On Thu, Jan 20, 2011 at 7:03 PM, Sergei Shtylyov <sshtylyov@xxxxxxxxxx> wrote: > Hello. > > On 19-01-2011 22:28, Wu Zhangjin wrote: > >> trace.func should be set to the recorded ip of the mcount calling site >> in the __mcount_loc section to filter the function entries configured >> through the tracing/set_graph_function interface, but before, this is >> set to the self_ra(the return address of mcount), which has made >> set_graph_function not work as expects. > > Expected? Yeah ;-) > >> This fixes it via calculating the right recorded ip in the __mcount_loc >> section and assign it to trace.func. > >> Reported-by: Zhiping Zhong<xzhong86@xxxxxxx> >> Signed-off-by: Wu Zhangjin<wuzhangjin@xxxxxxxxx> >> --- >> arch/mips/kernel/ftrace.c | 11 +++++++++-- >> 1 files changed, 9 insertions(+), 2 deletions(-) > >> diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c >> index bc91e4a..62775d7 100644 >> --- a/arch/mips/kernel/ftrace.c >> +++ b/arch/mips/kernel/ftrace.c > > [...] >> >> @@ -304,7 +304,14 @@ void prepare_ftrace_return(unsigned long >> *parent_ra_addr, unsigned long self_ra, >> return; >> } >> >> - trace.func = self_ra; >> + /* >> + * Get the recorded ip of the current mcount calling site in the >> + * __mcount_loc section, which will be used to filter the function >> + * entries configured through the tracing/set_graph_function >> interface. >> + */ >> + >> + insns = (in_kernel_space(self_ra)) ? 2 : (MCOUNT_OFFSET_INSNS + >> 1); > > Unneeded parens. ok. > >> + trace.func = self_ra - (MCOUNT_INSN_SIZE * insns); > > Here too. ok. Thanks, Wu Zhangjin > > WBR, Sergei >
