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| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2013-05-13 14:48:52 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2013-05-15 13:09:09 +0200 |
| commit | aca91209775514b5a335e7ef11f1d636618590c7 (patch) | |
| tree | d2bc7248e2a4451e0a68c1680106770ad64874eb /arch/s390/kernel/ftrace.c | |
| parent | bb4b42ce0ca36af8c113587ab64b138b3cf5459c (diff) | |
| download | linux-aca91209775514b5a335e7ef11f1d636618590c7.tar.bz2 | |
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/kernel/ftrace.c')
| -rw-r--r-- | arch/s390/kernel/ftrace.c | 9 |
1 files changed, 2 insertions, 7 deletions
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(¤t->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--; |