Hello!
Latest git kernel does not compile for me:
~/linux-2.6$ git desc
v5.3-11506-gf7c3bf8fa7e5
~/linux-2.6$ make
CALL scripts/checksyscalls.sh
<stdin>:1511:2: warning: #warning syscall clone3 not implemented [-Wcpp]
CALL scripts/atomic/check-atomics.sh
CHK include/generated/compile.h
CC arch/sparc/vdso/vdso32/vclock_gettime.o
unrecognized e_machine 18 arch/sparc/vdso/vdso32/vclock_gettime.o
arch/sparc/vdso/vdso32/vclock_gettime.o: failed
make[2]: *** [scripts/Makefile.build:266:
arch/sparc/vdso/vdso32/vclock_gettime.o] Error 1
make[2]: *** Deleting file 'arch/sparc/vdso/vdso32/vclock_gettime.o'
make[1]: *** [scripts/Makefile.build:509: arch/sparc/vdso] Error 2
make: *** [Makefile:1667: arch/sparc] Error
but I was able to compile successfully v5.3-10169-g574cc4539762
Not sure my bisect log is right, but here it is:
$ git bisect good
54b8ae66ae1a3454a7645d159a482c31cd89ab33 is the first bad commit
commit 54b8ae66ae1a3454a7645d159a482c31cd89ab33
Author: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Date: Fri Aug 30 13:34:01 2019 +0900
kbuild: change *FLAGS_<basetarget>.o to take the path relative to $(obj)
Kbuild provides per-file compiler flag addition/removal:
CFLAGS_<basetarget>.o
CFLAGS_REMOVE_<basetarget>.o
AFLAGS_<basetarget>.o
AFLAGS_REMOVE_<basetarget>.o
CPPFLAGS_<basetarget>.lds
HOSTCFLAGS_<basetarget>.o
HOSTCXXFLAGS_<basetarget>.o
The <basetarget> is the filename of the target with its directory and
suffix stripped.
This syntax comes into a trouble when two files with the same basename
appear in one Makefile, for example:
obj-y += foo.o
obj-y += dir/foo.o
CFLAGS_foo.o := <some-flags>
Here, the <some-flags> applies to both foo.o and dir/foo.o
The real world problem is:
scripts/kconfig/util.c
scripts/kconfig/lxdialog/util.c
Both files are compiled into scripts/kconfig/mconf, but only the
latter should be given with the ncurses flags.
It is more sensible to use the relative path to the Makefile, like this:
obj-y += foo.o
CFLAGS_foo.o := <some-flags>
obj-y += dir/foo.o
CFLAGS_dir/foo.o := <other-flags>
At first, I attempted to replace $(basetarget) with $*. The $* variable
is replaced with the stem ('%') part in a pattern rule. This works with
most of cases, but does not for explicit rules.
For example, arch/ia64/lib/Makefile reuses rule_as_o_S in its own
explicit rules, so $* will be empty, resulting in ignoring the per-file
AFLAGS.
I introduced a new variable, target-stem, which can be used also from
explicit rules.
Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Acked-by: Marc Zyngier <maz@xxxxxxxxxx>
arch/arm/kvm/Makefile | 5 +++--
arch/x86/entry/vdso/Makefile | 3 ++-
drivers/gpu/drm/amd/display/dc/calcs/Makefile | 6 +++---
drivers/gpu/drm/amd/display/dc/dcn20/Makefile | 2 +-
drivers/gpu/drm/amd/display/dc/dml/Makefile | 17 +++++++----------
drivers/gpu/drm/amd/display/dc/dsc/Makefile | 7 +++----
drivers/gpu/drm/i915/Makefile | 2 +-
scripts/Makefile.host | 22 +++++++++++-----------
scripts/Makefile.lib | 13 ++++++++-----
scripts/kconfig/Makefile | 8 ++++----
10 files changed, 43 insertions(+), 42 deletions(-)
mator@ttip:~/linux-2.6$
If someone wants to check how kernel compiles on sparc64, could use
gcc compile farm machine (gcc202) to try on.
Thanks.
