Messages in this thread Patch in this message | | | From | "Paul E. McKenney" <> | Subject | [PATCH RFC v2 rcu 7/8] arch/loongarch: Add ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option | Date | Thu, 29 Sep 2022 11:07:30 -0700 |
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The loongarch architecture uses the atomic read-modify-write amadd instruction to implement this_cpu_add(), which is 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/x86/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: Huacai Chen <chenhuacai@kernel.org> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Ogness <john.ogness@linutronix.de> Cc: Petr Mladek <pmladek@suse.com> Cc: <loongarch@lists.linux.dev> --- arch/loongarch/Kconfig | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig index 4abc9a28aba4..c8864768dc4d 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -10,6 +10,7 @@ config LOONGARCH select ARCH_ENABLE_MEMORY_HOTPLUG select ARCH_ENABLE_MEMORY_HOTREMOVE select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI + select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS select ARCH_HAS_PHYS_TO_DMA select ARCH_HAS_PTE_SPECIAL select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST -- 2.31.1.189.g2e36527f23
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