[S390] Use diag308 subcodes 3 and 6 for reboot and dump when possible.

This patch fixes a problem with the following scenario:
 1. Linux booted from DASD "A"
 2. Reboot from DASD "B" using "/sys/firmware/reipl/ccw/device"
 3. Reboot DASD "B"
Without this patch in step 3 on newer s390 systems under LPAR instead of
DASD "B", DASD "A" will be booted. The reason is that in step 2 we use CCW
reipl and in step 3 we use DIAG308 (subcode 3) reipl. DIAG308 does not
notice the CCW reipl and still thinks that it has to reboot DASD "A".
Before applying this fix, ensure to have MCF RJ9967101E or z9 GA3 base driver
installed.

Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

2 files changed, 12 insertions, 6 deletions

diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 14bdde9def40..db28cca81fef 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -595,7 +595,9 @@ static int reipl_set_type(enum ipl_type type)
 
 	switch(type) {
 	case IPL_TYPE_CCW:
-		if (MACHINE_IS_VM)
+		if (diag308_set_works)
+			reipl_method = REIPL_METHOD_CCW_DIAG;
+		else if (MACHINE_IS_VM)
 			reipl_method = REIPL_METHOD_CCW_VM;
 		else
 			reipl_method = REIPL_METHOD_CCW_CIO;
@@ -659,8 +661,6 @@ void reipl_run(struct shutdown_trigger *trigger)
 	switch (reipl_method) {
 	case REIPL_METHOD_CCW_CIO:
 		devid.devno = reipl_block_ccw->ipl_info.ccw.devno;
-		if (ipl_info.type == IPL_TYPE_CCW && devid.devno == ipl_devno)
-			diag308(DIAG308_IPL, NULL);
 		devid.ssid  = 0;
 		reipl_ccw_dev(&devid);
 		break;
@@ -745,6 +745,7 @@ static int __init reipl_ccw_init(void)
 	reipl_block_ccw->hdr.version = IPL_PARM_BLOCK_VERSION;
 	reipl_block_ccw->hdr.blk0_len = IPL_PARM_BLK0_CCW_LEN;
 	reipl_block_ccw->hdr.pbt = DIAG308_IPL_TYPE_CCW;
+	reipl_block_ccw->hdr.flags = DIAG308_FLAGS_LP_VALID;
 	/* check if read scp info worked and set loadparm */
 	if (sclp_ipl_info.is_valid)
 		memcpy(reipl_block_ccw->ipl_info.ccw.load_param,
@@ -753,8 +754,7 @@ static int __init reipl_ccw_init(void)
 		/* read scp info failed: set empty loadparm (EBCDIC blanks) */
 		memset(reipl_block_ccw->ipl_info.ccw.load_param, 0x40,
 		       LOADPARM_LEN);
-	/* FIXME: check for diag308_set_works when enabling diag ccw reipl */
-	if (!MACHINE_IS_VM)
+	if (!MACHINE_IS_VM && !diag308_set_works)
 		sys_reipl_ccw_loadparm_attr.attr.mode = S_IRUGO;
 	if (ipl_info.type == IPL_TYPE_CCW)
 		reipl_block_ccw->ipl_info.ccw.devno = ipl_devno;
@@ -876,7 +876,9 @@ static int dump_set_type(enum dump_type type)
 		return -EINVAL;
 	switch (type) {
 	case DUMP_TYPE_CCW:
-		if (MACHINE_IS_VM)
+		if (diag308_set_works)
+			dump_method = DUMP_METHOD_CCW_DIAG;
+		else if (MACHINE_IS_VM)
 			dump_method = DUMP_METHOD_CCW_VM;
 		else
 			dump_method = DUMP_METHOD_CCW_CIO;
diff --git a/include/asm-s390/ipl.h b/include/asm-s390/ipl.h
index d0dcc9c5f7c3..c1b2e50392bb 100644
--- a/include/asm-s390/ipl.h
+++ b/include/asm-s390/ipl.h
@@ -143,6 +143,10 @@ enum diag308_opt {
 	DIAG308_IPL_OPT_DUMP	= 0x20,
 };
 
+enum diag308_flags {
+	DIAG308_FLAGS_LP_VALID	= 0x80,
+};
+
 enum diag308_rc {
 	DIAG308_RC_OK	= 1,
 };