Messages in this thread | | | Date | Thu, 20 Oct 2022 07:16:44 +0200 | Subject | Re: [PATCH v3 rcu 08/11] arch/s390: Add ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option | From | Christian Borntraeger <> |
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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 <quic_neeraju@quicinc.com> > Suggested-by: Frederic Weisbecker <frederic@kernel.org> > Suggested-by: Boqun Feng <boqun.feng@gmail.com> > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > Cc: Heiko Carstens <hca@linux.ibm.com> > Cc: Vasily Gorbik <gor@linux.ibm.com> > Cc: Alexander Gordeev <agordeev@linux.ibm.com> > Cc: Christian Borntraeger <borntraeger@linux.ibm.com> > Cc: Sven Schnelle <svens@linux.ibm.com> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: John Ogness <john.ogness@linutronix.de> > Cc: Petr Mladek <pmladek@suse.com> > Cc: <linux-s390@vger.kernel.org> > --- > 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
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