linux_dsm_epyc7002/arch
Masahiro Yamada 15d5761ad3 kbuild: introduce ccflags-remove-y and asflags-remove-y
CFLAGS_REMOVE_<file>.o filters out flags when compiling a particular
object, but there is no convenient way to do that for every object in
a directory.

Add ccflags-remove-y and asflags-remove-y to make it easily.

Use ccflags-remove-y to clean up some Makefiles.

The add/remove order works as follows:

 [1] KBUILD_CFLAGS specifies compiler flags used globally

 [2] ccflags-y adds compiler flags for all objects in the
     current Makefile

 [3] ccflags-remove-y removes compiler flags for all objects in the
     current Makefile (New feature)

 [4] CFLAGS_<file> adds compiler flags per file.

 [5] CFLAGS_REMOVE_<file> removes compiler flags per file.

Having [3] before [4] allows us to remove flags from most (but not all)
objects in the current Makefile.

For example, kernel/trace/Makefile removes $(CC_FLAGS_FTRACE)
from all objects in the directory, then adds it back to
trace_selftest_dynamic.o and CFLAGS_trace_kprobe_selftest.o

The same applies to lib/livepatch/Makefile.

Please note ccflags-remove-y has no effect to the sub-directories.
In contrast, the previous notation got rid of compiler flags also from
all the sub-directories.

The following are not affected because they have no sub-directories:

  arch/arm/boot/compressed/
  arch/powerpc/xmon/
  arch/sh/
  kernel/trace/

However, lib/ has several sub-directories.

To keep the behavior, I added ccflags-remove-y to all Makefiles
in subdirectories of lib/, except the following:

  lib/vdso/Makefile        - Kbuild does not descend into this Makefile
  lib/raid/test/Makefile   - This is not used for the kernel build

I think commit 2464a609de ("ftrace: do not trace library functions")
excluded too much. In the next commit, I will remove ccflags-remove-y
from the sub-directories of lib/.

Suggested-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Acked-by: Brendan Higgins <brendanhiggins@google.com> (KUnit)
Tested-by: Anders Roxell <anders.roxell@linaro.org>
2020-08-10 01:32:59 +09:00
..
alpha Kbuild updates for v5.8 (2nd) 2020-06-13 13:29:16 -07:00
arc treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
arm kbuild: introduce ccflags-remove-y and asflags-remove-y 2020-08-10 01:32:59 +09:00
arm64 arm64 fixes for -rc4 2020-07-04 14:43:26 -07:00
c6x This time around we have 4 lines of diff in the core framework, removing a 2020-06-10 11:42:19 -07:00
csky maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault 2020-06-17 10:57:41 -07:00
h8300 This time around we have 4 lines of diff in the core framework, removing a 2020-06-10 11:42:19 -07:00
hexagon treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
ia64 Merge branch 'hch' (maccess patches from Christoph Hellwig) 2020-06-18 12:35:51 -07:00
m68k m68k: mm: fix node memblock init 2020-06-29 23:58:05 +10:00
microblaze mmap locking API: convert mmap_sem comments 2020-06-09 09:39:14 -07:00
mips kbuild: remove cc-option test of -fno-stack-protector 2020-07-07 11:13:10 +09:00
nds32 maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault 2020-06-17 10:57:41 -07:00
nios2 nios2 update for v5.8-rc1 2020-06-12 11:55:11 -07:00
openrisc openrisc: fix boot oops when DEBUG_VM is enabled 2020-06-26 00:27:36 -07:00
parisc maccess: make get_kernel_nofault() check for minimal type compatibility 2020-06-18 12:10:37 -07:00
powerpc kbuild: introduce ccflags-remove-y and asflags-remove-y 2020-08-10 01:32:59 +09:00
riscv riscv: Fixup __vdso_gettimeofday broke dynamic ftrace 2020-06-25 15:38:39 -07:00
s390 kbuild: remove cc-option test of -ffreestanding 2020-07-07 11:13:10 +09:00
sh kbuild: introduce ccflags-remove-y and asflags-remove-y 2020-08-10 01:32:59 +09:00
sparc kbuild: remove cc-option test of -fno-stack-protector 2020-07-07 11:13:10 +09:00
um kbuild: remove cc-option test of -fno-stack-protector 2020-07-07 11:13:10 +09:00
unicore32 This time around we have 4 lines of diff in the core framework, removing a 2020-06-10 11:42:19 -07:00
x86 kbuild: remove cc-option test of -ffreestanding 2020-07-07 11:13:10 +09:00
xtensa kbuild: do not export LDFLAGS_vmlinux 2020-08-10 01:32:58 +09:00
.gitignore
Kconfig kbuild: remove cc-option test of -fno-stack-protector 2020-07-07 11:13:10 +09:00