4 files changed, 66 insertions, 61 deletions

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index 284749fb0f6b..a6d5164c33a9 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -69,13 +69,8 @@ static void pty_close(struct tty_struct *tty, struct file *filp)
 #ifdef CONFIG_UNIX98_PTYS
                 if (tty->driver == ptm_driver) {
                         mutex_lock(&devpts_mutex);
-                        if (tty->link->driver_data) {
-                                struct path *path = tty->link->driver_data;
-
-                                devpts_pty_kill(path->dentry);
-                                path_put(path);
-                                kfree(path);
-                        }
+                        if (tty->link->driver_data)
+                                devpts_pty_kill(tty->link->driver_data);
                         mutex_unlock(&devpts_mutex);
                 }
 #endif
@@ -607,25 +602,24 @@ static inline void legacy_pty_init(void) { }
 static struct cdev ptmx_cdev;
 
 /**
- *      pty_open_peer - open the peer of a pty
- *      @tty: the peer of the pty being opened
+ *      ptm_open_peer - open the peer of a pty
+ *      @master: the open struct file of the ptmx device node
+ *      @tty: the master of the pty being opened
+ *      @flags: the flags for open
  *
- *      Open the cached dentry in tty->link, providing a safe way for userspace
- *      to get the slave end of a pty (where they have the master fd and cannot
- *      access or trust the mount namespace /dev/pts was mounted inside).
+ *      Provide a race free way for userspace to open the slave end of a pty
+ *      (where they have the master fd and cannot access or trust the mount
+ *      namespace /dev/pts was mounted inside).
  */
-static struct file *pty_open_peer(struct tty_struct *tty, int flags)
-{
-        if (tty->driver->subtype != PTY_TYPE_MASTER)
-                return ERR_PTR(-EIO);
-        return dentry_open(tty->link->driver_data, flags, current_cred());
-}
-
-static int pty_get_peer(struct tty_struct *tty, int flags)
+int ptm_open_peer(struct file *master, struct tty_struct *tty, int flags)
 {
         int fd = -1;
-        struct file *filp = NULL;
+        struct file *filp;
         int retval = -EINVAL;
+        struct path path;
+
+        if (tty->driver != ptm_driver)
+                return -EIO;
 
         fd = get_unused_fd_flags(0);
         if (fd < 0) {
@@ -633,7 +627,16 @@ static int pty_get_peer(struct tty_struct *tty, int flags)
                 goto err;
         }
 
-        filp = pty_open_peer(tty, flags);
+        /* Compute the slave's path */
+        path.mnt = devpts_mntget(master, tty->driver_data);
+        if (IS_ERR(path.mnt)) {
+                retval = PTR_ERR(path.mnt);
+                goto err_put;
+        }
+        path.dentry = tty->link->driver_data;
+
+        filp = dentry_open(&path, flags, current_cred());
+        mntput(path.mnt);
         if (IS_ERR(filp)) {
                 retval = PTR_ERR(filp);
                 goto err_put;
@@ -662,8 +665,6 @@ static int pty_unix98_ioctl(struct tty_struct *tty,
                 return pty_get_pktmode(tty, (int __user *)arg);
         case TIOCGPTN: /* Get PT Number */
                 return put_user(tty->index, (unsigned int __user *)arg);
-        case TIOCGPTPEER: /* Open the other end */
-                return pty_get_peer(tty, (int) arg);
         case TIOCSIG:    /* Send signal to other side of pty */
                 return pty_signal(tty, (int) arg);
         }
@@ -791,7 +792,6 @@ static int ptmx_open(struct inode *inode, struct file *filp)
 {
         struct pts_fs_info *fsi;
         struct tty_struct *tty;
-        struct path *pts_path;
         struct dentry *dentry;
         int retval;
         int index;
@@ -845,26 +845,16 @@ static int ptmx_open(struct inode *inode, struct file *filp)
                 retval = PTR_ERR(dentry);
                 goto err_release;
         }
-        /* We need to cache a fake path for TIOCGPTPEER. */
-        pts_path = kmalloc(sizeof(struct path), GFP_KERNEL);
-        if (!pts_path)
-                goto err_release;
-        pts_path->mnt = filp->f_path.mnt;
-        pts_path->dentry = dentry;
-        path_get(pts_path);
-        tty->link->driver_data = pts_path;
+        tty->link->driver_data = dentry;
 
         retval = ptm_driver->ops->open(tty, filp);
         if (retval)
-                goto err_path_put;
+                goto err_release;
 
         tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
 
         tty_unlock(tty);
         return 0;
-err_path_put:
-        path_put(pts_path);
-        kfree(pts_path);
 err_release:
         tty_unlock(tty);
         // This will also put-ref the fsi
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index b5def356af63..1aab3010fbfa 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -1043,13 +1043,24 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
                 if (up->dl_write)
                         uart->dl_write = up->dl_write;
 
-                if (serial8250_isa_config != NULL)
-                        serial8250_isa_config(0, &uart->port,
-                                        &uart->capabilities);
+                if (uart->port.type != PORT_8250_CIR) {
+                        if (serial8250_isa_config != NULL)
+                                serial8250_isa_config(0, &uart->port,
+                                                &uart->capabilities);
+
+                        ret = uart_add_one_port(&serial8250_reg,
+                                                &uart->port);
+                        if (ret == 0)
+                                ret = uart->port.line;
+                } else {
+                        dev_info(uart->port.dev,
+                                "skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
+                                uart->port.iobase,
+                                (unsigned long long)uart->port.mapbase,
+                                uart->port.irq);
 
-                ret = uart_add_one_port(&serial8250_reg, &uart->port);
-                if (ret == 0)
-                        ret = uart->port.line;
+                        ret = 0;
+                }
         }
         mutex_unlock(&serial_mutex);
 
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 8a857bb34fbb..1888d168a41c 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -142,15 +142,7 @@ static struct vendor_data vendor_sbsa = {
         .fixed_options          = true,
 };
 
-/*
- * Erratum 44 for QDF2432v1 and QDF2400v1 SoCs describes the BUSY bit as
- * occasionally getting stuck as 1. To avoid the potential for a hang, check
- * TXFE == 0 instead of BUSY == 1. This may not be suitable for all UART
- * implementations, so only do so if an affected platform is detected in
- * parse_spcr().
- */
-static bool qdf2400_e44_present = false;
-
+#ifdef CONFIG_ACPI_SPCR_TABLE
 static struct vendor_data vendor_qdt_qdf2400_e44 = {
         .reg_offset             = pl011_std_offsets,
         .fr_busy                = UART011_FR_TXFE,
@@ -165,6 +157,7 @@ static struct vendor_data vendor_qdt_qdf2400_e44 = {
         .always_enabled         = true,
         .fixed_options          = true,
 };
+#endif
 
 static u16 pl011_st_offsets[REG_ARRAY_SIZE] = {
         [REG_DR] = UART01x_DR,
@@ -2375,12 +2368,14 @@ static int __init pl011_console_match(struct console *co, char *name, int idx,
         resource_size_t addr;
         int i;
 
-        if (strcmp(name, "qdf2400_e44") == 0) {
-                pr_info_once("UART: Working around QDF2400 SoC erratum 44");
-                qdf2400_e44_present = true;
-        } else if (strcmp(name, "pl011") != 0) {
+        /*
+         * Systems affected by the Qualcomm Technologies QDF2400 E44 erratum
+         * have a distinct console name, so make sure we check for that.
+         * The actual implementation of the erratum occurs in the probe
+         * function.
+         */
+        if ((strcmp(name, "qdf2400_e44") != 0) && (strcmp(name, "pl011") != 0))
                 return -ENODEV;
-        }
 
         if (uart_parse_earlycon(options, &iotype, &addr, &options))
                 return -ENODEV;
@@ -2734,11 +2729,17 @@ static int sbsa_uart_probe(struct platform_device *pdev)
         }
         uap->port.irq   = ret;
 
-        uap->reg_offset = vendor_sbsa.reg_offset;
-        uap->vendor     = qdf2400_e44_present ?
-                                        &vendor_qdt_qdf2400_e44 : &vendor_sbsa;
+#ifdef CONFIG_ACPI_SPCR_TABLE
+        if (qdf2400_e44_present) {
+                dev_info(&pdev->dev, "working around QDF2400 SoC erratum 44\n");
+                uap->vendor = &vendor_qdt_qdf2400_e44;
+        } else
+#endif
+                uap->vendor = &vendor_sbsa;
+
+        uap->reg_offset = uap->vendor->reg_offset;
         uap->fifosize   = 32;
-        uap->port.iotype = vendor_sbsa.access_32b ? UPIO_MEM32 : UPIO_MEM;
+        uap->port.iotype = uap->vendor->access_32b ? UPIO_MEM32 : UPIO_MEM;
         uap->port.ops   = &sbsa_uart_pops;
         uap->fixed_baud = baudrate;
 
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 974b13d24401..10c4038c0e8d 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2518,6 +2518,9 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
         case TIOCSSERIAL:
                 tty_warn_deprecated_flags(p);
                 break;
+        case TIOCGPTPEER:
+                /* Special because the struct file is needed */
+                return ptm_open_peer(file, tty, (int)arg);
         default:
                 retval = tty_jobctrl_ioctl(tty, real_tty, file, cmd, arg);
                 if (retval != -ENOIOCTLCMD)