this patch. pw-bot: cr
