linux/drivers/tty/serial/kgdboc.c

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/*
* Based on the same principle as kgdboe using the NETPOLL api, this
* driver uses a console polling api to implement a gdb serial inteface
* which is multiplexed on a console port.
*
* Maintainer: Jason Wessel <jason.wessel@windriver.com>
*
* 2007-2008 (c) Jason Wessel - Wind River Systems, Inc.
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/kernel.h>
#include <linux/ctype.h>
#include <linux/kgdb.h>
#include <linux/kdb.h>
#include <linux/tty.h>
#include <linux/console.h>
#include <linux/vt_kern.h>
#include <linux/input.h>
#include <linux/module.h>
#define MAX_CONFIG_LEN 40
static struct kgdb_io kgdboc_io_ops;
/* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
static int configured = -1;
static char config[MAX_CONFIG_LEN];
static struct kparam_string kps = {
.string = config,
.maxlen = MAX_CONFIG_LEN,
};
static int kgdboc_use_kms; /* 1 if we use kernel mode switching */
static struct tty_driver *kgdb_tty_driver;
static int kgdb_tty_line;
#ifdef CONFIG_KDB_KEYBOARD
static int kgdboc_reset_connect(struct input_handler *handler,
struct input_dev *dev,
const struct input_device_id *id)
{
input_reset_device(dev);
/* Return an error - we do not want to bind, just to reset */
return -ENODEV;
}
static void kgdboc_reset_disconnect(struct input_handle *handle)
{
/* We do not expect anyone to actually bind to us */
BUG();
}
static const struct input_device_id kgdboc_reset_ids[] = {
{
.flags = INPUT_DEVICE_ID_MATCH_EVBIT,
.evbit = { BIT_MASK(EV_KEY) },
},
{ }
};
static struct input_handler kgdboc_reset_handler = {
.connect = kgdboc_reset_connect,
.disconnect = kgdboc_reset_disconnect,
.name = "kgdboc_reset",
.id_table = kgdboc_reset_ids,
};
static DEFINE_MUTEX(kgdboc_reset_mutex);
static void kgdboc_restore_input_helper(struct work_struct *dummy)
{
/*
* We need to take a mutex to prevent several instances of
* this work running on different CPUs so they don't try
* to register again already registered handler.
*/
mutex_lock(&kgdboc_reset_mutex);
if (input_register_handler(&kgdboc_reset_handler) == 0)
input_unregister_handler(&kgdboc_reset_handler);
mutex_unlock(&kgdboc_reset_mutex);
}
static DECLARE_WORK(kgdboc_restore_input_work, kgdboc_restore_input_helper);
static void kgdboc_restore_input(void)
{
if (likely(system_state == SYSTEM_RUNNING))
schedule_work(&kgdboc_restore_input_work);
}
static int kgdboc_register_kbd(char **cptr)
{
if (strncmp(*cptr, "kbd", 3) == 0 ||
strncmp(*cptr, "kdb", 3) == 0) {
if (kdb_poll_idx < KDB_POLL_FUNC_MAX) {
kdb_poll_funcs[kdb_poll_idx] = kdb_get_kbd_char;
kdb_poll_idx++;
if (cptr[0][3] == ',')
*cptr += 4;
else
return 1;
}
}
return 0;
}
static void kgdboc_unregister_kbd(void)
{
int i;
for (i = 0; i < kdb_poll_idx; i++) {
if (kdb_poll_funcs[i] == kdb_get_kbd_char) {
kdb_poll_idx--;
kdb_poll_funcs[i] = kdb_poll_funcs[kdb_poll_idx];
kdb_poll_funcs[kdb_poll_idx] = NULL;
i--;
}
}
workqueue: deprecate flush[_delayed]_work_sync() flush[_delayed]_work_sync() are now spurious. Mark them deprecated and convert all users to flush[_delayed]_work(). If you're cc'd and wondering what's going on: Now all workqueues are non-reentrant and the regular flushes guarantee that the work item is not pending or running on any CPU on return, so there's no reason to use the sync flushes at all and they're going away. This patch doesn't make any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Mattia Dongili <malattia@linux.it> Cc: Kent Yoder <key@linux.vnet.ibm.com> Cc: David Airlie <airlied@linux.ie> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Karsten Keil <isdn@linux-pingi.de> Cc: Bryan Wu <bryan.wu@canonical.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mauro Carvalho Chehab <mchehab@infradead.org> Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de> Cc: David Woodhouse <dwmw2@infradead.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: linux-wireless@vger.kernel.org Cc: Anton Vorontsov <cbou@mail.ru> Cc: Sangbeom Kim <sbkim73@samsung.com> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Petr Vandrovec <petr@vandrovec.name> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Avi Kivity <avi@redhat.com>
2012-08-20 21:51:24 +00:00
flush_work(&kgdboc_restore_input_work);
}
#else /* ! CONFIG_KDB_KEYBOARD */
#define kgdboc_register_kbd(x) 0
#define kgdboc_unregister_kbd()
#define kgdboc_restore_input()
#endif /* ! CONFIG_KDB_KEYBOARD */
static int kgdboc_option_setup(char *opt)
{
if (strlen(opt) >= MAX_CONFIG_LEN) {
printk(KERN_ERR "kgdboc: config string too long\n");
return -ENOSPC;
}
strcpy(config, opt);
return 0;
}
__setup("kgdboc=", kgdboc_option_setup);
static void cleanup_kgdboc(void)
{
tty/serial: Add kgdb_nmi driver This special driver makes it possible to temporary use NMI debugger port as a normal console by issuing 'nmi_console' command (assuming that the port is attached to KGDB). Unlike KDB's disable_nmi command, with this driver you are always able to go back to the debugger using KGDB escape sequence ($3#33). This is because this console driver processes the input in NMI context, and thus is able to intercept the magic sequence. Note that since the console interprets input and uses polling communication methods, for things like PPP it is still better to fully detach debugger port from the KGDB NMI (i.e. disable_nmi), and use raw console. Usually, to enter the debugger one have to type the magic sequence, so initially the kernel will print the following prompt on the NMI debugger console: Type $3#33 to enter the debugger> For convenience, there is a kgdb_fiq.knock kernel command line option, when set to 0, this turns the special command to just a return key press, so the kernel will be printing this: Hit <return> to enter the debugger> This is more convenient for long debugging sessions, although it makes nmi_console feature somewhat useless. And for the cases when NMI connected to a dedicated button, the knocking can be disabled altogether by setting kgdb_fiq.knock to -1. Suggested-by: Colin Cross <ccross@android.com> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Acked-by: Alan Cox <alan@linux.intel.com> Acked-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-24 21:27:56 +00:00
if (kgdb_unregister_nmi_console())
return;
kgdboc_unregister_kbd();
if (configured == 1)
kgdb_unregister_io_module(&kgdboc_io_ops);
}
static int configure_kgdboc(void)
{
struct tty_driver *p;
int tty_line = 0;
int err;
char *cptr = config;
struct console *cons;
err = kgdboc_option_setup(config);
if (err || !strlen(config) || isspace(config[0]))
goto noconfig;
err = -ENODEV;
kgdboc_io_ops.is_console = 0;
kgdb_tty_driver = NULL;
kgdboc_use_kms = 0;
if (strncmp(cptr, "kms,", 4) == 0) {
cptr += 4;
kgdboc_use_kms = 1;
}
if (kgdboc_register_kbd(&cptr))
goto do_register;
p = tty_find_polling_driver(cptr, &tty_line);
if (!p)
goto noconfig;
cons = console_drivers;
while (cons) {
int idx;
if (cons->device && cons->device(cons, &idx) == p &&
idx == tty_line) {
kgdboc_io_ops.is_console = 1;
break;
}
cons = cons->next;
}
kgdb_tty_driver = p;
kgdb_tty_line = tty_line;
do_register:
err = kgdb_register_io_module(&kgdboc_io_ops);
if (err)
goto noconfig;
tty/serial: Add kgdb_nmi driver This special driver makes it possible to temporary use NMI debugger port as a normal console by issuing 'nmi_console' command (assuming that the port is attached to KGDB). Unlike KDB's disable_nmi command, with this driver you are always able to go back to the debugger using KGDB escape sequence ($3#33). This is because this console driver processes the input in NMI context, and thus is able to intercept the magic sequence. Note that since the console interprets input and uses polling communication methods, for things like PPP it is still better to fully detach debugger port from the KGDB NMI (i.e. disable_nmi), and use raw console. Usually, to enter the debugger one have to type the magic sequence, so initially the kernel will print the following prompt on the NMI debugger console: Type $3#33 to enter the debugger> For convenience, there is a kgdb_fiq.knock kernel command line option, when set to 0, this turns the special command to just a return key press, so the kernel will be printing this: Hit <return> to enter the debugger> This is more convenient for long debugging sessions, although it makes nmi_console feature somewhat useless. And for the cases when NMI connected to a dedicated button, the knocking can be disabled altogether by setting kgdb_fiq.knock to -1. Suggested-by: Colin Cross <ccross@android.com> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Acked-by: Alan Cox <alan@linux.intel.com> Acked-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-24 21:27:56 +00:00
err = kgdb_register_nmi_console();
if (err)
goto nmi_con_failed;
configured = 1;
return 0;
tty/serial: Add kgdb_nmi driver This special driver makes it possible to temporary use NMI debugger port as a normal console by issuing 'nmi_console' command (assuming that the port is attached to KGDB). Unlike KDB's disable_nmi command, with this driver you are always able to go back to the debugger using KGDB escape sequence ($3#33). This is because this console driver processes the input in NMI context, and thus is able to intercept the magic sequence. Note that since the console interprets input and uses polling communication methods, for things like PPP it is still better to fully detach debugger port from the KGDB NMI (i.e. disable_nmi), and use raw console. Usually, to enter the debugger one have to type the magic sequence, so initially the kernel will print the following prompt on the NMI debugger console: Type $3#33 to enter the debugger> For convenience, there is a kgdb_fiq.knock kernel command line option, when set to 0, this turns the special command to just a return key press, so the kernel will be printing this: Hit <return> to enter the debugger> This is more convenient for long debugging sessions, although it makes nmi_console feature somewhat useless. And for the cases when NMI connected to a dedicated button, the knocking can be disabled altogether by setting kgdb_fiq.knock to -1. Suggested-by: Colin Cross <ccross@android.com> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Acked-by: Alan Cox <alan@linux.intel.com> Acked-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-24 21:27:56 +00:00
nmi_con_failed:
kgdb_unregister_io_module(&kgdboc_io_ops);
noconfig:
tty/serial: Add kgdb_nmi driver This special driver makes it possible to temporary use NMI debugger port as a normal console by issuing 'nmi_console' command (assuming that the port is attached to KGDB). Unlike KDB's disable_nmi command, with this driver you are always able to go back to the debugger using KGDB escape sequence ($3#33). This is because this console driver processes the input in NMI context, and thus is able to intercept the magic sequence. Note that since the console interprets input and uses polling communication methods, for things like PPP it is still better to fully detach debugger port from the KGDB NMI (i.e. disable_nmi), and use raw console. Usually, to enter the debugger one have to type the magic sequence, so initially the kernel will print the following prompt on the NMI debugger console: Type $3#33 to enter the debugger> For convenience, there is a kgdb_fiq.knock kernel command line option, when set to 0, this turns the special command to just a return key press, so the kernel will be printing this: Hit <return> to enter the debugger> This is more convenient for long debugging sessions, although it makes nmi_console feature somewhat useless. And for the cases when NMI connected to a dedicated button, the knocking can be disabled altogether by setting kgdb_fiq.knock to -1. Suggested-by: Colin Cross <ccross@android.com> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Acked-by: Alan Cox <alan@linux.intel.com> Acked-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-24 21:27:56 +00:00
kgdboc_unregister_kbd();
config[0] = 0;
configured = 0;
cleanup_kgdboc();
return err;
}
static int __init init_kgdboc(void)
{
/* Already configured? */
if (configured == 1)
return 0;
return configure_kgdboc();
}
static int kgdboc_get_char(void)
{
if (!kgdb_tty_driver)
return -1;
return kgdb_tty_driver->ops->poll_get_char(kgdb_tty_driver,
kgdb_tty_line);
}
static void kgdboc_put_char(u8 chr)
{
if (!kgdb_tty_driver)
return;
kgdb_tty_driver->ops->poll_put_char(kgdb_tty_driver,
kgdb_tty_line, chr);
}
static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp)
{
int len = strlen(kmessage);
if (len >= MAX_CONFIG_LEN) {
printk(KERN_ERR "kgdboc: config string too long\n");
return -ENOSPC;
}
/* Only copy in the string if the init function has not run yet */
if (configured < 0) {
strcpy(config, kmessage);
return 0;
}
if (kgdb_connected) {
printk(KERN_ERR
"kgdboc: Cannot reconfigure while KGDB is connected.\n");
return -EBUSY;
}
strcpy(config, kmessage);
/* Chop out \n char as a result of echo */
if (config[len - 1] == '\n')
config[len - 1] = '\0';
if (configured == 1)
cleanup_kgdboc();
/* Go and configure with the new params. */
return configure_kgdboc();
}
static int dbg_restore_graphics;
static void kgdboc_pre_exp_handler(void)
{
if (!dbg_restore_graphics && kgdboc_use_kms) {
dbg_restore_graphics = 1;
con_debug_enter(vc_cons[fg_console].d);
}
/* Increment the module count when the debugger is active */
if (!kgdb_connected)
try_module_get(THIS_MODULE);
}
static void kgdboc_post_exp_handler(void)
{
/* decrement the module count when the debugger detaches */
if (!kgdb_connected)
module_put(THIS_MODULE);
if (kgdboc_use_kms && dbg_restore_graphics) {
dbg_restore_graphics = 0;
con_debug_leave();
}
kgdboc_restore_input();
}
static struct kgdb_io kgdboc_io_ops = {
.name = "kgdboc",
.read_char = kgdboc_get_char,
.write_char = kgdboc_put_char,
.pre_exception = kgdboc_pre_exp_handler,
.post_exception = kgdboc_post_exp_handler,
};
#ifdef CONFIG_KGDB_SERIAL_CONSOLE
/* This is only available if kgdboc is a built in for early debugging */
static int __init kgdboc_early_init(char *opt)
{
/* save the first character of the config string because the
* init routine can destroy it.
*/
char save_ch;
kgdboc_option_setup(opt);
save_ch = config[0];
init_kgdboc();
config[0] = save_ch;
return 0;
}
early_param("ekgdboc", kgdboc_early_init);
#endif /* CONFIG_KGDB_SERIAL_CONSOLE */
module_init(init_kgdboc);
module_exit(cleanup_kgdboc);
module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);
MODULE_PARM_DESC(kgdboc, "<serial_device>[,baud]");
MODULE_DESCRIPTION("KGDB Console TTY Driver");
MODULE_LICENSE("GPL");