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-rw-r--r--drivers/tty/sysrq.c169
1 files changed, 124 insertions, 45 deletions
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index eaa5d3efa79..c556ed9db13 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);
}
/*
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-26 05:40:10 +0000