[PATCH linux-next 2/3] crash: fix building error in generic codes

[Baoquan He <bhe@redhat.com>]

Nathan reported some building errors on arm64 as below:

==========
$ curl -LSso .config https://github.com/archlinuxarm/PKGBUILDs/raw/master/core/linux-aarch64/config
$ make -skj"$(nproc)" ARCH=arm64 CROSS_COMPILE=aarch64-linux- olddefconfig all
...
aarch64-linux-ld: kernel/kexec_file.o: in function `kexec_walk_memblock.constprop.0':
kexec_file.c:(.text+0x314): undefined reference to `crashk_res'
...
aarch64-linux-ld: drivers/of/kexec.o: in function `of_kexec_alloc_and_setup_fdt':
kexec.c:(.text+0x580): undefined reference to `crashk_res'
...
aarch64-linux-ld: kexec.c:(.text+0x5c0): undefined reference to `crashk_low_res'
==========

On the provided config, it has:
===
CONFIG_VMCORE_INFO=y
CONFIG_KEXEC_CORE=y
CONFIG_KEXEC=y
CONFIG_KEXEC_FILE=y
===

For these crash related code blocks, they need put inside CONFIG_CRASH_DUMP
ifdeffery scope to avoid building erorr when CONFIG_CRASH_DUMP is not
set.

Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/all/20240126045551.GA126645@dev-arch.thelio-3990X/T/#u
Signed-off-by: Baoquan He <bhe@redhat.com>
---
 drivers/of/kexec.c  | 2 ++
 kernel/kexec_file.c | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
index 68278340cecf..9ccde2fd77cb 100644
--- a/drivers/of/kexec.c
+++ b/drivers/of/kexec.c
@@ -395,6 +395,7 @@ void *of_kexec_alloc_and_setup_fdt(const struct kimage *image,
 		if (ret)
 			goto out;
 
+#ifdef CONFIG_CRASH_DUMP
 		/* add linux,usable-memory-range */
 		ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
 				"linux,usable-memory-range", crashk_res.start,
@@ -410,6 +411,7 @@ void *of_kexec_alloc_and_setup_fdt(const struct kimage *image,
 			if (ret)
 				goto out;
 		}
+#endif
 	}
 
 	/* add bootargs */
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index ce7ce2ae27cd..2d1db05fbf04 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -540,8 +540,10 @@ static int kexec_walk_memblock(struct kexec_buf *kbuf,
 	phys_addr_t mstart, mend;
 	struct resource res = { };
 
+#ifdef CONFIG_CRASH_DUMP
 	if (kbuf->image->type == KEXEC_TYPE_CRASH)
 		return func(&crashk_res, kbuf);
+#endif
 
 	/*
 	 * Using MEMBLOCK_NONE will properly skip MEMBLOCK_DRIVER_MANAGED. See
-- 
2.41.0