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Subject[RFC v5 34/57] objtool: arm64: Decode load/store exclusive
Date
Decode load/store exclusive instructions. From objtool's point
of view there aren't particular semantics to these operations.

Suggested-by: Raphael Gault <raphael.gault@arm.com>
Signed-off-by: Julien Thierry <jthierry@redhat.com>
---
tools/objtool/arch/arm64/decode.c | 140 ++++++++++++++++++
.../objtool/arch/arm64/include/insn_decode.h | 3 +
2 files changed, 143 insertions(+)

diff --git a/tools/objtool/arch/arm64/decode.c b/tools/objtool/arch/arm64/decode.c
index 7d480efe0bc2..e3f77d68b282 100644
--- a/tools/objtool/arch/arm64/decode.c
+++ b/tools/objtool/arch/arm64/decode.c
@@ -830,6 +830,11 @@ static struct aarch64_insn_decoder ld_st_decoder[] = {
.value = 0b000011100000000,
.decode_func = arm_decode_adv_simd_single_post,
},
+ {
+ .mask = 0b001111000000000,
+ .value = 0b000000000000000,
+ .decode_func = arm_decode_ld_st_exclusive,
+ },
{
.mask = 0b001101100000000,
.value = 0b001000000000000,
@@ -1190,6 +1195,141 @@ int arm_decode_adv_simd_single_post(u32 instr, enum insn_type *type,
return ret;
}

+#define ST_EXCL_UNALLOC_1 0b001010
+#define ST_EXCL_UNALLOC_2 0b000010
+
+#define LDXRB 0b000100
+#define LDAXRB 0b000101
+#define LDLARB 0b001100
+#define LDARB 0b001101
+#define LDXRH 0b010100
+#define LDAXRH 0b010101
+#define LDLARH 0b011100
+#define LDARH 0b011101
+#define LDXR 0b100100
+#define LDAXR 0b100101
+#define LDXP 0b100110
+#define LDAXP 0b100111
+#define LDLAR 0b101100
+#define LDAR 0b101101
+#define LDXR_64 0b110100
+#define LDAXR_64 0b110101
+#define LDXP_64 0b110110
+#define LDAXP_64 0b110111
+#define LDLAR_64 0b111100
+#define LDAR_64 0b111101
+
+#define LD_EXCL_NUMBER 20
+
+static int ld_excl_masks[] = {
+ LDXRB,
+ LDAXRB,
+ LDLARB,
+ LDARB,
+ LDXRH,
+ LDAXRH,
+ LDLARH,
+ LDARH,
+ LDXR,
+ LDAXR,
+ LDXP,
+ LDAXP,
+ LDLAR,
+ LDAR,
+ LDXR_64,
+ LDAXR_64,
+ LDXP_64,
+ LDAXP_64,
+ LDLAR_64,
+ LDAR_64,
+};
+
+int arm_decode_ld_st_exclusive(u32 instr, enum insn_type *type,
+ unsigned long *immediate,
+ struct list_head *ops_list)
+{
+ unsigned char size = 0, o2 = 0, L = 0, o1 = 0, o0 = 0;
+ unsigned char rt = 0, rt2 = 0, rn = 0;
+ unsigned char decode_field = 0;
+ struct stack_op *op;
+ int i = 0;
+
+ size = (instr >> 30) & ONES(2);
+ o2 = EXTRACT_BIT(instr, 23);
+ L = EXTRACT_BIT(instr, 22);
+ o1 = EXTRACT_BIT(instr, 21);
+ o0 = EXTRACT_BIT(instr, 15);
+
+ rt2 = (instr >> 10) & ONES(5);
+ rn = (instr >> 5) & ONES(5);
+ rt = instr & ONES(5);
+
+ decode_field = (size << 4) | (o2 << 3) | (L << 2) | (o1 << 1) | o0;
+
+ if ((decode_field & ST_EXCL_UNALLOC_1) == ST_EXCL_UNALLOC_1 ||
+ (decode_field & 0b101010) == ST_EXCL_UNALLOC_2) {
+ if (rt2 != 31)
+ return arm_decode_unknown(instr, type, immediate,
+ ops_list);
+ }
+
+ if (!stack_related_reg(rn)) {
+ *type = INSN_OTHER;
+ return 0;
+ }
+
+ *type = INSN_STACK;
+ op = calloc(1, sizeof(*op));
+ list_add_tail(&op->list, ops_list);
+
+ for (i = 0; i < LD_EXCL_NUMBER; i++) {
+ if ((decode_field & 0b111111) == ld_excl_masks[i]) {
+ op->src.type = OP_SRC_REG_INDIRECT;
+ op->src.reg = rn;
+ op->src.offset = 0;
+ op->dest.type = OP_DEST_REG;
+ op->dest.reg = rt;
+ op->dest.offset = 0;
+ return 0;
+ }
+ }
+
+ op->dest.type = OP_DEST_REG_INDIRECT;
+ op->dest.reg = rn;
+ op->dest.offset = 0;
+ op->src.type = OP_SRC_REG;
+ op->src.reg = rt;
+ op->src.offset = 0;
+
+ return 0;
+}
+
+#undef ST_EXCL_UNALLOC_1
+#undef ST_EXCL_UNALLOC_2
+
+#undef LD_EXCL_NUMBER
+
+#undef LDXRB
+#undef LDAXRB
+#undef LDLARB
+#undef LDARB
+#undef LDXRH
+#undef LDAXRH
+#undef LDLARH
+#undef LDARH
+#undef LDXR
+#undef LDAXR
+#undef LDXP
+#undef LDAXP
+#undef LDLAR
+#undef LDAR
+#undef LDXR_64
+#undef LDAXR_64
+#undef LDXP_64
+#undef LDAXP_64
+#undef LDLAR_64
+#undef LDAR_64
+
int arm_decode_ld_st_regs_unsc_imm(u32 instr, enum insn_type *type,
unsigned long *immediate,
struct list_head *ops_list)
diff --git a/tools/objtool/arch/arm64/include/insn_decode.h b/tools/objtool/arch/arm64/include/insn_decode.h
index 7fd333f88612..61152b4aa42a 100644
--- a/tools/objtool/arch/arm64/include/insn_decode.h
+++ b/tools/objtool/arch/arm64/include/insn_decode.h
@@ -136,4 +136,7 @@ int arm_decode_ld_st_regs_off(u32 instr, enum insn_type *type,
int arm_decode_ld_st_regs_unsigned(u32 instr, enum insn_type *type,
unsigned long *immediate,
struct list_head *ops_list);
+int arm_decode_ld_st_exclusive(u32 instr, enum insn_type *type,
+ unsigned long *immediate,
+ struct list_head *ops_list);
#endif /* _ARM_INSN_DECODE_H */
--
2.21.0
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