s390/mm: use basic block for essa inline assembly

Use only simple inline assemblies which consist of a single basic
block if the register asm construct is being used.

Otherwise gcc would generate broken code if the compiler option
--sanitize-coverage=trace-pc would be used.

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

1 files changed, 9 insertions, 4 deletions

diff --git a/arch/s390/mm/page-states.c b/arch/s390/mm/page-states.c
index a90d45e9dfb0..3330ea124eec 100644
--- a/arch/s390/mm/page-states.c
+++ b/arch/s390/mm/page-states.c
@@ -34,20 +34,25 @@ static int __init cmma(char *str)
 }
 __setup("cmma=", cmma);
 
-void __init cmma_init(void)
+static inline int cmma_test_essa(void)
 {
         register unsigned long tmp asm("0") = 0;
         register int rc asm("1") = -EOPNOTSUPP;
 
-        if (!cmma_flag)
-                return;
         asm volatile(
                 "       .insn rrf,0xb9ab0000,%1,%1,0,0\n"
                 "0:     la      %0,0\n"
                 "1:\n"
                 EX_TABLE(0b,1b)
                 : "+&d" (rc), "+&d" (tmp));
-        if (rc)
+        return rc;
+}
+
+void __init cmma_init(void)
+{
+        if (!cmma_flag)
+                return;
+        if (cmma_test_essa())
                 cmma_flag = 0;
 }