Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20220906061313.1445810-1-masahiroy@kernel.org> <20220906061313.1445810-8-masahiroy@kernel.org>
In-Reply-To: <20220906061313.1445810-8-masahiroy@kernel.org>
From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Mon, 19 Sep 2022 10:10:21 +0200
Message-ID: <CAMuHMdUpY92WGNqTOV0-jaB+q1q0nS4wxkhrC8jb-uGU9KbogQ@mail.gmail.com>
Subject: Re: [PATCH v2 7/8] kbuild: use obj-y instead extra-y for objects
 placed at the head
To:     Masahiro Yamada <masahiroy@kernel.org>
Cc:     linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arch@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hi Yamada-san,

On Tue, Sep 6, 2022 at 8:15 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
> 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.
>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Thanks for your patch, which is now commit 6676e2cdd7c339dc ("kbuild:
use obj-y instead extra-y for objects placed at the head") in
next-20220916.

noreply@ellerman.id.au reported various build failures on m68k
since next-20220916, which I have bisected to the above commit:

m68k-linux-gnu-ld: warning: cannot find entry symbol _start;
defaulting to 0000000000001000
m68k-linux-gnu-ld: arch/m68k/kernel/setup.o: in function `setup_arch':
setup.c:(.init.text+0x2da): undefined reference to `availmem'
m68k-linux-gnu-ld: arch/m68k/kernel/early_printk.o: in function
`debug_cons_write':
early_printk.c:(.ref.text+0x28): undefined reference to `debug_cons_nputs'
m68k-linux-gnu-ld: arch/m68k/mm/init.o: in function `mem_init':
init.c:(.init.text+0x24): undefined reference to `kernel_pg_dir'
m68k-linux-gnu-ld: init.c:(.init.text+0x10): undefined reference to
`kernel_pg_dir'
m68k-linux-gnu-ld: init.c:(.init.text+0x1e): undefined reference to
`kernel_pg_dir'
m68k-linux-gnu-ld: arch/m68k/mm/motorola.o: in function `cache_page':
motorola.c:(.text+0xfc): undefined reference to `m68k_supervisor_cachemode'
m68k-linux-gnu-ld: arch/m68k/mm/motorola.o: in function `mmu_page_ctor':
motorola.c:(.text+0x162): undefined reference to `m68k_pgtable_cachemode'
m68k-linux-gnu-ld: arch/m68k/mm/motorola.o: in function `paging_init':
motorola.c:(.init.text+0x3d0): undefined reference to `kernel_pg_dir'
m68k-linux-gnu-ld: motorola.c:(.init.text+0x1d8): undefined reference
to `availmem'
m68k-linux-gnu-ld: motorola.c:(.init.text+0x32e): undefined reference
to `m68k_supervisor_cachemode'
m68k-linux-gnu-ld: motorola.c:(.init.text+0x3a6): undefined reference
to `kernel_pg_dir'
m68k-linux-gnu-ld: arch/m68k/q40/config.o: in function `q40_mem_console_write':
config.c:(.text+0x25c): undefined reference to `q40_mem_cptr'
m68k-linux-gnu-ld: config.c:(.text+0x254): undefined reference to `q40_mem_cptr'
m68k-linux-gnu-ld: arch/m68k/q40/config.o: in function `q40_debug_setup':
config.c:(.init.text+0x28): undefined reference to `q40_mem_cptr'
m68k-linux-gnu-ld: arch/m68k/mvme16x/config.o: in function `mvme16x_abort_int':
config.c:(.text+0x4): undefined reference to `mvme_bdid'
m68k-linux-gnu-ld: arch/m68k/mvme16x/config.o: in function `mvme16x_get_model':
config.c:(.text+0xc6): undefined reference to `mvme_bdid'
m68k-linux-gnu-ld: config.c:(.text+0xcc): undefined reference to `mvme_bdid'
m68k-linux-gnu-ld: config.c:(.text+0xe8): undefined reference to `mvme_bdid'
m68k-linux-gnu-ld: arch/m68k/mvme16x/config.o: in function
`mvme16x_get_hardware_list':
config.c:(.text+0x146): undefined reference to `mvme_bdid'
m68k-linux-gnu-ld: arch/m68k/mvme16x/config.o:config.c:(.text+0x1ce):
more undefined references to `mvme_bdid' follow
m68k-linux-gnu-ld: kernel/extable.o: in function `core_kernel_text':
extable.c:(.text+0x52): undefined reference to `_stext'
m68k-linux-gnu-ld: kernel/kallsyms.o: in function `is_ksym_addr':
kallsyms.c:(.text+0x28e): undefined reference to `_stext'
m68k-linux-gnu-ld: kernel/crash_core.o: in function
`crash_save_vmcoreinfo_init':
crash_core.c:(.init.text+0x4d8): undefined reference to `_stext'
m68k-linux-gnu-ld: crash_core.c:(.init.text+0x4c0): undefined
reference to `kernel_pg_dir'
m68k-linux-gnu-ld: mm/page_alloc.o: in function `mem_init_print_info':
page_alloc.c:(.init.text+0xfe4): undefined reference to `_stext'
m68k-linux-gnu-ld: page_alloc.c:(.init.text+0x103c): undefined
reference to `_stext'
m68k-linux-gnu-ld: mm/init-mm.o:(.data+0x24): undefined reference to
`kernel_pg_dir'
m68k-linux-gnu-ld: mm/usercopy.o: in function `__check_object_size':
usercopy.c:(.text+0x15a): undefined reference to `_stext'
make[1]: *** [Makefile:1175: vmlinux] Error 1


> ---
>
> (no changes since v1)
>
>  Documentation/kbuild/makefiles.rst          | 18 +----------------
>  Makefile                                    | 18 +++++++++++++----
>  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                   | 21 ++++++++++----------
>  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                | 22 ++++++++++-----------
>  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, 87 insertions(+), 112 deletions(-)
>
> diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
> index 11a296e52d68..07c7e5a843c1 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 f9ee16bd212d..f2d06aaaefd3 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1113,7 +1113,7 @@ clean-dirs        := $(vmlinux-alldirs)
>  export ARCH_CORE       := $(core-y)
>  export ARCH_DRIVERS    := $(drivers-y)
>  # Externally visible symbols (used by link-vmlinux.sh)
> -KBUILD_VMLINUX_OBJS := $(head-y) ./built-in.a
> +KBUILD_VMLINUX_OBJS := ./built-in.a
>  KBUILD_VMLINUX_OBJS += $(addsuffix built-in.a, $(filter %/, $(libs-y)))
>  ifdef CONFIG_MODULES
>  KBUILD_VMLINUX_OBJS += $(patsubst %/, %/lib.a, $(filter %/, $(libs-y)))
> @@ -1122,7 +1122,7 @@ 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
>  # used by scripts/Makefile.package
>  export KBUILD_ALLDIRS := $(sort $(filter-out arch/%,$(vmlinux-alldirs)) LICENSES arch include scripts tools)
> @@ -1151,8 +1151,18 @@ quiet_cmd_autoksyms_h = GEN     $@
>  $(autoksyms_h):
>         $(call cmd,autoksyms_h)
>
> +quiet_cmd_ar_vmlinux.a = AR      $@
> +      cmd_ar_vmlinux.a = \
> +       rm -f $@; \
> +       $(AR) cDPrST $@ $(KBUILD_VMLINUX_OBJS); \
> +       $(AR) mPi $$($(AR) t $@ | head -n1) $@ $(head-y)
> +
> +targets += vmlinux.a
> +vmlinux.a: $(KBUILD_VMLINUX_OBJS) FORCE
> +       $(call if_changed,ar_vmlinux.a)
> +
>  targets += vmlinux.o
> -vmlinux.o: autoksyms_recursive $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
> +vmlinux.o: autoksyms_recursive vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
>         $(Q)$(MAKE) -f $(srctree)/scripts/Makefile.vmlinux_o
>
>  ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
> @@ -1909,7 +1919,7 @@ 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..1755e6cd309f 100644
> --- a/arch/m68k/kernel/Makefile
> +++ b/arch/m68k/kernel/Makefile
> @@ -3,18 +3,19 @@
>  # 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-$(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
>
> 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..f264d9b2cb63 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
> @@ -198,12 +198,12 @@ 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
> +obj-$(CONFIG_PPC_OF_BOOT_TRAMPOLINE)   += prom_init_check
>
>  quiet_cmd_prom_init_check = PROMCHK $@
>        cmd_prom_init_check = $(CONFIG_SHELL) $< "$(NM)" $(obj)/prom_init.o; touch $@
> 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 d7d3138c5ecc..4f74370ad1ee 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 84019814f33f..81a4e0484457 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
> @@ -55,7 +55,7 @@ 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)
>
> @@ -64,7 +64,7 @@ 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
>
> --
> 2.34.1
>


--
Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds