1 files changed, 35 insertions, 20 deletions

diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h
index 4664fc1871de..0f3a656293b0 100644
--- a/include/linux/crash_dump.h
+++ b/include/linux/crash_dump.h
@@ -5,17 +5,17 @@
 #include <linux/kexec.h>
 #include <linux/proc_fs.h>
 #include <linux/elf.h>
+#include <linux/pgtable.h>
 #include <uapi/linux/vmcore.h>
 
-#include <asm/pgtable.h> /* for pgprot_t */
-
-#ifdef CONFIG_CRASH_DUMP
+/* 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);
@@ -24,11 +24,10 @@ extern int remap_oldmem_pfn_range(struct vm_area_struct *vma,
 				  unsigned long from, unsigned long pfn,
 				  unsigned long size, pgprot_t prot);
 
-extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
-						unsigned long, int);
-extern ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf,
-					  size_t csize, unsigned long offset,
-					  int userbuf);
+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);
 
@@ -89,16 +88,34 @@ static inline void vmcore_unusable(void)
 		elfcorehdr_addr = ELFCORE_ADDR_ERR;
 }
 
-#define HAVE_OLDMEM_PFN_IS_RAM 1
-extern int register_oldmem_pfn_is_ram(int (*fn)(unsigned long pfn));
-extern void unregister_oldmem_pfn_is_ram(void);
+/**
+ * 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 0; }
+static inline bool is_kdump_kernel(void) { return false; }
 #endif /* CONFIG_CRASH_DUMP */
 
-extern unsigned long saved_max_pfn;
-
 /* Device Dump information to be filled by drivers */
 struct vmcoredd_data {
 	char dump_name[VMCOREDD_MAX_NAME_BYTES]; /* Unique name of the dump */
@@ -117,13 +134,11 @@ static inline int vmcore_add_device_dump(struct vmcoredd_data *data)
 #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
 
 #ifdef CONFIG_PROC_VMCORE
-ssize_t read_from_oldmem(char *buf, size_t count,
-			 u64 *ppos, int userbuf,
-			 bool encrypted);
+ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
+			 u64 *ppos, bool encrypted);
 #else
-static inline ssize_t read_from_oldmem(char *buf, size_t count,
-				       u64 *ppos, int userbuf,
-				       bool encrypted)
+static inline ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
+				       u64 *ppos, bool encrypted)
 {
 	return -EOPNOTSUPP;
 }