Merge tag 'io_uring-7.3-20261002' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linuxgrafted

Pull io_uring fixes from Jens Axboe:

 - Fix a task_work add use-after-free with SQPOLL.

   The sqpoll thread could pop and complete the last request while
   io_req_normal_work_add() was still looking at them after the mpscq
   push.

   Use the same approach as DEFER_TASKRUN to protect from that, holding
   an RCU read lock across the add, and have exit wait for an RCU grace
   period for SQPOLL rings as well.

 - CQE32 ring fixes: correct the free entry check for 32b CQEs, zero the
   big_cqe for aux CQEs, and only post the dummy skip CQE on CQE_MIXED
   rings

 - Mark the source filter table as COW when cloning bpf filters, so
   registering another filter on the source doesn't modify the shared
   table in place

 - Initialize the task context before running the BPF loop

 - Requeue zcrx multishot receives stopped by a local resource

 - End a TX_TIMESTAMP multishot cmd when the CQ is full (lollipopkit)

* tag 'io_uring-7.3-20261002' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux:
  io_uring: fix task_work add use-after-free with SQPOLL
  io_uring/cmd_net: end TX_TIMESTAMP multishot when the CQ is full
  io_uring/zcrx: requeue multishot receives stopped by a local resource
  io_uring: initialize task context before running the BPF loop
  io_uring: zero big_cqe for aux CQEs on CQE32 rings
  io_uring: fix free entry check for 32b CQEs on CQE32 rings
  io_uring: only post the dummy skip CQE on CQE_MIXED rings
  io_uring/bpf_filter: mark source as COW when cloning filters

23 files changed, 1188 insertions, 0 deletions

diff --git a/arch/um/include/shared/arch.h b/arch/um/include/shared/arch.h
new file mode 100644
index 000000000..cc398a21a
--- /dev/null
+++ b/arch/um/include/shared/arch.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
+#ifndef __ARCH_H__
+#define __ARCH_H__
+
+#include <sysdep/ptrace.h>
+
+extern void arch_check_bugs(void);
+extern int arch_fixup(unsigned long address, struct uml_pt_regs *regs);
+extern void arch_examine_signal(int sig, struct uml_pt_regs *regs);
+
+void mc_set_rip(void *_mc, void *target);
+
+#endif
diff --git a/arch/um/include/shared/as-layout.h b/arch/um/include/shared/as-layout.h
new file mode 100644
index 000000000..02ef258e3
--- /dev/null
+++ b/arch/um/include/shared/as-layout.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
+#ifndef __START_H__
+#define __START_H__
+
+#include <generated/asm-offsets.h>
+
+/*
+ * Stolen from linux/const.h, which can't be directly included since
+ * this is used in userspace code, which has no access to the kernel
+ * headers.  Changed to be suitable for adding casts to the start,
+ * rather than "UL" to the end.
+ */
+
+/* Some constant macros are used in both assembler and
+ * C code.  Therefore we cannot annotate them always with
+ * 'UL' and other type specifiers unilaterally.  We
+ * use the following macros to deal with this.
+ */
+#define STUB_START stub_start
+#define STUB_CODE STUB_START
+#define STUB_DATA (STUB_CODE + UM_KERN_PAGE_SIZE)
+#define STUB_DATA_PAGES 2
+#define STUB_SIZE ((1 + STUB_DATA_PAGES) * UM_KERN_PAGE_SIZE)
+#define STUB_END (STUB_START + STUB_SIZE)
+
+#ifndef __ASSEMBLER__
+
+#include <sysdep/ptrace.h>
+
+struct task_struct;
+extern struct task_struct *cpu_tasks[];
+
+extern unsigned long long physmem_size;
+
+extern unsigned long high_physmem;
+extern unsigned long uml_physmem;
+extern unsigned long uml_reserved;
+extern unsigned long end_vm;
+extern unsigned long start_vm;
+
+extern unsigned long brk_start;
+
+extern unsigned long stub_start;
+
+extern int linux_main(int argc, char **argv, char **envp);
+extern void uml_finishsetup(void);
+
+struct siginfo;
+extern void (*sig_info[])(int, struct siginfo *si, struct uml_pt_regs *, void *);
+
+#endif
+
+#endif
diff --git a/arch/um/include/shared/elf_user.h b/arch/um/include/shared/elf_user.h
new file mode 100644
index 000000000..fd461ee40
--- /dev/null
+++ b/arch/um/include/shared/elf_user.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2004 Fujitsu Siemens Computers GmbH
+ * Author: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
+ */
+
+#ifndef __ELF_USER_H__
+#define __ELF_USER_H__
+
+/* For compilation on a host that doesn't support AT_SYSINFO (Linux 2.4)  */
+
+#ifndef AT_SYSINFO
+#define AT_SYSINFO 32
+#endif
+#ifndef AT_SYSINFO_EHDR
+#define AT_SYSINFO_EHDR 33
+#endif
+
+#endif
diff --git a/arch/um/include/shared/frame_kern.h b/arch/um/include/shared/frame_kern.h
new file mode 100644
index 000000000..ed952ac66
--- /dev/null
+++ b/arch/um/include/shared/frame_kern.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* 
+ * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ */
+
+#ifndef __FRAME_KERN_H_
+#define __FRAME_KERN_H_
+
+extern int setup_signal_stack_sc(unsigned long stack_top, struct ksignal *ksig,
+				 struct pt_regs *regs, sigset_t *mask);
+extern int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig,
+				 struct pt_regs *regs, sigset_t *mask);
+
+#endif
+
diff --git a/arch/um/include/shared/init.h b/arch/um/include/shared/init.h
new file mode 100644
index 000000000..1a659e2e8
--- /dev/null
+++ b/arch/um/include/shared/init.h
@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_UML_INIT_H
+#define _LINUX_UML_INIT_H
+
+/* These macros are used to mark some functions or
+ * initialized data (doesn't apply to uninitialized data)
+ * as `initialization' functions. The kernel can take this
+ * as hint that the function is used only during the initialization
+ * phase and free up used memory resources after
+ *
+ * Usage:
+ * For functions:
+ *
+ * You should add __init immediately before the function name, like:
+ *
+ * static void __init initme(int x, int y)
+ * {
+ *    extern int z; z = x * y;
+ * }
+ *
+ * If the function has a prototype somewhere, you can also add
+ * __init between closing brace of the prototype and semicolon:
+ *
+ * extern int initialize_foobar_device(int, int, int) __init;
+ *
+ * For initialized data:
+ * You should insert __initdata between the variable name and equal
+ * sign followed by value, e.g.:
+ *
+ * static int init_variable __initdata = 0;
+ * static const char linux_logo[] __initconst = { 0x32, 0x36, ... };
+ *
+ * Don't forget to initialize data not at file scope, i.e. within a function,
+ * as gcc otherwise puts the data into the bss section and not into the init
+ * section.
+ *
+ * Also note, that this data cannot be "const".
+ */
+
+#ifndef _LINUX_INIT_H
+typedef int (*initcall_t)(void);
+typedef void (*exitcall_t)(void);
+
+#include <linux/compiler_types.h>
+
+/* These are for everybody (although not all archs will actually
+   discard it in modules) */
+#define __init		__section(".init.text")
+#define __initdata	__section(".init.data")
+#define __exitdata	__section(".exit.data")
+#define __exit_call	__used __section(".exitcall.exit")
+
+#ifdef MODULE
+#define __exit		__section(".exit.text")
+#else
+#define __exit		__used __section(".exit.text")
+#endif
+
+#endif
+
+#ifndef MODULE
+struct uml_param {
+        const char *str;
+        int (*setup_func)(char *, int *);
+};
+
+extern initcall_t __uml_postsetup_start, __uml_postsetup_end;
+extern const char *__uml_help_start, *__uml_help_end;
+#endif
+
+#define __uml_exitcall(fn)						\
+	static exitcall_t __uml_exitcall_##fn __uml_exit_call = fn
+
+extern struct uml_param __uml_setup_start, __uml_setup_end;
+
+#define __uml_postsetup(fn)						\
+	static initcall_t __uml_postsetup_##fn __uml_postsetup_call = fn
+
+#define __non_empty_string(dummyname,string)				\
+	struct __uml_non_empty_string_struct_##dummyname		\
+	{								\
+		char _string[sizeof(string)-2];				\
+	}
+
+#ifndef MODULE
+#define __uml_setup(str, fn, help...)					\
+	__non_empty_string(fn ##_setup, str);				\
+	__uml_help(fn, help);						\
+	static char __uml_setup_str_##fn[] __initdata = str;		\
+	static struct uml_param __uml_setup_##fn __uml_init_setup = { __uml_setup_str_##fn, fn }
+#else
+#define __uml_setup(str, fn, help...)					\
+
+#endif
+
+#define __uml_help(fn, help...)						\
+	__non_empty_string(fn ##__help, help);				\
+	static char __uml_help_str_##fn[] __initdata = help;		\
+	static const char *__uml_help_##fn __uml_setup_help = __uml_help_str_##fn
+
+/*
+ * Mark functions and data as being only used at initialization
+ * or exit time.
+ */
+#define __uml_init_setup	__used __section(".uml.setup.init")
+#define __uml_setup_help	__used __section(".uml.help.init")
+#define __uml_postsetup_call	__used __section(".uml.postsetup.init")
+#define __uml_exit_call		__used __section(".uml.exitcall.exit")
+
+#ifdef __UM_HOST__
+
+#define __define_initcall(level,fn) \
+	static initcall_t __initcall_##fn __used \
+	__attribute__((__section__(".initcall" level ".init"))) = fn
+
+/* Userspace initcalls shouldn't depend on anything in the kernel, so we'll
+ * make them run first.
+ */
+#define __initcall(fn) __define_initcall("1", fn)
+
+#define __exitcall(fn) static exitcall_t __exitcall_##fn __exit_call = fn
+
+#define __init_call	__used __section(".initcall.init")
+
+#endif
+
+#endif /* _LINUX_UML_INIT_H */
diff --git a/arch/um/include/shared/irq_kern.h b/arch/um/include/shared/irq_kern.h
new file mode 100644
index 000000000..44357fa6e
--- /dev/null
+++ b/arch/um/include/shared/irq_kern.h
@@ -0,0 +1,80 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com)
+ */
+
+#ifndef __IRQ_KERN_H__
+#define __IRQ_KERN_H__
+
+#include <linux/interrupt.h>
+#include <linux/time-internal.h>
+#include <asm/ptrace.h>
+#include "irq_user.h"
+
+#define UM_IRQ_ALLOC	-1
+
+int um_request_irq(int irq, int fd, enum um_irq_type type,
+		   irq_handler_t handler, unsigned long irqflags,
+		   const char *devname, void *dev_id);
+
+#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
+/**
+ * um_request_irq_tt - request an IRQ with timetravel handler
+ *
+ * @irq: the IRQ number, or %UM_IRQ_ALLOC
+ * @fd: The file descriptor to request an IRQ for
+ * @type: read or write
+ * @handler: the (generic style) IRQ handler
+ * @irqflags: Linux IRQ flags
+ * @devname: name for this to show
+ * @dev_id: data pointer to pass to the IRQ handler
+ * @timetravel_handler: the timetravel interrupt handler, invoked with the IRQ
+ *	number, fd, dev_id and time-travel event pointer.
+ *
+ * Returns: The interrupt number assigned or a negative error.
+ *
+ * Note that the timetravel handler is invoked only if the time_travel_mode is
+ * %TT_MODE_EXTERNAL, and then it is invoked even while the system is suspended!
+ * This function must call time_travel_add_irq_event() for the event passed with
+ * an appropriate delay, before sending an ACK on the socket it was invoked for.
+ *
+ * If this was called while the system is suspended, then adding the event will
+ * cause the system to resume.
+ *
+ * Since this function will almost certainly have to handle the FD's condition,
+ * a read will consume the message, and after that it is up to the code using
+ * it to pass such a message to the @handler in whichever way it can.
+ *
+ * If time_travel_mode is not %TT_MODE_EXTERNAL the @timetravel_handler will
+ * not be invoked at all and the @handler must handle the FD becoming
+ * readable (or writable) instead. Use um_irq_timetravel_handler_used() to
+ * distinguish these cases.
+ *
+ * See virtio_uml.c for an example.
+ */
+int um_request_irq_tt(int irq, int fd, enum um_irq_type type,
+		      irq_handler_t handler, unsigned long irqflags,
+		      const char *devname, void *dev_id,
+		      void (*timetravel_handler)(int, int, void *,
+						 struct time_travel_event *));
+#else
+static inline
+int um_request_irq_tt(int irq, int fd, enum um_irq_type type,
+		      irq_handler_t handler, unsigned long irqflags,
+		      const char *devname, void *dev_id,
+		      void (*timetravel_handler)(int, int, void *,
+						 struct time_travel_event *))
+{
+	return um_request_irq(irq, fd, type, handler, irqflags,
+			      devname, dev_id);
+}
+#endif
+
+static inline bool um_irq_timetravel_handler_used(void)
+{
+	return time_travel_mode == TT_MODE_EXTERNAL;
+}
+
+void um_free_irq(int irq, void *dev_id);
+void free_irqs(void);
+#endif
diff --git a/arch/um/include/shared/irq_user.h b/arch/um/include/shared/irq_user.h
new file mode 100644
index 000000000..746abc24a
--- /dev/null
+++ b/arch/um/include/shared/irq_user.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
+#ifndef __IRQ_USER_H__
+#define __IRQ_USER_H__
+
+#include <sysdep/ptrace.h>
+
+enum um_irq_type {
+	IRQ_READ,
+	IRQ_WRITE,
+	NUM_IRQ_TYPES,
+};
+
+struct siginfo;
+extern void sigio_handler(int sig, struct siginfo *unused_si,
+			  struct uml_pt_regs *regs, void *mc);
+extern void sigchld_handler(int sig, struct siginfo *unused_si,
+			   struct uml_pt_regs *regs, void *mc);
+void sigio_run_timetravel_handlers(void);
+extern void free_irq_by_fd(int fd);
+extern void deactivate_fd(int fd, int irqnum);
+extern int deactivate_all_fds(void);
+
+#endif
diff --git a/arch/um/include/shared/kern.h b/arch/um/include/shared/kern.h
new file mode 100644
index 000000000..3a9c75a84
--- /dev/null
+++ b/arch/um/include/shared/kern.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* 
+ * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
+ */
+
+#ifndef __KERN_H__
+#define __KERN_H__
+
+/* These are all user-mode things which are convenient to call directly
+ * from kernel code and for which writing a wrapper is too much of a pain.
+ * The regular include files can't be included because this file is included
+ * only into kernel code, and user-space includes conflict with kernel
+ * includes.
+ */
+
+extern int printf(const char *fmt, ...);
+extern void *sbrk(int increment);
+extern int pause(void);
+extern void exit(int);
+
+#endif
+
diff --git a/arch/um/include/shared/kern_util.h b/arch/um/include/shared/kern_util.h
new file mode 100644
index 000000000..9812efd14
--- /dev/null
+++ b/arch/um/include/shared/kern_util.h
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
+#ifndef __KERN_UTIL_H__
+#define __KERN_UTIL_H__
+
+#include <sysdep/ptrace.h>
+#include <sysdep/faultinfo.h>
+
+struct siginfo;
+
+extern int uml_exitcode;
+
+extern int kmalloc_ok;
+
+extern unsigned long alloc_stack(int order, int atomic);
+extern void free_stack(unsigned long stack, int order);
+
+struct pt_regs;
+extern void do_signal(struct pt_regs *regs);
+extern void interrupt_end(void);
+extern void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs,
+			 void *mc);
+
+extern unsigned long segv(struct faultinfo fi, unsigned long ip,
+			  int is_user, struct uml_pt_regs *regs,
+			  void *mc);
+extern int handle_page_fault(unsigned long address, unsigned long ip,
+			     int is_write, int is_user, int *code_out);
+
+extern unsigned int do_IRQ(int irq, struct uml_pt_regs *regs);
+extern void initial_thread_cb(void (*proc)(void *), void *arg);
+
+extern void timer_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs);
+
+extern void uml_pm_wake(void);
+
+extern int start_uml(void);
+
+extern void uml_cleanup(void);
+extern void do_uml_exitcalls(void);
+
+/*
+ * Are we disallowed to sleep? Used to choose between GFP_KERNEL and
+ * GFP_ATOMIC.
+ */
+extern int __uml_cant_sleep(void);
+extern int get_current_pid(void);
+extern int copy_from_user_proc(void *to, void *from, int size);
+extern char *uml_strdup(const char *string);
+int uml_need_resched(void);
+
+extern unsigned long to_irq_stack(unsigned long *mask_out);
+extern unsigned long from_irq_stack(int nested);
+
+extern int singlestepping(void);
+
+extern void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs,
+			 void *mc);
+extern void winch(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs,
+		  void *mc);
+extern void fatal_sigsegv(void) __attribute__ ((noreturn));
+
+void um_idle_sleep(void);
+
+void kasan_map_memory(void *start, size_t len);
+
+#endif
diff --git a/arch/um/include/shared/longjmp.h b/arch/um/include/shared/longjmp.h
new file mode 100644
index 000000000..c53e43d98
--- /dev/null
+++ b/arch/um/include/shared/longjmp.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UML_LONGJMP_H
+#define __UML_LONGJMP_H
+
+#include <sysdep/archsetjmp.h>
+#include <os.h>
+
+extern int setjmp(jmp_buf);
+extern void longjmp(jmp_buf, int);
+
+#define UML_LONGJMP(buf, val) do { \
+	longjmp(*buf, val);	\
+} while(0)
+
+#define UML_SETJMP(buf) ({				\
+	int n, enable;					\
+	enable = um_get_signals();			\
+	n = setjmp(*buf);				\
+	if(n != 0)					\
+		um_set_signals_trace(enable);		\
+	n; })
+
+#endif
diff --git a/arch/um/include/shared/mem.h b/arch/um/include/shared/mem.h
new file mode 100644
index 000000000..98aacd544
--- /dev/null
+++ b/arch/um/include/shared/mem.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* 
+ * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
+#ifndef __MEM_H__
+#define __MEM_H__
+
+extern int phys_mapping(unsigned long phys, unsigned long long *offset_out);
+
+extern unsigned long uml_physmem;
+static inline unsigned long uml_to_phys(void *virt)
+{
+	return(((unsigned long) virt) - uml_physmem);
+}
+
+static inline void *uml_to_virt(unsigned long phys)
+{
+	return((void *) uml_physmem + phys);
+}
+
+#endif
diff --git a/arch/um/include/shared/mem_user.h b/arch/um/include/shared/mem_user.h
new file mode 100644
index 000000000..8a5b72872
--- /dev/null
+++ b/arch/um/include/shared/mem_user.h
@@ -0,0 +1,42 @@
+/*
+ * arch/um/include/mem_user.h
+ *
+ * BRIEF MODULE DESCRIPTION
+ * user side memory interface for support IO memory inside user mode linux
+ *
+ * Copyright (C) 2001 RidgeRun, Inc.
+ * Author: RidgeRun, Inc.
+ *         Greg Lonnon glonnon@ridgerun.com or info@ridgerun.com
+ *
+ *  This program is free software; you can redistribute  it and/or modify it
+ *  under  the terms of  the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the  License, or (at your
+ *  option) any later version.
+ *
+ *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
+ *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
+ *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
+ *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
+ *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
+ *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *  You should have received a copy of the  GNU General Public License along
+ *  with this program; if not, write  to the Free Software Foundation, Inc.,
+ *  675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef _MEM_USER_H
+#define _MEM_USER_H
+
+#define ROUND_4M(n) ((((unsigned long) (n)) + (1 << 22)) & ~((1 << 22) - 1))
+
+extern void setup_physmem(unsigned long start, unsigned long usable,
+			  unsigned long len);
+extern void map_memory(unsigned long virt, unsigned long phys,
+		       unsigned long len, int r, int w, int x);
+
+#endif
diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h
new file mode 100644
index 000000000..b26e94292
--- /dev/null
+++ b/arch/um/include/shared/os.h
@@ -0,0 +1,359 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk})
+ * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
+ * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
+#ifndef __OS_H__
+#define __OS_H__
+
+#include <irq_user.h>
+#include <longjmp.h>
+#include <mm_id.h>
+/* This is to get size_t */
+#ifndef __UM_HOST__
+#include <linux/types.h>
+#else
+#include <sys/types.h>
+#endif
+
+#define CATCH_EINTR(expr) while ((errno = 0, ((expr) < 0)) && (errno == EINTR))
+
+#define OS_TYPE_FILE 1
+#define OS_TYPE_DIR 2
+#define OS_TYPE_SYMLINK 3
+#define OS_TYPE_CHARDEV 4
+#define OS_TYPE_BLOCKDEV 5
+#define OS_TYPE_FIFO 6
+#define OS_TYPE_SOCK 7
+
+/* os_access() flags */
+#define OS_ACC_F_OK    0       /* Test for existence.  */
+#define OS_ACC_X_OK    1       /* Test for execute permission.  */
+#define OS_ACC_W_OK    2       /* Test for write permission.  */
+#define OS_ACC_R_OK    4       /* Test for read permission.  */
+#define OS_ACC_RW_OK   (OS_ACC_W_OK | OS_ACC_R_OK) /* Test for RW permission */
+
+#ifdef CONFIG_64BIT
+#define OS_LIB_PATH	"/usr/lib64/"
+#else
+#define OS_LIB_PATH	"/usr/lib/"
+#endif
+
+#define OS_SENDMSG_MAX_FDS 8
+
+/*
+ * types taken from stat_file() in hostfs_user.c
+ * (if they are wrong here, they are wrong there...).
+ */
+struct uml_stat {
+	int                ust_dev;        /* device */
+	unsigned long long ust_ino;        /* inode */
+	int                ust_mode;       /* protection */
+	int                ust_nlink;      /* number of hard links */
+	int                ust_uid;        /* user ID of owner */
+	int                ust_gid;        /* group ID of owner */
+	unsigned long long ust_size;       /* total size, in bytes */
+	int                ust_blksize;    /* blocksize for filesystem I/O */
+	unsigned long long ust_blocks;     /* number of blocks allocated */
+	unsigned long      ust_atime;      /* time of last access */
+	unsigned long      ust_mtime;      /* time of last modification */
+	unsigned long      ust_ctime;      /* time of last change */
+};
+
+struct openflags {
+	unsigned int r : 1;
+	unsigned int w : 1;
+	unsigned int s : 1;	/* O_SYNC */
+	unsigned int c : 1;	/* O_CREAT */
+	unsigned int t : 1;	/* O_TRUNC */
+	unsigned int a : 1;	/* O_APPEND */
+	unsigned int e : 1;	/* O_EXCL */
+	unsigned int cl : 1;    /* FD_CLOEXEC */
+};
+
+#define OPENFLAGS() ((struct openflags) { .r = 0, .w = 0, .s = 0, .c = 0, \
+					  .t = 0, .a = 0, .e = 0, .cl = 0 })
+
+static inline struct openflags of_read(struct openflags flags)
+{
+	flags.r = 1;
+	return flags;
+}
+
+static inline struct openflags of_write(struct openflags flags)
+{
+	flags.w = 1;
+	return flags;
+}
+
+static inline struct openflags of_rdwr(struct openflags flags)
+{
+	return of_read(of_write(flags));
+}
+
+static inline struct openflags of_set_rw(struct openflags flags, int r, int w)
+{
+	flags.r = r;
+	flags.w = w;
+	return flags;
+}
+
+static inline struct openflags of_sync(struct openflags flags)
+{
+	flags.s = 1;
+	return flags;
+}
+
+static inline struct openflags of_create(struct openflags flags)
+{
+	flags.c = 1;
+	return flags;
+}
+
+static inline struct openflags of_trunc(struct openflags flags)
+{
+	flags.t = 1;
+	return flags;
+}
+
+static inline struct openflags of_append(struct openflags flags)
+{
+	flags.a = 1;
+	return flags;
+}
+
+static inline struct openflags of_excl(struct openflags flags)
+{
+	flags.e = 1;
+	return flags;
+}
+
+static inline struct openflags of_cloexec(struct openflags flags)
+{
+	flags.cl = 1;
+	return flags;
+}
+
+/* file.c */
+extern int os_stat_file(const char *file_name, struct uml_stat *buf);
+extern int os_stat_fd(const int fd, struct uml_stat *buf);
+extern int os_access(const char *file, int mode);
+extern int os_set_exec_close(int fd);
+extern int os_ioctl_generic(int fd, unsigned int cmd, unsigned long arg);
+extern int os_get_ifname(int fd, char *namebuf);
+extern int os_mode_fd(int fd, int mode);
+
+extern int os_seek_file(int fd, unsigned long long offset);
+extern int os_open_file(const char *file, struct openflags flags, int mode);
+extern int os_read_file(int fd, void *buf, int len);
+extern int os_write_file(int fd, const void *buf, int count);
+extern int os_sync_file(int fd);
+extern int os_file_size(const char *file, unsigned long long *size_out);
+extern int os_pread_file(int fd, void *buf, int len, unsigned long long offset);
+extern int os_pwrite_file(int fd, const void *buf, int count, unsigned long long offset);
+extern int os_file_modtime(const char *file, long long *modtime);
+extern int os_pipe(int *fd, int stream, int close_on_exec);
+extern int os_set_fd_async(int fd);
+extern int os_clear_fd_async(int fd);
+extern int os_set_fd_block(int fd, int blocking);
+extern int os_accept_connection(int fd);
+extern int os_create_unix_socket(const char *file, int len, int close_on_exec);
+extern int os_shutdown_socket(int fd, int r, int w);
+extern int os_dup_file(int fd);
+extern void os_close_file(int fd);
+ssize_t os_rcv_fd_msg(int fd, int *fds, unsigned int n_fds,
+		      void *data, size_t data_len);
+extern int os_connect_socket(const char *name);
+extern int os_file_type(char *file);
+extern int os_file_mode(const char *file, struct openflags *mode_out);
+extern int os_lock_file(int fd, int excl);
+extern void os_flush_stdout(void);
+extern unsigned os_major(unsigned long long dev);
+extern unsigned os_minor(unsigned long long dev);
+extern unsigned long long os_makedev(unsigned major, unsigned minor);
+extern int os_falloc_punch(int fd, unsigned long long offset, int count);
+extern int os_falloc_zeroes(int fd, unsigned long long offset, int count);
+extern int os_eventfd(unsigned int initval, int flags);
+extern int os_sendmsg_fds(int fd, const void *buf, unsigned int len,
+			  const int *fds, unsigned int fds_num);
+int os_poll(unsigned int n, const int *fds);
+void *os_mmap_rw_shared(int fd, size_t size);
+void *os_mremap_rw_shared(void *old_addr, size_t old_size, size_t new_size);
+
+/* start_up.c */
+extern void os_early_checks(void);
+extern void os_check_bugs(void);
+extern void check_host_supports_tls(int *supports_tls, int *tls_min);
+extern void get_host_cpu_features(
+	void (*flags_helper_func)(char *line),
+	void (*cache_helper_func)(char *line));
+
+/* mem.c */
+extern int create_mem_file(unsigned long long len);
+
+/* tlb.c */
+extern void report_enomem(void);
+
+/* process.c */
+pid_t os_reap_child(void);
+extern void os_alarm_process(int pid);
+extern void os_kill_process(int pid, int reap_child);
+extern void os_kill_ptraced_process(int pid, int reap_child);
+
+extern int os_getpid(void);
+
+extern void init_new_thread_signals(void);
+
+extern int os_map_memory(void *virt, int fd, unsigned long long off,
+			 unsigned long len, int r, int w, int x);
+extern int os_protect_memory(void *addr, unsigned long len,
+			     int r, int w, int x);
+extern int os_unmap_memory(void *addr, int len);
+extern int os_drop_memory(void *addr, int length);
+extern int can_drop_memory(void);
+
+void os_set_pdeathsig(void);
+
+int os_futex_wait(void *uaddr, unsigned int val);
+int os_futex_wake(void *uaddr);
+
+/* execvp.c */
+extern int execvp_noalloc(char *buf, const char *file, char *const argv[]);
+/* helper.c */
+extern int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv);
+extern int run_helper_thread(int (*proc)(void *), void *arg,
+			     unsigned int flags, unsigned long *stack_out);
+extern int helper_wait(int pid);
+
+struct os_helper_thread;
+int os_run_helper_thread(struct os_helper_thread **td_out,
+			 void *(*routine)(void *), void *arg);
+void os_kill_helper_thread(struct os_helper_thread *td);
+void os_fix_helper_thread_signals(void);
+
+/* umid.c */
+extern int umid_file_name(char *name, char *buf, int len);
+extern int set_umid(char *name);
+extern char *get_umid(void);
+
+/* signal.c */
+extern void timer_set_signal_handler(void);
+extern void set_sigstack(void *sig_stack, int size);
+extern void set_handler(int sig);
+extern void send_sigio_to_self(void);
+extern int change_sig(int signal, int on);
+extern void block_signals(void);
+extern void unblock_signals(void);
+extern int um_get_signals(void);
+extern int um_set_signals(int enable);
+extern int um_set_signals_trace(int enable);
+extern void deliver_alarm(void);
+extern void register_pm_wake_signal(void);
+extern void block_signals_hard(void);
+extern void unblock_signals_hard(void);
+extern void mark_sigio_pending(void);
+
+/* util.c */
+extern void stack_protections(unsigned long address);
+extern int raw(int fd);
+extern void setup_machinename(char *machine_out);
+extern void setup_hostinfo(char *buf, int len);
+extern ssize_t os_getrandom(void *buf, size_t len, unsigned int flags);
+extern void os_dump_core(void) __attribute__ ((noreturn));
+extern void um_early_printk(const char *s, unsigned int n);
+extern void os_fix_helper_signals(void);
+extern void os_info(const char *fmt, ...)
+	__attribute__ ((format (printf, 1, 2)));
+extern void os_warn(const char *fmt, ...)
+	__attribute__ ((format (printf, 1, 2)));
+
+/* time.c */
+void os_idle_prepare(void);
+extern void os_idle_sleep(void);
+extern int os_timer_create(void);
+extern int os_timer_set_interval(int cpu, unsigned long long nsecs);
+extern int os_timer_one_shot(int cpu, unsigned long long nsecs);
+extern void os_timer_disable(int cpu);
+extern long long os_persistent_clock_emulation(void);
+extern long long os_nsecs(void);
+
+/* skas/mem.c */
+int syscall_stub_flush(struct mm_id *mm_idp);
+struct stub_syscall *syscall_stub_alloc(struct mm_id *mm_idp);
+void syscall_stub_dump_error(struct mm_id *mm_idp);
+
+int map(struct mm_id *mm_idp, unsigned long virt,
+	unsigned long len, int prot, int phys_fd,
+	unsigned long long offset);
+int unmap(struct mm_id *mm_idp, unsigned long addr, unsigned long len);
+
+/* skas/process.c */
+extern int is_skas_winch(int pid, int fd, void *data);
+extern int start_userspace(struct mm_id *mm_id);
+extern void userspace(struct uml_pt_regs *regs);
+extern void new_thread(void *stack, jmp_buf *buf, void (*handler)(void));
+extern void switch_threads(jmp_buf *me, jmp_buf *you);
+extern int start_idle_thread(void *stack, jmp_buf *switch_buf);
+extern void initial_thread_cb_skas(void (*proc)(void *),
+				 void *arg);
+extern void halt_skas(void);
+extern void reboot_skas(void);
+
+/* irq.c */
+extern int os_waiting_for_events_epoll(void);
+extern void *os_epoll_get_data_pointer(int index);
+extern int os_epoll_triggered(int index, int events);
+extern int os_event_mask(enum um_irq_type irq_type);
+extern int os_setup_epoll(void);
+extern int os_add_epoll_fd(int events, int fd, void *data);
+extern int os_mod_epoll_fd(int events, int fd, void *data);
+extern int os_del_epoll_fd(int fd);
+extern void os_set_ioignore(void);
+extern void os_close_epoll_fd(void);
+extern void um_irqs_suspend(void);
+extern void um_irqs_resume(void);
+
+/* sigio.c */
+extern int add_sigio_fd(int fd);
+extern int ignore_sigio_fd(int fd);
+extern void maybe_sigio_broken(int fd);
+extern void sigio_broken(void);
+/*
+ * unlocked versions for IRQ controller code.
+ *
+ * This is safe because it's used at suspend/resume and nothing
+ * else is running.
+ */
+extern int __add_sigio_fd(int fd);
+extern int __ignore_sigio_fd(int fd);
+
+/* tty.c */
+extern int get_pty(void);
+
+long syscall(long number, ...);
+
+/* irqflags tracing */
+extern void block_signals_trace(void);
+extern void unblock_signals_trace(void);
+extern void um_trace_signals_on(void);
+extern void um_trace_signals_off(void);
+
+/* time-travel */
+extern void deliver_time_travel_irqs(void);
+
+/* smp.c */
+#if IS_ENABLED(CONFIG_SMP)
+void os_init_smp(void);
+int os_start_cpu_thread(int cpu);
+void os_start_secondary(void *arg, jmp_buf *switch_buf);
+int os_send_ipi(int cpu, int vector);
+void os_local_ipi_enable(void);
+void os_local_ipi_disable(void);
+#else /* !CONFIG_SMP */
+static inline void os_local_ipi_enable(void) { }
+static inline void os_local_ipi_disable(void) { }
+#endif /* CONFIG_SMP */
+
+#endif
diff --git a/arch/um/include/shared/ptrace_user.h b/arch/um/include/shared/ptrace_user.h
new file mode 100644
index 000000000..8a705d8f9
--- /dev/null
+++ b/arch/um/include/shared/ptrace_user.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* 
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
+#ifndef __PTRACE_USER_H__
+#define __PTRACE_USER_H__
+
+#include <sys/ptrace.h>
+#include <sysdep/ptrace_user.h>
+
+extern int ptrace_getregs(long pid, unsigned long *regs_out);
+extern int ptrace_setregs(long pid, unsigned long *regs_in);
+
+#endif
diff --git a/arch/um/include/shared/registers.h b/arch/um/include/shared/registers.h
new file mode 100644
index 000000000..7d81b2339
--- /dev/null
+++ b/arch/um/include/shared/registers.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2004 PathScale, Inc
+ */
+
+#ifndef __REGISTERS_H
+#define __REGISTERS_H
+
+#include <sysdep/ptrace.h>
+
+extern int init_pid_registers(int pid);
+extern void get_safe_registers(unsigned long *regs, unsigned long *fp_regs);
+extern int get_fp_registers(int pid, unsigned long *regs);
+extern int put_fp_registers(int pid, unsigned long *regs);
+
+#endif
diff --git a/arch/um/include/shared/sigio.h b/arch/um/include/shared/sigio.h
new file mode 100644
index 000000000..c6c2edce1
--- /dev/null
+++ b/arch/um/include/shared/sigio.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* 
+ * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ */
+
+#ifndef __SIGIO_H__
+#define __SIGIO_H__
+
+extern void sigio_lock(void);
+extern void sigio_unlock(void);
+
+#endif
diff --git a/arch/um/include/shared/skas/mm_id.h b/arch/um/include/shared/skas/mm_id.h
new file mode 100644
index 000000000..18c062143
--- /dev/null
+++ b/arch/um/include/shared/skas/mm_id.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2005 Jeff Dike (jdike@karaya.com)
+ */
+
+#ifndef __MM_ID_H
+#define __MM_ID_H
+
+#include <linux/compiler_types.h>
+
+#define STUB_MAX_FDS 4
+
+struct mm_id {
+	int pid;
+	unsigned long stack;
+	int syscall_data_len;
+
+	/* Only used with SECCOMP mode */
+	int sock;
+	int syscall_fd_num;
+	int syscall_fd_map[STUB_MAX_FDS];
+};
+
+struct mutex *__get_turnstile(struct mm_id *mm_id);
+void enter_turnstile(struct mm_id *mm_id) __acquires(__get_turnstile(mm_id));
+void exit_turnstile(struct mm_id *mm_id) __releases(__get_turnstile(mm_id));
+
+void notify_mm_kill(int pid);
+
+#endif
diff --git a/arch/um/include/shared/skas/skas.h b/arch/um/include/shared/skas/skas.h
new file mode 100644
index 000000000..2237ffede
--- /dev/null
+++ b/arch/um/include/shared/skas/skas.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
+#ifndef __SKAS_H
+#define __SKAS_H
+
+#include <sysdep/ptrace.h>
+
+extern int using_seccomp;
+
+extern void new_thread_handler(void);
+extern void handle_syscall(struct uml_pt_regs *regs);
+extern unsigned long current_stub_stack(void);
+extern struct mm_id *current_mm_id(void);
+extern void current_mm_sync(void);
+void initial_jmpbuf_lock(void);
+void initial_jmpbuf_unlock(void);
+
+#endif
diff --git a/arch/um/include/shared/skas/stub-data.h b/arch/um/include/shared/skas/stub-data.h
new file mode 100644
index 000000000..27db38e95
--- /dev/null
+++ b/arch/um/include/shared/skas/stub-data.h
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+
+ * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
+ * Copyright (C) 2005 Jeff Dike (jdike@karaya.com)
+ */
+
+#ifndef __STUB_DATA_H
+#define __STUB_DATA_H
+
+#include <linux/compiler_types.h>
+#include <as-layout.h>
+#include <sysdep/tls.h>
+#include <sysdep/stub-data.h>
+#include <mm_id.h>
+
+#define FUTEX_IN_CHILD 0
+#define FUTEX_IN_KERN 1
+
+struct stub_init_data {
+	int seccomp;
+
+	unsigned long stub_start;
+
+	int stub_code_fd;
+	unsigned long stub_code_offset;
+	int stub_data_fd;
+	unsigned long stub_data_offset;
+
+	unsigned long signal_handler;
+	unsigned long signal_restorer;
+};
+
+#define STUB_NEXT_SYSCALL(s) \
+	((struct stub_syscall *) (((unsigned long) s) + (s)->cmd_len))
+
+enum stub_syscall_type {
+	STUB_SYSCALL_UNSET = 0,
+	STUB_SYSCALL_MMAP,
+	STUB_SYSCALL_MUNMAP,
+};
+
+struct stub_syscall {
+	struct {
+		unsigned long addr;
+		unsigned long length;
+		unsigned long offset;
+		int fd;
+		int prot;
+	} mem;
+
+	enum stub_syscall_type syscall;
+};
+
+struct stub_data {
+	long err;
+
+	int syscall_data_len;
+	/* 128 leaves enough room for additional fields in the struct */
+	struct stub_syscall syscall_data[(UM_KERN_PAGE_SIZE - 128) / sizeof(struct stub_syscall)] __aligned(16);
+
+	/* data shared with signal handler (only used in seccomp mode) */
+	short restart_wait;
+	unsigned int futex;
+	int signal;
+	unsigned short si_offset;
+	unsigned short mctx_offset;
+
+	/* seccomp architecture specific state restore */
+	struct stub_data_arch arch_data;
+
+	/* Stack for our signal handlers and for calling into . */
+	unsigned char sigstack[UM_KERN_PAGE_SIZE] __aligned(UM_KERN_PAGE_SIZE);
+};
+
+#endif
diff --git a/arch/um/include/shared/smp.h b/arch/um/include/shared/smp.h
new file mode 100644
index 000000000..06e3faa95
--- /dev/null
+++ b/arch/um/include/shared/smp.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UM_SHARED_SMP_H
+#define __UM_SHARED_SMP_H
+
+#if IS_ENABLED(CONFIG_SMP)
+
+extern int uml_ncpus;
+
+int uml_curr_cpu(void);
+void uml_start_secondary(void *opaque);
+void uml_ipi_handler(int vector);
+
+#else /* !CONFIG_SMP */
+
+#define uml_ncpus 1
+#define uml_curr_cpu() 0
+
+#endif /* CONFIG_SMP */
+
+#endif /* __UM_SHARED_SMP_H */
diff --git a/arch/um/include/shared/timetravel.h b/arch/um/include/shared/timetravel.h
new file mode 100644
index 000000000..7c2b277b7
--- /dev/null
+++ b/arch/um/include/shared/timetravel.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019-2021 Intel Corporation
+ */
+#ifndef _UM_TIME_TRAVEL_H_
+#define _UM_TIME_TRAVEL_H_
+
+enum time_travel_mode {
+	TT_MODE_OFF,
+	TT_MODE_BASIC,
+	TT_MODE_INFCPU,
+	TT_MODE_EXTERNAL,
+};
+
+#if IS_ENABLED(CONFIG_UML_TIME_TRAVEL_SUPPORT)
+extern enum time_travel_mode time_travel_mode;
+extern int time_travel_should_print_bc_msg;
+#else
+#define time_travel_mode TT_MODE_OFF
+#define time_travel_should_print_bc_msg 0
+#endif /* CONFIG_UML_TIME_TRAVEL_SUPPORT */
+
+void _time_travel_print_bc_msg(void);
+static inline void time_travel_print_bc_msg(void)
+{
+	if (time_travel_should_print_bc_msg)
+		_time_travel_print_bc_msg();
+}
+
+#endif /* _UM_TIME_TRAVEL_H_ */
diff --git a/arch/um/include/shared/um_malloc.h b/arch/um/include/shared/um_malloc.h
new file mode 100644
index 000000000..815dd03e8
--- /dev/null
+++ b/arch/um/include/shared/um_malloc.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2005 Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
+ */
+
+#ifndef __UM_MALLOC_H__
+#define __UM_MALLOC_H__
+
+#include <generated/asm-offsets.h>
+
+extern void *uml_kmalloc(int size, int flags);
+extern void kfree(const void *ptr);
+
+extern void *vmalloc_noprof(unsigned long size);
+#define vmalloc(...)		vmalloc_noprof(__VA_ARGS__)
+extern void vfree(const void *ptr);
+
+#endif /* __UM_MALLOC_H__ */
+
+
diff --git a/arch/um/include/shared/user.h b/arch/um/include/shared/user.h
new file mode 100644
index 000000000..139eb78a4
--- /dev/null
+++ b/arch/um/include/shared/user.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* 
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
+#ifndef __USER_H__
+#define __USER_H__
+
+#include <generated/asm-offsets.h>
+
+/*
+ * The usual definition - copied here because the kernel provides its own,
+ * fancier, type-safe, definition.  Using that one would require
+ * copying too much infrastructure for my taste, so userspace files
+ * get less checking than kernel files.
+ */
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
+/* This is to get size_t and NULL */
+#ifndef __UM_HOST__
+#include <linux/types.h>
+#else
+#include <stddef.h>
+#include <sys/types.h>
+#endif
+
+extern void panic(const char *fmt, ...)
+	__attribute__ ((format (printf, 1, 2)));
+
+/* Requires preincluding include/linux/kern_levels.h */
+#define UM_KERN_EMERG	KERN_EMERG
+#define UM_KERN_ALERT	KERN_ALERT
+#define UM_KERN_CRIT	KERN_CRIT
+#define UM_KERN_ERR	KERN_ERR
+#define UM_KERN_WARNING	KERN_WARNING
+#define UM_KERN_NOTICE	KERN_NOTICE
+#define UM_KERN_INFO	KERN_INFO
+#define UM_KERN_DEBUG	KERN_DEBUG
+#define UM_KERN_CONT	KERN_CONT
+
+#if IS_ENABLED(CONFIG_PRINTK)
+#define printk(...) _printk(__VA_ARGS__)
+extern int _printk(const char *fmt, ...)
+	__attribute__ ((format (printf, 1, 2)));
+extern void print_hex_dump(const char *level, const char *prefix_str,
+			   int prefix_type, int rowsize, int groupsize,
+			   const void *buf, size_t len, _Bool ascii);
+#else
+static inline int printk(const char *fmt, ...)
+{
+	return 0;
+}
+static inline void print_hex_dump(const char *level, const char *prefix_str,
+				  int prefix_type, int rowsize, int groupsize,
+				  const void *buf, size_t len, _Bool ascii)
+{
+}
+#endif
+
+extern int in_aton(char *str);
+extern size_t strlcat(char *, const char *, size_t);
+extern size_t sized_strscpy(char *, const char *, size_t);
+#define strscpy(dst, src)	sized_strscpy(dst, src, sizeof(dst))
+
+/* Copied from linux/compiler-gcc.h since we can't include it directly */
+#define barrier() __asm__ __volatile__("": : :"memory")
+
+#endif