[RFC v5 36/57] objtool: arm64: Decode pointer auth load instructions

[Julien Thierry]

Decode load/store instruction provided by the v8.3 pointer
authentication architecture extension.

Suggested-by: Raphael Gault <raphael.gault@xxxxxxx>
Signed-off-by: Julien Thierry <jthierry@xxxxxxxxxx>
---
 tools/objtool/arch/arm64/decode.c             | 51 +++++++++++++++++++
 .../objtool/arch/arm64/include/insn_decode.h  |  3 ++
 2 files changed, 54 insertions(+)

diff --git a/tools/objtool/arch/arm64/decode.c b/tools/objtool/arch/arm64/decode.c
index 1897f62987fa..0bbbacd74e48 100644
--- a/tools/objtool/arch/arm64/decode.c
+++ b/tools/objtool/arch/arm64/decode.c
@@ -885,6 +885,11 @@ static struct aarch64_insn_decoder ld_st_decoder[] = {
 		.value = 0b001100010000010,
 		.decode_func = arm_decode_ld_st_regs_off,
 	},
+	{
+		.mask = 0b001101010000001,
+		.value = 0b001100010000001,
+		.decode_func = arm_decode_ld_st_regs_pac,
+	},
 	{
 		.mask = 0b001101000000000,
 		.value = 0b001101000000000,
@@ -1981,3 +1986,49 @@ int arm_decode_ld_st_regs_pair_pre(u32 instr, enum insn_type *type,
 
 	return 0;
 }
+
+int arm_decode_ld_st_regs_pac(u32 instr, enum insn_type *type,
+			      unsigned long *immediate,
+			      struct list_head *ops_list)
+{
+	unsigned char size = 0, V = 0, W = 0, S = 0;
+	unsigned char rn = 0, rt = 0;
+	struct stack_op *op;
+	u32 imm9 = 0, s10 = 0;
+
+	size = (instr >> 30) & ONES(2);
+	V = EXTRACT_BIT(instr, 26);
+	W = EXTRACT_BIT(instr, 11);
+
+	if (size != 3 || V == 1)
+		return arm_decode_unknown(instr, type, immediate, ops_list);
+
+	rn = (instr >> 5) & ONES(5);
+
+	if (!stack_related_reg(rn)) {
+		*type = INSN_OTHER;
+		return 0;
+	}
+
+	S = EXTRACT_BIT(instr, 22);
+	s10 = (S << 9) | imm9;
+
+	*type = INSN_STACK;
+
+	op = calloc(1, sizeof(*op));
+	list_add_tail(&op->list, ops_list);
+
+	op->dest.reg = rt;
+	op->dest.type = OP_DEST_REG;
+	op->dest.offset = 0;
+	op->src.offset = (SIGN_EXTEND(s10, 9) << 3);
+	if (W) { /* pre-indexed/writeback */
+		op->src.type = OP_SRC_POP;
+		op->src.reg = rn;
+	} else {
+		op->src.type = OP_SRC_REG_INDIRECT;
+		op->src.reg = rn;
+	}
+
+	return 0;
+}
diff --git a/tools/objtool/arch/arm64/include/insn_decode.h b/tools/objtool/arch/arm64/include/insn_decode.h
index 89488c5df5e9..d819d2e795a3 100644
--- a/tools/objtool/arch/arm64/include/insn_decode.h
+++ b/tools/objtool/arch/arm64/include/insn_decode.h
@@ -135,6 +135,9 @@ int arm_decode_atomic(u32 instr, enum insn_type *type,
 int arm_decode_ld_st_regs_off(u32 instr, enum insn_type *type,
 			      unsigned long *immediate,
 			      struct list_head *ops_list);
+int arm_decode_ld_st_regs_pac(u32 instr, enum insn_type *type,
+			      unsigned long *immediate,
+			      struct list_head *ops_list);
 int arm_decode_ld_st_regs_unsigned(u32 instr, enum insn_type *type,
 				   unsigned long *immediate,
 				   struct list_head *ops_list);
-- 
2.21.0