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Fri, 22 May 2026 14:12:59 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.87.85.9]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 22 May 2026 14:12:59 +0000 (GMT) From: Heiko Carstens To: Alexander Gordeev , Sven Schnelle , Vasily Gorbik , Christian Borntraeger , Juergen Christ Cc: Peter Zijlstra , Yang Shi , Shrikanth Hegde , David Laight , linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org Subject: [PATCH v4 6/8] s390/percpu: Provide arch_this_cpu_read() implementation Date: Fri, 22 May 2026 16:12:55 +0200 Message-ID: <20260522141257.303617-7-hca@linux.ibm.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260522141257.303617-1-hca@linux.ibm.com> References: <20260522141257.303617-1-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-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNTIyMDE0MSBTYWx0ZWRfX88H+HOQvLCFC adZzs8a1mX+eV8eqSCOFWqkWb2zmAmDNs3pz2HSdttUmK58nP9RfknI2UwgvhS2/fowmlsbR2j+ 9jh9d3WhALBu8UrPk9iJxwWgbDTLPIp7XThrDPHj4T/dNHQ77/iG/sfaOGoETLMYr49Ivm66RoJ qyojxhiScEKYTe0nHvWl1pp36WQHjGAW0DnINbtigRtOuTxXJnL9fflo1bDMJ8TMNjw4hH8D8Xj ASbhPHprCkOP1qHoPc5SmSM5y8ITCwK1ArNzsS8fKJEOF0pMj73ojC+ZEcOlvK2kX6EBGma+hQ2 8Xm+7OnNM1gqjdVzwsxIePDOnzw3UTHz77XW88RySgSN7bmNwJvuhOtmaOupdp1xdIy/kL4EeJQ RP5yz8w+YJB0mMMLrFdwW7HqTxvsxwPajdwVYaxdmXGO5YslErqu/b91JjSnAesqGdRa0HCdwIY UOf3I1sYiQDCe5uJA4Q== X-Authority-Analysis: v=2.4 cv=BNuDalQG c=1 sm=1 tr=0 ts=6a106470 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=NGcC8JguVDcA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VnNF1IyMAAAA:8 a=4bOSrtcVyj7iNoH5sBwA:9 X-Proofpoint-ORIG-GUID: jGfygW6w-RgxBFKIUPPTnBHvqQ4l71VS X-Proofpoint-GUID: RKXgQKclBBQBFxEF3jERM2iumFDWL0U9 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-05-22_03,2026-05-18_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 priorityscore=1501 malwarescore=0 impostorscore=0 suspectscore=0 lowpriorityscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2605130000 definitions=main-2605220141 Provide an s390 specific implementation of arch_this_cpu_read() instead of the generic variant. The generic variant uses preempt_disable() / preempt_enable() pair and READ_ONCE(). Get rid of the preempt_disable() / preempt_enable() pairs by providing an own variant which makes use of the new percpu code section infrastructure. With this the text size of the kernel image is reduced by ~1k (defconfig). Also 87 generated preempt_schedule_notrace() function calls within the kernel image (modules not counted) are removed. Signed-off-by: Heiko Carstens --- arch/s390/include/asm/percpu.h | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/arch/s390/include/asm/percpu.h b/arch/s390/include/asm/percpu.h index 5e0185e5960b..2b6c2c5606b1 100644 --- a/arch/s390/include/asm/percpu.h +++ b/arch/s390/include/asm/percpu.h @@ -248,6 +248,37 @@ do { \ #endif /* MARCH_HAS_Z196_FEATURES */ +#define arch_this_cpu_read(pcp, op) \ +({ \ + unsigned long lc_pcpr, lc_pcpo, res__; \ + typedef typeof(pcp) pcp_op_T__; \ + pcp_op_T__ *ptr__; \ + \ + lc_pcpr = offsetof(struct lowcore, percpu_register); \ + lc_pcpo = offsetof(struct lowcore, percpu_offset); \ + ptr__ = PERCPU_PTR(&(pcp)); \ + asm_inline volatile( \ + MVIY_PERCPU("%[disppcpr]", "%[dispaltpcpr]", "%[ptr__]")\ + AG_ALT("%[disppcpo]", "%[dispaltpcpo]", "%[ptr__]") \ + op " %[res__],0(%[ptr__])\n" \ + MVIY_ALT("%[disppcpr]", "%[dispaltpcpr]") \ + : [res__] "=&d" (res__), [ptr__] "+&a" (ptr__), \ + "=m" (((struct lowcore *)0)->percpu_register) \ + : [disppcpr] "i" (lc_pcpr), \ + [disppcpo] "i" (lc_pcpo), \ + [dispaltpcpr] "i" (lc_pcpr + LOWCORE_ALT_ADDRESS), \ + [dispaltpcpo] "i" (lc_pcpo + LOWCORE_ALT_ADDRESS), \ + "m" (*ptr__), \ + "m" (((struct lowcore *)0)->percpu_offset) \ + : "cc"); \ + (pcp_op_T__)res__; \ +}) + +#define this_cpu_read_1(pcp) arch_this_cpu_read(pcp, "ic") +#define this_cpu_read_2(pcp) arch_this_cpu_read(pcp, "lh") +#define this_cpu_read_4(pcp) arch_this_cpu_read(pcp, "l") +#define this_cpu_read_8(pcp) arch_this_cpu_read(pcp, "lg") + #define arch_this_cpu_cmpxchg(pcp, oval, nval) \ ({ \ typedef typeof(pcp) pcp_op_T__; \ -- 2.51.0