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 5257031987F for ; Tue, 26 Aug 2025 12:27:19 +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=1756211244; cv=none; b=dSKDuVnGlc86YvIn4AFAhjkvJkB+0gQv9VDknb+ejqw+tN3jl43MDMIcOh7v7s8TySmG316FK3XWqSwU5MFOYRP6PONz0lQOWF3optIzVT2kRn6tiTMzbQh1Ubpj/65bq82y8lMbZNgOhPTX6s2WanP2LJVmddavJzALo53ZFy4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756211244; c=relaxed/simple; bh=lr/ktiqN8EGAwxTSlE1IH8BeTaDaJt2Zb2PkjFQqbHY=; h=Subject:To:Cc:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=nfHPdIN0EosW9T9JZPvg3RdiG2u2GJTpaGrGWJEjmkuv8KejlJC/HJs31DW5UBqwHYrYknxeZxcMYXZjRRcWtNY5G6cYW12KV43R7A7uQhmQsh3HxwFGBhfltC/I5xjKg729zUI7nKBGNxOogvW/XJkVs/fGY5ZtCHdy1rqRETs= 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 _____8Dxfb8lqK1oc1wDAA--.5461S3; Tue, 26 Aug 2025 20:27:17 +0800 (CST) Received: from [10.130.10.66] (unknown [113.200.148.30]) by front1 (Coremail) with SMTP id qMiowJBxzsEhqK1oQ_5pAA--.40668S3; Tue, 26 Aug 2025 20:27:14 +0800 (CST) Subject: Re: [RFC PATCH 2/2] objtool/LoongArch: Fix unreachable instruction warnings about head.S To: Peter Zijlstra Cc: Huacai Chen , Josh Poimboeuf , Nathan Chancellor , loongarch@lists.linux.dev, linux-kernel@vger.kernel.org References: <20250826064631.9617-1-yangtiezhu@loongson.cn> <20250826064631.9617-3-yangtiezhu@loongson.cn> <20250826082057.GE3245006@noisy.programming.kicks-ass.net> From: Tiezhu Yang Message-ID: <8dfe8bde-0095-d6c3-b9ca-cce2bf720ac2@loongson.cn> Date: Tue, 26 Aug 2025 20:27:13 +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: <20250826082057.GE3245006@noisy.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-CM-TRANSID:qMiowJBxzsEhqK1oQ_5pAA--.40668S3 X-CM-SenderInfo: p1dqw3xlh2x3gn0dqz5rrqw2lrqou0/ X-Coremail-Antispam: 1Uk129KBj93XoWrZrW7ZF4rCFykXFy3tw1DurX_yoW8JF17pF WUAw40kFZ8Jr1I9a13Ja1fWFyY9FZxXrWfGr1q9rySyayqyayjqr1agr1j9F9Iva9xKFyF vw4DtF909Fn8AagCm3ZEXasCq-sJn29KB7ZKAUJUUUU5529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUv0b4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1Y6r17M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_ GcCE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqjxCEc2xF0cIa020Ex4CE44I27wAqx4 xG64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jrv_JF1lYx0Ex4A2jsIE14v2 6r4j6F4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvEwIxGrwCYjI0SjxkI62AI1cAE67 vIY487MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAF wI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUAVWUtwCIc4 0Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AK xVWUJVW8JwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_Cr 1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7IU8vApUUU UUU== On 2025/8/26 下午4:20, Peter Zijlstra wrote: > On Tue, Aug 26, 2025 at 02:46:31PM +0800, Tiezhu Yang wrote: >> When compiling with LLVM and CONFIG_LTO_CLANG is set, there exist the >> following objtool warnings after silencing all of the other warnings: ... >> Just give a proper unwind hint to silence the above warnings. By the way, >> the previous instructions of kernel_entry+0xf4 and smpboot_entry+0x68 are >> the 'bl' instructions, the call destination symbols are start_kernel() and >> start_secondary() which are noreturn functions, then the 'bl' instructions >> are marked as dead end in annotate_call_site(), so actually ASM_BUG() can >> be removed due to unnecessary, otherwise there are following warnings: ... >> Link: https://lore.kernel.org/lkml/20250814083651.GR4067720@noisy.programming.kicks-ass.net/ >> Suggested-by: Peter Zijlstra >> Signed-off-by: Tiezhu Yang >> --- >> arch/loongarch/kernel/head.S | 8 ++++---- >> 1 file changed, 4 insertions(+), 4 deletions(-) > > At this point you should also be able to remove that Makefile thing, > right? Yes, you are right, will do it in the next version if this patch makes sense. Thanks, Tiezhu