diff options
Diffstat (limited to 'drivers/tty/sysrq.c')
| -rw-r--r-- | drivers/tty/sysrq.c | 169 |
1 files changed, 124 insertions, 45 deletions
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c index eaa5d3efa79d..c556ed9db13d 100644 --- a/drivers/tty/sysrq.c +++ b/drivers/tty/sysrq.c @@ -554,7 +554,7 @@ EXPORT_SYMBOL(handle_sysrq); #ifdef CONFIG_INPUT /* Simple translation table for the SysRq keys */ -static const unsigned char sysrq_xlate[KEY_MAX + 1] = +static const unsigned char sysrq_xlate[KEY_CNT] = "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ @@ -563,53 +563,129 @@ static const unsigned char sysrq_xlate[KEY_MAX + 1] = "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ "\r\000/"; /* 0x60 - 0x6f */ -static bool sysrq_down; -static int sysrq_alt_use; -static int sysrq_alt; -static DEFINE_SPINLOCK(sysrq_event_lock); +struct sysrq_state { + struct input_handle handle; + struct work_struct reinject_work; + unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; + unsigned int alt; + unsigned int alt_use; + bool active; + bool need_reinject; +}; + +static void sysrq_reinject_alt_sysrq(struct work_struct *work) +{ + struct sysrq_state *sysrq = + container_of(work, struct sysrq_state, reinject_work); + struct input_handle *handle = &sysrq->handle; + unsigned int alt_code = sysrq->alt_use; + + if (sysrq->need_reinject) { + /* Simulate press and release of Alt + SysRq */ + input_inject_event(handle, EV_KEY, alt_code, 1); + input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); + input_inject_event(handle, EV_SYN, SYN_REPORT, 1); + + input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); + input_inject_event(handle, EV_KEY, alt_code, 0); + input_inject_event(handle, EV_SYN, SYN_REPORT, 1); + } +} -static bool sysrq_filter(struct input_handle *handle, unsigned int type, - unsigned int code, int value) +static bool sysrq_filter(struct input_handle *handle, + unsigned int type, unsigned int code, int value) { + struct sysrq_state *sysrq = handle->private; + bool was_active = sysrq->active; bool suppress; - /* We are called with interrupts disabled, just take the lock */ - spin_lock(&sysrq_event_lock); + switch (type) { - if (type != EV_KEY) - goto out; + case EV_SYN: + suppress = false; + break; - switch (code) { + case EV_KEY: + switch (code) { - case KEY_LEFTALT: - case KEY_RIGHTALT: - if (value) - sysrq_alt = code; - else { - if (sysrq_down && code == sysrq_alt_use) - sysrq_down = false; + case KEY_LEFTALT: + case KEY_RIGHTALT: + if (!value) { + /* One of ALTs is being released */ + if (sysrq->active && code == sysrq->alt_use) + sysrq->active = false; - sysrq_alt = 0; + sysrq->alt = KEY_RESERVED; + + } else if (value != 2) { + sysrq->alt = code; + sysrq->need_reinject = false; + } + break; + + case KEY_SYSRQ: + if (value == 1 && sysrq->alt != KEY_RESERVED) { + sysrq->active = true; + sysrq->alt_use = sysrq->alt; + /* + * If nothing else will be pressed we'll need + * to * re-inject Alt-SysRq keysroke. + */ + sysrq->need_reinject = true; + } + + /* + * Pretend that sysrq was never pressed at all. This + * is needed to properly handle KGDB which will try + * to release all keys after exiting debugger. If we + * do not clear key bit it KGDB will end up sending + * release events for Alt and SysRq, potentially + * triggering print screen function. + */ + if (sysrq->active) + clear_bit(KEY_SYSRQ, handle->dev->key); + + break; + + default: + if (sysrq->active && value && value != 2) { + sysrq->need_reinject = false; + __handle_sysrq(sysrq_xlate[code], true); + } + break; } - break; - case KEY_SYSRQ: - if (value == 1 && sysrq_alt) { - sysrq_down = true; - sysrq_alt_use = sysrq_alt; + suppress = sysrq->active; + + if (!sysrq->active) { + /* + * If we are not suppressing key presses keep track of + * keyboard state so we can release keys that have been + * pressed before entering SysRq mode. + */ + if (value) + set_bit(code, sysrq->key_down); + else + clear_bit(code, sysrq->key_down); + + if (was_active) + schedule_work(&sysrq->reinject_work); + + } else if (value == 0 && + test_and_clear_bit(code, sysrq->key_down)) { + /* + * Pass on release events for keys that was pressed before + * entering SysRq mode. + */ + suppress = false; } break; default: - if (sysrq_down && value && value != 2) - __handle_sysrq(sysrq_xlate[code], true); + suppress = sysrq->active; break; } -out: - suppress = sysrq_down; - spin_unlock(&sysrq_event_lock); - return suppress; } @@ -617,28 +693,28 @@ static int sysrq_connect(struct input_handler *handler, struct input_dev *dev, const struct input_device_id *id) { - struct input_handle *handle; + struct sysrq_state *sysrq; int error; - sysrq_down = false; - sysrq_alt = 0; - - handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL); - if (!handle) + sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); + if (!sysrq) return -ENOMEM; - handle->dev = dev; - handle->handler = handler; - handle->name = "sysrq"; + INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); + + sysrq->handle.dev = dev; + sysrq->handle.handler = handler; + sysrq->handle.name = "sysrq"; + sysrq->handle.private = sysrq; - error = input_register_handle(handle); + error = input_register_handle(&sysrq->handle); if (error) { pr_err("Failed to register input sysrq handler, error %d\n", error); goto err_free; } - error = input_open_device(handle); + error = input_open_device(&sysrq->handle); if (error) { pr_err("Failed to open input device, error %d\n", error); goto err_unregister; @@ -647,17 +723,20 @@ static int sysrq_connect(struct input_handler *handler, return 0; err_unregister: - input_unregister_handle(handle); + input_unregister_handle(&sysrq->handle); err_free: - kfree(handle); + kfree(sysrq); return error; } static void sysrq_disconnect(struct input_handle *handle) { + struct sysrq_state *sysrq = handle->private; + input_close_device(handle); + cancel_work_sync(&sysrq->reinject_work); input_unregister_handle(handle); - kfree(handle); + kfree(sysrq); } /* |