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Commit 2332ce1a authored by Holger Smolinski's avatar Holger Smolinski Committed by Martin Schwidefsky
Browse files

[S390] console flush on panic / reboot 



The s390 console drivers use the unblank callback of the console
structure to flush the console buffer. In case of a panic or a
reboot the CPU doing the callback can block on the console i/o.
The other CPUs in the system continue to work. For panic this is
not a good idea.

Replace the unblank callback with proper panic/reboot notifier.
These get called after all but one CPU have been stopped.

Signed-off-by: default avatarHolger Smolinski <Holger.Smolinski@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 15e86b0c

drivers/s390/char/con3215.c

+23 −4
Original line number Original line Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/console.h>

#include <linux/console.h>

#include <linux/interrupt.h>

#include <linux/interrupt.h>

#include <linux/err.h>

#include <linux/err.h>

#include <linux/reboot.h>





#include <linux/slab.h>

#include <linux/slab.h>

#include <linux/bootmem.h>

#include <linux/bootmem.h>
@@ -775,11 +776,11 @@ static struct tty_driver *con3215_device(struct console *c, int *index) 
}

}





/*

/*

 * panic() calls console_unblank before the system enters a

 * panic() calls con3215_flush through a panic_notifier

 * disabled, endless loop.

 * before the system enters a disabled, endless loop.

 */

 */

static void

static void

con3215_unblank(void)

con3215_flush(void)

{

{

	struct raw3215_info *raw;

	struct raw3215_info *raw;

	unsigned long flags;

	unsigned long flags;
@@ -790,6 +791,23 @@ con3215_unblank(void) 
	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);

	spin_unlock_irqrestore(get_ccwdev_lock(raw->cdev), flags);

}

}





static int con3215_notify(struct notifier_block *self,

			  unsigned long event, void *data)

{

	con3215_flush();

	return NOTIFY_OK;

}



static struct notifier_block on_panic_nb = {

	.notifier_call = con3215_notify,

	.priority = 0,

};



static struct notifier_block on_reboot_nb = {

	.notifier_call = con3215_notify,

	.priority = 0,

};



/*

/*

 *  The console structure for the 3215 console

 *  The console structure for the 3215 console

 */

 */
@@ -797,7 +815,6 @@ static struct console con3215 = { 
	.name	 = "ttyS",

	.name	 = "ttyS",

	.write	 = con3215_write,

	.write	 = con3215_write,

	.device	 = con3215_device,

	.device	 = con3215_device,

	.unblank = con3215_unblank,

	.flags	 = CON_PRINTBUFFER,

	.flags	 = CON_PRINTBUFFER,

};

};
@@ -859,6 +876,8 @@ con3215_init(void) 
		raw3215[0] = NULL;

		raw3215[0] = NULL;

		return -ENODEV;

		return -ENODEV;

	}

	}

	atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);

	register_reboot_notifier(&on_reboot_nb);

	register_console(&con3215);

	register_console(&con3215);

	return 0;

	return 0;

}

}

drivers/s390/char/con3270.c

+23 −4
Original line number Original line Diff line number Diff line
@@ -15,6 +15,7 @@ 
#include <linux/list.h>

#include <linux/list.h>

#include <linux/types.h>

#include <linux/types.h>

#include <linux/err.h>

#include <linux/err.h>

#include <linux/reboot.h>





#include <asm/ccwdev.h>

#include <asm/ccwdev.h>

#include <asm/cio.h>

#include <asm/cio.h>
@@ -528,11 +529,11 @@ con3270_wait_write(struct con3270 *cp) 
}

}





/*

/*

 * panic() calls console_unblank before the system enters a

 * panic() calls con3270_flush through a panic_notifier

 * disabled, endless loop.

 * before the system enters a disabled, endless loop.

 */

 */

static void

static void

con3270_unblank(void)

con3270_flush(void)

{

{

	struct con3270 *cp;

	struct con3270 *cp;

	unsigned long flags;

	unsigned long flags;
@@ -554,6 +555,23 @@ con3270_unblank(void) 
	spin_unlock_irqrestore(&cp->view.lock, flags);

	spin_unlock_irqrestore(&cp->view.lock, flags);

}

}





static int con3270_notify(struct notifier_block *self,

			  unsigned long event, void *data)

{

	con3270_flush();

	return NOTIFY_OK;

}



static struct notifier_block on_panic_nb = {

	.notifier_call = con3270_notify,

	.priority = 0,

};



static struct notifier_block on_reboot_nb = {

	.notifier_call = con3270_notify,

	.priority = 0,

};



/*

/*

 *  The console structure for the 3270 console

 *  The console structure for the 3270 console

 */

 */
@@ -561,7 +579,6 @@ static struct console con3270 = { 
	.name	 = "tty3270",

	.name	 = "tty3270",

	.write	 = con3270_write,

	.write	 = con3270_write,

	.device	 = con3270_device,

	.device	 = con3270_device,

	.unblank = con3270_unblank,

	.flags	 = CON_PRINTBUFFER,

	.flags	 = CON_PRINTBUFFER,

};

};
@@ -623,6 +640,8 @@ con3270_init(void) 
	condev->cline->len = 0;

	condev->cline->len = 0;

	con3270_create_status(condev);

	con3270_create_status(condev);

	condev->input = alloc_string(&condev->freemem, 80);

	condev->input = alloc_string(&condev->freemem, 80);

	atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);

	register_reboot_notifier(&on_reboot_nb);

	register_console(&con3270);

	register_console(&con3270);

	return 0;

	return 0;

}

}

drivers/s390/char/sclp_con.c

+22 −2
Original line number Original line Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <linux/bootmem.h>

#include <linux/bootmem.h>

#include <linux/termios.h>

#include <linux/termios.h>

#include <linux/err.h>

#include <linux/err.h>

#include <linux/reboot.h>





#include "sclp.h"

#include "sclp.h"

#include "sclp_rw.h"

#include "sclp_rw.h"
@@ -172,7 +173,7 @@ sclp_console_device(struct console *c, int *index) 
 * will be flushed to the SCLP.

 * will be flushed to the SCLP.

 */

 */

static void

static void

sclp_console_unblank(void)

sclp_console_flush(void)

{

{

	unsigned long flags;

	unsigned long flags;
@@ -188,6 +189,24 @@ sclp_console_unblank(void) 
	spin_unlock_irqrestore(&sclp_con_lock, flags);

	spin_unlock_irqrestore(&sclp_con_lock, flags);

}

}





static int

sclp_console_notify(struct notifier_block *self,

			  unsigned long event, void *data)

{

	sclp_console_flush();

	return NOTIFY_OK;

}



static struct notifier_block on_panic_nb = {

	.notifier_call = sclp_console_notify,

	.priority = 1,

};



static struct notifier_block on_reboot_nb = {

	.notifier_call = sclp_console_notify,

	.priority = 1,

};



/*

/*

 * used to register the SCLP console to the kernel and to

 * used to register the SCLP console to the kernel and to

 * give printk necessary information

 * give printk necessary information
@@ -197,7 +216,6 @@ static struct console sclp_console = 
	.name = sclp_console_name,

	.name = sclp_console_name,

	.write = sclp_console_write,

	.write = sclp_console_write,

	.device = sclp_console_device,

	.device = sclp_console_device,

	.unblank = sclp_console_unblank,

	.flags = CON_PRINTBUFFER,

	.flags = CON_PRINTBUFFER,

	.index = 0 /* ttyS0 */

	.index = 0 /* ttyS0 */

};

};
@@ -241,6 +259,8 @@ sclp_console_init(void) 
	sclp_con_width_htab = 8;

	sclp_con_width_htab = 8;





	/* enable printk-access to this driver */

	/* enable printk-access to this driver */

	atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);

	register_reboot_notifier(&on_reboot_nb);

	register_console(&sclp_console);

	register_console(&sclp_console);

	return 0;

	return 0;

}

}

drivers/s390/char/sclp_vt220.c

+18 −8
Original line number Original line Diff line number Diff line
@@ -24,6 +24,8 @@ 
#include <linux/bootmem.h>

#include <linux/bootmem.h>

#include <linux/interrupt.h>

#include <linux/interrupt.h>

#include <linux/init.h>

#include <linux/init.h>

#include <linux/reboot.h>



#include <asm/uaccess.h>

#include <asm/uaccess.h>

#include "sclp.h"

#include "sclp.h"
@@ -743,24 +745,30 @@ sclp_vt220_con_device(struct console *c, int *index) 
	return sclp_vt220_driver;

	return sclp_vt220_driver;

}

}





/*

static int

 * This routine is called from panic when the kernel is going to give up.

sclp_vt220_notify(struct notifier_block *self,

 * We have to make sure that all buffers will be flushed to the SCLP.

			  unsigned long event, void *data)

 * Note that this function may be called from within an interrupt context.

 */

static void

sclp_vt220_con_unblank(void)

{

{

	__sclp_vt220_flush_buffer();

	__sclp_vt220_flush_buffer();

	return NOTIFY_OK;

}

}





static struct notifier_block on_panic_nb = {

	.notifier_call = sclp_vt220_notify,

	.priority = 1,

};



static struct notifier_block on_reboot_nb = {

	.notifier_call = sclp_vt220_notify,

	.priority = 1,

};



/* Structure needed to register with printk */

/* Structure needed to register with printk */

static struct console sclp_vt220_console =

static struct console sclp_vt220_console =

{

{

	.name = SCLP_VT220_CONSOLE_NAME,

	.name = SCLP_VT220_CONSOLE_NAME,

	.write = sclp_vt220_con_write,

	.write = sclp_vt220_con_write,

	.device = sclp_vt220_con_device,

	.device = sclp_vt220_con_device,

	.unblank = sclp_vt220_con_unblank,

	.flags = CON_PRINTBUFFER,

	.flags = CON_PRINTBUFFER,

	.index = SCLP_VT220_CONSOLE_INDEX

	.index = SCLP_VT220_CONSOLE_INDEX

};

};
@@ -776,6 +784,8 @@ sclp_vt220_con_init(void) 
	if (rc)

	if (rc)

		return rc;

		return rc;

	/* Attach linux console */

	/* Attach linux console */

	atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);

	register_reboot_notifier(&on_reboot_nb);

	register_console(&sclp_vt220_console);

	register_console(&sclp_vt220_console);

	return 0;

	return 0;

}

}