1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kmsg_dump.h>
3 #include <linux/spinlock.h>
4 #include <linux/console.h>
5 #include <linux/string.h>
6 #include <shared/init.h>
7 #include <shared/kern.h>
8 #include <os.h>
9
10 static void kmsg_dumper_stdout(struct kmsg_dumper *dumper,
11 enum kmsg_dump_reason reason)
12 {
13 static struct kmsg_dump_iter iter;
14 static DEFINE_SPINLOCK(lock);
15 static char line[1024];
16 struct console *con;
17 unsigned long flags;
18 size_t len = 0;
19 int cookie;
20
21 /*
22 * If no consoles are available to output crash information, dump
23 * the kmsg buffer to stdout.
24 */
25
26 cookie = console_srcu_read_lock();
27 for_each_console_srcu(con) {
28 /*
29 * The ttynull console and disabled consoles are ignored
30 * since they cannot output. All other consoles are
31 * expected to output the crash information.
32 */
33 if (strcmp(con->name, "ttynull") != 0 &&
34 (console_srcu_read_flags(con) & CON_ENABLED)) {
35 break;
36 }
37 }
38 console_srcu_read_unlock(cookie);
39 if (con)
40 return;
41
42 if (!spin_trylock_irqsave(&lock, flags))
43 return;
44
45 kmsg_dump_rewind(&iter);
46
47 printf("kmsg_dump:\n");
48 while (kmsg_dump_get_line(&iter, true, line, sizeof(line), &len)) {
49 line[len] = '\0';
50 printf("%s", line);
51 }
52
53 spin_unlock_irqrestore(&lock, flags);
54 }
55
56 static struct kmsg_dumper kmsg_dumper = {
57 .dump = kmsg_dumper_stdout
58 };
59
60 static int __init kmsg_dumper_stdout_init(void)
61 {
62 return kmsg_dump_register(&kmsg_dumper);
63 }
64
65 __uml_postsetup(kmsg_dumper_stdout_init);
66
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