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 X-Spam-Level: X-Spam-Status: No, score=-14.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4D896C433E1 for ; Sat, 11 Jul 2020 10:10:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 20E9F2075F for ; Sat, 11 Jul 2020 10:10:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="muEx5Ja6"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="oW1CsFUJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727876AbgGKKKF (ORCPT ); Sat, 11 Jul 2020 06:10:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56022 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726661AbgGKKJ7 (ORCPT ); Sat, 11 Jul 2020 06:09:59 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A80B4C08C5DE; Sat, 11 Jul 2020 03:09:58 -0700 (PDT) Date: Sat, 11 Jul 2020 10:09:56 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1594462197; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UwOF32rRkR2JfqLVlVnNRUU0zt16NU7UYSNiAGrb6nQ=; b=muEx5Ja6kL/iJwQUAdNCvADccwBZYuU0hVjwJ90RY1/gOpVsXCcCL/slrJtRW9MHLIJQ1T x8rno9NEPgdK3iAjv6Vpi+d6Mx3gHuYxBh+1BDpDKNTXpCxfrE5FiQ/1CQhGLJuHwY8+kZ 2pSfqeUlghe44AZ7g3rXDW/31Bx8jcihipa3d11ZC6hpDSZs/sMsWK6ExJuA8SzRHUvbKw kv2qIrYF0N5lVRROfD8+CMrysZmKXwhb48+imJwCqRU+BkEENDolMmfHfi434bGBgUV8Zf rVVI1pQncAYiEVXU7G5s9cuIFmoFqw6SOQO37JCUrf+kkkpRdkhEsLTCI29q+w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1594462197; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UwOF32rRkR2JfqLVlVnNRUU0zt16NU7UYSNiAGrb6nQ=; b=oW1CsFUJudCCzXqU0P93z8R/f/F0quj7WzkhHow+B+YhgapxaiDCAZWW1Oly0LV+oOCj75 /XaOEHPIYFvjIXAQ== From: "tip-bot2 for Peter Zijlstra" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: locking/core] x86/entry: Fix NMI vs IRQ state tracking Cc: "Peter Zijlstra (Intel)" , Ingo Molnar , x86 , LKML In-Reply-To: <20200623083721.216740948@infradead.org> References: <20200623083721.216740948@infradead.org> MIME-Version: 1.0 Message-ID: <159446219664.4006.7079542709989198544.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the locking/core branch of tip: Commit-ID: ba1f2b2eaa2a529dba722507c55ff3d761d325dd Gitweb: https://git.kernel.org/tip/ba1f2b2eaa2a529dba722507c55ff3d761d325dd Author: Peter Zijlstra AuthorDate: Wed, 27 May 2020 15:50:29 +02:00 Committer: Peter Zijlstra CommitterDate: Fri, 10 Jul 2020 12:00:01 +02:00 x86/entry: Fix NMI vs IRQ state tracking While the nmi_enter() users did trace_hardirqs_{off_prepare,on_finish}() there was no matching lockdep_hardirqs_*() calls to complete the picture. Introduce idtentry_{enter,exit}_nmi() to enable proper IRQ state tracking across the NMIs. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Ingo Molnar Link: https://lkml.kernel.org/r/20200623083721.216740948@infradead.org --- arch/x86/entry/common.c | 42 ++++++++++++++++++++++++++++---- arch/x86/include/asm/idtentry.h | 3 ++- arch/x86/kernel/nmi.c | 9 +++---- arch/x86/kernel/traps.c | 17 ++++--------- include/linux/hardirq.h | 28 ++++++++++++++------- 5 files changed, 70 insertions(+), 29 deletions(-) diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index 0521546..63c607d 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -592,7 +592,7 @@ SYSCALL_DEFINE0(ni_syscall) * The return value must be fed into the state argument of * idtentry_exit(). */ -idtentry_state_t noinstr idtentry_enter(struct pt_regs *regs) +noinstr idtentry_state_t idtentry_enter(struct pt_regs *regs) { idtentry_state_t ret = { .exit_rcu = false, @@ -687,7 +687,7 @@ static void idtentry_exit_cond_resched(struct pt_regs *regs, bool may_sched) * Counterpart to idtentry_enter(). The return value of the entry * function must be fed into the @state argument. */ -void noinstr idtentry_exit(struct pt_regs *regs, idtentry_state_t state) +noinstr void idtentry_exit(struct pt_regs *regs, idtentry_state_t state) { lockdep_assert_irqs_disabled(); @@ -731,7 +731,7 @@ void noinstr idtentry_exit(struct pt_regs *regs, idtentry_state_t state) * Invokes enter_from_user_mode() to establish the proper context for * NOHZ_FULL. Otherwise scheduling on exit would not be possible. */ -void noinstr idtentry_enter_user(struct pt_regs *regs) +noinstr void idtentry_enter_user(struct pt_regs *regs) { check_user_regs(regs); enter_from_user_mode(); @@ -749,13 +749,47 @@ void noinstr idtentry_enter_user(struct pt_regs *regs) * * Counterpart to idtentry_enter_user(). */ -void noinstr idtentry_exit_user(struct pt_regs *regs) +noinstr void idtentry_exit_user(struct pt_regs *regs) { lockdep_assert_irqs_disabled(); prepare_exit_to_usermode(regs); } +noinstr bool idtentry_enter_nmi(struct pt_regs *regs) +{ + bool irq_state = lockdep_hardirqs_enabled(current); + + __nmi_enter(); + lockdep_hardirqs_off(CALLER_ADDR0); + lockdep_hardirq_enter(); + rcu_nmi_enter(); + + instrumentation_begin(); + trace_hardirqs_off_finish(); + ftrace_nmi_enter(); + instrumentation_end(); + + return irq_state; +} + +noinstr void idtentry_exit_nmi(struct pt_regs *regs, bool restore) +{ + instrumentation_begin(); + ftrace_nmi_exit(); + if (restore) { + trace_hardirqs_on_prepare(); + lockdep_hardirqs_on_prepare(CALLER_ADDR0); + } + instrumentation_end(); + + rcu_nmi_exit(); + lockdep_hardirq_exit(); + if (restore) + lockdep_hardirqs_on(CALLER_ADDR0); + __nmi_exit(); +} + #ifdef CONFIG_XEN_PV #ifndef CONFIG_PREEMPTION /* diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h index 7227225..2b04974 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -20,6 +20,9 @@ typedef struct idtentry_state { idtentry_state_t idtentry_enter(struct pt_regs *regs); void idtentry_exit(struct pt_regs *regs, idtentry_state_t state); +bool idtentry_enter_nmi(struct pt_regs *regs); +void idtentry_exit_nmi(struct pt_regs *regs, bool irq_state); + /** * DECLARE_IDTENTRY - Declare functions for simple IDT entry points * No error code pushed by hardware diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index d7c5e44..4fc9954 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -330,7 +330,6 @@ static noinstr void default_do_nmi(struct pt_regs *regs) __this_cpu_write(last_nmi_rip, regs->ip); instrumentation_begin(); - trace_hardirqs_off_finish(); handled = nmi_handle(NMI_LOCAL, regs); __this_cpu_add(nmi_stats.normal, handled); @@ -417,8 +416,6 @@ static noinstr void default_do_nmi(struct pt_regs *regs) unknown_nmi_error(reason, regs); out: - if (regs->flags & X86_EFLAGS_IF) - trace_hardirqs_on_prepare(); instrumentation_end(); } @@ -478,6 +475,8 @@ static DEFINE_PER_CPU(unsigned long, nmi_dr7); DEFINE_IDTENTRY_RAW(exc_nmi) { + bool irq_state; + if (IS_ENABLED(CONFIG_SMP) && arch_cpu_is_offline(smp_processor_id())) return; @@ -491,14 +490,14 @@ nmi_restart: this_cpu_write(nmi_dr7, local_db_save()); - nmi_enter(); + irq_state = idtentry_enter_nmi(regs); inc_irq_stat(__nmi_count); if (!ignore_nmis) default_do_nmi(regs); - nmi_exit(); + idtentry_exit_nmi(regs, irq_state); local_db_restore(this_cpu_read(nmi_dr7)); diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 4627f82..cdd7382 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -403,7 +403,7 @@ DEFINE_IDTENTRY_DF(exc_double_fault) } #endif - nmi_enter(); + idtentry_enter_nmi(regs); instrumentation_begin(); notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV); @@ -649,15 +649,12 @@ DEFINE_IDTENTRY_RAW(exc_int3) instrumentation_end(); idtentry_exit_user(regs); } else { - nmi_enter(); + bool irq_state = idtentry_enter_nmi(regs); instrumentation_begin(); - trace_hardirqs_off_finish(); if (!do_int3(regs)) die("int3", regs, 0); - if (regs->flags & X86_EFLAGS_IF) - trace_hardirqs_on_prepare(); instrumentation_end(); - nmi_exit(); + idtentry_exit_nmi(regs, irq_state); } } @@ -865,9 +862,8 @@ out: static __always_inline void exc_debug_kernel(struct pt_regs *regs, unsigned long dr6) { - nmi_enter(); + bool irq_state = idtentry_enter_nmi(regs); instrumentation_begin(); - trace_hardirqs_off_finish(); /* * If something gets miswired and we end up here for a user mode @@ -884,10 +880,8 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs, handle_debug(regs, dr6, false); - if (regs->flags & X86_EFLAGS_IF) - trace_hardirqs_on_prepare(); instrumentation_end(); - nmi_exit(); + idtentry_exit_nmi(regs, irq_state); } static __always_inline void exc_debug_user(struct pt_regs *regs, @@ -903,6 +897,7 @@ static __always_inline void exc_debug_user(struct pt_regs *regs, instrumentation_begin(); handle_debug(regs, dr6, true); + instrumentation_end(); idtentry_exit_user(regs); } diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index 03c9fec..754f67a 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -111,32 +111,42 @@ extern void rcu_nmi_exit(void); /* * nmi_enter() can nest up to 15 times; see NMI_BITS. */ -#define nmi_enter() \ +#define __nmi_enter() \ do { \ + lockdep_off(); \ arch_nmi_enter(); \ printk_nmi_enter(); \ - lockdep_off(); \ BUG_ON(in_nmi() == NMI_MASK); \ __preempt_count_add(NMI_OFFSET + HARDIRQ_OFFSET); \ - rcu_nmi_enter(); \ + } while (0) + +#define nmi_enter() \ + do { \ + __nmi_enter(); \ lockdep_hardirq_enter(); \ + rcu_nmi_enter(); \ instrumentation_begin(); \ ftrace_nmi_enter(); \ instrumentation_end(); \ } while (0) +#define __nmi_exit() \ + do { \ + BUG_ON(!in_nmi()); \ + __preempt_count_sub(NMI_OFFSET + HARDIRQ_OFFSET); \ + printk_nmi_exit(); \ + arch_nmi_exit(); \ + lockdep_on(); \ + } while (0) + #define nmi_exit() \ do { \ instrumentation_begin(); \ ftrace_nmi_exit(); \ instrumentation_end(); \ - lockdep_hardirq_exit(); \ rcu_nmi_exit(); \ - BUG_ON(!in_nmi()); \ - __preempt_count_sub(NMI_OFFSET + HARDIRQ_OFFSET); \ - lockdep_on(); \ - printk_nmi_exit(); \ - arch_nmi_exit(); \ + lockdep_hardirq_exit(); \ + __nmi_exit(); \ } while (0) #endif /* LINUX_HARDIRQ_H */