crash: split vmcoreinfo exporting code out from crash_core.c

Now move the relevant codes into separate files:
kernel/crash_reserve.c, include/linux/crash_reserve.h.

And add config item CRASH_RESERVE to control its enabling.

And also update the old ifdeffery of CONFIG_CRASH_CORE, including of
<linux/crash_core.h> and config item dependency on CRASH_CORE
accordingly.

And also do renaming as follows:
 - arch/xxx/kernel/{crash_core.c => vmcore_info.c}
because they are only related to vmcoreinfo exporting on x86, arm64,
riscv.

And also Remove config item CRASH_CORE, and rely on CONFIG_KEXEC_CORE to
decide if build in crash_core.c.

[yang.lee@linux.alibaba.com: remove duplicated include in vmcore_info.c]
  Link: https://lkml.kernel.org/r/20240126005744.16561-1-yang.lee@linux.alibaba.com
Link: https://lkml.kernel.org/r/20240124051254.67105-3-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.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, 81 insertions, 0 deletions

diff --git a/include/linux/vmcore_info.h b/include/linux/vmcore_info.h
new file mode 100644
index 000000000000..e1dec1a6a749
--- /dev/null
+++ b/include/linux/vmcore_info.h
@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef LINUX_VMCORE_INFO_H
+#define LINUX_VMCORE_INFO_H
+
+#include <linux/linkage.h>
+#include <linux/elfcore.h>
+#include <linux/elf.h>
+
+#define CRASH_CORE_NOTE_NAME	   "CORE"
+#define CRASH_CORE_NOTE_HEAD_BYTES ALIGN(sizeof(struct elf_note), 4)
+#define CRASH_CORE_NOTE_NAME_BYTES ALIGN(sizeof(CRASH_CORE_NOTE_NAME), 4)
+#define CRASH_CORE_NOTE_DESC_BYTES ALIGN(sizeof(struct elf_prstatus), 4)
+
+/*
+ * The per-cpu notes area is a list of notes terminated by a "NULL"
+ * note header.  For kdump, the code in vmcore.c runs in the context
+ * of the second kernel to combine them into one note.
+ */
+#define CRASH_CORE_NOTE_BYTES	   ((CRASH_CORE_NOTE_HEAD_BYTES * 2) +	\
+				     CRASH_CORE_NOTE_NAME_BYTES +	\
+				     CRASH_CORE_NOTE_DESC_BYTES)
+
+#define VMCOREINFO_BYTES	   PAGE_SIZE
+#define VMCOREINFO_NOTE_NAME	   "VMCOREINFO"
+#define VMCOREINFO_NOTE_NAME_BYTES ALIGN(sizeof(VMCOREINFO_NOTE_NAME), 4)
+#define VMCOREINFO_NOTE_SIZE	   ((CRASH_CORE_NOTE_HEAD_BYTES * 2) +	\
+				     VMCOREINFO_NOTE_NAME_BYTES +	\
+				     VMCOREINFO_BYTES)
+
+typedef u32 note_buf_t[CRASH_CORE_NOTE_BYTES/4];
+/* Per cpu memory for storing cpu states in case of system crash. */
+extern note_buf_t __percpu *crash_notes;
+
+void crash_update_vmcoreinfo_safecopy(void *ptr);
+void crash_save_vmcoreinfo(void);
+void arch_crash_save_vmcoreinfo(void);
+__printf(1, 2)
+void vmcoreinfo_append_str(const char *fmt, ...);
+phys_addr_t paddr_vmcoreinfo_note(void);
+
+#define VMCOREINFO_OSRELEASE(value) \
+	vmcoreinfo_append_str("OSRELEASE=%s\n", value)
+#define VMCOREINFO_BUILD_ID()						\
+	({								\
+		static_assert(sizeof(vmlinux_build_id) == 20);		\
+		vmcoreinfo_append_str("BUILD-ID=%20phN\n", vmlinux_build_id); \
+	})
+
+#define VMCOREINFO_PAGESIZE(value) \
+	vmcoreinfo_append_str("PAGESIZE=%ld\n", value)
+#define VMCOREINFO_SYMBOL(name) \
+	vmcoreinfo_append_str("SYMBOL(%s)=%lx\n", #name, (unsigned long)&name)
+#define VMCOREINFO_SYMBOL_ARRAY(name) \
+	vmcoreinfo_append_str("SYMBOL(%s)=%lx\n", #name, (unsigned long)name)
+#define VMCOREINFO_SIZE(name) \
+	vmcoreinfo_append_str("SIZE(%s)=%lu\n", #name, \
+			      (unsigned long)sizeof(name))
+#define VMCOREINFO_STRUCT_SIZE(name) \
+	vmcoreinfo_append_str("SIZE(%s)=%lu\n", #name, \
+			      (unsigned long)sizeof(struct name))
+#define VMCOREINFO_OFFSET(name, field) \
+	vmcoreinfo_append_str("OFFSET(%s.%s)=%lu\n", #name, #field, \
+			      (unsigned long)offsetof(struct name, field))
+#define VMCOREINFO_TYPE_OFFSET(name, field) \
+	vmcoreinfo_append_str("OFFSET(%s.%s)=%lu\n", #name, #field, \
+			      (unsigned long)offsetof(name, field))
+#define VMCOREINFO_LENGTH(name, value) \
+	vmcoreinfo_append_str("LENGTH(%s)=%lu\n", #name, (unsigned long)value)
+#define VMCOREINFO_NUMBER(name) \
+	vmcoreinfo_append_str("NUMBER(%s)=%ld\n", #name, (long)name)
+#define VMCOREINFO_CONFIG(name) \
+	vmcoreinfo_append_str("CONFIG_%s=y\n", #name)
+
+extern unsigned char *vmcoreinfo_data;
+extern size_t vmcoreinfo_size;
+extern u32 *vmcoreinfo_note;
+
+Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
+			  void *data, size_t data_len);
+void final_note(Elf_Word *buf);
+#endif /* LINUX_VMCORE_INFO_H */