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| author | Steven Rostedt <srostedt@redhat.com> | 2012-04-30 15:17:03 +0200 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2012-05-17 02:00:29 +0200 |
| commit | b732d439cb43336cd6d7e804ecb2c81193ef63b0 (patch) | |
| tree | 8c89aec44ef3fbc6ff3e3afbf74ca5ded1354bc1 /kernel | |
| parent | ftrace/x86: Have x86 ftrace use the ftrace_modify_all_code() (diff) | |
| download | linux-b732d439cb43336cd6d7e804ecb2c81193ef63b0.tar.xz linux-b732d439cb43336cd6d7e804ecb2c81193ef63b0.zip | |
ftrace: Remove selecting FRAME_POINTER with FUNCTION_TRACER
The function tracer will enable the -pg option with gcc, which requires
that frame pointers. When FRAME_POINTER is defined in the kernel config
it adds the gcc option -fno-omit-frame-pointer which causes some problems
on some architectures. For those architectures, the FRAME_POINTER select
was not set.
When FUNCTION_TRACER was selected on these architectures that can not have
-fno-omit-frame-pointer, the -pg option is still set. But when
FRAME_POINTER is not selected, the kernel config would add the gcc option
-fomit-frame-pointer. Adding this option is incompatible with -pg
even on archs that do not need frame pointers with -pg.
The answer to this was to just not add either -fno-omit-frame-pointer
or -fomit-frame-pointer on these archs that want function tracing
but do not set FRAME_POINTER.
As it turns out, for archs that require frame pointers for function
tracing, the same can be used. If gcc requires frame pointers with
-pg, it will simply add it. The best thing to do is not select FRAME_POINTER
when function tracing is selected, and let gcc add it if needed.
Only add the -fno-omit-frame-pointer when something else selects
FRAME_POINTER, but do not add -fomit-frame-pointer if function tracing
is selected.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/Kconfig | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index a1d2849f2473..d81a1a532994 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -141,7 +141,6 @@ if FTRACE config FUNCTION_TRACER bool "Kernel Function Tracer" depends on HAVE_FUNCTION_TRACER - select FRAME_POINTER if !ARM_UNWIND && !PPC && !S390 && !MICROBLAZE select KALLSYMS select GENERIC_TRACER select CONTEXT_SWITCH_TRACER |