[patch 25/41] kexec: make crashk_res, crashk_low_res and crash_notes symbols always visible

[Andrew Morton <akpm@linux-foundation.org>]

From: Jisheng Zhang <jszhang@kernel.org>
Subject: kexec: make crashk_res, crashk_low_res and crash_notes symbols always visible

Patch series "kexec: use IS_ENABLED(CONFIG_KEXEC_CORE) instead of #ifdef", v2.

Replace the conditional compilation using "#ifdef CONFIG_KEXEC_CORE" by a
check for "IS_ENABLED(CONFIG_KEXEC_CORE)", to simplify the code and
increase compile coverage.

I only modified x86, arm, arm64 and riscv, other architectures such as sh,
powerpc and s390 are better to be kept kexec code as-is so they are not
touched.


This patch (of 5):

Make the forward declarations of crashk_res, crashk_low_res and
crash_notes always visible.  Code referring to these symbols can then just
check for IS_ENABLED(CONFIG_KEXEC_CORE), instead of requiring conditional
compilation using an #ifdef, thus preparing to increase compile coverage
and simplify the code.

Link: https://lkml.kernel.org/r/20211206160514.2000-1-jszhang@kernel.org
Link: https://lkml.kernel.org/r/20211206160514.2000-2-jszhang@kernel.org
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Cc: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/kexec.h |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/include/linux/kexec.h~kexec-make-crashk_res-crashk_low_res-and-crash_notes-symbols-always-visible
+++ a/include/linux/kexec.h
@@ -20,6 +20,12 @@
 
 #include <uapi/linux/kexec.h>
 
+/* Location of a reserved region to hold the crash kernel.
+ */
+extern struct resource crashk_res;
+extern struct resource crashk_low_res;
+extern note_buf_t __percpu *crash_notes;
+
 #ifdef CONFIG_KEXEC_CORE
 #include <linux/list.h>
 #include <linux/compat.h>
@@ -350,12 +356,6 @@ extern int kexec_load_disabled;
 #define KEXEC_FILE_FLAGS	(KEXEC_FILE_UNLOAD | KEXEC_FILE_ON_CRASH | \
 				 KEXEC_FILE_NO_INITRAMFS)
 
-/* Location of a reserved region to hold the crash kernel.
- */
-extern struct resource crashk_res;
-extern struct resource crashk_low_res;
-extern note_buf_t __percpu *crash_notes;
-
 /* flag to track if kexec reboot is in progress */
 extern bool kexec_in_progress;
 
_