blob: 6c3bc4b4da9834966f7fd19eb28454ac33988b9e [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-or-later
* kmsg dumper that ensures the OPAL console fully flushes panic messages
* Author: Russell Currey <>
* Copyright 2015 IBM Corporation.
#include <linux/kmsg_dump.h>
#include <asm/opal.h>
#include <asm/opal-api.h>
* Console output is controlled by OPAL firmware. The kernel regularly calls
* OPAL_POLL_EVENTS, which flushes some console output. In a panic state,
* however, the kernel no longer calls OPAL_POLL_EVENTS and the panic message
* may not be completely printed. This function does not actually dump the
* message, it just ensures that OPAL completely flushes the console buffer.
static void kmsg_dump_opal_console_flush(struct kmsg_dumper *dumper,
enum kmsg_dump_reason reason)
* Outside of a panic context the pollers will continue to run,
* so we don't need to do any special flushing.
if (reason != KMSG_DUMP_PANIC)
static struct kmsg_dumper opal_kmsg_dumper = {
.dump = kmsg_dump_opal_console_flush
void __init opal_kmsg_init(void)
int rc;
/* Add our dumper to the list */
rc = kmsg_dump_register(&opal_kmsg_dumper);
if (rc != 0)
pr_err("opal: kmsg_dump_register failed; returned %d\n", rc);