The patch titled
um: add earlyprintk support
has been added to the -mm tree. Its filename is
um-add-earlyprintk-support.patch
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------------------------------------------------------
Subject: um: add earlyprintk support
From: Richard Weinberger <richard@xxxxxx>
User Mode Linux can also benefit from earlyprintk. UML's earlyprintk
writes kernel messages directly to stdout.
Signed-off-by: Richard Weinberger <richard@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/um/Kconfig.debug | 10 +++++++++
arch/um/include/shared/os.h | 1
arch/um/kernel/Makefile | 1
arch/um/kernel/early_printk.c | 33 ++++++++++++++++++++++++++++++++
arch/um/os-Linux/util.c | 5 ++++
5 files changed, 50 insertions(+)
diff -puN arch/um/Kconfig.debug~um-add-earlyprintk-support arch/um/Kconfig.debug
--- a/arch/um/Kconfig.debug~um-add-earlyprintk-support
+++ a/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 -puN arch/um/include/shared/os.h~um-add-earlyprintk-support arch/um/include/shared/os.h
--- a/arch/um/include/shared/os.h~um-add-earlyprintk-support
+++ a/arch/um/include/shared/os.h
@@ -245,6 +245,7 @@ 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 -puN arch/um/kernel/Makefile~um-add-earlyprintk-support arch/um/kernel/Makefile
--- a/arch/um/kernel/Makefile~um-add-earlyprintk-support
+++ a/arch/um/kernel/Makefile
@@ -17,6 +17,7 @@ obj-y = config.o exec.o exitcode.o init_
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 -puN /dev/null arch/um/kernel/early_printk.c
--- /dev/null
+++ a/arch/um/kernel/early_printk.c
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2011 Richard Weinberger <richrd@xxxxxx>
+ *
+ * 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 -puN arch/um/os-Linux/util.c~um-add-earlyprintk-support arch/um/os-Linux/util.c
--- a/arch/um/os-Linux/util.c~um-add-earlyprintk-support
+++ a/arch/um/os-Linux/util.c
@@ -131,3 +131,8 @@ void os_dump_core(void)
remove_umid_dir();
uml_abort();
}
+
+void um_early_printk(const char *s, unsigned int n)
+{
+ printf("%.*s", n, s);
+}
_
Patches currently in -mm which might be from richard@xxxxxx are
origin.patch
mm-mmu_gather-rework.patch
powerpc-mmu_gather-rework.patch
sparc-mmu_gather-rework.patch
s390-mmu_gather-rework.patch
arm-mmu_gather-rework.patch
sh-mmu_gather-rework.patch
ia64-mmu_gather-rework.patch
um-mmu_gather-rework.patch
mm-now-that-all-old-mmu_gather-code-is-gone-remove-the-storage.patch
mm-powerpc-move-the-rcu-page-table-freeing-into-generic-code.patch
mm-extended-batches-for-generic-mmu_gather.patch
lockdep-mutex-provide-mutex_lock_nest_lock.patch
mm-remove-i_mmap_lock-lockbreak.patch
mm-convert-i_mmap_lock-to-a-mutex.patch
mm-revert-page_lock_anon_vma-lock-annotation.patch
mm-improve-page_lock_anon_vma-comment.patch
mm-use-refcounts-for-page_lock_anon_vma.patch
mm-convert-anon_vma-lock-to-a-mutex.patch
mm-optimize-page_lock_anon_vma-fast-path.patch
um-os_dump_core-cleanup.patch
um-fix-uml_lib_path.patch
um-remove-sighup-handler.patch
um-add-earlyprintk-support.patch
um-add-ucast-ethernet-transport.patch
um-print-info-about-fatal-segfaults.patch
um-include-linux-prefetchh.patch
um-fix-crash-while-os_dump_core.patch
remove-unused-proc_change_penalty-constant.patch
lib-consolidate-debug_stack_usage-option.patch
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