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[S390] console flush on panic / reboot

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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
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26
drivers/s390/char/sclp_vt220.c
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@@ -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;
}