@@ -616,6 +616,11 @@ CFLAGS_GCOV := -fprofile-arcs -ftest-coverage \
$(call cc-disable-warning,maybe-uninitialized,)
export CFLAGS_GCOV
+# The arch Makefiles can override CC_FLAGS_FTRACE. We may also append it later.
+ifdef CONFIG_FUNCTION_TRACER
+ CC_FLAGS_FTRACE := -pg
+endif
+
# The arch Makefile can set ARCH_{CPP,A,C}FLAGS to override the default
# values of the respective KBUILD_* variables
ARCH_CPPFLAGS :=
@@ -755,9 +760,6 @@ KBUILD_CFLAGS += $(call cc-option, -femit-struct-debug-baseonly) \
endif
ifdef CONFIG_FUNCTION_TRACER
-ifndef CC_FLAGS_FTRACE
-CC_FLAGS_FTRACE := -pg
-endif
ifdef CONFIG_FTRACE_MCOUNT_RECORD
# gcc 5 supports generating the mcount tables directly
ifeq ($(call cc-option-yn,-mrecord-mcount),y)
Linus, This fixes an issue with the build system caused by a change that modifies CC_FLAGS_FTRACE. The issue is that it breaks the dependencies and causes "make targz-pkg" to rebuild the entire world. Please pull the latest trace-v4.19-rc3 tree, which can be found at: git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git trace-v4.19-rc3 Tag SHA1: f1da41d2d7997791e929e804b646dffd0765e677 Head SHA1: b1f4ff74fcb0e82664e8633cc225c2ad4234878a Paulo Zanoni (1): tracing/Makefile: Fix handling redefinition of CC_FLAGS_FTRACE ---- Makefile | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --------------------------- commit b1f4ff74fcb0e82664e8633cc225c2ad4234878a Author: Paulo Zanoni <paulo.r.zanoni@intel.com> Date: Mon Sep 10 10:59:56 2018 -0700 tracing/Makefile: Fix handling redefinition of CC_FLAGS_FTRACE As a Kernel developer, I make heavy use of "make targz-pkg" in order to locally compile and remotely install my development Kernels. The nice feature I rely on is that after a normal "make", "make targz-pkg" only generates the tarball without having to recompile everything. That was true until commit f28bc3c32c05 ("tracing: Handle CC_FLAGS_FTRACE more accurately"). After it, running "make targz-pkg" after "make" will recompile the whole Kernel tree, making my development workflow much slower. The Kernel is choosing to recompile everything because it claims the command line has changed. A diff of the .cmd files show a repeated -mfentry in one of the files. That is because "make targz-pkg" calls "make modules_install" and the environment is already populated with the exported variables, CC_FLAGS_FTRACE being one of them. Then, -mfentry gets duplicated because it is not protected behind an ifndef block, like -pg. To complicate the problem a little bit more, architectures can define their own version CC_FLAGS_FTRACE, so our code not only has to consider recursive Makefiles, but also architecture overrides. So in this patch we move CC_FLAGS_FTRACE up and unconditionally define it to -pg. Then we let the architecture Makefiles possibly override it, and finally append the extra options later. This ensures the variable is always fully redefined at each invocation so recursive Makefiles don't keep appending, and hopefully it maintains the intended behavior on how architectures can override the defaults.. Thanks Steven Rostedt and Vasily Gorbik for the help on this regression. Cc: Michal Marek <michal.lkml@markovi.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: linux-kbuild@vger.kernel.org Fixes: commit f28bc3c32c05 ("tracing: Handle CC_FLAGS_FTRACE more accurately") Acked-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>