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authorLinus Torvalds <torvalds@linux-foundation.org>2021-09-03 15:33:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-09-03 15:33:47 -0700
commitb250e6d141ce4f0d0ada60e4b5db577050e5feb0 (patch)
tree682fd38e7efab61cc0963fa9e3137cdba2106111 /Makefile
parent4e71add02821bdd204dd29c35e66baecc9b6a235 (diff)
parentbc7cd2dd1f8e5889cc68b69984033ac5bef6ba61 (diff)
downloadlinux-b250e6d141ce4f0d0ada60e4b5db577050e5feb0.tar.bz2
Merge tag 'kbuild-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada: - Add -s option (strict mode) to merge_config.sh to make it fail when any symbol is redefined. - Show a warning if a different compiler is used for building external modules. - Infer --target from ARCH for CC=clang to let you cross-compile the kernel without CROSS_COMPILE. - Make the integrated assembler default (LLVM_IAS=1) for CC=clang. - Add <linux/stdarg.h> to the kernel source instead of borrowing <stdarg.h> from the compiler. - Add Nick Desaulniers as a Kbuild reviewer. - Drop stale cc-option tests. - Fix the combination of CONFIG_TRIM_UNUSED_KSYMS and CONFIG_LTO_CLANG to handle symbols in inline assembly. - Show a warning if 'FORCE' is missing for if_changed rules. - Various cleanups * tag 'kbuild-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (39 commits) kbuild: redo fake deps at include/ksym/*.h kbuild: clean up objtool_args slightly modpost: get the *.mod file path more simply checkkconfigsymbols.py: Fix the '--ignore' option kbuild: merge vmlinux_link() between ARCH=um and other architectures kbuild: do not remove 'linux' link in scripts/link-vmlinux.sh kbuild: merge vmlinux_link() between the ordinary link and Clang LTO kbuild: remove stale *.symversions kbuild: remove unused quiet_cmd_update_lto_symversions gen_compile_commands: extract compiler command from a series of commands x86: remove cc-option-yn test for -mtune= arc: replace cc-option-yn uses with cc-option s390: replace cc-option-yn uses with cc-option ia64: move core-y in arch/ia64/Makefile to arch/ia64/Kbuild sparc: move the install rule to arch/sparc/Makefile security: remove unneeded subdir-$(CONFIG_...) kbuild: sh: remove unused install script kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y kbuild: Switch to 'f' variants of integrated assembler flag kbuild: Shuffle blank line to improve comment meaning ...
Diffstat (limited to 'Makefile')
-rw-r--r--Makefile90
1 files changed, 49 insertions, 41 deletions
diff --git a/Makefile b/Makefile
index ec9e8a0fe298..6bc1c5b17a62 100644
--- a/Makefile
+++ b/Makefile
@@ -191,10 +191,9 @@ endif
ifneq ($(abs_srctree),$(abs_objtree))
# Look for make include files relative to root of kernel src
#
-# This does not become effective immediately because MAKEFLAGS is re-parsed
-# once after the Makefile is read. We need to invoke sub-make.
+# --included-dir is added for backward compatibility, but you should not rely on
+# it. Please add $(srctree)/ prefix to include Makefiles in the source tree.
MAKEFLAGS += --include-dir=$(abs_srctree)
-need-sub-make := 1
endif
ifneq ($(filter 3.%,$(MAKE_VERSION)),)
@@ -587,23 +586,10 @@ endif
# 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 = $(subst $(pound),,$(shell $(CC) --version 2>/dev/null | head -n 1))
+CC_VERSION_TEXT = $(subst $(pound),,$(shell LC_ALL=C $(CC) --version 2>/dev/null | head -n 1))
ifneq ($(findstring clang,$(CC_VERSION_TEXT)),)
-ifneq ($(CROSS_COMPILE),)
-CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%))
-endif
-ifeq ($(LLVM_IAS),1)
-CLANG_FLAGS += -integrated-as
-else
-CLANG_FLAGS += -no-integrated-as
-GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit))
-CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE))
-endif
-CLANG_FLAGS += -Werror=unknown-warning-option
-KBUILD_CFLAGS += $(CLANG_FLAGS)
-KBUILD_AFLAGS += $(CLANG_FLAGS)
-export CLANG_FLAGS
+include $(srctree)/scripts/Makefile.clang
endif
# Include this also for config targets because some architectures need
@@ -688,9 +674,10 @@ endif # KBUILD_EXTMOD
# 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,)
+CFLAGS_GCOV := -fprofile-arcs -ftest-coverage
+ifdef CONFIG_CC_IS_GCC
+CFLAGS_GCOV += -fno-tree-loop-im
+endif
export CFLAGS_GCOV
# The arch Makefiles can override CC_FLAGS_FTRACE. We may also append it later.
@@ -698,12 +685,14 @@ ifdef CONFIG_FUNCTION_TRACER
CC_FLAGS_FTRACE := -pg
endif
-RETPOLINE_CFLAGS_GCC := -mindirect-branch=thunk-extern -mindirect-branch-register
-RETPOLINE_VDSO_CFLAGS_GCC := -mindirect-branch=thunk-inline -mindirect-branch-register
-RETPOLINE_CFLAGS_CLANG := -mretpoline-external-thunk
-RETPOLINE_VDSO_CFLAGS_CLANG := -mretpoline
-RETPOLINE_CFLAGS := $(call cc-option,$(RETPOLINE_CFLAGS_GCC),$(call cc-option,$(RETPOLINE_CFLAGS_CLANG)))
-RETPOLINE_VDSO_CFLAGS := $(call cc-option,$(RETPOLINE_VDSO_CFLAGS_GCC),$(call cc-option,$(RETPOLINE_VDSO_CFLAGS_CLANG)))
+ifdef CONFIG_CC_IS_GCC
+RETPOLINE_CFLAGS := $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register)
+RETPOLINE_VDSO_CFLAGS := $(call cc-option,-mindirect-branch=thunk-inline -mindirect-branch-register)
+endif
+ifdef CONFIG_CC_IS_CLANG
+RETPOLINE_CFLAGS := -mretpoline-external-thunk
+RETPOLINE_VDSO_CFLAGS := -mretpoline
+endif
export RETPOLINE_CFLAGS
export RETPOLINE_VDSO_CFLAGS
@@ -756,7 +745,7 @@ include/config/auto.conf:
endif # may-sync-config
endif # need-config
-KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,)
+KBUILD_CFLAGS += -fno-delete-null-pointer-checks
KBUILD_CFLAGS += $(call cc-disable-warning,frame-address,)
KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation)
KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow)
@@ -771,17 +760,19 @@ KBUILD_CFLAGS += -Os
endif
# Tell gcc to never replace conditional load with a non-conditional one
+ifdef CONFIG_CC_IS_GCC
+# gcc-10 renamed --param=allow-store-data-races=0 to
+# -fno-allow-store-data-races.
KBUILD_CFLAGS += $(call cc-option,--param=allow-store-data-races=0)
KBUILD_CFLAGS += $(call cc-option,-fno-allow-store-data-races)
+endif
ifdef CONFIG_READABLE_ASM
# Disable optimizations that make assembler listings hard to read.
# reorder blocks reorders the control in the function
# ipa clone creates specialized cloned functions
# partial inlining inlines only parts of functions
-KBUILD_CFLAGS += $(call cc-option,-fno-reorder-blocks,) \
- $(call cc-option,-fno-ipa-cp-clone,) \
- $(call cc-option,-fno-partial-inlining)
+KBUILD_CFLAGS += -fno-reorder-blocks -fno-ipa-cp-clone -fno-partial-inlining
endif
ifneq ($(CONFIG_FRAME_WARN),0)
@@ -796,7 +787,7 @@ KBUILD_CFLAGS += $(stackp-flags-y)
ifdef CONFIG_CC_IS_CLANG
KBUILD_CPPFLAGS += -Qunused-arguments
-KBUILD_CFLAGS += -Wno-format-invalid-specifier
+# The kernel builds with '-std=gnu89' so use of GNU extensions is acceptable.
KBUILD_CFLAGS += -Wno-gnu
# CLANG uses a _MergedGlobals as optimization, but this breaks modpost, as the
# source of a reference will be _MergedGlobals and not on of the whitelisted names.
@@ -813,8 +804,8 @@ endif
# These warnings generated too much noise in a regular build.
# Use make W=1 to enable them (see scripts/Makefile.extrawarn)
KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable)
-
KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable)
+
ifdef CONFIG_FRAME_POINTER
KBUILD_CFLAGS += -fno-omit-frame-pointer -fno-optimize-sibling-calls
else
@@ -867,7 +858,7 @@ else
DEBUG_CFLAGS += -g
endif
-ifneq ($(LLVM_IAS),1)
+ifndef CONFIG_AS_IS_LLVM
KBUILD_AFLAGS += -Wa,-gdwarf-2
endif
@@ -878,8 +869,10 @@ DEBUG_CFLAGS += -gdwarf-$(dwarf-version-y)
endif
ifdef CONFIG_DEBUG_INFO_REDUCED
-DEBUG_CFLAGS += $(call cc-option, -femit-struct-debug-baseonly) \
- $(call cc-option,-fno-var-tracking)
+DEBUG_CFLAGS += -fno-var-tracking
+ifdef CONFIG_CC_IS_GCC
+DEBUG_CFLAGS += -femit-struct-debug-baseonly
+endif
endif
ifdef CONFIG_DEBUG_INFO_COMPRESSED
@@ -913,6 +906,7 @@ ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
endif
endif
ifdef CONFIG_HAVE_FENTRY
+ # s390-linux-gnu-gcc did not support -mfentry until gcc-9.
ifeq ($(call cc-option-yn, -mfentry),y)
CC_FLAGS_FTRACE += -mfentry
CC_FLAGS_USING += -DCC_USING_FENTRY
@@ -925,7 +919,7 @@ endif
# We trigger additional mismatches with less inlining
ifdef CONFIG_DEBUG_SECTION_MISMATCH
-KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions-called-once)
+KBUILD_CFLAGS += -fno-inline-functions-called-once
endif
ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
@@ -1004,14 +998,16 @@ KBUILD_CFLAGS += $(call cc-disable-warning, stringop-truncation)
# We'll want to enable this eventually, but it's not going away for 5.7 at least
KBUILD_CFLAGS += $(call cc-disable-warning, zero-length-bounds)
-KBUILD_CFLAGS += $(call cc-disable-warning, array-bounds)
+KBUILD_CFLAGS += -Wno-array-bounds
KBUILD_CFLAGS += $(call cc-disable-warning, stringop-overflow)
# Another good warning that we'll want to enable eventually
KBUILD_CFLAGS += $(call cc-disable-warning, restrict)
# Enabled with W=2, disabled by default as noisy
-KBUILD_CFLAGS += $(call cc-disable-warning, maybe-uninitialized)
+ifdef CONFIG_CC_IS_GCC
+KBUILD_CFLAGS += -Wno-maybe-uninitialized
+endif
# disable invalid "can't wrap" optimizations for signed / pointers
KBUILD_CFLAGS += -fno-strict-overflow
@@ -1020,7 +1016,9 @@ KBUILD_CFLAGS += -fno-strict-overflow
KBUILD_CFLAGS += -fno-stack-check
# conserve stack if available
-KBUILD_CFLAGS += $(call cc-option,-fconserve-stack)
+ifdef CONFIG_CC_IS_GCC
+KBUILD_CFLAGS += -fconserve-stack
+endif
# Prohibit date/time macros, which would make the build non-deterministic
KBUILD_CFLAGS += -Werror=date-time
@@ -1750,6 +1748,16 @@ clean-dirs := $(KBUILD_EXTMOD)
clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers $(KBUILD_EXTMOD)/modules.nsdeps \
$(KBUILD_EXTMOD)/compile_commands.json $(KBUILD_EXTMOD)/.thinlto-cache
+PHONY += prepare
+# now expand this into a simple variable to reduce the cost of shell evaluations
+prepare: CC_VERSION_TEXT := $(CC_VERSION_TEXT)
+prepare:
+ @if [ "$(CC_VERSION_TEXT)" != $(CONFIG_CC_VERSION_TEXT) ]; then \
+ echo >&2 "warning: the compiler differs from the one used to build the kernel"; \
+ echo >&2 " The kernel was built by: "$(CONFIG_CC_VERSION_TEXT); \
+ echo >&2 " You are using: $(CC_VERSION_TEXT)"; \
+ fi
+
PHONY += help
help:
@echo ' Building external modules.'
@@ -1761,7 +1769,7 @@ help:
@echo ''
# no-op for external module builds
-PHONY += prepare modules_prepare
+PHONY += modules_prepare
endif # KBUILD_EXTMOD