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efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation

Browse Source 
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>
This commit is contained in:
Ard Biesheuvel 2019-02-02 10:41:18 +01:00 committed by Ingo Molnar
parent ce9084ba0d
commit 69c1f396f2
9 changed files with 220 additions and 257 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
Documentation/admin-guide/kernel-parameters.txt
View File

@ -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]]

10
arch/x86/Kconfig.debug
View File

@ -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

1
arch/x86/include/asm/efi.h
View File

@ -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);

4
arch/x86/kernel/early_printk.c
View File

@ -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);

1
arch/x86/platform/efi/Makefile
View File

@ -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

240
arch/x86/platform/efi/early_printk.c
View File

@ -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,
};

6
drivers/firmware/efi/Kconfig
View File

@ -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

1
drivers/firmware/efi/Makefile
View File

@ -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

206
drivers/firmware/efi/earlycon.c Normal file
View File

@ -0,0 +1,206 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2013 Intel Corporation; author Matt Fleming
*/
#include <linux/console.h>
#include <linux/efi.h>
#include <linux/font.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/serial_core.h>
#include <linux/screen_info.h>
#include <asm/early_ioremap.h>
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);