[PATCH] s390: machine check handler bugs

The new machine check handler still has a few bugs.

1) The system entry time has to be stored in the machine check handler,

2) the machine check return psw may not be stored at the usual place
   because it might overwrite the return psw of the interrupted context,

3) the return address for the call to s390_handle_mcck in the i/o interrupt
   handler is not correct,

4) the system call cleanup has to take the different save area of the
   machine check handler into account,

5) the machine check handler may not call UPDATE_VTIME before
   CREATE_STACK_FRAME, and

6) the io leave path needs a critical section cleanup to make sure that the
   TIF_MCCK_PENDING bit is really checked before switching back to user space.

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>

1 files changed, 6 insertions, 2 deletions

diff --git a/include/asm-s390/lowcore.h b/include/asm-s390/lowcore.h
index afe6a9f9b0ae..c6f51c9ce3ff 100644
--- a/include/asm-s390/lowcore.h
+++ b/include/asm-s390/lowcore.h
@@ -68,6 +68,7 @@
 #define __LC_SYSTEM_TIMER               0x270
 #define __LC_LAST_UPDATE_CLOCK          0x278
 #define __LC_STEAL_CLOCK                0x280
+#define __LC_RETURN_MCCK_PSW            0x288
 #define __LC_KERNEL_STACK               0xC40
 #define __LC_THREAD_INFO                0xC44
 #define __LC_ASYNC_STACK                0xC48
@@ -90,6 +91,7 @@
 #define __LC_SYSTEM_TIMER               0x278
 #define __LC_LAST_UPDATE_CLOCK          0x280
 #define __LC_STEAL_CLOCK                0x288
+#define __LC_RETURN_MCCK_PSW            0x290
 #define __LC_KERNEL_STACK               0xD40
 #define __LC_THREAD_INFO                0xD48
 #define __LC_ASYNC_STACK                0xD50
@@ -196,7 +198,8 @@ struct _lowcore
         __u64        system_timer;             /* 0x270 */
         __u64        last_update_clock;        /* 0x278 */
         __u64        steal_clock;              /* 0x280 */
-        __u8         pad8[0xc00-0x288];        /* 0x288 */
+        psw_t        return_mcck_psw;          /* 0x288 */
+        __u8         pad8[0xc00-0x290];        /* 0x290 */
 
         /* System info area */
         __u32        save_area[16];            /* 0xc00 */
@@ -285,7 +288,8 @@ struct _lowcore
         __u64        system_timer;             /* 0x278 */
         __u64        last_update_clock;        /* 0x280 */
         __u64        steal_clock;              /* 0x288 */
-        __u8         pad8[0xc00-0x290];        /* 0x290 */
+        psw_t        return_mcck_psw;          /* 0x290 */
+        __u8         pad8[0xc00-0x2a0];        /* 0x2a0 */
         /* System info area */
         __u64        save_area[16];            /* 0xc00 */
         __u8         pad9[0xd40-0xc80];        /* 0xc80 */