Merge tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:

 - "panic: sys_info: Refactor and fix a potential issue" (Andy Shevchenko)
   fixes a build issue and does some cleanup in ib/sys_info.c

 - "Implement mul_u64_u64_div_u64_roundup()" (David Laight)
   enhances the 64-bit math code on behalf of a PWM driver and beefs up
   the test module for these library functions

 - "scripts/gdb/symbols: make BPF debug info available to GDB" (Ilya Leoshkevich)
   makes BPF symbol names, sizes, and line numbers available to the GDB
   debugger

 - "Enable hung_task and lockup cases to dump system info on demand" (Feng Tang)
   adds a sysctl which can be used to cause additional info dumping when
   the hung-task and lockup detectors fire

 - "lib/base64: add generic encoder/decoder, migrate users" (Kuan-Wei Chiu)
   adds a general base64 encoder/decoder to lib/ and migrates several
   users away from their private implementations

 - "rbree: inline rb_first() and rb_last()" (Eric Dumazet)
   makes TCP a little faster

 - "liveupdate: Rework KHO for in-kernel users" (Pasha Tatashin)
   reworks the KEXEC Handover interfaces in preparation for Live Update
   Orchestrator (LUO), and possibly for other future clients

 - "kho: simplify state machine and enable dynamic updates" (Pasha Tatashin)
   increases the flexibility of KEXEC Handover. Also preparation for LUO

 - "Live Update Orchestrator" (Pasha Tatashin)
   is a major new feature targeted at cloud environments. Quoting the
   cover letter:

      This series introduces the Live Update Orchestrator, a kernel
      subsystem designed to facilitate live kernel updates using a
      kexec-based reboot. This capability is critical for cloud
      environments, allowing hypervisors to be updated with minimal
      downtime for running virtual machines. LUO achieves this by
      preserving the state of selected resources, such as memory,
      devices and their dependencies, across the kernel transition.

      As a key feature, this series includes support for preserving
      memfd file descriptors, which allows critical in-memory data, such
      as guest RAM or any other large memory region, to be maintained in
      RAM across the kexec reboot.

   Mike Rappaport merits a mention here, for his extensive review and
   testing work.

 - "kexec: reorganize kexec and kdump sysfs" (Sourabh Jain)
   moves the kexec and kdump sysfs entries from /sys/kernel/ to
   /sys/kernel/kexec/ and adds back-compatibility symlinks which can
   hopefully be removed one day

 - "kho: fixes for vmalloc restoration" (Mike Rapoport)
   fixes a BUG which was being hit during KHO restoration of vmalloc()
   regions

* tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (139 commits)
  calibrate: update header inclusion
  Reinstate "resource: avoid unnecessary lookups in find_next_iomem_res()"
  vmcoreinfo: track and log recoverable hardware errors
  kho: fix restoring of contiguous ranges of order-0 pages
  kho: kho_restore_vmalloc: fix initialization of pages array
  MAINTAINERS: TPM DEVICE DRIVER: update the W-tag
  init: replace simple_strtoul with kstrtoul to improve lpj_setup
  KHO: fix boot failure due to kmemleak access to non-PRESENT pages
  Documentation/ABI: new kexec and kdump sysfs interface
  Documentation/ABI: mark old kexec sysfs deprecated
  kexec: move sysfs entries to /sys/kernel/kexec
  test_kho: always print restore status
  kho: free chunks using free_page() instead of kfree()
  selftests/liveupdate: add kexec test for multiple and empty sessions
  selftests/liveupdate: add simple kexec-based selftest for LUO
  selftests/liveupdate: add userspace API selftests
  docs: add documentation for memfd preservation via LUO
  mm: memfd_luo: allow preserving memfd
  liveupdate: luo_file: add private argument to store runtime state
  mm: shmem: export some functions to internal.h
  ...

19 files changed, 574 insertions, 99 deletions

diff --git a/include/linux/base64.h b/include/linux/base64.h
index 660d4cb1ef31..a2c6c9222da3 100644
--- a/include/linux/base64.h
+++ b/include/linux/base64.h
@@ -8,9 +8,15 @@
 
 #include <linux/types.h>
 
+enum base64_variant {
+	BASE64_STD,       /* RFC 4648 (standard) */
+	BASE64_URLSAFE,   /* RFC 4648 (base64url) */
+	BASE64_IMAP,      /* RFC 3501 */
+};
+
 #define BASE64_CHARS(nbytes)   DIV_ROUND_UP((nbytes) * 4, 3)
 
-int base64_encode(const u8 *src, int len, char *dst);
-int base64_decode(const char *src, int len, u8 *dst);
+int base64_encode(const u8 *src, int len, char *dst, bool padding, enum base64_variant variant);
+int base64_decode(const char *src, int len, u8 *dst, bool padding, enum base64_variant variant);
 
 #endif /* _LINUX_BASE64_H */
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index ab181d87d71d..ff71bebe56f5 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -273,12 +273,6 @@ static inline void *offset_to_ptr(const int *off)
 
 #endif /* __ASSEMBLY__ */
 
-#ifdef CONFIG_64BIT
-#define ARCH_SEL(a,b) a
-#else
-#define ARCH_SEL(a,b) b
-#endif
-
 /*
  * Force the compiler to emit 'sym' as a symbol, so that we can reference
  * it from inline assembler. Necessary in case 'sym' could be inlined
diff --git a/include/linux/crash_reserve.h b/include/linux/crash_reserve.h
index 7b44b41d0a20..f0dc03d94ca2 100644
--- a/include/linux/crash_reserve.h
+++ b/include/linux/crash_reserve.h
@@ -32,6 +32,12 @@ int __init parse_crashkernel(char *cmdline, unsigned long long system_ram,
 void __init reserve_crashkernel_cma(unsigned long long cma_size);
 
 #ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
+#ifndef arch_add_crash_res_to_iomem
+static inline bool arch_add_crash_res_to_iomem(void)
+{
+	return true;
+}
+#endif
 #ifndef DEFAULT_CRASH_KERNEL_LOW_SIZE
 #define DEFAULT_CRASH_KERNEL_LOW_SIZE	(128UL << 20)
 #endif
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index ff44ec346162..05743900a116 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -38,11 +38,12 @@ struct _ddebug {
 #define _DPRINTK_FLAGS_INCL_LINENO	(1<<3)
 #define _DPRINTK_FLAGS_INCL_TID		(1<<4)
 #define _DPRINTK_FLAGS_INCL_SOURCENAME	(1<<5)
+#define _DPRINTK_FLAGS_INCL_STACK	(1<<6)
 
 #define _DPRINTK_FLAGS_INCL_ANY		\
 	(_DPRINTK_FLAGS_INCL_MODNAME | _DPRINTK_FLAGS_INCL_FUNCNAME |\
 	 _DPRINTK_FLAGS_INCL_LINENO  | _DPRINTK_FLAGS_INCL_TID |\
-	 _DPRINTK_FLAGS_INCL_SOURCENAME)
+	 _DPRINTK_FLAGS_INCL_SOURCENAME | _DPRINTK_FLAGS_INCL_STACK)
 
 #if defined DEBUG
 #define _DPRINTK_FLAGS_DEFAULT _DPRINTK_FLAGS_PRINT
@@ -160,6 +161,12 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 			 const struct ib_device *ibdev,
 			 const char *fmt, ...);
 
+#define __dynamic_dump_stack(desc)				\
+{								\
+	if (desc.flags & _DPRINTK_FLAGS_INCL_STACK)		\
+		dump_stack();					\
+}
+
 #define DEFINE_DYNAMIC_DEBUG_METADATA_CLS(name, cls, fmt)	\
 	static struct _ddebug  __aligned(8)			\
 	__section("__dyndbg") name = {				\
@@ -220,8 +227,10 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
  */
 #define __dynamic_func_call_cls(id, cls, fmt, func, ...) do {	\
 	DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt);	\
-	if (DYNAMIC_DEBUG_BRANCH(id))				\
+	if (DYNAMIC_DEBUG_BRANCH(id)) {				\
 		func(&id, ##__VA_ARGS__);			\
+		__dynamic_dump_stack(id);			\
+	}							\
 } while (0)
 #define __dynamic_func_call(id, fmt, func, ...)				\
 	__dynamic_func_call_cls(id, _DPRINTK_CLASS_DFLT, fmt,		\
@@ -229,8 +238,10 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor,
 
 #define __dynamic_func_call_cls_no_desc(id, cls, fmt, func, ...) do {	\
 	DEFINE_DYNAMIC_DEBUG_METADATA_CLS(id, cls, fmt);		\
-	if (DYNAMIC_DEBUG_BRANCH(id))					\
+	if (DYNAMIC_DEBUG_BRANCH(id)) {					\
 		func(__VA_ARGS__);					\
+		__dynamic_dump_stack(id);				\
+	}								\
 } while (0)
 #define __dynamic_func_call_no_desc(id, fmt, func, ...)			\
 	__dynamic_func_call_cls_no_desc(id, _DPRINTK_CLASS_DFLT,	\
diff --git a/include/linux/kexec_handover.h b/include/linux/kexec_handover.h
index 25042c1d8d54..5f7b9de97e8d 100644
--- a/include/linux/kexec_handover.h
+++ b/include/linux/kexec_handover.h
@@ -2,22 +2,16 @@
 #ifndef LINUX_KEXEC_HANDOVER_H
 #define LINUX_KEXEC_HANDOVER_H
 
-#include <linux/types.h>
+#include <linux/err.h>
 #include <linux/errno.h>
+#include <linux/types.h>
 
 struct kho_scratch {
 	phys_addr_t addr;
 	phys_addr_t size;
 };
 
-/* KHO Notifier index */
-enum kho_event {
-	KEXEC_KHO_FINALIZE = 0,
-	KEXEC_KHO_ABORT = 1,
-};
-
 struct folio;
-struct notifier_block;
 struct page;
 
 #define DECLARE_KHOSER_PTR(name, type) \
@@ -37,8 +31,6 @@ struct page;
 		(typeof((s).ptr))((s).phys ? phys_to_virt((s).phys) : NULL); \
 	})
 
-struct kho_serialization;
-
 struct kho_vmalloc_chunk;
 struct kho_vmalloc {
 	DECLARE_KHOSER_PTR(first, struct kho_vmalloc_chunk *);
@@ -52,17 +44,21 @@ bool kho_is_enabled(void);
 bool is_kho_boot(void);
 
 int kho_preserve_folio(struct folio *folio);
+void kho_unpreserve_folio(struct folio *folio);
 int kho_preserve_pages(struct page *page, unsigned int nr_pages);
+void kho_unpreserve_pages(struct page *page, unsigned int nr_pages);
 int kho_preserve_vmalloc(void *ptr, struct kho_vmalloc *preservation);
+void kho_unpreserve_vmalloc(struct kho_vmalloc *preservation);
+void *kho_alloc_preserve(size_t size);
+void kho_unpreserve_free(void *mem);
+void kho_restore_free(void *mem);
 struct folio *kho_restore_folio(phys_addr_t phys);
 struct page *kho_restore_pages(phys_addr_t phys, unsigned int nr_pages);
 void *kho_restore_vmalloc(const struct kho_vmalloc *preservation);
-int kho_add_subtree(struct kho_serialization *ser, const char *name, void *fdt);
+int kho_add_subtree(const char *name, void *fdt);
+void kho_remove_subtree(void *fdt);
 int kho_retrieve_subtree(const char *name, phys_addr_t *phys);
 
-int register_kho_notifier(struct notifier_block *nb);
-int unregister_kho_notifier(struct notifier_block *nb);
-
 void kho_memory_init(void);
 
 void kho_populate(phys_addr_t fdt_phys, u64 fdt_len, phys_addr_t scratch_phys,
@@ -83,17 +79,31 @@ static inline int kho_preserve_folio(struct folio *folio)
 	return -EOPNOTSUPP;
 }
 
+static inline void kho_unpreserve_folio(struct folio *folio) { }
+
 static inline int kho_preserve_pages(struct page *page, unsigned int nr_pages)
 {
 	return -EOPNOTSUPP;
 }
 
+static inline void kho_unpreserve_pages(struct page *page, unsigned int nr_pages) { }
+
 static inline int kho_preserve_vmalloc(void *ptr,
 				       struct kho_vmalloc *preservation)
 {
 	return -EOPNOTSUPP;
 }
 
+static inline void kho_unpreserve_vmalloc(struct kho_vmalloc *preservation) { }
+
+static inline void *kho_alloc_preserve(size_t size)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
+static inline void kho_unpreserve_free(void *mem) { }
+static inline void kho_restore_free(void *mem) { }
+
 static inline struct folio *kho_restore_folio(phys_addr_t phys)
 {
 	return NULL;
@@ -110,30 +120,19 @@ static inline void *kho_restore_vmalloc(const struct kho_vmalloc *preservation)
 	return NULL;
 }
 
-static inline int kho_add_subtree(struct kho_serialization *ser,
-				  const char *name, void *fdt)
-{
-	return -EOPNOTSUPP;
-}
-
-static inline int kho_retrieve_subtree(const char *name, phys_addr_t *phys)
+static inline int kho_add_subtree(const char *name, void *fdt)
 {
 	return -EOPNOTSUPP;
 }
 
-static inline int register_kho_notifier(struct notifier_block *nb)
-{
-	return -EOPNOTSUPP;
-}
+static inline void kho_remove_subtree(void *fdt) { }
 
-static inline int unregister_kho_notifier(struct notifier_block *nb)
+static inline int kho_retrieve_subtree(const char *name, phys_addr_t *phys)
 {
 	return -EOPNOTSUPP;
 }
 
-static inline void kho_memory_init(void)
-{
-}
+static inline void kho_memory_init(void) { }
 
 static inline void kho_populate(phys_addr_t fdt_phys, u64 fdt_len,
 				phys_addr_t scratch_phys, u64 scratch_len)
diff --git a/include/linux/kho/abi/luo.h b/include/linux/kho/abi/luo.h
new file mode 100644
index 000000000000..bb099c92e469
--- /dev/null
+++ b/include/linux/kho/abi/luo.h
@@ -0,0 +1,166 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Copyright (c) 2025, Google LLC.
+ * Pasha Tatashin <pasha.tatashin@soleen.com>
+ */
+
+/**
+ * DOC: Live Update Orchestrator ABI
+ *
+ * This header defines the stable Application Binary Interface used by the
+ * Live Update Orchestrator to pass state from a pre-update kernel to a
+ * post-update kernel. The ABI is built upon the Kexec HandOver framework
+ * and uses a Flattened Device Tree to describe the preserved data.
+ *
+ * This interface is a contract. Any modification to the FDT structure, node
+ * properties, compatible strings, or the layout of the `__packed` serialization
+ * structures defined here constitutes a breaking change. Such changes require
+ * incrementing the version number in the relevant `_COMPATIBLE` string to
+ * prevent a new kernel from misinterpreting data from an old kernel.
+ *
+ * Changes are allowed provided the compatibility version is incremented;
+ * however, backward/forward compatibility is only guaranteed for kernels
+ * supporting the same ABI version.
+ *
+ * FDT Structure Overview:
+ *   The entire LUO state is encapsulated within a single KHO entry named "LUO".
+ *   This entry contains an FDT with the following layout:
+ *
+ *   .. code-block:: none
+ *
+ *     / {
+ *         compatible = "luo-v1";
+ *         liveupdate-number = <...>;
+ *
+ *         luo-session {
+ *             compatible = "luo-session-v1";
+ *             luo-session-header = <phys_addr_of_session_header_ser>;
+ *         };
+ *     };
+ *
+ * Main LUO Node (/):
+ *
+ *   - compatible: "luo-v1"
+ *     Identifies the overall LUO ABI version.
+ *   - liveupdate-number: u64
+ *     A counter tracking the number of successful live updates performed.
+ *
+ * Session Node (luo-session):
+ *   This node describes all preserved user-space sessions.
+ *
+ *   - compatible: "luo-session-v1"
+ *     Identifies the session ABI version.
+ *   - luo-session-header: u64
+ *     The physical address of a `struct luo_session_header_ser`. This structure
+ *     is the header for a contiguous block of memory containing an array of
+ *     `struct luo_session_ser`, one for each preserved session.
+ *
+ * Serialization Structures:
+ *   The FDT properties point to memory regions containing arrays of simple,
+ *   `__packed` structures. These structures contain the actual preserved state.
+ *
+ *   - struct luo_session_header_ser:
+ *     Header for the session array. Contains the total page count of the
+ *     preserved memory block and the number of `struct luo_session_ser`
+ *     entries that follow.
+ *
+ *   - struct luo_session_ser:
+ *     Metadata for a single session, including its name and a physical pointer
+ *     to another preserved memory block containing an array of
+ *     `struct luo_file_ser` for all files in that session.
+ *
+ *   - struct luo_file_ser:
+ *     Metadata for a single preserved file. Contains the `compatible` string to
+ *     find the correct handler in the new kernel, a user-provided `token` for
+ *     identification, and an opaque `data` handle for the handler to use.
+ */
+
+#ifndef _LINUX_KHO_ABI_LUO_H
+#define _LINUX_KHO_ABI_LUO_H
+
+#include <uapi/linux/liveupdate.h>
+
+/*
+ * The LUO FDT hooks all LUO state for sessions, fds, etc.
+ * In the root it also carries "liveupdate-number" 64-bit property that
+ * corresponds to the number of live-updates performed on this machine.
+ */
+#define LUO_FDT_SIZE		PAGE_SIZE
+#define LUO_FDT_KHO_ENTRY_NAME	"LUO"
+#define LUO_FDT_COMPATIBLE	"luo-v1"
+#define LUO_FDT_LIVEUPDATE_NUM	"liveupdate-number"
+
+#define LIVEUPDATE_HNDL_COMPAT_LENGTH	48
+
+/**
+ * struct luo_file_ser - Represents the serialized preserves files.
+ * @compatible:  File handler compatible string.
+ * @data:        Private data
+ * @token:       User provided token for this file
+ *
+ * If this structure is modified, LUO_SESSION_COMPATIBLE must be updated.
+ */
+struct luo_file_ser {
+	char compatible[LIVEUPDATE_HNDL_COMPAT_LENGTH];
+	u64 data;
+	u64 token;
+} __packed;
+
+/**
+ * struct luo_file_set_ser - Represents the serialized metadata for file set
+ * @files:   The physical address of a contiguous memory block that holds
+ *           the serialized state of files (array of luo_file_ser) in this file
+ *           set.
+ * @count:   The total number of files that were part of this session during
+ *           serialization. Used for iteration and validation during
+ *           restoration.
+ */
+struct luo_file_set_ser {
+	u64 files;
+	u64 count;
+} __packed;
+
+/*
+ * LUO FDT session node
+ * LUO_FDT_SESSION_HEADER:  is a u64 physical address of struct
+ *                          luo_session_header_ser
+ */
+#define LUO_FDT_SESSION_NODE_NAME	"luo-session"
+#define LUO_FDT_SESSION_COMPATIBLE	"luo-session-v2"
+#define LUO_FDT_SESSION_HEADER		"luo-session-header"
+
+/**
+ * struct luo_session_header_ser - Header for the serialized session data block.
+ * @count: The number of `struct luo_session_ser` entries that immediately
+ *         follow this header in the memory block.
+ *
+ * This structure is located at the beginning of a contiguous block of
+ * physical memory preserved across the kexec. It provides the necessary
+ * metadata to interpret the array of session entries that follow.
+ *
+ * If this structure is modified, `LUO_FDT_SESSION_COMPATIBLE` must be updated.
+ */
+struct luo_session_header_ser {
+	u64 count;
+} __packed;
+
+/**
+ * struct luo_session_ser - Represents the serialized metadata for a LUO session.
+ * @name:         The unique name of the session, provided by the userspace at
+ *                the time of session creation.
+ * @file_set_ser: Serialized files belonging to this session,
+ *
+ * This structure is used to package session-specific metadata for transfer
+ * between kernels via Kexec Handover. An array of these structures (one per
+ * session) is created and passed to the new kernel, allowing it to reconstruct
+ * the session context.
+ *
+ * If this structure is modified, `LUO_FDT_SESSION_COMPATIBLE` must be updated.
+ */
+struct luo_session_ser {
+	char name[LIVEUPDATE_SESSION_NAME_LENGTH];
+	struct luo_file_set_ser file_set_ser;
+} __packed;
+
+#endif /* _LINUX_KHO_ABI_LUO_H */
diff --git a/include/linux/kho/abi/memfd.h b/include/linux/kho/abi/memfd.h
new file mode 100644
index 000000000000..da7d063474a1
--- /dev/null
+++ b/include/linux/kho/abi/memfd.h
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Copyright (c) 2025, Google LLC.
+ * Pasha Tatashin <pasha.tatashin@soleen.com>
+ *
+ * Copyright (C) 2025 Amazon.com Inc. or its affiliates.
+ * Pratyush Yadav <ptyadav@amazon.de>
+ */
+
+#ifndef _LINUX_KHO_ABI_MEMFD_H
+#define _LINUX_KHO_ABI_MEMFD_H
+
+#include <linux/types.h>
+#include <linux/kexec_handover.h>
+
+/**
+ * DOC: memfd Live Update ABI
+ *
+ * This header defines the ABI for preserving the state of a memfd across a
+ * kexec reboot using the LUO.
+ *
+ * The state is serialized into a packed structure `struct memfd_luo_ser`
+ * which is handed over to the next kernel via the KHO mechanism.
+ *
+ * This interface is a contract. Any modification to the structure layout
+ * constitutes a breaking change. Such changes require incrementing the
+ * version number in the MEMFD_LUO_FH_COMPATIBLE string.
+ */
+
+/**
+ * MEMFD_LUO_FOLIO_DIRTY - The folio is dirty.
+ *
+ * This flag indicates the folio contains data from user. A non-dirty folio is
+ * one that was allocated (say using fallocate(2)) but not written to.
+ */
+#define MEMFD_LUO_FOLIO_DIRTY		BIT(0)
+
+/**
+ * MEMFD_LUO_FOLIO_UPTODATE - The folio is up-to-date.
+ *
+ * An up-to-date folio has been zeroed out. shmem zeroes out folios on first
+ * use. This flag tracks which folios need zeroing.
+ */
+#define MEMFD_LUO_FOLIO_UPTODATE	BIT(1)
+
+/**
+ * struct memfd_luo_folio_ser - Serialized state of a single folio.
+ * @pfn:       The page frame number of the folio.
+ * @flags:     Flags to describe the state of the folio.
+ * @index:     The page offset (pgoff_t) of the folio within the original file.
+ */
+struct memfd_luo_folio_ser {
+	u64 pfn:52;
+	u64 flags:12;
+	u64 index;
+} __packed;
+
+/**
+ * struct memfd_luo_ser - Main serialization structure for a memfd.
+ * @pos:       The file's current position (f_pos).
+ * @size:      The total size of the file in bytes (i_size).
+ * @nr_folios: Number of folios in the folios array.
+ * @folios:    KHO vmalloc descriptor pointing to the array of
+ *             struct memfd_luo_folio_ser.
+ */
+struct memfd_luo_ser {
+	u64 pos;
+	u64 size;
+	u64 nr_folios;
+	struct kho_vmalloc folios;
+} __packed;
+
+/* The compatibility string for memfd file handler */
+#define MEMFD_LUO_FH_COMPATIBLE	"memfd-v1"
+
+#endif /* _LINUX_KHO_ABI_MEMFD_H */
diff --git a/include/linux/liveupdate.h b/include/linux/liveupdate.h
new file mode 100644
index 000000000000..a7f6ee5b6771
--- /dev/null
+++ b/include/linux/liveupdate.h
@@ -0,0 +1,138 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Copyright (c) 2025, Google LLC.
+ * Pasha Tatashin <pasha.tatashin@soleen.com>
+ */
+#ifndef _LINUX_LIVEUPDATE_H
+#define _LINUX_LIVEUPDATE_H
+
+#include <linux/bug.h>
+#include <linux/compiler.h>
+#include <linux/kho/abi/luo.h>
+#include <linux/list.h>
+#include <linux/types.h>
+#include <uapi/linux/liveupdate.h>
+
+struct liveupdate_file_handler;
+struct file;
+
+/**
+ * struct liveupdate_file_op_args - Arguments for file operation callbacks.
+ * @handler:          The file handler being called.
+ * @retrieved:        The retrieve status for the 'can_finish / finish'
+ *                    operation.
+ * @file:             The file object. For retrieve: [OUT] The callback sets
+ *                    this to the new file. For other ops: [IN] The caller sets
+ *                    this to the file being operated on.
+ * @serialized_data:  The opaque u64 handle, preserve/prepare/freeze may update
+ *                    this field.
+ * @private_data:     Private data for the file used to hold runtime state that
+ *                    is not preserved. Set by the handler's .preserve()
+ *                    callback, and must be freed in the handler's
+ *                    .unpreserve() callback.
+ *
+ * This structure bundles all parameters for the file operation callbacks.
+ * The 'data' and 'file' fields are used for both input and output.
+ */
+struct liveupdate_file_op_args {
+	struct liveupdate_file_handler *handler;
+	bool retrieved;
+	struct file *file;
+	u64 serialized_data;
+	void *private_data;
+};
+
+/**
+ * struct liveupdate_file_ops - Callbacks for live-updatable files.
+ * @can_preserve: Required. Lightweight check to see if this handler is
+ *                compatible with the given file.
+ * @preserve:     Required. Performs state-saving for the file.
+ * @unpreserve:   Required. Cleans up any resources allocated by @preserve.
+ * @freeze:       Optional. Final actions just before kernel transition.
+ * @unfreeze:     Optional. Undo freeze operations.
+ * @retrieve:     Required. Restores the file in the new kernel.
+ * @can_finish:   Optional. Check if this FD can finish, i.e. all restoration
+ *                pre-requirements for this FD are satisfied. Called prior to
+ *                finish, in order to do successful finish calls for all
+ *                resources in the session.
+ * @finish:       Required. Final cleanup in the new kernel.
+ * @owner:        Module reference
+ *
+ * All operations (except can_preserve) receive a pointer to a
+ * 'struct liveupdate_file_op_args' containing the necessary context.
+ */
+struct liveupdate_file_ops {
+	bool (*can_preserve)(struct liveupdate_file_handler *handler,
+			     struct file *file);
+	int (*preserve)(struct liveupdate_file_op_args *args);
+	void (*unpreserve)(struct liveupdate_file_op_args *args);
+	int (*freeze)(struct liveupdate_file_op_args *args);
+	void (*unfreeze)(struct liveupdate_file_op_args *args);
+	int (*retrieve)(struct liveupdate_file_op_args *args);
+	bool (*can_finish)(struct liveupdate_file_op_args *args);
+	void (*finish)(struct liveupdate_file_op_args *args);
+	struct module *owner;
+};
+
+/**
+ * struct liveupdate_file_handler - Represents a handler for a live-updatable file type.
+ * @ops:                Callback functions
+ * @compatible:         The compatibility string (e.g., "memfd-v1", "vfiofd-v1")
+ *                      that uniquely identifies the file type this handler
+ *                      supports. This is matched against the compatible string
+ *                      associated with individual &struct file instances.
+ *
+ * Modules that want to support live update for specific file types should
+ * register an instance of this structure. LUO uses this registration to
+ * determine if a given file can be preserved and to find the appropriate
+ * operations to manage its state across the update.
+ */
+struct liveupdate_file_handler {
+	const struct liveupdate_file_ops *ops;
+	const char compatible[LIVEUPDATE_HNDL_COMPAT_LENGTH];
+
+	/* private: */
+
+	/*
+	 * Used for linking this handler instance into a global list of
+	 * registered file handlers.
+	 */
+	struct list_head __private list;
+};
+
+#ifdef CONFIG_LIVEUPDATE
+
+/* Return true if live update orchestrator is enabled */
+bool liveupdate_enabled(void);
+
+/* Called during kexec to tell LUO that entered into reboot */
+int liveupdate_reboot(void);
+
+int liveupdate_register_file_handler(struct liveupdate_file_handler *fh);
+int liveupdate_unregister_file_handler(struct liveupdate_file_handler *fh);
+
+#else /* CONFIG_LIVEUPDATE */
+
+static inline bool liveupdate_enabled(void)
+{
+	return false;
+}
+
+static inline int liveupdate_reboot(void)
+{
+	return 0;
+}
+
+static inline int liveupdate_register_file_handler(struct liveupdate_file_handler *fh)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int liveupdate_unregister_file_handler(struct liveupdate_file_handler *fh)
+{
+	return -EOPNOTSUPP;
+}
+
+#endif /* CONFIG_LIVEUPDATE */
+#endif /* _LINUX_LIVEUPDATE_H */
diff --git a/include/linux/math.h b/include/linux/math.h
index 0198c92cbe3e..6dc1d1d32fbc 100644
--- a/include/linux/math.h
+++ b/include/linux/math.h
@@ -148,11 +148,16 @@ __STRUCT_FRACT(u32)
 
 /**
  * abs - return absolute value of an argument
- * @x: the value.  If it is unsigned type, it is converted to signed type first.
- *     char is treated as if it was signed (regardless of whether it really is)
- *     but the macro's return type is preserved as char.
+ * @x: the value.
  *
- * Return: an absolute value of x.
+ * If it is unsigned type, @x is converted to signed type first.
+ * char is treated as if it was signed (regardless of whether it really is)
+ * but the macro's return type is preserved as char.
+ *
+ * NOTE, for signed type if @x is the minimum, the returned result is undefined
+ * as there is not enough bits to represent it as a positive number.
+ *
+ * Return: an absolute value of @x.
  */
 #define abs(x)	__abs_choose_expr(x, long long,				\
 		__abs_choose_expr(x, long,				\
diff --git a/include/linux/math64.h b/include/linux/math64.h
index 6aaccc1626ab..cc305206d89f 100644
--- a/include/linux/math64.h
+++ b/include/linux/math64.h
@@ -158,6 +158,17 @@ static inline u64 mul_u32_u32(u32 a, u32 b)
 }
 #endif
 
+#ifndef add_u64_u32
+/*
+ * Many a GCC version also messes this up.
+ * Zero extending b and then spilling everything to stack.
+ */
+static inline u64 add_u64_u32(u64 a, u32 b)
+{
+	return a + b;
+}
+#endif
+
 #if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
 
 #ifndef mul_u64_u32_shr
@@ -282,7 +293,53 @@ static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor)
 }
 #endif /* mul_u64_u32_div */
 
-u64 mul_u64_u64_div_u64(u64 a, u64 mul, u64 div);
+/**
+ * mul_u64_add_u64_div_u64 - unsigned 64bit multiply, add, and divide
+ * @a: first unsigned 64bit multiplicand
+ * @b: second unsigned 64bit multiplicand
+ * @c: unsigned 64bit addend
+ * @d: unsigned 64bit divisor
+ *
+ * Multiply two 64bit values together to generate a 128bit product
+ * add a third value and then divide by a fourth.
+ * The Generic code divides by 0 if @d is zero and returns ~0 on overflow.
+ * Architecture specific code may trap on zero or overflow.
+ *
+ * Return: (@a * @b + @c) / @d
+ */
+u64 mul_u64_add_u64_div_u64(u64 a, u64 b, u64 c, u64 d);
+
+/**
+ * mul_u64_u64_div_u64 - unsigned 64bit multiply and divide
+ * @a: first unsigned 64bit multiplicand
+ * @b: second unsigned 64bit multiplicand
+ * @d: unsigned 64bit divisor
+ *
+ * Multiply two 64bit values together to generate a 128bit product
+ * and then divide by a third value.
+ * The Generic code divides by 0 if @d is zero and returns ~0 on overflow.
+ * Architecture specific code may trap on zero or overflow.
+ *
+ * Return: @a * @b / @d
+ */
+#define mul_u64_u64_div_u64(a, b, d) mul_u64_add_u64_div_u64(a, b, 0, d)
+
+/**
+ * mul_u64_u64_div_u64_roundup - unsigned 64bit multiply and divide rounded up
+ * @a: first unsigned 64bit multiplicand
+ * @b: second unsigned 64bit multiplicand
+ * @d: unsigned 64bit divisor
+ *
+ * Multiply two 64bit values together to generate a 128bit product
+ * and then divide and round up.
+ * The Generic code divides by 0 if @d is zero and returns ~0 on overflow.
+ * Architecture specific code may trap on zero or overflow.
+ *
+ * Return: (@a * @b + @d - 1) / @d
+ */
+#define mul_u64_u64_div_u64_roundup(a, b, d) \
+	({ u64 _tmp = (d); mul_u64_add_u64_div_u64(a, b, _tmp - 1, _tmp); })
+
 
 /**
  * DIV64_U64_ROUND_UP - unsigned 64bit divide with 64bit divisor rounded up
diff --git a/include/linux/once_lite.h b/include/linux/once_lite.h
index 27de7bc32a06..236592c4eeb1 100644
--- a/include/linux/once_lite.h
+++ b/include/linux/once_lite.h
@@ -16,7 +16,7 @@
 		bool __ret_cond = !!(condition);			\
 		bool __ret_once = false;				\
 									\
-		if (unlikely(__ret_cond && !__already_done)) {		\
+		if (unlikely(__ret_cond) && unlikely(!__already_done)) {\
 			__already_done = true;				\
 			__ret_once = true;				\
 		}							\
diff --git a/include/linux/panic.h b/include/linux/panic.h
index 6f972a66c13e..a00bc0937698 100644
--- a/include/linux/panic.h
+++ b/include/linux/panic.h
@@ -86,7 +86,6 @@ static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
 struct taint_flag {
 	char c_true;		/* character printed when tainted */
 	char c_false;		/* character printed when not tainted */
-	bool module;		/* also show as a per-module taint flag */
 	const char *desc;	/* verbose description of the set taint flag */
 };
 
diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index 8d2ba3749866..4091e978aef2 100644
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -43,8 +43,36 @@ extern void rb_erase(struct rb_node *, struct rb_root *);
 /* Find logical next and previous nodes in a tree */
 extern struct rb_node *rb_next(const struct rb_node *);
 extern struct rb_node *rb_prev(const struct rb_node *);
-extern struct rb_node *rb_first(const struct rb_root *);
-extern struct rb_node *rb_last(const struct rb_root *);
+
+/*
+ * This function returns the first node (in sort order) of the tree.
+ */
+static inline struct rb_node *rb_first(const struct rb_root *root)
+{
+	struct rb_node	*n;
+
+	n = root->rb_node;
+	if (!n)
+		return NULL;
+	while (n->rb_left)
+		n = n->rb_left;
+	return n;
+}
+
+/*
+ * This function returns the last node (in sort order) of the tree.
+ */
+static inline struct rb_node *rb_last(const struct rb_root *root)
+{
+	struct rb_node	*n;
+
+	n = root->rb_node;
+	if (!n)
+		return NULL;
+	while (n->rb_right)
+		n = n->rb_right;
+	return n;
+}
 
 /* Postorder iteration - always visit the parent after its children */
 extern struct rb_node *rb_first_postorder(const struct rb_root *);
diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index 5e4b3c1ae5c2..e2069b3179c4 100644
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -10,6 +10,7 @@
 #include <linux/xattr.h>
 #include <linux/fs_parser.h>
 #include <linux/userfaultfd_k.h>
+#include <linux/bits.h>
 
 struct swap_iocb;
 
@@ -19,6 +20,19 @@ struct swap_iocb;
 #define SHMEM_MAXQUOTAS 2
 #endif
 
+/* Suppress pre-accounting of the entire object size. */
+#define SHMEM_F_NORESERVE	BIT(0)
+/* Disallow swapping. */
+#define SHMEM_F_LOCKED		BIT(1)
+/*
+ * Disallow growing, shrinking, or hole punching in the inode. Combined with
+ * folio pinning, makes sure the inode's mapping stays fixed.
+ *
+ * In some ways similar to F_SEAL_GROW | F_SEAL_SHRINK, but can be removed and
+ * isn't directly visible to userspace.
+ */
+#define SHMEM_F_MAPPING_FROZEN	BIT(2)
+
 struct shmem_inode_info {
 	spinlock_t		lock;
 	unsigned int		seals;		/* shmem seals */
@@ -186,6 +200,15 @@ static inline bool shmem_file(struct file *file)
 	return shmem_mapping(file->f_mapping);
 }
 
+/* Must be called with inode lock taken exclusive. */
+static inline void shmem_freeze(struct inode *inode, bool freeze)
+{
+	if (freeze)
+		SHMEM_I(inode)->flags |= SHMEM_F_MAPPING_FROZEN;
+	else
+		SHMEM_I(inode)->flags &= ~SHMEM_F_MAPPING_FROZEN;
+}
+
 /*
  * If fallocate(FALLOC_FL_KEEP_SIZE) has been used, there may be pages
  * beyond i_size's notion of EOF, which fallocate has committed to reserving:
diff --git a/include/linux/sys_info.h b/include/linux/sys_info.h
index 89d77dc4f2ed..a5bc3ea3d44b 100644
--- a/include/linux/sys_info.h
+++ b/include/linux/sys_info.h
@@ -14,7 +14,7 @@
 #define SYS_INFO_LOCKS			0x00000008
 #define SYS_INFO_FTRACE			0x00000010
 #define SYS_INFO_PANIC_CONSOLE_REPLAY	0x00000020
-#define SYS_INFO_ALL_CPU_BT		0x00000040
+#define SYS_INFO_ALL_BT			0x00000040
 #define SYS_INFO_BLOCKED_TASKS		0x00000080
 
 void sys_info(unsigned long si_mask);
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index be395f5f7ee3..1f3804245c06 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -161,8 +161,6 @@ __copy_to_user(void __user *to, const void *from, unsigned long n)
  * directly in the normal copy_to/from_user(), the other ones go
  * through an extern _copy_to/from_user(), which expands the same code
  * here.
- *
- * Rust code always uses the extern definition.
  */
 static inline __must_check unsigned long
 _inline_copy_from_user(void *to, const void __user *from, unsigned long n)
@@ -192,8 +190,10 @@ fail:
 	memset(to + (n - res), 0, res);
 	return res;
 }
+#ifndef INLINE_COPY_FROM_USER
 extern __must_check unsigned long
 _copy_from_user(void *, const void __user *, unsigned long);
+#endif
 
 static inline __must_check unsigned long
 _inline_copy_to_user(void __user *to, const void *from, unsigned long n)
@@ -207,8 +207,10 @@ _inline_copy_to_user(void __user *to, const void *from, unsigned long n)
 	}
 	return n;
 }
+#ifndef INLINE_COPY_TO_USER
 extern __must_check unsigned long
 _copy_to_user(void __user *, const void *, unsigned long);
+#endif
 
 static __always_inline unsigned long __must_check
 copy_from_user(void *to, const void __user *from, unsigned long n)
diff --git a/include/linux/util_macros.h b/include/linux/util_macros.h
index 9373962aade9..2eb528058d0d 100644
--- a/include/linux/util_macros.h
+++ b/include/linux/util_macros.h
@@ -136,10 +136,10 @@
 #define PTR_IF(cond, ptr)	((cond) ? (ptr) : NULL)
 
 /**
- * to_user_ptr - cast a pointer passed as u64 from user space to void __user *
+ * u64_to_user_ptr - cast a pointer passed as u64 from user space to void __user *
  * @x: The u64 value from user space, usually via IOCTL
  *
- * to_user_ptr() simply casts a pointer passed as u64 from user space to void
+ * u64_to_user_ptr() simply casts a pointer passed as u64 from user space to void
  * __user * correctly. Using this lets us get rid of all the tiresome casts.
  */
 #define u64_to_user_ptr(x)		\
diff --git a/include/linux/vmcore_info.h b/include/linux/vmcore_info.h
index 37e003ae5262..e71518caacdf 100644
--- a/include/linux/vmcore_info.h
+++ b/include/linux/vmcore_info.h
@@ -5,6 +5,7 @@
 #include <linux/linkage.h>
 #include <linux/elfcore.h>
 #include <linux/elf.h>
+#include <uapi/linux/vmcore.h>
 
 #define CRASH_CORE_NOTE_HEAD_BYTES ALIGN(sizeof(struct elf_note), 4)
 #define CRASH_CORE_NOTE_NAME_BYTES ALIGN(sizeof(NN_PRSTATUS), 4)
@@ -77,4 +78,11 @@ 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);
+
+#ifdef CONFIG_VMCORE_INFO
+void hwerr_log_error_type(enum hwerr_error_type src);
+#else
+static inline void hwerr_log_error_type(enum hwerr_error_type src) {};
+#endif
+
 #endif /* LINUX_VMCORE_INFO_H */
diff --git a/include/linux/xxhash.h b/include/linux/xxhash.h
index 27f57eca8cb1..587122e2c29c 100644
--- a/include/linux/xxhash.h
+++ b/include/linux/xxhash.h
@@ -141,21 +141,7 @@ static inline unsigned long xxhash(const void *input, size_t length,
  */
 
 /**
- * struct xxh32_state - private xxh32 state, do not use members directly
- */
-struct xxh32_state {
-	uint32_t total_len_32;
-	uint32_t large_len;
-	uint32_t v1;
-	uint32_t v2;
-	uint32_t v3;
-	uint32_t v4;
-	uint32_t mem32[4];
-	uint32_t memsize;
-};
-
-/**
- * struct xxh32_state - private xxh64 state, do not use members directly
+ * struct xxh64_state - private xxh64 state, do not use members directly
  */
 struct xxh64_state {
 	uint64_t total_len;
@@ -168,16 +154,6 @@ struct xxh64_state {
 };
 
 /**
- * xxh32_reset() - reset the xxh32 state to start a new hashing operation
- *
- * @state: The xxh32 state to reset.
- * @seed:  Initialize the hash state with this seed.
- *
- * Call this function on any xxh32_state to prepare for a new hashing operation.
- */
-void xxh32_reset(struct xxh32_state *state, uint32_t seed);
-
-/**
  * xxh64_reset() - reset the xxh64 state to start a new hashing operation
  *
  * @state: The xxh64 state to reset.
@@ -210,24 +186,4 @@ int xxh64_update(struct xxh64_state *state, const void *input, size_t length);
  */
 uint64_t xxh64_digest(const struct xxh64_state *state);
 
-/*-**************************
- * Utils
- ***************************/
-
-/**
- * xxh32_copy_state() - copy the source state into the destination state
- *
- * @src: The source xxh32 state.
- * @dst: The destination xxh32 state.
- */
-void xxh32_copy_state(struct xxh32_state *dst, const struct xxh32_state *src);
-
-/**
- * xxh64_copy_state() - copy the source state into the destination state
- *
- * @src: The source xxh64 state.
- * @dst: The destination xxh64 state.
- */
-void xxh64_copy_state(struct xxh64_state *dst, const struct xxh64_state *src);
-
 #endif /* XXHASH_H */