[S390] sclp: Test facility list before executing a service call.

Check if a command is available before executing. Saves some
superfluous service calls that won't succeed anyway.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

3 files changed, 18 insertions, 0 deletions

diff --git a/drivers/s390/char/sclp.h b/drivers/s390/char/sclp.h
index cb5888f7900..c7318a12585 100644
--- a/drivers/s390/char/sclp.h
+++ b/drivers/s390/char/sclp.h
@@ -79,6 +79,11 @@ struct sccb_header {
 	u16	response_code;
 } __attribute__((packed));
 
+extern u64 sclp_facilities;
+
+#define SCLP_HAS_CHP_INFO	(sclp_facilities & 0x8000000000000000ULL)
+#define SCLP_HAS_CHP_RECONFIG	(sclp_facilities & 0x2000000000000000ULL)
+
 struct gds_subvector {
 	u8	length;
 	u8	key;
diff --git a/drivers/s390/char/sclp_chp.c b/drivers/s390/char/sclp_chp.c
index a66b914519b..c68f5e7e63a 100644
--- a/drivers/s390/char/sclp_chp.c
+++ b/drivers/s390/char/sclp_chp.c
@@ -55,6 +55,8 @@ static int do_configure(sclp_cmdw_t cmd)
 	struct chp_cfg_data *data;
 	int rc;
 
+	if (!SCLP_HAS_CHP_RECONFIG)
+		return -EOPNOTSUPP;
 	/* Prepare sccb. */
 	data = (struct chp_cfg_data *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 	if (!data)
@@ -152,6 +154,8 @@ int sclp_chp_read_info(struct sclp_chp_info *info)
 	struct chp_info_data *data;
 	int rc;
 
+	if (!SCLP_HAS_CHP_INFO)
+		return -EOPNOTSUPP;
 	/* Prepare sccb. */
 	data = (struct chp_info_data *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
 	if (!data)
diff --git a/drivers/s390/char/sclp_info.c b/drivers/s390/char/sclp_info.c
index 7d21dbb12fc..a1136e05275 100644
--- a/drivers/s390/char/sclp_info.c
+++ b/drivers/s390/char/sclp_info.c
@@ -30,6 +30,8 @@ struct sclp_readinfo_sccb {
 static struct sclp_readinfo_sccb __initdata early_readinfo_sccb;
 static int __initdata early_readinfo_sccb_valid;
 
+u64 sclp_facilities;
+
 void __init sclp_readinfo_early(void)
 {
 	int ret;
@@ -70,6 +72,13 @@ void __init sclp_readinfo_early(void)
 	__ctl_clear_bit(0, 9);
 }
 
+void __init sclp_facilities_detect(void)
+{
+	if (!early_readinfo_sccb_valid)
+		return;
+	sclp_facilities = early_readinfo_sccb.facilities;
+}
+
 unsigned long long __init sclp_memory_detect(void)
 {
 	unsigned long long memsize;