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=-3.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 2F7DDC433E0 for ; Thu, 28 May 2020 14:17:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0BA032075F for ; Thu, 28 May 2020 14:17:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="T4pEPgZD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391058AbgE1ORi (ORCPT ); Thu, 28 May 2020 10:17:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390996AbgE1ORO (ORCPT ); Thu, 28 May 2020 10:17:14 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5EFFFC08C5C7 for ; Thu, 28 May 2020 07:17:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=HhRz+E67wqZLX9Kj0h1J/Z/3Uz9wGLyqpa654HVNs3o=; b=T4pEPgZDlX8IgucK0JkJFDw24W 0ofDvbDK7EJnWjXf3+82n0Iu5O2/uOrPTCTxsm99iQ+qu7MBopvqXZ6k0odtjS9LMtSyAaHUDeRqt qnMVuy/e98JUHcs4Av9BiPkxRVyy/eeBtxOZREn0SRYkbTAUZbruZ0n0FJFhQEGbCD+TGBa5sFvrF ZQT8k/kN92vcwwe6EgdE85cZf/rZN9gsguO7kR8is+Vd1yXto1/SkrORVlSWhAlVlB8Av+ftb/MIv A2fBMhdXgw95P9jp1PA3jkw5gwgQY87dOFuM7rv+g5DzaJ8BkDNhK8oyIyXUIsC0/V/2Oc9W3nND4 PvQcR29w==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jeJLI-0007a4-QT; Thu, 28 May 2020 14:17:09 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 3A24530704D; Thu, 28 May 2020 16:17:07 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id E63002B9FB570; Thu, 28 May 2020 16:17:06 +0200 (CEST) Message-ID: <20200528140947.035164777@infradead.org> User-Agent: quilt/0.66 Date: Thu, 28 May 2020 16:05:41 +0200 From: Peter Zijlstra To: mingo@kernel.org, will@kernel.org, tglx@linutronix.de Cc: x86@kernel.org, linux-kernel@vger.kernel.org, a.darwish@linutronix.de, rostedt@goodmis.org, bigeasy@linutronix.de, peterz@infradead.org Subject: [PATCH v2 6/6] x86/entry: Fix NMI vs IRQ state tracking References: <20200528140535.206916549@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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) --- arch/x86/entry/common.c | 42 ++++++++++++++++++++++++++++++++++++---- arch/x86/include/asm/idtentry.h | 3 ++ arch/x86/kernel/nmi.c | 9 +++----- arch/x86/kernel/traps.c | 20 ++++--------------- include/linux/hardirq.h | 28 ++++++++++++++++++-------- 5 files changed, 69 insertions(+), 33 deletions(-) --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -550,7 +550,7 @@ SYSCALL_DEFINE0(ni_syscall) * The return value must be fed into the rcu_exit argument of * idtentry_exit_cond_rcu(). */ -bool noinstr idtentry_enter_cond_rcu(struct pt_regs *regs) +noinstr bool idtentry_enter_cond_rcu(struct pt_regs *regs) { if (user_mode(regs)) { enter_from_user_mode(); @@ -619,7 +619,7 @@ static void idtentry_exit_cond_resched(s * Counterpart to idtentry_enter_cond_rcu(). The return value of the entry * function must be fed into the @rcu_exit argument. */ -void noinstr idtentry_exit_cond_rcu(struct pt_regs *regs, bool rcu_exit) +noinstr void idtentry_exit_cond_rcu(struct pt_regs *regs, bool rcu_exit) { lockdep_assert_irqs_disabled(); @@ -663,7 +663,7 @@ void noinstr idtentry_exit_cond_rcu(stru * 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) { enter_from_user_mode(); } @@ -680,13 +680,47 @@ void noinstr idtentry_enter_user(struct * * 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(); + + __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 /* --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -16,6 +16,9 @@ void idtentry_exit_user(struct pt_regs * bool idtentry_enter_cond_rcu(struct pt_regs *regs); void idtentry_exit_cond_rcu(struct pt_regs *regs, bool rcu_exit); +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 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -330,7 +330,6 @@ static noinstr void default_do_nmi(struc __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(struc unknown_nmi_error(reason, regs); out: - if (regs->flags & X86_EFLAGS_IF) - trace_hardirqs_on_prepare(); instrumentation_end(); } @@ -511,6 +508,8 @@ static noinstr bool is_debug_stack(unsig DEFINE_IDTENTRY_NMI(exc_nmi) { + bool irq_state; + if (IS_ENABLED(CONFIG_SMP) && cpu_is_offline(smp_processor_id())) return; @@ -535,14 +534,14 @@ DEFINE_IDTENTRY_NMI(exc_nmi) } #endif - 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); #ifdef CONFIG_X86_64 if (unlikely(this_cpu_read(update_debug_stack))) { --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -387,7 +387,7 @@ 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); @@ -632,15 +632,12 @@ 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); } } @@ -852,10 +849,7 @@ static void noinstr handle_debug(struct static __always_inline void exc_debug_kernel(struct pt_regs *regs, unsigned long dr6) { - nmi_enter(); - instrumentation_begin(); - trace_hardirqs_off_finish(); - instrumentation_end(); + bool irq_state = idtentry_enter_nmi(regs); /* * The SDM says "The processor clears the BTF flag when it @@ -878,11 +872,7 @@ static __always_inline void exc_debug_ke if (dr6) handle_debug(regs, dr6, false); - instrumentation_begin(); - 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, --- 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 */