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| author | Steven Rostedt (VMware) | 2017-03-23 15:33:52 +0100 |
|---|---|---|
| committer | Thomas Gleixner | 2017-03-24 10:14:07 +0100 |
| commit | 644e0e8dc76b919976c44d3929164d42cbe656bc (patch) | |
| tree | e11a16a3e85b3138629648d44c3dc08d6bfc18df /arch/x86/Kconfig | |
| parent | x86/ftrace: Clean up ftrace_regs_caller (diff) | |
| download | kernel-qcow2-linux-644e0e8dc76b919976c44d3929164d42cbe656bc.tar.gz kernel-qcow2-linux-644e0e8dc76b919976c44d3929164d42cbe656bc.tar.xz kernel-qcow2-linux-644e0e8dc76b919976c44d3929164d42cbe656bc.zip | |
x86/ftrace: Add -mfentry support to x86_32 with DYNAMIC_FTRACE set
x86_64 has had fentry support for some time. I did not add support to x86_32
as I was unsure if it will be used much in the future. It is still very much
used, and there's issues with function graph tracing with gcc playing around
with the mcount frames, causing function graph to panic. The fentry code
does not have this issue, and is able to cope as there is no frame to mess
up.
Note, this only adds support for fentry when DYNAMIC_FTRACE is set. There's
really no reason to not have that set, because the performance of the
machine drops significantly when it's not enabled.
Keep !DYNAMIC_FTRACE around to test it off, as there's still some archs
that have FTRACE but not DYNAMIC_FTRACE.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20170323143446.052202377@goodmis.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/Kconfig')
| -rw-r--r-- | arch/x86/Kconfig | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index cc98d5a294ee..8c17146427ca 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -127,7 +127,7 @@ config X86 select HAVE_EBPF_JIT if X86_64 select HAVE_EFFICIENT_UNALIGNED_ACCESS select HAVE_EXIT_THREAD - select HAVE_FENTRY if X86_64 + select HAVE_FENTRY if X86_64 || DYNAMIC_FTRACE select HAVE_FTRACE_MCOUNT_RECORD select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER |