From nobody Sun Nov 24 13:24:17 2024 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A72941D5AA8 for ; Tue, 5 Nov 2024 12:39:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=114.242.206.163 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730810354; cv=none; b=gYrALtvdCRU8l/bxvhiIwPLkvSbRLtGW6ZAZY58d3y0WtZlENGXpRp3Zt+eg/VBEUKgYSmJM9ZKSJDvvquu7KyfjpBX1L+3cSDWUG1oWsosyoCJbro+nhTzYrV1DJ8V9Ku/HTudie2ogSLDVwkbIdZB9i11qK0lMdXnNpxRfHH4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730810354; c=relaxed/simple; bh=WuYh2QNbB1DXYMDkZ4MpKfVONFKDR2ri1ITDB4mHoqs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=G8M0SVXCBz7cXBk9z8BrFaP07JsGeFhxRbAcdIsqN6Yb0SOFupMBDrgNtROl6IiOo0Euwetw+8a5JWzKnAtwYXx14S8+oDPD7XClHpBAvTSawrpxmzw+EOjfqd2zeEsZz0PQLEqE+SfOM5jXsP8EFK5UD0jIJ/LR9M8F4Bhhti8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn; spf=pass smtp.mailfrom=loongson.cn; arc=none smtp.client-ip=114.242.206.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=loongson.cn Received: from loongson.cn (unknown [113.200.148.30]) by gateway (Coremail) with SMTP id _____8AxquHuESpnirUxAA--.36195S3; Tue, 05 Nov 2024 20:39:10 +0800 (CST) Received: from linux.localdomain (unknown [113.200.148.30]) by front1 (Coremail) with SMTP id qMiowMBxrsLsESpnw4lCAA--.26454S4; Tue, 05 Nov 2024 20:39:10 +0800 (CST) From: Tiezhu Yang To: Huacai Chen , Josh Poimboeuf , Peter Zijlstra Cc: loongarch@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/5] objtool: Handle special cases of discard.reachable Date: Tue, 5 Nov 2024 20:39:03 +0800 Message-ID: <20241105123906.26072-3-yangtiezhu@loongson.cn> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20241105123906.26072-1-yangtiezhu@loongson.cn> References: <20241105123906.26072-1-yangtiezhu@loongson.cn> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: qMiowMBxrsLsESpnw4lCAA--.26454S4 X-CM-SenderInfo: p1dqw3xlh2x3gn0dqz5rrqw2lrqou0/ X-Coremail-Antispam: 1Uk129KBj93XoW7CF4kuryfGr4DKr17uw47ZFc_yoW8WF4Dpa y5Cay3Jr4DXr48W3W7Wws5WryfKw4fGrW8XryfJ34UK3s8Xwn5KFn3tay2v3Zxua1ag3Wa qFsI934UZF1DArcCm3ZEXasCq-sJn29KB7ZKAUJUUUUr529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUU9Fb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1Y6r17M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVCY1x0267AK xVW8Jr0_Cr1UM2kKe7AKxVWUXVWUAwAS0I0E0xvYzxvE52x082IY62kv0487Mc804VCY07 AIYIkI8VC2zVCFFI0UMc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWU tVWrXwAv7VC2z280aVAFwI0_Gr0_Cr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7V AKI48JMxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMxCIbckI1I0E14v2 6r1Y6r17MI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17 CEb7AF67AKxVWUAVWUtwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r4j6ryUMIIF 0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIx AIcVC2z280aVAFwI0_Gr0_Cr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2 KfnxnUUI43ZEXa7IU8EeHDUUUUU== Content-Type: text/plain; charset="utf-8" There are some "unreachable instruction" objtool warnings when compling with Clang on LoongArch, this is because the "break" instruction is set as dead end due to its type is INSN_BUG in decode_instructions() at the beginning, and it does not set insn->dead_end of the "break" instruction as false after checking ".rela.discard.reachable" in add_dead_ends(), so the next instruction of "break" is marked as unreachable. Actually, it can find the reachable instruction after parsing the section ".rela.discard.reachable", in some cases, the "break" instruction may not be the first previous instruction with scheduling by Machine Instruction Scheduler of LLVM, it should find more times and then set insn->dead_end of the "break" instruction as false. This is preparation for later patch on LoongArch, there is no effect for the other archs with this patch. Signed-off-by: Tiezhu Yang --- tools/objtool/check.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 9601235e908d..6607cd56459b 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -711,6 +711,18 @@ static int add_dead_ends(struct objtool_file *file) } =20 insn->dead_end =3D false; + + /* Handle the special cases compiled with Clang on LoongArch */ + if (file->elf->ehdr.e_machine =3D=3D EM_LOONGARCH && + reloc->sym->type =3D=3D STT_SECTION) { + while (insn && insn_func(insn)) { + insn =3D prev_insn_same_sym(file, insn); + if (insn && insn->dead_end) { + insn->dead_end =3D false; + break; + } + } + } } =20 return 0; --=20 2.42.0