1 files changed, 147 insertions, 0 deletions
diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h
new file mode 100644
index 000000000..0f3a65629
--- /dev/null
+++ b/include/linux/crash_dump.h
@@ -0,0 +1,147 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef LINUX_CRASH_DUMP_H
+#define LINUX_CRASH_DUMP_H
+
+#include <linux/kexec.h>
+#include <linux/proc_fs.h>
+#include <linux/elf.h>
+#include <linux/pgtable.h>
+#include <uapi/linux/vmcore.h>
+
+/* For IS_ENABLED(CONFIG_CRASH_DUMP) */
+#define ELFCORE_ADDR_MAX	(-1ULL)
+#define ELFCORE_ADDR_ERR	(-2ULL)
+
+extern unsigned long long elfcorehdr_addr;
+extern unsigned long long elfcorehdr_size;
+
+#ifdef CONFIG_CRASH_DUMP
+extern int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size);
+extern void elfcorehdr_free(unsigned long long addr);
+extern ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos);
+extern ssize_t elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos);
+extern int remap_oldmem_pfn_range(struct vm_area_struct *vma,
+				  unsigned long from, unsigned long pfn,
+				  unsigned long size, pgprot_t prot);
+
+ssize_t copy_oldmem_page(struct iov_iter *i, unsigned long pfn, size_t csize,
+		unsigned long offset);
+ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn,
+				   size_t csize, unsigned long offset);
+
+void vmcore_cleanup(void);
+
+/* 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
+
+/*
+ * Architecture code can redefine this if there are any special checks
+ * needed for 32-bit ELF or 64-bit ELF vmcores.  In case of 32-bit
+ * only architecture, vmcore_elf64_check_arch can be set to zero.
+ */
+#ifndef vmcore_elf32_check_arch
+#define vmcore_elf32_check_arch(x) elf_check_arch(x)
+#endif
+
+#ifndef vmcore_elf64_check_arch
+#define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
+#endif
+
+/*
+ * 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 true if CONFIG_CRASH_DUMP=y and if kernel is booting after a panic
+ * of previous kernel.
+ */
+
+static inline bool is_kdump_kernel(void)
+{
+	return elfcorehdr_addr != ELFCORE_ADDR_MAX;
+}
+
+/* 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;
+}
+
+/**
+ * struct vmcore_cb - driver callbacks for /proc/vmcore handling
+ * @pfn_is_ram: check whether a PFN really is RAM and should be accessed when
+ *              reading the vmcore. Will return "true" if it is RAM or if the
+ *              callback cannot tell. If any callback returns "false", it's not
+ *              RAM and the page must not be accessed; zeroes should be
+ *              indicated in the vmcore instead. For example, a ballooned page
+ *              contains no data and reading from such a page will cause high
+ *              load in the hypervisor.
+ * @next: List head to manage registered callbacks internally; initialized by
+ *        register_vmcore_cb().
+ *
+ * vmcore callbacks allow drivers managing physical memory ranges to
+ * coordinate with vmcore handling code, for example, to prevent accessing
+ * physical memory ranges that should not be accessed when reading the vmcore,
+ * although included in the vmcore header as memory ranges to dump.
+ */
+struct vmcore_cb {
+	bool (*pfn_is_ram)(struct vmcore_cb *cb, unsigned long pfn);
+	struct list_head next;
+};
+extern void register_vmcore_cb(struct vmcore_cb *cb);
+extern void unregister_vmcore_cb(struct vmcore_cb *cb);
+
+#else /* !CONFIG_CRASH_DUMP */
+static inline bool is_kdump_kernel(void) { return false; }
+#endif /* CONFIG_CRASH_DUMP */
+
+/* Device Dump information to be filled by drivers */
+struct vmcoredd_data {
+	char dump_name[VMCOREDD_MAX_NAME_BYTES]; /* Unique name of the dump */
+	unsigned int size;                       /* Size of the dump */
+	/* Driver's registered callback to be invoked to collect dump */
+	int (*vmcoredd_callback)(struct vmcoredd_data *data, void *buf);
+};
+
+#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
+int vmcore_add_device_dump(struct vmcoredd_data *data);
+#else
+static inline int vmcore_add_device_dump(struct vmcoredd_data *data)
+{
+	return -EOPNOTSUPP;
+}
+#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
+
+#ifdef CONFIG_PROC_VMCORE
+ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
+			 u64 *ppos, bool encrypted);
+#else
+static inline ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
+				       u64 *ppos, bool encrypted)
+{
+	return -EOPNOTSUPP;
+}
+#endif /* CONFIG_PROC_VMCORE */
+
+#endif /* LINUX_CRASHDUMP_H */