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authorVasily Gorbik <gor@linux.ibm.com>2018-08-06 15:17:46 +0200
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2018-08-15 22:38:38 -0400
commit2f4df0017baedd535254d987c6b10f855f1fb11f (patch)
treec035a8d2357ee4c54b584a3ba4153d4673fa057f /Makefile
parent07d0408120216b60625c9a5b8012d1c3a907984d (diff)
downloadlwn-2f4df0017baedd535254d987c6b10f855f1fb11f.tar.gz
lwn-2f4df0017baedd535254d987c6b10f855f1fb11f.zip
tracing: Add -mcount-nop option support
-mcount-nop gcc option generates the calls to the profiling functions as nops which allows to avoid patching mcount jump with NOP instructions initially. -mcount-nop gcc option will be activated if platform selects HAVE_NOP_MCOUNT and gcc actually supports it. In addition to that CC_USING_NOP_MCOUNT is defined and could be used by architectures to adapt ftrace patching behavior. Link: http://lkml.kernel.org/r/patch-3.thread-aa7b8d.git-e02ed2dc082b.your-ad-here.call-01533557518-ext-9465@work.hours Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'Makefile')
-rw-r--r--Makefile6
1 files changed, 6 insertions, 0 deletions
diff --git a/Makefile b/Makefile
index 2c92ebf59a34..c5b0cd7f3c2a 100644
--- a/Makefile
+++ b/Makefile
@@ -749,6 +749,12 @@ ifdef CONFIG_FTRACE_MCOUNT_RECORD
CC_FLAGS_FTRACE += -mrecord-mcount
export CC_USING_RECORD_MCOUNT := 1
endif
+ ifdef CONFIG_HAVE_NOP_MCOUNT
+ ifeq ($(call cc-option-yn, -mnop-mcount),y)
+ CC_FLAGS_FTRACE += -mnop-mcount
+ CC_FLAGS_USING += -DCC_USING_NOP_MCOUNT
+ endif
+ endif
endif
ifdef CONFIG_HAVE_FENTRY
ifeq ($(call cc-option-yn, -mfentry),y)