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| author | Steven Rostedt <srostedt@redhat.com> | 2011-02-09 13:27:22 -0500 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2012-08-23 11:25:29 -0400 |
| commit | 781d06248234e221edb560a18461d65808a8a942 (patch) | |
| tree | 99e4dcca5af9de75b5beb37a73d3250905613757 /kernel | |
| parent | a2546fae01124fb8063747439300fcf39bac033a (diff) | |
| download | lwn-781d06248234e221edb560a18461d65808a8a942.tar.gz lwn-781d06248234e221edb560a18461d65808a8a942.zip | |
ftrace: Do not test frame pointers if -mfentry is used
The function graph has a test to check if the frame pointer is
corrupted, which can happen with various options of gcc with mcount.
But this is not an issue with -mfentry as -mfentry does not need nor use
frame pointers for function graph tracing.
Link: http://lkml.kernel.org/r/20120807194059.773895870@goodmis.org
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/trace_functions_graph.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index ce27c8ba8d31..99b4378393d5 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -143,7 +143,7 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret, return; } -#ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST +#if defined(CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST) && !defined(CC_USING_FENTRY) /* * The arch may choose to record the frame pointer used * and check it here to make sure that it is what we expect it @@ -154,6 +154,9 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret, * * Currently, x86_32 with optimize for size (-Os) makes the latest * gcc do the above. + * + * Note, -mfentry does not use frame pointers, and this test + * is not needed if CC_USING_FENTRY is set. */ if (unlikely(current->ret_stack[index].fp != frame_pointer)) { ftrace_graph_stop(); |