feat: enable KEXEC_FILE_LOAD in the kernel

We don't enable `KEXEC_LOAD`, but only enable kexecing from the file
image, which is available on amd64/arm64.

Signed-off-by: Andrey Smirnov <andrey.smirnov@talos-systems.com>

kernel/kernel/config-amd64

@@ -131,6 +131,7 @@ CONFIG_RCU_STALL_COMMON=y
 CONFIG_RCU_NEED_SEGCBLIST=y
 # end of RCU Subsystem
 
+CONFIG_BUILD_BIN2C=y
 CONFIG_IKCONFIG=y
 CONFIG_IKCONFIG_PROC=y
 # CONFIG_IKHEADERS is not set
@@ -315,6 +316,7 @@ CONFIG_RETPOLINE=y
 CONFIG_X86_EXTENDED_PLATFORM=y
 # CONFIG_X86_NUMACHIP is not set
 # CONFIG_X86_VSMP is not set
+# CONFIG_X86_UV is not set
 # CONFIG_X86_GOLDFISH is not set
 # CONFIG_X86_INTEL_MID is not set
 # CONFIG_X86_INTEL_LPSS is not set
@@ -444,7 +446,9 @@ CONFIG_HZ_250=y
 CONFIG_HZ=250
 CONFIG_SCHED_HRTICK=y
 # CONFIG_KEXEC is not set
-# CONFIG_KEXEC_FILE is not set
+CONFIG_KEXEC_FILE=y
+CONFIG_ARCH_HAS_KEXEC_PURGATORY=y
+# CONFIG_KEXEC_SIG is not set
 CONFIG_CRASH_DUMP=y
 CONFIG_PHYSICAL_START=0x1000000
 CONFIG_RELOCATABLE=y
@@ -631,6 +635,7 @@ CONFIG_DMI_SCAN_MACHINE_NON_EFI_FALLBACK=y
 #
 CONFIG_EFI_VARS=y
 CONFIG_EFI_ESRT=y
+CONFIG_EFI_RUNTIME_MAP=y
 # CONFIG_EFI_FAKE_MEMMAP is not set
 CONFIG_EFI_RUNTIME_WRAPPERS=y
 CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER=y
@@ -680,6 +685,8 @@ CONFIG_AS_TPAUSE=y
 #
 # General architecture-dependent options
 #
+CONFIG_CRASH_CORE=y
+CONFIG_KEXEC_CORE=y
 CONFIG_HOTPLUG_SMT=y
 CONFIG_GENERIC_ENTRY=y
 # CONFIG_OPROFILE is not set

kernel/kernel/config-arm64

@@ -405,7 +405,8 @@ CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK=y
 CONFIG_PARAVIRT=y
 # CONFIG_PARAVIRT_TIME_ACCOUNTING is not set
 # CONFIG_KEXEC is not set
-# CONFIG_KEXEC_FILE is not set
+CONFIG_KEXEC_FILE=y
+# CONFIG_KEXEC_SIG is not set
 CONFIG_CRASH_DUMP=y
 CONFIG_XEN_DOM0=y
 CONFIG_XEN=y
@@ -738,6 +739,8 @@ CONFIG_CRYPTO_AES_ARM64_BS=y
 #
 # General architecture-dependent options
 #
+CONFIG_CRASH_CORE=y
+CONFIG_KEXEC_CORE=y
 CONFIG_SET_FS=y
 # CONFIG_KPROBES is not set
 CONFIG_JUMP_LABEL=y