diff --git a/arch/um/Kbuild b/arch/um/Kbuild
index a4e40e534e6a..6cf0c1e5927b 100644
--- a/arch/um/Kbuild
+++ b/arch/um/Kbuild
@@ -1 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0-only
+
+obj-y += kernel/ drivers/ os-Linux/
diff --git a/arch/um/Makefile b/arch/um/Makefile
index da4d5256af2f..82f05f250634 100644
--- a/arch/um/Makefile
+++ b/arch/um/Makefile
@@ -18,15 +18,10 @@ else
 endif
 
 ARCH_DIR := arch/um
-OS := $(shell uname -s)
 # We require bash because the vmlinux link and loader script cpp use bash
 # features.
 SHELL := /bin/bash
 
-core-y			+= $(ARCH_DIR)/kernel/		\
-			   $(ARCH_DIR)/drivers/		\
-			   $(ARCH_DIR)/os-$(OS)/
-
 MODE_INCLUDE	+= -I$(srctree)/$(ARCH_DIR)/include/shared/skas
 
 HEADER_ARCH 	:= $(SUBARCH)
@@ -78,7 +73,7 @@ USER_CFLAGS = $(patsubst $(KERNEL_DEFINES),,$(patsubst -I%,,$(KBUILD_CFLAGS))) \
 		-idirafter $(objtree)/include -D__KERNEL__ -D__UM_HOST__
 
 #This will adjust *FLAGS accordingly to the platform.
-include $(srctree)/$(ARCH_DIR)/Makefile-os-$(OS)
+include $(srctree)/$(ARCH_DIR)/Makefile-os-Linux
 
 KBUILD_CPPFLAGS += -I$(srctree)/$(HOST_DIR)/include \
 		   -I$(srctree)/$(HOST_DIR)/include/uapi \
@@ -155,4 +150,4 @@ archclean:
 	@find . \( -name '*.bb' -o -name '*.bbg' -o -name '*.da' \
 		-o -name '*.gcov' \) -type f -print | xargs rm -f
 
-export HEADER_ARCH SUBARCH USER_CFLAGS CFLAGS_NO_HARDENING OS DEV_NULL_PATH
+export HEADER_ARCH SUBARCH USER_CFLAGS CFLAGS_NO_HARDENING DEV_NULL_PATH
diff --git a/arch/um/configs/i386_defconfig b/arch/um/configs/i386_defconfig
index 630be793759e..e543cbac8792 100644
--- a/arch/um/configs/i386_defconfig
+++ b/arch/um/configs/i386_defconfig
@@ -34,6 +34,7 @@ CONFIG_TTY_CHAN=y
 CONFIG_XTERM_CHAN=y
 CONFIG_CON_CHAN="pts"
 CONFIG_SSL_CHAN="pts"
+CONFIG_SOUND=m
 CONFIG_UML_SOUND=m
 CONFIG_DEVTMPFS=y
 CONFIG_DEVTMPFS_MOUNT=y
diff --git a/arch/um/configs/x86_64_defconfig b/arch/um/configs/x86_64_defconfig
index 8540d3370272..939cb12318ca 100644
--- a/arch/um/configs/x86_64_defconfig
+++ b/arch/um/configs/x86_64_defconfig
@@ -32,6 +32,7 @@ CONFIG_TTY_CHAN=y
 CONFIG_XTERM_CHAN=y
 CONFIG_CON_CHAN="pts"
 CONFIG_SSL_CHAN="pts"
+CONFIG_SOUND=m
 CONFIG_UML_SOUND=m
 CONFIG_DEVTMPFS=y
 CONFIG_DEVTMPFS_MOUNT=y
diff --git a/arch/um/drivers/Kconfig b/arch/um/drivers/Kconfig
index 36911b1fddcf..b94b2618e7d8 100644
--- a/arch/um/drivers/Kconfig
+++ b/arch/um/drivers/Kconfig
@@ -111,24 +111,14 @@ config SSL_CHAN
 
 config UML_SOUND
 	tristate "Sound support"
+	depends on SOUND
+	select SOUND_OSS_CORE
 	help
 	  This option enables UML sound support.  If enabled, it will pull in
-	  soundcore and the UML hostaudio relay, which acts as a intermediary
+	  the UML hostaudio relay, which acts as a intermediary
 	  between the host's dsp and mixer devices and the UML sound system.
 	  It is safe to say 'Y' here.
 
-config SOUND
-	tristate
-	default UML_SOUND
-
-config SOUND_OSS_CORE
-	bool
-	default UML_SOUND
-
-config HOSTAUDIO
-	tristate
-	default UML_SOUND
-
 endmenu
 
 menu "UML Network Devices"
diff --git a/arch/um/drivers/Makefile b/arch/um/drivers/Makefile
index a461a950f051..0e6af81096fd 100644
--- a/arch/um/drivers/Makefile
+++ b/arch/um/drivers/Makefile
@@ -54,7 +54,7 @@ obj-$(CONFIG_UML_NET) += net.o
 obj-$(CONFIG_MCONSOLE) += mconsole.o
 obj-$(CONFIG_MMAPPER) += mmapper_kern.o 
 obj-$(CONFIG_BLK_DEV_UBD) += ubd.o 
-obj-$(CONFIG_HOSTAUDIO) += hostaudio.o
+obj-$(CONFIG_UML_SOUND) += hostaudio.o
 obj-$(CONFIG_NULL_CHAN) += null.o 
 obj-$(CONFIG_PORT_CHAN) += port.o
 obj-$(CONFIG_PTY_CHAN) += pty.o
diff --git a/arch/um/drivers/hostaudio_kern.c b/arch/um/drivers/hostaudio_kern.c
index 5b064d360cb7..c42b793bce65 100644
--- a/arch/um/drivers/hostaudio_kern.c
+++ b/arch/um/drivers/hostaudio_kern.c
@@ -310,7 +310,7 @@ static const struct file_operations hostmixer_fops = {
 	.release        = hostmixer_release,
 };
 
-struct {
+static struct {
 	int dev_audio;
 	int dev_mixer;
 } module_data;
diff --git a/arch/um/drivers/port_kern.c b/arch/um/drivers/port_kern.c
index efa8b7304090..c52b3ff3c092 100644
--- a/arch/um/drivers/port_kern.c
+++ b/arch/um/drivers/port_kern.c
@@ -144,7 +144,7 @@ static void port_work_proc(struct work_struct *unused)
 	local_irq_restore(flags);
 }
 
-DECLARE_WORK(port_work, port_work_proc);
+static DECLARE_WORK(port_work, port_work_proc);
 
 static irqreturn_t port_interrupt(int irq, void *data)
 {
diff --git a/arch/um/drivers/slirp_kern.c b/arch/um/drivers/slirp_kern.c
index 2d9769237f08..0a6151ee9572 100644
--- a/arch/um/drivers/slirp_kern.c
+++ b/arch/um/drivers/slirp_kern.c
@@ -15,7 +15,7 @@ struct slirp_init {
 	struct arg_list_dummy_wrapper argw;  /* XXX should be simpler... */
 };
 
-void slirp_init(struct net_device *dev, void *data)
+static void slirp_init(struct net_device *dev, void *data)
 {
 	struct uml_net_private *private;
 	struct slirp_data *spri;
diff --git a/arch/um/drivers/virt-pci.c b/arch/um/drivers/virt-pci.c
index 7699ca5f35d4..ffe2ee8a0246 100644
--- a/arch/um/drivers/virt-pci.c
+++ b/arch/um/drivers/virt-pci.c
@@ -544,6 +544,7 @@ static void um_pci_irq_vq_cb(struct virtqueue *vq)
 	}
 }
 
+#ifdef CONFIG_OF
 /* Copied from arch/x86/kernel/devicetree.c */
 struct device_node *pcibios_get_phb_of_node(struct pci_bus *bus)
 {
@@ -562,6 +563,7 @@ struct device_node *pcibios_get_phb_of_node(struct pci_bus *bus)
 	}
 	return NULL;
 }
+#endif
 
 static int um_pci_init_vqs(struct um_pci_device *dev)
 {
diff --git a/arch/um/drivers/xterm_kern.c b/arch/um/drivers/xterm_kern.c
index 50f11b7b4774..8011e51993d5 100644
--- a/arch/um/drivers/xterm_kern.c
+++ b/arch/um/drivers/xterm_kern.c
@@ -9,6 +9,7 @@
 #include <asm/irq.h>
 #include <irq_kern.h>
 #include <os.h>
+#include "xterm.h"
 
 struct xterm_wait {
 	struct completion ready;
diff --git a/arch/um/include/shared/irq_kern.h b/arch/um/include/shared/irq_kern.h
index f2dc817abb7c..44357fa6ee29 100644
--- a/arch/um/include/shared/irq_kern.h
+++ b/arch/um/include/shared/irq_kern.h
@@ -76,4 +76,5 @@ static inline bool um_irq_timetravel_handler_used(void)
 }
 
 void um_free_irq(int irq, void *dev_id);
+void free_irqs(void);
 #endif
diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c
index a8873d9bc28b..635d44606bfe 100644
--- a/arch/um/kernel/irq.c
+++ b/arch/um/kernel/irq.c
@@ -23,8 +23,6 @@
 #include <linux/time-internal.h>
 
 
-extern void free_irqs(void);
-
 /* When epoll triggers we do not know why it did so
  * we can also have different IRQs for read and write.
  * This is why we keep a small irq_reg array for each fd -
diff --git a/arch/x86/um/Makefile b/arch/x86/um/Makefile
index ee89f6bb9242..8bc72a51b257 100644
--- a/arch/x86/um/Makefile
+++ b/arch/x86/um/Makefile
@@ -13,15 +13,16 @@ obj-y = bugs_$(BITS).o delay.o fault.o ldt.o \
 	ptrace_$(BITS).o ptrace_user.o setjmp_$(BITS).o signal.o \
 	stub_$(BITS).o stub_segv.o \
 	sys_call_table_$(BITS).o sysrq_$(BITS).o tls_$(BITS).o \
-	mem_$(BITS).o subarch.o os-$(OS)/
+	mem_$(BITS).o subarch.o os-Linux/
 
 ifeq ($(CONFIG_X86_32),y)
 
-obj-y += checksum_32.o syscalls_32.o
+obj-y += syscalls_32.o
 obj-$(CONFIG_ELF_CORE) += elfcore.o
 
 subarch-y = ../lib/string_32.o ../lib/atomic64_32.o ../lib/atomic64_cx8_32.o
 subarch-y += ../lib/cmpxchg8b_emu.o ../lib/atomic64_386_32.o
+subarch-y += ../lib/checksum_32.o
 subarch-y += ../kernel/sys_ia32.o
 
 else
diff --git a/arch/x86/um/asm/mm_context.h b/arch/x86/um/asm/mm_context.h
index 4a73d63e4760..dc32dc023c2f 100644
--- a/arch/x86/um/asm/mm_context.h
+++ b/arch/x86/um/asm/mm_context.h
@@ -11,8 +11,6 @@
 #include <linux/mutex.h>
 #include <asm/ldt.h>
 
-extern void ldt_host_info(void);
-
 #define LDT_PAGES_MAX \
 	((LDT_ENTRIES * LDT_ENTRY_SIZE)/PAGE_SIZE)
 #define LDT_ENTRIES_PER_PAGE \
diff --git a/arch/x86/um/checksum_32.S b/arch/x86/um/checksum_32.S
deleted file mode 100644
index aed782ab7721..000000000000
--- a/arch/x86/um/checksum_32.S
+++ /dev/null
@@ -1,214 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/*
- * INET		An implementation of the TCP/IP protocol suite for the LINUX
- *		operating system.  INET is implemented using the  BSD Socket
- *		interface as the means of communication with the user level.
- *
- *		IP/TCP/UDP checksumming routines
- *
- * Authors:	Jorge Cwik, <jorge@laser.satlink.net>
- *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
- *		Tom May, <ftom@netcom.com>
- *              Pentium Pro/II routines:
- *              Alexander Kjeldaas <astor@guardian.no>
- *              Finn Arne Gangstad <finnag@guardian.no>
- *		Lots of code moved from tcp.c and ip.c; see those files
- *		for more names.
- *
- * Changes:     Ingo Molnar, converted csum_partial_copy() to 2.1 exception
- *			     handling.
- *		Andi Kleen,  add zeroing on error
- *                   converted to pure assembler
- */
-
-#include <asm/errno.h>
-#include <asm/asm.h>
-#include <asm/export.h>
-				
-/*
- * computes a partial checksum, e.g. for TCP/UDP fragments
- */
-
-/*	
-unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum)
- */
-		
-.text
-.align 4
-.globl csum_partial
-		
-#ifndef CONFIG_X86_USE_PPRO_CHECKSUM
-
-	  /*		
-	   * Experiments with Ethernet and SLIP connections show that buff
-	   * is aligned on either a 2-byte or 4-byte boundary.  We get at
-	   * least a twofold speedup on 486 and Pentium if it is 4-byte aligned.
-	   * Fortunately, it is easy to convert 2-byte alignment to 4-byte
-	   * alignment for the unrolled loop.
-	   */		
-csum_partial:
-	pushl %esi
-	pushl %ebx
-	movl 20(%esp),%eax	# Function arg: unsigned int sum
-	movl 16(%esp),%ecx	# Function arg: int len
-	movl 12(%esp),%esi	# Function arg: unsigned char *buff
-	testl $2, %esi		# Check alignment.
-	jz 2f			# Jump if alignment is ok.
-	subl $2, %ecx		# Alignment uses up two bytes.
-	jae 1f			# Jump if we had at least two bytes.
-	addl $2, %ecx		# ecx was < 2.  Deal with it.
-	jmp 4f
-1:	movw (%esi), %bx
-	addl $2, %esi
-	addw %bx, %ax
-	adcl $0, %eax
-2:
-	movl %ecx, %edx
-	shrl $5, %ecx
-	jz 2f
-	testl %esi, %esi
-1:	movl (%esi), %ebx
-	adcl %ebx, %eax
-	movl 4(%esi), %ebx
-	adcl %ebx, %eax
-	movl 8(%esi), %ebx
-	adcl %ebx, %eax
-	movl 12(%esi), %ebx
-	adcl %ebx, %eax
-	movl 16(%esi), %ebx
-	adcl %ebx, %eax
-	movl 20(%esi), %ebx
-	adcl %ebx, %eax
-	movl 24(%esi), %ebx
-	adcl %ebx, %eax
-	movl 28(%esi), %ebx
-	adcl %ebx, %eax
-	lea 32(%esi), %esi
-	dec %ecx
-	jne 1b
-	adcl $0, %eax
-2:	movl %edx, %ecx
-	andl $0x1c, %edx
-	je 4f
-	shrl $2, %edx		# This clears CF
-3:	adcl (%esi), %eax
-	lea 4(%esi), %esi
-	dec %edx
-	jne 3b
-	adcl $0, %eax
-4:	andl $3, %ecx
-	jz 7f
-	cmpl $2, %ecx
-	jb 5f
-	movw (%esi),%cx
-	leal 2(%esi),%esi
-	je 6f
-	shll $16,%ecx
-5:	movb (%esi),%cl
-6:	addl %ecx,%eax
-	adcl $0, %eax 
-7:	
-	popl %ebx
-	popl %esi
-	RET
-
-#else
-
-/* Version for PentiumII/PPro */
-
-csum_partial:
-	pushl %esi
-	pushl %ebx
-	movl 20(%esp),%eax	# Function arg: unsigned int sum
-	movl 16(%esp),%ecx	# Function arg: int len
-	movl 12(%esp),%esi	# Function arg:	const unsigned char *buf
-
-	testl $2, %esi         
-	jnz 30f                 
-10:
-	movl %ecx, %edx
-	movl %ecx, %ebx
-	andl $0x7c, %ebx
-	shrl $7, %ecx
-	addl %ebx,%esi
-	shrl $2, %ebx  
-	negl %ebx
-	lea 45f(%ebx,%ebx,2), %ebx
-	testl %esi, %esi
-	jmp *%ebx
-
-	# Handle 2-byte-aligned regions
-20:	addw (%esi), %ax
-	lea 2(%esi), %esi
-	adcl $0, %eax
-	jmp 10b
-
-30:	subl $2, %ecx          
-	ja 20b                 
-	je 32f
-	movzbl (%esi),%ebx	# csumming 1 byte, 2-aligned
-	addl %ebx, %eax
-	adcl $0, %eax
-	jmp 80f
-32:
-	addw (%esi), %ax	# csumming 2 bytes, 2-aligned
-	adcl $0, %eax
-	jmp 80f
-
-40: 
-	addl -128(%esi), %eax
-	adcl -124(%esi), %eax
-	adcl -120(%esi), %eax
-	adcl -116(%esi), %eax   
-	adcl -112(%esi), %eax   
-	adcl -108(%esi), %eax
-	adcl -104(%esi), %eax
-	adcl -100(%esi), %eax
-	adcl -96(%esi), %eax
-	adcl -92(%esi), %eax
-	adcl -88(%esi), %eax
-	adcl -84(%esi), %eax
-	adcl -80(%esi), %eax
-	adcl -76(%esi), %eax
-	adcl -72(%esi), %eax
-	adcl -68(%esi), %eax
-	adcl -64(%esi), %eax     
-	adcl -60(%esi), %eax     
-	adcl -56(%esi), %eax     
-	adcl -52(%esi), %eax   
-	adcl -48(%esi), %eax   
-	adcl -44(%esi), %eax
-	adcl -40(%esi), %eax
-	adcl -36(%esi), %eax
-	adcl -32(%esi), %eax
-	adcl -28(%esi), %eax
-	adcl -24(%esi), %eax
-	adcl -20(%esi), %eax
-	adcl -16(%esi), %eax
-	adcl -12(%esi), %eax
-	adcl -8(%esi), %eax
-	adcl -4(%esi), %eax
-45:
-	lea 128(%esi), %esi
-	adcl $0, %eax
-	dec %ecx
-	jge 40b
-	movl %edx, %ecx
-50:	andl $3, %ecx
-	jz 80f
-
-	# Handle the last 1-3 bytes without jumping
-	notl %ecx		# 1->2, 2->1, 3->0, higher bits are masked
-	movl $0xffffff,%ebx	# by the shll and shrl instructions
-	shll $3,%ecx
-	shrl %cl,%ebx
-	andl -128(%esi),%ebx	# esi is 4-aligned so should be ok
-	addl %ebx,%eax
-	adcl $0,%eax
-80: 
-	popl %ebx
-	popl %esi
-	RET
-				
-#endif
-	EXPORT_SYMBOL(csum_partial)
diff --git a/include/asm-generic/current.h b/include/asm-generic/current.h
index 3a2e224b9fa0..9c2aeecbd05a 100644
--- a/include/asm-generic/current.h
+++ b/include/asm-generic/current.h
@@ -2,9 +2,11 @@
 #ifndef __ASM_GENERIC_CURRENT_H
 #define __ASM_GENERIC_CURRENT_H
 
+#ifndef __ASSEMBLY__
 #include <linux/thread_info.h>
 
 #define get_current() (current_thread_info()->task)
 #define current get_current()
+#endif
 
 #endif /* __ASM_GENERIC_CURRENT_H */
diff --git a/sound/Kconfig b/sound/Kconfig
index f0e15822e858..4c036a9a420a 100644
--- a/sound/Kconfig
+++ b/sound/Kconfig
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 menuconfig SOUND
 	tristate "Sound card support"
-	depends on HAS_IOMEM
+	depends on HAS_IOMEM || UML
 	help
 	  If you have a sound card in your computer, i.e. if it can say more
 	  than an occasional beep, say Y.