linux/scripts/Makefile.asm-headers
Masahiro Yamada 49208b6758 kbuild: fix rebuild of generic syscall headers
Commit fbb5c0606f ("kbuild: add syscall table generation to
scripts/Makefile.asm-headers") started to generate syscall headers
for architectures using generic syscalls.

However, these headers are always rebuilt using GNU Make 4.4.1 or newer.

When using GNU Make 4.4 or older, these headers are not rebuilt when the
command to generate them is changed, despite the use of the if_changed
macro.

scripts/Makefile.asm-headers now uses FORCE, but it is not marked as
.PHONY. To handle the command line change correctly, .*.cmd files must
be included.

Fixes: fbb5c0606f ("kbuild: add syscall table generation to scripts/Makefile.asm-headers")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Closes: https://lore.kernel.org/lkml/CAHk-=wibB7SvXnUftBgAt+4-3vEKRpvEgBeDEH=i=j2GvDitoA@mail.gmail.com/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-07-18 10:01:55 -07:00

107 lines
3.4 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)
targets := $(syscall-y)
# Create output directory. Skip it if at least one old header exists
# since we know the output directory already exists.
ifeq ($(old-headers),)
$(shell mkdir -p $(obj))
endif
PHONY += FORCE
FORCE:
existing-targets := $(wildcard $(sort $(targets)))
-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
.PHONY: $(PHONY)