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authorHeiko Carstens <heiko.carstens@de.ibm.com>2013-05-13 14:48:52 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2013-05-15 13:09:09 +0200
commitaca91209775514b5a335e7ef11f1d636618590c7 (patch)
treed2bc7248e2a4451e0a68c1680106770ad64874eb /arch/s390
parentbb4b42ce0ca36af8c113587ab64b138b3cf5459c (diff)
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>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/include/asm/ftrace.h12
-rw-r--r--arch/s390/kernel/ftrace.c9
-rw-r--r--arch/s390/kernel/mcount.S2
-rw-r--r--arch/s390/kernel/mcount64.S2
4 files changed, 13 insertions, 12 deletions
diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
index b7931faaef6d..bf246dae1367 100644
--- a/arch/s390/include/asm/ftrace.h
+++ b/arch/s390/include/asm/ftrace.h
@@ -9,11 +9,6 @@ struct dyn_arch_ftrace { };
#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 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
}
#endif /* __ASSEMBLY__ */
+
+#ifdef CONFIG_64BIT
+#define MCOUNT_INSN_SIZE 12
+#else
+#define MCOUNT_INSN_SIZE 22
+#endif
+
#endif /* _ASM_S390_FTRACE_H */
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 78bdf0e5dff7..e3043aef87a9 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -16,12 +16,6 @@
#include <trace/syscall.h>
#include <asm/asm-offsets.h>
-#ifdef CONFIG_64BIT
-#define MCOUNT_OFFSET_RET 12
-#else
-#define MCOUNT_OFFSET_RET 22
-#endif
-
#ifdef CONFIG_DYNAMIC_FTRACE
void ftrace_disable_code(void);
@@ -155,9 +149,10 @@ unsigned long __kprobes prepare_ftrace_return(unsigned long parent,
if (unlikely(atomic_read(&current->tracing_graph_pause)))
goto out;
+ ip = (ip & PSW_ADDR_INSN) - MCOUNT_INSN_SIZE;
if (ftrace_push_return_trace(parent, ip, &trace.depth, 0) == -EBUSY)
goto out;
- trace.func = (ip & PSW_ADDR_INSN) - MCOUNT_OFFSET_RET;
+ trace.func = ip;
/* Only trace if the calling function expects to. */
if (!ftrace_graph_entry(&trace)) {
current->curr_ret_stack--;
diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S
index 4567ce20d900..08dcf21cb8df 100644
--- a/arch/s390/kernel/mcount.S
+++ b/arch/s390/kernel/mcount.S
@@ -7,6 +7,7 @@
#include <linux/linkage.h>
#include <asm/asm-offsets.h>
+#include <asm/ftrace.h>
.section .kprobes.text, "ax"
@@ -33,6 +34,7 @@ ENTRY(ftrace_caller)
la %r2,0(%r14)
st %r0,__SF_BACKCHAIN(%r15)
la %r3,0(%r3)
+ ahi %r2,-MCOUNT_INSN_SIZE
l %r14,0b-0b(%r1)
l %r14,0(%r14)
basr %r14,%r14
diff --git a/arch/s390/kernel/mcount64.S b/arch/s390/kernel/mcount64.S
index 11332193db30..1c52eae3396a 100644
--- a/arch/s390/kernel/mcount64.S
+++ b/arch/s390/kernel/mcount64.S
@@ -7,6 +7,7 @@
#include <linux/linkage.h>
#include <asm/asm-offsets.h>
+#include <asm/ftrace.h>
.section .kprobes.text, "ax"
@@ -29,6 +30,7 @@ ENTRY(ftrace_caller)
stg %r1,__SF_BACKCHAIN(%r15)
lgr %r2,%r14
lg %r3,168(%r15)
+ aghi %r2,-MCOUNT_INSN_SIZE
larl %r14,ftrace_trace_function
lg %r14,0(%r14)
basr %r14,%r14