Fix issues with rte_bpf_dump not supporting or printing incorrectly some instructions that lib/bpf supports, and add warnings when it doesn't:
* Conditional jump with condition between two registers was incorrectly printed by rte_bpf_dump as one with condition between register and immediate. Add missing handling of BPF_X flag. * Call instruction was printed by rte_bpf_dump as conditional jump. Add explicit handling for it. * We only support stx and ldx instructions in BPF_MEM mode, but were not checking the mode in rte_bpf_dump. Check for mode and only print mnemonic if the mode is BPF_MEM, otherwise print an error. * Atomic instructions were not previously supported by rte_bpf_dump. Add necessary handling. * Some instructions have variations with previously unused src_reg or offset fields set to non-zero value. We do not support any of these variations yet, and were printing them as a standard instruction. Print small note after such instructions warning the user that this is a variation. Signed-off-by: Marat Khalili <[email protected]> --- lib/bpf/bpf_dump.c | 69 ++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 57 insertions(+), 12 deletions(-) diff --git a/lib/bpf/bpf_dump.c b/lib/bpf/bpf_dump.c index 6ee0e32b43..91bc7c0a7a 100644 --- a/lib/bpf/bpf_dump.c +++ b/lib/bpf/bpf_dump.c @@ -44,6 +44,19 @@ static const char *const jump_tbl[16] = { [EBPF_CALL >> 4] = "call", [EBPF_EXIT >> 4] = "exit", }; +static inline const char * +atomic_op(int32_t imm) +{ + switch (imm) { + case BPF_ATOMIC_ADD: + return "xadd"; + case BPF_ATOMIC_XCHG: + return "xchg"; + default: + return NULL; + } +} + RTE_EXPORT_SYMBOL(rte_bpf_dump) void rte_bpf_dump(FILE *f, const struct ebpf_insn *buf, uint32_t len) { @@ -52,7 +65,7 @@ void rte_bpf_dump(FILE *f, const struct ebpf_insn *buf, uint32_t len) for (i = 0; i < len; ++i) { const struct ebpf_insn *ins = buf + i; uint8_t cls = BPF_CLASS(ins->code); - const char *op, *postfix = ""; + const char *op, *postfix = "", *warning = ""; fprintf(f, " L%u:\t", i); @@ -66,12 +79,15 @@ void rte_bpf_dump(FILE *f, const struct ebpf_insn *buf, uint32_t len) /* fall through */ case EBPF_ALU64: op = alu_op_tbl[BPF_OP_INDEX(ins->code)]; + if (ins->off != 0) + /* Not yet supported variation with non-zero offset. */ + warning = ", off != 0"; if (BPF_SRC(ins->code) == BPF_X) - fprintf(f, "%s%s r%u, r%u\n", op, postfix, ins->dst_reg, - ins->src_reg); + fprintf(f, "%s%s r%u, r%u%s\n", op, postfix, ins->dst_reg, + ins->src_reg, warning); else - fprintf(f, "%s%s r%u, #0x%x\n", op, postfix, - ins->dst_reg, ins->imm); + fprintf(f, "%s%s r%u, #0x%x%s\n", op, postfix, + ins->dst_reg, ins->imm, warning); break; case BPF_LD: op = "ld"; @@ -79,10 +95,13 @@ void rte_bpf_dump(FILE *f, const struct ebpf_insn *buf, uint32_t len) if (ins->code == (BPF_LD | BPF_IMM | EBPF_DW)) { uint64_t val; + if (ins->src_reg != 0) + /* Not yet supported variation with non-zero src. */ + warning = ", src != 0"; 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); + fprintf(f, "%s%s r%d, #0x%"PRIx64"%s\n", + op, postfix, ins->dst_reg, val, warning); i++; } else if (BPF_MODE(ins->code) == BPF_IMM) fprintf(f, "%s%s r%d, #0x%x\n", op, postfix, @@ -100,8 +119,12 @@ void rte_bpf_dump(FILE *f, const struct ebpf_insn *buf, uint32_t len) 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); + if (BPF_MODE(ins->code) == BPF_MEM) + fprintf(f, "%s%s r%d, [r%u + %d]\n", op, postfix, ins->dst_reg, + ins->src_reg, ins->off); + else + fprintf(f, "// BUG: LDX opcode 0x%02x in eBPF insns\n", + ins->code); break; case BPF_ST: op = "st"; @@ -114,7 +137,20 @@ void rte_bpf_dump(FILE *f, const struct ebpf_insn *buf, uint32_t len) ins->code); break; case BPF_STX: - op = "stx"; + if (BPF_MODE(ins->code) == BPF_MEM) + op = "stx"; + else if (BPF_MODE(ins->code) == EBPF_ATOMIC) { + op = atomic_op(ins->imm); + if (op == NULL) { + fprintf(f, "// BUG: ATOMIC operation 0x%x in eBPF insns\n", + ins->imm); + break; + } + } else { + fprintf(f, "// BUG: STX opcode 0x%02x in eBPF insns\n", + ins->code); + break; + } 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); @@ -122,12 +158,21 @@ void rte_bpf_dump(FILE *f, const struct ebpf_insn *buf, uint32_t len) #define L(pc, off) ((int)(pc) + 1 + (off)) case BPF_JMP: op = jump_tbl[BPF_OP_INDEX(ins->code)]; + if (ins->src_reg != 0) + /* Not yet supported variation with non-zero src w/o condition. */ + warning = ", src != 0"; 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)); + fprintf(f, "%s L%d%s\n", op, L(i, ins->off), warning); + else if (BPF_OP(ins->code) == EBPF_CALL) + /* Call of helper function with index in immediate. */ + fprintf(f, "%s #%u%s\n", op, ins->imm, warning); else if (BPF_OP(ins->code) == EBPF_EXIT) - fprintf(f, "%s\n", op); + fprintf(f, "%s%s\n", op, warning); + else if (BPF_SRC(ins->code) == BPF_X) + fprintf(f, "%s r%u, r%u, L%d\n", op, ins->dst_reg, + ins->src_reg, L(i, ins->off)); else fprintf(f, "%s r%u, #0x%x, L%d\n", op, ins->dst_reg, ins->imm, L(i, ins->off)); -- 2.43.0
