linux/arch/um/kernel/Makefile
Masahiro Yamada b1992c3772 kbuild: use $(src) instead of $(srctree)/$(src) for source directory
Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for
checked-in source files. It is merely a convention without any functional
difference. In fact, $(obj) and $(src) are exactly the same, as defined
in scripts/Makefile.build:

    src := $(obj)

When the kernel is built in a separate output directory, $(src) does
not accurately reflect the source directory location. While Kbuild
resolves this discrepancy by specifying VPATH=$(srctree) to search for
source files, it does not cover all cases. For example, when adding a
header search path for local headers, -I$(srctree)/$(src) is typically
passed to the compiler.

This introduces inconsistency between upstream and downstream Makefiles
because $(src) is used instead of $(srctree)/$(src) for the latter.

To address this inconsistency, this commit changes the semantics of
$(src) so that it always points to the directory in the source tree.

Going forward, the variables used in Makefiles will have the following
meanings:

  $(obj)     - directory in the object tree
  $(src)     - directory in the source tree  (changed by this commit)
  $(objtree) - the top of the kernel object tree
  $(srctree) - the top of the kernel source tree

Consequently, $(srctree)/$(src) in upstream Makefiles need to be replaced
with $(src).

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2024-05-10 04:34:52 +09:00

66 lines
2.1 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
#
# Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux,intel}.com)
#
# Don't instrument UML-specific code; without this, we may crash when
# accessing the instrumentation buffer for the first time from the
# kernel.
KCOV_INSTRUMENT := n
CPPFLAGS_vmlinux.lds := -DSTART=$(LDS_START) \
-DELF_ARCH=$(LDS_ELF_ARCH) \
-DELF_FORMAT=$(LDS_ELF_FORMAT) \
$(LDS_EXTRA)
extra-y := vmlinux.lds
obj-y = config.o exec.o exitcode.o irq.o ksyms.o mem.o \
physmem.o process.o ptrace.o reboot.o sigio.o \
signal.o sysrq.o time.o tlb.o trap.o \
um_arch.o umid.o maccess.o kmsg_dump.o capflags.o skas/
obj-y += load_file.o
obj-$(CONFIG_BLK_DEV_INITRD) += initrd.o
obj-$(CONFIG_GPROF) += gprof_syms.o
obj-$(CONFIG_OF) += dtb.o
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-$(CONFIG_GENERIC_PCI_IOMAP) += ioport.o
USER_OBJS := config.o
include $(srctree)/arch/um/scripts/Makefile.rules
targets := config.c config.tmp capflags.c
# Be careful with the below Sed code - sed is pitfall-rich!
# We use sed to lower build requirements, for "embedded" builders for instance.
$(obj)/config.tmp: $(objtree)/.config FORCE
$(call if_changed,quote1)
quiet_cmd_quote1 = QUOTE $@
cmd_quote1 = sed -e 's/"/\\"/g' -e 's/^/"/' -e 's/$$/\\n",/' \
$< > $@
$(obj)/config.c: $(src)/config.c.in $(obj)/config.tmp FORCE
$(call if_changed,quote2)
quiet_cmd_mkcapflags = MKCAP $@
cmd_mkcapflags = $(CONFIG_SHELL) $(src)/../../x86/kernel/cpu/mkcapflags.sh $@ $^
cpufeature = $(src)/../../x86/include/asm/cpufeatures.h
vmxfeature = $(src)/../../x86/include/asm/vmxfeatures.h
$(obj)/capflags.c: $(cpufeature) $(vmxfeature) $(src)/../../x86/kernel/cpu/mkcapflags.sh FORCE
$(call if_changed,mkcapflags)
quiet_cmd_quote2 = QUOTE $@
cmd_quote2 = sed -e '/CONFIG/{' \
-e 's/"CONFIG"//' \
-e 'r $(obj)/config.tmp' \
-e 'a \' \
-e '""' \
-e '}' \
$< > $@