From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D0E4C433EF for ; Tue, 28 Jun 2022 13:18:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346278AbiF1NSA (ORCPT ); Tue, 28 Jun 2022 09:18:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346334AbiF1NRa (ORCPT ); Tue, 28 Jun 2022 09:17:30 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 841A733345 for ; Tue, 28 Jun 2022 06:17:13 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id F0C11B81C17 for ; Tue, 28 Jun 2022 13:17:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E3F71C341CD; Tue, 28 Jun 2022 13:17:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1656422230; bh=GXxWnYxdiZTHc2gGq4iWUhB1u7I258RMn6fqlXqXF58=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SRkh75IaT0rukDHiX9tlSKet9O/CEi1arkBy1l0o796s2LnrTjp9kO5CbNrj0heVb WImFKLbOzg9qq+b6zvsM1hisC/SVIF3ZhRfW0edYNqe0RCbKwbVlCO+hXVo6fw454t 6gsJ7lpGW0w5xJAuxTRvkzjGI2zyW9soHFHekCwrL+UoAEXyFtHJeEJ7Ht6pLkrLtv zVd20MyFCi0Kcq5/jnFBzkR/nT/xJm4XyDsoMSW7kURP/3QVkTeEGYpciE1fhgpaQu xWRw1Y+17nQixERh/eJp45SRGOlffVRIGIT49eXW1YkSzSpkGkER2FqXzDDctkm602 rLXQfWAbcUacg== From: Frederic Weisbecker To: "Paul E . McKenney" Cc: LKML , Frederic Weisbecker , Peter Zijlstra , Phil Auld , Alex Belits , Nicolas Saenz Julienne , Marco Elver , Xiongfeng Wang , Neeraj Upadhyay , Thomas Gleixner , Nicolas Saenz Julienne , Max Filippov , Yu Liao , Boqun Feng , Marcelo Tosatti , kernel test robot , Paul Gortmaker , Uladzislau Rezki , Joel Fernandes Subject: [PATCH 10/20] context_tracking: Take NMI eqs entrypoints over RCU Date: Tue, 28 Jun 2022 15:16:09 +0200 Message-Id: <20220628131619.2109651-11-frederic@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220628131619.2109651-1-frederic@kernel.org> References: <20220628131619.2109651-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The RCU dynticks counter is going to be merged into the context tracking subsystem. Prepare with moving the NMI extended quiescent states entrypoints to context tracking. For now those are dumb redirection to existing RCU calls. Acked-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Neeraj Upadhyay Cc: Uladzislau Rezki Cc: Joel Fernandes Cc: Boqun Feng Cc: Nicolas Saenz Julienne Cc: Marcelo Tosatti Cc: Xiongfeng Wang Cc: Yu Liao Cc: Phil Auld Cc: Paul Gortmaker Cc: Alex Belits Signed-off-by: Paul E. McKenney Reviewed-by: Nicolas Saenz Julienne Tested-by: Nicolas Saenz Julienne --- Documentation/RCU/Design/Requirements/Requirements.rst | 2 +- arch/Kconfig | 2 +- arch/arm64/kernel/entry-common.c | 8 ++++---- include/linux/context_tracking_irq.h | 4 ++++ include/linux/hardirq.h | 4 ++-- kernel/context_tracking.c | 10 ++++++++++ kernel/entry/common.c | 4 ++-- kernel/extable.c | 4 ++-- kernel/trace/trace.c | 2 +- 9 files changed, 27 insertions(+), 13 deletions(-) diff --git a/Documentation/RCU/Design/Requirements/Requirements.rst b/Documentation/RCU/Design/Requirements/Requirements.rst index 074810c73936..a0f8164c8513 100644 --- a/Documentation/RCU/Design/Requirements/Requirements.rst +++ b/Documentation/RCU/Design/Requirements/Requirements.rst @@ -1847,7 +1847,7 @@ normal interrupts. One way that this can happen is for code that directly invokes ct_irq_enter() and ct_irq_exit() to be called from an NMI handler. This astonishing fact of life prompted the current code structure, which has ct_irq_enter() invoking -rcu_nmi_enter() and ct_irq_exit() invoking rcu_nmi_exit(). +ct_nmi_enter() and ct_irq_exit() invoking ct_nmi_exit(). And yes, I also learned of this requirement the hard way. Loadable Modules diff --git a/arch/Kconfig b/arch/Kconfig index 342642be105f..f56f7c0e924d 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -797,7 +797,7 @@ config HAVE_CONTEXT_TRACKING_USER_OFFSTACK - Critical entry code isn't preemptible (or better yet: not interruptible). - - No use of RCU read side critical sections, unless rcu_nmi_enter() + - No use of RCU read side critical sections, unless ct_nmi_enter() got called. - No use of instrumentation, unless instrumentation_begin() got called. diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c index 8dabe9ec10f1..c75ca36b4a49 100644 --- a/arch/arm64/kernel/entry-common.c +++ b/arch/arm64/kernel/entry-common.c @@ -161,7 +161,7 @@ static void noinstr arm64_enter_nmi(struct pt_regs *regs) __nmi_enter(); lockdep_hardirqs_off(CALLER_ADDR0); lockdep_hardirq_enter(); - rcu_nmi_enter(); + ct_nmi_enter(); trace_hardirqs_off_finish(); ftrace_nmi_enter(); @@ -182,7 +182,7 @@ static void noinstr arm64_exit_nmi(struct pt_regs *regs) lockdep_hardirqs_on_prepare(); } - rcu_nmi_exit(); + ct_nmi_exit(); lockdep_hardirq_exit(); if (restore) lockdep_hardirqs_on(CALLER_ADDR0); @@ -199,7 +199,7 @@ static void noinstr arm64_enter_el1_dbg(struct pt_regs *regs) regs->lockdep_hardirqs = lockdep_hardirqs_enabled(); lockdep_hardirqs_off(CALLER_ADDR0); - rcu_nmi_enter(); + ct_nmi_enter(); trace_hardirqs_off_finish(); } @@ -218,7 +218,7 @@ static void noinstr arm64_exit_el1_dbg(struct pt_regs *regs) lockdep_hardirqs_on_prepare(); } - rcu_nmi_exit(); + ct_nmi_exit(); if (restore) lockdep_hardirqs_on(CALLER_ADDR0); } diff --git a/include/linux/context_tracking_irq.h b/include/linux/context_tracking_irq.h index 62f62bbd1a50..c50b5670c4a5 100644 --- a/include/linux/context_tracking_irq.h +++ b/include/linux/context_tracking_irq.h @@ -7,11 +7,15 @@ void ct_irq_enter(void); void ct_irq_exit(void); void ct_irq_enter_irqson(void); void ct_irq_exit_irqson(void); +void ct_nmi_enter(void); +void ct_nmi_exit(void); #else static inline void ct_irq_enter(void) { } static inline void ct_irq_exit(void) { } static inline void ct_irq_enter_irqson(void) { } static inline void ct_irq_exit_irqson(void) { } +static inline void ct_nmi_enter(void) { } +static inline void ct_nmi_exit(void) { } #endif #endif diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index 76878b357ffa..345cdbe9c1b7 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -124,7 +124,7 @@ extern void rcu_nmi_exit(void); do { \ __nmi_enter(); \ lockdep_hardirq_enter(); \ - rcu_nmi_enter(); \ + ct_nmi_enter(); \ instrumentation_begin(); \ ftrace_nmi_enter(); \ instrumentation_end(); \ @@ -143,7 +143,7 @@ extern void rcu_nmi_exit(void); instrumentation_begin(); \ ftrace_nmi_exit(); \ instrumentation_end(); \ - rcu_nmi_exit(); \ + ct_nmi_exit(); \ lockdep_hardirq_exit(); \ __nmi_exit(); \ } while (0) diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c index 72bd71a02c44..b8a731f20778 100644 --- a/kernel/context_tracking.c +++ b/kernel/context_tracking.c @@ -55,6 +55,16 @@ void ct_irq_exit_irqson(void) { rcu_irq_exit_irqson(); } + +noinstr void ct_nmi_enter(void) +{ + rcu_nmi_enter(); +} + +noinstr void ct_nmi_exit(void) +{ + rcu_nmi_exit(); +} #endif /* #ifdef CONFIG_CONTEXT_TRACKING_IDLE */ #ifdef CONFIG_CONTEXT_TRACKING_USER diff --git a/kernel/entry/common.c b/kernel/entry/common.c index 667ba5d581ff..063068a9ea9b 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -449,7 +449,7 @@ irqentry_state_t noinstr irqentry_nmi_enter(struct pt_regs *regs) __nmi_enter(); lockdep_hardirqs_off(CALLER_ADDR0); lockdep_hardirq_enter(); - rcu_nmi_enter(); + ct_nmi_enter(); instrumentation_begin(); trace_hardirqs_off_finish(); @@ -469,7 +469,7 @@ void noinstr irqentry_nmi_exit(struct pt_regs *regs, irqentry_state_t irq_state) } instrumentation_end(); - rcu_nmi_exit(); + ct_nmi_exit(); lockdep_hardirq_exit(); if (irq_state.lockdep) lockdep_hardirqs_on(CALLER_ADDR0); diff --git a/kernel/extable.c b/kernel/extable.c index bda5e9761541..71f482581cab 100644 --- a/kernel/extable.c +++ b/kernel/extable.c @@ -114,7 +114,7 @@ int kernel_text_address(unsigned long addr) /* Treat this like an NMI as it can happen anywhere */ if (no_rcu) - rcu_nmi_enter(); + ct_nmi_enter(); if (is_module_text_address(addr)) goto out; @@ -127,7 +127,7 @@ int kernel_text_address(unsigned long addr) ret = 0; out: if (no_rcu) - rcu_nmi_exit(); + ct_nmi_exit(); return ret; } diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index fe78a6818126..5fc7f17f5ec7 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3105,7 +3105,7 @@ void __trace_stack(struct trace_array *tr, unsigned int trace_ctx, } /* - * When an NMI triggers, RCU is enabled via rcu_nmi_enter(), + * When an NMI triggers, RCU is enabled via ct_nmi_enter(), * but if the above rcu_is_watching() failed, then the NMI * triggered someplace critical, and ct_irq_enter() should * not be called from NMI. -- 2.25.1