[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: Holger Smolinski <Holger.Smolinski@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Holger Smolinski 2008-10-10 21:33:27 +02:00 committed by Martin Schwidefsky
parent 15e86b0c75
commit 2332ce1a97
4 changed files with 86 additions and 18 deletions

View file

@ -21,6 +21,7 @@
#include <linux/console.h>
#include <linux/interrupt.h>
#include <linux/err.h>
#include <linux/reboot.h>
#include <linux/slab.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
* disabled, endless loop.
* panic() calls con3215_flush through a panic_notifier
* before the system enters a disabled, endless loop.
*/
static void
con3215_unblank(void)
con3215_flush(void)
{
struct raw3215_info *raw;
unsigned long flags;
@ -790,6 +791,23 @@ con3215_unblank(void)
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
*/
@ -797,7 +815,6 @@ static struct console con3215 = {
.name = "ttyS",
.write = con3215_write,
.device = con3215_device,
.unblank = con3215_unblank,
.flags = CON_PRINTBUFFER,
};
@ -859,6 +876,8 @@ con3215_init(void)
raw3215[0] = NULL;
return -ENODEV;
}
atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
register_reboot_notifier(&on_reboot_nb);
register_console(&con3215);
return 0;
}

View file

@ -15,6 +15,7 @@
#include <linux/list.h>
#include <linux/types.h>
#include <linux/err.h>
#include <linux/reboot.h>
#include <asm/ccwdev.h>
#include <asm/cio.h>
@ -528,11 +529,11 @@ con3270_wait_write(struct con3270 *cp)
}
/*
* panic() calls console_unblank before the system enters a
* disabled, endless loop.
* panic() calls con3270_flush through a panic_notifier
* before the system enters a disabled, endless loop.
*/
static void
con3270_unblank(void)
con3270_flush(void)
{
struct con3270 *cp;
unsigned long flags;
@ -554,6 +555,23 @@ con3270_unblank(void)
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
*/
@ -561,7 +579,6 @@ static struct console con3270 = {
.name = "tty3270",
.write = con3270_write,
.device = con3270_device,
.unblank = con3270_unblank,
.flags = CON_PRINTBUFFER,
};
@ -623,6 +640,8 @@ con3270_init(void)
condev->cline->len = 0;
con3270_create_status(condev);
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);
return 0;
}

View file

@ -16,6 +16,7 @@
#include <linux/bootmem.h>
#include <linux/termios.h>
#include <linux/err.h>
#include <linux/reboot.h>
#include "sclp.h"
#include "sclp_rw.h"
@ -172,7 +173,7 @@ sclp_console_device(struct console *c, int *index)
* will be flushed to the SCLP.
*/
static void
sclp_console_unblank(void)
sclp_console_flush(void)
{
unsigned long flags;
@ -188,6 +189,24 @@ sclp_console_unblank(void)
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
* give printk necessary information
@ -197,7 +216,6 @@ static struct console sclp_console =
.name = sclp_console_name,
.write = sclp_console_write,
.device = sclp_console_device,
.unblank = sclp_console_unblank,
.flags = CON_PRINTBUFFER,
.index = 0 /* ttyS0 */
};
@ -241,6 +259,8 @@ sclp_console_init(void)
sclp_con_width_htab = 8;
/* 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);
return 0;
}

View file

@ -24,6 +24,8 @@
#include <linux/bootmem.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/reboot.h>
#include <asm/uaccess.h>
#include "sclp.h"
@ -743,24 +745,30 @@ sclp_vt220_con_device(struct console *c, int *index)
return sclp_vt220_driver;
}
/*
* This routine is called from panic when the kernel is going to give up.
* We have to make sure that all buffers will be flushed to the SCLP.
* Note that this function may be called from within an interrupt context.
*/
static void
sclp_vt220_con_unblank(void)
static int
sclp_vt220_notify(struct notifier_block *self,
unsigned long event, void *data)
{
__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 */
static struct console sclp_vt220_console =
{
.name = SCLP_VT220_CONSOLE_NAME,
.write = sclp_vt220_con_write,
.device = sclp_vt220_con_device,
.unblank = sclp_vt220_con_unblank,
.flags = CON_PRINTBUFFER,
.index = SCLP_VT220_CONSOLE_INDEX
};
@ -776,6 +784,8 @@ sclp_vt220_con_init(void)
if (rc)
return rc;
/* Attach linux console */
atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
register_reboot_notifier(&on_reboot_nb);
register_console(&sclp_vt220_console);
return 0;
}