[S390] avoid STCKF if running in ESA mode

In ESA mode STCKF is not defined even if the facility bit is enabled.
To prevent an illegal operation we must also check if we run a 64 bit kernel.
To make the check perform well add the STCKF bit to the machine flags.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

3 files changed, 6 insertions, 1 deletions

diff --git a/arch/s390/include/asm/setup.h b/arch/s390/include/asm/setup.h
index 5a099714df04..097183c70407 100644
--- a/arch/s390/include/asm/setup.h
+++ b/arch/s390/include/asm/setup.h
@@ -82,6 +82,7 @@ extern unsigned int user_mode;
 #define MACHINE_FLAG_LPAR       (1UL << 12)
 #define MACHINE_FLAG_SPP        (1UL << 13)
 #define MACHINE_FLAG_TOPOLOGY   (1UL << 14)
+#define MACHINE_FLAG_STCKF      (1UL << 15)
 
 #define MACHINE_IS_VM           (S390_lowcore.machine_flags & MACHINE_FLAG_VM)
 #define MACHINE_IS_KVM          (S390_lowcore.machine_flags & MACHINE_FLAG_KVM)
@@ -100,6 +101,7 @@ extern unsigned int user_mode;
 #define MACHINE_HAS_PFMF        (0)
 #define MACHINE_HAS_SPP         (0)
 #define MACHINE_HAS_TOPOLOGY    (0)
+#define MACHINE_HAS_STCKF       (0)
 #else /* __s390x__ */
 #define MACHINE_HAS_IEEE        (1)
 #define MACHINE_HAS_CSP         (1)
@@ -111,6 +113,7 @@ extern unsigned int user_mode;
 #define MACHINE_HAS_PFMF        (S390_lowcore.machine_flags & MACHINE_FLAG_PFMF)
 #define MACHINE_HAS_SPP         (S390_lowcore.machine_flags & MACHINE_FLAG_SPP)
 #define MACHINE_HAS_TOPOLOGY    (S390_lowcore.machine_flags & MACHINE_FLAG_TOPOLOGY)
+#define MACHINE_HAS_STCKF       (S390_lowcore.machine_flags & MACHINE_FLAG_STCKF)
 #endif /* __s390x__ */
 
 #define ZFCPDUMP_HSA_SIZE       (32UL<<20)
diff --git a/arch/s390/include/asm/timex.h b/arch/s390/include/asm/timex.h
index d610bef9c5e9..c447a27a7fdb 100644
--- a/arch/s390/include/asm/timex.h
+++ b/arch/s390/include/asm/timex.h
@@ -90,7 +90,7 @@ static inline unsigned long long get_clock_fast(void)
 {
         unsigned long long clk;
 
-        if (test_facility(25))
+        if (MACHINE_HAS_STCKF)
                 asm volatile(".insn     s,0xb27c0000,%0" : "=Q" (clk) : : "cc");
         else
                 clk = get_clock();
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 37394b3413e2..c9ffe0025197 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -390,6 +390,8 @@ static __init void detect_machine_facilities(void)
                 S390_lowcore.machine_flags |= MACHINE_FLAG_MVCOS;
         if (test_facility(40))
                 S390_lowcore.machine_flags |= MACHINE_FLAG_SPP;
+        if (test_facility(25))
+                S390_lowcore.machine_flags |= MACHINE_FLAG_STCKF;
 #endif
 }