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Commit 56cbd82e authored by Jiong Wang's avatar Jiong Wang Committed by Alexei Starovoitov
Browse files

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: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: default avatarJiong Wang <jiong.wang@netronome.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 092ed096

kernel/bpf/disasm.c

+19 −15
Original line number Diff line number Diff line
@@ -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);

		}