arch, crash: move arch_crash_save_vmcoreinfo() out to file vmcore_info.c

Nathan reported below building error:

=====
$ curl -LSso .config https://git.alpinelinux.org/aports/plain/community/linux-edge/config-edge.armv7
$ make -skj"$(nproc)" ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- olddefconfig all
..
arm-linux-gnueabi-ld: arch/arm/kernel/machine_kexec.o: in function `arch_crash_save_vmcoreinfo':
machine_kexec.c:(.text+0x488): undefined reference to `vmcoreinfo_append_str'
====

On architecutres, like arm, s390, ppc, sh, function
arch_crash_save_vmcoreinfo() is located in machine_kexec.c and it can
only be compiled in when CONFIG_KEXEC_CORE=y.

That's not right because arch_crash_save_vmcoreinfo() is used to export
arch specific vmcoreinfo. CONFIG_VMCORE_INFO is supposed to control its
compiling in. However, CONFIG_VMVCORE_INFO could be independent of
CONFIG_KEXEC_CORE, e.g CONFIG_PROC_KCORE=y will select CONFIG_VMVCORE_INFO.
Or CONFIG_KEXEC/CONFIG_KEXEC_FILE is set while CONFIG_CRASH_DUMP is
not set, it will report linking error.

So, on arm, s390, ppc and sh, move arch_crash_save_vmcoreinfo out to
a new file vmcore_info.c. Let CONFIG_VMCORE_INFO decide if compiling in
arch_crash_save_vmcoreinfo().

[akpm@linux-foundation.org: remove stray newlines at eof]
Link: https://lkml.kernel.org/r/20240129135033.157195-3-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/all/20240126045551.GA126645@dev-arch.thelio-3990X/T/#u
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

3 files changed, 33 insertions, 28 deletions

diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
index 0c2abe7f9908..91e96f5168b7 100644
--- a/arch/powerpc/kexec/Makefile
+++ b/arch/powerpc/kexec/Makefile
@@ -8,6 +8,7 @@ obj-y				+= core.o crash.o core_$(BITS).o
 obj-$(CONFIG_PPC32)		+= relocate_32.o
 
 obj-$(CONFIG_KEXEC_FILE)	+= file_load.o ranges.o file_load_$(BITS).o elf_$(BITS).o
+obj-$(CONFIG_VMCORE_INFO)	+= vmcore_info.o
 
 # Disable GCOV, KCOV & sanitizers in odd or sensitive code
 GCOV_PROFILE_core_$(BITS).o := n
diff --git a/arch/powerpc/kexec/core.c b/arch/powerpc/kexec/core.c
index 27fa9098a5b7..3ff4411ed496 100644
--- a/arch/powerpc/kexec/core.c
+++ b/arch/powerpc/kexec/core.c
@@ -53,34 +53,6 @@ void machine_kexec_cleanup(struct kimage *image)
 {
 }
 
-void arch_crash_save_vmcoreinfo(void)
-{
-
-#ifdef CONFIG_NUMA
-	VMCOREINFO_SYMBOL(node_data);
-	VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
-#endif
-#ifndef CONFIG_NUMA
-	VMCOREINFO_SYMBOL(contig_page_data);
-#endif
-#if defined(CONFIG_PPC64) && defined(CONFIG_SPARSEMEM_VMEMMAP)
-	VMCOREINFO_SYMBOL(vmemmap_list);
-	VMCOREINFO_SYMBOL(mmu_vmemmap_psize);
-	VMCOREINFO_SYMBOL(mmu_psize_defs);
-	VMCOREINFO_STRUCT_SIZE(vmemmap_backing);
-	VMCOREINFO_OFFSET(vmemmap_backing, list);
-	VMCOREINFO_OFFSET(vmemmap_backing, phys);
-	VMCOREINFO_OFFSET(vmemmap_backing, virt_addr);
-	VMCOREINFO_STRUCT_SIZE(mmu_psize_def);
-	VMCOREINFO_OFFSET(mmu_psize_def, shift);
-#endif
-	VMCOREINFO_SYMBOL(cur_cpu_spec);
-	VMCOREINFO_OFFSET(cpu_spec, cpu_features);
-	VMCOREINFO_OFFSET(cpu_spec, mmu_features);
-	vmcoreinfo_append_str("NUMBER(RADIX_MMU)=%d\n", early_radix_enabled());
-	vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
-}
-
 /*
  * Do not allocate memory (or fail in any way) in machine_kexec().
  * We are past the point of no return, committed to rebooting now.
diff --git a/arch/powerpc/kexec/vmcore_info.c b/arch/powerpc/kexec/vmcore_info.c
new file mode 100644
index 000000000000..2b65d2adca5e
--- /dev/null
+++ b/arch/powerpc/kexec/vmcore_info.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/vmcore_info.h>
+#include <asm/pgalloc.h>
+
+void arch_crash_save_vmcoreinfo(void)
+{
+
+#ifdef CONFIG_NUMA
+	VMCOREINFO_SYMBOL(node_data);
+	VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
+#endif
+#ifndef CONFIG_NUMA
+	VMCOREINFO_SYMBOL(contig_page_data);
+#endif
+#if defined(CONFIG_PPC64) && defined(CONFIG_SPARSEMEM_VMEMMAP)
+	VMCOREINFO_SYMBOL(vmemmap_list);
+	VMCOREINFO_SYMBOL(mmu_vmemmap_psize);
+	VMCOREINFO_SYMBOL(mmu_psize_defs);
+	VMCOREINFO_STRUCT_SIZE(vmemmap_backing);
+	VMCOREINFO_OFFSET(vmemmap_backing, list);
+	VMCOREINFO_OFFSET(vmemmap_backing, phys);
+	VMCOREINFO_OFFSET(vmemmap_backing, virt_addr);
+	VMCOREINFO_STRUCT_SIZE(mmu_psize_def);
+	VMCOREINFO_OFFSET(mmu_psize_def, shift);
+#endif
+	VMCOREINFO_SYMBOL(cur_cpu_spec);
+	VMCOREINFO_OFFSET(cpu_spec, cpu_features);
+	VMCOREINFO_OFFSET(cpu_spec, mmu_features);
+	vmcoreinfo_append_str("NUMBER(RADIX_MMU)=%d\n", early_radix_enabled());
+	vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
+}