On Tue, Mar 16, 2021 at 12:02 AM Martin KaFai Lau <kafai@xxxxxx> wrote:
>
> This patch records the extern sym relocs first before recording
> subprog relocs. The later patch will have relocs for extern
> kernel function call which is also using BPF_JMP | BPF_CALL.
> It will be easier to handle the extern symbols first in
> the later patch.
>
> Signed-off-by: Martin KaFai Lau <kafai@xxxxxx>
> ---
Looks good, just let's add that tiny helper for cleanliness and to
match what we do for ldimm64
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> tools/lib/bpf/libbpf.c | 50 +++++++++++++++++++++---------------------
> 1 file changed, 25 insertions(+), 25 deletions(-)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 8f924aece736..0a60fcb2fba2 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -3416,31 +3416,7 @@ static int bpf_program__record_reloc(struct bpf_program *prog,
>
> reloc_desc->processed = false;
>
> - /* sub-program call relocation */
> - if (insn->code == (BPF_JMP | BPF_CALL)) {
> - if (insn->src_reg != BPF_PSEUDO_CALL) {
> - pr_warn("prog '%s': incorrect bpf_call opcode\n", prog->name);
> - return -LIBBPF_ERRNO__RELOC;
> - }
> - /* text_shndx can be 0, if no default "main" program exists */
> - if (!shdr_idx || shdr_idx != obj->efile.text_shndx) {
> - sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx));
> - pr_warn("prog '%s': bad call relo against '%s' in section '%s'\n",
> - prog->name, sym_name, sym_sec_name);
> - return -LIBBPF_ERRNO__RELOC;
> - }
> - if (sym->st_value % BPF_INSN_SZ) {
> - pr_warn("prog '%s': bad call relo against '%s' at offset %zu\n",
> - prog->name, sym_name, (size_t)sym->st_value);
> - return -LIBBPF_ERRNO__RELOC;
> - }
> - reloc_desc->type = RELO_CALL;
> - reloc_desc->insn_idx = insn_idx;
> - reloc_desc->sym_off = sym->st_value;
> - return 0;
> - }
> -
> - if (!is_ldimm64(insn)) {
> + if (insn->code != (BPF_JMP | BPF_CALL) && !is_ldimm64(insn)) {
> pr_warn("prog '%s': invalid relo against '%s' for insns[%d].code 0x%x\n",
> prog->name, sym_name, insn_idx, insn->code);
> return -LIBBPF_ERRNO__RELOC;
> @@ -3469,6 +3445,30 @@ static int bpf_program__record_reloc(struct bpf_program *prog,
> return 0;
> }
>
> + /* sub-program call relocation */
> + if (insn->code == (BPF_JMP | BPF_CALL)) {
can you please add is_call_insn() helper checking this, similarly to
how we now have is_ldimm64() (should probably be is_ldimm64_insn() for
consistency)
> + if (insn->src_reg != BPF_PSEUDO_CALL) {
> + pr_warn("prog '%s': incorrect bpf_call opcode\n", prog->name);
> + return -LIBBPF_ERRNO__RELOC;
> + }
> + /* text_shndx can be 0, if no default "main" program exists */
> + if (!shdr_idx || shdr_idx != obj->efile.text_shndx) {
> + sym_sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, shdr_idx));
> + pr_warn("prog '%s': bad call relo against '%s' in section '%s'\n",
> + prog->name, sym_name, sym_sec_name);
> + return -LIBBPF_ERRNO__RELOC;
> + }
> + if (sym->st_value % BPF_INSN_SZ) {
> + pr_warn("prog '%s': bad call relo against '%s' at offset %zu\n",
> + prog->name, sym_name, (size_t)sym->st_value);
> + return -LIBBPF_ERRNO__RELOC;
> + }
> + reloc_desc->type = RELO_CALL;
> + reloc_desc->insn_idx = insn_idx;
> + reloc_desc->sym_off = sym->st_value;
> + return 0;
> + }
> +
> if (!shdr_idx || shdr_idx >= SHN_LORESERVE) {
> pr_warn("prog '%s': invalid relo against '%s' in special section 0x%x; forgot to initialize global var?..\n",
> prog->name, sym_name, shdr_idx);
> --
> 2.30.2
>
