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authorMartin KaFai Lau <kafai@fb.com>2021-03-25 02:52:27 +0100
committerAlexei Starovoitov <ast@kernel.org>2021-03-27 04:41:51 +0100
commitaa0b8d43e9537d371cbd3f272d3403f2b15201af (patch)
treecce5b4309f5669bf16a6cf4be613d44a535ab615 /tools/lib
parentlibbpf: Rename RELO_EXTERN to RELO_EXTERN_VAR (diff)
downloadlinux-aa0b8d43e9537d371cbd3f272d3403f2b15201af.tar.xz
linux-aa0b8d43e9537d371cbd3f272d3403f2b15201af.zip
libbpf: Record extern sym relocation first
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. is_call_insn() helper is added. The existing is_ldimm64() helper is renamed to is_ldimm64_insn() for consistency. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210325015227.1548623-1-kafai@fb.com
Diffstat (limited to 'tools/lib')
-rw-r--r--tools/lib/bpf/libbpf.c63
1 files changed, 34 insertions, 29 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 0ac53dce37b7..e1615c274250 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -573,14 +573,19 @@ static bool insn_is_subprog_call(const struct bpf_insn *insn)
insn->off == 0;
}
-static bool is_ldimm64(struct bpf_insn *insn)
+static bool is_ldimm64_insn(struct bpf_insn *insn)
{
return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
}
+static bool is_call_insn(const struct bpf_insn *insn)
+{
+ return insn->code == (BPF_JMP | BPF_CALL);
+}
+
static bool insn_is_pseudo_func(struct bpf_insn *insn)
{
- return is_ldimm64(insn) && insn->src_reg == BPF_PSEUDO_FUNC;
+ return is_ldimm64_insn(insn) && insn->src_reg == BPF_PSEUDO_FUNC;
}
static int
@@ -3408,31 +3413,7 @@ 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 (!is_call_insn(insn) && !is_ldimm64_insn(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;
@@ -3461,6 +3442,30 @@ static int bpf_program__record_reloc(struct bpf_program *prog,
return 0;
}
+ /* sub-program call relocation */
+ if (is_call_insn(insn)) {
+ 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);
@@ -5700,7 +5705,7 @@ poison:
/* poison second part of ldimm64 to avoid confusing error from
* verifier about "unknown opcode 00"
*/
- if (is_ldimm64(insn))
+ if (is_ldimm64_insn(insn))
bpf_core_poison_insn(prog, relo_idx, insn_idx + 1, insn + 1);
bpf_core_poison_insn(prog, relo_idx, insn_idx, insn);
return 0;
@@ -5776,7 +5781,7 @@ poison:
case BPF_LD: {
__u64 imm;
- if (!is_ldimm64(insn) ||
+ if (!is_ldimm64_insn(insn) ||
insn[0].src_reg != 0 || insn[0].off != 0 ||
insn_idx + 1 >= prog->insns_cnt ||
insn[1].code != 0 || insn[1].dst_reg != 0 ||