Merge branch 'kbuild/kbuild' into kbuild/for-next

[karo-tx-linux.git] / Makefile

diff --git a/Makefile b/Makefile
index 929d805b4f622eb42f1f0b50d110ef0ef487e6d3..6ed22b312b985519e463499138bf25f6c8df8249 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -352,9 +352,14 @@ include scripts/Kbuild.include
 # 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
@@ -416,7 +421,7 @@ KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(S
 
 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
 
@@ -427,6 +432,17 @@ export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
 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.
@@ -781,6 +797,7 @@ endif
 
 include scripts/Makefile.kasan
 include scripts/Makefile.extrawarn
+include scripts/Makefile.lto
 
 # Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
 KBUILD_CPPFLAGS += $(KCPPFLAGS)