The patch titled
s390: instruction processing damage handling
has been added to the -mm tree. Its filename is
s390-instruction-processing-damage-handling.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
From: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/s390/s390mach.c | 33 ++++++++++++++++++++++++++++-----
1 files changed, 28 insertions(+), 5 deletions(-)
diff -puN drivers/s390/s390mach.c~s390-instruction-processing-damage-handling drivers/s390/s390mach.c
--- 25/drivers/s390/s390mach.c~s390-instruction-processing-damage-handling Mon Apr 24 16:46:09 2006
+++ 25-akpm/drivers/s390/s390mach.c Mon Apr 24 16:46:09 2006
@@ -362,12 +362,19 @@ s390_revalidate_registers(struct mci *mc
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 *re
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 */
_
Patches currently in -mm which might be from heiko.carstens@xxxxxxxxxx are
s390-make-qeth-buildable.patch
ipv4-inet_init-fs_initcall.patch
s390-bug-in-setup_rt_frame.patch
s390-instruction-processing-damage-handling.patch
rcu-introduce-rcu_soon_pending-interface.patch
s390-exploit-rcu_soon_pending-interface.patch
-
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