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s390/dasd: fix diag 0x250 inline assembly 

git commit 1ec2772e0c ("s390/diag: add a statistic for diagnose
calls") added function calls to gather diagnose statistics.

In case of the dasd diag driver the function call was added between a
register asm statement which initialized register r2 and the inline
assembly itself.  The function call clobbers the contents of register
r2 and therefore the diag 0x250 call behaves in a more or less random
way.

Fix this by extracting the function call into a separate function like
we do everywhere else.

Fixes: 1ec2772e0c ("s390/diag: add a statistic for diagnose calls")
Cc: <stable@vger.kernel.org> # 4.4+
Reported-and-tested-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Heiko Carstens 2016-03-01 12:58:06 +01:00 committed by Martin Schwidefsky
parent f691b77b1f
commit ce0c12b633
1 changed files with 7 additions and 2 deletions
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9
drivers/s390/block/dasd_diag.c
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@ -67,7 +67,7 @@ static const u8 DASD_DIAG_CMS1[] = { 0xc3, 0xd4, 0xe2, 0xf1 };/* EBCDIC CMS1 */
* and function code cmd.
* In case of an exception return 3. Otherwise return result of bitwise OR of
* resulting condition code and DIAG return code. */
static inline int dia250(void *iob, int cmd)
static inline int __dia250(void *iob, int cmd)
{
register unsigned long reg2 asm ("2") = (unsigned long) iob;
typedef union {
@ -77,7 +77,6 @@ static inline int dia250(void *iob, int cmd)
int rc;
rc = 3;
diag_stat_inc(DIAG_STAT_X250);
asm volatile(
" diag 2,%2,0x250\n"
"0: ipm %0\n"
@ -91,6 +90,12 @@ static inline int dia250(void *iob, int cmd)
return rc;
}
static inline int dia250(void *iob, int cmd)
{
diag_stat_inc(DIAG_STAT_X250);
return __dia250(iob, cmd);
}
/* Initialize block I/O to DIAG device using the specified blocksize and
* block offset. On success, return zero and set end_block to contain the
* number of blocks on the device minus the specified offset. Return non-zero