Merge tag 'tty-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial driver updates from Greg KH:
 "Here is the big set of tty/serial driver changes for 5.12-rc1.

  Nothing huge, just lots of good cleanups and additions:

   - n_tty line discipline cleanups

   - vt core cleanups and reworks to make the code more "modern"

   - stm32 driver additions

   - tty led support added to the tty core and led layer

   - minor serial driver fixups and additions

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (54 commits)
  serial: core: Remove BUG_ON(in_interrupt()) check
  vt_ioctl: Remove in_interrupt() check
  dt-bindings: serial: imx: Switch to my personal address
  vt: keyboard, use new API for keyboard_tasklet
  serial: stm32: improve platform_get_irq condition handling in init_port
  serial: ifx6x60: Remove driver for deprecated platform
  tty: fix up iterate_tty_read() EOVERFLOW handling
  tty: fix up hung_up_tty_read() conversion
  tty: fix up hung_up_tty_write() conversion
  tty: teach the n_tty ICANON case about the new "cookie continuations" too
  tty: teach n_tty line discipline about the new "cookie continuations"
  tty: clean up legacy leftovers from n_tty line discipline
  tty: implement read_iter
  tty: convert tty_ldisc_ops 'read()' function to take a kernel pointer
  serial: remove sirf prima/atlas driver
  serial: mxs-auart: Remove <asm/cacheflush.h>
  serial: mxs-auart: Remove serial_mxs_probe_dt()
  serial: fsl_lpuart: Use of_device_get_match_data()
  dt-bindings: serial: renesas,hscif: Add r8a779a0 support
  tty: serial: Drop unused efm32 serial driver
  ...

1 files changed, 167 insertions, 43 deletions

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 082da38762fc..74733ec8f565 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -142,7 +142,7 @@ LIST_HEAD(tty_drivers);			/* linked list of tty drivers */
 /* Mutex to protect creating and releasing a tty */
 DEFINE_MUTEX(tty_mutex);
 
-static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
+static ssize_t tty_read(struct kiocb *, struct iov_iter *);
 static ssize_t tty_write(struct kiocb *, struct iov_iter *);
 static __poll_t tty_poll(struct file *, poll_table *);
 static int tty_open(struct inode *, struct file *);
@@ -429,8 +429,7 @@ struct tty_driver *tty_find_polling_driver(char *name, int *line)
 EXPORT_SYMBOL_GPL(tty_find_polling_driver);
 #endif
 
-static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
-				size_t count, loff_t *ppos)
+static ssize_t hung_up_tty_read(struct kiocb *iocb, struct iov_iter *to)
 {
 	return 0;
 }
@@ -473,8 +472,9 @@ static void tty_show_fdinfo(struct seq_file *m, struct file *file)
 
 static const struct file_operations tty_fops = {
 	.llseek		= no_llseek,
-	.read		= tty_read,
+	.read_iter	= tty_read,
 	.write_iter	= tty_write,
+	.splice_read	= generic_file_splice_read,
 	.splice_write	= iter_file_splice_write,
 	.poll		= tty_poll,
 	.unlocked_ioctl	= tty_ioctl,
@@ -487,8 +487,9 @@ static const struct file_operations tty_fops = {
 
 static const struct file_operations console_fops = {
 	.llseek		= no_llseek,
-	.read		= tty_read,
+	.read_iter	= tty_read,
 	.write_iter	= redirected_tty_write,
+	.splice_read	= generic_file_splice_read,
 	.splice_write	= iter_file_splice_write,
 	.poll		= tty_poll,
 	.unlocked_ioctl	= tty_ioctl,
@@ -500,7 +501,7 @@ static const struct file_operations console_fops = {
 
 static const struct file_operations hung_up_tty_fops = {
 	.llseek		= no_llseek,
-	.read		= hung_up_tty_read,
+	.read_iter	= hung_up_tty_read,
 	.write_iter	= hung_up_tty_write,
 	.poll		= hung_up_tty_poll,
 	.unlocked_ioctl	= hung_up_tty_ioctl,
@@ -539,6 +540,29 @@ void tty_wakeup(struct tty_struct *tty)
 EXPORT_SYMBOL_GPL(tty_wakeup);
 
 /**
+ *	tty_release_redirect	-	Release a redirect on a pty if present
+ *	@tty: tty device
+ *
+ *	This is available to the pty code so if the master closes, if the
+ *	slave is a redirect it can release the redirect.  It returns the
+ *	filp for the redirect, which must be fput when the operations on
+ *	the tty are completed.
+ */
+struct file *tty_release_redirect(struct tty_struct *tty)
+{
+	struct file *f = NULL;
+
+	spin_lock(&redirect_lock);
+	if (redirect && file_tty(redirect) == tty) {
+		f = redirect;
+		redirect = NULL;
+	}
+	spin_unlock(&redirect_lock);
+
+	return f;
+}
+
+/**
  *	__tty_hangup		-	actual handler for hangup events
  *	@tty: tty device
  *	@exit_session: if non-zero, signal all foreground group processes
@@ -564,7 +588,7 @@ EXPORT_SYMBOL_GPL(tty_wakeup);
 static void __tty_hangup(struct tty_struct *tty, int exit_session)
 {
 	struct file *cons_filp = NULL;
-	struct file *filp, *f = NULL;
+	struct file *filp, *f;
 	struct tty_file_private *priv;
 	int    closecount = 0, n;
 	int refs;
@@ -572,13 +596,7 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session)
 	if (!tty)
 		return;
 
-
-	spin_lock(&redirect_lock);
-	if (redirect && file_tty(redirect) == tty) {
-		f = redirect;
-		redirect = NULL;
-	}
-	spin_unlock(&redirect_lock);
+	f = tty_release_redirect(tty);
 
 	tty_lock(tty);
 
@@ -829,6 +847,72 @@ static void tty_update_time(struct timespec64 *time)
 		time->tv_sec = sec;
 }
 
+/*
+ * Iterate on the ldisc ->read() function until we've gotten all
+ * the data the ldisc has for us.
+ *
+ * The "cookie" is something that the ldisc read function can fill
+ * in to let us know that there is more data to be had.
+ *
+ * We promise to continue to call the ldisc until it stops returning
+ * data or clears the cookie. The cookie may be something that the
+ * ldisc maintains state for and needs to free.
+ */
+static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty,
+		struct file *file, struct iov_iter *to)
+{
+	int retval = 0;
+	void *cookie = NULL;
+	unsigned long offset = 0;
+	char kernel_buf[64];
+	size_t count = iov_iter_count(to);
+
+	do {
+		int size, copied;
+
+		size = count > sizeof(kernel_buf) ? sizeof(kernel_buf) : count;
+		size = ld->ops->read(tty, file, kernel_buf, size, &cookie, offset);
+		if (!size)
+			break;
+
+		if (size < 0) {
+			/* Did we have an earlier error (ie -EFAULT)? */
+			if (retval)
+				break;
+			retval = size;
+
+			/*
+			 * -EOVERFLOW means we didn't have enough space
+			 * for a whole packet, and we shouldn't return
+			 * a partial result.
+			 */
+			if (retval == -EOVERFLOW)
+				offset = 0;
+			break;
+		}
+
+		copied = copy_to_iter(kernel_buf, size, to);
+		offset += copied;
+		count -= copied;
+
+		/*
+		 * If the user copy failed, we still need to do another ->read()
+		 * call if we had a cookie to let the ldisc clear up.
+		 *
+		 * But make sure size is zeroed.
+		 */
+		if (unlikely(copied != size)) {
+			count = 0;
+			retval = -EFAULT;
+		}
+	} while (cookie);
+
+	/* We always clear tty buffer in case they contained passwords */
+	memzero_explicit(kernel_buf, sizeof(kernel_buf));
+	return offset ? offset : retval;
+}
+
+
 /**
  *	tty_read	-	read method for tty device files
  *	@file: pointer to tty file
@@ -844,10 +928,10 @@ static void tty_update_time(struct timespec64 *time)
  *	read calls may be outstanding in parallel.
  */
 
-static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
-			loff_t *ppos)
+static ssize_t tty_read(struct kiocb *iocb, struct iov_iter *to)
 {
 	int i;
+	struct file *file = iocb->ki_filp;
 	struct inode *inode = file_inode(file);
 	struct tty_struct *tty = file_tty(file);
 	struct tty_ldisc *ld;
@@ -861,11 +945,10 @@ static ssize_t tty_read(struct file *file, char __user *buf, size_t count,
 	   situation */
 	ld = tty_ldisc_ref_wait(tty);
 	if (!ld)
-		return hung_up_tty_read(file, buf, count, ppos);
+		return hung_up_tty_read(iocb, to);
+	i = -EIO;
 	if (ld->ops->read)
-		i = ld->ops->read(tty, file, buf, count);
-	else
-		i = -EIO;
+		i = iterate_tty_read(ld, tty, file, to);
 	tty_ldisc_deref(ld);
 
 	if (i > 0)
@@ -1889,22 +1972,7 @@ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp,
 	return driver;
 }
 
-/**
- *	tty_kopen	-	open a tty device for kernel
- *	@device: dev_t of device to open
- *
- *	Opens tty exclusively for kernel. Performs the driver lookup,
- *	makes sure it's not already opened and performs the first-time
- *	tty initialization.
- *
- *	Returns the locked initialized &tty_struct
- *
- *	Claims the global tty_mutex to serialize:
- *	  - concurrent first-time tty initialization
- *	  - concurrent tty driver removal w/ lookup
- *	  - concurrent tty removal from driver table
- */
-struct tty_struct *tty_kopen(dev_t device)
+static struct tty_struct *tty_kopen(dev_t device, int shared)
 {
 	struct tty_struct *tty;
 	struct tty_driver *driver;
@@ -1919,7 +1987,7 @@ struct tty_struct *tty_kopen(dev_t device)
 
 	/* check whether we're reopening an existing tty */
 	tty = tty_driver_lookup_tty(driver, NULL, index);
-	if (IS_ERR(tty))
+	if (IS_ERR(tty) || shared)
 		goto out;
 
 	if (tty) {
@@ -1937,7 +2005,42 @@ out:
 	tty_driver_kref_put(driver);
 	return tty;
 }
-EXPORT_SYMBOL_GPL(tty_kopen);
+
+/**
+ *	tty_kopen_exclusive	-	open a tty device for kernel
+ *	@device: dev_t of device to open
+ *
+ *	Opens tty exclusively for kernel. Performs the driver lookup,
+ *	makes sure it's not already opened and performs the first-time
+ *	tty initialization.
+ *
+ *	Returns the locked initialized &tty_struct
+ *
+ *	Claims the global tty_mutex to serialize:
+ *	  - concurrent first-time tty initialization
+ *	  - concurrent tty driver removal w/ lookup
+ *	  - concurrent tty removal from driver table
+ */
+struct tty_struct *tty_kopen_exclusive(dev_t device)
+{
+	return tty_kopen(device, 0);
+}
+EXPORT_SYMBOL_GPL(tty_kopen_exclusive);
+
+/**
+ *	tty_kopen_shared	-	open a tty device for shared in-kernel use
+ *	@device: dev_t of device to open
+ *
+ *	Opens an already existing tty for in-kernel use. Compared to
+ *	tty_kopen_exclusive() above it doesn't ensure to be the only user.
+ *
+ *	Locking is identical to tty_kopen() above.
+ */
+struct tty_struct *tty_kopen_shared(dev_t device)
+{
+	return tty_kopen(device, 1);
+}
+EXPORT_SYMBOL_GPL(tty_kopen_shared);
 
 /**
  *	tty_open_by_driver	-	open a tty device
@@ -2488,15 +2591,36 @@ static int tty_tiocmset(struct tty_struct *tty, unsigned int cmd,
 	return tty->ops->tiocmset(tty, set, clear);
 }
 
+/**
+ *	tty_get_icount		-	get tty statistics
+ *	@tty: tty device
+ *	@icount: output parameter
+ *
+ *	Gets a copy of the tty's icount statistics.
+ *
+ *	Locking: none (up to the driver)
+ */
+int tty_get_icount(struct tty_struct *tty,
+		   struct serial_icounter_struct *icount)
+{
+	memset(icount, 0, sizeof(*icount));
+
+	if (tty->ops->get_icount)
+		return tty->ops->get_icount(tty, icount);
+	else
+		return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(tty_get_icount);
+
 static int tty_tiocgicount(struct tty_struct *tty, void __user *arg)
 {
-	int retval = -EINVAL;
 	struct serial_icounter_struct icount;
-	memset(&icount, 0, sizeof(icount));
-	if (tty->ops->get_icount)
-		retval = tty->ops->get_icount(tty, &icount);
+	int retval;
+
+	retval = tty_get_icount(tty, &icount);
 	if (retval != 0)
 		return retval;
+
 	if (copy_to_user(arg, &icount, sizeof(icount)))
 		return -EFAULT;
 	return 0;
@@ -2887,7 +3011,7 @@ static long tty_compat_ioctl(struct file *file, unsigned int cmd,
 
 static int this_tty(const void *t, struct file *file, unsigned fd)
 {
-	if (likely(file->f_op->read != tty_read))
+	if (likely(file->f_op->read_iter != tty_read))
 		return 0;
 	return file_tty(file) != t ? 0 : fd + 1;
 }