From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (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 715E4419FD2; Mon, 12 Oct 2026 11:42:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.158.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791805377; cv=none; b=KSx+JQcBikgRI3TRVbHtUoXPGxgqAeXb32T6UMoFPjuK5QEHVQtUtO/QNR6HhE+sLJY1pRzS39rm+D3+OrbZnDhpP9NM7ehGvKe4qvB2FNE4GRi+FJh0XXtvQiqoqJQX1vgpAHRalKIK53KXHw/+JAtjaq2vTQv175/LnysSDBo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791805377; c=relaxed/simple; bh=PrS2Um9x/0XCr8lbN6NSaMyiklWkk8/N1aZXcugQU+Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qOJ8LVQwHh9kNZfPJkLThXnl2nye6praA7jjVnd+1S5m8sgH95B0c9I3rO5CeonZTQmeWwY41gbc0wo4q5mwSsyTajduAwgZquXBcPQM+oxe7b9Zhsfw5OVlzllRKXYZL18W55QKNzPdzgMT5dvVj5u7lQTyiTSvjn5bYRkzmVI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=aqe8MUg0; arc=none smtp.client-ip=148.163.158.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="aqe8MUg0" Received: from pps.filterd (m0353725.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 69C8iS882750325; Mon, 12 Oct 2026 11:42:54 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc :content-transfer-encoding:date:from:in-reply-to:message-id :mime-version:references:subject:to; s=pp1; bh=MY294NXhdDrnkUDAX T8k8yJdOyr/XFHLy39o97zGbzE=; b=aqe8MUg06qiWGf5duEWmI7ClvAzHCiloF ZnQ13KwCscdjuQ42lh1tvY1c0Ok6neEnjmFGthFqHJwNyc8q5Jx5kytzd+qj6Rim X9iW5OR9YwT+n6FZs4ToUZ25WMkPmFZ1/66Ce64J8i7DJBXP39BJZuSbxDbaTQzq LxfoPxXsNpGem63k/DzkTDYLVv9byAWaIvooRyc1ATv21b80dVFvMonypN1s119I UzqsH2jolfh97cSZzkFcXP9/FAEckbE10L8cMs/e4NL5o4VdDx0X7SI+LfKi25xb H5lpVsnAlHTCSmAMFCrdlzGA6KVfwnu1UZskzvSu49KkLVL3f0+XQ== Received: from ppma12.dal12v.mail.ibm.com (dc.9e.1632.ip4.static.sl-reverse.com [50.22.158.220]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 4h7dv08bd2-1 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Mon, 12 Oct 2026 11:42:54 +0000 (GMT) Received: from pps.filterd (ppma12.dal12v.mail.ibm.com [127.0.0.1]) by ppma12.dal12v.mail.ibm.com (8.18.1.11/8.18.1.11) with ESMTP id 69C8K3nP964625; Mon, 12 Oct 2026 11:42:53 GMT Received: from smtprelay02.fra02v.mail.ibm.com ([9.218.2.226]) by ppma12.dal12v.mail.ibm.com (PPS) with ESMTPS id 4h7yppn43s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 12 Oct 2026 11:42:53 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (smtpav06.fra02v.mail.ibm.com [10.20.54.105]) by smtprelay02.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 69CBgokX55902568 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 12 Oct 2026 11:42:50 GMT Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id F1F4420049; Mon, 12 Oct 2026 11:42:49 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D80A62004D; Mon, 12 Oct 2026 11:42:49 +0000 (GMT) Received: from tuxmaker.lnxne.boe (unknown [9.87.85.9]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 12 Oct 2026 11:42:49 +0000 (GMT) From: Heiko Carstens To: Alexander Gordeev , Sven Schnelle , Vasily Gorbik , Christian Borntraeger Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org Subject: [PATCH 3/4] s390/percpu: Drop unused output register from arch_this_cpu_to_op() Date: Mon, 12 Oct 2026 13:42:48 +0200 Message-ID: <20261012114249.2898572-4-hca@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261012114249.2898572-1-hca@linux.ibm.com> References: <20261012114249.2898572-1-hca@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMDEyMDA0NCBTYWx0ZWRfX2AmdtsI69cyw d+MZPjClyfi+CwpYZYM28DXnvnWcucXxfJdp5iWg1C7X3Yy5OUgW2PDtdiY58wuxL5WxjV9xJDw jvChMPDaRZqzacLlHvp1VGGfzqlud7hpiaIqlCqMtKyZa5iF4y+s8u0SP1Y2WLZaKBmXlZ95DDj pTaX5RshuxSUuY0O7Z/1o1zu4z59rroOrX5DQlzBkkj4Ju8beleOHWzIghUzRFu7KXFV8QjSmUw tgAbjLqHIT/+bi4OMxOe21Hiju0fyeUe/PJjMjdNmhXx8P9GHD/5TJSUjAtXCg8NCAhdPAWUyPe 0c3k8ufRs7nHwymDXWLv8jBlu+vhc+8ijxZUolyrfcEBGHYzItPfF/D3hx/J0X5nzY7BYr2C+pJ sKzHJcCHYzf6bSq4Wa9eRltNnS2ze2MVRfrE3xTm3dNaFXQcLJQ4UNQx3v2vNpgaIWSL78pSddl rD51sdQ+QKg61wa+H3A== X-Proofpoint-Spam-Info: AW1haW4tMjYxMDEyMDA0NCBTYWx0ZWRfX8ILBS11FJXwx +cfO0lPK2X+6MczNjr60/gP015ucL8pNy3t3mdKEw2ppEcVbfQ2t4F+YfIVAI4qCQAGjp/MV37s 2BHNQ/pF0g5EtIs51XEjFcKntUS6H1A= X-Proofpoint-ORIG-GUID: DCx6V87RHHXpVcaziqR1u1fI4GpaIyVI X-Authority-Analysis: v=2.4 cv=a6KlZkSF c=1 sm=1 tr=0 ts=6accc7be cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=660iZSQnnn4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8 a=HZORN2dfYEM7eqIYgV4A:9 X-Proofpoint-GUID: DCx6V87RHHXpVcaziqR1u1fI4GpaIyVI X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-10-12_03,2026-10-09_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 malwarescore=0 spamscore=0 suspectscore=0 clxscore=1015 phishscore=0 priorityscore=1501 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2610080000 definitions=main-2610120044 The lan/lang/lao/laog instructions return the old memory content, but arch_this_cpu_to_op() does not need it. Instead of allocating a dedicated output register old__ just to discard the returned value, change the val__ constraint from "d" to "+&d" so it is used as input/output register. This reduces register pressure. Signed-off-by: Heiko Carstens --- arch/s390/include/asm/percpu.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/s390/include/asm/percpu.h b/arch/s390/include/asm/percpu.h index fd0a3a9951ce..7d87e0a262c3 100644 --- a/arch/s390/include/asm/percpu.h +++ b/arch/s390/include/asm/percpu.h @@ -257,18 +257,18 @@ do { \ typedef typeof(pcp) pcp_op_T__; \ union register_pair rp__; \ pcp_op_T__ val__ = (val); \ - pcp_op_T__ old__, *ptr__; \ + pcp_op_T__ *ptr__; \ \ ptr__ = PERCPU_PTR(&(pcp)); \ asm_inline volatile( \ __PCPU_BEGIN("%[lcreg]","%[lcoff]","%[ptr__]", \ "%[pair__]","%N[pair__]") \ - op " %[old__],%[val__],0(%N[pair__])\n" \ + op " %[val__],%[val__],0(%N[pair__])\n" \ __PCPU_END("%[lcreg]") \ - : [old__] "=&d" (old__), [pair__] "=&a" (rp__.pair), \ + : [val__] "+&d" (val__), [pair__] "=&a" (rp__.pair), \ "+m" (*ptr__), \ "=m" (((struct lowcore *)0)->percpu_register) \ - : [val__] "d" (val__), [ptr__] "a" (ptr__), \ + : [ptr__] "a" (ptr__), \ [lcreg] "i" (LC_PERCPU_REGISTER), \ [lcoff] "i" (LC_PERCPU_OFFSET), \ "m" (((struct lowcore *)0)->percpu_offset) \ -- 2.53.0