5.4.36-rc1 review

@@ -183,7 +183,6 @@ MODULE_PARM_DESC(rx_timeout, "Rx timeout
  * @pclk:		APB clock
  * @cdns_uart_driver:	Pointer to UART driver
  * @baud:		Current baud rate
- * @id:			Port ID
  * @clk_rate_change_nb:	Notifier block for clock changes
  * @quirks:		Flags for RXBS support.
  */

@@ -193,7 +192,6 @@ struct cdns_uart {
 	struct clk		*pclk;
 	struct uart_driver	*cdns_uart_driver;
 	unsigned int		baud;
-	int			id;
 	struct notifier_block	clk_rate_change_nb;
 	u32			quirks;
 	bool cts_override;

@@ -1398,7 +1396,7 @@ MODULE_DEVICE_TABLE(of, cdns_uart_of_mat
  */
 static int cdns_uart_probe(struct platform_device *pdev)
 {
-	int rc, irq;
+	int rc, id, irq;
 	struct uart_port *port;
 	struct resource *res;
 	struct cdns_uart *cdns_uart_data;

@@ -1424,18 +1422,18 @@ static int cdns_uart_probe(struct platfo
 		return -ENOMEM;
 
 	/* Look for a serialN alias */
-	cdns_uart_data->id = of_alias_get_id(pdev->dev.of_node, "serial");
-	if (cdns_uart_data->id < 0)
-		cdns_uart_data->id = 0;
+	id = of_alias_get_id(pdev->dev.of_node, "serial");
+	if (id < 0)
+		id = 0;
 
-	if (cdns_uart_data->id >= CDNS_UART_NR_PORTS) {
+	if (id >= CDNS_UART_NR_PORTS) {
 		dev_err(&pdev->dev, "Cannot get uart_port structure\n");
 		return -ENODEV;
 	}
 
 	/* There is a need to use unique driver name */
 	driver_name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s%d",
-				     CDNS_UART_NAME, cdns_uart_data->id);
+				     CDNS_UART_NAME, id);
 	if (!driver_name)
 		return -ENOMEM;
 

@@ -1443,7 +1441,7 @@ static int cdns_uart_probe(struct platfo
 	cdns_uart_uart_driver->driver_name = driver_name;
 	cdns_uart_uart_driver->dev_name	= CDNS_UART_TTY_NAME;
 	cdns_uart_uart_driver->major = CDNS_UART_MAJOR;
-	cdns_uart_uart_driver->minor = cdns_uart_data->id;
+	cdns_uart_uart_driver->minor = id;
 	cdns_uart_uart_driver->nr = 1;
 
 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE

@@ -1454,7 +1452,7 @@ static int cdns_uart_probe(struct platfo
 
 	strncpy(cdns_uart_console->name, CDNS_UART_TTY_NAME,
 		sizeof(cdns_uart_console->name));
-	cdns_uart_console->index = cdns_uart_data->id;
+	cdns_uart_console->index = id;
 	cdns_uart_console->write = cdns_uart_console_write;
 	cdns_uart_console->device = uart_console_device;
 	cdns_uart_console->setup = cdns_uart_console_setup;

@@ -1476,7 +1474,7 @@ static int cdns_uart_probe(struct platfo
 	 * registration because tty_driver structure is not filled.
 	 * name_base is 0 by default.
 	 */
-	cdns_uart_uart_driver->tty_driver->name_base = cdns_uart_data->id;
+	cdns_uart_uart_driver->tty_driver->name_base = id;
 
 	match = of_match_node(cdns_uart_of_match, pdev->dev.of_node);
 	if (match && match->data) {

@@ -31,6 +31,7 @@
 #define CDNS_UART_TTY_NAME	"ttyPS"
 #define CDNS_UART_NAME		"xuartps"
 #define CDNS_UART_MAJOR		0	/* use dynamic node allocation */
+#define CDNS_UART_MINOR		0	/* works best with devtmpfs */
 #define CDNS_UART_NR_PORTS	16
 #define CDNS_UART_FIFO_SIZE	64	/* FIFO size */
 #define CDNS_UART_REGISTER_SPACE	0x1000

@@ -1118,6 +1119,8 @@ static const struct uart_ops cdns_uart_o
 #endif
 };
 
+static struct uart_driver cdns_uart_uart_driver;
+
 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
 /**
  * cdns_uart_console_putchar - write the character to the FIFO buffer

@@ -1257,6 +1260,16 @@ static int cdns_uart_console_setup(struc
 
 	return uart_set_options(port, co, baud, parity, bits, flow);
 }
+
+static struct console cdns_uart_console = {
+	.name	= CDNS_UART_TTY_NAME,
+	.write	= cdns_uart_console_write,
+	.device	= uart_console_device,
+	.setup	= cdns_uart_console_setup,
+	.flags	= CON_PRINTBUFFER,
+	.index	= -1, /* Specified on the cmdline (e.g. console=ttyPS ) */
+	.data	= &cdns_uart_uart_driver,
+};
 #endif /* CONFIG_SERIAL_XILINX_PS_UART_CONSOLE */
 
 #ifdef CONFIG_PM_SLEEP

@@ -1388,6 +1401,9 @@ static const struct of_device_id cdns_ua
 };
 MODULE_DEVICE_TABLE(of, cdns_uart_of_match);
 
+/* Temporary variable for storing number of instances */
+static int instances;
+
 /**
  * cdns_uart_probe - Platform driver probe
  * @pdev: Pointer to the platform device structure

@@ -1401,11 +1417,6 @@ static int cdns_uart_probe(struct platfo
 	struct resource *res;
 	struct cdns_uart *cdns_uart_data;
 	const struct of_device_id *match;
-	struct uart_driver *cdns_uart_uart_driver;
-	char *driver_name;
-#ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
-	struct console *cdns_uart_console;
-#endif
 
 	cdns_uart_data = devm_kzalloc(&pdev->dev, sizeof(*cdns_uart_data),
 			GFP_KERNEL);

@@ -1415,12 +1426,6 @@ static int cdns_uart_probe(struct platfo
 	if (!port)
 		return -ENOMEM;
 
-	cdns_uart_uart_driver = devm_kzalloc(&pdev->dev,
-					     sizeof(*cdns_uart_uart_driver),
-					     GFP_KERNEL);
-	if (!cdns_uart_uart_driver)
-		return -ENOMEM;
-
 	/* Look for a serialN alias */
 	id = of_alias_get_id(pdev->dev.of_node, "serial");
 	if (id < 0)

@@ -1431,50 +1436,25 @@ static int cdns_uart_probe(struct platfo
 		return -ENODEV;
 	}
 
-	/* There is a need to use unique driver name */
-	driver_name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s%d",
-				     CDNS_UART_NAME, id);
-	if (!driver_name)
-		return -ENOMEM;
-
-	cdns_uart_uart_driver->owner = THIS_MODULE;
-	cdns_uart_uart_driver->driver_name = driver_name;
-	cdns_uart_uart_driver->dev_name	= CDNS_UART_TTY_NAME;
-	cdns_uart_uart_driver->major = CDNS_UART_MAJOR;
-	cdns_uart_uart_driver->minor = id;
-	cdns_uart_uart_driver->nr = 1;
-
+	if (!cdns_uart_uart_driver.state) {
+		cdns_uart_uart_driver.owner = THIS_MODULE;
+		cdns_uart_uart_driver.driver_name = CDNS_UART_NAME;
+		cdns_uart_uart_driver.dev_name = CDNS_UART_TTY_NAME;
+		cdns_uart_uart_driver.major = CDNS_UART_MAJOR;
+		cdns_uart_uart_driver.minor = CDNS_UART_MINOR;
+		cdns_uart_uart_driver.nr = CDNS_UART_NR_PORTS;
 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
-	cdns_uart_console = devm_kzalloc(&pdev->dev, sizeof(*cdns_uart_console),
-					 GFP_KERNEL);
-	if (!cdns_uart_console)
-		return -ENOMEM;
-
-	strncpy(cdns_uart_console->name, CDNS_UART_TTY_NAME,
-		sizeof(cdns_uart_console->name));
-	cdns_uart_console->index = id;
-	cdns_uart_console->write = cdns_uart_console_write;
-	cdns_uart_console->device = uart_console_device;
-	cdns_uart_console->setup = cdns_uart_console_setup;
-	cdns_uart_console->flags = CON_PRINTBUFFER;
-	cdns_uart_console->data = cdns_uart_uart_driver;
-	cdns_uart_uart_driver->cons = cdns_uart_console;
+		cdns_uart_uart_driver.cons = &cdns_uart_console;
 #endif
 
-	rc = uart_register_driver(cdns_uart_uart_driver);
-	if (rc < 0) {
-		dev_err(&pdev->dev, "Failed to register driver\n");
-		return rc;
+		rc = uart_register_driver(&cdns_uart_uart_driver);
+		if (rc < 0) {
+			dev_err(&pdev->dev, "Failed to register driver\n");
+			return rc;
+		}
 	}
 
-	cdns_uart_data->cdns_uart_driver = cdns_uart_uart_driver;
-
-	/*
-	 * Setting up proper name_base needs to be done after uart
-	 * registration because tty_driver structure is not filled.
-	 * name_base is 0 by default.
-	 */
-	cdns_uart_uart_driver->tty_driver->name_base = id;
+	cdns_uart_data->cdns_uart_driver = &cdns_uart_uart_driver;
 
 	match = of_match_node(cdns_uart_of_match, pdev->dev.of_node);
 	if (match && match->data) {

@@ -1551,6 +1531,7 @@ static int cdns_uart_probe(struct platfo
 	port->flags	= UPF_BOOT_AUTOCONF;
 	port->ops	= &cdns_uart_ops;
 	port->fifosize	= CDNS_UART_FIFO_SIZE;
+	port->line	= id;
 
 	/*
 	 * Register the port.

@@ -1582,7 +1563,7 @@ static int cdns_uart_probe(struct platfo
 		console_port = port;
 #endif
 
-	rc = uart_add_one_port(cdns_uart_uart_driver, port);
+	rc = uart_add_one_port(&cdns_uart_uart_driver, port);
 	if (rc) {
 		dev_err(&pdev->dev,
 			"uart_add_one_port() failed; err=%i\n", rc);

@@ -1592,12 +1573,15 @@ static int cdns_uart_probe(struct platfo
 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
 	/* This is not port which is used for console that's why clean it up */
 	if (console_port == port &&
-	    !(cdns_uart_uart_driver->cons->flags & CON_ENABLED))
+	    !(cdns_uart_uart_driver.cons->flags & CON_ENABLED))
 		console_port = NULL;
 #endif
 
 	cdns_uart_data->cts_override = of_property_read_bool(pdev->dev.of_node,
 							     "cts-override");
+
+	instances++;
+
 	return 0;
 
 err_out_pm_disable:

@@ -1613,8 +1597,8 @@ err_out_clk_disable:
 err_out_clk_dis_pclk:
 	clk_disable_unprepare(cdns_uart_data->pclk);
 err_out_unregister_driver:
-	uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
-
+	if (!instances)
+		uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
 	return rc;
 }
 

@@ -1649,7 +1633,8 @@ static int cdns_uart_remove(struct platf
 		console_port = NULL;
 #endif
 
-	uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
+	if (!--instances)
+		uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
 	return rc;
 }
 

@@ -4,6 +4,9 @@
  */
 #ifndef __ASM_COMPAT_H
 #define __ASM_COMPAT_H
+
+#include <asm-generic/compat.h>
+
 #ifdef CONFIG_COMPAT
 
 /*

@@ -13,8 +16,6 @@
 #include <linux/sched.h>
 #include <linux/sched/task_stack.h>
 
-#include <asm-generic/compat.h>
-
 #define COMPAT_USER_HZ		100
 #ifdef __AARCH64EB__
 #define COMPAT_UTS_MACHINE	"armv8b\0\0"

@@ -64,10 +64,13 @@ mm_segment_t enable_sacf_uaccess(void)
 {
 	mm_segment_t old_fs;
 	unsigned long asce, cr;
+	unsigned long flags;
 
 	old_fs = current->thread.mm_segment;
 	if (old_fs & 1)
 		return old_fs;
+	/* protect against a concurrent page table upgrade */
+	local_irq_save(flags);
 	current->thread.mm_segment |= 1;
 	asce = S390_lowcore.kernel_asce;
 	if (likely(old_fs == USER_DS)) {

@@ -83,6 +86,7 @@ mm_segment_t enable_sacf_uaccess(void)
 		__ctl_load(asce, 7, 7);
 		set_cpu_flag(CIF_ASCE_SECONDARY);
 	}
+	local_irq_restore(flags);
 	return old_fs;
 }
 EXPORT_SYMBOL(enable_sacf_uaccess);

@@ -70,8 +70,20 @@ static void __crst_table_upgrade(void *a
 {
 	struct mm_struct *mm = arg;
 
-	if (current->active_mm == mm)
-		set_user_asce(mm);
+	/* we must change all active ASCEs to avoid the creation of new TLBs */
+	if (current->active_mm == mm) {
+		S390_lowcore.user_asce = mm->context.asce;
+		if (current->thread.mm_segment == USER_DS) {
+			__ctl_load(S390_lowcore.user_asce, 1, 1);
+			/* Mark user-ASCE present in CR1 */
+			clear_cpu_flag(CIF_ASCE_PRIMARY);
+		}
+		if (current->thread.mm_segment == USER_DS_SACF) {
+			__ctl_load(S390_lowcore.user_asce, 7, 7);
+			/* enable_sacf_uaccess does all or nothing */
+			WARN_ON(!test_cpu_flag(CIF_ASCE_SECONDARY));
+		}
+	}
 	__tlb_flush_local();
 }