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[PATCH] s390: instruction processing damage handling

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In case of an instruction processing damage (IPD) machine check in kernel mode
the resulting action is always to stop the kernel.  This is not necessarily
the best solution since a retry of the failing instruction might succeed.  Add
logic to retry the instruction if no more than 30 instruction processing
damage checks occured in the last 5 minutes.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Heiko Carstens 2006-04-27 18:40:23 -07:00 committed by Linus Torvalds
parent 9b5dec1aa0
commit b73d40c617
1 changed files with 28 additions and 5 deletions
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33
drivers/s390/s390mach.c
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@ -362,12 +362,19 @@ s390_revalidate_registers(struct mci *mci)
return kill_task;
}
#define MAX_IPD_COUNT 29
#define MAX_IPD_TIME (5 * 60 * 100 * 1000) /* 5 minutes */
/*
* machine check handler.
*/
void
s390_do_machine_check(struct pt_regs *regs)
{
static DEFINE_SPINLOCK(ipd_lock);
static unsigned long long last_ipd;
static int ipd_count;
unsigned long long tmp;
struct mci *mci;
struct mcck_struct *mcck;
int umode;
@ -404,11 +411,27 @@ s390_do_machine_check(struct pt_regs *regs)
s390_handle_damage("processing backup machine "
"check with damage.");
}
if (!umode)
s390_handle_damage("processing backup machine "
"check in kernel mode.");
mcck->kill_task = 1;
mcck->mcck_code = *(unsigned long long *) mci;
/*
* Nullifying exigent condition, therefore we might
* retry this instruction.
*/
spin_lock(&ipd_lock);
tmp = get_clock();
if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
ipd_count++;
else
ipd_count = 1;
last_ipd = tmp;
if (ipd_count == MAX_IPD_COUNT)
s390_handle_damage("too many ipd retries.");
spin_unlock(&ipd_lock);
}
else {
/* Processing damage -> stopping machine */