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=-11.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 1155AC433DF for ; Sat, 30 May 2020 09:58:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D956F208E4 for ; Sat, 30 May 2020 09:57:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728897AbgE3J5V (ORCPT ); Sat, 30 May 2020 05:57:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52890 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728714AbgE3J5T (ORCPT ); Sat, 30 May 2020 05:57:19 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2AE02C03E969; Sat, 30 May 2020 02:57:19 -0700 (PDT) Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jeyEv-0002ou-F6; Sat, 30 May 2020 11:57:17 +0200 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 138D11C032F; Sat, 30 May 2020 11:57:17 +0200 (CEST) Date: Sat, 30 May 2020 09:57:16 -0000 From: "tip-bot2 for Thomas Gleixner" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/entry] x86/idt: Add comments about early #PF handling Cc: Thomas Gleixner , x86 , LKML In-Reply-To: <20200528145522.807135882@linutronix.de> References: <20200528145522.807135882@linutronix.de> MIME-Version: 1.0 Message-ID: <159083263692.17951.2671790138858000362.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 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 x86/entry branch of tip: Commit-ID: 66d2e706c0cecd09b1f3de4844574d30e5469c28 Gitweb: https://git.kernel.org/tip/66d2e706c0cecd09b1f3de4844574d30e5469c28 Author: Thomas Gleixner AuthorDate: Thu, 28 May 2020 16:53:17 +02:00 Committer: Thomas Gleixner CommitterDate: Sat, 30 May 2020 11:50:11 +02:00 x86/idt: Add comments about early #PF handling The difference between 32 and 64 bit vs. early #PF handling is not documented. Replace the FIXME at idt_setup_early_pf() with proper comments. Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20200528145522.807135882@linutronix.de --- arch/x86/kernel/idt.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c index 4b99f7b..5ef82fc 100644 --- a/arch/x86/kernel/idt.c +++ b/arch/x86/kernel/idt.c @@ -61,7 +61,11 @@ static bool idt_setup_done __initdata; static const __initconst struct idt_data early_idts[] = { INTG(X86_TRAP_DB, asm_exc_debug), SYSG(X86_TRAP_BP, asm_exc_int3), + #ifdef CONFIG_X86_32 + /* + * Not possible on 64-bit. See idt_setup_early_pf() for details. + */ INTG(X86_TRAP_PF, asm_exc_page_fault), #endif }; @@ -256,8 +260,10 @@ void __init idt_setup_traps(void) * cpu_init() is invoked and sets up TSS. The IST variant is installed * after that. * - * FIXME: Why is 32bit and 64bit installing the PF handler at different - * places in the early setup code? + * Note, that X86_64 cannot install the real #PF handler in + * idt_setup_early_traps() because the memory intialization needs the #PF + * handler from the early_idt_handler_array to initialize the early page + * tables. */ void __init idt_setup_early_pf(void) {