Merge tag 'kbuild-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Clean up Makefiles and scripts

 - Improve clang support

 - Remove unneeded genhdr-y syntax

 - Remove unneeded cc-option-align macro

 - Introduce __cc-option macro and use it to fix x86 boot code compiler
   flags

* tag 'kbuild-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: improve comments on KBUILD_SRC
  x86/build: Specify stack alignment for clang
  x86/build: Use __cc-option for boot code compiler options
  kbuild: Add __cc-option macro
  kbuild: remove cc-option-align
  kbuild: replace genhdr-y with generated-y
  kbuild: clang: Disable 'address-of-packed-member' warning
  kbuild: remove duplicated arch/*/include/generated/uapi include path
  kbuild: speed up checksyscalls.sh
  kbuild: simplify silent build (-s) detection

12 files changed, 67 insertions, 104 deletions

diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
index 659afd56ecdb..7003141a6d4f 100644
--- a/Documentation/kbuild/makefiles.txt
+++ b/Documentation/kbuild/makefiles.txt
@@ -45,10 +45,9 @@ This document describes the Linux kernel Makefiles.
 
 	=== 7 Kbuild syntax for exported headers
 		--- 7.1 no-export-headers
-		--- 7.2 genhdr-y
-		--- 7.3 generic-y
-		--- 7.4 generated-y
-		--- 7.5 mandatory-y
+		--- 7.2 generic-y
+		--- 7.3 generated-y
+		--- 7.4 mandatory-y
 
 	=== 8 Kbuild Variables
 	=== 9 Makefile language
@@ -487,22 +486,6 @@ more details, with real examples.
 	respectively.
 	Note: cc-option-yn uses KBUILD_CFLAGS for $(CC) options
 
-    cc-option-align
-	gcc versions >= 3.0 changed the type of options used to specify
-	alignment of functions, loops etc. $(cc-option-align), when used
-	as prefix to the align options, will select the right prefix:
-	gcc < 3.00
-		cc-option-align = -malign
-	gcc >= 3.00
-		cc-option-align = -falign
-
-	Example:
-		KBUILD_CFLAGS += $(cc-option-align)-functions=4
-
-	In the above example, the option -falign-functions=4 is used for
-	gcc >= 3.00. For gcc < 3.00, -malign-functions=4 is used.
-	Note: cc-option-align uses KBUILD_CFLAGS for $(CC) options
-
     cc-disable-warning
 	cc-disable-warning checks if gcc supports a given warning and returns
 	the commandline switch to disable it. This special function is needed,
@@ -1277,18 +1260,7 @@ See subsequent chapter for the syntax of the Kbuild file.
 	avoid exporting specific headers (e.g. kvm.h) on architectures that do
 	not support it. It should be avoided as much as possible.
 
-	--- 7.2 genhdr-y
-
-	genhdr-y specifies asm files to be generated.
-
-		Example:
-			#arch/x86/include/uapi/asm/Kbuild
-			genhdr-y += unistd_32.h
-			genhdr-y += unistd_64.h
-			genhdr-y += unistd_x32.h
-
-
-	--- 7.3 generic-y
+	--- 7.2 generic-y
 
 	If an architecture uses a verbatim copy of a header from
 	include/asm-generic then this is listed in the file
@@ -1315,11 +1287,10 @@ See subsequent chapter for the syntax of the Kbuild file.
 		Example: termios.h
 			#include <asm-generic/termios.h>
 
-	--- 7.4 generated-y
+	--- 7.3 generated-y
 
 	If an architecture generates other header files alongside generic-y
-	wrappers, and not included in genhdr-y, then generated-y specifies
-	them.
+	wrappers, generated-y specifies them.
 
 	This prevents them being treated as stale asm-generic wrappers and
 	removed.
diff --git a/Makefile b/Makefile
index d7cb0372bed9..faea0e37c2f2 100644
--- a/Makefile
+++ b/Makefile
@@ -84,17 +84,10 @@ endif
 # If the user is running make -s (silent mode), suppress echoing of
 # commands
 
-ifneq ($(filter 4.%,$(MAKE_VERSION)),)	# make-4
-ifneq ($(filter %s ,$(firstword x$(MAKEFLAGS))),)
+ifneq ($(findstring s,$(filter-out --%,$(MAKEFLAGS))),)
   quiet=silent_
   tools_silent=s
 endif
-else					# make-3.8x
-ifneq ($(filter s% -s%,$(MAKEFLAGS)),)
-  quiet=silent_
-  tools_silent=-s
-endif
-endif
 
 export quiet Q KBUILD_VERBOSE
 
@@ -113,8 +106,8 @@ export quiet Q KBUILD_VERBOSE
 # The O= assignment takes precedence over the KBUILD_OUTPUT environment
 # variable.
 
-# KBUILD_SRC is set on invocation of make in OBJ directory
-# KBUILD_SRC is not intended to be used by the regular user (for now)
+# KBUILD_SRC is not intended to be used by the regular user (for now),
+# it is set on invocation of make with KBUILD_OUTPUT or O= specified.
 ifeq ($(KBUILD_SRC),)
 
 # OK, Make called in directory where kernel src resides
@@ -135,7 +128,6 @@ ifneq ($(words $(subst :, ,$(CURDIR))), 1)
 endif
 
 ifneq ($(KBUILD_OUTPUT),)
-# Invoke a second make in the output directory, passing relevant variables
 # check that the output directory actually exists
 saved-output := $(KBUILD_OUTPUT)
 KBUILD_OUTPUT := $(shell mkdir -p $(KBUILD_OUTPUT) && cd $(KBUILD_OUTPUT) \
@@ -148,6 +140,7 @@ PHONY += $(MAKECMDGOALS) sub-make
 $(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make
 	@:
 
+# Invoke a second make in the output directory, passing relevant variables
 sub-make:
 	$(Q)$(MAKE) -C $(KBUILD_OUTPUT) KBUILD_SRC=$(CURDIR) \
 	-f $(CURDIR)/Makefile $(filter-out _all sub-make,$(MAKECMDGOALS))
@@ -303,7 +296,7 @@ CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \
 
 HOSTCC       = gcc
 HOSTCXX      = g++
-HOSTCFLAGS   = -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer -std=gnu89
+HOSTCFLAGS   := -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer -std=gnu89
 HOSTCXXFLAGS = -O2
 
 ifeq ($(shell $(HOSTCC) -v 2>&1 | grep -c "clang version"), 1)
@@ -388,12 +381,10 @@ USERINCLUDE    := \
 # Needed to be compatible with the O= option
 LINUXINCLUDE    := \
 		-I$(srctree)/arch/$(hdr-arch)/include \
-		-I$(objtree)/arch/$(hdr-arch)/include/generated/uapi \
 		-I$(objtree)/arch/$(hdr-arch)/include/generated \
 		$(if $(KBUILD_SRC), -I$(srctree)/include) \
-		-I$(objtree)/include
-
-LINUXINCLUDE	+= $(filter-out $(LINUXINCLUDE),$(USERINCLUDE))
+		-I$(objtree)/include \
+		$(USERINCLUDE)
 
 KBUILD_CPPFLAGS := -D__KERNEL__
 
@@ -707,6 +698,7 @@ KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,)
 KBUILD_CFLAGS += $(call cc-disable-warning, unused-variable)
 KBUILD_CFLAGS += $(call cc-disable-warning, format-invalid-specifier)
 KBUILD_CFLAGS += $(call cc-disable-warning, gnu)
+KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member)
 # Quiet clang warning: comparison of unsigned expression < 0 is always false
 KBUILD_CFLAGS += $(call cc-disable-warning, tautological-compare)
 # CLANG uses a _MergedGlobals as optimization, but this breaks modpost, as the
diff --git a/arch/arm/include/uapi/asm/Kbuild b/arch/arm/include/uapi/asm/Kbuild
index e9b098d6b766..5fb3368e70cb 100644
--- a/arch/arm/include/uapi/asm/Kbuild
+++ b/arch/arm/include/uapi/asm/Kbuild
@@ -1,8 +1,8 @@
 # UAPI Header export list
 include include/uapi/asm-generic/Kbuild.asm
 
-genhdr-y += unistd-common.h
-genhdr-y += unistd-oabi.h
-genhdr-y += unistd-eabi.h
+generated-y += unistd-common.h
+generated-y += unistd-oabi.h
+generated-y += unistd-eabi.h
 
 generic-y += siginfo.h
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index ad2db82e9953..1e902f926be3 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -11,6 +11,14 @@ else
         KBUILD_DEFCONFIG := $(ARCH)_defconfig
 endif
 
+# For gcc stack alignment is specified with -mpreferred-stack-boundary,
+# clang has the option -mstack-alignment for that purpose.
+ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
+        cc_stack_align_opt := -mpreferred-stack-boundary
+else ifneq ($(call cc-option, -mstack-alignment=4),)
+        cc_stack_align_opt := -mstack-alignment
+endif
+
 # How to compile the 16-bit code.  Note we always compile for -march=i386;
 # that way we can complain to the user if the CPU is insufficient.
 #
@@ -24,10 +32,11 @@ REALMODE_CFLAGS	:= $(M16_CFLAGS) -g -Os -D__KERNEL__ \
 		   -DDISABLE_BRANCH_PROFILING \
 		   -Wall -Wstrict-prototypes -march=i386 -mregparm=3 \
 		   -fno-strict-aliasing -fomit-frame-pointer -fno-pic \
-		   -mno-mmx -mno-sse \
-		   $(call cc-option, -ffreestanding) \
-		   $(call cc-option, -fno-stack-protector) \
-		   $(call cc-option, -mpreferred-stack-boundary=2)
+		   -mno-mmx -mno-sse
+
+REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -ffreestanding)
+REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -fno-stack-protector)
+REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align_opt)=2)
 export REALMODE_CFLAGS
 
 # BITS is used as extension for files which are available in a 32 bit
@@ -64,8 +73,10 @@ ifeq ($(CONFIG_X86_32),y)
         # with nonstandard options
         KBUILD_CFLAGS += -fno-pic
 
-        # prevent gcc from keeping the stack 16 byte aligned
-        KBUILD_CFLAGS += $(call cc-option,-mpreferred-stack-boundary=2)
+        # Align the stack to the register width instead of using the default
+        # alignment of 16 bytes. This reduces stack usage and the number of
+        # alignment instructions.
+        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align_opt)=2)
 
         # Disable unit-at-a-time mode on pre-gcc-4.0 compilers, it makes gcc use
         # a lot more stack due to the lack of sharing of stacklots:
@@ -97,8 +108,14 @@ else
         KBUILD_CFLAGS += $(call cc-option,-mno-80387)
         KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
 
-	# Use -mpreferred-stack-boundary=3 if supported.
-	KBUILD_CFLAGS += $(call cc-option,-mpreferred-stack-boundary=3)
+        # By default gcc and clang use a stack alignment of 16 bytes for x86.
+        # However the standard kernel entry on x86-64 leaves the stack on an
+        # 8-byte boundary. If the compiler isn't informed about the actual
+        # alignment it will generate extra alignment instructions for the
+        # default alignment which keep the stack *mis*aligned.
+        # Furthermore an alignment to the register width reduces stack usage
+        # and the number of alignment instructions.
+        KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align_opt)=3)
 
 	# Use -mskip-rax-setup if supported.
 	KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)
diff --git a/arch/x86/Makefile_32.cpu b/arch/x86/Makefile_32.cpu
index a45eb15b7cf2..f3717d36718a 100644
--- a/arch/x86/Makefile_32.cpu
+++ b/arch/x86/Makefile_32.cpu
@@ -9,7 +9,6 @@ else
 tune		= $(call cc-option,-mcpu=$(1),$(2))
 endif
 
-align := $(cc-option-align)
 cflags-$(CONFIG_M486)		+= -march=i486
 cflags-$(CONFIG_M586)		+= -march=i586
 cflags-$(CONFIG_M586TSC)	+= -march=i586
@@ -24,11 +23,11 @@ cflags-$(CONFIG_MK6)		+= -march=k6
 # They make zero difference whatsosever to performance at this time.
 cflags-$(CONFIG_MK7)		+= -march=athlon
 cflags-$(CONFIG_MK8)		+= $(call cc-option,-march=k8,-march=athlon)
-cflags-$(CONFIG_MCRUSOE)	+= -march=i686 $(align)-functions=0 $(align)-jumps=0 $(align)-loops=0
-cflags-$(CONFIG_MEFFICEON)	+= -march=i686 $(call tune,pentium3) $(align)-functions=0 $(align)-jumps=0 $(align)-loops=0
+cflags-$(CONFIG_MCRUSOE)	+= -march=i686 -falign-functions=0 -falign-jumps=0 -falign-loops=0
+cflags-$(CONFIG_MEFFICEON)	+= -march=i686 $(call tune,pentium3) -falign-functions=0 -falign-jumps=0 -falign-loops=0
 cflags-$(CONFIG_MWINCHIPC6)	+= $(call cc-option,-march=winchip-c6,-march=i586)
 cflags-$(CONFIG_MWINCHIP3D)	+= $(call cc-option,-march=winchip2,-march=i586)
-cflags-$(CONFIG_MCYRIXIII)	+= $(call cc-option,-march=c3,-march=i486) $(align)-functions=0 $(align)-jumps=0 $(align)-loops=0
+cflags-$(CONFIG_MCYRIXIII)	+= $(call cc-option,-march=c3,-march=i486) -falign-functions=0 -falign-jumps=0 -falign-loops=0
 cflags-$(CONFIG_MVIAC3_2)	+= $(call cc-option,-march=c3-2,-march=i686)
 cflags-$(CONFIG_MVIAC7)		+= -march=i686
 cflags-$(CONFIG_MCORE2)		+= -march=i686 $(call tune,core2)
diff --git a/arch/x86/include/uapi/asm/Kbuild b/arch/x86/include/uapi/asm/Kbuild
index 83b6e9a0dce4..da1489cb64dc 100644
--- a/arch/x86/include/uapi/asm/Kbuild
+++ b/arch/x86/include/uapi/asm/Kbuild
@@ -1,6 +1,6 @@
 # UAPI Header export list
 include include/uapi/asm-generic/Kbuild.asm
 
-genhdr-y += unistd_32.h
-genhdr-y += unistd_64.h
-genhdr-y += unistd_x32.h
+generated-y += unistd_32.h
+generated-y += unistd_64.h
+generated-y += unistd_x32.h
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 61f87a99bf0a..dd8e2dde0b34 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -108,6 +108,11 @@ as-option = $(call try-run,\
 as-instr = $(call try-run,\
 	printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3))
 
+# __cc-option
+# Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586)
+__cc-option = $(call try-run,\
+	$(1) -Werror $(2) $(3) -c -x c /dev/null -o "$$TMP",$(3),$(4))
+
 # Do not attempt to build with gcc plugins during cc-option tests.
 # (And this uses delayed resolution so the flags will be up to date.)
 CC_OPTION_CFLAGS = $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS))
@@ -115,19 +120,19 @@ CC_OPTION_CFLAGS = $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS))
 # cc-option
 # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
 
-cc-option = $(call try-run,\
-	$(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
+cc-option = $(call __cc-option, $(CC),\
+	$(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS),$(1),$(2))
+
+# hostcc-option
+# Usage: cflags-y += $(call hostcc-option,-march=winchip-c6,-march=i586)
+hostcc-option = $(call __cc-option, $(HOSTCC),\
+	$(HOSTCFLAGS) $(HOST_EXTRACFLAGS),$(1),$(2))
 
 # cc-option-yn
 # Usage: flag := $(call cc-option-yn,-march=winchip-c6)
 cc-option-yn = $(call try-run,\
 	$(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)
 
-# cc-option-align
-# Prefix align with either -falign or -malign
-cc-option-align = $(subst -functions=0,,\
-	$(call cc-option,-falign-functions=0,-malign-functions=0))
-
 # cc-disable-warning
 # Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
 cc-disable-warning = $(call try-run,\
diff --git a/scripts/Makefile.asm-generic b/scripts/Makefile.asm-generic
index e4d017d53819..95f7d8090152 100644
--- a/scripts/Makefile.asm-generic
+++ b/scripts/Makefile.asm-generic
@@ -15,7 +15,7 @@ _dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
 
 # Stale wrappers when the corresponding files are removed from generic-y
 # need removing.
-generated-y   := $(generic-y) $(genhdr-y) $(generated-y)
+generated-y   := $(generic-y) $(generated-y)
 all-files     := $(patsubst %, $(obj)/%, $(generated-y))
 old-headers   := $(wildcard $(obj)/*.h)
 unwanted      := $(filter-out $(all-files),$(old-headers))
diff --git a/scripts/Makefile.host b/scripts/Makefile.host
index 45b5b1aaedbd..9cfd5c84d76f 100644
--- a/scripts/Makefile.host
+++ b/scripts/Makefile.host
@@ -20,12 +20,6 @@
 # Will compile qconf as a C++ program, and menu as a C program.
 # They are linked as C++ code to the executable qconf
 
-# hostcc-option
-# Usage: cflags-y += $(call hostcc-option,-march=winchip-c6,-march=i586)
-
-hostcc-option = $(call try-run,\
-	$(HOSTCC) $(HOSTCFLAGS) $(HOST_EXTRACFLAGS) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
-
 __hostprogs := $(sort $(hostprogs-y) $(hostprogs-m))
 host-cshlib := $(sort $(hostlibs-y) $(hostlibs-m))
 host-cxxshlib := $(sort $(hostcxxlibs-y) $(hostcxxlibs-m))
diff --git a/scripts/checksyscalls.sh b/scripts/checksyscalls.sh
index 116b7735ee9f..5a387a264201 100755
--- a/scripts/checksyscalls.sh
+++ b/scripts/checksyscalls.sh
@@ -202,15 +202,12 @@ EOF
 }
 
 syscall_list() {
-    grep '^[0-9]' "$1" | sort -n | (
+    grep '^[0-9]' "$1" | sort -n |
 	while read nr abi name entry ; do
-	    cat <<EOF
-#if !defined(__NR_${name}) && !defined(__IGNORE_${name})
-#warning syscall ${name} not implemented
-#endif
-EOF
+		echo "#if !defined(__NR_${name}) && !defined(__IGNORE_${name})"
+		echo "#warning syscall ${name} not implemented"
+		echo "#endif"
 	done
-    )
 }
 
 (ignore_list && syscall_list $(dirname $0)/../arch/x86/entry/syscalls/syscall_32.tbl) | \
diff --git a/tools/build/Makefile.build b/tools/build/Makefile.build
index e279a71c650d..c46b20e4ad87 100644
--- a/tools/build/Makefile.build
+++ b/tools/build/Makefile.build
@@ -19,15 +19,9 @@ else
   Q=@
 endif
 
-ifneq ($(filter 4.%,$(MAKE_VERSION)),)	# make-4
-ifneq ($(filter %s ,$(firstword x$(MAKEFLAGS))),)
+ifneq ($(findstring s,$(filter-out --%,$(MAKEFLAGS))),)
   quiet=silent_
 endif
-else					# make-3.8x
-ifneq ($(filter s% -s%,$(MAKEFLAGS)),)
-  quiet=silent_
-endif
-endif
 
 build-dir := $(srctree)/tools/build
 
diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include
index fc74db62fef4..ccad8ce925e4 100644
--- a/tools/scripts/Makefile.include
+++ b/tools/scripts/Makefile.include
@@ -58,15 +58,9 @@ else
 NO_SUBDIR = :
 endif
 
-ifneq ($(filter 4.%,$(MAKE_VERSION)),)  # make-4
-ifneq ($(filter %s ,$(firstword x$(MAKEFLAGS))),)
+ifneq ($(findstring s,$(filter-out --%,$(MAKEFLAGS))),)
   silent=1
 endif
-else					# make-3.8x
-ifneq ($(filter s% -s%,$(MAKEFLAGS)),)
-  silent=1
-endif
-endif
 
 #
 # Define a callable command for descending to a new directory