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Revision e8129c642155616d9e2160a75f103e127c8c3708 authored by Heiko Carstens on 25 November 2010, 08:52:45 UTC, committed by Martin Schwidefsky on 25 November 2010, 08:52:59 UTC 
[S390] nmi: fix clock comparator revalidation
 
On each machine check all registers are revalidated. The save area for
the clock comparator however only contains the upper most seven bytes
of the former contents, if valid.
Therefore the machine check handler uses a store clock instruction to
get the current time and writes that to the clock comparator register
which in turn will generate an immediate timer interrupt.
However within the lowcore the expected time of the next timer
interrupt is stored. If the interrupt happens before that time the
handler won't be called. In turn the clock comparator won't be
reprogrammed and therefore the interrupt condition stays pending which
causes an interrupt loop until the expected time is reached.

On NOHZ machines this can result in unresponsive machines since the
time of the next expected interrupted can be a couple of days in the
future.

To fix this just revalidate the clock comparator register with the
expected value.
In addition the special handling for udelay must be changed as well.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
1 parent 698fd6a
Raw File
nls_koi8-ru.c 
/*
 * linux/fs/nls/nls_koi8-ru.c
 *
 * Charset koi8-ru translation based on charset koi8-u.
 * The Unicode to charset table has only exact mappings.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/nls.h>
#include <linux/errno.h>

static struct nls_table *p_nls;

static int uni2char(const wchar_t uni,
		    unsigned char *out, int boundlen)
{
	if (boundlen <= 0)
		return -ENAMETOOLONG;

	if ((uni & 0xffaf) == 0x040e || (uni & 0xffce) == 0x254c) {
		/* koi8-ru and koi8-u differ only on two characters */
		if (uni == 0x040e)
			out[0] = 0xbe;
		else if (uni == 0x045e)
			out[0] = 0xae;
		else if (uni == 0x255d || uni == 0x256c)
			return 0;
		else
			return p_nls->uni2char(uni, out, boundlen);
		return 1;
	}
	else
		/* fast path */
		return p_nls->uni2char(uni, out, boundlen);
}

static int char2uni(const unsigned char *rawstring, int boundlen,
		    wchar_t *uni)
{
	int n;

	if ((*rawstring & 0xef) != 0xae) {
		/* koi8-ru and koi8-u differ only on two characters */
		*uni = (*rawstring & 0x10) ? 0x040e : 0x045e;
		return 1;
	}

	n = p_nls->char2uni(rawstring, boundlen, uni);
	return n;
}

static struct nls_table table = {
	.charset	= "koi8-ru",
	.uni2char	= uni2char,
	.char2uni	= char2uni,
	.owner		= THIS_MODULE,
};

static int __init init_nls_koi8_ru(void)
{
	p_nls = load_nls("koi8-u");

	if (p_nls) {
		table.charset2upper = p_nls->charset2upper;
		table.charset2lower = p_nls->charset2lower;
		return register_nls(&table);
	}

	return -EINVAL;
}

static void __exit exit_nls_koi8_ru(void)
{
	unregister_nls(&table);
	unload_nls(p_nls);
}

module_init(init_nls_koi8_ru)
module_exit(exit_nls_koi8_ru)

MODULE_LICENSE("Dual BSD/GPL");
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