diff options
Diffstat (limited to 'arch/um')
| -rw-r--r-- | arch/um/Kconfig.debug | 10 | ||||
| -rw-r--r-- | arch/um/include/shared/os.h | 1 | ||||
| -rw-r--r-- | arch/um/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/um/kernel/early_printk.c | 33 | ||||
| -rw-r--r-- | arch/um/os-Linux/util.c | 5 |
5 files changed, 50 insertions, 0 deletions
diff --git a/arch/um/Kconfig.debug b/arch/um/Kconfig.debug index 8fce5e536b0f..85c86edd1e67 100644 --- a/arch/um/Kconfig.debug +++ b/arch/um/Kconfig.debug @@ -37,4 +37,14 @@ config DEBUG_STACK_USAGE stack seen so far. This option will slow down process creation and destruction somewhat. + +config EARLY_PRINTK + bool "Early printk" + default y + ---help--- + Write kernel log output directly to stdout. + + This is useful for kernel debugging when your machine crashes very + early before the console code is initialized. + endmenu diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h index f06a5da71a8f..83c7c2ecd614 100644 --- a/arch/um/include/shared/os.h +++ b/arch/um/include/shared/os.h @@ -244,6 +244,7 @@ extern int raw(int fd); extern void setup_machinename(char *machine_out); extern void setup_hostinfo(char *buf, int len); extern void os_dump_core(void) __attribute__ ((noreturn)); +extern void um_early_printk(const char *s, unsigned int n); /* time.c */ extern void idle_sleep(unsigned long long nsecs); diff --git a/arch/um/kernel/Makefile b/arch/um/kernel/Makefile index 1119233597a1..c4491c15afb2 100644 --- a/arch/um/kernel/Makefile +++ b/arch/um/kernel/Makefile @@ -17,6 +17,7 @@ obj-y = config.o exec.o exitcode.o init_task.o irq.o ksyms.o mem.o \ obj-$(CONFIG_BLK_DEV_INITRD) += initrd.o obj-$(CONFIG_GPROF) += gprof_syms.o obj-$(CONFIG_GCOV) += gmon_syms.o +obj-$(CONFIG_EARLY_PRINTK) += early_printk.o USER_OBJS := config.o diff --git a/arch/um/kernel/early_printk.c b/arch/um/kernel/early_printk.c new file mode 100644 index 000000000000..ec649bf72f68 --- /dev/null +++ b/arch/um/kernel/early_printk.c @@ -0,0 +1,33 @@ +/* + * Copyright (C) 2011 Richard Weinberger <richrd@nod.at> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/kernel.h> +#include <linux/console.h> +#include <linux/init.h> +#include "os.h" + +static void early_console_write(struct console *con, const char *s, unsigned int n) +{ + um_early_printk(s, n); +} + +static struct console early_console = { + .name = "earlycon", + .write = early_console_write, + .flags = CON_BOOT, + .index = -1, +}; + +static int __init setup_early_printk(char *buf) +{ + register_console(&early_console); + + return 0; +} + +early_param("earlyprintk", setup_early_printk); diff --git a/arch/um/os-Linux/util.c b/arch/um/os-Linux/util.c index 42827cafa6af..5803b1887672 100644 --- a/arch/um/os-Linux/util.c +++ b/arch/um/os-Linux/util.c @@ -139,3 +139,8 @@ void os_dump_core(void) uml_abort(); } + +void um_early_printk(const char *s, unsigned int n) +{ + printf("%.*s", n, s); +} |