serial/arc-uart: Don't index with -ve platform_device->id

probe routine could index into port[] with -ve index. The check in
arc_uart_init_one() was too late.

This came to light when trying to port driver to CONFIG_OF, where
bydefault of-core code sets -ve platform dev id and in absence of
DT serial aliases, driver would use the -ve index.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/arc_uart.c b/drivers/tty/serial/arc_uart.c
index 3e0b3fa..8089dc3 100644 (file)
--- a/drivers/tty/serial/arc_uart.c
+++ b/drivers/tty/serial/arc_uart.c
@@ -526,15 +526,11 @@ static struct uart_ops arc_serial_pops = {
 };
 
 static int
-arc_uart_init_one(struct platform_device *pdev, struct arc_uart_port *uart)
+arc_uart_init_one(struct platform_device *pdev, int dev_id)
 {
        struct resource *res, *res2;
        unsigned long *plat_data;
-
-       if (pdev->id < 0 || pdev->id >= CONFIG_SERIAL_ARC_NR_PORTS) {
-               dev_err(&pdev->dev, "Wrong uart platform device id.\n");
-               return -ENOENT;
-       }
+       struct arc_uart_port *uart = &arc_uart_ports[dev_id];
 
        plat_data = ((unsigned long *)(pdev->dev.platform_data));
        uart->baud = plat_data[0];
@@ -557,7 +553,7 @@ arc_uart_init_one(struct platform_device *pdev, struct arc_uart_port *uart)
        uart->port.dev = &pdev->dev;
        uart->port.iotype = UPIO_MEM;
        uart->port.flags = UPF_BOOT_AUTOCONF;
-       uart->port.line = pdev->id;
+       uart->port.line = dev_id;
        uart->port.ops = &arc_serial_pops;
 
        uart->port.uartclk = plat_data[1];
@@ -657,9 +653,14 @@ static struct __initdata console arc_early_serial_console = {
 
 static int arc_serial_probe_earlyprintk(struct platform_device *pdev)
 {
-       arc_early_serial_console.index = pdev->id;
+       int dev_id = pdev->id < 0 ? 0 : pdev->id;
+       int rc;
 
-       arc_uart_init_one(pdev, &arc_uart_ports[pdev->id]);
+       arc_early_serial_console.index = dev_id;
+
+       rc = arc_uart_init_one(pdev, dev_id);
+       if (rc)
+               panic("early console init failed\n");
 
        arc_serial_console_setup(&arc_early_serial_console, NULL);
 
@@ -675,18 +676,18 @@ static int arc_serial_probe_earlyprintk(struct platform_device *pdev)
 
 static int arc_serial_probe(struct platform_device *pdev)
 {
-       struct arc_uart_port *uart;
-       int rc;
+       int rc, dev_id;
 
        if (is_early_platform_device(pdev))
                return arc_serial_probe_earlyprintk(pdev);
 
-       uart = &arc_uart_ports[pdev->id];
-       rc = arc_uart_init_one(pdev, uart);
+       dev_id = pdev->id < 0 ? 0 : pdev->id;
+       rc = arc_uart_init_one(pdev, dev_id);
        if (rc)
                return rc;
 
-       return uart_add_one_port(&arc_uart_driver, &uart->port);
+       rc = uart_add_one_port(&arc_uart_driver, &arc_uart_ports[dev_id].port);
+       return rc;
 }
 
 static int arc_serial_remove(struct platform_device *pdev)