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authorLinus Torvalds <torvalds@linux-foundation.org>2018-06-13 18:40:34 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-13 18:40:34 +0300
commitbe779f03d563981c65cc7417cc5e0dbbc5b89d30 (patch)
treece0638b1f449e2fe45419567ee287e2c97847836 /Makefile
parentd290ef9305ebaaac884ae0350bfc243dd01d354d (diff)
parent00979ce4fcc90d488c7f27f750097adc6b11bd07 (diff)
downloadlinux-be779f03d563981c65cc7417cc5e0dbbc5b89d30.tar.xz
Merge tag 'kbuild-v4.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull more Kbuild updates from Masahiro Yamada: - fix some bugs introduced by the recent Kconfig syntax extension - add some symbols about compiler information in Kconfig, such as CC_IS_GCC, CC_IS_CLANG, GCC_VERSION, etc. - test compiler capability for the stack protector in Kconfig, and clean-up Makefile - test compiler capability for GCC-plugins in Kconfig, and clean-up Makefile - allow to enable GCC-plugins for COMPILE_TEST - test compiler capability for KCOV in Kconfig and correct dependency - remove auto-detect mode of the GCOV format, which is now more nicely handled in Kconfig - test compiler capability for mprofile-kernel on PowerPC, and clean-up Makefile - misc cleanups * tag 'kbuild-v4.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: linux/linkage.h: replace VMLINUX_SYMBOL_STR() with __stringify() kconfig: fix localmodconfig sh: remove no-op macro VMLINUX_SYMBOL() powerpc/kbuild: move -mprofile-kernel check to Kconfig Documentation: kconfig: add recommended way to describe compiler support gcc-plugins: disable GCC_PLUGIN_STRUCTLEAK_BYREF_ALL for COMPILE_TEST gcc-plugins: allow to enable GCC_PLUGINS for COMPILE_TEST gcc-plugins: test plugin support in Kconfig and clean up Makefile gcc-plugins: move GCC version check for PowerPC to Kconfig kcov: test compiler capability in Kconfig and correct dependency gcov: remove CONFIG_GCOV_FORMAT_AUTODETECT arm64: move GCC version check for ARCH_SUPPORTS_INT128 to Kconfig kconfig: add CC_IS_CLANG and CLANG_VERSION kconfig: add CC_IS_GCC and GCC_VERSION stack-protector: test compiler capability in Kconfig and drop AUTO mode kbuild: fix endless syncconfig in case arch Makefile sets CROSS_COMPILE
Diffstat (limited to 'Makefile')
-rw-r--r--Makefile147
1 files changed, 36 insertions, 111 deletions
diff --git a/Makefile b/Makefile
index 019a5a020606..73f0bb2c7a98 100644
--- a/Makefile
+++ b/Makefile
@@ -442,8 +442,6 @@ export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
export KBUILD_ARFLAGS
-export CC_VERSION_TEXT := $(shell $(CC) --version | head -n 1)
-
# When compiling out-of-tree modules, put MODVERDIR in the module
# tree rather than in the kernel tree. The kernel tree might
# even be read-only.
@@ -514,6 +512,12 @@ ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/cc-can-link.sh $(CC)), y)
export CC_CAN_LINK
endif
+# The expansion should be delayed until arch/$(SRCARCH)/Makefile is included.
+# Some architectures define CROSS_COMPILE in arch/$(SRCARCH)/Makefile.
+# CC_VERSION_TEXT is referenced from Kconfig (so it needs export),
+# and from include/config/auto.conf.cmd to detect the compiler upgrade.
+CC_VERSION_TEXT = $(shell $(CC) --version | head -n 1)
+
ifeq ($(config-targets),1)
# ===========================================================================
# *config targets only - make sure prerequisites are updated, and descend
@@ -523,7 +527,7 @@ ifeq ($(config-targets),1)
# KBUILD_DEFCONFIG may point out an alternative default configuration
# used for 'make defconfig'
include arch/$(SRCARCH)/Makefile
-export KBUILD_DEFCONFIG KBUILD_KCONFIG
+export KBUILD_DEFCONFIG KBUILD_KCONFIG CC_VERSION_TEXT
config: scripts_basic outputmakefile FORCE
$(Q)$(MAKE) $(build)=scripts/kconfig $@
@@ -585,12 +589,32 @@ virt-y := virt/
endif # KBUILD_EXTMOD
ifeq ($(dot-config),1)
-# Read in config
-include include/config/auto.conf
+endif
+
+# The all: target is the default when no target is given on the
+# command line.
+# This allow a user to issue only 'make' to build a kernel including modules
+# Defaults to vmlinux, but the arch makefile usually adds further targets
+all: vmlinux
+
+CFLAGS_GCOV := -fprofile-arcs -ftest-coverage \
+ $(call cc-option,-fno-tree-loop-im) \
+ $(call cc-disable-warning,maybe-uninitialized,)
+export CFLAGS_GCOV
+# The arch Makefile can set ARCH_{CPP,A,C}FLAGS to override the default
+# values of the respective KBUILD_* variables
+ARCH_CPPFLAGS :=
+ARCH_AFLAGS :=
+ARCH_CFLAGS :=
+include arch/$(SRCARCH)/Makefile
+
+ifeq ($(dot-config),1)
ifeq ($(KBUILD_EXTMOD),)
-# Read in dependencies to all Kconfig* files, make sure to run
-# oldconfig if changes are detected.
+# Read in dependencies to all Kconfig* files, make sure to run syncconfig if
+# changes are detected. This should be included after arch/$(SRCARCH)/Makefile
+# because some architectures define CROSS_COMPILE there.
-include include/config/auto.conf.cmd
# To avoid any implicit rule to kick in, define an empty command
@@ -622,24 +646,6 @@ else
include/config/auto.conf: ;
endif # $(dot-config)
-# The all: target is the default when no target is given on the
-# command line.
-# This allow a user to issue only 'make' to build a kernel including modules
-# Defaults to vmlinux, but the arch makefile usually adds further targets
-all: vmlinux
-
-CFLAGS_GCOV := -fprofile-arcs -ftest-coverage \
- $(call cc-option,-fno-tree-loop-im) \
- $(call cc-disable-warning,maybe-uninitialized,)
-export CFLAGS_GCOV CFLAGS_KCOV
-
-# The arch Makefile can set ARCH_{CPP,A,C}FLAGS to override the default
-# values of the respective KBUILD_* variables
-ARCH_CPPFLAGS :=
-ARCH_AFLAGS :=
-ARCH_CFLAGS :=
-include arch/$(SRCARCH)/Makefile
-
KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,)
KBUILD_CFLAGS += $(call cc-disable-warning,frame-address,)
KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation)
@@ -680,55 +686,11 @@ ifneq ($(CONFIG_FRAME_WARN),0)
KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN})
endif
-# This selects the stack protector compiler flag. Testing it is delayed
-# until after .config has been reprocessed, in the prepare-compiler-check
-# target.
-ifdef CONFIG_CC_STACKPROTECTOR_AUTO
- stackp-flag := $(call cc-option,-fstack-protector-strong,$(call cc-option,-fstack-protector))
- stackp-name := AUTO
-else
-ifdef CONFIG_CC_STACKPROTECTOR_REGULAR
- stackp-flag := -fstack-protector
- stackp-name := REGULAR
-else
-ifdef CONFIG_CC_STACKPROTECTOR_STRONG
- stackp-flag := -fstack-protector-strong
- stackp-name := STRONG
-else
- # If either there is no stack protector for this architecture or
- # CONFIG_CC_STACKPROTECTOR_NONE is selected, we're done, and $(stackp-name)
- # is empty, skipping all remaining stack protector tests.
- #
- # Force off for distro compilers that enable stack protector by default.
- KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector)
-endif
-endif
-endif
-# Find arch-specific stack protector compiler sanity-checking script.
-ifdef stackp-name
-ifneq ($(stackp-flag),)
- stackp-path := $(srctree)/scripts/gcc-$(SRCARCH)_$(BITS)-has-stack-protector.sh
- stackp-check := $(wildcard $(stackp-path))
- # If the wildcard test matches a test script, run it to check functionality.
- ifdef stackp-check
- ifneq ($(shell $(CONFIG_SHELL) $(stackp-check) $(CC) $(KBUILD_CPPFLAGS) $(biarch)),y)
- stackp-broken := y
- endif
- endif
- ifndef stackp-broken
- # If the stack protector is functional, enable code that depends on it.
- KBUILD_CPPFLAGS += -DCONFIG_CC_STACKPROTECTOR
- # Either we've already detected the flag (for AUTO) or we'll fail the
- # build in the prepare-compiler-check rule (for specific flag).
- KBUILD_CFLAGS += $(stackp-flag)
- else
- # We have to make sure stack protector is unconditionally disabled if
- # the compiler is broken (in case we're going to continue the build in
- # AUTO mode).
- KBUILD_CFLAGS += $(call cc-option, -fno-stack-protector)
- endif
-endif
-endif
+stackp-flags-$(CONFIG_CC_HAS_STACKPROTECTOR_NONE) := -fno-stack-protector
+stackp-flags-$(CONFIG_CC_STACKPROTECTOR) := -fstack-protector
+stackp-flags-$(CONFIG_CC_STACKPROTECTOR_STRONG) := -fstack-protector-strong
+
+KBUILD_CFLAGS += $(stackp-flags-y)
ifeq ($(cc-name),clang)
KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,)
@@ -1112,7 +1074,7 @@ endif
# prepare2 creates a makefile if using a separate output directory.
# From this point forward, .config has been reprocessed, so any rules
# that need to depend on updated CONFIG_* values can be checked here.
-prepare2: prepare3 prepare-compiler-check outputmakefile asm-generic
+prepare2: prepare3 outputmakefile asm-generic
prepare1: prepare2 $(version_h) $(autoksyms_h) include/generated/utsrelease.h \
include/config/auto.conf
@@ -1138,43 +1100,6 @@ uapi-asm-generic:
PHONY += prepare-objtool
prepare-objtool: $(objtool_target)
-# Check for CONFIG flags that require compiler support. Abort the build
-# after .config has been processed, but before the kernel build starts.
-#
-# For security-sensitive CONFIG options, we don't want to fallback and/or
-# silently change which compiler flags will be used, since that leads to
-# producing kernels with different security feature characteristics
-# depending on the compiler used. (For example, "But I selected
-# CC_STACKPROTECTOR_STRONG! Why did it build with _REGULAR?!")
-PHONY += prepare-compiler-check
-prepare-compiler-check: FORCE
-# Make sure compiler supports requested stack protector flag.
-ifdef stackp-name
- # Warn about CONFIG_CC_STACKPROTECTOR_AUTO having found no option.
- ifeq ($(stackp-flag),)
- @echo CONFIG_CC_STACKPROTECTOR_$(stackp-name): \
- Compiler does not support any known stack-protector >&2
- else
- # Fail if specifically requested stack protector is missing.
- ifeq ($(call cc-option, $(stackp-flag)),)
- @echo Cannot use CONFIG_CC_STACKPROTECTOR_$(stackp-name): \
- $(stackp-flag) not supported by compiler >&2 && exit 1
- endif
- endif
-endif
-# Make sure compiler does not have buggy stack-protector support. If a
-# specific stack-protector was requested, fail the build, otherwise warn.
-ifdef stackp-broken
- ifeq ($(stackp-name),AUTO)
- @echo CONFIG_CC_STACKPROTECTOR_$(stackp-name): \
- $(stackp-flag) available but compiler is broken: disabling >&2
- else
- @echo Cannot use CONFIG_CC_STACKPROTECTOR_$(stackp-name): \
- $(stackp-flag) available but compiler is broken >&2 && exit 1
- endif
-endif
- @:
-
# Generate some files
# ---------------------------------------------------------------------------