From a5575df58004e8444e5a2a307407c3f1a6ecf175 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Tue, 25 Jan 2022 15:40:27 +0900
Subject: [PATCH 01/13] kbuild: unify cmd_copy and cmd_shipped

cmd_copy and cmd_shipped have similar functionality. The difference is
that cmd_copy uses 'cp' while cmd_shipped 'cat'.

Unify them into cmd_copy because this macro name is more intuitive.

Going forward, cmd_copy will use 'cat' to avoid the permission issue.
I also thought of 'cp --no-preserve=mode' but this option is not
mentioned in the POSIX spec [1], so I am keeping the 'cat' command.

[1]: https://pubs.opengroup.org/onlinepubs/009695299/utilities/cp.html
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Gabriel Krisman Bertazi <krisman@collabora.com>
---
 arch/microblaze/boot/Makefile     |  2 +-
 arch/microblaze/boot/dts/Makefile |  2 +-
 fs/unicode/Makefile               |  2 +-
 scripts/Makefile.lib              | 12 ++++--------
 usr/Makefile                      |  4 ++--
 5 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/arch/microblaze/boot/Makefile b/arch/microblaze/boot/Makefile
index cff570a71946..2b42c370d574 100644
--- a/arch/microblaze/boot/Makefile
+++ b/arch/microblaze/boot/Makefile
@@ -29,7 +29,7 @@ $(obj)/simpleImage.$(DTB).ub: $(obj)/simpleImage.$(DTB) FORCE
 	$(call if_changed,uimage)
 
 $(obj)/simpleImage.$(DTB).unstrip: vmlinux FORCE
-	$(call if_changed,shipped)
+	$(call if_changed,copy)
 
 $(obj)/simpleImage.$(DTB).strip: vmlinux FORCE
 	$(call if_changed,strip)
diff --git a/arch/microblaze/boot/dts/Makefile b/arch/microblaze/boot/dts/Makefile
index ef00dd30d19a..b84e2cbb20ee 100644
--- a/arch/microblaze/boot/dts/Makefile
+++ b/arch/microblaze/boot/dts/Makefile
@@ -12,7 +12,7 @@ $(obj)/linked_dtb.o: $(obj)/system.dtb
 # Generate system.dtb from $(DTB).dtb
 ifneq ($(DTB),system)
 $(obj)/system.dtb: $(obj)/$(DTB).dtb
-	$(call if_changed,shipped)
+	$(call if_changed,copy)
 endif
 endif
 
diff --git a/fs/unicode/Makefile b/fs/unicode/Makefile
index 0cc87423de82..0e51c0025a16 100644
--- a/fs/unicode/Makefile
+++ b/fs/unicode/Makefile
@@ -33,7 +33,7 @@ $(obj)/utf8data.c: $(obj)/mkutf8data $(filter %.txt, $(cmd_utf8data)) FORCE
 else
 
 $(obj)/utf8data.c: $(src)/utf8data.c_shipped FORCE
-	$(call if_changed,shipped)
+	$(call if_changed,copy)
 
 endif
 
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 79be57fdd32a..40735a3adb54 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -246,20 +246,16 @@ $(foreach m, $(notdir $1), \
 	$(addprefix $(obj)/, $(foreach s, $3, $($(m:%$(strip $2)=%$(s)))))))
 endef
 
-quiet_cmd_copy = COPY    $@
-      cmd_copy = cp $< $@
-
-# Shipped files
+# Copy a file
 # ===========================================================================
 # 'cp' preserves permissions. If you use it to copy a file in read-only srctree,
 # the copy would be read-only as well, leading to an error when executing the
 # rule next time. Use 'cat' instead in order to generate a writable file.
-
-quiet_cmd_shipped = SHIPPED $@
-cmd_shipped = cat $< > $@
+quiet_cmd_copy = COPY    $@
+      cmd_copy = cat $< > $@
 
 $(obj)/%: $(src)/%_shipped
-	$(call cmd,shipped)
+	$(call cmd,copy)
 
 # Commands useful for building a boot image
 # ===========================================================================
diff --git a/usr/Makefile b/usr/Makefile
index cc0d2824e100..59d9e8b07a01 100644
--- a/usr/Makefile
+++ b/usr/Makefile
@@ -3,7 +3,7 @@
 # kbuild file for usr/ - including initramfs image
 #
 
-compress-y					:= shipped
+compress-y					:= copy
 compress-$(CONFIG_INITRAMFS_COMPRESSION_GZIP)	:= gzip
 compress-$(CONFIG_INITRAMFS_COMPRESSION_BZIP2)	:= bzip2
 compress-$(CONFIG_INITRAMFS_COMPRESSION_LZMA)	:= lzma
@@ -37,7 +37,7 @@ endif
 # .cpio.*, use it directly as an initramfs, and avoid double compression.
 ifeq ($(words $(subst .cpio.,$(space),$(ramfs-input))),2)
 cpio-data := $(ramfs-input)
-compress-y := shipped
+compress-y := copy
 endif
 
 endif

From f67695c9962e5f444549b3437fb8d840ec6222c8 Mon Sep 17 00:00:00 2001
From: Elliot Berman <quic_eberman@quicinc.com>
Date: Tue, 1 Feb 2022 13:35:42 -0800
Subject: [PATCH 02/13] kbuild: Add environment variables for userprogs flags

Allow additional arguments be passed to userprogs compilation.
Reproducible clang builds need to provide a sysroot and gcc path to
ensure the same toolchain is used across hosts. KCFLAGS is not currently
used for any user programs compilation, so add new USERCFLAGS and
USERLDFLAGS which serves similar purpose as HOSTCFLAGS/HOSTLDFLAGS.

Clang might detect GCC installation on hosts which have it installed
to a default location in /. With addition of these environment
variables, you can specify flags such as:

$ make USERCFLAGS=--sysroot=/path/to/sysroot

This can also be used to specify different sysroots such as musl or
bionic which may be installed on the host in paths that the compiler
may not search by default.

Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Fangrui Song <maskray@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
 Documentation/kbuild/kbuild.rst    | 11 +++++++++++
 Documentation/kbuild/makefiles.rst |  2 ++
 Makefile                           | 10 ++++++----
 init/Kconfig                       |  8 ++++----
 usr/include/Makefile               |  3 +++
 5 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/Documentation/kbuild/kbuild.rst b/Documentation/kbuild/kbuild.rst
index 2d1fc03d346e..ef19b9c13523 100644
--- a/Documentation/kbuild/kbuild.rst
+++ b/Documentation/kbuild/kbuild.rst
@@ -77,6 +77,17 @@ HOSTLDLIBS
 ----------
 Additional libraries to link against when building host programs.
 
+.. _userkbuildflags:
+
+USERCFLAGS
+----------
+Additional options used for $(CC) when compiling userprogs.
+
+USERLDFLAGS
+-----------
+Additional options used for $(LD) when linking userprogs. userprogs are linked
+with CC, so $(USERLDFLAGS) should include "-Wl," prefix as applicable.
+
 KBUILD_KCONFIG
 --------------
 Set the top-level Kconfig file to the value of this environment
diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
index b008b90b92c9..11a296e52d68 100644
--- a/Documentation/kbuild/makefiles.rst
+++ b/Documentation/kbuild/makefiles.rst
@@ -982,6 +982,8 @@ The syntax is quite similar. The difference is to use "userprogs" instead of
 
 	When linking bpfilter_umh, it will be passed the extra option -static.
 
+	From command line, :ref:`USERCFLAGS and USERLDFLAGS <userkbuildflags>` will also be used.
+
 5.4 When userspace programs are actually built
 ----------------------------------------------
 
diff --git a/Makefile b/Makefile
index 51e142f760f7..351f043e133a 100644
--- a/Makefile
+++ b/Makefile
@@ -431,11 +431,12 @@ HOSTCC	= gcc
 HOSTCXX	= g++
 endif
 
-export KBUILD_USERCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
-			      -O2 -fomit-frame-pointer -std=gnu89
-export KBUILD_USERLDFLAGS :=
+KBUILD_USERHOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
+			 -O2 -fomit-frame-pointer -std=gnu89
+KBUILD_USERCFLAGS  := $(KBUILD_USERHOSTCFLAGS) $(USERCFLAGS)
+KBUILD_USERLDFLAGS := $(USERLDFLAGS)
 
-KBUILD_HOSTCFLAGS   := $(KBUILD_USERCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS)
+KBUILD_HOSTCFLAGS   := $(KBUILD_USERHOSTCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS)
 KBUILD_HOSTCXXFLAGS := -Wall -O2 $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS)
 KBUILD_HOSTLDFLAGS  := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS)
 KBUILD_HOSTLDLIBS   := $(HOST_LFS_LIBS) $(HOSTLDLIBS)
@@ -530,6 +531,7 @@ export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS LEX YACC AW
 export PERL PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
 export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD
 export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE
+export KBUILD_USERCFLAGS KBUILD_USERLDFLAGS
 
 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS
 export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
diff --git a/init/Kconfig b/init/Kconfig
index e9119bf54b1f..a2f881cc84d6 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -62,13 +62,13 @@ config LLD_VERSION
 
 config CC_CAN_LINK
 	bool
-	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m64-flag)) if 64BIT
-	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m32-flag))
+	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag)) if 64BIT
+	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m32-flag))
 
 config CC_CAN_LINK_STATIC
 	bool
-	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m64-flag) -static) if 64BIT
-	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m32-flag) -static)
+	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag) -static) if 64BIT
+	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m32-flag) -static)
 
 config CC_HAS_ASM_GOTO
 	def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC))
diff --git a/usr/include/Makefile b/usr/include/Makefile
index 83822c33e9e7..5bc0d566cfe0 100644
--- a/usr/include/Makefile
+++ b/usr/include/Makefile
@@ -12,6 +12,9 @@ UAPI_CFLAGS := -std=c90 -Wall -Werror=implicit-function-declaration
 # It is here just because CONFIG_CC_CAN_LINK is tested with -m32 or -m64.
 UAPI_CFLAGS += $(filter -m32 -m64, $(KBUILD_CFLAGS))
 
+# USERCFLAGS might contain sysroot location for CC.
+UAPI_CFLAGS += $(USERCFLAGS)
+
 override c_flags = $(UAPI_CFLAGS) -Wp,-MMD,$(depfile) -I$(objtree)/usr/include
 
 # The following are excluded for now because they fail to build.

From 5c8166419acf468b5bc3e48f928a040485d3e0c2 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Fri, 11 Feb 2022 14:14:11 +0900
Subject: [PATCH 03/13] kbuild: replace $(if A,A,B) with $(or A,B)

$(or ...) is available since GNU Make 3.81, and useful to shorten the
code in some places.

Covert as follows:

  $(if A,A,B)  -->  $(or A,B)

This patch also converts:

  $(if A, A, B) --> $(or A, B)

Strictly speaking, the latter is not an equivalent conversion because
GNU Make keeps spaces after commas; if A is not empty, $(if A, A, B)
expands to " A", while $(or A, B) expands to "A".

Anyway, preceding spaces are not significant in the code hunks I touched.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
---
 Makefile                                    | 8 ++++----
 scripts/Makefile.build                      | 3 +--
 scripts/Makefile.clean                      | 2 +-
 scripts/Makefile.lib                        | 4 ++--
 tools/bpf/bpftool/Makefile                  | 4 ++--
 tools/build/Makefile                        | 2 +-
 tools/counter/Makefile                      | 2 +-
 tools/gpio/Makefile                         | 2 +-
 tools/hv/Makefile                           | 2 +-
 tools/iio/Makefile                          | 2 +-
 tools/lib/api/Makefile                      | 2 +-
 tools/lib/bpf/Makefile                      | 2 +-
 tools/lib/perf/Makefile                     | 2 +-
 tools/lib/subcmd/Makefile                   | 2 +-
 tools/objtool/Makefile                      | 2 +-
 tools/pci/Makefile                          | 2 +-
 tools/perf/Makefile.perf                    | 4 ++--
 tools/power/x86/intel-speed-select/Makefile | 2 +-
 tools/scripts/utilities.mak                 | 2 +-
 tools/spi/Makefile                          | 6 +++---
 tools/tracing/rtla/Makefile                 | 2 +-
 tools/usb/Makefile                          | 2 +-
 22 files changed, 30 insertions(+), 31 deletions(-)

diff --git a/Makefile b/Makefile
index 351f043e133a..a82095c69fdd 100644
--- a/Makefile
+++ b/Makefile
@@ -1240,8 +1240,8 @@ define filechk_version.h
 	echo \#define LINUX_VERSION_SUBLEVEL $(SUBLEVEL)
 endef
 
-$(version_h): PATCHLEVEL := $(if $(PATCHLEVEL), $(PATCHLEVEL), 0)
-$(version_h): SUBLEVEL := $(if $(SUBLEVEL), $(SUBLEVEL), 0)
+$(version_h): PATCHLEVEL := $(or $(PATCHLEVEL), 0)
+$(version_h): SUBLEVEL := $(or $(SUBLEVEL), 0)
 $(version_h): FORCE
 	$(call filechk,version.h)
 
@@ -1624,7 +1624,7 @@ help:
 	@$(MAKE) -f $(srctree)/Documentation/Makefile dochelp
 	@echo  ''
 	@echo  'Architecture specific targets ($(SRCARCH)):'
-	@$(if $(archhelp),$(archhelp),\
+	@$(or $(archhelp),\
 		echo '  No architecture specific help defined for $(SRCARCH)')
 	@echo  ''
 	@$(if $(boards), \
@@ -1841,7 +1841,7 @@ $(clean-dirs):
 
 clean: $(clean-dirs)
 	$(call cmd,rmfiles)
-	@find $(if $(KBUILD_EXTMOD), $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
+	@find $(or $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
 		\( -name '*.[aios]' -o -name '*.ko' -o -name '.*.cmd' \
 		-o -name '*.ko.*' \
 		-o -name '*.dtb' -o -name '*.dtbo' -o -name '*.dtb.S' -o -name '*.dt.yaml' \
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index a4b89b757287..7e177d0ee02d 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -40,8 +40,7 @@ include $(srctree)/scripts/Makefile.compiler
 
 # The filename Kbuild has precedence over Makefile
 kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
-kbuild-file := $(if $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Kbuild,$(kbuild-dir)/Makefile)
-include $(kbuild-file)
+include $(or $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Makefile)
 
 include $(srctree)/scripts/Makefile.lib
 
diff --git a/scripts/Makefile.clean b/scripts/Makefile.clean
index fd6175322470..74cb1c5c3658 100644
--- a/scripts/Makefile.clean
+++ b/scripts/Makefile.clean
@@ -12,7 +12,7 @@ include $(srctree)/scripts/Kbuild.include
 
 # The filename Kbuild has precedence over Makefile
 kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
-include $(if $(wildcard $(kbuild-dir)/Kbuild), $(kbuild-dir)/Kbuild, $(kbuild-dir)/Makefile)
+include $(or $(wildcard $(kbuild-dir)/Kbuild),$(kbuild-dir)/Makefile)
 
 # Figure out what we need to build from the various variables
 # ==========================================================================
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 40735a3adb54..49377d2c2d20 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -111,7 +111,7 @@ subdir-ym	:= $(addprefix $(obj)/,$(subdir-ym))
 modname-multi = $(sort $(foreach m,$(multi-obj-ym),\
 		$(if $(filter $*.o, $(call suffix-search, $m, .o, -objs -y -m)),$(m:.o=))))
 
-__modname = $(if $(modname-multi),$(modname-multi),$(basetarget))
+__modname = $(or $(modname-multi),$(basetarget))
 
 modname = $(subst $(space),:,$(__modname))
 modfile = $(addprefix $(obj)/,$(__modname))
@@ -434,7 +434,7 @@ MKIMAGE := $(srctree)/scripts/mkuboot.sh
 # SRCARCH just happens to match slightly more than ARCH (on sparc), so reduces
 # the number of overrides in arch makefiles
 UIMAGE_ARCH ?= $(SRCARCH)
-UIMAGE_COMPRESSION ?= $(if $(2),$(2),none)
+UIMAGE_COMPRESSION ?= $(or $(2),none)
 UIMAGE_OPTS-y ?=
 UIMAGE_TYPE ?= kernel
 UIMAGE_LOADADDR ?= arch_must_set_this
diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index 83369f55df61..ebd21a609910 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -78,7 +78,7 @@ CFLAGS += -O2
 CFLAGS += -W -Wall -Wextra -Wno-unused-parameter -Wno-missing-field-initializers
 CFLAGS += $(filter-out -Wswitch-enum -Wnested-externs,$(EXTRA_WARNINGS))
 CFLAGS += -DPACKAGE='"bpftool"' -D__EXPORTED_HEADERS__ \
-	-I$(if $(OUTPUT),$(OUTPUT),.) \
+	-I$(or $(OUTPUT),.) \
 	-I$(LIBBPF_INCLUDE) \
 	-I$(srctree)/kernel/bpf/ \
 	-I$(srctree)/tools/include \
@@ -186,7 +186,7 @@ endif
 
 $(OUTPUT)%.bpf.o: skeleton/%.bpf.c $(OUTPUT)vmlinux.h $(LIBBPF_BOOTSTRAP)
 	$(QUIET_CLANG)$(CLANG) \
-		-I$(if $(OUTPUT),$(OUTPUT),.) \
+		-I$(or $(OUTPUT),.) \
 		-I$(srctree)/tools/include/uapi/ \
 		-I$(LIBBPF_BOOTSTRAP_INCLUDE) \
 		-g -O2 -Wall -target bpf -c $< -o $@
diff --git a/tools/build/Makefile b/tools/build/Makefile
index 6f11e6fc9ffe..17cdf01e29a0 100644
--- a/tools/build/Makefile
+++ b/tools/build/Makefile
@@ -36,7 +36,7 @@ TMP_O := $(if $(OUTPUT),$(OUTPUT)feature/,./)
 
 clean:
 	$(call QUIET_CLEAN, fixdep)
-	$(Q)find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.cmd' -delete -o -name '\.*.d' -delete
+	$(Q)find $(or $(OUTPUT),.) -name '*.o' -delete -o -name '\.*.cmd' -delete -o -name '\.*.d' -delete
 	$(Q)rm -f $(OUTPUT)fixdep
 	$(call QUIET_CLEAN, feature-detect)
 ifneq ($(wildcard $(TMP_O)),)
diff --git a/tools/counter/Makefile b/tools/counter/Makefile
index 5ebc195fd9c0..8843f0fa6119 100644
--- a/tools/counter/Makefile
+++ b/tools/counter/Makefile
@@ -40,7 +40,7 @@ $(OUTPUT)counter_example: $(COUNTER_EXAMPLE)
 clean:
 	rm -f $(ALL_PROGRAMS)
 	rm -rf $(OUTPUT)include/linux/counter.h
-	find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
+	find $(or $(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
 
 install: $(ALL_PROGRAMS)
 	install -d -m 755 $(DESTDIR)$(bindir);		\
diff --git a/tools/gpio/Makefile b/tools/gpio/Makefile
index 440434027557..d29c9c49e251 100644
--- a/tools/gpio/Makefile
+++ b/tools/gpio/Makefile
@@ -78,7 +78,7 @@ $(OUTPUT)gpio-watch: $(GPIO_WATCH_IN)
 clean:
 	rm -f $(ALL_PROGRAMS)
 	rm -f $(OUTPUT)include/linux/gpio.h
-	find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
+	find $(or $(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
 
 install: $(ALL_PROGRAMS)
 	install -d -m 755 $(DESTDIR)$(bindir);		\
diff --git a/tools/hv/Makefile b/tools/hv/Makefile
index b57143d9459c..fe770e679ae8 100644
--- a/tools/hv/Makefile
+++ b/tools/hv/Makefile
@@ -47,7 +47,7 @@ $(OUTPUT)hv_fcopy_daemon: $(HV_FCOPY_DAEMON_IN)
 
 clean:
 	rm -f $(ALL_PROGRAMS)
-	find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
+	find $(or $(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
 
 install: $(ALL_PROGRAMS)
 	install -d -m 755 $(DESTDIR)$(sbindir); \
diff --git a/tools/iio/Makefile b/tools/iio/Makefile
index 5d12ac4e7f8f..fa720f062229 100644
--- a/tools/iio/Makefile
+++ b/tools/iio/Makefile
@@ -58,7 +58,7 @@ $(OUTPUT)iio_generic_buffer: $(IIO_GENERIC_BUFFER_IN)
 clean:
 	rm -f $(ALL_PROGRAMS)
 	rm -rf $(OUTPUT)include/linux/iio
-	find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
+	find $(or $(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
 
 install: $(ALL_PROGRAMS)
 	install -d -m 755 $(DESTDIR)$(bindir);		\
diff --git a/tools/lib/api/Makefile b/tools/lib/api/Makefile
index a13e9c7f1fc5..e21e1b40b525 100644
--- a/tools/lib/api/Makefile
+++ b/tools/lib/api/Makefile
@@ -60,7 +60,7 @@ $(LIBFILE): $(API_IN)
 
 clean:
 	$(call QUIET_CLEAN, libapi) $(RM) $(LIBFILE); \
-	find $(if $(OUTPUT),$(OUTPUT),.) -name \*.o -or -name \*.o.cmd -or -name \*.o.d | xargs $(RM)
+	find $(or $(OUTPUT),.) -name \*.o -or -name \*.o.cmd -or -name \*.o.d | xargs $(RM)
 
 FORCE:
 
diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index f947b61b2107..36b85aea0393 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -60,7 +60,7 @@ ifndef VERBOSE
   VERBOSE = 0
 endif
 
-INCLUDES = -I$(if $(OUTPUT),$(OUTPUT),.)				\
+INCLUDES = -I$(or $(OUTPUT),.) \
 	   -I$(srctree)/tools/include -I$(srctree)/tools/include/uapi
 
 export prefix libdir src obj
diff --git a/tools/lib/perf/Makefile b/tools/lib/perf/Makefile
index 08fe6e3c4089..21df023a2103 100644
--- a/tools/lib/perf/Makefile
+++ b/tools/lib/perf/Makefile
@@ -153,7 +153,7 @@ $(TESTS_STATIC): $(TESTS_IN) $(LIBPERF_A) $(LIBAPI)
 	$(QUIET_LINK)$(CC) -o $@ $^
 
 $(TESTS_SHARED): $(TESTS_IN) $(LIBAPI)
-	$(QUIET_LINK)$(CC) -o $@ -L$(if $(OUTPUT),$(OUTPUT),.) $^ -lperf
+	$(QUIET_LINK)$(CC) -o $@ -L$(or $(OUTPUT),.) $^ -lperf
 
 make-tests: libs $(TESTS_SHARED) $(TESTS_STATIC)
 
diff --git a/tools/lib/subcmd/Makefile b/tools/lib/subcmd/Makefile
index 1c777a72bb39..8f1a09cdfd17 100644
--- a/tools/lib/subcmd/Makefile
+++ b/tools/lib/subcmd/Makefile
@@ -63,7 +63,7 @@ $(LIBFILE): $(SUBCMD_IN)
 
 clean:
 	$(call QUIET_CLEAN, libsubcmd) $(RM) $(LIBFILE); \
-	find $(if $(OUTPUT),$(OUTPUT),.) -name \*.o -or -name \*.o.cmd -or -name \*.o.d | xargs $(RM)
+	find $(or $(OUTPUT),.) -name \*.o -or -name \*.o.cmd -or -name \*.o.d | xargs $(RM)
 
 FORCE:
 
diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index 92ce4fce7bc7..0dbd397f319d 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -13,7 +13,7 @@ srctree := $(patsubst %/,%,$(dir $(srctree)))
 endif
 
 SUBCMD_SRCDIR		= $(srctree)/tools/lib/subcmd/
-LIBSUBCMD_OUTPUT	= $(if $(OUTPUT),$(OUTPUT),$(CURDIR)/)
+LIBSUBCMD_OUTPUT	= $(or $(OUTPUT),$(CURDIR)/)
 LIBSUBCMD		= $(LIBSUBCMD_OUTPUT)libsubcmd.a
 
 OBJTOOL    := $(OUTPUT)objtool
diff --git a/tools/pci/Makefile b/tools/pci/Makefile
index 4b95a5176355..57744778b518 100644
--- a/tools/pci/Makefile
+++ b/tools/pci/Makefile
@@ -42,7 +42,7 @@ $(OUTPUT)pcitest: $(PCITEST_IN)
 clean:
 	rm -f $(ALL_PROGRAMS)
 	rm -rf $(OUTPUT)include/
-	find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
+	find $(or $(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
 
 install: $(ALL_PROGRAMS)
 	install -d -m 755 $(DESTDIR)$(bindir);		\
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index ac861e42c8f7..8583d18a3739 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -724,7 +724,7 @@ endif
 # get relative building directory (to $(OUTPUT))
 # and '.' if it's $(OUTPUT) itself
 __build-dir = $(subst $(OUTPUT),,$(dir $@))
-build-dir   = $(if $(__build-dir),$(__build-dir),.)
+build-dir   = $(or $(__build-dir),.)
 
 prepare: $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)common-cmds.h archheaders $(drm_ioctl_array) \
 	$(fadvise_advice_array) \
@@ -1090,7 +1090,7 @@ bpf-skel-clean:
 
 clean:: $(LIBTRACEEVENT)-clean $(LIBAPI)-clean $(LIBBPF)-clean $(LIBSUBCMD)-clean $(LIBPERF)-clean fixdep-clean python-clean bpf-skel-clean
 	$(call QUIET_CLEAN, core-objs)  $(RM) $(LIBPERF_A) $(OUTPUT)perf-archive $(OUTPUT)perf-with-kcore $(OUTPUT)perf-iostat $(LANG_BINDINGS)
-	$(Q)find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.cmd' -delete -o -name '\.*.d' -delete
+	$(Q)find $(or $(OUTPUT),.) -name '*.o' -delete -o -name '\.*.cmd' -delete -o -name '\.*.d' -delete
 	$(Q)$(RM) $(OUTPUT).config-detected
 	$(call QUIET_CLEAN, core-progs) $(RM) $(ALL_PROGRAMS) perf perf-read-vdso32 perf-read-vdsox32 $(OUTPUT)pmu-events/jevents $(OUTPUT)$(LIBJVMTI).so
 	$(call QUIET_CLEAN, core-gen)   $(RM)  *.spec *.pyc *.pyo */*.pyc */*.pyo $(OUTPUT)common-cmds.h TAGS tags cscope* $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)FEATURE-DUMP $(OUTPUT)util/*-bison* $(OUTPUT)util/*-flex* \
diff --git a/tools/power/x86/intel-speed-select/Makefile b/tools/power/x86/intel-speed-select/Makefile
index 12c6939dca2a..7eaa517cd403 100644
--- a/tools/power/x86/intel-speed-select/Makefile
+++ b/tools/power/x86/intel-speed-select/Makefile
@@ -43,7 +43,7 @@ $(OUTPUT)intel-speed-select: $(ISST_IN)
 clean:
 	rm -f $(ALL_PROGRAMS)
 	rm -rf $(OUTPUT)include/linux/isst_if.h
-	find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
+	find $(or $(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
 
 install: $(ALL_PROGRAMS)
 	install -d -m 755 $(DESTDIR)$(bindir);		\
diff --git a/tools/scripts/utilities.mak b/tools/scripts/utilities.mak
index c16ce833079c..172e47273b5d 100644
--- a/tools/scripts/utilities.mak
+++ b/tools/scripts/utilities.mak
@@ -175,5 +175,5 @@ _ge-abspath = $(if $(is-executable),$(1))
 define get-executable-or-default
 $(if $($(1)),$(call _ge_attempt,$($(1)),$(1)),$(call _ge_attempt,$(2)))
 endef
-_ge_attempt = $(if $(get-executable),$(get-executable),$(call _gea_err,$(2)))
+_ge_attempt = $(or $(get-executable),$(call _gea_err,$(2)))
 _gea_err  = $(if $(1),$(error Please set '$(1)' appropriately))
diff --git a/tools/spi/Makefile b/tools/spi/Makefile
index 0aa6dbd31fb8..7fccd245a535 100644
--- a/tools/spi/Makefile
+++ b/tools/spi/Makefile
@@ -53,9 +53,9 @@ $(OUTPUT)spidev_fdx: $(SPIDEV_FDX_IN)
 clean:
 	rm -f $(ALL_PROGRAMS)
 	rm -rf $(OUTPUT)include/
-	find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete
-	find $(if $(OUTPUT),$(OUTPUT),.) -name '\.*.o.d' -delete
-	find $(if $(OUTPUT),$(OUTPUT),.) -name '\.*.o.cmd' -delete
+	find $(or $(OUTPUT),.) -name '*.o' -delete
+	find $(or $(OUTPUT),.) -name '\.*.o.d' -delete
+	find $(or $(OUTPUT),.) -name '\.*.o.cmd' -delete
 
 install: $(ALL_PROGRAMS)
 	install -d -m 755 $(DESTDIR)$(bindir);		\
diff --git a/tools/tracing/rtla/Makefile b/tools/tracing/rtla/Makefile
index 5a1eda617992..11fb417abb42 100644
--- a/tools/tracing/rtla/Makefile
+++ b/tools/tracing/rtla/Makefile
@@ -46,7 +46,7 @@ DATADIR	:=	/usr/share
 DOCDIR	:=	$(DATADIR)/doc
 MANDIR	:=	$(DATADIR)/man
 LICDIR	:=	$(DATADIR)/licenses
-SRCTREE	:=	$(if $(BUILD_SRC),$(BUILD_SRC),$(CURDIR))
+SRCTREE	:=	$(or $(BUILD_SRC),$(CURDIR))
 
 # If running from the tarball, man pages are stored in the Documentation
 # dir. If running from the kernel source, man pages are stored in
diff --git a/tools/usb/Makefile b/tools/usb/Makefile
index 1b128e551b2e..c6235667dd46 100644
--- a/tools/usb/Makefile
+++ b/tools/usb/Makefile
@@ -38,7 +38,7 @@ $(OUTPUT)ffs-test: $(FFS_TEST_IN)
 
 clean:
 	rm -f $(ALL_PROGRAMS)
-	find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete -o -name '\.*.o.cmd' -delete
+	find $(or $(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete -o -name '\.*.o.cmd' -delete
 
 install: $(ALL_PROGRAMS)
 	install -d -m 755 $(DESTDIR)$(bindir);		\

From 868653f421cd37e8ec3880da19f0aac93f5c46cc Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Sun, 13 Feb 2022 01:18:37 +0900
Subject: [PATCH 04/13] kconfig: add fflush() before ferror() check

As David Laight pointed out, there is not much point in calling
ferror() unless you call fflush() first.

Reported-by: David Laight <David.Laight@ACULAB.COM>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
 scripts/kconfig/confdata.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index d3c3a61308ad..94dcec2cc803 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -979,6 +979,7 @@ static int conf_write_autoconf_cmd(const char *autoconf_name)
 
 	fprintf(out, "\n$(deps_config): ;\n");
 
+	fflush(out);
 	ret = ferror(out); /* error check for all fprintf() calls */
 	fclose(out);
 	if (ret)
@@ -1097,6 +1098,7 @@ static int __conf_write_autoconf(const char *filename,
 		if ((sym->flags & SYMBOL_WRITE) && sym->name)
 			print_symbol(file, sym);
 
+	fflush(file);
 	/* check possible errors in conf_write_heading() and print_symbol() */
 	ret = ferror(file);
 	fclose(file);

From a7d4f58e99dd3f6067606115ce147c15c17b6e93 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Mon, 14 Feb 2022 12:19:18 +0900
Subject: [PATCH 05/13] kconfig: fix missing '# end of' for empty menu

Currently, "# end of ..." is inserted when the menu goes back to its
parent.

Hence, an empty menu:

  menu "Foo"
  endmenu

... ends up with unbalanced menu comments, like this:

  #
  # Foo
  #

Let's close the menu comments properly:

  #
  # Foo
  #
  # end of Foo

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
 scripts/kconfig/confdata.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index 94dcec2cc803..901835a56e89 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -903,19 +903,20 @@ next:
 			menu = menu->list;
 			continue;
 		}
-		if (menu->next)
+
+end_check:
+		if (!menu->sym && menu_is_visible(menu) && menu != &rootmenu &&
+		    menu->prompt->type == P_MENU) {
+			fprintf(out, "# end of %s\n", menu_get_prompt(menu));
+			need_newline = true;
+		}
+
+		if (menu->next) {
 			menu = menu->next;
-		else while ((menu = menu->parent)) {
-			if (!menu->sym && menu_is_visible(menu) &&
-			    menu != &rootmenu) {
-				str = menu_get_prompt(menu);
-				fprintf(out, "# end of %s\n", str);
-				need_newline = true;
-			}
-			if (menu->next) {
-				menu = menu->next;
-				break;
-			}
+		} else {
+			menu = menu->parent;
+			if (menu)
+				goto end_check;
 		}
 	}
 	fclose(out);

From d4c858643263cfde13f7d937eaff95c2ed87cdf1 Mon Sep 17 00:00:00 2001
From: Changbin Du <changbin.du@gmail.com>
Date: Tue, 1 Feb 2022 09:32:57 +0800
Subject: [PATCH 06/13] kallsyms: ignore all local labels prefixed by '.L'

The llvm compiler can generate lots of local labels ('.LBB', '.Ltmpxxx',
'.L__unnamed_xx', etc.). These symbols usually are useless for debugging.
And they might overlap with handwritten symbols.

Before this change, a dumpstack shows a local symbol for epc:
[    0.040341][    T0] Hardware name: riscv-virtio,qemu (DT)
[    0.040376][    T0] epc : .LBB6_14+0x22/0x6a
[    0.040452][    T0]  ra : restore_all+0x12/0x6e

The simple solution is that we can ignore all local labels prefixed by '.L'.
For handwritten symbols which need to be preserved should drop the '.L'
prefix.

After this change, the C defined symbol is shown so we can locate the
problematical code immediately:
[    0.035795][    T0] Hardware name: riscv-virtio,qemu (DT)
[    0.036332][    T0] epc : trace_hardirqs_on+0x54/0x13c
[    0.036567][    T0]  ra : restore_all+0x12/0x6e

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
 scripts/kallsyms.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 54ad86d13784..8caabddf817c 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -108,7 +108,7 @@ static bool is_ignored_symbol(const char *name, char type)
 	/* Symbol names that begin with the following are ignored.*/
 	static const char * const ignored_prefixes[] = {
 		"$",			/* local symbols for ARM, MIPS, etc. */
-		".LASANPC",		/* s390 kasan local symbols */
+		".L",			/* local labels, .LBB,.Ltmpxxx,.L__unnamed_xx,.LASANPC, etc. */
 		"__crc_",		/* modversions */
 		"__efistub_",		/* arm64 EFI stub namespace */
 		"__kvm_nvhe_",		/* arm64 non-VHE KVM namespace */

From 6ce019f73d52513239314e75376a5ca622aa3632 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Fri, 18 Feb 2022 13:46:33 +0900
Subject: [PATCH 07/13] certs: include certs/signing_key.x509 unconditionally

I do not see much sense in the #if conditional in system_certificates.S;
even if the condition is true, there exists no signing key when
CONFIG_MODULE_SIG_KEY="".

So, certs/Makefile generates empty certs/signing_key.x509 in such a
case. We can always do this, irrespective of CONFIG_MODULE_SIG or
(CONFIG_IMA_APPRAISE_MODSIG && CONFIG_MODULES).

We only need to check CONFIG_MODULE_SIG_KEY, then both *.S and Makefile
will become much simpler.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
 certs/Makefile              | 16 ----------------
 certs/system_certificates.S |  3 ---
 2 files changed, 19 deletions(-)

diff --git a/certs/Makefile b/certs/Makefile
index 3ea7fe60823f..68c1d7b9a388 100644
--- a/certs/Makefile
+++ b/certs/Makefile
@@ -22,25 +22,10 @@ $(obj)/x509_certificate_list: $(CONFIG_SYSTEM_TRUSTED_KEYS) $(obj)/extract-cert
 
 targets += x509_certificate_list
 
-ifeq ($(CONFIG_MODULE_SIG),y)
-	SIGN_KEY = y
-endif
-
-ifeq ($(CONFIG_IMA_APPRAISE_MODSIG),y)
-ifeq ($(CONFIG_MODULES),y)
-	SIGN_KEY = y
-endif
-endif
-
-ifdef SIGN_KEY
-###############################################################################
-#
 # If module signing is requested, say by allyesconfig, but a key has not been
 # supplied, then one will need to be generated to make sure the build does not
 # fail and that the kernel may be used afterwards.
 #
-###############################################################################
-
 # We do it this way rather than having a boolean option for enabling an
 # external private key, because 'make randconfig' might enable such a
 # boolean option and we unfortunately can't make it depend on !RANDCONFIG.
@@ -76,7 +61,6 @@ $(obj)/system_certificates.o: $(obj)/signing_key.x509
 
 $(obj)/signing_key.x509: $(X509_DEP) $(obj)/extract-cert FORCE
 	$(call if_changed,extract_certs,$(if $(CONFIG_MODULE_SIG_KEY),$(if $(X509_DEP),$<,$(CONFIG_MODULE_SIG_KEY)),""))
-endif # CONFIG_MODULE_SIG
 
 targets += signing_key.x509
 
diff --git a/certs/system_certificates.S b/certs/system_certificates.S
index e1645e6f4d97..003e25d4a17e 100644
--- a/certs/system_certificates.S
+++ b/certs/system_certificates.S
@@ -9,10 +9,7 @@
 system_certificate_list:
 __cert_list_start:
 __module_cert_start:
-#if defined(CONFIG_MODULE_SIG) || (defined(CONFIG_IMA_APPRAISE_MODSIG) \
-			       && defined(CONFIG_MODULES))
 	.incbin "certs/signing_key.x509"
-#endif
 __module_cert_end:
 	.incbin "certs/x509_certificate_list"
 __cert_list_end:

From f44b645fe0070c0f1ac34a358252a7123c56e709 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Fri, 18 Feb 2022 13:46:34 +0900
Subject: [PATCH 08/13] certs: simplify empty certs creation in certs/Makefile

To create an empty cert file, we need to pass "" to the extract-cert
tool, which is common for all the three call-sites of cmd_extract_certs.

Factor out the logic into extract-cert-in.

One exceptional case is PKCS#11 case, where we override extract-cert-in
with the URI.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
---
 certs/Makefile | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/certs/Makefile b/certs/Makefile
index 68c1d7b9a388..d8443cfb1c40 100644
--- a/certs/Makefile
+++ b/certs/Makefile
@@ -13,12 +13,13 @@ obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_nohashes.o
 endif
 
 quiet_cmd_extract_certs  = CERT    $@
-      cmd_extract_certs  = $(obj)/extract-cert $(2) $@
+      cmd_extract_certs  = $(obj)/extract-cert $(extract-cert-in) $@
+extract-cert-in = $(or $(filter-out $(obj)/extract-cert, $(real-prereqs)),"")
 
 $(obj)/system_certificates.o: $(obj)/x509_certificate_list
 
 $(obj)/x509_certificate_list: $(CONFIG_SYSTEM_TRUSTED_KEYS) $(obj)/extract-cert FORCE
-	$(call if_changed,extract_certs,$(if $(CONFIG_SYSTEM_TRUSTED_KEYS),$<,""))
+	$(call if_changed,extract_certs)
 
 targets += x509_certificate_list
 
@@ -52,22 +53,22 @@ $(obj)/x509.genkey:
 
 endif # CONFIG_MODULE_SIG_KEY
 
-# If CONFIG_MODULE_SIG_KEY isn't a PKCS#11 URI, depend on it
-ifneq ($(filter-out pkcs11:%, $(CONFIG_MODULE_SIG_KEY)),)
-X509_DEP := $(CONFIG_MODULE_SIG_KEY)
-endif
-
 $(obj)/system_certificates.o: $(obj)/signing_key.x509
 
-$(obj)/signing_key.x509: $(X509_DEP) $(obj)/extract-cert FORCE
-	$(call if_changed,extract_certs,$(if $(CONFIG_MODULE_SIG_KEY),$(if $(X509_DEP),$<,$(CONFIG_MODULE_SIG_KEY)),""))
+PKCS11_URI := $(filter pkcs11:%, $(CONFIG_MODULE_SIG_KEY))
+ifdef PKCS11_URI
+$(obj)/signing_key.x509: extract-cert-in := $(PKCS11_URI)
+endif
+
+$(obj)/signing_key.x509: $(filter-out $(PKCS11_URI),$(CONFIG_MODULE_SIG_KEY)) $(obj)/extract-cert FORCE
+	$(call if_changed,extract_certs)
 
 targets += signing_key.x509
 
 $(obj)/revocation_certificates.o: $(obj)/x509_revocation_list
 
 $(obj)/x509_revocation_list: $(CONFIG_SYSTEM_REVOCATION_KEYS) $(obj)/extract-cert FORCE
-	$(call if_changed,extract_certs,$(if $(CONFIG_SYSTEM_REVOCATION_KEYS),$<,""))
+	$(call if_changed,extract_certs)
 
 targets += x509_revocation_list
 

From c1ea04d82778ed04ed0943eb85c55c221d9d3a5b Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Sun, 27 Feb 2022 18:03:35 +0900
Subject: [PATCH 09/13] usr/include: replace extra-y with always-y

extra-y is not run for 'make modules'. The header compile test should
be executed irrespective of the build target. always-y is a better fit.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
 usr/include/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/usr/include/Makefile b/usr/include/Makefile
index 5bc0d566cfe0..ac206fb27c65 100644
--- a/usr/include/Makefile
+++ b/usr/include/Makefile
@@ -95,7 +95,7 @@ endif
 # asm-generic/*.h is used by asm/*.h, and should not be included directly
 no-header-test += asm-generic/%
 
-extra-y := $(patsubst $(obj)/%.h,%.hdrtest, $(shell find $(obj) -name '*.h' 2>/dev/null))
+always-y := $(patsubst $(obj)/%.h,%.hdrtest, $(shell find $(obj) -name '*.h' 2>/dev/null))
 
 # Include the header twice to detect missing include guard.
 quiet_cmd_hdrtest = HDRTEST $<

From bbc90bc1bd4a63121bae9cbfafe1e1f0beaf24b1 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Sun, 27 Feb 2022 18:10:24 +0900
Subject: [PATCH 10/13] arch: syscalls: simplify uapi/kapi directory creation

$(shell ...) expands to empty. There is no need to assign it to _dummy.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
 arch/alpha/kernel/syscalls/Makefile      | 3 +--
 arch/arm/tools/Makefile                  | 3 +--
 arch/ia64/kernel/syscalls/Makefile       | 3 +--
 arch/m68k/kernel/syscalls/Makefile       | 3 +--
 arch/microblaze/kernel/syscalls/Makefile | 3 +--
 arch/mips/kernel/syscalls/Makefile       | 3 +--
 arch/parisc/kernel/syscalls/Makefile     | 3 +--
 arch/powerpc/kernel/syscalls/Makefile    | 3 +--
 arch/s390/kernel/syscalls/Makefile       | 3 +--
 arch/sh/kernel/syscalls/Makefile         | 3 +--
 arch/sparc/kernel/syscalls/Makefile      | 3 +--
 arch/x86/entry/syscalls/Makefile         | 3 +--
 arch/xtensa/kernel/syscalls/Makefile     | 3 +--
 13 files changed, 13 insertions(+), 26 deletions(-)

diff --git a/arch/alpha/kernel/syscalls/Makefile b/arch/alpha/kernel/syscalls/Makefile
index 6713c65a25e1..b265e4bc16c2 100644
--- a/arch/alpha/kernel/syscalls/Makefile
+++ b/arch/alpha/kernel/syscalls/Makefile
@@ -2,8 +2,7 @@
 kapi := arch/$(SRCARCH)/include/generated/asm
 uapi := arch/$(SRCARCH)/include/generated/uapi/asm
 
-_dummy := $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)')	\
-	  $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)')
+$(shell mkdir -p $(uapi) $(kapi))
 
 syscall := $(src)/syscall.tbl
 syshdr := $(srctree)/scripts/syscallhdr.sh
diff --git a/arch/arm/tools/Makefile b/arch/arm/tools/Makefile
index 4a5c50f67ced..81f13bdf32f2 100644
--- a/arch/arm/tools/Makefile
+++ b/arch/arm/tools/Makefile
@@ -29,8 +29,7 @@ kapi:	$(kapi-hdrs-y) $(gen-y)
 uapi:	$(uapi-hdrs-y)
 
 # Create output directory if not already present
-_dummy := $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)') \
-          $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)')
+$(shell mkdir -p $(kapi) $(uapi))
 
 quiet_cmd_gen_mach = GEN     $@
       cmd_gen_mach = $(AWK) -f $(real-prereqs) > $@
diff --git a/arch/ia64/kernel/syscalls/Makefile b/arch/ia64/kernel/syscalls/Makefile
index 14f40ecf8b65..d009f927a048 100644
--- a/arch/ia64/kernel/syscalls/Makefile
+++ b/arch/ia64/kernel/syscalls/Makefile
@@ -2,8 +2,7 @@
 kapi := arch/$(SRCARCH)/include/generated/asm
 uapi := arch/$(SRCARCH)/include/generated/uapi/asm
 
-_dummy := $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)')	\
-	  $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)')
+$(shell mkdir -p $(uapi) $(kapi))
 
 syscall := $(src)/syscall.tbl
 syshdr := $(srctree)/scripts/syscallhdr.sh
diff --git a/arch/m68k/kernel/syscalls/Makefile b/arch/m68k/kernel/syscalls/Makefile
index 6713c65a25e1..b265e4bc16c2 100644
--- a/arch/m68k/kernel/syscalls/Makefile
+++ b/arch/m68k/kernel/syscalls/Makefile
@@ -2,8 +2,7 @@
 kapi := arch/$(SRCARCH)/include/generated/asm
 uapi := arch/$(SRCARCH)/include/generated/uapi/asm
 
-_dummy := $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)')	\
-	  $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)')
+$(shell mkdir -p $(uapi) $(kapi))
 
 syscall := $(src)/syscall.tbl
 syshdr := $(srctree)/scripts/syscallhdr.sh
diff --git a/arch/microblaze/kernel/syscalls/Makefile b/arch/microblaze/kernel/syscalls/Makefile
index 6713c65a25e1..b265e4bc16c2 100644
--- a/arch/microblaze/kernel/syscalls/Makefile
+++ b/arch/microblaze/kernel/syscalls/Makefile
@@ -2,8 +2,7 @@
 kapi := arch/$(SRCARCH)/include/generated/asm
 uapi := arch/$(SRCARCH)/include/generated/uapi/asm
 
-_dummy := $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)')	\
-	  $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)')
+$(shell mkdir -p $(uapi) $(kapi))
 
 syscall := $(src)/syscall.tbl
 syshdr := $(srctree)/scripts/syscallhdr.sh
diff --git a/arch/mips/kernel/syscalls/Makefile b/arch/mips/kernel/syscalls/Makefile
index 10bf90dc02c0..e6b21de65cca 100644
--- a/arch/mips/kernel/syscalls/Makefile
+++ b/arch/mips/kernel/syscalls/Makefile
@@ -2,8 +2,7 @@
 kapi := arch/$(SRCARCH)/include/generated/asm
 uapi := arch/$(SRCARCH)/include/generated/uapi/asm
 
-_dummy := $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)')	\
-	  $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)')
+$(shell mkdir -p $(uapi) $(kapi))
 
 syshdr := $(srctree)/scripts/syscallhdr.sh
 sysnr := $(srctree)/$(src)/syscallnr.sh
diff --git a/arch/parisc/kernel/syscalls/Makefile b/arch/parisc/kernel/syscalls/Makefile
index d63f18dd058d..8440c16dfb22 100644
--- a/arch/parisc/kernel/syscalls/Makefile
+++ b/arch/parisc/kernel/syscalls/Makefile
@@ -2,8 +2,7 @@
 kapi := arch/$(SRCARCH)/include/generated/asm
 uapi := arch/$(SRCARCH)/include/generated/uapi/asm
 
-_dummy := $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)')	\
-	  $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)')
+$(shell mkdir -p $(uapi) $(kapi))
 
 syscall := $(src)/syscall.tbl
 syshdr := $(srctree)/scripts/syscallhdr.sh
diff --git a/arch/powerpc/kernel/syscalls/Makefile b/arch/powerpc/kernel/syscalls/Makefile
index 5476f62eb80f..9d7bd81510b8 100644
--- a/arch/powerpc/kernel/syscalls/Makefile
+++ b/arch/powerpc/kernel/syscalls/Makefile
@@ -2,8 +2,7 @@
 kapi := arch/$(SRCARCH)/include/generated/asm
 uapi := arch/$(SRCARCH)/include/generated/uapi/asm
 
-_dummy := $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)')	\
-	  $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)')
+$(shell mkdir -p $(uapi) $(kapi))
 
 syscall := $(src)/syscall.tbl
 syshdr := $(srctree)/scripts/syscallhdr.sh
diff --git a/arch/s390/kernel/syscalls/Makefile b/arch/s390/kernel/syscalls/Makefile
index b98f25029b8e..fb85e797946d 100644
--- a/arch/s390/kernel/syscalls/Makefile
+++ b/arch/s390/kernel/syscalls/Makefile
@@ -21,8 +21,7 @@ uapi:	$(uapi-hdrs-y)
 
 
 # Create output directory if not already present
-_dummy := $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)') \
-	  $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)')
+$(shell mkdir -p $(uapi) $(kapi))
 
 filechk_syshdr = $(CONFIG_SHELL) '$(systbl)' -H -a $(syshdr_abi_$(basetarget)) -f "$2" < $<
 
diff --git a/arch/sh/kernel/syscalls/Makefile b/arch/sh/kernel/syscalls/Makefile
index 6713c65a25e1..b265e4bc16c2 100644
--- a/arch/sh/kernel/syscalls/Makefile
+++ b/arch/sh/kernel/syscalls/Makefile
@@ -2,8 +2,7 @@
 kapi := arch/$(SRCARCH)/include/generated/asm
 uapi := arch/$(SRCARCH)/include/generated/uapi/asm
 
-_dummy := $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)')	\
-	  $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)')
+$(shell mkdir -p $(uapi) $(kapi))
 
 syscall := $(src)/syscall.tbl
 syshdr := $(srctree)/scripts/syscallhdr.sh
diff --git a/arch/sparc/kernel/syscalls/Makefile b/arch/sparc/kernel/syscalls/Makefile
index d63f18dd058d..8440c16dfb22 100644
--- a/arch/sparc/kernel/syscalls/Makefile
+++ b/arch/sparc/kernel/syscalls/Makefile
@@ -2,8 +2,7 @@
 kapi := arch/$(SRCARCH)/include/generated/asm
 uapi := arch/$(SRCARCH)/include/generated/uapi/asm
 
-_dummy := $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)')	\
-	  $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)')
+$(shell mkdir -p $(uapi) $(kapi))
 
 syscall := $(src)/syscall.tbl
 syshdr := $(srctree)/scripts/syscallhdr.sh
diff --git a/arch/x86/entry/syscalls/Makefile b/arch/x86/entry/syscalls/Makefile
index 5b3efed0e4e8..9104039cd8f2 100644
--- a/arch/x86/entry/syscalls/Makefile
+++ b/arch/x86/entry/syscalls/Makefile
@@ -3,8 +3,7 @@ out := arch/$(SRCARCH)/include/generated/asm
 uapi := arch/$(SRCARCH)/include/generated/uapi/asm
 
 # Create output directory if not already present
-_dummy := $(shell [ -d '$(out)' ] || mkdir -p '$(out)') \
-	  $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)')
+$(shell mkdir -p $(out) $(uapi))
 
 syscall32 := $(src)/syscall_32.tbl
 syscall64 := $(src)/syscall_64.tbl
diff --git a/arch/xtensa/kernel/syscalls/Makefile b/arch/xtensa/kernel/syscalls/Makefile
index 6713c65a25e1..b265e4bc16c2 100644
--- a/arch/xtensa/kernel/syscalls/Makefile
+++ b/arch/xtensa/kernel/syscalls/Makefile
@@ -2,8 +2,7 @@
 kapi := arch/$(SRCARCH)/include/generated/asm
 uapi := arch/$(SRCARCH)/include/generated/uapi/asm
 
-_dummy := $(shell [ -d '$(uapi)' ] || mkdir -p '$(uapi)')	\
-	  $(shell [ -d '$(kapi)' ] || mkdir -p '$(kapi)')
+$(shell mkdir -p $(uapi) $(kapi))
 
 syscall := $(src)/syscall.tbl
 syshdr := $(srctree)/scripts/syscallhdr.sh

From 69304379ff036ce8ecf41efc2aeea4b29dd0c43f Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Sun, 6 Mar 2022 16:25:35 +0900
Subject: [PATCH 11/13] fixdep: use fflush() and ferror() to ensure successful
 write to files

Currently, fixdep checks the return value from (v)printf(), but it does
not ensure the complete write to the .cmd file.

printf() just writes data to the internal buffer, which usually succeeds.
(Of course, it may fail for another reason, for example when the file
descriptor is closed, but that is another story.)

When the buffer (4k?) is full, an actual write occurs, and printf() may
really fail. One of typical cases is "No space left on device" when the
disk is full.

The data remaining in the buffer will be pushed out to the file when
the program exits, but we never know if it is successful.

One straight-forward fix would be to add the following code at the end
of the program.

   ret = fflush(stdout);
   if (ret < 0) {
          /* error handling */
   }

However, it is tedious to check the return code in all the call sites
of printf(), fflush(), fclose(), and whatever can cause actual writes
to the end device. Doing that lets the program bail out at the first
failure but is usually not worth the effort.

Instead, let's check the error status from ferror(). This is 'sticky',
so you need to check it just once. You still need to call fflush().

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: David Laight <david.laight@aculab.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
---
 scripts/basic/fixdep.c | 46 +++++++++++++++++-------------------------
 1 file changed, 19 insertions(+), 27 deletions(-)

diff --git a/scripts/basic/fixdep.c b/scripts/basic/fixdep.c
index 44e887cff49b..2328f9a641da 100644
--- a/scripts/basic/fixdep.c
+++ b/scripts/basic/fixdep.c
@@ -105,25 +105,6 @@ static void usage(void)
 	exit(1);
 }
 
-/*
- * In the intended usage of this program, the stdout is redirected to .*.cmd
- * files. The return value of printf() must be checked to catch any error,
- * e.g. "No space left on device".
- */
-static void xprintf(const char *format, ...)
-{
-	va_list ap;
-	int ret;
-
-	va_start(ap, format);
-	ret = vprintf(format, ap);
-	if (ret < 0) {
-		perror("fixdep");
-		exit(1);
-	}
-	va_end(ap);
-}
-
 struct item {
 	struct item	*next;
 	unsigned int	len;
@@ -189,7 +170,7 @@ static void use_config(const char *m, int slen)
 
 	define_config(m, slen, hash);
 	/* Print out a dependency path from a symbol name. */
-	xprintf("    $(wildcard include/config/%.*s) \\\n", slen, m);
+	printf("    $(wildcard include/config/%.*s) \\\n", slen, m);
 }
 
 /* test if s ends in sub */
@@ -318,13 +299,13 @@ static void parse_dep_file(char *m, const char *target)
 				 */
 				if (!saw_any_target) {
 					saw_any_target = 1;
-					xprintf("source_%s := %s\n\n",
-						target, m);
-					xprintf("deps_%s := \\\n", target);
+					printf("source_%s := %s\n\n",
+					       target, m);
+					printf("deps_%s := \\\n", target);
 				}
 				is_first_dep = 0;
 			} else {
-				xprintf("  %s \\\n", m);
+				printf("  %s \\\n", m);
 			}
 
 			buf = read_file(m);
@@ -347,8 +328,8 @@ static void parse_dep_file(char *m, const char *target)
 		exit(1);
 	}
 
-	xprintf("\n%s: $(deps_%s)\n\n", target, target);
-	xprintf("$(deps_%s):\n", target);
+	printf("\n%s: $(deps_%s)\n\n", target, target);
+	printf("$(deps_%s):\n", target);
 }
 
 int main(int argc, char *argv[])
@@ -363,11 +344,22 @@ int main(int argc, char *argv[])
 	target = argv[2];
 	cmdline = argv[3];
 
-	xprintf("cmd_%s := %s\n\n", target, cmdline);
+	printf("cmd_%s := %s\n\n", target, cmdline);
 
 	buf = read_file(depfile);
 	parse_dep_file(buf, target);
 	free(buf);
 
+	fflush(stdout);
+
+	/*
+	 * In the intended usage, the stdout is redirected to .*.cmd files.
+	 * Call ferror() to catch errors such as "No space left on device".
+	 */
+	if (ferror(stdout)) {
+		fprintf(stderr, "fixdep: not all data was written to the output\n");
+		exit(1);
+	}
+
 	return 0;
 }

From 9fbed27a7a1101c926718dfa9b49aff1d04477b5 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Sat, 5 Mar 2022 21:56:05 +0900
Subject: [PATCH 12/13] kbuild: add --target to correctly cross-compile UAPI
 headers with Clang

When you compile-test UAPI headers (CONFIG_UAPI_HEADER_TEST=y) with
Clang, they are currently compiled for the host target (likely x86_64)
regardless of the given ARCH=.

In fact, some exported headers include libc headers. For example,
include/uapi/linux/agpgart.h includes <stdlib.h> after being exported.
The header search paths should match to the target we are compiling
them for.

Pick up the --target triple from KBUILD_CFLAGS in the same ways as
commit 7f58b487e9ff ("kbuild: make Clang build userprogs for target
architecture").

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
---
 usr/include/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/usr/include/Makefile b/usr/include/Makefile
index ac206fb27c65..4215801e1110 100644
--- a/usr/include/Makefile
+++ b/usr/include/Makefile
@@ -10,7 +10,7 @@ UAPI_CFLAGS := -std=c90 -Wall -Werror=implicit-function-declaration
 
 # In theory, we do not care -m32 or -m64 for header compile tests.
 # It is here just because CONFIG_CC_CAN_LINK is tested with -m32 or -m64.
-UAPI_CFLAGS += $(filter -m32 -m64, $(KBUILD_CFLAGS))
+UAPI_CFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CFLAGS))
 
 # USERCFLAGS might contain sysroot location for CC.
 UAPI_CFLAGS += $(USERCFLAGS)

From e9c281928c24dfeb86b11c31b53757b6a127f8aa Mon Sep 17 00:00:00 2001
From: Nathan Chancellor <nathan@kernel.org>
Date: Fri, 4 Mar 2022 10:08:14 -0700
Subject: [PATCH 13/13] kbuild: Make $(LLVM) more flexible

The LLVM make variable allows a developer to quickly switch between the
GNU and LLVM tools. However, it does not handle versioned binaries, such
as the ones shipped by Debian, as LLVM=1 just defines the tool variables
with the unversioned binaries.

There was some discussion during the review of the patch that introduces
LLVM=1 around versioned binaries, ultimately coming to the conclusion
that developers can just add the folder that contains the unversioned
binaries to their PATH, as Debian's versioned suffixed binaries are
really just symlinks to the unversioned binaries in /usr/lib/llvm-#/bin:

$ realpath /usr/bin/clang-14
/usr/lib/llvm-14/bin/clang

$ PATH=/usr/lib/llvm-14/bin:$PATH make ... LLVM=1

However, that can be cumbersome to developers who are constantly testing
series with different toolchains and versions. It is simple enough to
support these versioned binaries directly in the Kbuild system by
allowing the developer to specify the version suffix with LLVM=, which
is shorter than the above suggestion:

$ make ... LLVM=-14

It does not change the meaning of LLVM=1 (which will continue to use
unversioned binaries) and it does not add too much additional complexity
to the existing $(LLVM) code, while allowing developers to quickly test
their series with different versions of the whole LLVM suite of tools.

Some developers may build LLVM from source but not add the binaries to
their PATH, as they may not want to use that toolchain systemwide.
Support those developers by allowing them to supply the directory that
the LLVM tools are available in, as it is no more complex to support
than the version suffix change above.

$ make ... LLVM=/path/to/llvm/

Update and reorder the documentation to reflect these new additions.
At the same time, notate that LLVM=0 is not the same as just omitting it
altogether, which has confused people in the past.

Link: https://lore.kernel.org/r/20200317215515.226917-1-ndesaulniers@google.com/
Link: https://lore.kernel.org/r/20220224151322.072632223@infradead.org/
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
 Documentation/kbuild/llvm.rst  | 31 +++++++++++++++++++++++++------
 Makefile                       | 26 ++++++++++++++++----------
 tools/scripts/Makefile.include | 22 ++++++++++++++--------
 tools/testing/selftests/lib.mk |  8 +++++++-
 4 files changed, 62 insertions(+), 25 deletions(-)

diff --git a/Documentation/kbuild/llvm.rst b/Documentation/kbuild/llvm.rst
index d32616891dcf..b854bb413164 100644
--- a/Documentation/kbuild/llvm.rst
+++ b/Documentation/kbuild/llvm.rst
@@ -49,17 +49,36 @@ example: ::
 LLVM Utilities
 --------------
 
-LLVM has substitutes for GNU binutils utilities. Kbuild supports ``LLVM=1``
-to enable them. ::
-
-	make LLVM=1
-
-They can be enabled individually. The full list of the parameters: ::
+LLVM has substitutes for GNU binutils utilities. They can be enabled individually.
+The full list of supported make variables::
 
 	make CC=clang LD=ld.lld AR=llvm-ar NM=llvm-nm STRIP=llvm-strip \
 	  OBJCOPY=llvm-objcopy OBJDUMP=llvm-objdump READELF=llvm-readelf \
 	  HOSTCC=clang HOSTCXX=clang++ HOSTAR=llvm-ar HOSTLD=ld.lld
 
+To simplify the above command, Kbuild supports the ``LLVM`` variable::
+
+	make LLVM=1
+
+If your LLVM tools are not available in your PATH, you can supply their
+location using the LLVM variable with a trailing slash::
+
+	make LLVM=/path/to/llvm/
+
+which will use ``/path/to/llvm/clang``, ``/path/to/llvm/ld.lld``, etc.
+
+If your LLVM tools have a version suffix and you want to test with that
+explicit version rather than the unsuffixed executables like ``LLVM=1``, you
+can pass the suffix using the ``LLVM`` variable::
+
+	make LLVM=-14
+
+which will use ``clang-14``, ``ld.lld-14``, etc.
+
+``LLVM=0`` is not the same as omitting ``LLVM`` altogether, it will behave like
+``LLVM=1``. If you only wish to use certain LLVM utilities, use their respective
+make variables.
+
 The integrated assembler is enabled by default. You can pass ``LLVM_IAS=0`` to
 disable it.
 
diff --git a/Makefile b/Makefile
index a82095c69fdd..b3fb32fd3906 100644
--- a/Makefile
+++ b/Makefile
@@ -424,8 +424,14 @@ HOST_LFS_LDFLAGS := $(shell getconf LFS_LDFLAGS 2>/dev/null)
 HOST_LFS_LIBS := $(shell getconf LFS_LIBS 2>/dev/null)
 
 ifneq ($(LLVM),)
-HOSTCC	= clang
-HOSTCXX	= clang++
+ifneq ($(filter %/,$(LLVM)),)
+LLVM_PREFIX := $(LLVM)
+else ifneq ($(filter -%,$(LLVM)),)
+LLVM_SUFFIX := $(LLVM)
+endif
+
+HOSTCC	= $(LLVM_PREFIX)clang$(LLVM_SUFFIX)
+HOSTCXX	= $(LLVM_PREFIX)clang++$(LLVM_SUFFIX)
 else
 HOSTCC	= gcc
 HOSTCXX	= g++
@@ -444,14 +450,14 @@ KBUILD_HOSTLDLIBS   := $(HOST_LFS_LIBS) $(HOSTLDLIBS)
 # Make variables (CC, etc...)
 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
-STRIP		= llvm-strip
+CC		= $(LLVM_PREFIX)clang$(LLVM_SUFFIX)
+LD		= $(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX)
+AR		= $(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX)
+NM		= $(LLVM_PREFIX)llvm-nm$(LLVM_SUFFIX)
+OBJCOPY		= $(LLVM_PREFIX)llvm-objcopy$(LLVM_SUFFIX)
+OBJDUMP		= $(LLVM_PREFIX)llvm-objdump$(LLVM_SUFFIX)
+READELF		= $(LLVM_PREFIX)llvm-readelf$(LLVM_SUFFIX)
+STRIP		= $(LLVM_PREFIX)llvm-strip$(LLVM_SUFFIX)
 else
 CC		= $(CROSS_COMPILE)gcc
 LD		= $(CROSS_COMPILE)ld
diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include
index 79d102304470..b507a6a733f5 100644
--- a/tools/scripts/Makefile.include
+++ b/tools/scripts/Makefile.include
@@ -52,11 +52,17 @@ define allow-override
 endef
 
 ifneq ($(LLVM),)
-$(call allow-override,CC,clang)
-$(call allow-override,AR,llvm-ar)
-$(call allow-override,LD,ld.lld)
-$(call allow-override,CXX,clang++)
-$(call allow-override,STRIP,llvm-strip)
+ifneq ($(filter %/,$(LLVM)),)
+LLVM_PREFIX := $(LLVM)
+else ifneq ($(filter -%,$(LLVM)),)
+LLVM_SUFFIX := $(LLVM)
+endif
+
+$(call allow-override,CC,$(LLVM_PREFIX)clang$(LLVM_SUFFIX))
+$(call allow-override,AR,$(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX))
+$(call allow-override,LD,$(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX))
+$(call allow-override,CXX,$(LLVM_PREFIX)clang++$(LLVM_SUFFIX))
+$(call allow-override,STRIP,$(LLVM_PREFIX)llvm-strip$(LLVM_SUFFIX))
 else
 # Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix.
 $(call allow-override,CC,$(CROSS_COMPILE)gcc)
@@ -69,9 +75,9 @@ endif
 CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)
 
 ifneq ($(LLVM),)
-HOSTAR  ?= llvm-ar
-HOSTCC  ?= clang
-HOSTLD  ?= ld.lld
+HOSTAR  ?= $(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX)
+HOSTCC  ?= $(LLVM_PREFIX)clang$(LLVM_SUFFIX)
+HOSTLD  ?= $(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX)
 else
 HOSTAR  ?= ar
 HOSTCC  ?= gcc
diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
index a40add31a2e3..2a2d240cdc1b 100644
--- a/tools/testing/selftests/lib.mk
+++ b/tools/testing/selftests/lib.mk
@@ -1,7 +1,13 @@
 # This mimics the top-level Makefile. We do it explicitly here so that this
 # Makefile can operate with or without the kbuild infrastructure.
 ifneq ($(LLVM),)
-CC := clang
+ifneq ($(filter %/,$(LLVM)),)
+LLVM_PREFIX := $(LLVM)
+else ifneq ($(filter -%,$(LLVM)),)
+LLVM_SUFFIX := $(LLVM)
+endif
+
+CC := $(LLVM_PREFIX)clang$(LLVM_SUFFIX)
 else
 CC := $(CROSS_COMPILE)gcc
 endif