diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 8 | ||||
| -rw-r--r-- | arch/x86/Kconfig.debug | 10 | ||||
| -rw-r--r-- | arch/x86/include/asm/efi.h | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/early_printk.c | 7 | ||||
| -rw-r--r-- | arch/x86/platform/efi/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/platform/efi/early_printk.c | 191 |
6 files changed, 216 insertions, 3 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 7f9d4f53882c..7a0f202d482e 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -792,6 +792,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. earlyprintk= [X86,SH,BLACKFIN,ARM] earlyprintk=vga + earlyprintk=efi earlyprintk=xen earlyprintk=serial[,ttySn[,baudrate]] earlyprintk=serial[,0x...[,baudrate]] @@ -805,7 +806,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Append ",keep" to not disable it when the real console takes over. - Only vga or serial or usb debug port at a time. + Only one of vga, efi, serial, or usb debug port can + be used at a time. Currently only ttyS0 and ttyS1 may be specified by name. Other I/O ports may be explicitly specified @@ -819,8 +821,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Interaction with the standard serial driver is not very good. - The VGA output is eventually overwritten by the real - console. + The VGA and EFI output is eventually overwritten by + the real console. The xen output can only be used by Xen PV guests. diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 78d91afb8e50..0f3621ed1db6 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -59,6 +59,16 @@ config EARLY_PRINTK_DBGP with klogd/syslogd or the X server. You should normally 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 X86_PTDUMP bool "Export kernel pagetable layout to userspace via debugfs" depends on DEBUG_KERNEL diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h index 0062a0125041..65c6e6e3a552 100644 --- a/arch/x86/include/asm/efi.h +++ b/arch/x86/include/asm/efi.h @@ -109,6 +109,8 @@ static inline bool efi_is_native(void) return IS_ENABLED(CONFIG_X86_64) == efi_enabled(EFI_64BIT); } +extern struct console early_efi_console; + #else /* * IF EFI is not configured, have the EFI calls return -ENOSYS. diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c index d15f575a861b..6d3d20073615 100644 --- a/arch/x86/kernel/early_printk.c +++ b/arch/x86/kernel/early_printk.c @@ -17,6 +17,8 @@ #include <asm/mrst.h> #include <asm/pgtable.h> #include <linux/usb/ehci_def.h> +#include <linux/efi.h> +#include <asm/efi.h> /* Simple VGA output */ #define VGABASE (__ISA_IO_base + 0xb8000) @@ -234,6 +236,11 @@ static int __init setup_early_printk(char *buf) early_console_register(&early_hsu_console, keep); } #endif +#ifdef CONFIG_EARLY_PRINTK_EFI + if (!strncmp(buf, "efi", 3)) + early_console_register(&early_efi_console, keep); +#endif + buf++; } return 0; diff --git a/arch/x86/platform/efi/Makefile b/arch/x86/platform/efi/Makefile index 6db1cc4c7534..b7b0b35c1981 100644 --- a/arch/x86/platform/efi/Makefile +++ b/arch/x86/platform/efi/Makefile @@ -1,2 +1,3 @@ obj-$(CONFIG_EFI) += efi.o efi_$(BITS).o efi_stub_$(BITS).o obj-$(CONFIG_ACPI_BGRT) += efi-bgrt.o +obj-$(CONFIG_EARLY_PRINTK_EFI) += early_printk.o diff --git a/arch/x86/platform/efi/early_printk.c b/arch/x86/platform/efi/early_printk.c new file mode 100644 index 000000000000..6599a0027b76 --- /dev/null +++ b/arch/x86/platform/efi/early_printk.c @@ -0,0 +1,191 @@ +/* + * 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 __init void early_efi_clear_scanline(unsigned int y) +{ + unsigned long base, *dst; + u16 len; + + base = boot_params.screen_info.lfb_base; + len = boot_params.screen_info.lfb_linelength; + + dst = early_ioremap(base + y*len, len); + if (!dst) + return; + + memset(dst, 0, len); + early_iounmap(dst, len); +} + +static __init void early_efi_scroll_up(void) +{ + unsigned long base, *dst, *src; + u16 len; + u32 i, height; + + base = boot_params.screen_info.lfb_base; + len = boot_params.screen_info.lfb_linelength; + height = boot_params.screen_info.lfb_height; + + for (i = 0; i < height - font->height; i++) { + dst = early_ioremap(base + i*len, len); + if (!dst) + return; + + src = early_ioremap(base + (i + font->height) * len, len); + if (!src) { + early_iounmap(dst, len); + return; + } + + memmove(dst, src, len); + + early_iounmap(src, len); + early_iounmap(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 __init void +early_efi_write(struct console *con, const char *str, unsigned int num) +{ + struct screen_info *si; + unsigned long base; + unsigned int len; + const char *s; + void *dst; + + base = boot_params.screen_info.lfb_base; + 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_ioremap(base + (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_iounmap(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 >= 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(); + + return 0; +} + +struct console early_efi_console = { + .name = "earlyefi", + .write = early_efi_write, + .setup = early_efi_setup, + .flags = CON_PRINTBUFFER, + .index = -1, +}; |