From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id D8FB71C6FF5 for ; Thu, 4 Sep 2025 01:26:53 +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=1756949217; cv=none; b=ThKCOgbfgloO5owLZYPjXQeswmgkvt5rATKBpaguq9qBfYS0uYZ1qDwcLxOcV6LmoNofpf4vWp/uh9nNIhyyhP0O186K3kHcZK6yTihk8CfGaV76en9HfwZ324mTVqqISQ0kP2JQ8KFD2GDRL1bzp5gSiJqTB6w0c3S9oWnSIZU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756949217; c=relaxed/simple; bh=cuaU9uG3GXxPtLcYoEepVCklgjJFmkWc6RMtvoPPB/k=; h=Subject:To:Cc:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=qEsx0+HyP69L5DnD+0NfYDLfZXqWQZMP0KHnoNoADcSFDo3UQRbQDk97hzM6Wi1k86PDAx/o3A7/DqLmNfiHf+KgU6ZuwKlA/XmQre5aUVcjb31CCTvuZum5Rt9e4lAcW3+UA+5IcaM0vCAWf4ybSL+YlVkfLe9nOUZxaYCQ2NU= 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 [111.9.175.10]) by gateway (Coremail) with SMTP id _____8Dx_tLY6rhoY3YGAA--.13572S3; Thu, 04 Sep 2025 09:26:48 +0800 (CST) Received: from [10.136.12.26] (unknown [111.9.175.10]) by front1 (Coremail) with SMTP id qMiowJDxrcHU6rholbt8AA--.41867S3; Thu, 04 Sep 2025 09:26:46 +0800 (CST) Subject: Re: [PATCH v1 3/3] LoongArch: Fix unreachable instruction warnings about entry functions To: Josh Poimboeuf , Tiezhu Yang Cc: Huacai Chen , Peter Zijlstra , Nathan Chancellor , loongarch@lists.linux.dev, linux-kernel@vger.kernel.org References: <20250901072156.31361-1-yangtiezhu@loongson.cn> <20250901072156.31361-4-yangtiezhu@loongson.cn> From: Jinyang He Message-ID: <93a93bcf-8778-a6a3-142d-c8aeb3cee5cd@loongson.cn> Date: Thu, 4 Sep 2025 09:26:43 +0800 User-Agent: Mozilla/5.0 (X11; Linux loongarch64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-CM-TRANSID:qMiowJDxrcHU6rholbt8AA--.41867S3 X-CM-SenderInfo: pkhmx0p1dqwqxorr0wxvrqhubq/ X-Coremail-Antispam: 1Uk129KBj93XoW7Xr4DWr4Uur4kAF47XrWfXrc_yoW8Jr4UpF y7CFsrXrWDKrnFywn8t3409FWDJa4DG342g3WDKFyFkwsFqr17Zr48Zr9rWFyqqw4Iy3yF qFn5W39rtF4UAacCm3ZEXasCq-sJn29KB7ZKAUJUUUU5529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUvjb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1Y6r17M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Gr0_Xr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_ GcCE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqjxCEc2xF0cIa020Ex4CE44I27wAqx4 xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jrv_JF1lYx0Ex4A2jsIE14v2 6r1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvEwIxGrwCYjI0SjxkI62AI1cAE67 vIY487MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAF wI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUAVWUtwCIc4 0Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AK xVWUJVW8JwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr 1lIxAIcVC2z280aVCY1x0267AKxVWUJVW8JbIYCTnIWIevJa73UjIFyTuYvjxU7_MaUUUU U On 2025-09-04 03:22, Josh Poimboeuf wrote: > On Mon, Sep 01, 2025 at 03:21:56PM +0800, Tiezhu Yang wrote: >> +++ b/arch/loongarch/kernel/Makefile >> @@ -3,8 +3,6 @@ >> # Makefile for the Linux/LoongArch kernel. >> # >> >> -OBJECT_FILES_NON_STANDARD_head.o := y >> - >> always-$(KBUILD_BUILTIN) := vmlinux.lds >> >> obj-y += head.o cpu-probe.o cacheinfo.o env.o setup.o entry.o genex.o \ >> diff --git a/arch/loongarch/kernel/head.S b/arch/loongarch/kernel/head.S >> index e3865e92a917..a11880f3a7e1 100644 >> --- a/arch/loongarch/kernel/head.S >> +++ b/arch/loongarch/kernel/head.S >> @@ -42,6 +42,7 @@ SYM_DATA(kernel_fsize, .long _kernel_fsize); >> .align 12 >> >> SYM_CODE_START(kernel_entry) # kernel entry point >> + UNWIND_HINT_UNDEFINED > Should this not be UNWIND_HINT_END_OF_STACK? > > I notice Loongarch doesn't seem to use that anywhere. How does any ORC > unwind succeed? IIRC, unwinder stops when fail when call __kernel_text_address(bt_address), or success when call arch/loongarch/kernel/unwind_orc.c::is_entry_func(bt_address). > UNWIND_HINT_UNDEFINED sets an error condition which > should cause a livepatch transition to stall. >