2 * kmsg dumper that ensures the OPAL console fully flushes panic messages
4 * Author: Russell Currey <ruscur@russell.cc>
6 * Copyright 2015 IBM Corporation.
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License as published by the
10 * Free Software Foundation; either version 2 of the License, or (at your
11 * option) any later version.
14 #include <linux/kmsg_dump.h>
17 #include <asm/opal-api.h>
20 * Console output is controlled by OPAL firmware. The kernel regularly calls
21 * OPAL_POLL_EVENTS, which flushes some console output. In a panic state,
22 * however, the kernel no longer calls OPAL_POLL_EVENTS and the panic message
23 * may not be completely printed. This function does not actually dump the
24 * message, it just ensures that OPAL completely flushes the console buffer.
26 static void kmsg_dump_opal_console_flush(struct kmsg_dumper *dumper,
27 enum kmsg_dump_reason reason)
30 * Outside of a panic context the pollers will continue to run,
31 * so we don't need to do any special flushing.
33 if (reason != KMSG_DUMP_PANIC)
36 opal_flush_console(0);
39 static struct kmsg_dumper opal_kmsg_dumper = {
40 .dump = kmsg_dump_opal_console_flush
43 void __init opal_kmsg_init(void)
47 /* Add our dumper to the list */
48 rc = kmsg_dump_register(&opal_kmsg_dumper);
50 pr_err("opal: kmsg_dump_register failed; returned %d\n", rc);