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Commit ce0c12b6 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
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s390/dasd: fix diag 0x250 inline assembly 



git commit 1ec2772e ("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: 1ec2772e ("s390/diag: add a statistic for diagnose calls")
Cc: <stable@vger.kernel.org> # 4.4+
Reported-and-tested-by: default avatarStefan Haberland <sth@linux.vnet.ibm.com>
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent f691b77b

drivers/s390/block/dasd_diag.c

+7 −2
Original line number Diff line number Diff line
@@ -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