From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from canpmsgout02.his.huawei.com (canpmsgout02.his.huawei.com [113.46.200.217]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0EC50430BB9 for ; Mon, 2 Mar 2026 03:50:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=113.46.200.217 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772423449; cv=none; b=DBuZzGDBXpkymRkmZQmds63AAoa3O3UWXy+Ihv4iu5xL6/VF8lMlbYwBjxqcXQkNkMUqmW5ViT4VRyxGHPDO9e8/91J0u0Y9Ee3Ve+U4n0KNyVO0uVmsum8UdkHMkqCIzYaxzuzm6IODbLirdffOmNVFymEkdR6O3rbKXDp+ENY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772423449; c=relaxed/simple; bh=oBs0/VOAE10caFYlBjetKO2BmpZjrM1KYrAYDiDCdeM=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=nmFk5vJIXb/JtNnA9P8sLSVfyENR5Gcr3SsR2kkvX7dcOrBbcM3zQTiKBA6FMNHkJcelFmw9TjDL58wHrSnu9/4t5OU1++Cr0n78ybqeHM14THIzU9WYz9EiogphGj5ekfbRlnr5zv6gxgVMltyGVgKYwpF85rcsOpYOAeQJ7zc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b=doUGLJfX; arc=none smtp.client-ip=113.46.200.217 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b="doUGLJfX" dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=ebc2xyrRyErhkT8LzvrdxHoB7dac5yeu5XdhGFduWAM=; b=doUGLJfXUykL5SCzxoXi8i0ghUoqhoUOUz1xbYrq8TewnsQ/smWtiFkvjRR5gaA81FbnreBFB RUSVavbSKPVFfU00b/KLNnEQ3zB6fgu8ts8J324gp2KsSp7vDqZmQ9FQjUDMHMVDBMc4dqnN5Ns Zpcr7KPXJYVTqTpaRxbx9n8= Received: from mail.maildlp.com (unknown [172.19.163.0]) by canpmsgout02.his.huawei.com (SkyGuard) with ESMTPS id 4fPPwG4JnczcZxn; Mon, 2 Mar 2026 11:45:34 +0800 (CST) Received: from kwepemk500005.china.huawei.com (unknown [7.202.194.90]) by mail.maildlp.com (Postfix) with ESMTPS id 1A6DC4036C; Mon, 2 Mar 2026 11:50:44 +0800 (CST) Received: from [10.67.120.222] (10.67.120.222) by kwepemk500005.china.huawei.com (7.202.194.90) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Mon, 2 Mar 2026 11:50:43 +0800 Message-ID: <3400c77a-8af2-4c06-8d8a-e718b6f72cfb@huawei.com> Date: Mon, 2 Mar 2026 11:50:43 +0800 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] selftests/arm64: Implement cmpbr_sigill() to hwcap test To: Mark Brown CC: , , , , , , , , , , , , , References: <20260227031933.4103333-1-wuyifan50@huawei.com> <20260227031933.4103333-2-wuyifan50@huawei.com> From: wuyifan In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: kwepems500002.china.huawei.com (7.221.188.17) To kwepemk500005.china.huawei.com (7.202.194.90) Hi Mark, On 2/28/2026 9:23 PM, Mark Brown wrote: > On Fri, Feb 27, 2026 at 11:19:32AM +0800, Yifan Wu wrote: > >> static void cmpbr_sigill(void) >> { >> - /* Not implemented, too complicated and unreliable anyway */ >> + /* CBEQ x0, x0, +8 */ >> + asm volatile(".inst 0x74C00040" : : : "x0"); >> + /* UDF #0 */ >> + asm volatile("udf #0" : : : ); >> } > I don't expect it to make a difference but it'd be nice if these were a > single asm volatile statement, just to make it absolutely clear that no > instrumentation or anything is supposed to go between the two. Thanks for the review. That's a good point, I'll combine them in v2. Regards, Yifan Wu