riscv/kexec: refactor for kernel/Kconfig.kexec

The kexec and crash kernel options are provided in the common
kernel/Kconfig.kexec. Utilize the common options and provide
the ARCH_SUPPORTS_ and ARCH_SELECTS_ entries to recreate the
equivalent set of KEXEC and CRASH options.

Link: https://lkml.kernel.org/r/20230712161545.87870-12-eric.devolder@oracle.comSigned-off-by: Eric DeVolder <eric.devolder@oracle.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/riscv/Kconfig

@@ -650,48 +650,30 @@ config RISCV_BOOT_SPINWAIT
 
 	  If unsure what to do here, say N.
 
-config KEXEC
-	bool "Kexec system call"
-	depends on MMU
+config ARCH_SUPPORTS_KEXEC
+	def_bool MMU
+
+config ARCH_SELECTS_KEXEC
+	def_bool y
+	depends on KEXEC
 	select HOTPLUG_CPU if SMP
-	select KEXEC_CORE
-	help
-	  kexec is a system call that implements the ability to shutdown your
-	  current kernel, and to start another kernel. It is like a reboot
-	  but it is independent of the system firmware. And like a reboot
-	  you can start any kernel with it, not just Linux.
 
-	  The name comes from the similarity to the exec system call.
+config ARCH_SUPPORTS_KEXEC_FILE
+	def_bool 64BIT && MMU
 
-config KEXEC_FILE
-	bool "kexec file based systmem call"
-	depends on 64BIT && MMU
+config ARCH_SELECTS_KEXEC_FILE
+	def_bool y
+	depends on KEXEC_FILE
 	select HAVE_IMA_KEXEC if IMA
-	select KEXEC_CORE
 	select KEXEC_ELF
-	help
-	  This is new version of kexec system call. This system call is
-	  file based and takes file descriptors as system call argument
-	  for kernel and initramfs as opposed to list of segments as
-	  accepted by previous system call.
-
-	  If you don't know what to do here, say Y.
 
 config ARCH_HAS_KEXEC_PURGATORY
 	def_bool KEXEC_FILE
 	depends on CRYPTO=y
 	depends on CRYPTO_SHA256=y
 
-config CRASH_DUMP
-	bool "Build kdump crash kernel"
-	help
-	  Generate crash dump after being started by kexec. This should
-	  be normally only set in special crash dump kernels which are
-	  loaded in the main kernel with kexec-tools into a specially
-	  reserved region and then later executed after a crash by
-	  kdump/kexec.
-
-	  For more details see Documentation/admin-guide/kdump/kdump.rst
+config ARCH_SUPPORTS_CRASH_DUMP
+	def_bool y
 
 config COMPAT
 	bool "Kernel support for 32-bit U-mode"