diff options
| author | Tiezhu Yang <yangtiezhu@loongson.cn> | 2025-09-18 19:43:36 +0800 |
|---|---|---|
| committer | Huacai Chen <chenhuacai@loongson.cn> | 2025-09-18 19:43:36 +0800 |
| commit | 539d7344d4feaea37e05863e9aa86bd31f28e46f (patch) | |
| tree | 80616f1d9dea0b225d72634d68ed6b291ee3742e | |
| parent | baad7830ee9a56756b3857348452fe756cb0a702 (diff) | |
objtool/LoongArch: Mark special atomic instruction as INSN_BUG type
When compiling with LLVM and CONFIG_RUST is set, there exists the
following objtool warning:
rust/compiler_builtins.o: warning: objtool: __rust__unordsf2(): unexpected end of section .text.unlikely.
objdump shows that the end of section .text.unlikely is an atomic
instruction:
amswap.w $zero, $ra, $zero
According to the LoongArch Reference Manual, if the amswap.w atomic
memory access instruction has the same register number as rd and rj,
the execution will trigger an Instruction Non-defined Exception, so
mark the above instruction as INSN_BUG type to fix the warning.
Cc: stable@vger.kernel.org
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
| -rw-r--r-- | tools/arch/loongarch/include/asm/inst.h | 12 | ||||
| -rw-r--r-- | tools/objtool/arch/loongarch/decode.c | 21 |
2 files changed, 33 insertions, 0 deletions
diff --git a/tools/arch/loongarch/include/asm/inst.h b/tools/arch/loongarch/include/asm/inst.h index c25b5853181d..d68fad63c8b7 100644 --- a/tools/arch/loongarch/include/asm/inst.h +++ b/tools/arch/loongarch/include/asm/inst.h @@ -51,6 +51,10 @@ enum reg2i16_op { bgeu_op = 0x1b, }; +enum reg3_op { + amswapw_op = 0x70c0, +}; + struct reg0i15_format { unsigned int immediate : 15; unsigned int opcode : 17; @@ -96,6 +100,13 @@ struct reg2i16_format { unsigned int opcode : 6; }; +struct reg3_format { + unsigned int rd : 5; + unsigned int rj : 5; + unsigned int rk : 5; + unsigned int opcode : 17; +}; + union loongarch_instruction { unsigned int word; struct reg0i15_format reg0i15_format; @@ -105,6 +116,7 @@ union loongarch_instruction { struct reg2i12_format reg2i12_format; struct reg2i14_format reg2i14_format; struct reg2i16_format reg2i16_format; + struct reg3_format reg3_format; }; #define LOONGARCH_INSN_SIZE sizeof(union loongarch_instruction) diff --git a/tools/objtool/arch/loongarch/decode.c b/tools/objtool/arch/loongarch/decode.c index 428ba6de3821..2e555c4060c5 100644 --- a/tools/objtool/arch/loongarch/decode.c +++ b/tools/objtool/arch/loongarch/decode.c @@ -278,6 +278,25 @@ static bool decode_insn_reg2i16_fomat(union loongarch_instruction inst, return true; } +static bool decode_insn_reg3_fomat(union loongarch_instruction inst, + struct instruction *insn) +{ + switch (inst.reg3_format.opcode) { + case amswapw_op: + if (inst.reg3_format.rd == LOONGARCH_GPR_ZERO && + inst.reg3_format.rk == LOONGARCH_GPR_RA && + inst.reg3_format.rj == LOONGARCH_GPR_ZERO) { + /* amswap.w $zero, $ra, $zero */ + insn->type = INSN_BUG; + } + break; + default: + return false; + } + + return true; +} + int arch_decode_instruction(struct objtool_file *file, const struct section *sec, unsigned long offset, unsigned int maxlen, struct instruction *insn) @@ -309,6 +328,8 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec return 0; if (decode_insn_reg2i16_fomat(inst, insn)) return 0; + if (decode_insn_reg3_fomat(inst, insn)) + return 0; if (inst.word == 0) { /* andi $zero, $zero, 0x0 */ |