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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E115EC433EF for ; Sun, 17 Oct 2021 19:26:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B53D760F9E for ; Sun, 17 Oct 2021 19:26:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344513AbhJQT2b (ORCPT ); Sun, 17 Oct 2021 15:28:31 -0400 Received: from mx-out.tlen.pl ([193.222.135.158]:38792 "EHLO mx-out.tlen.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344499AbhJQT2a (ORCPT ); Sun, 17 Oct 2021 15:28:30 -0400 Received: (wp-smtpd smtp.tlen.pl 16948 invoked from network); 17 Oct 2021 21:26:17 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=o2.pl; s=1024a; t=1634498777; bh=K4x9QhXuKOZkWxOZ1tfZPtZ3zxAXUZxqrJhTrhSSoaM=; h=From:To:Cc:Subject; b=XqGREuta1s0qalf2wmlNmSmRBkx9QEkpQGw1pBKAKrOUnhGwfQLLIqrZmh/jxW4Ug bTFGlybuXKKd5dI4ZpN57/oKiaLMWpfvpwKsThSytV1q21BGNRIhyWylSQNtvac4Aa 8JT4UIgqgyIC7gOxfNOpgdpgFZcSDpGfFLTnmchs= Received: from aaet142.neoplus.adsl.tpnet.pl (HELO localhost.localdomain) (mat.jonczyk@o2.pl@[83.4.123.142]) (envelope-sender ) by smtp.tlen.pl (WP-SMTPD) with SMTP for ; 17 Oct 2021 21:26:17 +0200 From: =?UTF-8?q?Mateusz=20Jo=C5=84czyk?= To: linux-kernel@vger.kernel.org, x86@kernel.org Cc: =?UTF-8?q?Mateusz=20Jo=C5=84czyk?= , Thomas Gleixner , Ingo Molnar , Borislav Petkov Subject: [PATCH RESEND v2] x86: warn on native_io_delay() before DMI scan Date: Sun, 17 Oct 2021 21:25:58 +0200 Message-Id: <20211017192558.266809-1-mat.jonczyk@o2.pl> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-WP-MailID: 14a9d553ccf097e6b09d7531a967c5c6 X-WP-AV: skaner antywirusowy Poczty o2 X-WP-SPAM: NO 0000000 [AQO0] Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Writing to IO port 0x80 in native_io_delay() causes system lockups on some laptops. This is handled by io_delay_init(), which scans DMI info and changes io_delay_type on these laptops. Therefore, calling native_io_delay() / outb_p() / inb_p() / etc. before io_delay_init() may cause problems there and may constitute a kernel bug. Warn if this happens. Signed-off-by: Mateusz Jończyk Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov --- v2: make io_delay_dmi_scanned static arch/x86/kernel/io_delay.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/x86/kernel/io_delay.c b/arch/x86/kernel/io_delay.c index fdb6506ceaaa..d6deca551a5c 100644 --- a/arch/x86/kernel/io_delay.c +++ b/arch/x86/kernel/io_delay.c @@ -29,6 +29,7 @@ #endif int io_delay_type __read_mostly = DEFAULT_IO_DELAY_TYPE; +static int io_delay_dmi_scanned __read_mostly; static int __initdata io_delay_override; @@ -37,6 +38,8 @@ static int __initdata io_delay_override; */ void native_io_delay(void) { + WARN_ON_ONCE(!io_delay_dmi_scanned); + switch (io_delay_type) { default: case IO_DELAY_TYPE_0X80: @@ -123,6 +126,8 @@ void __init io_delay_init(void) { if (!io_delay_override) dmi_check_system(io_delay_0xed_port_dmi_table); + + io_delay_dmi_scanned = 1; } static int __init io_delay_param(char *s) -- 2.25.1