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authorSteven Rostedt <srostedt@redhat.com>2012-04-30 09:17:03 -0400
committerSteven Rostedt <rostedt@goodmis.org>2012-05-16 20:00:29 -0400
commitb732d439cb43336cd6d7e804ecb2c81193ef63b0 (patch)
tree8c89aec44ef3fbc6ff3e3afbf74ca5ded1354bc1 /kernel
parente4f5d5440bb860a3e8942ca8f7277a7f31798965 (diff)
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/Kconfig1
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
141config FUNCTION_TRACER 141config FUNCTION_TRACER
142 bool "Kernel Function Tracer" 142 bool "Kernel Function Tracer"
143 depends on HAVE_FUNCTION_TRACER 143 depends on HAVE_FUNCTION_TRACER
144 select FRAME_POINTER if !ARM_UNWIND && !PPC && !S390 && !MICROBLAZE
145 select KALLSYMS 144 select KALLSYMS
146 select GENERIC_TRACER 145 select GENERIC_TRACER
147 select CONTEXT_SWITCH_TRACER 146 select CONTEXT_SWITCH_TRACER