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MIPS, Tracing: Fix set_graph_function of function graph tracer

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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 expected.

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@163.com>
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Sergei Shtylyov <sshtylyov@mvista.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2017/
Signed-off-by: Ralf Baechle <ralf@duck.linux-mips.net>
This commit is contained in:
Wu Zhangjin 2011-01-22 02:01:53 +08:00 committed by Ralf Baechle
parent 7f21a60968
commit b9f07eb2f2
1 changed files with 9 additions and 2 deletions
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11
arch/mips/kernel/ftrace.c
View file

@ -257,7 +257,7 @@ void prepare_ftrace_return(unsigned long *parent_ra_addr, unsigned long self_ra,
struct ftrace_graph_ent trace;
unsigned long return_hooker = (unsigned long)
&return_to_handler;
int faulted;
int faulted, insns;
if (unlikely(atomic_read(&current->tracing_graph_pause)))
return;
@ -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;
trace.func = self_ra - (MCOUNT_INSN_SIZE * insns);
/* Only trace if the calling function expects to */
if (!ftrace_graph_entry(&trace)) {