linux/scripts/Makefile.asm-headers
Arnd Bergmann fbb5c0606f kbuild: add syscall table generation to scripts/Makefile.asm-headers
There are 11 copies of arch/*/kernel/syscalls/Makefile that all implement
the same basic logic in a somewhat awkward way.

I tried out various ways of unifying the existing copies and ended up
with something that hooks into the logic for generating the redirections
to asm-generic headers. This gives a nicer syntax of being able to list
the generated files in $(syscall-y) inside of arch/*/include/asm/Kbuild
instead of both $(generated-y) in that place and also in another
Makefile.

The configuration for which syscall.tbl file to use and which ABIs to
enable is now done in arch/*/kernel/Makefile.syscalls. I have done
patches for all architectures and made sure that the new generic
rules implement a superset of all the architecture specific corner
cases.

ince the header file is not specific to asm-generic/*.h redirects
now, I ended up renaming the file to scripts/Makefile.asm-headers.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2024-07-10 14:23:38 +02:00

99 lines
3.2 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
# include/asm-generic contains a lot of files that are used
# verbatim by several architectures.
#
# This Makefile generates arch/$(SRCARCH)/include/generated/(uapi/)/asm
# headers from multiple sources:
# - a small wrapper to include the corresponding asm-generic/*.h
# is generated for each file listed as generic-y
# - uapi/asm/unistd_*.h files listed as syscalls-y are generated from
# syscall.tbl with the __NR_* macros
# - Corresponding asm/syscall_table_*.h are generated from the same input
PHONY := all
all:
src := $(srctree)/$(subst /generated,,$(obj))
syscall_abis_32 += common,32
syscall_abis_64 += common,64
syscalltbl := $(srctree)/scripts/syscall.tbl
syshdr-args := --emit-nr
# let architectures override $(syscall_abis_%) and $(syscalltbl)
-include $(srctree)/arch/$(SRCARCH)/kernel/Makefile.syscalls
include $(srctree)/scripts/Kbuild.include
-include $(kbuild-file)
syshdr := $(srctree)/scripts/syscallhdr.sh
systbl := $(srctree)/scripts/syscalltbl.sh
# $(generic)/Kbuild lists mandatory-y. Exclude um since it is a special case.
ifneq ($(SRCARCH),um)
include $(srctree)/$(generic)/Kbuild
endif
redundant := $(filter $(mandatory-y) $(generated-y), $(generic-y))
redundant += $(foreach f, $(generic-y), $(if $(wildcard $(src)/$(f)),$(f)))
redundant := $(sort $(redundant))
$(if $(redundant),\
$(warning redundant generic-y found in $(src)/Kbuild: $(redundant)))
# If arch does not implement mandatory headers, fallback to asm-generic ones.
mandatory-y := $(filter-out $(generated-y), $(mandatory-y))
generic-y += $(foreach f, $(mandatory-y), $(if $(wildcard $(src)/$(f)),,$(f)))
generic-y := $(addprefix $(obj)/, $(generic-y))
syscall-y := $(addprefix $(obj)/, $(syscall-y))
generated-y := $(addprefix $(obj)/, $(generated-y))
# Remove stale wrappers when the corresponding files are removed from generic-y
old-headers := $(wildcard $(obj)/*.h)
unwanted := $(filter-out $(generic-y) $(generated-y) $(syscall-y),$(old-headers))
quiet_cmd_wrap = WRAP $@
cmd_wrap = echo "\#include <asm-generic/$*.h>" > $@
quiet_cmd_remove = REMOVE $(unwanted)
cmd_remove = rm -f $(unwanted)
quiet_cmd_syshdr = SYSHDR $@
cmd_syshdr = $(CONFIG_SHELL) $(syshdr) \
$(if $(syshdr-args-$*),$(syshdr-args-$*),$(syshdr-args)) \
$(if $(syscall_compat),--prefix "compat$*_") \
--abis $(subst $(space),$(comma),$(strip $(syscall_abis_$*))) \
$< $@
quiet_cmd_systbl = SYSTBL $@
cmd_systbl = $(CONFIG_SHELL) $(systbl) \
$(if $(systbl-args-$*),$(systbl-args-$*),$(systbl-args)) \
--abis $(subst $(space),$(comma),$(strip $(syscall_abis_$*))) \
$< $@
all: $(generic-y) $(syscall-y)
$(if $(unwanted),$(call cmd,remove))
@:
$(obj)/%.h: $(srctree)/$(generic)/%.h
$(call cmd,wrap)
$(obj)/unistd_%.h: $(syscalltbl) $(syshdr) FORCE
$(call if_changed,syshdr)
$(obj)/unistd_compat_%.h: syscall_compat:=1
$(obj)/unistd_compat_%.h: $(syscalltbl) $(syshdr) FORCE
$(call if_changed,syshdr)
$(obj)/syscall_table_%.h: $(syscalltbl) $(systbl) FORCE
$(call if_changed,systbl)
# Create output directory. Skip it if at least one old header exists
# since we know the output directory already exists.
ifeq ($(old-headers),)
$(shell mkdir -p $(obj))
endif
FORCE:
.PHONY: $(PHONY)