From patchwork Mon Jan 25 18:38:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 370647 Delivered-To: patch@linaro.org Received: by 2002:a02:a60d:0:0:0:0:0 with SMTP id c13csp5324840jam; Tue, 26 Jan 2021 12:52:26 -0800 (PST) X-Google-Smtp-Source: ABdhPJytd5HVCfgJYh/03bslYUgHaFd9iyKXtZBKOAbrAJCNYaAjaHDVjqUfFOSVe5N8sd7FT5dg X-Received: by 2002:a17:906:3b82:: with SMTP id u2mr4735050ejf.66.1611694346323; Tue, 26 Jan 2021 12:52:26 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1611694346; cv=none; d=google.com; s=arc-20160816; b=J5g5JkbJGtw/mMq7g1C8zQCQ3vX7y7wGTTKY7D/6shHevvdX9YRTnz9bbSapQmfpIM UCXh1XG+n8Waq7CkEDONbqqkBAtD3rOwVM82paLfbGSUO9xDZT3899Gb1IiwwfmsUU+o mxTCXQpMWxF5pmc20HAo+QkmLAe5lJ4DiP0ulbWa6rJk4uR01WxrLLOu5gt4V7Jmx4Nw Q5bEh3Q9NdA5u3ff7AVQaWVRD4Y+GvEV8k6dtFVm0ol7ktAZCD6rEQqxj5lC6Zq93H75 8nt991uFLI/jK4zuWFVJgTfakDEaWLgQzov8CyC7WOZHI4bfOz6j09kPTXTwQqlfDq0w uFqg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :user-agent:references:in-reply-to:message-id:date:subject:cc:to :from:dkim-signature; bh=WjUBmpXc8qiPhI7BLBcwuDWVqEe3vT6vBdmHg85TyK0=; b=lC/tuaZjmvZZDY593iWXTIXSbYzv8VnNN+EfedkxomstNCCCr0qKgHbK3SSBU4JCF2 KSgkK8qB91EknLlm1uTmKQqQNH+K+aq149CUi26bES4ABGubVFw8JxT9S9TPQtJVdX5b YFyfo8+gM1vw1z6Nnp0WuyL3sO/cVyClMwpTkl7POGXkByA0JHa3S2O74MscpzMPY1MR jLstlbYyVMMC6Qg+h0Oh2f+HWY41kBsEo9UqE1qA2nBqctO19OPD84RfwrGJZJ7AUyay f+eWGEmEWMbUKkdE1IAq0m6f9JRAfEA9sdlPXllnOUobM04Mndd/Yxwm5MFWGnv4yek3 tBJA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b="JLTMsNw/"; spf=pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id d18si7226800edu.101.2021.01.26.12.52.26; Tue, 26 Jan 2021 12:52:26 -0800 (PST) Received-SPF: pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b="JLTMsNw/"; spf=pass (google.com: domain of stable-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728207AbhAZFBr (ORCPT + 13 others); Tue, 26 Jan 2021 00:01:47 -0500 Received: from mail.kernel.org ([198.145.29.99]:37502 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731158AbhAYSvj (ORCPT ); Mon, 25 Jan 2021 13:51:39 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8DF552083E; Mon, 25 Jan 2021 18:51:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1611600675; bh=4xlM1I/vK0Zb5Neahpka7frgpb4IyD1ETQ1CY5n6wIE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JLTMsNw/VvlnFb37JjiGsRdGrSKcZsoNnHq4T6TF1nDYAYzXnyLVjopKCnlrczdrs ow5stpSs/1ieuYZf3ace1U10eNTUeEEI7d6ScklWrTZOCIGl4BkeiRSFEe/57t30zR Uq1k2YSfj84vXLI132fDzGSiC9YVzn7/XkSdGZ6s= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mark Rutland , Will Deacon , James Morse , Catalin Marinas , Sasha Levin Subject: [PATCH 5.10 090/199] arm64: entry: remove redundant IRQ flag tracing Date: Mon, 25 Jan 2021 19:38:32 +0100 Message-Id: <20210125183220.070116605@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210125183216.245315437@linuxfoundation.org> References: <20210125183216.245315437@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Mark Rutland [ Upstream commit df06824767cc9a32fbdb0e3d3b7e169292a5b5fe ] All EL0 returns go via ret_to_user(), which masks IRQs and notifies lockdep and tracing before calling into do_notify_resume(). Therefore, there's no need for do_notify_resume() to call trace_hardirqs_off(), and the comment is stale. The call is simply redundant. In ret_to_user() we call exit_to_user_mode(), which notifies lockdep and tracing the IRQs will be enabled in userspace, so there's no need for el0_svc_common() to call trace_hardirqs_on() before returning. Further, at the start of ret_to_user() we call trace_hardirqs_off(), so not only is this redundant, but it is immediately undone. In addition to being redundant, the trace_hardirqs_on() in el0_svc_common() leaves lockdep inconsistent with the hardware state, and is liable to cause issues for any C code or instrumentation between this and the call to trace_hardirqs_off() which undoes it in ret_to_user(). This patch removes the redundant tracing calls and associated stale comments. Fixes: 23529049c684 ("arm64: entry: fix non-NMI user<->kernel transitions") Signed-off-by: Mark Rutland Acked-by: Will Deacon Cc: James Morse Cc: Will Deacon Link: https://lore.kernel.org/r/20210107145310.44616-1-mark.rutland@arm.com Signed-off-by: Catalin Marinas Signed-off-by: Sasha Levin --- arch/arm64/kernel/signal.c | 7 ------- arch/arm64/kernel/syscall.c | 9 +-------- 2 files changed, 1 insertion(+), 15 deletions(-) -- 2.27.0 diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index a8184cad88907..50852992752b0 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -914,13 +914,6 @@ static void do_signal(struct pt_regs *regs) asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags) { - /* - * The assembly code enters us with IRQs off, but it hasn't - * informed the tracing code of that for efficiency reasons. - * Update the trace code with the current status. - */ - trace_hardirqs_off(); - do { /* Check valid user FS if needed */ addr_limit_user_check(); diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index f8f758e4a3064..6fa8cfb8232aa 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -165,15 +165,8 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr, if (!has_syscall_work(flags) && !IS_ENABLED(CONFIG_DEBUG_RSEQ)) { local_daif_mask(); flags = current_thread_info()->flags; - if (!has_syscall_work(flags) && !(flags & _TIF_SINGLESTEP)) { - /* - * We're off to userspace, where interrupts are - * always enabled after we restore the flags from - * the SPSR. - */ - trace_hardirqs_on(); + if (!has_syscall_work(flags) && !(flags & _TIF_SINGLESTEP)) return; - } local_daif_restore(DAIF_PROCCTX); }