Currently empty .bss checks performed do not pay attention to "common
objects" in object files which end up in .bss section eventually.
The "size" tool is a part of binutils and since version 2.18 provides
"--common" command line option, which allows to account "common objects"
sizes in .bss section size. Utilize "size --common" to perform accurate
check that .bss section is unused. Besides that the size tool handles
object files without .bss section gracefully and doesn't require
additional objdump run.
The linux kernel requires binutils 2.20 since 4.13.
Kbuild exports OBJSIZE to reference the right size tool.
Link: http://lkml.kernel.org/r/patch-2.thread-2257a1.git-2257a1c53d4a.your-ad-here.call-01565088755-ext-5120@work.hours
Reported-and-tested-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
llvm skips an empty .bss section entirely, which makes
the check fail with an unexpected error:
/tmp/binutils-multi-test/bin/s390x-linux-gnu-objdump: section '.bss' mentioned in a -j option, but not found in any input file
error: arch/s390/boot/compressed/decompressor.o .bss section is not empty
../arch/s390/scripts/Makefile.chkbss:20: recipe for target 'arch/s390/boot/compressed/decompressor.o.chkbss' failed
Change the check so we first see if a .bss section exists
before trying to read its size.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
When I was refactoring cmd_ar_builtin in scripts/Makefile.build,
I noticed the build breakage of s390.
Some Makefiles of s390 add extra dependencies to built-in.a;
built-in.a depends on timestamp files *.o.chkbss, but $(AR) does
not want to include them into built-in.a.
Insert a phony target 'chkbss' in between so that $(AR) can take
$(filter-out $(PHONY), $^) as input.
While I was here, I refactored Makefile.chkbss a little bit.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Adding *.o.chkbss files to targets list makes sure that the kbuild is
aware of them and removes them during make clean.
Also remove *.o.chkbss file before an actual check, to avoid having
stale *.o.chkbss file left even if the check is failed.
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
"chkbss-target" could be now used to override default target .bss check
is bound to. Objects to be checked are only path extended when needed.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Introduce compile time check for files which should avoid using .bss
section, because of the following reasons:
- .bss section has not been zeroed yet,
- initrd has not been moved to a safe location and could be overlapping
with .bss section.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
