Received: by 2002:ac0:8c9a:0:0:0:0:0 with SMTP id r26csp3545775ima; Mon, 4 Feb 2019 00:48:42 -0800 (PST) X-Google-Smtp-Source: AHgI3IZ37VWpeVAm0PCEH649LAm5ocsKUGudSlsGBZw/sIYZB5xcVNy/lH5v2XqKHPfXkM7SfMNr X-Received: by 2002:a63:5107:: with SMTP id f7mr11745031pgb.218.1549270122641; Mon, 04 Feb 2019 00:48:42 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1549270122; cv=none; d=google.com; s=arc-20160816; b=VhRK8JWrcR763Lvg+IFIH4Vot+GbhOwcFa7i6WUDcJtWZcckNkJnUehYwKX0bY+njr NpsdPoNJqw85vtlwV9rWruBcnGFwYzpKVW9mTcfDWz336itA8s94IdG334ouudcCfBrJ 8eDkfMQfoT31UVAI3OnHagznFVHgo/8dUY/C5mAkGD1Xu5NHTqe4UT9pAHNcXpDpBfFT pqSER9p6jtF3BHzOrH914PiIEc0jWpuIZKU517tZYXEaLd5vh2FkW9W8Sqf6N1DeigD2 hUcMsyRD8lkvDx9LMLjZW0KU7smYqId+eC64s0ix90qaPdXAJ+z3niuILHhsTCwY9S1Z Bmnw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-disposition :content-transfer-encoding:mime-version:robot-unsubscribe:robot-id :git-commit-id:subject:to:references:in-reply-to:reply-to:cc :message-id:from:date; bh=SjPRujbcJJPtEj6usIdXHJUQrRkyiyd6NHTe1deW6IM=; b=pEVywq+b6XI+jhJ9rg/blAQVjIdj4ICo9TMSsscNxx4WRJTDa9XVbEOW2JRqqZdKNn zWjA27d4C9/mGlEDxcJdwb86LsCBoFHJJwS5trREZbL6Z4OIoxnxxdRS5v6aD1h+b9Kb HPRZ4KjflyMbhBqUEivSPhMfXjv9LoiufHeufiHNQ3gXIn08l4koagCAI/vfaNfyeirA E6QkSaaMVtl09KCZtaC0lnPUrWzBKf5Vrd2ckiqZkDCJpLl7JKwmNG9IIvjtSWoqL954 gT3ouJLcLrxAeYlH3PCzFUuh6/4jdE8iR+ieFrMSSxq7/Z8zyPWPJYIhVGUW8JT6DCVP eWlA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id t136si11486653pfc.262.2019.02.04.00.48.27; Mon, 04 Feb 2019 00:48:42 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728430AbfBDIra (ORCPT + 99 others); Mon, 4 Feb 2019 03:47:30 -0500 Received: from terminus.zytor.com ([198.137.202.136]:39537 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727092AbfBDIra (ORCPT ); Mon, 4 Feb 2019 03:47:30 -0500 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id x148kr4g356609 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Mon, 4 Feb 2019 00:46:53 -0800 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id x148kqMR356606; Mon, 4 Feb 2019 00:46:52 -0800 Date: Mon, 4 Feb 2019 00:46:52 -0800 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Ard Biesheuvel Message-ID: Cc: pjones@redhat.com, agraf@suse.de, xypron.glpk@gmx.de, torvalds@linux-foundation.org, leif.lindholm@linaro.org, sai.praneeth.prakhya@intel.com, mingo@kernel.org, takahiro.akashi@linaro.org, peterz@infradead.org, hpa@zytor.com, tglx@linutronix.de, bp@alien8.de, linux-kernel@vger.kernel.org, bjorn.andersson@linaro.org, jhugo@codeaurora.org, lee.jones@linaro.org, ard.biesheuvel@linaro.org, matt@codeblueprint.co.uk Reply-To: linux-kernel@vger.kernel.org, bp@alien8.de, tglx@linutronix.de, hpa@zytor.com, peterz@infradead.org, takahiro.akashi@linaro.org, matt@codeblueprint.co.uk, ard.biesheuvel@linaro.org, lee.jones@linaro.org, bjorn.andersson@linaro.org, jhugo@codeaurora.org, sai.praneeth.prakhya@intel.com, torvalds@linux-foundation.org, leif.lindholm@linaro.org, xypron.glpk@gmx.de, agraf@suse.de, pjones@redhat.com, mingo@kernel.org In-Reply-To: <20190202094119.13230-10-ard.biesheuvel@linaro.org> References: <20190202094119.13230-10-ard.biesheuvel@linaro.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:efi/core] efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation Git-Commit-ID: 69c1f396f25b805aeff08f06d2e992c315ee5b1e X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Spam-Status: No, score=-0.8 required=5.0 tests=ALL_TRUSTED,BAYES_00, FREEMAIL_FORGED_REPLYTO,T_DATE_IN_FUTURE_96_Q autolearn=no autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on terminus.zytor.com Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 69c1f396f25b805aeff08f06d2e992c315ee5b1e Gitweb: https://git.kernel.org/tip/69c1f396f25b805aeff08f06d2e992c315ee5b1e Author: Ard Biesheuvel AuthorDate: Sat, 2 Feb 2019 10:41:18 +0100 Committer: Ingo Molnar CommitDate: Mon, 4 Feb 2019 08:27:30 +0100 efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation Move the x86 EFI earlyprintk implementation to a shared location under drivers/firmware and tweak it slightly so we can expose it as an earlycon implementation (which is generic) rather than earlyprintk (which is only implemented for a few architectures) This also involves switching to write-combine mappings by default (which is required on ARM since device mappings lack memory semantics, and so memcpy/memset may not be used on them), and adding support for shared memory framebuffers on cache coherent non-x86 systems (which do not tolerate mismatched attributes). Note that 32-bit ARM does not populate its struct screen_info early enough for earlycon=efifb to work, so it is disabled there. Signed-off-by: Ard Biesheuvel Reviewed-by: Alexander Graf Cc: AKASHI Takahiro Cc: Bjorn Andersson Cc: Borislav Petkov Cc: Heinrich Schuchardt Cc: Jeffrey Hugo Cc: Lee Jones Cc: Leif Lindholm Cc: Linus Torvalds Cc: Matt Fleming Cc: Peter Jones Cc: Peter Zijlstra Cc: Sai Praneeth Prakhya Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20190202094119.13230-10-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar --- Documentation/admin-guide/kernel-parameters.txt | 8 +- arch/x86/Kconfig.debug | 10 - arch/x86/include/asm/efi.h | 1 - arch/x86/kernel/early_printk.c | 4 - arch/x86/platform/efi/Makefile | 1 - arch/x86/platform/efi/early_printk.c | 240 ------------------------ drivers/firmware/efi/Kconfig | 6 + drivers/firmware/efi/Makefile | 1 + drivers/firmware/efi/earlycon.c | 206 ++++++++++++++++++++ 9 files changed, 220 insertions(+), 257 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index b799bcf67d7b..76dd3baa31e0 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1073,9 +1073,15 @@ specified address. The serial port must already be setup and configured. Options are not yet supported. + efifb,[options] + Start an early, unaccelerated console on the EFI + memory mapped framebuffer (if available). On cache + coherent non-x86 systems that use system memory for + the framebuffer, pass the 'ram' option so that it is + mapped with the correct attributes. + earlyprintk= [X86,SH,ARM,M68k,S390] earlyprintk=vga - earlyprintk=efi earlyprintk=sclp earlyprintk=xen earlyprintk=serial[,ttySn[,baudrate]] diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 0723dff17e6c..15d0fbe27872 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -40,16 +40,6 @@ config EARLY_PRINTK_DBGP with klogd/syslogd or the X server. You should normally say N here, unless you want to debug such a crash. You need usb debug device. -config EARLY_PRINTK_EFI - bool "Early printk via the EFI framebuffer" - depends on EFI && EARLY_PRINTK - select FONT_SUPPORT - ---help--- - Write kernel log output directly into the EFI framebuffer. - - This is useful for kernel debugging when your machine crashes very - early before the console code is initialized. - config EARLY_PRINTK_USB_XDBC bool "Early printk via the xHCI debug port" depends on EARLY_PRINTK && PCI diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index 107283b1eb1e..606a4b6a9812 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -170,7 +170,6 @@ static inline bool efi_runtime_supported(void) return false; } -extern struct console early_efi_console; extern void parse_efi_setup(u64 phys_addr, u32 data_len); extern void efifb_setup_from_dmi(struct screen_info *si, const char *opt); diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c index 374a52fa5296..9b33904251a9 100644 --- a/arch/x86/kernel/early_printk.c +++ b/arch/x86/kernel/early_printk.c @@ -388,10 +388,6 @@ static int __init setup_early_printk(char *buf) if (!strncmp(buf, "xen", 3)) early_console_register(&xenboot_console, keep); #endif -#ifdef CONFIG_EARLY_PRINTK_EFI - if (!strncmp(buf, "efi", 3)) - early_console_register(&early_efi_console, keep); -#endif #ifdef CONFIG_EARLY_PRINTK_USB_XDBC if (!strncmp(buf, "xdbc", 4)) early_xdbc_parse_parameter(buf + 4); diff --git a/arch/x86/platform/efi/Makefile b/arch/x86/platform/efi/Makefile index e4dc3862d423..fe29f3f5d384 100644 --- a/arch/x86/platform/efi/Makefile +++ b/arch/x86/platform/efi/Makefile @@ -3,5 +3,4 @@ OBJECT_FILES_NON_STANDARD_efi_thunk_$(BITS).o := y OBJECT_FILES_NON_STANDARD_efi_stub_$(BITS).o := y obj-$(CONFIG_EFI) += quirks.o efi.o efi_$(BITS).o efi_stub_$(BITS).o -obj-$(CONFIG_EARLY_PRINTK_EFI) += early_printk.o obj-$(CONFIG_EFI_MIXED) += efi_thunk_$(BITS).o diff --git a/arch/x86/platform/efi/early_printk.c b/arch/x86/platform/efi/early_printk.c deleted file mode 100644 index 7138bc7a265c..000000000000 --- a/arch/x86/platform/efi/early_printk.c +++ /dev/null @@ -1,240 +0,0 @@ -/* - * Copyright (C) 2013 Intel Corporation; author Matt Fleming - * - * This file is part of the Linux kernel, and is made available under - * the terms of the GNU General Public License version 2. - */ - -#include -#include -#include -#include -#include -#include - -static const struct font_desc *font; -static u32 efi_x, efi_y; -static void *efi_fb; -static bool early_efi_keep; - -/* - * efi earlyprintk need use early_ioremap to map the framebuffer. - * But early_ioremap is not usable for earlyprintk=efi,keep, ioremap should - * be used instead. ioremap will be available after paging_init() which is - * earlier than initcall callbacks. Thus adding this early initcall function - * early_efi_map_fb to map the whole efi framebuffer. - */ -static __init int early_efi_map_fb(void) -{ - u64 base, size; - - if (!early_efi_keep) - return 0; - - base = boot_params.screen_info.lfb_base; - if (boot_params.screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) - base |= (u64)boot_params.screen_info.ext_lfb_base << 32; - size = boot_params.screen_info.lfb_size; - efi_fb = ioremap(base, size); - - return efi_fb ? 0 : -ENOMEM; -} -early_initcall(early_efi_map_fb); - -/* - * early_efi_map maps efi framebuffer region [start, start + len -1] - * In case earlyprintk=efi,keep we have the whole framebuffer mapped already - * so just return the offset efi_fb + start. - */ -static __ref void *early_efi_map(unsigned long start, unsigned long len) -{ - u64 base; - - base = boot_params.screen_info.lfb_base; - if (boot_params.screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) - base |= (u64)boot_params.screen_info.ext_lfb_base << 32; - - if (efi_fb) - return (efi_fb + start); - else - return early_ioremap(base + start, len); -} - -static __ref void early_efi_unmap(void *addr, unsigned long len) -{ - if (!efi_fb) - early_iounmap(addr, len); -} - -static void early_efi_clear_scanline(unsigned int y) -{ - unsigned long *dst; - u16 len; - - len = boot_params.screen_info.lfb_linelength; - dst = early_efi_map(y*len, len); - if (!dst) - return; - - memset(dst, 0, len); - early_efi_unmap(dst, len); -} - -static void early_efi_scroll_up(void) -{ - unsigned long *dst, *src; - u16 len; - u32 i, height; - - len = boot_params.screen_info.lfb_linelength; - height = boot_params.screen_info.lfb_height; - - for (i = 0; i < height - font->height; i++) { - dst = early_efi_map(i*len, len); - if (!dst) - return; - - src = early_efi_map((i + font->height) * len, len); - if (!src) { - early_efi_unmap(dst, len); - return; - } - - memmove(dst, src, len); - - early_efi_unmap(src, len); - early_efi_unmap(dst, len); - } -} - -static void early_efi_write_char(u32 *dst, unsigned char c, unsigned int h) -{ - const u32 color_black = 0x00000000; - const u32 color_white = 0x00ffffff; - const u8 *src; - u8 s8; - int m; - - src = font->data + c * font->height; - s8 = *(src + h); - - for (m = 0; m < 8; m++) { - if ((s8 >> (7 - m)) & 1) - *dst = color_white; - else - *dst = color_black; - dst++; - } -} - -static void -early_efi_write(struct console *con, const char *str, unsigned int num) -{ - struct screen_info *si; - unsigned int len; - const char *s; - void *dst; - - si = &boot_params.screen_info; - len = si->lfb_linelength; - - while (num) { - unsigned int linemax; - unsigned int h, count = 0; - - for (s = str; *s && *s != '\n'; s++) { - if (count == num) - break; - count++; - } - - linemax = (si->lfb_width - efi_x) / font->width; - if (count > linemax) - count = linemax; - - for (h = 0; h < font->height; h++) { - unsigned int n, x; - - dst = early_efi_map((efi_y + h) * len, len); - if (!dst) - return; - - s = str; - n = count; - x = efi_x; - - while (n-- > 0) { - early_efi_write_char(dst + x*4, *s, h); - x += font->width; - s++; - } - - early_efi_unmap(dst, len); - } - - num -= count; - efi_x += count * font->width; - str += count; - - if (num > 0 && *s == '\n') { - efi_x = 0; - efi_y += font->height; - str++; - num--; - } - - if (efi_x + font->width > si->lfb_width) { - efi_x = 0; - efi_y += font->height; - } - - if (efi_y + font->height > si->lfb_height) { - u32 i; - - efi_y -= font->height; - early_efi_scroll_up(); - - for (i = 0; i < font->height; i++) - early_efi_clear_scanline(efi_y + i); - } - } -} - -static __init int early_efi_setup(struct console *con, char *options) -{ - struct screen_info *si; - u16 xres, yres; - u32 i; - - si = &boot_params.screen_info; - xres = si->lfb_width; - yres = si->lfb_height; - - /* - * early_efi_write_char() implicitly assumes a framebuffer with - * 32-bits per pixel. - */ - if (si->lfb_depth != 32) - return -ENODEV; - - font = get_default_font(xres, yres, -1, -1); - if (!font) - return -ENODEV; - - efi_y = rounddown(yres, font->height) - font->height; - for (i = 0; i < (yres - efi_y) / font->height; i++) - early_efi_scroll_up(); - - /* early_console_register will unset CON_BOOT in case ,keep */ - if (!(con->flags & CON_BOOT)) - early_efi_keep = true; - return 0; -} - -struct console early_efi_console = { - .name = "earlyefi", - .write = early_efi_write, - .setup = early_efi_setup, - .flags = CON_PRINTBUFFER, - .index = -1, -}; diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig index 89110dfc7127..190be0b1d109 100644 --- a/drivers/firmware/efi/Kconfig +++ b/drivers/firmware/efi/Kconfig @@ -198,3 +198,9 @@ config EFI_DEV_PATH_PARSER bool depends on ACPI default n + +config EFI_EARLYCON + def_bool y + depends on SERIAL_EARLYCON && !ARM && !IA64 + select FONT_SUPPORT + select ARCH_USE_MEMREMAP_PROT diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile index 5f9f5039de50..d2d0d2030620 100644 --- a/drivers/firmware/efi/Makefile +++ b/drivers/firmware/efi/Makefile @@ -30,5 +30,6 @@ arm-obj-$(CONFIG_EFI) := arm-init.o arm-runtime.o obj-$(CONFIG_ARM) += $(arm-obj-y) obj-$(CONFIG_ARM64) += $(arm-obj-y) obj-$(CONFIG_EFI_CAPSULE_LOADER) += capsule-loader.o +obj-$(CONFIG_EFI_EARLYCON) += earlycon.o obj-$(CONFIG_UEFI_CPER_ARM) += cper-arm.o obj-$(CONFIG_UEFI_CPER_X86) += cper-x86.o diff --git a/drivers/firmware/efi/earlycon.c b/drivers/firmware/efi/earlycon.c new file mode 100644 index 000000000000..c9a0efca17b0 --- /dev/null +++ b/drivers/firmware/efi/earlycon.c @@ -0,0 +1,206 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2013 Intel Corporation; author Matt Fleming + */ + +#include +#include +#include +#include +#include +#include +#include + +#include + +static const struct font_desc *font; +static u32 efi_x, efi_y; +static u64 fb_base; +static pgprot_t fb_prot; + +static __ref void *efi_earlycon_map(unsigned long start, unsigned long len) +{ + return early_memremap_prot(fb_base + start, len, pgprot_val(fb_prot)); +} + +static __ref void efi_earlycon_unmap(void *addr, unsigned long len) +{ + early_memunmap(addr, len); +} + +static void efi_earlycon_clear_scanline(unsigned int y) +{ + unsigned long *dst; + u16 len; + + len = screen_info.lfb_linelength; + dst = efi_earlycon_map(y*len, len); + if (!dst) + return; + + memset(dst, 0, len); + efi_earlycon_unmap(dst, len); +} + +static void efi_earlycon_scroll_up(void) +{ + unsigned long *dst, *src; + u16 len; + u32 i, height; + + len = screen_info.lfb_linelength; + height = screen_info.lfb_height; + + for (i = 0; i < height - font->height; i++) { + dst = efi_earlycon_map(i*len, len); + if (!dst) + return; + + src = efi_earlycon_map((i + font->height) * len, len); + if (!src) { + efi_earlycon_unmap(dst, len); + return; + } + + memmove(dst, src, len); + + efi_earlycon_unmap(src, len); + efi_earlycon_unmap(dst, len); + } +} + +static void efi_earlycon_write_char(u32 *dst, unsigned char c, unsigned int h) +{ + const u32 color_black = 0x00000000; + const u32 color_white = 0x00ffffff; + const u8 *src; + u8 s8; + int m; + + src = font->data + c * font->height; + s8 = *(src + h); + + for (m = 0; m < 8; m++) { + if ((s8 >> (7 - m)) & 1) + *dst = color_white; + else + *dst = color_black; + dst++; + } +} + +static void +efi_earlycon_write(struct console *con, const char *str, unsigned int num) +{ + struct screen_info *si; + unsigned int len; + const char *s; + void *dst; + + si = &screen_info; + len = si->lfb_linelength; + + while (num) { + unsigned int linemax; + unsigned int h, count = 0; + + for (s = str; *s && *s != '\n'; s++) { + if (count == num) + break; + count++; + } + + linemax = (si->lfb_width - efi_x) / font->width; + if (count > linemax) + count = linemax; + + for (h = 0; h < font->height; h++) { + unsigned int n, x; + + dst = efi_earlycon_map((efi_y + h) * len, len); + if (!dst) + return; + + s = str; + n = count; + x = efi_x; + + while (n-- > 0) { + efi_earlycon_write_char(dst + x*4, *s, h); + x += font->width; + s++; + } + + efi_earlycon_unmap(dst, len); + } + + num -= count; + efi_x += count * font->width; + str += count; + + if (num > 0 && *s == '\n') { + efi_x = 0; + efi_y += font->height; + str++; + num--; + } + + if (efi_x + font->width > si->lfb_width) { + efi_x = 0; + efi_y += font->height; + } + + if (efi_y + font->height > si->lfb_height) { + u32 i; + + efi_y -= font->height; + efi_earlycon_scroll_up(); + + for (i = 0; i < font->height; i++) + efi_earlycon_clear_scanline(efi_y + i); + } + } +} + +static int __init efi_earlycon_setup(struct earlycon_device *device, + const char *opt) +{ + struct screen_info *si; + u16 xres, yres; + u32 i; + + if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI) + return -ENODEV; + + fb_base = screen_info.lfb_base; + 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); + + si = &screen_info; + xres = si->lfb_width; + yres = si->lfb_height; + + /* + * efi_earlycon_write_char() implicitly assumes a framebuffer with + * 32 bits per pixel. + */ + if (si->lfb_depth != 32) + return -ENODEV; + + font = get_default_font(xres, yres, -1, -1); + if (!font) + return -ENODEV; + + efi_y = rounddown(yres, font->height) - font->height; + for (i = 0; i < (yres - efi_y) / font->height; i++) + efi_earlycon_scroll_up(); + + device->con->write = efi_earlycon_write; + return 0; +} +EARLYCON_DECLARE(efifb, efi_earlycon_setup);