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=-5.7 required=3.0 tests=DATE_IN_PAST_03_06, DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 516D2C2D0DB for ; Wed, 22 Jan 2020 13:21:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1E4DA24693 for ; Wed, 22 Jan 2020 13:21:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579699265; bh=nWWiD5jEnlALudvtWMS1vnhl0X6ByubruA79LrLt6CE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=nrrlOYbyBocuTR8a73HQp4mF3wNy5Ow9a8wGvHmfE8A9tqRpthEqiasw1gJtDcmUm 1hnTGhOe8mkjxjajgcSqd0fkutQ+auO4r0ChXrlXflOyuBd9Gz9ymWfrhKV34tkaPV dWQ4C0AlqwNeAfyIdLXZurOZ5wCyeJ8IGQJW2ucs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730154AbgAVNVE (ORCPT ); Wed, 22 Jan 2020 08:21:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:37536 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730122AbgAVNU7 (ORCPT ); Wed, 22 Jan 2020 08:20:59 -0500 Received: from localhost (unknown [84.241.205.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B59E82468A; Wed, 22 Jan 2020 13:20:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579699258; bh=nWWiD5jEnlALudvtWMS1vnhl0X6ByubruA79LrLt6CE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yCUxls7otRVqCnXdPA7STuOCsALDQ2O4NxZgQlE7QqsByCgrgwHhdAH6uEz3dL6Gq R7j2yIZwmohmfqPGZmo6AGdvyoGveYZJJmifD0Gx6ABtbG3S67XDVhFsoRC6HQ+I06 38M+sobVnd8h/32w10wIlmKXBjzVN4+/phpuYfpk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Arvind Sankar , Ard Biesheuvel , Hans de Goede , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , linux-efi@vger.kernel.org, Ingo Molnar Subject: [PATCH 5.4 072/222] efi/earlycon: Fix write-combine mapping on x86 Date: Wed, 22 Jan 2020 10:27:38 +0100 Message-Id: <20200122092838.874517870@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200122092833.339495161@linuxfoundation.org> References: <20200122092833.339495161@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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 commit d92b54570d24d017d2630e314b525ed792f5aa6c upstream. 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. Signed-off-by: Arvind Sankar Signed-off-by: Ard Biesheuvel Cc: Hans de Goede Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Fixes: 69c1f396f25b ("efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation") Link: https://lkml.kernel.org/r/20191224132909.102540-2-ardb@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- drivers/firmware/efi/earlycon.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) --- a/drivers/firmware/efi/earlycon.c +++ b/drivers/firmware/efi/earlycon.c @@ -17,7 +17,7 @@ static const struct console *earlycon_co 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( 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(str 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;