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McKenney" , rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com, rostedt@goodmis.org, Neeraj Upadhyay , Frederic Weisbecker , Boqun Feng , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Sven Schnelle , Thomas Gleixner , John Ogness , Petr Mladek , linux-s390@vger.kernel.org References: <20221019225838.GA2500612@paulmck-ThinkPad-P17-Gen-1> <20221019225846.2501109-8-paulmck@kernel.org> Content-Language: en-US From: Christian Borntraeger In-Reply-To: <20221019225846.2501109-8-paulmck@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed X-TM-AS-GCONF: 00 X-Proofpoint-GUID: JLD47XnEjZuXK5fP6AH8MFxtxqmnzhJ8 X-Proofpoint-ORIG-GUID: lKMJ8UibkdU9hWACLHOimuOXOdYYZxRb Content-Transfer-Encoding: 7bit X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-10-20_01,2022-10-19_04,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 suspectscore=0 priorityscore=1501 mlxscore=0 bulkscore=0 mlxlogscore=999 phishscore=0 spamscore=0 adultscore=0 clxscore=1011 lowpriorityscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2209130000 definitions=main-2210200028 Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org Am 20.10.22 um 00:58 schrieb Paul E. McKenney: > The s390 architecture uses either a cmpxchg loop (old systems) > or the laa add-to-memory instruction (new systems) to implement > this_cpu_add(), both of which are NMI safe. This means that the old > and more-efficient srcu_read_lock() may be used in NMI context, without > the need for srcu_read_lock_nmisafe(). Therefore, add the new Kconfig > option ARCH_HAS_NMI_SAFE_THIS_CPU_OPS to arch/arm64/Kconfig, which will s390 ? > cause NEED_SRCU_NMI_SAFE to be deselected, thus preserving the current > srcu_read_lock() behavior. > > Link: https://lore.kernel.org/all/20220910221947.171557773@linutronix.de/ > > Suggested-by: Neeraj Upadhyay > Suggested-by: Frederic Weisbecker > Suggested-by: Boqun Feng > Signed-off-by: Paul E. McKenney > Cc: Heiko Carstens > Cc: Vasily Gorbik > Cc: Alexander Gordeev > Cc: Christian Borntraeger > Cc: Sven Schnelle > Cc: Thomas Gleixner > Cc: John Ogness > Cc: Petr Mladek > Cc: > --- > arch/s390/Kconfig | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig > index 318fce77601d3..0acdfda332908 100644 > --- a/arch/s390/Kconfig > +++ b/arch/s390/Kconfig > @@ -73,6 +73,7 @@ config S390 > select ARCH_HAS_GIGANTIC_PAGE > select ARCH_HAS_KCOV > select ARCH_HAS_MEM_ENCRYPT > + select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS > select ARCH_HAS_PTE_SPECIAL > select ARCH_HAS_SCALED_CPUTIME > select ARCH_HAS_SET_MEMORY