[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>

5 files changed, 20 insertions, 0 deletions

diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 9fcf3f1..e6289ee 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -275,6 +275,7 @@ void __init startup_init(void)
 	sort_main_extable();
 	setup_lowcore_early();
 	sclp_readinfo_early();
+	sclp_facilities_detect();
 	memsize = sclp_memory_detect();
 #ifndef CONFIG_64BIT
 	/*
diff --git a/drivers/s390/char/sclp.h b/drivers/s390/char/sclp.h
index cb5888f..c7318a1 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 a66b914..c68f5e7 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 7d21dbb..a1136e0 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;
diff --git a/include/asm-s390/sclp.h b/include/asm-s390/sclp.h
index ddfaa8d..cb9faf1 100644
--- a/include/asm-s390/sclp.h
+++ b/include/asm-s390/sclp.h
@@ -28,6 +28,7 @@ struct sclp_ipl_info {
 };
 
 void sclp_readinfo_early(void);
+void sclp_facilities_detect(void);
 unsigned long long sclp_memory_detect(void);
 int sclp_sdias_blk_count(void);
 int sclp_sdias_copy(void *dest, int blk_num, int nr_blks);