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 <ard.biesheuvel@linaro.org>
Reviewed-by: Alexander Graf <agraf@suse.de>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Jeffrey Hugo <jhugo@codeaurora.org>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20190202094119.13230-10-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 0 insertions, 241 deletions

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 <linux/console.h>
-#include <linux/efi.h>
-#include <linux/font.h>
-#include <linux/io.h>
-#include <linux/kernel.h>
-#include <asm/setup.h>
-
-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,
-};