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authorPaul E. McKenney <paulmck@kernel.org>2022-09-28 21:17:05 +0300
committerPaul E. McKenney <paulmck@kernel.org>2022-10-21 01:02:27 +0300
commit6cc9203b8e325d0ef21a7dc345d04fdb50b52a8a (patch)
treed3c4afea980996fd6fe3f96549e3fea2070ba843 /arch/arm64/Kconfig
parent49f88c70edccf4c967697597e0b99072dc4007c2 (diff)
downloadlinux-6cc9203b8e325d0ef21a7dc345d04fdb50b52a8a.tar.xz
arch/arm64: Add ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option
The arm64 architecture uses either an LL/SC loop (old systems) or an LSE stadd 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 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: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Ogness <john.ogness@linutronix.de> Cc: Petr Mladek <pmladek@suse.com> Cc: <linux-arm-kernel@lists.infradead.org>
Diffstat (limited to 'arch/arm64/Kconfig')
-rw-r--r--arch/arm64/Kconfig1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 505c8a1ccbe0..099ee812f3f1 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -31,6 +31,7 @@ config ARM64
select ARCH_HAS_KCOV
select ARCH_HAS_KEEPINITRD
select ARCH_HAS_MEMBARRIER_SYNC_CORE
+ select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
select ARCH_HAS_PTE_DEVMAP
select ARCH_HAS_PTE_SPECIAL