s390/ftrace: fix mcount adjustment
Tony Jones reported that the ftrace self tests on s390 do not work:
<6>Testing dynamic ftrace ops #1: (0 0 0 0 0) FAILED!
<6>Testing tracer irqsoff:
<3>failed to start irqsoff tracer
<4>.. no entries found ..FAILED!
<6>Testing tracer wakeup:
<3>failed to start wakeup tracer
<4>.. no entries found ..FAILED!
<6>Testing tracer function_graph:
<4>Failed to init function_graph tracer, init returned -19
<4>FAILED!
This happens because we forgot to adjust the instruction pointer that gets
passed to the ftrace trace function by MCOUNT_INSN_SIZE.
In addition change MCOUNT_INSN_SIZE to the correct value on 31 bit.
It only worked so far because the to be patched instruction was identical.
Reported-by: Tony Jones <tonyj@suse.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
index b7931fa..bf246da 100644
--- a/arch/s390/include/asm/ftrace.h
+++ b/arch/s390/include/asm/ftrace.h
@@ -9,11 +9,6 @@
#define MCOUNT_ADDR ((long)_mcount)
-#ifdef CONFIG_64BIT
-#define MCOUNT_INSN_SIZE 12
-#else
-#define MCOUNT_INSN_SIZE 20
-#endif
static inline unsigned long ftrace_call_adjust(unsigned long addr)
{
@@ -21,4 +16,11 @@
}
#endif /* __ASSEMBLY__ */
+
+#ifdef CONFIG_64BIT
+#define MCOUNT_INSN_SIZE 12
+#else
+#define MCOUNT_INSN_SIZE 22
+#endif
+
#endif /* _ASM_S390_FTRACE_H */