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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 B45DBC2D0CF for ; Tue, 24 Dec 2019 13:29:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A83720706 for ; Tue, 24 Dec 2019 13:29:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577194187; bh=GazPSS+c6B9Kt3+UlWZWQ/BY8A3l+UHzfQLW+rSPTWk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ZsHe+R0wuv0RgmZTxcA/+flu7uzSXyPUDLTux1T1ZOQLNpIicis4pKPUmeDUiEsA5 kneq8VPdgCcUPergydgdtzmaUzbOOH8tb0qE1ytUmAr0ytvFldptCAZNsr7DPI+5vQ kxG7xj6QA1jaf35bgvLgcX6E2woXgK5yG2SK7sAI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726268AbfLXN3q (ORCPT ); Tue, 24 Dec 2019 08:29:46 -0500 Received: from mail.kernel.org ([198.145.29.99]:58538 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726124AbfLXN3q (ORCPT ); Tue, 24 Dec 2019 08:29:46 -0500 Received: from localhost.localdomain (91-167-84-221.subs.proxad.net [91.167.84.221]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 40B582071E; Tue, 24 Dec 2019 13:29:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577194185; bh=GazPSS+c6B9Kt3+UlWZWQ/BY8A3l+UHzfQLW+rSPTWk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CfPfLMO3jmt87QgxhMjBz86DUJKBk4WOZWfR9x/voHeXFtnK+LJ+HgQhEDo1n1X3J FuSRv3enqdSIk8xtvFSZDtvnUwfdJOEyh6GideQstDaQsSRZc8CgCT2bZIPU8wK5wU exTAzBmNjH+NrglLSwxYGIdHet4USIJChsV6Vz+g= From: Ard Biesheuvel To: linux-efi@vger.kernel.org, Ingo Molnar , Thomas Gleixner Cc: Ard Biesheuvel , linux-kernel@vger.kernel.org, Arvind Sankar , Hans de Goede Subject: [PATCH 1/3] efi/earlycon: Fix write-combine mapping on x86 Date: Tue, 24 Dec 2019 14:29:07 +0100 Message-Id: <20191224132909.102540-2-ardb@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191224132909.102540-1-ardb@kernel.org> References: <20191224132909.102540-1-ardb@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Arvind Sankar On x86, until PAT is initialized, WC translates into UC-. Since we calculate and store pgprot_writecombine(PAGE_KERNEL) when earlycon is initialized, this means we actually use UC- mappings instead of WC mappings, which makes scrolling very slow. Instead store a boolean flag to indicate whether we want to use writeback or write-combine mappings, and recalculate the actual pgprot_t we need on every mapping. Once PAT is initialized, we will start using write-combine mappings, which speeds up the scrolling considerably. Fixes: 69c1f396f25b ("efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation") Signed-off-by: Arvind Sankar Signed-off-by: Ard Biesheuvel --- drivers/firmware/efi/earlycon.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) diff --git a/drivers/firmware/efi/earlycon.c b/drivers/firmware/efi/earlycon.c index d4077db6dc97..5d4f84781aa0 100644 --- a/drivers/firmware/efi/earlycon.c +++ b/drivers/firmware/efi/earlycon.c @@ -17,7 +17,7 @@ static const struct console *earlycon_console __initdata; static const struct font_desc *font; static u32 efi_x, efi_y; static u64 fb_base; -static pgprot_t fb_prot; +static bool fb_wb; static void *efi_fb; /* @@ -33,10 +33,8 @@ static int __init efi_earlycon_remap_fb(void) if (!earlycon_console || !(earlycon_console->flags & CON_ENABLED)) return 0; - if (pgprot_val(fb_prot) == pgprot_val(PAGE_KERNEL)) - efi_fb = memremap(fb_base, screen_info.lfb_size, MEMREMAP_WB); - else - efi_fb = memremap(fb_base, screen_info.lfb_size, MEMREMAP_WC); + efi_fb = memremap(fb_base, screen_info.lfb_size, + fb_wb ? MEMREMAP_WB : MEMREMAP_WC); return efi_fb ? 0 : -ENOMEM; } @@ -53,9 +51,12 @@ late_initcall(efi_earlycon_unmap_fb); static __ref void *efi_earlycon_map(unsigned long start, unsigned long len) { + pgprot_t fb_prot; + if (efi_fb) return efi_fb + start; + fb_prot = fb_wb ? PAGE_KERNEL : pgprot_writecombine(PAGE_KERNEL); return early_memremap_prot(fb_base + start, len, pgprot_val(fb_prot)); } @@ -215,10 +216,7 @@ static int __init efi_earlycon_setup(struct earlycon_device *device, if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) fb_base |= (u64)screen_info.ext_lfb_base << 32; - if (opt && !strcmp(opt, "ram")) - fb_prot = PAGE_KERNEL; - else - fb_prot = pgprot_writecombine(PAGE_KERNEL); + fb_wb = opt && !strcmp(opt, "ram"); si = &screen_info; xres = si->lfb_width; -- 2.20.1