From 88b61e3bff93f99712718db785b4aa0c1165f35c Mon Sep 17 00:00:00 2001
From: Nick Desaulniers <ndesaulniers@google.com>
Date: Mon, 19 Sep 2022 10:08:28 -0700
Subject: Makefile.compiler: replace cc-ifversion with compiler-specific macros

cc-ifversion is GCC specific. Replace it with compiler specific
variants. Update the users of cc-ifversion to use these new macros.

Link: https://github.com/ClangBuiltLinux/linux/issues/350
Link: https://lore.kernel.org/llvm/CAGG=3QWSAUakO42kubrCap8fp-gm1ERJJAYXTnP1iHk_wrH=BQ@mail.gmail.com/
Suggested-by: Bill Wendling <morbo@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
 Documentation/kbuild/makefiles.rst | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

(limited to 'Documentation/kbuild/makefiles.rst')

diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
index 11a296e52d68..ee7e3ea1fbe1 100644
--- a/Documentation/kbuild/makefiles.rst
+++ b/Documentation/kbuild/makefiles.rst
@@ -682,22 +682,27 @@ more details, with real examples.
 	In the above example, -Wno-unused-but-set-variable will be added to
 	KBUILD_CFLAGS only if gcc really accepts it.
 
-    cc-ifversion
-	cc-ifversion tests the version of $(CC) and equals the fourth parameter
-	if version expression is true, or the fifth (if given) if the version
-	expression is false.
+    gcc-min-version
+	gcc-min-version tests if the value of $(CONFIG_GCC_VERSION) is greater than
+	or equal to the provided value and evaluates to y if so.
 
 	Example::
 
-		#fs/reiserfs/Makefile
-		ccflags-y := $(call cc-ifversion, -lt, 0402, -O1)
+		cflags-$(call gcc-min-version, 70100) := -foo
 
-	In this example, ccflags-y will be assigned the value -O1 if the
-	$(CC) version is less than 4.2.
-	cc-ifversion takes all the shell operators:
-	-eq, -ne, -lt, -le, -gt, and -ge
-	The third parameter may be a text as in this example, but it may also
-	be an expanded variable or a macro.
+	In this example, cflags-y will be assigned the value -foo if $(CC) is gcc and
+	$(CONFIG_GCC_VERSION) is >= 7.1.
+
+    clang-min-version
+	clang-min-version tests if the value of $(CONFIG_CLANG_VERSION) is greater
+	than or equal to the provided value and evaluates to y if so.
+
+	Example::
+
+		cflags-$(call clang-min-version, 110000) := -foo
+
+	In this example, cflags-y will be assigned the value -foo if $(CC) is clang
+	and $(CONFIG_CLANG_VERSION) is >= 11.0.0.
 
     cc-cross-prefix
 	cc-cross-prefix is used to check if there exists a $(CC) in path with
-- 
cgit v1.2.3


From 3216484550610470013b7ce1c9ed272da0a74589 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Sun, 25 Sep 2022 03:19:14 +0900
Subject: kbuild: use obj-y instead extra-y for objects placed at the head

The objects placed at the head of vmlinux need special treatments:

 - arch/$(SRCARCH)/Makefile adds them to head-y in order to place
   them before other archives in the linker command line.

 - arch/$(SRCARCH)/kernel/Makefile adds them to extra-y instead of
   obj-y to avoid them going into built-in.a.

This commit gets rid of the latter.

Create vmlinux.a to collect all the objects that are unconditionally
linked to vmlinux. The objects listed in head-y are moved to the head
of vmlinux.a by using 'ar m'.

With this, arch/$(SRCARCH)/kernel/Makefile can consistently use obj-y
for builtin objects.

There is no *.o that is directly linked to vmlinux. Drop unneeded code
in scripts/clang-tools/gen_compile_commands.py.

$(AR) mPi needs 'T' to workaround the llvm-ar bug. The fix was suggested
by Nathan Chancellor [1].

[1]: https://lore.kernel.org/llvm/YyjjT5gQ2hGMH0ni@dev-arch.thelio-3990X/

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
---
 Documentation/kbuild/makefiles.rst          | 18 +-----------------
 Makefile                                    | 23 ++++++++++++++++++-----
 arch/alpha/kernel/Makefile                  |  4 ++--
 arch/arc/kernel/Makefile                    |  4 ++--
 arch/arm/kernel/Makefile                    |  4 ++--
 arch/arm64/kernel/Makefile                  |  4 ++--
 arch/csky/kernel/Makefile                   |  4 ++--
 arch/hexagon/kernel/Makefile                |  3 ++-
 arch/ia64/kernel/Makefile                   |  4 ++--
 arch/loongarch/kernel/Makefile              |  4 ++--
 arch/m68k/68000/Makefile                    |  2 +-
 arch/m68k/coldfire/Makefile                 |  2 +-
 arch/m68k/kernel/Makefile                   | 23 ++++++++++++-----------
 arch/microblaze/kernel/Makefile             |  4 ++--
 arch/mips/kernel/Makefile                   |  4 ++--
 arch/nios2/kernel/Makefile                  |  2 +-
 arch/openrisc/kernel/Makefile               |  4 ++--
 arch/parisc/kernel/Makefile                 |  4 ++--
 arch/powerpc/kernel/Makefile                | 20 ++++++++++----------
 arch/riscv/kernel/Makefile                  |  2 +-
 arch/s390/kernel/Makefile                   |  4 ++--
 arch/sh/kernel/Makefile                     |  4 ++--
 arch/sparc/kernel/Makefile                  |  3 +--
 arch/x86/kernel/Makefile                    | 10 +++++-----
 arch/xtensa/kernel/Makefile                 |  4 ++--
 scripts/Makefile.modpost                    |  5 ++---
 scripts/Makefile.vmlinux_o                  |  6 +++---
 scripts/clang-tools/gen_compile_commands.py | 19 +------------------
 scripts/link-vmlinux.sh                     | 10 ++++------
 29 files changed, 91 insertions(+), 113 deletions(-)

(limited to 'Documentation/kbuild/makefiles.rst')

diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
index ee7e3ea1fbe1..5a6a8426cc97 100644
--- a/Documentation/kbuild/makefiles.rst
+++ b/Documentation/kbuild/makefiles.rst
@@ -340,19 +340,7 @@ more details, with real examples.
 
 	Examples are:
 
-	1) head objects
-
-	    Some objects must be placed at the head of vmlinux. They are
-	    directly linked to vmlinux without going through built-in.a
-	    A typical use-case is an object that contains the entry point.
-
-	    arch/$(SRCARCH)/Makefile should specify such objects as head-y.
-
-	    Discussion:
-	      Given that we can control the section order in the linker script,
-	      why do we need head-y?
-
-	2) vmlinux linker script
+	1) vmlinux linker script
 
 	    The linker script for vmlinux is located at
 	    arch/$(SRCARCH)/kernel/vmlinux.lds
@@ -360,10 +348,6 @@ more details, with real examples.
 	Example::
 
 		# arch/x86/kernel/Makefile
-		extra-y	:= head_$(BITS).o
-		extra-y	+= head$(BITS).o
-		extra-y	+= ebda.o
-		extra-y	+= platform-quirks.o
 		extra-y	+= vmlinux.lds
 
 	$(extra-y) should only contain targets needed for vmlinux.
diff --git a/Makefile b/Makefile
index 22a956b9ffe4..8da45f76ec31 100644
--- a/Makefile
+++ b/Makefile
@@ -645,6 +645,8 @@ else
 __all: modules
 endif
 
+targets :=
+
 # Decide whether to build built-in, modular, or both.
 # Normally, just do built-in.
 
@@ -1107,7 +1109,7 @@ export ARCH_LIB		:= $(filter %/, $(libs-y))
 export ARCH_DRIVERS	:= $(drivers-y) $(drivers-m)
 # Externally visible symbols (used by link-vmlinux.sh)
 
-KBUILD_VMLINUX_OBJS := $(head-y) ./built-in.a
+KBUILD_VMLINUX_OBJS := ./built-in.a
 ifdef CONFIG_MODULES
 KBUILD_VMLINUX_OBJS += $(patsubst %/, %/lib.a, $(filter %/, $(libs-y)))
 KBUILD_VMLINUX_LIBS := $(filter-out %/, $(libs-y))
@@ -1115,7 +1117,7 @@ else
 KBUILD_VMLINUX_LIBS := $(patsubst %/,%/lib.a, $(libs-y))
 endif
 
-export KBUILD_VMLINUX_OBJS KBUILD_VMLINUX_LIBS
+export KBUILD_VMLINUX_LIBS
 export KBUILD_LDS          := arch/$(SRCARCH)/kernel/vmlinux.lds
 
 # Recurse until adjust_autoksyms.sh is satisfied
@@ -1140,7 +1142,18 @@ quiet_cmd_autoksyms_h = GEN     $@
 $(autoksyms_h):
 	$(call cmd,autoksyms_h)
 
-vmlinux.o: autoksyms_recursive $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
+# '$(AR) mPi' needs 'T' to workaround the bug of llvm-ar <= 14
+quiet_cmd_ar_vmlinux.a = AR      $@
+      cmd_ar_vmlinux.a = \
+	rm -f $@; \
+	$(AR) cDPrST $@ $(KBUILD_VMLINUX_OBJS); \
+	$(AR) mPiT $$($(AR) t $@ | head -n1) $@ $(head-y)
+
+targets += vmlinux.a
+vmlinux.a: $(KBUILD_VMLINUX_OBJS) autoksyms_recursive FORCE
+	$(call if_changed,ar_vmlinux.a)
+
+vmlinux.o: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.vmlinux_o
 
 ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
@@ -1153,7 +1166,7 @@ cmd_link-vmlinux =                                                 \
 vmlinux: scripts/link-vmlinux.sh vmlinux.o $(KBUILD_LDS) modpost FORCE
 	+$(call if_changed_dep,link-vmlinux)
 
-targets := vmlinux
+targets += vmlinux
 
 # The actual objects are generated when descending,
 # make sure no implicit rule kicks in
@@ -1878,7 +1891,7 @@ quiet_cmd_gen_compile_commands = GEN     $@
       cmd_gen_compile_commands = $(PYTHON3) $< -a $(AR) -o $@ $(filter-out $<, $(real-prereqs))
 
 $(extmod_prefix)compile_commands.json: scripts/clang-tools/gen_compile_commands.py \
-	$(if $(KBUILD_EXTMOD),,$(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)) \
+	$(if $(KBUILD_EXTMOD),, vmlinux.a $(KBUILD_VMLINUX_LIBS)) \
 	$(if $(CONFIG_MODULES), $(MODORDER)) FORCE
 	$(call if_changed,gen_compile_commands)
 
diff --git a/arch/alpha/kernel/Makefile b/arch/alpha/kernel/Makefile
index 5a74581bf0ee..5a5b0a8b7c6a 100644
--- a/arch/alpha/kernel/Makefile
+++ b/arch/alpha/kernel/Makefile
@@ -3,11 +3,11 @@
 # Makefile for the linux kernel.
 #
 
-extra-y		:= head.o vmlinux.lds
+extra-y		:= vmlinux.lds
 asflags-y	:= $(KBUILD_CFLAGS)
 ccflags-y	:= -Wno-sign-compare
 
-obj-y    := entry.o traps.o process.o osf_sys.o irq.o \
+obj-y    := head.o entry.o traps.o process.o osf_sys.o irq.o \
 	    irq_alpha.o signal.o setup.o ptrace.o time.o \
 	    systbls.o err_common.o io.o bugs.o
 
diff --git a/arch/arc/kernel/Makefile b/arch/arc/kernel/Makefile
index 8c4fc4b54c14..0723d888ac44 100644
--- a/arch/arc/kernel/Makefile
+++ b/arch/arc/kernel/Makefile
@@ -3,7 +3,7 @@
 # Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
 #
 
-obj-y	:= arcksyms.o setup.o irq.o reset.o ptrace.o process.o devtree.o
+obj-y	:= head.o arcksyms.o setup.o irq.o reset.o ptrace.o process.o devtree.o
 obj-y	+= signal.o traps.o sys.o troubleshoot.o stacktrace.o disasm.o
 obj-$(CONFIG_ISA_ARCOMPACT)		+= entry-compact.o intc-compact.o
 obj-$(CONFIG_ISA_ARCV2)			+= entry-arcv2.o intc-arcv2.o
@@ -31,4 +31,4 @@ else
 obj-y += ctx_sw_asm.o
 endif
 
-extra-y := vmlinux.lds head.o
+extra-y := vmlinux.lds
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 553866751e1a..8feaa3217ec5 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -89,7 +89,7 @@ obj-$(CONFIG_VDSO)		+= vdso.o
 obj-$(CONFIG_EFI)		+= efi.o
 obj-$(CONFIG_PARAVIRT)	+= paravirt.o
 
-head-y			:= head$(MMUEXT).o
+obj-y			+= head$(MMUEXT).o
 obj-$(CONFIG_DEBUG_LL)	+= debug.o
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 obj-$(CONFIG_ARM_PATCH_PHYS_VIRT)	+= phys2virt.o
@@ -109,4 +109,4 @@ obj-$(CONFIG_HAVE_ARM_SMCCC)	+= smccc-call.o
 
 obj-$(CONFIG_GENERIC_CPU_VULNERABILITIES) += spectre.o
 
-extra-y := $(head-y) vmlinux.lds
+extra-y := vmlinux.lds
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 1add7b01efa7..b619ff207a57 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -85,8 +85,8 @@ $(obj)/vdso-wrap.o: $(obj)/vdso/vdso.so
 $(obj)/vdso32-wrap.o: $(obj)/vdso32/vdso.so
 
 obj-y					+= probes/
-head-y					:= head.o
-extra-y					+= $(head-y) vmlinux.lds
+obj-y					+= head.o
+extra-y					+= vmlinux.lds
 
 ifeq ($(CONFIG_DEBUG_EFI),y)
 AFLAGS_head.o += -DVMLINUX_PATH="\"$(realpath $(objtree)/vmlinux)\""
diff --git a/arch/csky/kernel/Makefile b/arch/csky/kernel/Makefile
index 6f14c924b20d..8a868316b912 100644
--- a/arch/csky/kernel/Makefile
+++ b/arch/csky/kernel/Makefile
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
-extra-y := head.o vmlinux.lds
+extra-y := vmlinux.lds
 
-obj-y += entry.o atomic.o signal.o traps.o irq.o time.o vdso.o vdso/
+obj-y += head.o entry.o atomic.o signal.o traps.o irq.o time.o vdso.o vdso/
 obj-y += power.o syscall.o syscall_table.o setup.o io.o
 obj-y += process.o cpu-probe.o ptrace.o stacktrace.o
 obj-y += probes/
diff --git a/arch/hexagon/kernel/Makefile b/arch/hexagon/kernel/Makefile
index fae3dce32fde..e73cb321630e 100644
--- a/arch/hexagon/kernel/Makefile
+++ b/arch/hexagon/kernel/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
-extra-y := head.o vmlinux.lds
+extra-y := vmlinux.lds
 
+obj-y += head.o
 obj-$(CONFIG_SMP) += smp.o
 
 obj-y += setup.o irq_cpu.o traps.o syscalltab.o signal.o time.o
diff --git a/arch/ia64/kernel/Makefile b/arch/ia64/kernel/Makefile
index 08d4a2ba0652..4a1fcb121dda 100644
--- a/arch/ia64/kernel/Makefile
+++ b/arch/ia64/kernel/Makefile
@@ -7,9 +7,9 @@ ifdef CONFIG_DYNAMIC_FTRACE
 CFLAGS_REMOVE_ftrace.o = -pg
 endif
 
-extra-y	:= head.o vmlinux.lds
+extra-y	:= vmlinux.lds
 
-obj-y := entry.o efi.o efi_stub.o gate-data.o fsys.o irq.o irq_ia64.o	\
+obj-y := head.o entry.o efi.o efi_stub.o gate-data.o fsys.o irq.o irq_ia64.o	\
 	 irq_lsapic.o ivt.o pal.o patch.o process.o ptrace.o sal.o		\
 	 salinfo.o setup.o signal.o sys_ia64.o time.o traps.o unaligned.o \
 	 unwind.o mca.o mca_asm.o topology.o dma-mapping.o iosapic.o acpi.o \
diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index e5be17009fe8..6c33b5c45573 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -3,9 +3,9 @@
 # Makefile for the Linux/LoongArch kernel.
 #
 
-extra-y		:= head.o vmlinux.lds
+extra-y		:= vmlinux.lds
 
-obj-y		+= cpu-probe.o cacheinfo.o env.o setup.o entry.o genex.o \
+obj-y		+= head.o cpu-probe.o cacheinfo.o env.o setup.o entry.o genex.o \
 		   traps.o irq.o idle.o process.o dma.o mem.o io.o reset.o switch.o \
 		   elf.o syscall.o signal.o time.o topology.o inst.o ptrace.o vdso.o
 
diff --git a/arch/m68k/68000/Makefile b/arch/m68k/68000/Makefile
index 674541fdf5b8..279560add577 100644
--- a/arch/m68k/68000/Makefile
+++ b/arch/m68k/68000/Makefile
@@ -17,4 +17,4 @@ obj-$(CONFIG_DRAGEN2)	+= dragen2.o
 obj-$(CONFIG_UCSIMM)	+= ucsimm.o
 obj-$(CONFIG_UCDIMM)	+= ucsimm.o
 
-extra-y 		:= head.o
+obj-y			+= head.o
diff --git a/arch/m68k/coldfire/Makefile b/arch/m68k/coldfire/Makefile
index 9419a6c1f036..c56bc0dc7f2e 100644
--- a/arch/m68k/coldfire/Makefile
+++ b/arch/m68k/coldfire/Makefile
@@ -45,4 +45,4 @@ obj-$(CONFIG_STMARK2)	+= stmark2.o
 obj-$(CONFIG_PCI)	+= pci.o
 
 obj-y			+= gpio.o
-extra-y := head.o
+obj-y			+= head.o
diff --git a/arch/m68k/kernel/Makefile b/arch/m68k/kernel/Makefile
index c0833da6a2ca..af015447dfb4 100644
--- a/arch/m68k/kernel/Makefile
+++ b/arch/m68k/kernel/Makefile
@@ -3,19 +3,20 @@
 # Makefile for the linux kernel.
 #
 
-extra-$(CONFIG_AMIGA)	:= head.o
-extra-$(CONFIG_ATARI)	:= head.o
-extra-$(CONFIG_MAC)	:= head.o
-extra-$(CONFIG_APOLLO)	:= head.o
-extra-$(CONFIG_VME)	:= head.o
-extra-$(CONFIG_HP300)	:= head.o
-extra-$(CONFIG_Q40)	:= head.o
-extra-$(CONFIG_SUN3X)	:= head.o
-extra-$(CONFIG_VIRT)	:= head.o
-extra-$(CONFIG_SUN3)	:= sun3-head.o
 extra-y			+= vmlinux.lds
 
-obj-y	:= entry.o irq.o module.o process.o ptrace.o
+obj-$(CONFIG_AMIGA)	:= head.o
+obj-$(CONFIG_ATARI)	:= head.o
+obj-$(CONFIG_MAC)	:= head.o
+obj-$(CONFIG_APOLLO)	:= head.o
+obj-$(CONFIG_VME)	:= head.o
+obj-$(CONFIG_HP300)	:= head.o
+obj-$(CONFIG_Q40)	:= head.o
+obj-$(CONFIG_SUN3X)	:= head.o
+obj-$(CONFIG_VIRT)	:= head.o
+obj-$(CONFIG_SUN3)	:= sun3-head.o
+
+obj-y	+= entry.o irq.o module.o process.o ptrace.o
 obj-y	+= setup.o signal.o sys_m68k.o syscalltable.o time.o traps.o
 
 obj-$(CONFIG_MMU_MOTOROLA) += ints.o vectors.o
diff --git a/arch/microblaze/kernel/Makefile b/arch/microblaze/kernel/Makefile
index 15a20eb814ce..4393bee64eaf 100644
--- a/arch/microblaze/kernel/Makefile
+++ b/arch/microblaze/kernel/Makefile
@@ -12,9 +12,9 @@ CFLAGS_REMOVE_ftrace.o = -pg
 CFLAGS_REMOVE_process.o = -pg
 endif
 
-extra-y := head.o vmlinux.lds
+extra-y := vmlinux.lds
 
-obj-y += dma.o exceptions.o \
+obj-y += head.o dma.o exceptions.o \
 	hw_exception_handler.o irq.o \
 	process.o prom.o ptrace.o \
 	reset.o setup.o signal.o sys_microblaze.o timer.o traps.o unwind.o
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 7c96282bff2e..5d1addac5e28 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -3,9 +3,9 @@
 # Makefile for the Linux/MIPS kernel.
 #
 
-extra-y		:= head.o vmlinux.lds
+extra-y		:= vmlinux.lds
 
-obj-y		+= branch.o cmpxchg.o elf.o entry.o genex.o idle.o irq.o \
+obj-y		+= head.o branch.o cmpxchg.o elf.o entry.o genex.o idle.o irq.o \
 		   process.o prom.o ptrace.o reset.o setup.o signal.o \
 		   syscall.o time.o topology.o traps.o unaligned.o watch.o \
 		   vdso.o cacheinfo.o
diff --git a/arch/nios2/kernel/Makefile b/arch/nios2/kernel/Makefile
index 0b645e1e3158..78a913181fa1 100644
--- a/arch/nios2/kernel/Makefile
+++ b/arch/nios2/kernel/Makefile
@@ -3,9 +3,9 @@
 # Makefile for the nios2 linux kernel.
 #
 
-extra-y	+= head.o
 extra-y	+= vmlinux.lds
 
+obj-y	+= head.o
 obj-y	+= cpuinfo.o
 obj-y	+= entry.o
 obj-y	+= insnemu.o
diff --git a/arch/openrisc/kernel/Makefile b/arch/openrisc/kernel/Makefile
index 2d172e79f58d..79129161f3e0 100644
--- a/arch/openrisc/kernel/Makefile
+++ b/arch/openrisc/kernel/Makefile
@@ -3,9 +3,9 @@
 # Makefile for the linux kernel.
 #
 
-extra-y	:= head.o vmlinux.lds
+extra-y	:= vmlinux.lds
 
-obj-y	:= setup.o or32_ksyms.o process.o dma.o \
+obj-y	:= head.o setup.o or32_ksyms.o process.o dma.o \
 	   traps.o time.o irq.o entry.o ptrace.o signal.o \
 	   sys_call_table.o unwinder.o
 
diff --git a/arch/parisc/kernel/Makefile b/arch/parisc/kernel/Makefile
index d0bfac89a842..3d138c9cf9ce 100644
--- a/arch/parisc/kernel/Makefile
+++ b/arch/parisc/kernel/Makefile
@@ -3,9 +3,9 @@
 # Makefile for arch/parisc/kernel
 #
 
-extra-y			:= head.o vmlinux.lds
+extra-y		:= vmlinux.lds
 
-obj-y	     	:= cache.o pacache.o setup.o pdt.o traps.o time.o irq.o \
+obj-y		:= head.o cache.o pacache.o setup.o pdt.o traps.o time.o irq.o \
 		   pa7300lc.o syscall.o entry.o sys_parisc.o firmware.o \
 		   ptrace.o hardware.o inventory.o drivers.o alternative.o \
 		   signal.o hpmc.o real2.o parisc_ksyms.o unaligned.o \
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 06d2d1f78f71..ad3decb9f20b 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -118,12 +118,12 @@ obj-$(CONFIG_PPC_FSL_BOOK3E)	+= cpu_setup_fsl_booke.o
 obj-$(CONFIG_PPC_DOORBELL)	+= dbell.o
 obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o
 
-extra-$(CONFIG_PPC64)		:= head_64.o
-extra-$(CONFIG_PPC_BOOK3S_32)	:= head_book3s_32.o
-extra-$(CONFIG_40x)		:= head_40x.o
-extra-$(CONFIG_44x)		:= head_44x.o
-extra-$(CONFIG_FSL_BOOKE)	:= head_fsl_booke.o
-extra-$(CONFIG_PPC_8xx)		:= head_8xx.o
+obj-$(CONFIG_PPC64)		+= head_64.o
+obj-$(CONFIG_PPC_BOOK3S_32)	+= head_book3s_32.o
+obj-$(CONFIG_40x)		+= head_40x.o
+obj-$(CONFIG_44x)		+= head_44x.o
+obj-$(CONFIG_FSL_BOOKE)		+= head_fsl_booke.o
+obj-$(CONFIG_PPC_8xx)		+= head_8xx.o
 extra-y				+= vmlinux.lds
 
 obj-$(CONFIG_RELOCATABLE)	+= reloc_$(BITS).o
@@ -198,10 +198,10 @@ KCOV_INSTRUMENT_paca.o := n
 CFLAGS_setup_64.o		+= -fno-stack-protector
 CFLAGS_paca.o			+= -fno-stack-protector
 
-extra-$(CONFIG_PPC_FPU)		+= fpu.o
-extra-$(CONFIG_ALTIVEC)		+= vector.o
-extra-$(CONFIG_PPC64)		+= entry_64.o
-extra-$(CONFIG_PPC_OF_BOOT_TRAMPOLINE)	+= prom_init.o
+obj-$(CONFIG_PPC_FPU)		+= fpu.o
+obj-$(CONFIG_ALTIVEC)		+= vector.o
+obj-$(CONFIG_PPC64)		+= entry_64.o
+obj-$(CONFIG_PPC_OF_BOOT_TRAMPOLINE)	+= prom_init.o
 
 extra-$(CONFIG_PPC_OF_BOOT_TRAMPOLINE)	+= prom_init_check
 
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index 33bb60a354cd..db6e4b1294ba 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -28,9 +28,9 @@ KASAN_SANITIZE_cpufeature.o := n
 endif
 endif
 
-extra-y += head.o
 extra-y += vmlinux.lds
 
+obj-y	+= head.o
 obj-y	+= soc.o
 obj-$(CONFIG_RISCV_ALTERNATIVE) += alternative.o
 obj-y	+= cpu.o
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index 3cbfa9fddd9a..7ce00816b8df 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -33,7 +33,7 @@ CFLAGS_stacktrace.o	+= -fno-optimize-sibling-calls
 CFLAGS_dumpstack.o	+= -fno-optimize-sibling-calls
 CFLAGS_unwind_bc.o	+= -fno-optimize-sibling-calls
 
-obj-y	:= traps.o time.o process.o earlypgm.o early.o setup.o idle.o vtime.o
+obj-y	:= head64.o traps.o time.o process.o earlypgm.o early.o setup.o idle.o vtime.o
 obj-y	+= processor.o syscall.o ptrace.o signal.o cpcmd.o ebcdic.o nmi.o
 obj-y	+= debug.o irq.o ipl.o dis.o diag.o vdso.o cpufeature.o
 obj-y	+= sysinfo.o lgr.o os_info.o machine_kexec.o
@@ -42,7 +42,7 @@ obj-y	+= entry.o reipl.o relocate_kernel.o kdebugfs.o alternative.o
 obj-y	+= nospec-branch.o ipl_vmparm.o machine_kexec_reloc.o unwind_bc.o
 obj-y	+= smp.o text_amode31.o stacktrace.o
 
-extra-y				+= head64.o vmlinux.lds
+extra-y				+= vmlinux.lds
 
 obj-$(CONFIG_SYSFS)		+= nospec-sysfs.o
 CFLAGS_REMOVE_nospec-branch.o	+= $(CC_FLAGS_EXPOLINE)
diff --git a/arch/sh/kernel/Makefile b/arch/sh/kernel/Makefile
index aa0fbc9202b1..69cd9ac4b2ab 100644
--- a/arch/sh/kernel/Makefile
+++ b/arch/sh/kernel/Makefile
@@ -3,7 +3,7 @@
 # Makefile for the Linux/SuperH kernel.
 #
 
-extra-y	:= head_32.o vmlinux.lds
+extra-y	:= vmlinux.lds
 
 ifdef CONFIG_FUNCTION_TRACER
 # Do not profile debug and lowlevel utilities
@@ -12,7 +12,7 @@ endif
 
 CFLAGS_REMOVE_return_address.o = -pg
 
-obj-y	:= debugtraps.o dumpstack.o 		\
+obj-y	:= head_32.o debugtraps.o dumpstack.o				\
 	   idle.o io.o irq.o irq_32.o kdebugfs.o			\
 	   machvec.o nmi_debug.o process.o				\
 	   process_32.o ptrace.o ptrace_32.o				\
diff --git a/arch/sparc/kernel/Makefile b/arch/sparc/kernel/Makefile
index d3a0e072ebe8..b328e4a0bd57 100644
--- a/arch/sparc/kernel/Makefile
+++ b/arch/sparc/kernel/Makefile
@@ -7,8 +7,6 @@
 asflags-y := -ansi
 ccflags-y := -Werror
 
-extra-y     := head_$(BITS).o
-
 # Undefine sparc when processing vmlinux.lds - it is used
 # And teach CPP we are doing $(BITS) builds (for this case)
 CPPFLAGS_vmlinux.lds := -Usparc -m$(BITS)
@@ -22,6 +20,7 @@ CFLAGS_REMOVE_perf_event.o := -pg
 CFLAGS_REMOVE_pcr.o := -pg
 endif
 
+obj-y                   := head_$(BITS).o
 obj-$(CONFIG_SPARC64)   += urtt_fill.o
 obj-$(CONFIG_SPARC32)   += entry.o wof.o wuf.o
 obj-$(CONFIG_SPARC32)   += etrap_32.o
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index a20a5ebfacd7..956e50ca06e0 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -3,10 +3,6 @@
 # Makefile for the linux kernel.
 #
 
-extra-y	:= head_$(BITS).o
-extra-y	+= head$(BITS).o
-extra-y	+= ebda.o
-extra-y	+= platform-quirks.o
 extra-y	+= vmlinux.lds
 
 CPPFLAGS_vmlinux.lds += -U$(UTS_MACHINE)
@@ -42,7 +38,11 @@ KCOV_INSTRUMENT		:= n
 
 CFLAGS_irq.o := -I $(srctree)/$(src)/../include/asm/trace
 
-obj-y			:= process_$(BITS).o signal.o
+obj-y			+= head_$(BITS).o
+obj-y			+= head$(BITS).o
+obj-y			+= ebda.o
+obj-y			+= platform-quirks.o
+obj-y			+= process_$(BITS).o signal.o
 obj-$(CONFIG_COMPAT)	+= signal_compat.o
 obj-y			+= traps.o idt.o irq.o irq_$(BITS).o dumpstack_$(BITS).o
 obj-y			+= time.o ioport.o dumpstack.o nmi.o
diff --git a/arch/xtensa/kernel/Makefile b/arch/xtensa/kernel/Makefile
index 897c1c741058..f28b8e3d717e 100644
--- a/arch/xtensa/kernel/Makefile
+++ b/arch/xtensa/kernel/Makefile
@@ -3,9 +3,9 @@
 # Makefile for the Linux/Xtensa kernel.
 #
 
-extra-y := head.o vmlinux.lds
+extra-y := vmlinux.lds
 
-obj-y := align.o coprocessor.o entry.o irq.o platform.o process.o \
+obj-y := head.o align.o coprocessor.o entry.o irq.o platform.o process.o \
 	 ptrace.o setup.o signal.o stacktrace.o syscall.o time.o traps.o \
 	 vectors.o
 
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 40a3e9b0512b..7740ce3b29e8 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -70,13 +70,12 @@ quiet_cmd_vmlinux_objs = GEN     $@
 	for f in $(real-prereqs); do	\
 		case $${f} in		\
 		*libgcc.a) ;;		\
-		*.a) $(AR) t $${f} ;;	\
-		*) echo $${f} ;;	\
+		*) $(AR) t $${f} ;;	\
 		esac			\
 	done > $@
 
 targets += .vmlinux.objs
-.vmlinux.objs: $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
+.vmlinux.objs: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
 	$(call if_changed,vmlinux_objs)
 
 vmlinux.o-if-present := $(wildcard vmlinux.o)
diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o
index 7d531b825712..68c22879bade 100644
--- a/scripts/Makefile.vmlinux_o
+++ b/scripts/Makefile.vmlinux_o
@@ -18,7 +18,7 @@ quiet_cmd_gen_initcalls_lds = GEN     $@
 	$(PERL) $(real-prereqs) > $@
 
 .tmp_initcalls.lds: $(srctree)/scripts/generate_initcall_order.pl \
-		$(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
+		vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
 	$(call if_changed,gen_initcalls_lds)
 
 targets := .tmp_initcalls.lds
@@ -48,7 +48,7 @@ quiet_cmd_ld_vmlinux.o = LD      $@
       cmd_ld_vmlinux.o = \
 	$(LD) ${KBUILD_LDFLAGS} -r -o $@ \
 	$(addprefix -T , $(initcalls-lds)) \
-	--whole-archive $(KBUILD_VMLINUX_OBJS) --no-whole-archive \
+	--whole-archive vmlinux.a --no-whole-archive \
 	--start-group $(KBUILD_VMLINUX_LIBS) --end-group \
 	$(cmd_objtool)
 
@@ -57,7 +57,7 @@ define rule_ld_vmlinux.o
 	$(call cmd,gen_objtooldep)
 endef
 
-vmlinux.o: $(initcalls-lds) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
+vmlinux.o: $(initcalls-lds) vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
 	$(call if_changed_rule,ld_vmlinux.o)
 
 targets += vmlinux.o
diff --git a/scripts/clang-tools/gen_compile_commands.py b/scripts/clang-tools/gen_compile_commands.py
index 47da25b3ba7d..d800b2c0af97 100755
--- a/scripts/clang-tools/gen_compile_commands.py
+++ b/scripts/clang-tools/gen_compile_commands.py
@@ -109,20 +109,6 @@ def to_cmdfile(path):
     return os.path.join(dir, '.' + base + '.cmd')
 
 
-def cmdfiles_for_o(obj):
-    """Generate the iterator of .cmd files associated with the object
-
-    Yield the .cmd file used to build the given object
-
-    Args:
-        obj: The object path
-
-    Yields:
-        The path to .cmd file
-    """
-    yield to_cmdfile(obj)
-
-
 def cmdfiles_for_a(archive, ar):
     """Generate the iterator of .cmd files associated with the archive.
 
@@ -211,13 +197,10 @@ def main():
     for path in paths:
         # If 'path' is a directory, handle all .cmd files under it.
         # Otherwise, handle .cmd files associated with the file.
-        # Most of built-in objects are linked via archives (built-in.a or lib.a)
-        # but some objects are linked to vmlinux directly.
+        # built-in objects are linked via vmlinux.a
         # Modules are listed in modules.order.
         if os.path.isdir(path):
             cmdfiles = cmdfiles_in_dir(path)
-        elif path.endswith('.o'):
-            cmdfiles = cmdfiles_for_o(path)
         elif path.endswith('.a'):
             cmdfiles = cmdfiles_for_a(path, ar)
         elif path.endswith('modules.order'):
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 6a197d8a88ac..23ac13fd9d89 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -3,17 +3,15 @@
 #
 # link vmlinux
 #
-# vmlinux is linked from the objects selected by $(KBUILD_VMLINUX_OBJS) and
-# $(KBUILD_VMLINUX_LIBS). Most are built-in.a files from top-level directories
-# in the kernel tree, others are specified in arch/$(ARCH)/Makefile.
+# vmlinux is linked from the objects in vmlinux.a and $(KBUILD_VMLINUX_LIBS).
+# vmlinux.a contains objects that are linked unconditionally.
 # $(KBUILD_VMLINUX_LIBS) are archives which are linked conditionally
 # (not within --whole-archive), and do not require symbol indexes added.
 #
 # vmlinux
 #   ^
 #   |
-#   +--< $(KBUILD_VMLINUX_OBJS)
-#   |    +--< init/built-in.a drivers/built-in.a mm/built-in.a + more
+#   +--< vmlinux.a
 #   |
 #   +--< $(KBUILD_VMLINUX_LIBS)
 #   |    +--< lib/lib.a + more
@@ -67,7 +65,7 @@ vmlinux_link()
 		objs=vmlinux.o
 		libs=
 	else
-		objs="${KBUILD_VMLINUX_OBJS}"
+		objs=vmlinux.a
 		libs="${KBUILD_VMLINUX_LIBS}"
 	fi
 
-- 
cgit v1.2.3


From ce697ccee1a8661da4e23fbe5f3d45d8d6922c20 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <masahiroy@kernel.org>
Date: Sun, 25 Sep 2022 03:19:15 +0900
Subject: kbuild: remove head-y syntax

Kbuild puts the objects listed in head-y at the head of vmlinux.
Conventionally, we do this for head*.S, which contains the kernel entry
point.

A counter approach is to control the section order by the linker script.
Actually, the code marked as __HEAD goes into the ".head.text" section,
which is placed before the normal ".text" section.

I do not know if both of them are needed. From the build system
perspective, head-y is not mandatory. If you can achieve the proper code
placement by the linker script only, it would be cleaner.

I collected the current head-y objects into head-object-list.txt. It is
a whitelist. My hope is it will be reduced in the long run.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
---
 Documentation/kbuild/makefiles.rst |  9 ++++---
 Makefile                           |  4 +--
 arch/alpha/Makefile                |  2 --
 arch/arc/Makefile                  |  2 --
 arch/arm/Makefile                  |  3 ---
 arch/arm64/Makefile                |  3 ---
 arch/csky/Makefile                 |  2 --
 arch/hexagon/Makefile              |  2 --
 arch/ia64/Makefile                 |  1 -
 arch/loongarch/Makefile            |  2 --
 arch/m68k/Makefile                 |  9 -------
 arch/microblaze/Makefile           |  1 -
 arch/mips/Makefile                 |  2 --
 arch/nios2/Makefile                |  1 -
 arch/openrisc/Makefile             |  2 --
 arch/parisc/Makefile               |  2 --
 arch/powerpc/Makefile              | 12 ---------
 arch/riscv/Makefile                |  2 --
 arch/s390/Makefile                 |  2 --
 arch/sh/Makefile                   |  2 --
 arch/sparc/Makefile                |  2 --
 arch/x86/Makefile                  |  5 ----
 arch/xtensa/Makefile               |  2 --
 scripts/head-object-list.txt       | 53 ++++++++++++++++++++++++++++++++++++++
 24 files changed, 60 insertions(+), 67 deletions(-)
 create mode 100644 scripts/head-object-list.txt

(limited to 'Documentation/kbuild/makefiles.rst')

diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
index 5a6a8426cc97..60134ddf3db1 100644
--- a/Documentation/kbuild/makefiles.rst
+++ b/Documentation/kbuild/makefiles.rst
@@ -1070,8 +1070,7 @@ When kbuild executes, the following steps are followed (roughly):
    - The values of the above variables are expanded in arch/$(SRCARCH)/Makefile.
 5) All object files are then linked and the resulting file vmlinux is
    located at the root of the obj tree.
-   The very first objects linked are listed in head-y, assigned by
-   arch/$(SRCARCH)/Makefile.
+   The very first objects linked are listed in scripts/head-object-list.txt.
 6) Finally, the architecture-specific part does any required post processing
    and builds the final bootimage.
    - This includes building boot records
@@ -1219,6 +1218,9 @@ When kbuild executes, the following steps are followed (roughly):
 	All object files for vmlinux. They are linked to vmlinux in the same
 	order as listed in KBUILD_VMLINUX_OBJS.
 
+	The objects listed in scripts/head-object-list.txt are exceptions;
+	they are placed before the other objects.
+
     KBUILD_VMLINUX_LIBS
 
 	All .a "lib" files for vmlinux. KBUILD_VMLINUX_OBJS and
@@ -1262,8 +1264,7 @@ When kbuild executes, the following steps are followed (roughly):
 	machinery is all architecture-independent.
 
 
-	head-y, core-y, libs-y, drivers-y
-	    $(head-y) lists objects to be linked first in vmlinux.
+	core-y, libs-y, drivers-y
 
 	    $(libs-y) lists directories where a lib.a archive can be located.
 
diff --git a/Makefile b/Makefile
index 8da45f76ec31..e4186c171049 100644
--- a/Makefile
+++ b/Makefile
@@ -1147,10 +1147,10 @@ quiet_cmd_ar_vmlinux.a = AR      $@
       cmd_ar_vmlinux.a = \
 	rm -f $@; \
 	$(AR) cDPrST $@ $(KBUILD_VMLINUX_OBJS); \
-	$(AR) mPiT $$($(AR) t $@ | head -n1) $@ $(head-y)
+	$(AR) mPiT $$($(AR) t $@ | head -n1) $@ $$($(AR) t $@ | grep -F --file=$(srctree)/scripts/head-object-list.txt)
 
 targets += vmlinux.a
-vmlinux.a: $(KBUILD_VMLINUX_OBJS) autoksyms_recursive FORCE
+vmlinux.a: $(KBUILD_VMLINUX_OBJS) scripts/head-object-list.txt autoksyms_recursive FORCE
 	$(call if_changed,ar_vmlinux.a)
 
 vmlinux.o: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
diff --git a/arch/alpha/Makefile b/arch/alpha/Makefile
index 881cb913e23a..45158024085e 100644
--- a/arch/alpha/Makefile
+++ b/arch/alpha/Makefile
@@ -36,8 +36,6 @@ cflags-y				+= $(cpuflags-y)
 # BWX is most important, but we don't really want any emulation ever.
 KBUILD_CFLAGS += $(cflags-y) -Wa,-mev6
 
-head-y := arch/alpha/kernel/head.o
-
 libs-y				+= arch/alpha/lib/
 
 # export what is needed by arch/alpha/boot/Makefile
diff --git a/arch/arc/Makefile b/arch/arc/Makefile
index efc54f3e35e0..329400a1c355 100644
--- a/arch/arc/Makefile
+++ b/arch/arc/Makefile
@@ -82,8 +82,6 @@ KBUILD_CFLAGS	+= $(cflags-y)
 KBUILD_AFLAGS	+= $(KBUILD_CFLAGS)
 KBUILD_LDFLAGS	+= $(ldflags-y)
 
-head-y		:= arch/arc/kernel/head.o
-
 # w/o this dtb won't embed into kernel binary
 core-y		+= arch/arc/boot/dts/
 
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 56f655deebb1..29d15c9a433e 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -134,9 +134,6 @@ KBUILD_AFLAGS	+=$(CFLAGS_ABI) $(AFLAGS_ISA) $(arch-y) $(tune-y) -include asm/uni
 
 CHECKFLAGS	+= -D__arm__
 
-#Default value
-head-y		:= arch/arm/kernel/head$(MMUEXT).o
-
 # Text offset. This list is sorted numerically by address in order to
 # provide a means to avoid/resolve conflicts in multi-arch kernels.
 # Note: the 32kB below this value is reserved for use by the kernel
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 6d9d4a58b898..6e03f15bb041 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -133,9 +133,6 @@ ifeq ($(CONFIG_DYNAMIC_FTRACE_WITH_REGS),y)
   CC_FLAGS_FTRACE := -fpatchable-function-entry=2
 endif
 
-# Default value
-head-y		:= arch/arm64/kernel/head.o
-
 ifeq ($(CONFIG_KASAN_SW_TAGS), y)
 KASAN_SHADOW_SCALE_SHIFT := 4
 else ifeq ($(CONFIG_KASAN_GENERIC), y)
diff --git a/arch/csky/Makefile b/arch/csky/Makefile
index 4e1d619fd5c6..0e4237e55758 100644
--- a/arch/csky/Makefile
+++ b/arch/csky/Makefile
@@ -59,8 +59,6 @@ LDFLAGS += -EL
 
 KBUILD_AFLAGS += $(KBUILD_CFLAGS)
 
-head-y := arch/csky/kernel/head.o
-
 core-y += arch/csky/$(CSKYABI)/
 
 libs-y += arch/csky/lib/ \
diff --git a/arch/hexagon/Makefile b/arch/hexagon/Makefile
index 44312bc147d8..92d005958dfb 100644
--- a/arch/hexagon/Makefile
+++ b/arch/hexagon/Makefile
@@ -32,5 +32,3 @@ KBUILD_LDFLAGS += $(ldflags-y)
 TIR_NAME := r19
 KBUILD_CFLAGS += -ffixed-$(TIR_NAME) -DTHREADINFO_REG=$(TIR_NAME) -D__linux__
 KBUILD_AFLAGS += -DTHREADINFO_REG=$(TIR_NAME)
-
-head-y := arch/hexagon/kernel/head.o
diff --git a/arch/ia64/Makefile b/arch/ia64/Makefile
index e55c2f138656..56c4bb276b6e 100644
--- a/arch/ia64/Makefile
+++ b/arch/ia64/Makefile
@@ -44,7 +44,6 @@ quiet_cmd_objcopy = OBJCOPY $@
 cmd_objcopy = $(OBJCOPY) $(OBJCOPYFLAGS) $(OBJCOPYFLAGS_$(@F)) $< $@
 
 KBUILD_CFLAGS += $(cflags-y)
-head-y := arch/ia64/kernel/head.o
 
 libs-y				+= arch/ia64/lib/
 
diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
index ec3de6191276..131fc210c2bf 100644
--- a/arch/loongarch/Makefile
+++ b/arch/loongarch/Makefile
@@ -72,8 +72,6 @@ CHECKFLAGS += $(shell $(CC) $(KBUILD_CFLAGS) -dM -E -x c /dev/null | \
 	sed -e "s/^\#define /-D'/" -e "s/ /'='/" -e "s/$$/'/" -e 's/\$$/&&/g')
 endif
 
-head-y := arch/loongarch/kernel/head.o
-
 libs-y += arch/loongarch/lib/
 
 ifeq ($(KBUILD_EXTMOD),)
diff --git a/arch/m68k/Makefile b/arch/m68k/Makefile
index e358605b70ba..43e39040d3ac 100644
--- a/arch/m68k/Makefile
+++ b/arch/m68k/Makefile
@@ -86,15 +86,6 @@ ifdef CONFIG_KGDB
 KBUILD_CFLAGS := $(subst -fomit-frame-pointer,,$(KBUILD_CFLAGS)) -g
 endif
 
-#
-# Select the assembler head startup code. Order is important. The default
-# head code is first, processor specific selections can override it after.
-#
-head-y				:= arch/m68k/kernel/head.o
-head-$(CONFIG_SUN3)		:= arch/m68k/kernel/sun3-head.o
-head-$(CONFIG_M68000)		:= arch/m68k/68000/head.o
-head-$(CONFIG_COLDFIRE)		:= arch/m68k/coldfire/head.o
-
 libs-y				+= arch/m68k/lib/
 
 
diff --git a/arch/microblaze/Makefile b/arch/microblaze/Makefile
index 1826d9ce4459..3f8a86c4336a 100644
--- a/arch/microblaze/Makefile
+++ b/arch/microblaze/Makefile
@@ -48,7 +48,6 @@ CPUFLAGS-1 += $(call cc-option,-mcpu=v$(CPU_VER))
 # r31 holds current when in kernel mode
 KBUILD_CFLAGS += -ffixed-r31 $(CPUFLAGS-y) $(CPUFLAGS-1) $(CPUFLAGS-2)
 
-head-y := arch/microblaze/kernel/head.o
 libs-y += arch/microblaze/lib/
 
 boot := arch/microblaze/boot
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index 4d2a3e73fc45..b296e33f8e33 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -324,8 +324,6 @@ endif
 
 OBJCOPYFLAGS		+= --remove-section=.reginfo
 
-head-y := arch/mips/kernel/head.o
-
 libs-y			+= arch/mips/lib/
 libs-$(CONFIG_MIPS_FP_SUPPORT) += arch/mips/math-emu/
 
diff --git a/arch/nios2/Makefile b/arch/nios2/Makefile
index 3f34e6831863..f1ff4ce0f1a2 100644
--- a/arch/nios2/Makefile
+++ b/arch/nios2/Makefile
@@ -37,7 +37,6 @@ KBUILD_CFLAGS += -DUTS_SYSNAME=\"$(UTS_SYSNAME)\"
 KBUILD_CFLAGS += -fno-builtin
 KBUILD_CFLAGS += -G 0
 
-head-y		:= arch/nios2/kernel/head.o
 libs-y		+= arch/nios2/lib/ $(LIBGCC)
 
 INSTALL_PATH ?= /tftpboot
diff --git a/arch/openrisc/Makefile b/arch/openrisc/Makefile
index b446510173cd..68249521db5a 100644
--- a/arch/openrisc/Makefile
+++ b/arch/openrisc/Makefile
@@ -55,8 +55,6 @@ ifeq ($(CONFIG_OPENRISC_HAVE_INST_SEXT),y)
 	KBUILD_CFLAGS += $(call cc-option,-msext)
 endif
 
-head-y 		:= arch/openrisc/kernel/head.o
-
 libs-y		+= $(LIBGCC)
 
 PHONY += vmlinux.bin
diff --git a/arch/parisc/Makefile b/arch/parisc/Makefile
index e38d993d87f2..a2d8600521f9 100644
--- a/arch/parisc/Makefile
+++ b/arch/parisc/Makefile
@@ -113,8 +113,6 @@ cflags-$(CONFIG_PA7100LC)	+= -march=1.1 -mschedule=7100LC
 cflags-$(CONFIG_PA7300LC)	+= -march=1.1 -mschedule=7300
 cflags-$(CONFIG_PA8X00)		+= -march=2.0 -mschedule=8000
 
-head-y			:= arch/parisc/kernel/head.o 
-
 KBUILD_CFLAGS	+= $(cflags-y)
 LIBGCC		:= $(shell $(CC) -print-libgcc-file-name)
 export LIBGCC
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 02742facf895..89c27827a11f 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -226,18 +226,6 @@ KBUILD_CFLAGS += $(cpu-as-y)
 KBUILD_AFLAGS += $(aflags-y)
 KBUILD_CFLAGS += $(cflags-y)
 
-head-$(CONFIG_PPC64)		:= arch/powerpc/kernel/head_64.o
-head-$(CONFIG_PPC_BOOK3S_32)	:= arch/powerpc/kernel/head_book3s_32.o
-head-$(CONFIG_PPC_8xx)		:= arch/powerpc/kernel/head_8xx.o
-head-$(CONFIG_40x)		:= arch/powerpc/kernel/head_40x.o
-head-$(CONFIG_44x)		:= arch/powerpc/kernel/head_44x.o
-head-$(CONFIG_FSL_BOOKE)	:= arch/powerpc/kernel/head_fsl_booke.o
-
-head-$(CONFIG_PPC64)		+= arch/powerpc/kernel/entry_64.o
-head-$(CONFIG_PPC_FPU)		+= arch/powerpc/kernel/fpu.o
-head-$(CONFIG_ALTIVEC)		+= arch/powerpc/kernel/vector.o
-head-$(CONFIG_PPC_OF_BOOT_TRAMPOLINE)  += arch/powerpc/kernel/prom_init.o
-
 # Default to zImage, override when needed
 all: zImage
 
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 3fa8ef336822..e013df8e7b8b 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -110,8 +110,6 @@ else
 KBUILD_IMAGE	:= $(boot)/Image.gz
 endif
 
-head-y := arch/riscv/kernel/head.o
-
 libs-y += arch/riscv/lib/
 libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
 
diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index 4cb5d17e7ead..de6d8b2ea4d8 100644
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -119,8 +119,6 @@ export KBUILD_CFLAGS_DECOMPRESSOR
 
 OBJCOPYFLAGS	:= -O binary
 
-head-y		:= arch/s390/kernel/head64.o
-
 libs-y		+= arch/s390/lib/
 drivers-y	+= drivers/s390/
 
diff --git a/arch/sh/Makefile b/arch/sh/Makefile
index b39412bf91fb..5c8776482530 100644
--- a/arch/sh/Makefile
+++ b/arch/sh/Makefile
@@ -114,8 +114,6 @@ endif
 
 export ld-bfd
 
-head-y	:= arch/sh/kernel/head_32.o
-
 # Mach groups
 machdir-$(CONFIG_SOLUTION_ENGINE)		+= mach-se
 machdir-$(CONFIG_SH_HP6XX)			+= mach-hp6xx
diff --git a/arch/sparc/Makefile b/arch/sparc/Makefile
index fe58a410b4ce..a4ea5b05f288 100644
--- a/arch/sparc/Makefile
+++ b/arch/sparc/Makefile
@@ -56,8 +56,6 @@ endif
 
 endif
 
-head-y                 := arch/sparc/kernel/head_$(BITS).o
-
 libs-y                 += arch/sparc/prom/
 libs-y                 += arch/sparc/lib/
 
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index bafbd905e6e7..9afd323c6916 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -234,11 +234,6 @@ archheaders:
 ###
 # Kernel objects
 
-head-y := arch/x86/kernel/head_$(BITS).o
-head-y += arch/x86/kernel/head$(BITS).o
-head-y += arch/x86/kernel/ebda.o
-head-y += arch/x86/kernel/platform-quirks.o
-
 libs-y  += arch/x86/lib/
 
 # drivers-y are linked after core-y
diff --git a/arch/xtensa/Makefile b/arch/xtensa/Makefile
index 5097caa7bf0c..bfd8e433ed62 100644
--- a/arch/xtensa/Makefile
+++ b/arch/xtensa/Makefile
@@ -55,8 +55,6 @@ KBUILD_CPPFLAGS += $(patsubst %,-I$(srctree)/%include,$(vardirs) $(plfdirs))
 
 KBUILD_DEFCONFIG := iss_defconfig
 
-head-y		:= arch/xtensa/kernel/head.o
-
 libs-y		+= arch/xtensa/lib/
 
 boot		:= arch/xtensa/boot
diff --git a/scripts/head-object-list.txt b/scripts/head-object-list.txt
new file mode 100644
index 000000000000..dd2ba2eda636
--- /dev/null
+++ b/scripts/head-object-list.txt
@@ -0,0 +1,53 @@
+# Head objects
+#
+# The objects listed here are placed at the head of vmlinux. A typical use-case
+# is an object that contains the entry point. This is kept for compatibility
+# with head-y, which Kbuild used to support.
+#
+# A counter approach is to control the section placement by the linker script.
+# The code marked as __HEAD goes into the ".head.text" section, which is placed
+# before the normal ".text" section.
+#
+# If you can achieve the correct code ordering by linker script, please delete
+# the entry from this file.
+#
+arch/alpha/kernel/head.o
+arch/arc/kernel/head.o
+arch/arm/kernel/head-nommu.o
+arch/arm/kernel/head.o
+arch/arm64/kernel/head.o
+arch/csky/kernel/head.o
+arch/hexagon/kernel/head.o
+arch/ia64/kernel/head.o
+arch/loongarch/kernel/head.o
+arch/m68k/68000/head.o
+arch/m68k/coldfire/head.o
+arch/m68k/kernel/head.o
+arch/m68k/kernel/sun3-head.o
+arch/microblaze/kernel/head.o
+arch/mips/kernel/head.o
+arch/nios2/kernel/head.o
+arch/openrisc/kernel/head.o
+arch/parisc/kernel/head.o
+arch/powerpc/kernel/head_40x.o
+arch/powerpc/kernel/head_44x.o
+arch/powerpc/kernel/head_64.o
+arch/powerpc/kernel/head_8xx.o
+arch/powerpc/kernel/head_book3s_32.o
+arch/powerpc/kernel/head_fsl_booke.o
+arch/powerpc/kernel/entry_64.o
+arch/powerpc/kernel/fpu.o
+arch/powerpc/kernel/vector.o
+arch/powerpc/kernel/prom_init.o
+arch/riscv/kernel/head.o
+arch/s390/kernel/head64.o
+arch/sh/kernel/head_32.o
+arch/sparc/kernel/head_32.o
+arch/sparc/kernel/head_64.o
+arch/x86/kernel/head_32.o
+arch/x86/kernel/head_64.o
+arch/x86/kernel/head32.o
+arch/x86/kernel/head64.o
+arch/x86/kernel/ebda.o
+arch/x86/kernel/platform-quirks.o
+arch/xtensa/kernel/head.o
-- 
cgit v1.2.3