Merge tag 'kbuild-v5.7-2' of git://git.kernel.org/pub/scm/linux/kerne…

…l/git/masahiroy/linux-kbuild

Pull more Kbuild updates from Masahiro Yamada:

 - raise minimum supported binutils version to 2.23

 - remove old CONFIG_AS_* macros that we know binutils >= 2.23 supports

 - move remaining CONFIG_AS_* tests to Kconfig from Makefile

 - enable -Wtautological-compare warnings to catch more issues

 - do not support GCC plugins for GCC <= 4.7

 - fix various breakages of 'make xconfig'

 - include the linker version used for linking the kernel into
   LINUX_COMPILER, which is used for the banner, and also exposed to
   /proc/version

 - link lib-y objects to vmlinux forcibly when CONFIG_MODULES=y, which
   allows us to remove the lib-ksyms.o workaround, and to solve the last
   known issue of the LLVM linker

 - add dummy tools in scripts/dummy-tools/ to enable all compiler tests
   in Kconfig, which will be useful for distro maintainers

 - support the single switch, LLVM=1 to use Clang and all LLVM utilities
   instead of GCC and Binutils.

 - support LLVM_IAS=1 to enable the integrated assembler, which is still
   experimental

* tag 'kbuild-v5.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (36 commits)
  kbuild: fix comment about missing include guard detection
  kbuild: support LLVM=1 to switch the default tools to Clang/LLVM
  kbuild: replace AS=clang with LLVM_IAS=1
  kbuild: add dummy toolchains to enable all cc-option etc. in Kconfig
  kbuild: link lib-y objects to vmlinux forcibly when CONFIG_MODULES=y
  MIPS: fw: arc: add __weak to prom_meminit and prom_free_prom_memory
  kbuild: remove -I$(srctree)/tools/include from scripts/Makefile
  kbuild: do not pass $(KBUILD_CFLAGS) to scripts/mkcompile_h
  Documentation/llvm: fix the name of llvm-size
  kbuild: mkcompile_h: Include $LD version in /proc/version
  kconfig: qconf: Fix a few alignment issues
  kconfig: qconf: remove some old bogus TODOs
  kconfig: qconf: fix support for the split view mode
  kconfig: qconf: fix the content of the main widget
  kconfig: qconf: Change title for the item window
  kconfig: qconf: clean deprecated warnings
  gcc-plugins: drop support for GCC <= 4.7
  kbuild: Enable -Wtautological-compare
  x86: update AS_* macros to binutils >=2.23, supporting ADX and AVX2
  crypto: x86 - clean up poly1305-x86_64-cryptogams.S by 'make clean'
  ...

Documentation/kbuild/kbuild.rst

@@ -262,3 +262,8 @@ KBUILD_BUILD_USER, KBUILD_BUILD_HOST
 These two variables allow to override the user@host string displayed during
 boot and in /proc/version. The default value is the output of the commands
 whoami and host, respectively.
+
+LLVM
+----
+If this variable is set to 1, Kbuild will use Clang and LLVM utilities instead
+of GCC and GNU binutils to build the kernel.

Documentation/kbuild/llvm.rst

@@ -47,14 +47,21 @@ example:
 LLVM Utilities
 --------------
 
-LLVM has substitutes for GNU binutils utilities. These can be invoked as
-additional parameters to `make`.
+LLVM has substitutes for GNU binutils utilities. Kbuild supports `LLVM=1`
+to enable them.
 
-	make CC=clang AS=clang LD=ld.lld AR=llvm-ar NM=llvm-nm STRIP=llvm-strip \\
-	  OBJCOPY=llvm-objcopy OBJDUMP=llvm-objdump OBJSIZE=llvm-objsize \\
+	make LLVM=1
+
+They can be enabled individually. The full list of the parameters:
+
+	make CC=clang LD=ld.lld AR=llvm-ar NM=llvm-nm STRIP=llvm-strip \\
+	  OBJCOPY=llvm-objcopy OBJDUMP=llvm-objdump OBJSIZE=llvm-size \\
 	  READELF=llvm-readelf HOSTCC=clang HOSTCXX=clang++ HOSTAR=llvm-ar \\
 	  HOSTLD=ld.lld
 
+Currently, the integrated assembler is disabled by default. You can pass
+`LLVM_IAS=1` to enable it.
+
 Getting Help
 ------------
 

Documentation/process/changes.rst

@@ -31,7 +31,7 @@ you probably needn't concern yourself with pcmciautils.
 ====================== ===============  ========================================
 GNU C                  4.6              gcc --version
 GNU make               3.81             make --version
-binutils               2.21             ld -v
+binutils               2.23             ld -v
 flex                   2.5.35           flex --version
 bison                  2.0              bison --version
 util-linux             2.10o            fdformat --version
@@ -76,7 +76,7 @@ You will need GNU make 3.81 or later to build the kernel.
 Binutils
 --------
 
-Binutils 2.21 or newer is needed to build the kernel.
+Binutils 2.23 or newer is needed to build the kernel.
 
 pkg-config
 ----------

Makefile

@@ -399,8 +399,13 @@ HOST_LFS_CFLAGS := $(shell getconf LFS_CFLAGS 2>/dev/null)
 HOST_LFS_LDFLAGS := $(shell getconf LFS_LDFLAGS 2>/dev/null)
 HOST_LFS_LIBS := $(shell getconf LFS_LIBS 2>/dev/null)
 
-HOSTCC       = gcc
-HOSTCXX      = g++
+ifneq ($(LLVM),)
+HOSTCC	= clang
+HOSTCXX	= clang++
+else
+HOSTCC	= gcc
+HOSTCXX	= g++
+endif
 KBUILD_HOSTCFLAGS   := -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 \
 		-fomit-frame-pointer -std=gnu89 $(HOST_LFS_CFLAGS) \
 		$(HOSTCFLAGS)
@@ -409,16 +414,28 @@ KBUILD_HOSTLDFLAGS  := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS)
 KBUILD_HOSTLDLIBS   := $(HOST_LFS_LIBS) $(HOSTLDLIBS)
 
 # Make variables (CC, etc...)
-LD		= $(CROSS_COMPILE)ld
-CC		= $(CROSS_COMPILE)gcc
 CPP		= $(CC) -E
+ifneq ($(LLVM),)
+CC		= clang
+LD		= ld.lld
+AR		= llvm-ar
+NM		= llvm-nm
+OBJCOPY		= llvm-objcopy
+OBJDUMP		= llvm-objdump
+READELF		= llvm-readelf
+OBJSIZE		= llvm-size
+STRIP		= llvm-strip
+else
+CC		= $(CROSS_COMPILE)gcc
+LD		= $(CROSS_COMPILE)ld
 AR		= $(CROSS_COMPILE)ar
 NM		= $(CROSS_COMPILE)nm
-STRIP		= $(CROSS_COMPILE)strip
 OBJCOPY		= $(CROSS_COMPILE)objcopy
 OBJDUMP		= $(CROSS_COMPILE)objdump
-OBJSIZE		= $(CROSS_COMPILE)size
 READELF		= $(CROSS_COMPILE)readelf
+OBJSIZE		= $(CROSS_COMPILE)size
+STRIP		= $(CROSS_COMPILE)strip
+endif
 PAHOLE		= pahole
 LEX		= flex
 YACC		= bison
@@ -538,7 +555,7 @@ endif
 ifneq ($(GCC_TOOLCHAIN),)
 CLANG_FLAGS	+= --gcc-toolchain=$(GCC_TOOLCHAIN)
 endif
-ifeq ($(if $(AS),$(shell $(AS) --version 2>&1 | head -n 1 | grep clang)),)
+ifneq ($(LLVM_IAS),1)
 CLANG_FLAGS	+= -no-integrated-as
 endif
 CLANG_FLAGS	+= -Werror=unknown-warning-option
@@ -747,8 +764,6 @@ ifdef CONFIG_CC_IS_CLANG
 KBUILD_CPPFLAGS += -Qunused-arguments
 KBUILD_CFLAGS += -Wno-format-invalid-specifier
 KBUILD_CFLAGS += -Wno-gnu
-# Quiet clang warning: comparison of unsigned expression < 0 is always false
-KBUILD_CFLAGS += -Wno-tautological-compare
 # 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.
 # See modpost pattern 2
@@ -1036,8 +1051,13 @@ init-y		:= $(patsubst %/, %/built-in.a, $(init-y))
 core-y		:= $(patsubst %/, %/built-in.a, $(core-y))
 drivers-y	:= $(patsubst %/, %/built-in.a, $(drivers-y))
 net-y		:= $(patsubst %/, %/built-in.a, $(net-y))
+libs-y2		:= $(patsubst %/, %/built-in.a, $(filter %/, $(libs-y)))
+ifdef CONFIG_MODULES
+libs-y1		:= $(filter-out %/, $(libs-y))
+libs-y2		+= $(patsubst %/, %/lib.a, $(filter %/, $(libs-y)))
+else
 libs-y1		:= $(patsubst %/, %/lib.a, $(libs-y))
-libs-y2		:= $(patsubst %/, %/built-in.a, $(filter-out %.a, $(libs-y)))
+endif
 virt-y		:= $(patsubst %/, %/built-in.a, $(virt-y))
 
 # Externally visible symbols (used by link-vmlinux.sh)

arch/h8300/include/uapi/asm/posix_types.h

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
+#ifndef _UAPI_ASM_POSIX_TYPES_H
+#define _UAPI_ASM_POSIX_TYPES_H
+
+/* h8300-unknown-linux required long */
+#define __kernel_size_t __kernel_size_t
+typedef unsigned long	__kernel_size_t;
+typedef long		__kernel_ssize_t;
+typedef long		__kernel_ptrdiff_t;
+
+#include <asm-generic/posix_types.h>
+
+#endif /* _UAPI_ASM_POSIX_TYPES_H */

arch/mips/fw/arc/memory.c

@@ -117,7 +117,7 @@ static int __init prom_memtype_classify(union linux_memtypes type)
 	return memtype_classify_arc(type);
 }
 
-void __init prom_meminit(void)
+void __weak __init prom_meminit(void)
 {
 	struct linux_mdesc *p;
 
@@ -162,7 +162,7 @@ void __weak __init prom_cleanup(void)
 {
 }
 
-void __init prom_free_prom_memory(void)
+void __weak __init prom_free_prom_memory(void)
 {
 	int i;
 

arch/sh/include/asm/bitops-op32.h

@@ -16,11 +16,9 @@
 #define BYTE_OFFSET(nr)		((nr) % BITS_PER_BYTE)
 #endif
 
-#define IS_IMMEDIATE(nr)	(__builtin_constant_p(nr))
-
 static inline void __set_bit(int nr, volatile unsigned long *addr)
 {
-	if (IS_IMMEDIATE(nr)) {
+	if (__builtin_constant_p(nr)) {
 		__asm__ __volatile__ (
 			"bset.b %1, @(%O2,%0)		! __set_bit\n\t"
 			: "+r" (addr)
@@ -37,7 +35,7 @@ static inline void __set_bit(int nr, volatile unsigned long *addr)
 
 static inline void __clear_bit(int nr, volatile unsigned long *addr)
 {
-	if (IS_IMMEDIATE(nr)) {
+	if (__builtin_constant_p(nr)) {
 		__asm__ __volatile__ (
 			"bclr.b %1, @(%O2,%0)		! __clear_bit\n\t"
 			: "+r" (addr)
@@ -64,7 +62,7 @@ static inline void __clear_bit(int nr, volatile unsigned long *addr)
  */
 static inline void __change_bit(int nr, volatile unsigned long *addr)
 {
-	if (IS_IMMEDIATE(nr)) {
+	if (__builtin_constant_p(nr)) {
 		__asm__ __volatile__ (
 			"bxor.b %1, @(%O2,%0)		! __change_bit\n\t"
 			: "+r" (addr)

arch/x86/Kconfig

@@ -2932,3 +2932,5 @@ config HAVE_ATOMIC_IOMAP
 source "drivers/firmware/Kconfig"
 
 source "arch/x86/kvm/Kconfig"
+
+source "arch/x86/Kconfig.assembler"

arch/x86/Kconfig.assembler

@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2020 Jason A. Donenfeld <[email protected]>. All Rights Reserved.
+
+config AS_AVX512
+	def_bool $(as-instr,vpmovm2b %k1$(comma)%zmm5)
+	help
+	  Supported by binutils >= 2.25 and LLVM integrated assembler
+
+config AS_SHA1_NI
+	def_bool $(as-instr,sha1msg1 %xmm0$(comma)%xmm1)
+	help
+	  Supported by binutils >= 2.24 and LLVM integrated assembler
+
+config AS_SHA256_NI
+	def_bool $(as-instr,sha256msg1 %xmm0$(comma)%xmm1)
+	help
+	  Supported by binutils >= 2.24 and LLVM integrated assembler

arch/x86/Makefile

@@ -177,28 +177,6 @@ ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
 	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
 endif
 
-# Stackpointer is addressed different for 32 bit and 64 bit x86
-sp-$(CONFIG_X86_32) := esp
-sp-$(CONFIG_X86_64) := rsp
-
-# do binutils support CFI?
-cfi := $(call as-instr,.cfi_startproc\n.cfi_rel_offset $(sp-y)$(comma)0\n.cfi_endproc,-DCONFIG_AS_CFI=1)
-# is .cfi_signal_frame supported too?
-cfi-sigframe := $(call as-instr,.cfi_startproc\n.cfi_signal_frame\n.cfi_endproc,-DCONFIG_AS_CFI_SIGNAL_FRAME=1)
-cfi-sections := $(call as-instr,.cfi_sections .debug_frame,-DCONFIG_AS_CFI_SECTIONS=1)
-
-# does binutils support specific instructions?
-asinstr += $(call as-instr,pshufb %xmm0$(comma)%xmm0,-DCONFIG_AS_SSSE3=1)
-avx_instr := $(call as-instr,vxorps %ymm0$(comma)%ymm1$(comma)%ymm2,-DCONFIG_AS_AVX=1)
-avx2_instr :=$(call as-instr,vpbroadcastb %xmm0$(comma)%ymm1,-DCONFIG_AS_AVX2=1)
-avx512_instr :=$(call as-instr,vpmovm2b %k1$(comma)%zmm5,-DCONFIG_AS_AVX512=1)
-sha1_ni_instr :=$(call as-instr,sha1msg1 %xmm0$(comma)%xmm1,-DCONFIG_AS_SHA1_NI=1)
-sha256_ni_instr :=$(call as-instr,sha256msg1 %xmm0$(comma)%xmm1,-DCONFIG_AS_SHA256_NI=1)
-adx_instr := $(call as-instr,adox %r10$(comma)%r10,-DCONFIG_AS_ADX=1)
-
-KBUILD_AFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr) $(adx_instr)
-KBUILD_CFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr) $(adx_instr)
-
 KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
 
 #