bpf: disassembler support JMP32

This patch teaches disassembler about JMP32. There are two places to
update:

  - Class 0x6 now used by BPF_JMP32, not "unused".

  - BPF_JMP32 need to show comparison operands properly.
    The disassemble format is to add an extra "(32)" before the operands if
    it is a sub-register. A better disassemble format for both JMP32 and
    ALU32 just show the register prefix as "w" instead of "r", this is the
    format using by LLVM assembler.

Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/kernel/bpf/disasm.c b/kernel/bpf/disasm.c
index d6b7637..de73f55 100644 (file)
--- a/kernel/bpf/disasm.c
+++ b/kernel/bpf/disasm.c
@@ -67,7 +67,7 @@ const char *const bpf_class_string[8] = {
        [BPF_STX]   = "stx",
        [BPF_ALU]   = "alu",
        [BPF_JMP]   = "jmp",
-       [BPF_RET]   = "BUG",
+       [BPF_JMP32] = "jmp32",
        [BPF_ALU64] = "alu64",
 };
 
@@ -136,23 +136,22 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs,
                        else
                                print_bpf_end_insn(verbose, cbs->private_data, insn);
                } else if (BPF_OP(insn->code) == BPF_NEG) {
-                       verbose(cbs->private_data, "(%02x) r%d = %s-r%d\n",
-                               insn->code, insn->dst_reg,
-                               class == BPF_ALU ? "(u32) " : "",
+                       verbose(cbs->private_data, "(%02x) %c%d = -%c%d\n",
+                               insn->code, class == BPF_ALU ? 'w' : 'r',
+                               insn->dst_reg, class == BPF_ALU ? 'w' : 'r',
                                insn->dst_reg);
                } else if (BPF_SRC(insn->code) == BPF_X) {
-                       verbose(cbs->private_data, "(%02x) %sr%d %s %sr%d\n",
-                               insn->code, class == BPF_ALU ? "(u32) " : "",
+                       verbose(cbs->private_data, "(%02x) %c%d %s %c%d\n",
+                               insn->code, class == BPF_ALU ? 'w' : 'r',
                                insn->dst_reg,
                                bpf_alu_string[BPF_OP(insn->code) >> 4],
-                               class == BPF_ALU ? "(u32) " : "",
+                               class == BPF_ALU ? 'w' : 'r',
                                insn->src_reg);
                } else {
-                       verbose(cbs->private_data, "(%02x) %sr%d %s %s%d\n",
-                               insn->code, class == BPF_ALU ? "(u32) " : "",
+                       verbose(cbs->private_data, "(%02x) %c%d %s %d\n",
+                               insn->code, class == BPF_ALU ? 'w' : 'r',
                                insn->dst_reg,
                                bpf_alu_string[BPF_OP(insn->code) >> 4],
-                               class == BPF_ALU ? "(u32) " : "",
                                insn->imm);
                }
        } else if (class == BPF_STX) {
@@ -220,7 +219,7 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs,
                        verbose(cbs->private_data, "BUG_ld_%02x\n", insn->code);
                        return;
                }
-       } else if (class == BPF_JMP) {
+       } else if (class == BPF_JMP32 || class == BPF_JMP) {
                u8 opcode = BPF_OP(insn->code);
 
                if (opcode == BPF_CALL) {
@@ -244,13 +243,18 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs,
                } else if (insn->code == (BPF_JMP | BPF_EXIT)) {
                        verbose(cbs->private_data, "(%02x) exit\n", insn->code);
                } else if (BPF_SRC(insn->code) == BPF_X) {
-                       verbose(cbs->private_data, "(%02x) if r%d %s r%d goto pc%+d\n",
-                               insn->code, insn->dst_reg,
+                       verbose(cbs->private_data,
+                               "(%02x) if %c%d %s %c%d goto pc%+d\n",
+                               insn->code, class == BPF_JMP32 ? 'w' : 'r',
+                               insn->dst_reg,
                                bpf_jmp_string[BPF_OP(insn->code) >> 4],
+                               class == BPF_JMP32 ? 'w' : 'r',
                                insn->src_reg, insn->off);
                } else {
-                       verbose(cbs->private_data, "(%02x) if r%d %s 0x%x goto pc%+d\n",
-                               insn->code, insn->dst_reg,
+                       verbose(cbs->private_data,
+                               "(%02x) if %c%d %s 0x%x goto pc%+d\n",
+                               insn->code, class == BPF_JMP32 ? 'w' : 'r',
+                               insn->dst_reg,
                                bpf_jmp_string[BPF_OP(insn->code) >> 4],
                                insn->imm, insn->off);
                }