Decode load/store operations and create corresponding stack_ops for operations targetting SP or FP. Operations storing/loading multiple registers are split into separate stack_ops storing single registers. Operations modifying the base register get an additional stack_op for the register update. Since the atomic register(s) load/store + base register update gets split into multiple operations, to make sure objtool always sees a valid stack, consider store instruction to perform stack allocations (i.e. modifying the base pointer before the storing) and loads de-allocations (i.e. modifying the base pointer after the load). Signed-off-by: Julien Thierry <jthierry@xxxxxxxxxx> --- tools/objtool/arch/arm64/decode.c | 127 ++++++++++++++++++++++++++++++ 1 file changed, 127 insertions(+) diff --git a/tools/objtool/arch/arm64/decode.c b/tools/objtool/arch/arm64/decode.c index a4a587c400a1..1087ede67bcd 100644 --- a/tools/objtool/arch/arm64/decode.c +++ b/tools/objtool/arch/arm64/decode.c @@ -105,6 +105,40 @@ int arch_decode_hint_reg(struct instruction *insn, u8 sp_reg) return -1; } +static struct stack_op *arm_make_store_op(enum aarch64_insn_register base, + enum aarch64_insn_register reg, + int offset) +{ + struct stack_op *op; + + op = calloc(1, sizeof(*op)); + op->dest.type = OP_DEST_REG_INDIRECT; + op->dest.reg = base; + op->dest.offset = offset; + op->src.type = OP_SRC_REG; + op->src.reg = reg; + op->src.offset = 0; + + return op; +} + +static struct stack_op *arm_make_load_op(enum aarch64_insn_register base, + enum aarch64_insn_register reg, + int offset) +{ + struct stack_op *op; + + op = calloc(1, sizeof(*op)); + op->dest.type = OP_DEST_REG; + op->dest.reg = reg; + op->dest.offset = 0; + op->src.type = OP_SRC_REG_INDIRECT; + op->src.reg = base; + op->src.offset = offset; + + return op; +} + static struct stack_op *arm_make_add_op(enum aarch64_insn_register dest, enum aarch64_insn_register src, int val) @@ -121,6 +155,94 @@ static struct stack_op *arm_make_add_op(enum aarch64_insn_register dest, return op; } +static bool arm_decode_load_store(u32 insn, enum insn_type *type, + unsigned long *immediate, + struct list_head *ops_list) +{ + enum aarch64_insn_register base; + enum aarch64_insn_register rt; + struct stack_op *op; + int size; + int offset; + + *type = INSN_OTHER; + + if (aarch64_insn_is_store_single(insn) || + aarch64_insn_is_load_single(insn)) + size = 1 << ((insn & GENMASK(31, 30)) >> 30); + else + size = 4 << ((insn >> 31) & 1); + + if (aarch64_insn_is_store_imm(insn) || aarch64_insn_is_load_imm(insn)) + *immediate = size * aarch64_insn_decode_immediate(AARCH64_INSN_IMM_12, + insn); + else if (aarch64_insn_is_store_pre(insn) || + aarch64_insn_is_load_pre(insn) || + aarch64_insn_is_store_post(insn) || + aarch64_insn_is_load_post(insn)) + *immediate = sign_extend(aarch64_insn_decode_immediate(AARCH64_INSN_IMM_9, + insn), + 9); + else if (aarch64_insn_is_stp(insn) || aarch64_insn_is_ldp(insn) || + aarch64_insn_is_stp_pre(insn) || + aarch64_insn_is_ldp_pre(insn) || + aarch64_insn_is_stp_post(insn) || + aarch64_insn_is_ldp_post(insn)) + *immediate = size * sign_extend(aarch64_insn_decode_immediate(AARCH64_INSN_IMM_7, + insn), + 7); + else + return false; + + base = aarch64_insn_decode_register(AARCH64_INSN_REGTYPE_RN, insn); + if (base != AARCH64_INSN_REG_FP && base != AARCH64_INSN_REG_SP) + return true; + + offset = *immediate; + + if (aarch64_insn_is_store_pre(insn) || aarch64_insn_is_stp_pre(insn) || + aarch64_insn_is_store_post(insn) || aarch64_insn_is_stp_post(insn)) { + op = arm_make_add_op(base, base, *immediate); + list_add_tail(&op->list, ops_list); + + if (aarch64_insn_is_store_post(insn) || aarch64_insn_is_stp_post(insn)) + offset = -*immediate; + else + offset = 0; + } else if (aarch64_insn_is_load_post(insn) || aarch64_insn_is_ldp_post(insn)) { + offset = 0; + } + + /* First register */ + rt = aarch64_insn_decode_register(AARCH64_INSN_REGTYPE_RT, insn); + if (aarch64_insn_is_store_single(insn) || + aarch64_insn_is_store_pair(insn)) + op = arm_make_store_op(base, rt, offset); + else + op = arm_make_load_op(base, rt, offset); + list_add_tail(&op->list, ops_list); + + /* Second register (if present) */ + if (aarch64_insn_is_store_pair(insn) || + aarch64_insn_is_load_pair(insn)) { + rt = aarch64_insn_decode_register(AARCH64_INSN_REGTYPE_RT2, + insn); + if (aarch64_insn_is_store_pair(insn)) + op = arm_make_store_op(base, rt, offset + size); + else + op = arm_make_load_op(base, rt, offset + size); + list_add_tail(&op->list, ops_list); + } + + if (aarch64_insn_is_load_pre(insn) || aarch64_insn_is_ldp_pre(insn) || + aarch64_insn_is_load_post(insn) || aarch64_insn_is_ldp_post(insn)) { + op = arm_make_add_op(base, base, *immediate); + list_add_tail(&op->list, ops_list); + } + + return true; +} + static void arm_decode_add_sub_imm(u32 instr, bool set_flags, enum insn_type *type, unsigned long *immediate, @@ -234,6 +356,11 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, *type = INSN_OTHER; } break; + case AARCH64_INSN_CLS_LDST: + if (arm_decode_load_store(insn, type, immediate, ops_list)) + break; + *type = INSN_OTHER; + break; default: *type = INSN_OTHER; break; -- 2.25.4