From aca91209775514b5a335e7ef11f1d636618590c7 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Mon, 13 May 2013 14:48:52 +0200 Subject: 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 Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/mcount.S | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/s390/kernel/mcount.S') 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 #include +#include .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 -- cgit