1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun #include <linux/kernel.h>
3*4882a593Smuzhiyun #include <linux/init.h>
4*4882a593Smuzhiyun #include <linux/console.h>
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun #include "chan_user.h"
7*4882a593Smuzhiyun
8*4882a593Smuzhiyun /* ----------------------------------------------------------------------------- */
9*4882a593Smuzhiyun /* trivial console driver -- simply dump everything to stderr */
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun /*
12*4882a593Smuzhiyun * Don't register by default -- as this registers very early in the
13*4882a593Smuzhiyun * boot process it becomes the default console.
14*4882a593Smuzhiyun *
15*4882a593Smuzhiyun * Initialized at init time.
16*4882a593Smuzhiyun */
17*4882a593Smuzhiyun static int use_stderr_console = 0;
18*4882a593Smuzhiyun
stderr_console_write(struct console * console,const char * string,unsigned len)19*4882a593Smuzhiyun static void stderr_console_write(struct console *console, const char *string,
20*4882a593Smuzhiyun unsigned len)
21*4882a593Smuzhiyun {
22*4882a593Smuzhiyun generic_write(2 /* stderr */, string, len, NULL);
23*4882a593Smuzhiyun }
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun static struct console stderr_console = {
26*4882a593Smuzhiyun .name = "stderr",
27*4882a593Smuzhiyun .write = stderr_console_write,
28*4882a593Smuzhiyun .flags = CON_PRINTBUFFER,
29*4882a593Smuzhiyun };
30*4882a593Smuzhiyun
stderr_console_init(void)31*4882a593Smuzhiyun static int __init stderr_console_init(void)
32*4882a593Smuzhiyun {
33*4882a593Smuzhiyun if (use_stderr_console)
34*4882a593Smuzhiyun register_console(&stderr_console);
35*4882a593Smuzhiyun return 0;
36*4882a593Smuzhiyun }
37*4882a593Smuzhiyun console_initcall(stderr_console_init);
38*4882a593Smuzhiyun
stderr_setup(char * str)39*4882a593Smuzhiyun static int stderr_setup(char *str)
40*4882a593Smuzhiyun {
41*4882a593Smuzhiyun if (!str)
42*4882a593Smuzhiyun return 0;
43*4882a593Smuzhiyun use_stderr_console = simple_strtoul(str,&str,0);
44*4882a593Smuzhiyun return 1;
45*4882a593Smuzhiyun }
46*4882a593Smuzhiyun __setup("stderr=", stderr_setup);
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun /* The previous behavior of not unregistering led to /dev/console being
49*4882a593Smuzhiyun * impossible to open. My FC5 filesystem started having init die, and the
50*4882a593Smuzhiyun * system panicing because of this. Unregistering causes the real
51*4882a593Smuzhiyun * console to become the default console, and /dev/console can then be
52*4882a593Smuzhiyun * opened. Making this an initcall makes this happen late enough that
53*4882a593Smuzhiyun * there is no added value in dumping everything to stderr, and the
54*4882a593Smuzhiyun * normal console is good enough to show you all available output.
55*4882a593Smuzhiyun */
unregister_stderr(void)56*4882a593Smuzhiyun static int __init unregister_stderr(void)
57*4882a593Smuzhiyun {
58*4882a593Smuzhiyun unregister_console(&stderr_console);
59*4882a593Smuzhiyun
60*4882a593Smuzhiyun return 0;
61*4882a593Smuzhiyun }
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun __initcall(unregister_stderr);
64