crash: split crash dumping code out from kexec_core.c

Currently, KEXEC_CORE select CRASH_CORE automatically because crash codes
need be built in to avoid compiling error when building kexec code even
though the crash dumping functionality is not enabled. E.g
--------------------
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_KEXEC=y
CONFIG_KEXEC_FILE=y
---------------------

After splitting out crashkernel reservation code and vmcoreinfo exporting
code, there's only crash related code left in kernel/crash_core.c. Now
move crash related codes from kexec_core.c to crash_core.c and only build it
in when CONFIG_CRASH_DUMP=y.

And also wrap up crash codes inside CONFIG_CRASH_DUMP ifdeffery scope,
or replace inappropriate CONFIG_KEXEC_CORE ifdef with CONFIG_CRASH_DUMP
ifdef in generic kernel files.

With these changes, crash_core codes are abstracted from kexec codes and
can be disabled at all if only kexec reboot feature is wanted.

Link: https://lkml.kernel.org/r/20240124051254.67105-5-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
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>

1 files changed, 61 insertions, 0 deletions

diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index 7f19f62018ef..23270b16e1db 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -6,6 +6,48 @@
 #include <linux/elfcore.h>
 #include <linux/elf.h>
 
+struct kimage;
+
+#ifdef CONFIG_CRASH_DUMP
+
+int crash_shrink_memory(unsigned long new_size);
+ssize_t crash_get_memory_size(void);
+
+#ifndef arch_kexec_protect_crashkres
+/*
+ * Protection mechanism for crashkernel reserved memory after
+ * the kdump kernel is loaded.
+ *
+ * Provide an empty default implementation here -- architecture
+ * code may override this
+ */
+static inline void arch_kexec_protect_crashkres(void) { }
+#endif
+
+#ifndef arch_kexec_unprotect_crashkres
+static inline void arch_kexec_unprotect_crashkres(void) { }
+#endif
+
+
+
+#ifndef arch_crash_handle_hotplug_event
+static inline void arch_crash_handle_hotplug_event(struct kimage *image) { }
+#endif
+
+int crash_check_update_elfcorehdr(void);
+
+#ifndef crash_hotplug_cpu_support
+static inline int crash_hotplug_cpu_support(void) { return 0; }
+#endif
+
+#ifndef crash_hotplug_memory_support
+static inline int crash_hotplug_memory_support(void) { return 0; }
+#endif
+
+#ifndef crash_get_elfcorehdr_size
+static inline unsigned int crash_get_elfcorehdr_size(void) { return 0; }
+#endif
+
 /* Alignment required for elf header segment */
 #define ELF_CORE_HEADER_ALIGN   4096
 
@@ -31,4 +73,23 @@ struct kexec_segment;
 #define KEXEC_CRASH_HP_REMOVE_MEMORY		4
 #define KEXEC_CRASH_HP_INVALID_CPU		-1U
 
+extern void __crash_kexec(struct pt_regs *regs);
+extern void crash_kexec(struct pt_regs *regs);
+int kexec_should_crash(struct task_struct *p);
+int kexec_crash_loaded(void);
+void crash_save_cpu(struct pt_regs *regs, int cpu);
+extern int kimage_crash_copy_vmcoreinfo(struct kimage *image);
+
+#else /* !CONFIG_CRASH_DUMP*/
+struct pt_regs;
+struct task_struct;
+struct kimage;
+static inline void __crash_kexec(struct pt_regs *regs) { }
+static inline void crash_kexec(struct pt_regs *regs) { }
+static inline int kexec_should_crash(struct task_struct *p) { return 0; }
+static inline int kexec_crash_loaded(void) { return 0; }
+static inline void crash_save_cpu(struct pt_regs *regs, int cpu) {};
+static inline int kimage_crash_copy_vmcoreinfo(struct kimage *image) { return 0; };
+#endif /* CONFIG_CRASH_DUMP*/
+
 #endif /* LINUX_CRASH_CORE_H */