Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h
index 048ae37..506bcd1 100644
--- a/arch/um/include/shared/os.h
+++ b/arch/um/include/shared/os.h
@@ -1,8 +1,8 @@
+/* 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)
- * Licensed under the GPL
  */
 
 #ifndef __OS_H__
@@ -36,6 +36,8 @@
 #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...).
@@ -175,6 +177,10 @@
 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_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);
 
 /* start_up.c */
 extern void os_early_checks(void);
@@ -231,6 +237,7 @@
 extern void unblock_signals(void);
 extern int get_signals(void);
 extern int set_signals(int enable);
+extern int set_signals_trace(int enable);
 extern int os_is_signal_stack(void);
 extern void deliver_alarm(void);
 
@@ -249,15 +256,13 @@
 
 /* time.c */
 extern void os_idle_sleep(unsigned long long nsecs);
-extern int os_timer_create(void* timer);
-extern int os_timer_set_interval(void* timer, void* its);
-extern int os_timer_one_shot(int ticks);
-extern long long os_timer_disable(void);
-extern long os_timer_remain(void* timer);
+extern int os_timer_create(void);
+extern int os_timer_set_interval(unsigned long long nsecs);
+extern int os_timer_one_shot(unsigned long long nsecs);
+extern void os_timer_disable(void);
 extern void uml_idle_timer(void);
 extern long long os_persistent_clock_emulation(void);
 extern long long os_nsecs(void);
-extern long long os_vnsecs(void);
 
 /* skas/mem.c */
 extern long run_syscall_stub(struct mm_id * mm_idp,
@@ -318,4 +323,10 @@
 
 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);
+
 #endif