On 16/6/26 12:23, Alexei Starovoitov wrote: > On Mon, Jun 15, 2026 at 9:19 PM Leon Hwang <[email protected]> wrote: >> >> On 16/6/26 05:29, Alexei Starovoitov wrote: >>> On Mon Jun 15, 2026 at 8:26 AM PDT, Leon Hwang wrote: >> [...] >>>> + 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 was to check the 'off' and the mov64_percpu_reg insn. >> >> To avoid relying on the insns loaded from ELF obj, use raw insns to >> check the 'off' with a percpu_array map: >> >> struct bpf_insn raw_insns[] = { >> BPF_LD_MAP_VALUE(BPF_REG_1, 0, 0), >> BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, 0), >> BPF_EXIT_INSN(), >> }; >> >> skel = test_global_percpu_data__open_and_load(); >> exp_off = offsetof(struct test_global_percpu_data__percpu, >> struct_data.nums[6]); >> raw_insns[0].imm = bpf_map__fd(skel->maps.percpu); >> raw_insns[1].imm = exp_off; >> >> prog_fd = bpf_prog_load(...); >> err = get_xlated_program(prog_fd, &insns, &cnt); >> idx = find_percpu_ld_imm64(insns, cnt); >> >> ASSERT_EQ(insns[idx + 1].imm, exp_off, "exp_off"); >> >> Would this achieve that goal? > > Hmm. There is nothing like that in the patch. > What are you talking about? > Some future improvement to the patch?
It is future improvement to the patch. Sorry, it is too far from the patch. > My question was about the patch you posted. > What was the point of it? The point of the patch was to check that percpu_array_map_direct_value_meta() computes 'off' correctly against the 'off' encoded in ELF obj, and a mov64_percpu_reg insn should be added after loading the prog. Thanks, Leon
