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kbuild/recordmcount: Add RECORDMCOUNT_WARN to warn about mcount callers

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When mcount is called in a section that ftrace will not modify it into
a nop, we want to warn about this. But not warn about this always. Now
if the user builds the kernel with the option RECORDMCOUNT_WARN=1 then
the build will warn about mcount callers that are ignored and will just
waste execution time.

Acked-by: Michal Marek <mmarek@suse.cz>
Cc: linux-kbuild@vger.kernel.org
Link: http://lkml.kernel.org/r/20110421023738.714956282@goodmis.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt 2011-04-12 18:59:10 -04:00 committed by Steven Rostedt
parent 06fd6f6301
commit a3a8350ab2
2 changed files with 5 additions and 1 deletions
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1
Makefile
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@ -1268,6 +1268,7 @@ help:
@echo ' make C=1 [targets] Check all c source with $$CHECK (sparse by default)' @echo ' make C=1 [targets] Check all c source with $$CHECK (sparse by default)'
@echo ' make C=2 [targets] Force check of all c source with $$CHECK' @echo ' make C=2 [targets] Force check of all c source with $$CHECK'
@echo ' make W=1 [targets] Enable extra gcc checks' @echo ' make W=1 [targets] Enable extra gcc checks'
@echo ' make RECORDMCOUNT_WARN=1 [targets] Warn about ignored mcount sections'
@echo '' @echo ''
@echo 'Execute "make" or "make all" to build all targets marked with [*] ' @echo 'Execute "make" or "make all" to build all targets marked with [*] '
@echo 'For further info see the ./README file' @echo 'For further info see the ./README file'

5
scripts/Makefile.build
View File

@ -244,13 +244,16 @@ endif
ifdef CONFIG_FTRACE_MCOUNT_RECORD ifdef CONFIG_FTRACE_MCOUNT_RECORD
ifdef BUILD_C_RECORDMCOUNT ifdef BUILD_C_RECORDMCOUNT
ifeq ("$(origin RECORDMCOUNT_WARN)", "command line")
RECORDMCOUNT_FLAGS = -w
endif
# Due to recursion, we must skip empty.o. # Due to recursion, we must skip empty.o.
# The empty.o file is created in the make process in order to determine # The empty.o file is created in the make process in order to determine
# the target endianness and word size. It is made before all other C # the target endianness and word size. It is made before all other C
# files, including recordmcount. # files, including recordmcount.
sub_cmd_record_mcount = \ sub_cmd_record_mcount = \
if [ $(@) != "scripts/mod/empty.o" ]; then \ if [ $(@) != "scripts/mod/empty.o" ]; then \
$(objtree)/scripts/recordmcount "$(@)"; \ $(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)"; \
fi; fi;
recordmcount_source := $(srctree)/scripts/recordmcount.c \ recordmcount_source := $(srctree)/scripts/recordmcount.c \
$(srctree)/scripts/recordmcount.h $(srctree)/scripts/recordmcount.h