[PATCH v14 09/11] x86, arm64: Add ARCH_WANT_RESERVE_CRASH_KERNEL config

[Chen Zhou <chenzhou10@huawei.com>]

We make the functions reserve_crashkernel[_low]() as generic for
x86 and arm64. Since reserve_crashkernel[_low]() implementations
are quite similar on other architectures as well, we can have more
users of this later.

So have CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL in arch/Kconfig and
select this by X86 and ARM64.

Suggested-by: Mike Rapoport <rppt@kernel.org>
Suggested-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
---
 arch/Kconfig        | 3 +++
 arch/arm64/Kconfig  | 1 +
 arch/x86/Kconfig    | 2 ++
 kernel/crash_core.c | 7 ++-----
 4 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 24862d15f3a3..0ca1ff5bb157 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -24,6 +24,9 @@ config KEXEC_ELF
 config HAVE_IMA_KEXEC
 	bool
 
+config ARCH_WANT_RESERVE_CRASH_KERNEL
+	bool
+
 config SET_FS
 	bool
 
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index f39568b28ec1..09365c7ff469 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -82,6 +82,7 @@ config ARM64
 	select ARCH_WANT_FRAME_POINTERS
 	select ARCH_WANT_HUGE_PMD_SHARE if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
 	select ARCH_WANT_LD_ORPHAN_WARN
+	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
 	select ARCH_HAS_UBSAN_SANITIZE_ALL
 	select ARM_AMBA
 	select ARM_ARCH_TIMER
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 21f851179ff0..e6926fcb4a40 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -12,6 +12,7 @@ config X86_32
 	depends on !64BIT
 	# Options that are inherently 32-bit kernel only:
 	select ARCH_WANT_IPC_PARSE_VERSION
+	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
 	select CLKSRC_I8253
 	select CLONE_BACKWARDS
 	select GENERIC_VDSO_32
@@ -28,6 +29,7 @@ config X86_64
 	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
 	select ARCH_USE_CMPXCHG_LOCKREF
+	select ARCH_WANT_RESERVE_CRASH_KERNEL if KEXEC_CORE
 	select HAVE_ARCH_SOFT_DIRTY
 	select MODULES_USE_ELF_RELA
 	select NEED_DMA_MAP_STATE
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 8479be270c0b..2c5783985db5 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -320,9 +320,7 @@ int __init parse_crashkernel_low(char *cmdline,
  * --------- Crashkernel reservation ------------------------------
  */
 
-#ifdef CONFIG_KEXEC_CORE
-
-#if defined(CONFIG_X86) || defined(CONFIG_ARM64)
+#ifdef CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL
 static int __init reserve_crashkernel_low(void)
 {
 #ifdef CONFIG_64BIT
@@ -450,8 +448,7 @@ void __init reserve_crashkernel(void)
 	crashk_res.start = crash_base;
 	crashk_res.end   = crash_base + crash_size - 1;
 }
-#endif
-#endif /* CONFIG_KEXEC_CORE */
+#endif /* CONFIG_ARCH_WANT_RESERVE_CRASH_KERNEL */
 
 Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
 			  void *data, size_t data_len)
-- 
2.20.1