LoongArch: Add larch_insn_gen_break() to generate break insns

There exist various break insns such as BRK_KPROBE_BP, BRK_KPROBE_SSTEPBP,
BRK_UPROBE_BP and BRK_UPROBE_XOLBP, add larch_insn_gen_break() to generate
break insns simpler, this is preparation for later patch.

Tested-by: Jeff Xie <xiehuan09@gmail.com>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/include/asm/inst.h

@@ -482,6 +482,8 @@ u32 larch_insn_gen_nop(void);
 u32 larch_insn_gen_b(unsigned long pc, unsigned long dest);
 u32 larch_insn_gen_bl(unsigned long pc, unsigned long dest);
 
+u32 larch_insn_gen_break(int imm);
+
 u32 larch_insn_gen_or(enum loongarch_gpr rd, enum loongarch_gpr rj, enum loongarch_gpr rk);
 u32 larch_insn_gen_move(enum loongarch_gpr rd, enum loongarch_gpr rj);
 
@@ -500,6 +502,16 @@ static inline bool unsigned_imm_check(unsigned long val, unsigned int bit)
 	return val < (1UL << bit);
 }
 
+#define DEF_EMIT_REG0I15_FORMAT(NAME, OP)				\
+static inline void emit_##NAME(union loongarch_instruction *insn,	\
+			       int imm)					\
+{									\
+	insn->reg0i15_format.opcode = OP;				\
+	insn->reg0i15_format.immediate = imm;				\
+}
+
+DEF_EMIT_REG0I15_FORMAT(break, break_op)
+
 #define DEF_EMIT_REG0I26_FORMAT(NAME, OP)				\
 static inline void emit_##NAME(union loongarch_instruction *insn,	\
 			       int offset)				\

arch/loongarch/kernel/inst.c

@@ -253,6 +253,20 @@ u32 larch_insn_gen_bl(unsigned long pc, unsigned long dest)
 	return insn.word;
 }
 
+u32 larch_insn_gen_break(int imm)
+{
+	union loongarch_instruction insn;
+
+	if (imm < 0 || imm >= SZ_32K) {
+		pr_warn("The generated break instruction is out of range.\n");
+		return INSN_BREAK;
+	}
+
+	emit_break(&insn, imm);
+
+	return insn.word;
+}
+
 u32 larch_insn_gen_or(enum loongarch_gpr rd, enum loongarch_gpr rj, enum loongarch_gpr rk)
 {
 	union loongarch_instruction insn;