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linux-next/arch/um/kernel/kmsg_dump.c
Thomas Meyer 04a418495e um: add a kmsg_dumper
Add a kmsg_dumper, that dumps the kmsg buffer to stdout, when no console
is available. This an enables the printing of early panic() calls
triggered in uml_postsetup().
When a panic() call happens so early in the UML kernel no
earlyprintk/console is available yet, but with a kmsg_dumper in place
the kernel message buffer will be outputted to the user, to give a
better hint, of what the failure was.

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
2015-04-13 21:17:37 +02:00

44 lines
839 B
C

#include <linux/kmsg_dump.h>
#include <linux/console.h>
#include <shared/init.h>
#include <shared/kern.h>
#include <os.h>
static void kmsg_dumper_stdout(struct kmsg_dumper *dumper,
enum kmsg_dump_reason reason)
{
static char line[1024];
size_t len = 0;
bool con_available = false;
/* only dump kmsg when no console is available */
if (!console_trylock())
return;
if (console_drivers != NULL)
con_available = true;
console_unlock();
if (con_available == true)
return;
printf("kmsg_dump:\n");
while (kmsg_dump_get_line(dumper, true, line, sizeof(line), &len)) {
line[len] = '\0';
printf("%s", line);
}
}
static struct kmsg_dumper kmsg_dumper = {
.dump = kmsg_dumper_stdout
};
int __init kmsg_dumper_stdout_init(void)
{
return kmsg_dump_register(&kmsg_dumper);
}
__uml_postsetup(kmsg_dumper_stdout_init);