From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- drivers/tty/serial/kgdboc.c | 339 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 339 insertions(+) create mode 100644 drivers/tty/serial/kgdboc.c (limited to 'drivers/tty/serial/kgdboc.c') diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c new file mode 100644 index 000000000..a260cde74 --- /dev/null +++ b/drivers/tty/serial/kgdboc.c @@ -0,0 +1,339 @@ +/* + * 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 + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include + +#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--; + } + } + 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) +{ + 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; + + err = kgdb_register_nmi_console(); + if (err) + goto nmi_con_failed; + + configured = 1; + + return 0; + +nmi_con_failed: + kgdb_unregister_io_module(&kgdboc_io_ops); +noconfig: + 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, "[,baud]"); +MODULE_DESCRIPTION("KGDB Console TTY Driver"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3-54-g00ecf