Messages in this thread Patch in this message | | | From | Raphael Gault <> | Subject | [RFC v4 07/18] objtool: Introduce INSN_UNKNOWN type | Date | Fri, 16 Aug 2019 13:23:52 +0100 |
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On arm64 some object files contain data stored in the .text section. This data is interpreted by objtool as instruction but can't be identified as a valid one. In order to keep analysing those files we introduce INSN_UNKNOWN type. The "unknown instruction" warning will thus only be raised if such instructions are uncountered while validating an execution branch.
This change doesn't impact the x86 decoding logic since 0 is still used as a way to specify an unknown type, raising the "unknown instruction" warning during the decoding phase still.
Signed-off-by: Raphael Gault <raphael.gault@arm.com> --- tools/objtool/arch.h | 1 + tools/objtool/arch/arm64/decode.c | 8 ++++---- tools/objtool/arch/arm64/include/insn_decode.h | 4 ++-- tools/objtool/check.c | 10 +++++++++- 4 files changed, 16 insertions(+), 7 deletions(-)
diff --git a/tools/objtool/arch.h b/tools/objtool/arch.h index 68d6371a24a2..9f2590e1df79 100644 --- a/tools/objtool/arch.h +++ b/tools/objtool/arch.h @@ -28,6 +28,7 @@ enum insn_type { INSN_CLAC, INSN_STD, INSN_CLD, + INSN_UNKNOWN, INSN_OTHER, }; diff --git a/tools/objtool/arch/arm64/decode.c b/tools/objtool/arch/arm64/decode.c index be3d2eb10227..4cb9402d6fe1 100644 --- a/tools/objtool/arch/arm64/decode.c +++ b/tools/objtool/arch/arm64/decode.c @@ -37,9 +37,9 @@ */ static arm_decode_class aarch64_insn_class_decode_table[] = { [INSN_RESERVED] = arm_decode_reserved, - [INSN_UNKNOWN] = arm_decode_unknown, + [INSN_UNALLOC_1] = arm_decode_unknown, [INSN_SVE_ENC] = arm_decode_sve_encoding, - [INSN_UNALLOC] = arm_decode_unknown, + [INSN_UNALLOC_2] = arm_decode_unknown, [INSN_LD_ST_4] = arm_decode_ld_st, [INSN_DP_REG_5] = arm_decode_dp_reg, [INSN_LD_ST_6] = arm_decode_ld_st, @@ -191,7 +191,7 @@ int arch_decode_instruction(struct elf *elf, struct section *sec, int arm_decode_unknown(u32 instr, unsigned char *type, unsigned long *immediate, struct stack_op *op) { - *type = 0; + *type = INSN_UNKNOWN; return 0; } @@ -206,7 +206,7 @@ int arm_decode_reserved(u32 instr, unsigned char *type, unsigned long *immediate, struct stack_op *op) { *immediate = instr & ONES(16); - *type = INSN_BUG; + *type = INSN_UNKNOWN; return 0; } diff --git a/tools/objtool/arch/arm64/include/insn_decode.h b/tools/objtool/arch/arm64/include/insn_decode.h index eb54fc39dca5..a01d76306749 100644 --- a/tools/objtool/arch/arm64/include/insn_decode.h +++ b/tools/objtool/arch/arm64/include/insn_decode.h @@ -20,9 +20,9 @@ #include "../../../arch.h" #define INSN_RESERVED 0b0000 -#define INSN_UNKNOWN 0b0001 +#define INSN_UNALLOC_1 0b0001 #define INSN_SVE_ENC 0b0010 -#define INSN_UNALLOC 0b0011 +#define INSN_UNALLOC_2 0b0011 #define INSN_DP_IMM 0b1001 //0x100x #define INSN_BRANCH 0b1011 //0x101x #define INSN_LD_ST_4 0b0100 //0bx1x0 diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 519569b0329f..baa6a93f37cd 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1981,6 +1981,13 @@ static int validate_branch(struct objtool_file *file, struct symbol *func, while (1) { next_insn = next_insn_same_sec(file, insn); + if (insn->type == INSN_UNKNOWN) { + WARN("%s+0x%lx unknown instruction type, should never be reached", + insn->sec->name, + insn->offset); + return 1; + } + if (file->c_file && func && insn->func && func != insn->func->pfunc) { WARN("%s() falls through to next function %s()", func->name, insn->func->name); @@ -2414,7 +2421,8 @@ static int validate_reachable_instructions(struct objtool_file *file) return 0; for_each_insn(file, insn) { - if (insn->visited || ignore_unreachable_insn(insn)) + if (insn->visited || ignore_unreachable_insn(insn) || + insn->type == INSN_UNKNOWN) continue; WARN_FUNC("unreachable instruction", insn->sec, insn->offset); -- 2.17.1
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