# Make variables (CC, etc...)
AS = $(CROSS_COMPILE)as
LD = $(CROSS_COMPILE)ld
+LDFINAL = $(LD)
CC = $(CROSS_COMPILE)gcc
CPP = $(CC) -E
+ifdef CONFIG_LTO
+AR = $(CROSS_COMPILE)gcc-ar
+else
AR = $(CROSS_COMPILE)ar
+endif
NM = $(CROSS_COMPILE)nm
STRIP = $(CROSS_COMPILE)strip
OBJCOPY = $(CROSS_COMPILE)objcopy
export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
export ARCH SRCARCH CONFIG_SHELL HOSTCC HOSTCFLAGS CROSS_COMPILE AS LD CC
-export CPP AR NM STRIP OBJCOPY OBJDUMP
+export CPP AR NM STRIP OBJCOPY OBJDUMP LDFINAL
export MAKE AWK GENKSYMS INSTALLKERNEL PERL PYTHON UTS_MACHINE
export HOSTCXX HOSTCXXFLAGS LDFLAGS_MODULE CHECK CHECKFLAGS
export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
export KBUILD_ARFLAGS
+ifdef CONFIG_LTO
+# LTO gcc creates a lot of files in TMPDIR, and with /tmp as tmpfs
+# it's easy to drive the machine OOM. Use the object directory
+# instead.
+ifndef TMPDIR
+TMPDIR ?= $(objtree)
+export TMPDIR
+$(info setting TMPDIR=$(objtree) for LTO build)
+endif
+endif
+
# When compiling out-of-tree modules, put MODVERDIR in the module
# tree rather than in the kernel tree. The kernel tree might
# even be read-only.
include scripts/Makefile.kasan
include scripts/Makefile.extrawarn
+include scripts/Makefile.lto
# Add any arch overrides and user supplied CPPFLAGS, AFLAGS and CFLAGS as the
# last assignments
kselftest:
$(Q)$(MAKE) -C tools/testing/selftests run_tests
+kselftest-clean:
+ $(Q)$(MAKE) -C tools/testing/selftests clean
+
# ---------------------------------------------------------------------------
# Modules
@echo ' kselftest - Build and run kernel selftest (run as root)'
@echo ' Build, install, and boot kernel before'
@echo ' running kselftest on it'
+ @echo ' kselftest-clean - Remove all generated kselftest files'
@echo ''
@echo 'Kernel packaging:'
@$(MAKE) $(build)=$(package-dir) help