1 files changed, 67 insertions, 0 deletions
diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h
new file mode 100644
index 00000000000..0026f267da2
--- /dev/null
+++ b/include/linux/crash_dump.h
@@ -0,0 +1,67 @@
+#ifndef LINUX_CRASH_DUMP_H
+#define LINUX_CRASH_DUMP_H
+
+#ifdef CONFIG_CRASH_DUMP
+#include <linux/kexec.h>
+#include <linux/device.h>
+#include <linux/proc_fs.h>
+
+#define ELFCORE_ADDR_MAX	(-1ULL)
+#define ELFCORE_ADDR_ERR	(-2ULL)
+
+extern unsigned long long elfcorehdr_addr;
+
+extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
+						unsigned long, int);
+
+/* Architecture code defines this if there are other possible ELF
+ * machine types, e.g. on bi-arch capable hardware. */
+#ifndef vmcore_elf_check_arch_cross
+#define vmcore_elf_check_arch_cross(x) 0
+#endif
+
+#define vmcore_elf_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
+
+/*
+ * is_kdump_kernel() checks whether this kernel is booting after a panic of
+ * previous kernel or not. This is determined by checking if previous kernel
+ * has passed the elf core header address on command line.
+ *
+ * This is not just a test if CONFIG_CRASH_DUMP is enabled or not. It will
+ * return 1 if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic of
+ * previous kernel.
+ */
+
+static inline int is_kdump_kernel(void)
+{
+	return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0;
+}
+
+/* is_vmcore_usable() checks if the kernel is booting after a panic and
+ * the vmcore region is usable.
+ *
+ * This makes use of the fact that due to alignment -2ULL is not
+ * a valid pointer, much in the vain of IS_ERR(), except
+ * dealing directly with an unsigned long long rather than a pointer.
+ */
+
+static inline int is_vmcore_usable(void)
+{
+	return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
+}
+
+/* vmcore_unusable() marks the vmcore as unusable,
+ * without disturbing the logic of is_kdump_kernel()
+ */
+
+static inline void vmcore_unusable(void)
+{
+	if (is_kdump_kernel())
+		elfcorehdr_addr = ELFCORE_ADDR_ERR;
+}
+#else /* !CONFIG_CRASH_DUMP */
+static inline int is_kdump_kernel(void) { return 0; }
+#endif /* CONFIG_CRASH_DUMP */
+
+extern unsigned long saved_max_pfn;
+#endif /* LINUX_CRASHDUMP_H */