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=-3.6 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 AA643C35646 for ; Fri, 21 Feb 2020 13:52:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 81139208C4 for ; Fri, 21 Feb 2020 13:52:02 +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="YfjBwXrC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728862AbgBUNwB (ORCPT ); Fri, 21 Feb 2020 08:52:01 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:56312 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728510AbgBUNu1 (ORCPT ); Fri, 21 Feb 2020 08:50:27 -0500 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=qSxh1JDkdSLbgxbvFaVDkpxSLx98JO+1nlcRpgGZvVE=; b=YfjBwXrCBIp8elkSrkXmGgkO0V be0yZt35oIwjxbJQNrIuY0o1orNPa9FcfXYhEApIObNUlNEV6O++q7hcnObtLbKFYIKfYAP3DpRym wH2Y40LOpsVAY0stzNHRv7wHgQP58UMS43S1Rv4IL17MHYuKJRx5pMZ6xsIEbKmJLjhTy99tFrR7A XkYcgOfWXzj5lTnZCF5aM6zaf3x7LlslFMUdc1meoCYwxVwS+6ttkjsEFoaXrf2OSonek9ikVVQx+ jiDwlSjw9GXe2DfsPDIDkd0tUiXagB0HDitoGVwmg0MIMsG2h7vfa1GoKHPfvRJcpN9J+MULEFnNB KHzEyCNw==; 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 1j58gt-0000OS-O0; Fri, 21 Feb 2020 13:50:04 +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 86C9930610C; Fri, 21 Feb 2020 14:48:07 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id B43F029B5903E; Fri, 21 Feb 2020 14:50:00 +0100 (CET) Message-Id: <20200221134215.264229755@infradead.org> User-Agent: quilt/0.65 Date: Fri, 21 Feb 2020 14:34:20 +0100 From: Peter Zijlstra To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, rostedt@goodmis.org Cc: peterz@infradead.org, mingo@kernel.org, joel@joelfernandes.org, gregkh@linuxfoundation.org, gustavo@embeddedor.com, tglx@linutronix.de, paulmck@kernel.org, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, luto@kernel.org, tony.luck@intel.com, frederic@kernel.org, dan.carpenter@oracle.com, mhiramat@kernel.org Subject: [PATCH v4 04/27] x86/mce: Delete ist_begin_non_atomic() References: <20200221133416.777099322@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 It is an abomination; and in prepration of removing the whole ist_enter() thing, it needs to go. Convert #MC over to using task_work_add() instead; it will run the same code slightly later, on the return to user path of the same exception. Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/include/asm/traps.h | 2 - arch/x86/kernel/cpu/mce/core.c | 53 +++++++++++++++++++++++------------------ arch/x86/kernel/traps.c | 37 ---------------------------- include/linux/sched.h | 6 ++++ 4 files changed, 36 insertions(+), 62 deletions(-) --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -123,8 +123,6 @@ asmlinkage void smp_irq_move_cleanup_int extern void ist_enter(struct pt_regs *regs); extern void ist_exit(struct pt_regs *regs); -extern void ist_begin_non_atomic(struct pt_regs *regs); -extern void ist_end_non_atomic(void); #ifdef CONFIG_VMAP_STACK void __noreturn handle_stack_overflow(const char *message, --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -42,6 +42,7 @@ #include #include #include +#include #include #include @@ -1084,23 +1085,6 @@ static void mce_clear_state(unsigned lon } } -static int do_memory_failure(struct mce *m) -{ - int flags = MF_ACTION_REQUIRED; - int ret; - - pr_err("Uncorrected hardware memory error in user-access at %llx", m->addr); - if (!(m->mcgstatus & MCG_STATUS_RIPV)) - flags |= MF_MUST_KILL; - ret = memory_failure(m->addr >> PAGE_SHIFT, flags); - if (ret) - pr_err("Memory error not recovered"); - else - set_mce_nospec(m->addr >> PAGE_SHIFT); - return ret; -} - - /* * Cases where we avoid rendezvous handler timeout: * 1) If this CPU is offline. @@ -1202,6 +1186,29 @@ static void __mc_scan_banks(struct mce * *m = *final; } +static void kill_me_now(struct callback_head *ch) +{ + force_sig(SIGBUS); +} + +static void kill_me_maybe(struct callback_head *cb) +{ + struct task_struct *p = container_of(cb, struct task_struct, mce_kill_me); + int flags = MF_ACTION_REQUIRED; + + pr_err("Uncorrected hardware memory error in user-access at %llx", p->mce_addr); + if (!(p->mce_status & MCG_STATUS_RIPV)) + flags |= MF_MUST_KILL; + + if (!memory_failure(p->mce_addr >> PAGE_SHIFT, flags)) { + set_mce_nospec(p->mce_addr >> PAGE_SHIFT); + return; + } + + pr_err("Memory error not recovered"); + kill_me_now(cb); +} + /* * The actual machine check handler. This only handles real * exceptions when something got corrupted coming in through int 18. @@ -1344,13 +1351,13 @@ void do_machine_check(struct pt_regs *re /* Fault was in user mode and we need to take some action */ if ((m.cs & 3) == 3) { - ist_begin_non_atomic(regs); - local_irq_enable(); + current->mce_addr = m.addr; + current->mce_status = m.mcgstatus; + current->mce_kill_me.func = kill_me_maybe; + if (kill_it) + current->mce_kill_me.func = kill_me_now; - if (kill_it || do_memory_failure(&m)) - force_sig(SIGBUS); - local_irq_disable(); - ist_end_non_atomic(); + task_work_add(current, ¤t->mce_kill_me, true); } else { if (!fixup_exception(regs, X86_TRAP_MC, error_code, 0)) mce_panic("Failed kernel mode recovery", &m, msg); --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -117,43 +117,6 @@ void ist_exit(struct pt_regs *regs) rcu_nmi_exit(); } -/** - * ist_begin_non_atomic() - begin a non-atomic section in an IST exception - * @regs: regs passed to the IST exception handler - * - * IST exception handlers normally cannot schedule. As a special - * exception, if the exception interrupted userspace code (i.e. - * user_mode(regs) would return true) and the exception was not - * a double fault, it can be safe to schedule. ist_begin_non_atomic() - * begins a non-atomic section within an ist_enter()/ist_exit() region. - * Callers are responsible for enabling interrupts themselves inside - * the non-atomic section, and callers must call ist_end_non_atomic() - * before ist_exit(). - */ -void ist_begin_non_atomic(struct pt_regs *regs) -{ - BUG_ON(!user_mode(regs)); - - /* - * Sanity check: we need to be on the normal thread stack. This - * will catch asm bugs and any attempt to use ist_preempt_enable - * from double_fault. - */ - BUG_ON(!on_thread_stack()); - - preempt_enable_no_resched(); -} - -/** - * ist_end_non_atomic() - begin a non-atomic section in an IST exception - * - * Ends a non-atomic section started with ist_begin_non_atomic(). - */ -void ist_end_non_atomic(void) -{ - preempt_disable(); -} - int is_valid_bugaddr(unsigned long addr) { unsigned short ud; --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1285,6 +1285,12 @@ struct task_struct { unsigned long prev_lowest_stack; #endif +#ifdef CONFIG_X86_MCE + u64 mce_addr; + u64 mce_status; + struct callback_head mce_kill_me; +#endif + /* * New fields for task_struct should be added above here, so that * they are included in the randomized portion of task_struct.