s390: enable processes for mio instructions

Allow for userspace to use PCI MIO instructions.

Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/include/asm/pci_insn.h

@@ -143,4 +143,14 @@ static inline int zpci_set_irq_ctrl(u16 ctl, u8 isc)
 	return __zpci_set_irq_ctrl(ctl, isc, &iib);
 }
 
+#ifdef CONFIG_PCI
+static inline void enable_mio_ctl(void)
+{
+	if (static_branch_likely(&have_mio))
+		__ctl_set_bit(2, 5);
+}
+#else /* CONFIG_PCI */
+static inline void enable_mio_ctl(void) {}
+#endif /* CONFIG_PCI */
+
 #endif

arch/s390/kernel/early.c

@@ -30,6 +30,7 @@
 #include <asm/sclp.h>
 #include <asm/facility.h>
 #include <asm/boot_data.h>
+#include <asm/pci_insn.h>
 #include "entry.h"
 
 /*
@@ -235,6 +236,7 @@ static __init void detect_machine_facilities(void)
 		clock_comparator_max = -1ULL >> 1;
 		__ctl_set_bit(0, 53);
 	}
+	enable_mio_ctl();
 }
 
 static inline void save_vector_registers(void)