1 files changed, 111 insertions, 109 deletions

diff --git a/drivers/s390/char/sclp_vt220.c b/drivers/s390/char/sclp_vt220.c
index 4eed38cd0af6..62979adcb381 100644
--- a/drivers/s390/char/sclp_vt220.c
+++ b/drivers/s390/char/sclp_vt220.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * SCLP VT220 terminal driver.
  *
@@ -8,10 +9,12 @@
 
 #include <linux/module.h>
 #include <linux/spinlock.h>
+#include <linux/panic_notifier.h>
 #include <linux/list.h>
 #include <linux/wait.h>
 #include <linux/timer.h>
 #include <linux/kernel.h>
+#include <linux/sysrq.h>
 #include <linux/tty.h>
 #include <linux/tty_driver.h>
 #include <linux/tty_flip.h>
@@ -25,15 +28,16 @@
 #include <linux/reboot.h>
 #include <linux/slab.h>
 
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
 #include "sclp.h"
+#include "ctrlchar.h"
 
 #define SCLP_VT220_MAJOR		TTY_MAJOR
 #define SCLP_VT220_MINOR		65
 #define SCLP_VT220_DRIVER_NAME		"sclp_vt220"
 #define SCLP_VT220_DEVICE_NAME		"ttysclp"
-#define SCLP_VT220_CONSOLE_NAME		"ttyS"
-#define SCLP_VT220_CONSOLE_INDEX	1	/* console=ttyS1 */
+#define SCLP_VT220_CONSOLE_NAME		"ttysclp"
+#define SCLP_VT220_CONSOLE_INDEX	0	/* console=ttysclp0 */
 
 /* Representation of a single write request */
 struct sclp_vt220_request {
@@ -58,16 +62,13 @@ static struct tty_driver *sclp_vt220_driver;
 static struct tty_port sclp_vt220_port;
 
 /* Lock to protect internal data from concurrent access */
-static spinlock_t sclp_vt220_lock;
+static DEFINE_SPINLOCK(sclp_vt220_lock);
 
 /* List of empty pages to be used as write request buffers */
-static struct list_head sclp_vt220_empty;
+static LIST_HEAD(sclp_vt220_empty);
 
 /* List of pending requests */
-static struct list_head sclp_vt220_outqueue;
-
-/* Suspend mode flag */
-static int sclp_vt220_suspended;
+static LIST_HEAD(sclp_vt220_outqueue);
 
 /* Flag that output queue is currently running */
 static int sclp_vt220_queue_running;
@@ -92,18 +93,18 @@ static int __initdata sclp_vt220_init_count;
 static int sclp_vt220_flush_later;
 
 static void sclp_vt220_receiver_fn(struct evbuf_header *evbuf);
-static void sclp_vt220_pm_event_fn(struct sclp_register *reg,
-				   enum sclp_pm_event sclp_pm_event);
 static int __sclp_vt220_emit(struct sclp_vt220_request *request);
 static void sclp_vt220_emit_current(void);
 
-/* Registration structure for our interest in SCLP event buffers */
+/* Registration structure for SCLP output event buffers */
 static struct sclp_register sclp_vt220_register = {
 	.send_mask		= EVTYP_VT220MSG_MASK,
+};
+
+/* Registration structure for SCLP input event buffers */
+static struct sclp_register sclp_vt220_register_input = {
 	.receive_mask		= EVTYP_VT220MSG_MASK,
-	.state_change_fn	= NULL,
 	.receiver_fn		= sclp_vt220_receiver_fn,
-	.pm_event_fn		= sclp_vt220_pm_event_fn,
 };
 
 
@@ -129,7 +130,7 @@ sclp_vt220_process_queue(struct sclp_vt220_request *request)
 		if (!list_empty(&sclp_vt220_outqueue))
 			request = list_entry(sclp_vt220_outqueue.next,
 					     struct sclp_vt220_request, list);
-		if (!request || sclp_vt220_suspended) {
+		if (!request) {
 			sclp_vt220_queue_running = 0;
 			spin_unlock_irqrestore(&sclp_vt220_lock, flags);
 			break;
@@ -203,10 +204,6 @@ sclp_vt220_callback(struct sclp_req *request, void *data)
 static int
 __sclp_vt220_emit(struct sclp_vt220_request *request)
 {
-	if (!(sclp_vt220_register.sclp_receive_mask & EVTYP_VT220MSG_MASK)) {
-		request->sclp_req.status = SCLP_REQ_FAILED;
-		return -EIO;
-	}
 	request->sclp_req.command = SCLP_CMDW_WRITE_EVENT_DATA;
 	request->sclp_req.status = SCLP_REQ_FILLED;
 	request->sclp_req.callback = sclp_vt220_callback;
@@ -234,12 +231,11 @@ sclp_vt220_emit_current(void)
 			list_add_tail(&sclp_vt220_current_request->list,
 				      &sclp_vt220_outqueue);
 			sclp_vt220_current_request = NULL;
-			if (timer_pending(&sclp_vt220_timer))
-				del_timer(&sclp_vt220_timer);
+			timer_delete(&sclp_vt220_timer);
 		}
 		sclp_vt220_flush_later = 0;
 	}
-	if (sclp_vt220_queue_running || sclp_vt220_suspended)
+	if (sclp_vt220_queue_running)
 		goto out_unlock;
 	if (list_empty(&sclp_vt220_outqueue))
 		goto out_unlock;
@@ -323,7 +319,7 @@ sclp_vt220_add_msg(struct sclp_vt220_request *request,
 	buffer = (void *) ((addr_t) sccb + sccb->header.length);
 
 	if (convertlf) {
-		/* Perform Linefeed conversion (0x0a -> 0x0a 0x0d)*/
+		/* Perform Linefeed conversion (0x0a -> 0x0d 0x0a)*/
 		for (from=0, to=0;
 		     (from < count) && (to < sclp_vt220_space_left(request));
 		     from++) {
@@ -332,8 +328,8 @@ sclp_vt220_add_msg(struct sclp_vt220_request *request,
 			/* Perform conversion */
 			if (c == 0x0a) {
 				if (to + 1 < sclp_vt220_space_left(request)) {
-					((unsigned char *) buffer)[to++] = c;
 					((unsigned char *) buffer)[to++] = 0x0d;
+					((unsigned char *) buffer)[to++] = c;
 				} else
 					break;
 
@@ -355,7 +351,7 @@ sclp_vt220_add_msg(struct sclp_vt220_request *request,
  * Emit buffer after having waited long enough for more data to arrive.
  */
 static void
-sclp_vt220_timeout(unsigned long data)
+sclp_vt220_timeout(struct timer_list *unused)
 {
 	sclp_vt220_emit_current();
 }
@@ -418,7 +414,7 @@ __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
 			if (list_empty(&sclp_vt220_empty))
 				sclp_console_full++;
 			while (list_empty(&sclp_vt220_empty)) {
-				if (may_fail || sclp_vt220_suspended)
+				if (may_fail)
 					goto out;
 				if (sclp_vt220_drop_buffer())
 					break;
@@ -452,8 +448,6 @@ __sclp_vt220_write(const unsigned char *buf, int count, int do_schedule,
 	/* Setup timer to output current console buffer after some time */
 	if (sclp_vt220_current_request != NULL &&
 	    !timer_pending(&sclp_vt220_timer) && do_schedule) {
-		sclp_vt220_timer.function = sclp_vt220_timeout;
-		sclp_vt220_timer.data = 0UL;
 		sclp_vt220_timer.expires = jiffies + BUFFER_MAX_DELAY;
 		add_timer(&sclp_vt220_timer);
 	}
@@ -468,8 +462,8 @@ out:
  * user space or kernel space.  This routine will return the
  * number of characters actually accepted for writing.
  */
-static int
-sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count)
+static ssize_t
+sclp_vt220_write(struct tty_struct *tty, const u8 *buf, size_t count)
 {
 	return __sclp_vt220_write(buf, count, 1, 0, 1);
 }
@@ -478,6 +472,53 @@ sclp_vt220_write(struct tty_struct *tty, const unsigned char *buf, int count)
 #define	SCLP_VT220_SESSION_STARTED	0x80
 #define SCLP_VT220_SESSION_DATA		0x00
 
+#ifdef CONFIG_MAGIC_SYSRQ
+
+static int sysrq_pressed;
+static struct sysrq_work sysrq;
+
+static void sclp_vt220_reset_session(void)
+{
+	sysrq_pressed = 0;
+}
+
+static void sclp_vt220_handle_input(const char *buffer, unsigned int count)
+{
+	int i;
+
+	for (i = 0; i < count; i++) {
+		/* Handle magic sys request */
+		if (buffer[i] == ('O' ^ 0100)) { /* CTRL-O */
+			/*
+			 * If pressed again, reset sysrq_pressed
+			 * and flip CTRL-O character
+			 */
+			sysrq_pressed = !sysrq_pressed;
+			if (sysrq_pressed)
+				continue;
+		} else if (sysrq_pressed) {
+			sysrq.key = buffer[i];
+			schedule_sysrq_work(&sysrq);
+			sysrq_pressed = 0;
+			continue;
+		}
+		tty_insert_flip_char(&sclp_vt220_port, buffer[i], 0);
+	}
+}
+
+#else
+
+static void sclp_vt220_reset_session(void)
+{
+}
+
+static void sclp_vt220_handle_input(const char *buffer, unsigned int count)
+{
+	tty_insert_flip_string(&sclp_vt220_port, buffer, count);
+}
+
+#endif
+
 /*
  * Called by the SCLP to report incoming event buffers.
  */
@@ -493,12 +534,13 @@ sclp_vt220_receiver_fn(struct evbuf_header *evbuf)
 	switch (*buffer) {
 	case SCLP_VT220_SESSION_ENDED:
 	case SCLP_VT220_SESSION_STARTED:
+		sclp_vt220_reset_session();
 		break;
 	case SCLP_VT220_SESSION_DATA:
 		/* Send input to line discipline */
 		buffer++;
 		count--;
-		tty_insert_flip_string(&sclp_vt220_port, buffer, count);
+		sclp_vt220_handle_input(buffer, count);
 		tty_flip_buffer_push(&sclp_vt220_port);
 		break;
 	}
@@ -512,7 +554,6 @@ sclp_vt220_open(struct tty_struct *tty, struct file *filp)
 {
 	if (tty->count == 1) {
 		tty_port_tty_set(&sclp_vt220_port, tty);
-		sclp_vt220_port.low_latency = 0;
 		if (!tty->winsize.ws_row && !tty->winsize.ws_col) {
 			tty->winsize.ws_row = 24;
 			tty->winsize.ws_col = 80;
@@ -538,7 +579,7 @@ sclp_vt220_close(struct tty_struct *tty, struct file *filp)
  * done stuffing characters into the driver.
  */
 static int
-sclp_vt220_put_char(struct tty_struct *tty, unsigned char ch)
+sclp_vt220_put_char(struct tty_struct *tty, u8 ch)
 {
 	return __sclp_vt220_write(&ch, 1, 0, 0, 1);
 }
@@ -562,12 +603,12 @@ sclp_vt220_flush_chars(struct tty_struct *tty)
  * to change as output buffers get emptied, or if the output flow
  * control is acted.
  */
-static int
+static unsigned int
 sclp_vt220_write_room(struct tty_struct *tty)
 {
 	unsigned long flags;
 	struct list_head *l;
-	int count;
+	unsigned int count;
 
 	spin_lock_irqsave(&sclp_vt220_lock, flags);
 	count = 0;
@@ -582,16 +623,15 @@ sclp_vt220_write_room(struct tty_struct *tty)
 /*
  * Return number of buffered chars.
  */
-static int
+static unsigned int
 sclp_vt220_chars_in_buffer(struct tty_struct *tty)
 {
 	unsigned long flags;
 	struct list_head *l;
 	struct sclp_vt220_request *r;
-	int count;
+	unsigned int count = 0;
 
 	spin_lock_irqsave(&sclp_vt220_lock, flags);
-	count = 0;
 	if (sclp_vt220_current_request != NULL)
 		count = sclp_vt220_chars_stored(sclp_vt220_current_request);
 	list_for_each(l, &sclp_vt220_outqueue) {
@@ -646,10 +686,7 @@ static int __init __sclp_vt220_init(int num_pages)
 	sclp_vt220_init_count++;
 	if (sclp_vt220_init_count != 1)
 		return 0;
-	spin_lock_init(&sclp_vt220_lock);
-	INIT_LIST_HEAD(&sclp_vt220_empty);
-	INIT_LIST_HEAD(&sclp_vt220_outqueue);
-	init_timer(&sclp_vt220_timer);
+	timer_setup(&sclp_vt220_timer, sclp_vt220_timeout, 0);
 	tty_port_init(&sclp_vt220_port);
 	sclp_vt220_current_request = NULL;
 	sclp_vt220_buffered_chars = 0;
@@ -694,9 +731,9 @@ static int __init sclp_vt220_tty_init(void)
 
 	/* Note: we're not testing for CONSOLE_IS_SCLP here to preserve
 	 * symmetry between VM and LPAR systems regarding ttyS1. */
-	driver = alloc_tty_driver(1);
-	if (!driver)
-		return -ENOMEM;
+	driver = tty_alloc_driver(1, TTY_DRIVER_REAL_RAW);
+	if (IS_ERR(driver))
+		return PTR_ERR(driver);
 	rc = __sclp_vt220_init(MAX_KMEM_PAGES);
 	if (rc)
 		goto out_driver;
@@ -708,80 +745,28 @@ static int __init sclp_vt220_tty_init(void)
 	driver->type = TTY_DRIVER_TYPE_SYSTEM;
 	driver->subtype = SYSTEM_TYPE_TTY;
 	driver->init_termios = tty_std_termios;
-	driver->flags = TTY_DRIVER_REAL_RAW;
 	tty_set_operations(driver, &sclp_vt220_ops);
 	tty_port_link_device(&sclp_vt220_port, driver, 0);
 
 	rc = tty_register_driver(driver);
 	if (rc)
 		goto out_init;
+	rc = sclp_register(&sclp_vt220_register_input);
+	if (rc)
+		goto out_reg;
 	sclp_vt220_driver = driver;
 	return 0;
 
+out_reg:
+	tty_unregister_driver(driver);
 out_init:
 	__sclp_vt220_cleanup();
 out_driver:
-	put_tty_driver(driver);
+	tty_driver_kref_put(driver);
 	return rc;
 }
 __initcall(sclp_vt220_tty_init);
 
-static void __sclp_vt220_flush_buffer(void)
-{
-	unsigned long flags;
-
-	sclp_vt220_emit_current();
-	spin_lock_irqsave(&sclp_vt220_lock, flags);
-	if (timer_pending(&sclp_vt220_timer))
-		del_timer(&sclp_vt220_timer);
-	while (sclp_vt220_queue_running) {
-		spin_unlock_irqrestore(&sclp_vt220_lock, flags);
-		sclp_sync_wait();
-		spin_lock_irqsave(&sclp_vt220_lock, flags);
-	}
-	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
-}
-
-/*
- * Resume console: If there are cached messages, emit them.
- */
-static void sclp_vt220_resume(void)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&sclp_vt220_lock, flags);
-	sclp_vt220_suspended = 0;
-	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
-	sclp_vt220_emit_current();
-}
-
-/*
- * Suspend console: Set suspend flag and flush console
- */
-static void sclp_vt220_suspend(void)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&sclp_vt220_lock, flags);
-	sclp_vt220_suspended = 1;
-	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
-	__sclp_vt220_flush_buffer();
-}
-
-static void sclp_vt220_pm_event_fn(struct sclp_register *reg,
-				   enum sclp_pm_event sclp_pm_event)
-{
-	switch (sclp_pm_event) {
-	case SCLP_PM_EVENT_FREEZE:
-		sclp_vt220_suspend();
-		break;
-	case SCLP_PM_EVENT_RESTORE:
-	case SCLP_PM_EVENT_THAW:
-		sclp_vt220_resume();
-		break;
-	}
-}
-
 #ifdef CONFIG_SCLP_VT220_CONSOLE
 
 static void
@@ -797,22 +782,41 @@ sclp_vt220_con_device(struct console *c, int *index)
 	return sclp_vt220_driver;
 }
 
+/*
+ * This panic/reboot notifier runs in atomic context, so
+ * locking restrictions apply to prevent potential lockups.
+ */
 static int
 sclp_vt220_notify(struct notifier_block *self,
 			  unsigned long event, void *data)
 {
-	__sclp_vt220_flush_buffer();
-	return NOTIFY_OK;
+	unsigned long flags;
+
+	if (spin_is_locked(&sclp_vt220_lock))
+		return NOTIFY_DONE;
+
+	sclp_vt220_emit_current();
+
+	spin_lock_irqsave(&sclp_vt220_lock, flags);
+	timer_delete(&sclp_vt220_timer);
+	while (sclp_vt220_queue_running) {
+		spin_unlock_irqrestore(&sclp_vt220_lock, flags);
+		sclp_sync_wait();
+		spin_lock_irqsave(&sclp_vt220_lock, flags);
+	}
+	spin_unlock_irqrestore(&sclp_vt220_lock, flags);
+
+	return NOTIFY_DONE;
 }
 
 static struct notifier_block on_panic_nb = {
 	.notifier_call = sclp_vt220_notify,
-	.priority = 1,
+	.priority = INT_MIN + 1, /* run the callback late */
 };
 
 static struct notifier_block on_reboot_nb = {
 	.notifier_call = sclp_vt220_notify,
-	.priority = 1,
+	.priority = INT_MIN + 1, /* run the callback late */
 };
 
 /* Structure needed to register with printk */
@@ -830,8 +834,6 @@ sclp_vt220_con_init(void)
 {
 	int rc;
 
-	if (!CONSOLE_IS_SCLP)
-		return 0;
 	rc = __sclp_vt220_init(sclp_console_pages);
 	if (rc)
 		return rc;