From: Martin KaFai Lau <kafai@fb.com>
To: <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>, <kernel-team@fb.com>,
<netdev@vger.kernel.org>, Andrii Nakryiko <andrii@kernel.org>
Subject: [PATCH v2 bpf-next 10/14] libbpf: Record extern sym relocation first
Date: Wed, 24 Mar 2021 18:52:27 -0700 [thread overview]
Message-ID: <20210325015227.1548623-1-kafai@fb.com> (raw)
In-Reply-To: <20210325015124.1543397-1-kafai@fb.com>
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.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
---
tools/lib/bpf/libbpf.c | 63 +++++++++++++++++++++++-------------------
1 file changed, 34 insertions(+), 29 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 1a2dbde19b7e..23148566ab3a 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
@@ -3407,31 +3412,7 @@ 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;
@@ -3460,6 +3441,30 @@ 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);
@@ -5699,7 +5704,7 @@ static int bpf_core_patch_insn(struct bpf_program *prog,
/* 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;
@@ -5775,7 +5780,7 @@ static int bpf_core_patch_insn(struct bpf_program *prog,
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 ||
--
2.30.2
next prev parent reply other threads:[~2021-03-25 1:53 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-25 1:51 [PATCH v2 bpf-next 00/14] bpf: Support calling kernel function Martin KaFai Lau
2021-03-25 1:51 ` [PATCH v2 bpf-next 01/14] bpf: Simplify freeing logic in linfo and jited_linfo Martin KaFai Lau
2021-03-25 1:51 ` [PATCH v2 bpf-next 02/14] bpf: Refactor btf_check_func_arg_match Martin KaFai Lau
2021-03-25 1:51 ` [PATCH v2 bpf-next 03/14] bpf: Support bpf program calling kernel function Martin KaFai Lau
2021-03-25 22:02 ` Toke Høiland-Jørgensen
2021-03-25 23:09 ` Martin KaFai Lau
2021-03-26 10:11 ` Toke Høiland-Jørgensen
2021-03-26 14:20 ` Alexei Starovoitov
2021-03-26 15:14 ` Toke Høiland-Jørgensen
2021-03-27 3:59 ` Alexei Starovoitov
2021-03-25 1:51 ` [PATCH v2 bpf-next 04/14] bpf: Support kernel function call in x86-32 Martin KaFai Lau
2021-03-25 1:51 ` [PATCH v2 bpf-next 05/14] tcp: Rename bictcp function prefix to cubictcp Martin KaFai Lau
2021-03-25 1:52 ` [PATCH v2 bpf-next 06/14] bpf: tcp: Put some tcp cong functions in allowlist for bpf-tcp-cc Martin KaFai Lau
2021-03-25 1:52 ` [PATCH v2 bpf-next 07/14] libbpf: Refactor bpf_object__resolve_ksyms_btf_id Martin KaFai Lau
2021-03-25 1:52 ` [PATCH v2 bpf-next 08/14] libbpf: Refactor codes for finding btf id of a kernel symbol Martin KaFai Lau
2021-03-25 1:52 ` [PATCH v2 bpf-next 09/14] libbpf: Rename RELO_EXTERN to RELO_EXTERN_VAR Martin KaFai Lau
2021-03-25 1:52 ` Martin KaFai Lau [this message]
2021-03-25 1:52 ` [PATCH v2 bpf-next 11/14] libbpf: Support extern kernel function Martin KaFai Lau
2021-03-25 1:52 ` [PATCH v2 bpf-next 12/14] bpf: selftests: Rename bictcp to bpf_cubic Martin KaFai Lau
2021-03-25 1:52 ` [PATCH v2 bpf-next 13/14] bpf: selftests: bpf_cubic and bpf_dctcp calling kernel functions Martin KaFai Lau
2021-03-25 1:52 ` [PATCH v2 bpf-next 14/14] bpf: selftests: Add kfunc_call test Martin KaFai Lau
2021-03-27 3:50 ` [PATCH v2 bpf-next 00/14] bpf: Support calling kernel function patchwork-bot+netdevbpf
2021-03-27 21:25 ` Cong Wang
2021-03-27 21:28 ` Alexei Starovoitov
2021-03-27 22:07 ` Cong Wang
2021-03-27 22:53 ` Alexei Starovoitov
2021-03-28 20:13 ` Cong Wang
2021-03-29 1:24 ` Martin KaFai Lau
2021-03-29 16:06 ` Lorenz Bauer
2021-03-29 19:08 ` Martin KaFai Lau
2021-03-31 6:44 ` Andrii Nakryiko
2021-04-01 19:51 ` Martin KaFai Lau
2021-04-01 19:52 ` Andrii Nakryiko
2021-03-29 20:18 ` Cong Wang
2021-03-30 9:43 ` Lorenz Bauer
2021-03-30 14:35 ` Alexei Starovoitov
2021-03-30 19:58 ` Cong Wang
2021-03-30 21:43 ` Martin KaFai Lau
2021-03-31 3:28 ` [External] " Jiang Wang .
2021-03-31 4:55 ` Martin KaFai Lau
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