s390/ctlreg: add local_ctl_load() and local_ctl_store()

Add local_ctl_load() and local_ctl_store() which load and store contents
for only a single control register.

This allows for easier to read code, but also better type checking,
since __local_ctl_load() and __local_ctl_store() do not come with any
type checking at all (which will be changed with subsequent patches).

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/arch/s390/include/asm/ctlreg.h b/arch/s390/include/asm/ctlreg.h
index 09d35ab3d1ce..e8e5aef08bfd 100644
--- a/arch/s390/include/asm/ctlreg.h
+++ b/arch/s390/include/asm/ctlreg.h
@@ -69,6 +69,23 @@
 		: [_low] "i" (low), [_high] "i" (high));		\
 } while (0)
 
+static __always_inline void local_ctl_load(unsigned int cr, unsigned long *reg)
+{
+	asm volatile(
+		"	lctlg	%[cr],%[cr],%[reg]\n"
+		:
+		: [reg] "Q" (*reg), [cr] "i" (cr)
+		: "memory");
+}
+
+static __always_inline void local_ctl_store(unsigned int cr, unsigned long *reg)
+{
+	asm volatile(
+		"	stctg	%[cr],%[cr],%[reg]\n"
+		: [reg] "=Q" (*reg)
+		: [cr] "i" (cr));
+}
+
 static __always_inline void local_ctl_set_bit(unsigned int cr, unsigned int bit)
 {
 	unsigned long reg;