When debugging converted (and other) programs it is useful
to see disassembled eBPF output.
Signed-off-by: Stephen Hemminger <step...@networkplumber.org>
---
lib/bpf/bpf_dump.c | 118 ++++++++++++++++++++++++++++++++++++++++++++
lib/bpf/meson.build | 1 +
lib/bpf/rte_bpf.h | 14 ++++++
lib/bpf/version.map | 1 +
4 files changed, 134 insertions(+)
create mode 100644 lib/bpf/bpf_dump.c
diff --git a/lib/bpf/bpf_dump.c b/lib/bpf/bpf_dump.c
new file mode 100644
index 000000000000..a6a431e64903
--- /dev/null
+++ b/lib/bpf/bpf_dump.c
@@ -0,0 +1,118 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright (c) 2021 Stephen Hemminger
+ * Based on filter2xdp
+ * Copyright (C) 2017 Tobias Klauser
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+
+#include "rte_bpf.h"
+
+#define BPF_OP_INDEX(x) (BPF_OP(x) >> 4)
+#define BPF_SIZE_INDEX(x) (BPF_SIZE(x) >> 3)
+
+static const char *const class_tbl[] = {
+ [BPF_LD] = "ld", [BPF_LDX] = "ldx", [BPF_ST] = "st",
+ [BPF_STX] = "stx", [BPF_ALU] = "alu", [BPF_JMP] = "jmp",
+ [BPF_RET] = "ret", [BPF_MISC] = "alu64",
+};
+
+static const char *const alu_op_tbl[16] = {
+ [BPF_ADD >> 4] = "add", [BPF_SUB >> 4] = "sub",
+ [BPF_MUL >> 4] = "mul", [BPF_DIV >> 4] = "div",
+ [BPF_OR >> 4] = "or", [BPF_AND >> 4] = "and",
+ [BPF_LSH >> 4] = "lsh", [BPF_RSH >> 4] = "rsh",
+ [BPF_NEG >> 4] = "neg", [BPF_MOD >> 4] = "mod",
+ [BPF_XOR >> 4] = "xor", [EBPF_MOV >> 4] = "mov",
+ [EBPF_ARSH >> 4] = "arsh", [EBPF_END >> 4] = "endian",
+};
+
+static const char *const size_tbl[] = {
+ [BPF_W >> 3] = "w",
+ [BPF_H >> 3] = "h",
+ [BPF_B >> 3] = "b",
+ [EBPF_DW >> 3] = "dw",
+};
+
+static const char *const jump_tbl[16] = {
+ [BPF_JA >> 4] = "ja", [BPF_JEQ >> 4] = "jeq",
+ [BPF_JGT >> 4] = "jgt", [BPF_JGE >> 4] = "jge",
+ [BPF_JSET >> 4] = "jset", [EBPF_JNE >> 4] = "jne",
+ [EBPF_JSGT >> 4] = "jsgt", [EBPF_JSGE >> 4] = "jsge",
+ [EBPF_CALL >> 4] = "call", [EBPF_EXIT >> 4] = "exit",
+};
+
+static void ebpf_dump(FILE *f, const struct ebpf_insn insn, size_t n)
+{
+ const char *op, *postfix = "";
+ uint8_t cls = BPF_CLASS(insn.code);
+
+ fprintf(f, " L%zu:\t", n);
+
+ switch (cls) {
+ default:
+ fprintf(f, "unimp 0x%x // class: %s\n", insn.code,
+ class_tbl[cls]);
+ break;
+ case BPF_ALU:
+ postfix = "32";
+ /* fall through */
+ case EBPF_ALU64:
+ op = alu_op_tbl[BPF_OP_INDEX(insn.code)];
+ if (BPF_SRC(insn.code) == BPF_X)
+ fprintf(f, "%s%s r%u, r%u\n", op, postfix, insn.dst_reg,
+ insn.src_reg);
+ else
+ fprintf(f, "%s%s r%u, #0x%x\n", op, postfix,
+ insn.dst_reg, insn.imm);
+ break;
+ case BPF_LD:
+ op = "ld";
+ postfix = size_tbl[BPF_SIZE_INDEX(insn.code)];
+ if (BPF_MODE(insn.code) == BPF_IMM)
+ fprintf(f, "%s%s r%d, #0x%x\n", op, postfix,
+ insn.dst_reg, insn.imm);
+ else if (BPF_MODE(insn.code) == BPF_ABS)
+ fprintf(f, "%s%s r%d, [%d]\n", op, postfix,
+ insn.dst_reg, insn.imm);
+ else if (BPF_MODE(insn.code) == BPF_IND)
+ fprintf(f, "%s%s r%d, [r%u + %d]\n", op, postfix,
+ insn.dst_reg, insn.src_reg, insn.imm);
+ else
+ fprintf(f, "// BUG: LD opcode 0x%02x in eBPF insns\n",
+ insn.code);
+ break;
+ case BPF_LDX:
+ op = "ldx";
+ postfix = size_tbl[BPF_SIZE_INDEX(insn.code)];
+ fprintf(f, "%s%s r%d, [r%u + %d]\n", op, postfix, insn.dst_reg,
+ insn.src_reg, insn.off);
+ break;
+#define L(pc, off) ((int)(pc) + 1 + (off))
+ case BPF_JMP:
+ op = jump_tbl[BPF_OP_INDEX(insn.code)];
+ if (op == NULL)
+ fprintf(f, "invalid jump opcode: %#x\n", insn.code);
+ else if (BPF_OP(insn.code) == BPF_JA)
+ fprintf(f, "%s L%d\n", op, L(n, insn.off));
+ else if (BPF_OP(insn.code) == EBPF_EXIT)
+ fprintf(f, "%s\n", op);
+ else
+ fprintf(f, "%s r%u, #0x%x, L%d\n", op, insn.dst_reg,
+ insn.imm, L(n, insn.off));
+ break;
+ case BPF_RET:
+ fprintf(f, "// BUG: RET opcode 0x%02x in eBPF insns\n",
+ insn.code);
+ break;
+ }
+}
+
+void rte_bpf_dump(FILE *f, const struct ebpf_insn *buf, uint32_t len)
+{
+ uint32_t i;
+
+ for (i = 0; i < len; ++i)
+ ebpf_dump(f, buf[i], i);
+}
diff --git a/lib/bpf/meson.build b/lib/bpf/meson.build
index 54f7610ae990..5b5585173aeb 100644
--- a/lib/bpf/meson.build
+++ b/lib/bpf/meson.build
@@ -2,6 +2,7 @@
# Copyright(c) 2018 Intel Corporation
sources = files('bpf.c',
+ 'bpf_dump.c',
'bpf_exec.c',
'bpf_load.c',
'bpf_pkt.c',
diff --git a/lib/bpf/rte_bpf.h b/lib/bpf/rte_bpf.h
index 2f23e272a376..0d0a84b130a0 100644
--- a/lib/bpf/rte_bpf.h
+++ b/lib/bpf/rte_bpf.h
@@ -198,6 +198,20 @@ rte_bpf_exec_burst(const struct rte_bpf *bpf, void *ctx[],
uint64_t rc[],
int
rte_bpf_get_jit(const struct rte_bpf *bpf, struct rte_bpf_jit *jit);
+/**
+ * Dump epf instructions to a file.
+ *
+ * @param f
+ * A pointer to a file for output
+ * @param buf
+ * A pointer to BPF instructions
+ * @param len
+ * Number of BPF instructions to dump.
+ */
+__rte_experimental
+void
+rte_bpf_dump(FILE *f, const struct ebpf_insn *buf, uint32_t len);
+
#ifdef RTE_PORT_PCAP
struct bpf_program;
diff --git a/lib/bpf/version.map b/lib/bpf/version.map
index 47082d5003ef..3b953f2f4592 100644
--- a/lib/bpf/version.map
+++ b/lib/bpf/version.map
@@ -19,4 +19,5 @@ EXPERIMENTAL {
global:
rte_bpf_convert;
+ rte_bpf_dump;
};
--
2.30.2
