From 745b7587f9e52a4df2121d7214346853b4baf5ed Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Wed, 20 Oct 2021 14:42:29 -0700 Subject: [PATCH] bpf: add function to dump eBPF instructions When debugging converted (and other) programs it is useful to see disassembled eBPF output. Signed-off-by: Stephen Hemminger Acked-by: Konstantin Ananyev Acked-by: Ray Kinsella --- lib/bpf/bpf_dump.c | 139 ++++++++++++++++++++++++++++++++++++++++++++ lib/bpf/meson.build | 1 + lib/bpf/rte_bpf.h | 14 +++++ lib/bpf/version.map | 1 + 4 files changed, 155 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 0000000000..b86977b96d --- /dev/null +++ b/lib/bpf/bpf_dump.c @@ -0,0 +1,139 @@ +/* SPDX-License-Identifier: BSD-3-Clause + * Copyright (c) 2021 Stephen Hemminger + * Based on filter2xdp + * Copyright (C) 2017 Tobias Klauser + */ + +#include +#include + +#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", +}; + +void rte_bpf_dump(FILE *f, const struct ebpf_insn *buf, uint32_t len) +{ + uint32_t i; + + for (i = 0; i < len; ++i) { + const struct ebpf_insn *ins = buf + i; + uint8_t cls = BPF_CLASS(ins->code); + const char *op, *postfix = ""; + + fprintf(f, " L%u:\t", i); + + switch (cls) { + default: + fprintf(f, "unimp 0x%x // class: %s\n", + ins->code, class_tbl[cls]); + break; + case BPF_ALU: + postfix = "32"; + /* fall through */ + case EBPF_ALU64: + op = alu_op_tbl[BPF_OP_INDEX(ins->code)]; + if (BPF_SRC(ins->code) == BPF_X) + fprintf(f, "%s%s r%u, r%u\n", op, postfix, ins->dst_reg, + ins->src_reg); + else + fprintf(f, "%s%s r%u, #0x%x\n", op, postfix, + ins->dst_reg, ins->imm); + break; + case BPF_LD: + op = "ld"; + postfix = size_tbl[BPF_SIZE_INDEX(ins->code)]; + if (ins->code == (BPF_LD | BPF_IMM | EBPF_DW)) { + uint64_t val; + + val = (uint32_t)ins[0].imm | + (uint64_t)(uint32_t)ins[1].imm << 32; + fprintf(f, "%s%s r%d, #0x%"PRIx64"\n", + op, postfix, ins->dst_reg, val); + i++; + } else if (BPF_MODE(ins->code) == BPF_IMM) + fprintf(f, "%s%s r%d, #0x%x\n", op, postfix, + ins->dst_reg, ins->imm); + else if (BPF_MODE(ins->code) == BPF_ABS) + fprintf(f, "%s%s r%d, [%d]\n", op, postfix, + ins->dst_reg, ins->imm); + else if (BPF_MODE(ins->code) == BPF_IND) + fprintf(f, "%s%s r%d, [r%u + %d]\n", op, postfix, + ins->dst_reg, ins->src_reg, ins->imm); + else + fprintf(f, "// BUG: LD opcode 0x%02x in eBPF insns\n", + ins->code); + break; + case BPF_LDX: + op = "ldx"; + postfix = size_tbl[BPF_SIZE_INDEX(ins->code)]; + fprintf(f, "%s%s r%d, [r%u + %d]\n", op, postfix, ins->dst_reg, + ins->src_reg, ins->off); + break; + case BPF_ST: + op = "st"; + postfix = size_tbl[BPF_SIZE_INDEX(ins->code)]; + if (BPF_MODE(ins->code) == BPF_MEM) + fprintf(f, "%s%s [r%d + %d], #0x%x\n", op, postfix, + ins->dst_reg, ins->off, ins->imm); + else + fprintf(f, "// BUG: ST opcode 0x%02x in eBPF insns\n", + ins->code); + break; + case BPF_STX: + op = "stx"; + postfix = size_tbl[BPF_SIZE_INDEX(ins->code)]; + fprintf(f, "%s%s [r%d + %d], r%u\n", op, postfix, + ins->dst_reg, ins->off, ins->src_reg); + break; +#define L(pc, off) ((int)(pc) + 1 + (off)) + case BPF_JMP: + op = jump_tbl[BPF_OP_INDEX(ins->code)]; + if (op == NULL) + fprintf(f, "invalid jump opcode: %#x\n", ins->code); + else if (BPF_OP(ins->code) == BPF_JA) + fprintf(f, "%s L%d\n", op, L(i, ins->off)); + else if (BPF_OP(ins->code) == EBPF_EXIT) + fprintf(f, "%s\n", op); + else + fprintf(f, "%s r%u, #0x%x, L%d\n", op, ins->dst_reg, + ins->imm, L(i, ins->off)); + break; + case BPF_RET: + fprintf(f, "// BUG: RET opcode 0x%02x in eBPF insns\n", + ins->code); + break; + } + } +} diff --git a/lib/bpf/meson.build b/lib/bpf/meson.build index 54f7610ae9..07e5494a8c 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 2f23e272a3..0d0a84b130 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 47082d5003..3b953f2f45 100644 --- a/lib/bpf/version.map +++ b/lib/bpf/version.map @@ -19,4 +19,5 @@ EXPERIMENTAL { global: rte_bpf_convert; + rte_bpf_dump; }; -- 2.20.1