From: "Paul E. McKenney" <paulmck@kernel.org> To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com, rostedt@goodmis.org, "Paul E. McKenney" <paulmck@kernel.org>, Neeraj Upadhyay <quic_neeraju@quicinc.com>, Frederic Weisbecker <frederic@kernel.org>, Boqun Feng <boqun.feng@gmail.com>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, John Ogness <john.ogness@linutronix.de>, Petr Mladek <pmladek@suse.com>, linux-arm-kernel@lists.infradead.org Subject: [PATCH RFC v2 rcu 6/8] arch/arm64: Add ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option Date: Thu, 29 Sep 2022 11:07:29 -0700 [thread overview] Message-ID: <20220929180731.2875722-6-paulmck@kernel.org> (raw) In-Reply-To: <20220929180714.GA2874192@paulmck-ThinkPad-P17-Gen-1> 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> --- arch/arm64/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 571cc234d0b3..664725a0b5dd 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 -- 2.31.1.189.g2e36527f23
WARNING: multiple messages have this Message-ID (diff)
From: "Paul E. McKenney" <paulmck@kernel.org> To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com, rostedt@goodmis.org, "Paul E. McKenney" <paulmck@kernel.org>, Neeraj Upadhyay <quic_neeraju@quicinc.com>, Frederic Weisbecker <frederic@kernel.org>, Boqun Feng <boqun.feng@gmail.com>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, John Ogness <john.ogness@linutronix.de>, Petr Mladek <pmladek@suse.com>, linux-arm-kernel@lists.infradead.org Subject: [PATCH RFC v2 rcu 6/8] arch/arm64: Add ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option Date: Thu, 29 Sep 2022 11:07:29 -0700 [thread overview] Message-ID: <20220929180731.2875722-6-paulmck@kernel.org> (raw) In-Reply-To: <20220929180714.GA2874192@paulmck-ThinkPad-P17-Gen-1> 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> --- arch/arm64/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 571cc234d0b3..664725a0b5dd 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 -- 2.31.1.189.g2e36527f23 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-09-29 18:08 UTC|newest] Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-09-21 14:46 [PATCH rcu 0/4] NMI-safe SRCU reader API Paul E. McKenney 2022-09-21 14:46 ` [PATCH RFC rcu 1/4] srcu: Convert ->srcu_lock_count and ->srcu_unlock_count to atomic Paul E. McKenney 2022-09-21 14:46 ` [PATCH RFC rcu 2/4] srcu: Create and srcu_read_lock_nmisafe() and srcu_read_unlock_nmisafe() Paul E. McKenney 2022-09-21 14:46 ` [PATCH RFC rcu 3/4] srcu: Check for consistent per-CPU per-srcu_struct NMI safety Paul E. McKenney 2022-09-21 14:46 ` [PATCH RFC rcu 4/4] srcu: Check for consistent global " Paul E. McKenney 2022-09-29 18:07 ` [PATCH v2 rcu 0/8] NMI-safe SRCU reader API Paul E. McKenney 2022-09-29 18:07 ` [PATCH RFC v2 rcu 1/8] srcu: Convert ->srcu_lock_count and ->srcu_unlock_count to atomic Paul E. McKenney 2022-09-30 15:02 ` John Ogness 2022-09-30 15:35 ` Paul E. McKenney 2022-09-30 20:37 ` John Ogness 2022-10-01 16:51 ` Paul E. McKenney 2022-09-29 18:07 ` [PATCH RFC v2 rcu 2/8] srcu: Create an srcu_read_lock_nmisafe() and srcu_read_unlock_nmisafe() Paul E. McKenney 2022-10-02 15:55 ` Frederic Weisbecker 2022-10-02 15:57 ` Frederic Weisbecker 2022-10-02 16:10 ` Paul E. McKenney 2022-10-02 16:09 ` Paul E. McKenney 2022-10-02 21:47 ` Frederic Weisbecker 2022-10-02 23:46 ` Paul E. McKenney 2022-10-03 9:55 ` Frederic Weisbecker 2022-10-03 11:52 ` Paul E. McKenney 2022-10-18 14:31 ` John Ogness 2022-10-18 15:18 ` Paul E. McKenney 2022-09-29 18:07 ` [PATCH RFC v2 rcu 3/8] srcu: Check for consistent per-CPU per-srcu_struct NMI safety Paul E. McKenney 2022-10-02 22:06 ` Frederic Weisbecker 2022-10-02 23:51 ` Paul E. McKenney 2022-10-03 10:13 ` Frederic Weisbecker 2022-10-03 11:57 ` Paul E. McKenney 2022-10-03 12:37 ` Frederic Weisbecker 2022-10-03 13:32 ` Paul E. McKenney 2022-10-03 13:36 ` Frederic Weisbecker 2022-09-29 18:07 ` [PATCH RFC v2 rcu 4/8] srcu: Check for consistent global " Paul E. McKenney 2022-09-29 18:07 ` [PATCH RFC v2 rcu 5/8] arch/x86: Add ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option Paul E. McKenney 2022-09-29 18:07 ` Paul E. McKenney [this message] 2022-09-29 18:07 ` [PATCH RFC v2 rcu 6/8] arch/arm64: " Paul E. McKenney 2022-10-05 11:12 ` Mark Rutland 2022-10-05 11:12 ` Mark Rutland 2022-09-29 18:07 ` [PATCH RFC v2 rcu 7/8] arch/loongarch: " Paul E. McKenney 2022-09-29 18:07 ` [PATCH RFC v2 rcu 8/8] arch/s390: " Paul E. McKenney 2022-10-03 14:11 ` [PATCH v2 rcu 0/8] NMI-safe SRCU reader API Frederic Weisbecker 2022-10-03 16:38 ` Paul E. McKenney 2022-10-14 22:47 ` Joel Fernandes 2022-10-14 22:52 ` Joel Fernandes 2022-10-18 10:33 ` John Ogness 2022-10-18 15:24 ` Paul E. McKenney 2022-10-18 18:44 ` John Ogness 2022-10-18 18:59 ` Paul E. McKenney 2022-10-18 21:57 ` Paul E. McKenney 2022-10-19 11:13 ` John Ogness 2022-10-19 19:14 ` Paul E. McKenney 2022-10-19 21:38 ` John Ogness 2022-10-19 22:05 ` Frederic Weisbecker 2022-10-20 22:27 ` Paul E. McKenney 2022-10-20 22:41 ` Paul E. McKenney 2022-10-21 12:27 ` John Ogness 2022-10-21 13:59 ` Paul E. McKenney 2022-10-21 18:41 ` Paul E. McKenney 2022-10-24 6:15 ` John Ogness 2022-10-24 13:47 ` Paul E. McKenney 2022-10-27 9:31 ` John Ogness 2022-10-27 14:10 ` Paul E. McKenney 2022-10-27 14:39 ` John Ogness 2022-10-27 16:01 ` Paul E. McKenney
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