[PATCH v2] kexec_core: change dependency of object files

When dropping the select of KEXEC for CRASH_DUMP, compiling error
will be triggered if below config items are set on some architectures.

===
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_CRASH_DUMP=y
===

E.g the building error on loongarch:
---------------------------------------------------------------
loongarch64-linux-ld: kernel/kexec_core.o: in function `.L209':
>> kexec_core.c:(.text+0x1660): undefined reference to `machine_kexec_cleanup'
   loongarch64-linux-ld: kernel/kexec_core.o: in function `.L287':
>> kexec_core.c:(.text+0x1c5c): undefined reference to `machine_crash_shutdown'
>> loongarch64-linux-ld: kexec_core.c:(.text+0x1c64): undefined reference to `machine_kexec'
   loongarch64-linux-ld: kernel/kexec_core.o: in function `.L2^B5':
>> kexec_core.c:(.text+0x2090): undefined reference to `machine_shutdown'
   loongarch64-linux-ld: kexec_core.c:(.text+0x20a0): undefined reference to `machine_kexec'
---------------------------------------------------------------

The reason is that currently in arch/loongarch/kernel/Makefile, building
machine_kexec.o relocate_kernel.o depends on CONFIG_KEXEC. So the
building of the two object files is skipped because CONFIG_KEXEC=n in
that case.

And this situation exists in m68k, mips and sh ARCH too.

Here, changing the dependency of machine_kexec.o relocate_kernel.o to
CONFIG_KEXEC_CORE for all relevant architectures.

Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Signed-off-by: Baoquan He <[email protected]>
---
v1->v2:
- V1 only includes fix on loongarch. Add m68k, mips, sh fix in v2 too.

 arch/loongarch/kernel/Makefile | 2 +-
 arch/m68k/kernel/Makefile      | 2 +-
 arch/mips/kernel/Makefile      | 2 +-
 arch/sh/kernel/Makefile        | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index 4fcc168f0732..3c808c680370 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -57,7 +57,7 @@ obj-$(CONFIG_MAGIC_SYSRQ)	+= sysrq.o
 
 obj-$(CONFIG_RELOCATABLE)	+= relocate.o
 
-obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o
+obj-$(CONFIG_KEXEC_CORE)	+= machine_kexec.o relocate_kernel.o
 obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
 
 obj-$(CONFIG_UNWINDER_GUESS)	+= unwind_guess.o
diff --git a/arch/m68k/kernel/Makefile b/arch/m68k/kernel/Makefile
index 01fb69a5095f..f335bf3268a1 100644
--- a/arch/m68k/kernel/Makefile
+++ b/arch/m68k/kernel/Makefile
@@ -25,7 +25,7 @@ obj-$(CONFIG_PCI) += pcibios.o
 
 obj-$(CONFIG_M68K_NONCOHERENT_DMA) += dma.o
 
-obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o
+obj-$(CONFIG_KEXEC_CORE)	+= machine_kexec.o relocate_kernel.o
 obj-$(CONFIG_BOOTINFO_PROC)	+= bootinfo_proc.o
 obj-$(CONFIG_UBOOT)		+= uboot.o
 
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 853a43ee4b44..ecf3278a32f7 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -90,7 +90,7 @@ obj-$(CONFIG_GPIO_TXX9)		+= gpio_txx9.o
 
 obj-$(CONFIG_RELOCATABLE)	+= relocate.o
 
-obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o crash.o
+obj-$(CONFIG_KEXEC_CORE)	+= machine_kexec.o relocate_kernel.o crash.o
 obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 obj-$(CONFIG_EARLY_PRINTK_8250)	+= early_printk_8250.o
diff --git a/arch/sh/kernel/Makefile b/arch/sh/kernel/Makefile
index 69cd9ac4b2ab..2d7e70537de0 100644
--- a/arch/sh/kernel/Makefile
+++ b/arch/sh/kernel/Makefile
@@ -33,7 +33,7 @@ obj-$(CONFIG_SMP)		+= smp.o
 obj-$(CONFIG_SH_STANDARD_BIOS)	+= sh_bios.o
 obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_MODULES)		+= sh_ksyms_32.o module.o
-obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o
+obj-$(CONFIG_KEXEC_CORE)	+= machine_kexec.o relocate_kernel.o
 obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
 obj-$(CONFIG_STACKTRACE)	+= stacktrace.o
 obj-$(CONFIG_IO_TRAPPED)	+= io_trapped.o
-- 
2.41.0