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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>
hifive-unleashed-5.1
Jiong Wang 2019-01-26 12:26:02 -05:00 committed by Alexei Starovoitov
parent 092ed0968b
commit 56cbd82ef0
1 changed files with 19 additions and 15 deletions
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34
kernel/bpf/disasm.c
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@ -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);
}