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().

[[e-mail]: remove stray newlines at eof]
Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Baoquan He <[e-mail]>
Reported-by: Nathan Chancellor <[e-mail]>
Closes: https://lore.kernel.org/all/[e-mail]-3990X/T/#u
Cc: Al Viro <[e-mail]>
Cc: Eric W. Biederman <[e-mail]>
Cc: Hari Bathini <[e-mail]>
Cc: Klara Modin <[e-mail]>
Cc: Michael Kelley <[e-mail]>
Cc: Pingfan Liu <[e-mail]>
Cc: Stephen Rothwell <[e-mail]>
Cc: Yang Li <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

arch/arm/kernel/Makefile

···
 obj-$(CONFIG_FUNCTION_GRAPH_TRACER)	+= ftrace.o insn.o patch.o
 obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o insn.o patch.o
 obj-$(CONFIG_KEXEC_CORE)	+= machine_kexec.o relocate_kernel.o
+obj-$(CONFIG_VMCORE_INFO)	+= vmcore_info.o
 # Main staffs in KPROBES are in arch/arm/probes/ .
 obj-$(CONFIG_KPROBES)		+= patch.o insn.o
 obj-$(CONFIG_OABI_COMPAT)	+= sys_oabi-compat.o

arch/arm/kernel/machine_kexec.c

···
 
 	soft_restart(reboot_entry_phys);
 }
-
-void arch_crash_save_vmcoreinfo(void)
-{
-#ifdef CONFIG_ARM_LPAE
-	VMCOREINFO_CONFIG(ARM_LPAE);
-#endif
-}

arch/arm/kernel/vmcore_info.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/vmcore_info.h>
+
+void arch_crash_save_vmcoreinfo(void)
+{
+#ifdef CONFIG_ARM_LPAE
+	VMCOREINFO_CONFIG(ARM_LPAE);
+#endif
+}

arch/powerpc/kexec/Makefile

···
 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

arch/powerpc/kexec/core.c

···
 {
 }
 
-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.

arch/powerpc/kexec/vmcore_info.c

···
+// 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());
+}

arch/s390/kernel/Makefile

···
 obj-$(CONFIG_FUNCTION_TRACER)	+= mcount.o
 obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
 obj-$(CONFIG_KEXEC_CORE)	+= machine_kexec.o relocate_kernel.o
+obj-$(CONFIG_VMCORE_INFO)	+= vmcore_info.o
 obj-$(CONFIG_UPROBES)		+= uprobes.o
 obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o
 

arch/s390/kernel/machine_kexec.c

···
 {
 }
 
-void arch_crash_save_vmcoreinfo(void)
-{
-	struct lowcore *abs_lc;
-
-	VMCOREINFO_SYMBOL(lowcore_ptr);
-	VMCOREINFO_SYMBOL(high_memory);
-	VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
-	vmcoreinfo_append_str("SAMODE31=%lx\n", (unsigned long)__samode31);
-	vmcoreinfo_append_str("EAMODE31=%lx\n", (unsigned long)__eamode31);
-	vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
-	abs_lc = get_abs_lowcore();
-	abs_lc->vmcore_info = paddr_vmcoreinfo_note();
-	put_abs_lowcore(abs_lc);
-}
-
 void machine_shutdown(void)
 {
 }

arch/s390/kernel/vmcore_info.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/vmcore_info.h>
+#include <asm/abs_lowcore.h>
+#include <linux/mm.h>
+#include <asm/setup.h>
+
+void arch_crash_save_vmcoreinfo(void)
+{
+	struct lowcore *abs_lc;
+
+	VMCOREINFO_SYMBOL(lowcore_ptr);
+	VMCOREINFO_SYMBOL(high_memory);
+	VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
+	vmcoreinfo_append_str("SAMODE31=%lx\n", (unsigned long)__samode31);
+	vmcoreinfo_append_str("EAMODE31=%lx\n", (unsigned long)__eamode31);
+	vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
+	abs_lc = get_abs_lowcore();
+	abs_lc->vmcore_info = paddr_vmcoreinfo_note();
+	put_abs_lowcore(abs_lc);
+}

arch/sh/kernel/Makefile

···
 obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_MODULES)		+= sh_ksyms_32.o module.o
 obj-$(CONFIG_KEXEC_CORE)	+= machine_kexec.o relocate_kernel.o
+obj-$(CONFIG_VMCORE_INFO)	+= vmcore_info.o
 obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
 obj-$(CONFIG_STACKTRACE)	+= stacktrace.o
 obj-$(CONFIG_IO_TRAPPED)	+= io_trapped.o

arch/sh/kernel/machine_kexec.c

···
 	__ftrace_enabled_restore(save_ftrace_enabled);
 }
 
-void arch_crash_save_vmcoreinfo(void)
-{
-#ifdef CONFIG_NUMA
-	VMCOREINFO_SYMBOL(node_data);
-	VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
-#endif
-#ifdef CONFIG_X2TLB
-	VMCOREINFO_CONFIG(X2TLB);
-#endif
-}
-
 void __init reserve_crashkernel(void)
 {
 	unsigned long long crash_size, crash_base;

arch/sh/kernel/vmcore_info.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/vmcore_info.h>
+#include <linux/mm.h>
+
+void arch_crash_save_vmcoreinfo(void)
+{
+#ifdef CONFIG_NUMA
+	VMCOREINFO_SYMBOL(node_data);
+	VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
+#endif
+#ifdef CONFIG_X2TLB
+	VMCOREINFO_CONFIG(X2TLB);
+#endif
+}