objtool/LoongArch: Implement instruction decoder

Only copy the minimal definitions of instruction opcodes and formats
in inst.h from arch/loongarch to tools/arch/loongarch, and also copy
the definition of sign_extend64() to tools/include/linux/bitops.h to
decode the following kinds of instructions:

(1) stack pointer related instructions
addi.d, ld.d, st.d, ldptr.d and stptr.d

(2) branch and jump related instructions
beq, bne, blt, bge, bltu, bgeu, beqz, bnez, bceqz, bcnez, b, bl and jirl

(3) other instructions
break, nop and ertn

See more info about instructions in LoongArch Reference Manual:
https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html

Co-developed-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Co-developed-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Youling Tang <tangyouling@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

1 files changed, 161 insertions, 0 deletions

diff --git a/tools/arch/loongarch/include/asm/inst.h b/tools/arch/loongarch/include/asm/inst.h
new file mode 100644
index 000000000000..c25b5853181d
--- /dev/null
+++ b/tools/arch/loongarch/include/asm/inst.h
@@ -0,0 +1,161 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_INST_H
+#define _ASM_INST_H
+
+#include <linux/bitops.h>
+
+#define LOONGARCH_INSN_NOP		0x03400000
+
+enum reg0i15_op {
+	break_op	= 0x54,
+};
+
+enum reg0i26_op {
+	b_op		= 0x14,
+	bl_op		= 0x15,
+};
+
+enum reg1i21_op {
+	beqz_op		= 0x10,
+	bnez_op		= 0x11,
+	bceqz_op	= 0x12, /* bits[9:8] = 0x00 */
+	bcnez_op	= 0x12, /* bits[9:8] = 0x01 */
+};
+
+enum reg2_op {
+	ertn_op		= 0x1920e,
+};
+
+enum reg2i12_op {
+	addid_op	= 0x0b,
+	andi_op		= 0x0d,
+	ldd_op		= 0xa3,
+	std_op		= 0xa7,
+};
+
+enum reg2i14_op {
+	ldptrd_op	= 0x26,
+	stptrd_op	= 0x27,
+};
+
+enum reg2i16_op {
+	jirl_op		= 0x13,
+	beq_op		= 0x16,
+	bne_op		= 0x17,
+	blt_op		= 0x18,
+	bge_op		= 0x19,
+	bltu_op		= 0x1a,
+	bgeu_op		= 0x1b,
+};
+
+struct reg0i15_format {
+	unsigned int immediate : 15;
+	unsigned int opcode : 17;
+};
+
+struct reg0i26_format {
+	unsigned int immediate_h : 10;
+	unsigned int immediate_l : 16;
+	unsigned int opcode : 6;
+};
+
+struct reg1i21_format {
+	unsigned int immediate_h  : 5;
+	unsigned int rj : 5;
+	unsigned int immediate_l : 16;
+	unsigned int opcode : 6;
+};
+
+struct reg2_format {
+	unsigned int rd : 5;
+	unsigned int rj : 5;
+	unsigned int opcode : 22;
+};
+
+struct reg2i12_format {
+	unsigned int rd : 5;
+	unsigned int rj : 5;
+	unsigned int immediate : 12;
+	unsigned int opcode : 10;
+};
+
+struct reg2i14_format {
+	unsigned int rd : 5;
+	unsigned int rj : 5;
+	unsigned int immediate : 14;
+	unsigned int opcode : 8;
+};
+
+struct reg2i16_format {
+	unsigned int rd : 5;
+	unsigned int rj : 5;
+	unsigned int immediate : 16;
+	unsigned int opcode : 6;
+};
+
+union loongarch_instruction {
+	unsigned int word;
+	struct reg0i15_format	reg0i15_format;
+	struct reg0i26_format	reg0i26_format;
+	struct reg1i21_format	reg1i21_format;
+	struct reg2_format	reg2_format;
+	struct reg2i12_format	reg2i12_format;
+	struct reg2i14_format	reg2i14_format;
+	struct reg2i16_format	reg2i16_format;
+};
+
+#define LOONGARCH_INSN_SIZE	sizeof(union loongarch_instruction)
+
+enum loongarch_gpr {
+	LOONGARCH_GPR_ZERO = 0,
+	LOONGARCH_GPR_RA = 1,
+	LOONGARCH_GPR_TP = 2,
+	LOONGARCH_GPR_SP = 3,
+	LOONGARCH_GPR_A0 = 4,	/* Reused as V0 for return value */
+	LOONGARCH_GPR_A1,	/* Reused as V1 for return value */
+	LOONGARCH_GPR_A2,
+	LOONGARCH_GPR_A3,
+	LOONGARCH_GPR_A4,
+	LOONGARCH_GPR_A5,
+	LOONGARCH_GPR_A6,
+	LOONGARCH_GPR_A7,
+	LOONGARCH_GPR_T0 = 12,
+	LOONGARCH_GPR_T1,
+	LOONGARCH_GPR_T2,
+	LOONGARCH_GPR_T3,
+	LOONGARCH_GPR_T4,
+	LOONGARCH_GPR_T5,
+	LOONGARCH_GPR_T6,
+	LOONGARCH_GPR_T7,
+	LOONGARCH_GPR_T8,
+	LOONGARCH_GPR_FP = 22,
+	LOONGARCH_GPR_S0 = 23,
+	LOONGARCH_GPR_S1,
+	LOONGARCH_GPR_S2,
+	LOONGARCH_GPR_S3,
+	LOONGARCH_GPR_S4,
+	LOONGARCH_GPR_S5,
+	LOONGARCH_GPR_S6,
+	LOONGARCH_GPR_S7,
+	LOONGARCH_GPR_S8,
+	LOONGARCH_GPR_MAX
+};
+
+#define DEF_EMIT_REG2I16_FORMAT(NAME, OP)				\
+static inline void emit_##NAME(union loongarch_instruction *insn,	\
+			       enum loongarch_gpr rj,			\
+			       enum loongarch_gpr rd,			\
+			       int offset)				\
+{									\
+	insn->reg2i16_format.opcode = OP;				\
+	insn->reg2i16_format.immediate = offset;			\
+	insn->reg2i16_format.rj = rj;					\
+	insn->reg2i16_format.rd = rd;					\
+}
+
+DEF_EMIT_REG2I16_FORMAT(jirl, jirl_op)
+
+#endif /* _ASM_INST_H */