scripts: clean up IA-64 code

A little more janitorial work after commit cf8e8658100d ("arch: Remove
Itanium (IA-64) architecture").

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

powerpc/64: Rename entry_64.S to prom_entry_64.S

This file contains only the enter_prom implementation now.
Trim includes and update header comment while we're here.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230606132447.315714-7-npiggin@gmail.com

scripts/head-object-list: Remove x86 from the list

Now that x86 boot code is not hardcoded to the particular linking
order, remove x86 files from the list and let them be placed inside
the vmlinux according only to the linker script and linker
preferences.

Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20230109170403.4117105-3-alexandr.lobakin@intel.com

riscv: remove special treatment for the link order of head.o

arch/riscv/kernel/head.o does not need any special treatment - the only
requirement is the ".head.text" section must be placed before the
normal ".text" section.

The linker script does the right thing to do. The build system does
not need to manipulate the link order of head.o.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Link: https://lore.kernel.org/r/20221018141200.1040-1-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arm64: remove special treatment for the link order of head.o

In the previous discussion (see the Link tag), Ard pointed out that
arm/arm64/kernel/head.o does not need any special treatment - the only
piece that must appear right at the start of the binary image is the
image header which is emitted into .head.text.

The linker script does the right thing to do. The build system does
not need to manipulate the link order of head.o.

Link: https://lore.kernel.org/lkml/CAMj1kXH77Ja8bSsq2Qj8Ck9iSZKw=1F8Uy-uAWGVDm4-CG=EuA@mail.gmail.com/
Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Link: https://lore.kernel.org/r/20221012233500.156764-1-masahiroy@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

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>