Merge tag 'for-linus-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml

Pull UML updates from Richard Weinberger:

 - set_fs removal

 - Devicetree support

 - Many cleanups from Al

 - Various virtio and build related fixes

* tag 'for-linus-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml: (31 commits)
  um: virtio_uml: Allow probing from devicetree
  um: Add devicetree support
  um: Extract load file helper from initrd.c
  um: remove set_fs
  hostfs: Fix writeback of dirty pages
  um: Use swap() to make code cleaner
  um: header debriding - sigio.h
  um: header debriding - os.h
  um: header debriding - net_*.h
  um: header debriding - mem_user.h
  um: header debriding - activate_ipi()
  um: common-offsets.h debriding...
  um, x86: bury crypto_tfm_ctx_offset
  um: unexport handle_page_fault()
  um: remove a dangling extern of syscall_trace()
  um: kill unused cpu()
  uml/i386: missing include in barrier.h
  um: stop polluting the namespace with registers.h contents
  logic_io instance of iounmap() needs volatile on argument
  um: move amd64 variant of mmap(2) to arch/x86/um/syscalls_64.c
  ...

36 files changed, 230 insertions, 186 deletions

diff --git a/arch/um/.gitignore b/arch/um/.gitignore
index 6323e5571887..d69ea5b562ce 100644
--- a/arch/um/.gitignore
+++ b/arch/um/.gitignore
@@ -2,3 +2,4 @@
 kernel/config.c
 kernel/config.tmp
 kernel/vmlinux.lds
+kernel/capflags.c
diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index c18b45f75d41..b233db4f42b2 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -18,10 +18,10 @@ config UML
 	select HAVE_DEBUG_KMEMLEAK
 	select HAVE_DEBUG_BUGVERBOSE
 	select NO_DMA if !UML_DMA_EMULATION
+	select OF_EARLY_FLATTREE if OF
 	select GENERIC_IRQ_SHOW
 	select GENERIC_CPU_DEVICES
 	select HAVE_GCC_PLUGINS
-	select SET_FS
 	select TRACE_IRQFLAGS_SUPPORT
 	select TTY # Needed for line.c
 	select HAVE_ARCH_VMAP_STACK
diff --git a/arch/um/drivers/virt-pci.c b/arch/um/drivers/virt-pci.c
index c08066633023..0ab58016db22 100644
--- a/arch/um/drivers/virt-pci.c
+++ b/arch/um/drivers/virt-pci.c
@@ -181,15 +181,15 @@ static unsigned long um_pci_cfgspace_read(void *priv, unsigned int offset,
 	/* buf->data is maximum size - we may only use parts of it */
 	struct um_pci_message_buffer *buf;
 	u8 *data;
-	unsigned long ret = ~0ULL;
+	unsigned long ret = ULONG_MAX;
 
 	if (!dev)
-		return ~0ULL;
+		return ULONG_MAX;
 
 	buf = get_cpu_var(um_pci_msg_bufs);
 	data = buf->data;
 
-	memset(data, 0xff, sizeof(data));
+	memset(buf->data, 0xff, sizeof(buf->data));
 
 	switch (size) {
 	case 1:
@@ -304,7 +304,7 @@ static unsigned long um_pci_bar_read(void *priv, unsigned int offset,
 	/* buf->data is maximum size - we may only use parts of it */
 	struct um_pci_message_buffer *buf;
 	u8 *data;
-	unsigned long ret = ~0ULL;
+	unsigned long ret = ULONG_MAX;
 
 	buf = get_cpu_var(um_pci_msg_bufs);
 	data = buf->data;
diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c
index d51e445df797..ba562d68dc04 100644
--- a/arch/um/drivers/virtio_uml.c
+++ b/arch/um/drivers/virtio_uml.c
@@ -21,6 +21,7 @@
  * Based on Virtio MMIO driver by Pawel Moll, copyright 2011-2014, ARM Ltd.
  */
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/virtio.h>
@@ -49,6 +50,7 @@ struct virtio_uml_platform_data {
 struct virtio_uml_device {
 	struct virtio_device vdev;
 	struct platform_device *pdev;
+	struct virtio_uml_platform_data *pdata;
 
 	spinlock_t sock_lock;
 	int sock, req_fd, irq;
@@ -149,7 +151,7 @@ static int vhost_user_recv(struct virtio_uml_device *vu_dev,
 	if (rc == -ECONNRESET && vu_dev->registered) {
 		struct virtio_uml_platform_data *pdata;
 
-		pdata = vu_dev->pdev->dev.platform_data;
+		pdata = vu_dev->pdata;
 
 		virtio_break_device(&vu_dev->vdev);
 		schedule_work(&pdata->conn_broken_wk);
@@ -1090,6 +1092,8 @@ static void virtio_uml_release_dev(struct device *d)
 			container_of(d, struct virtio_device, dev);
 	struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
 
+	time_travel_propagate_time();
+
 	/* might not have been opened due to not negotiating the feature */
 	if (vu_dev->req_fd >= 0) {
 		um_free_irq(vu_dev->irq, vu_dev);
@@ -1113,21 +1117,63 @@ void virtio_uml_set_no_vq_suspend(struct virtio_device *vdev,
 		 no_vq_suspend ? "dis" : "en");
 }
 
+static void vu_of_conn_broken(struct work_struct *wk)
+{
+	/*
+	 * We can't remove the device from the devicetree so the only thing we
+	 * can do is warn.
+	 */
+	WARN_ON(1);
+}
+
 /* Platform device */
 
+static struct virtio_uml_platform_data *
+virtio_uml_create_pdata(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct virtio_uml_platform_data *pdata;
+	int ret;
+
+	if (!np)
+		return ERR_PTR(-EINVAL);
+
+	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata)
+		return ERR_PTR(-ENOMEM);
+
+	INIT_WORK(&pdata->conn_broken_wk, vu_of_conn_broken);
+	pdata->pdev = pdev;
+
+	ret = of_property_read_string(np, "socket-path", &pdata->socket_path);
+	if (ret)
+		return ERR_PTR(ret);
+
+	ret = of_property_read_u32(np, "virtio-device-id",
+				   &pdata->virtio_device_id);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return pdata;
+}
+
 static int virtio_uml_probe(struct platform_device *pdev)
 {
 	struct virtio_uml_platform_data *pdata = pdev->dev.platform_data;
 	struct virtio_uml_device *vu_dev;
 	int rc;
 
-	if (!pdata)
-		return -EINVAL;
+	if (!pdata) {
+		pdata = virtio_uml_create_pdata(pdev);
+		if (IS_ERR(pdata))
+			return PTR_ERR(pdata);
+	}
 
 	vu_dev = kzalloc(sizeof(*vu_dev), GFP_KERNEL);
 	if (!vu_dev)
 		return -ENOMEM;
 
+	vu_dev->pdata = pdata;
 	vu_dev->vdev.dev.parent = &pdev->dev;
 	vu_dev->vdev.dev.release = virtio_uml_release_dev;
 	vu_dev->vdev.config = &virtio_uml_config_ops;
@@ -1136,6 +1182,8 @@ static int virtio_uml_probe(struct platform_device *pdev)
 	vu_dev->pdev = pdev;
 	vu_dev->req_fd = -1;
 
+	time_travel_propagate_time();
+
 	do {
 		rc = os_connect_socket(pdata->socket_path);
 	} while (rc == -EINTR);
diff --git a/arch/um/include/asm/delay.h b/arch/um/include/asm/delay.h
index 56fc2b8f2dd0..e79b2ab6f40c 100644
--- a/arch/um/include/asm/delay.h
+++ b/arch/um/include/asm/delay.h
@@ -14,7 +14,7 @@ static inline void um_ndelay(unsigned long nsecs)
 	ndelay(nsecs);
 }
 #undef ndelay
-#define ndelay um_ndelay
+#define ndelay(n) um_ndelay(n)
 
 static inline void um_udelay(unsigned long usecs)
 {
@@ -26,5 +26,5 @@ static inline void um_udelay(unsigned long usecs)
 	udelay(usecs);
 }
 #undef udelay
-#define udelay um_udelay
+#define udelay(n) um_udelay(n)
 #endif /* __UM_DELAY_H */
diff --git a/arch/um/include/asm/irqflags.h b/arch/um/include/asm/irqflags.h
index dab5744e9253..1e69ef5bc35e 100644
--- a/arch/um/include/asm/irqflags.h
+++ b/arch/um/include/asm/irqflags.h
@@ -3,7 +3,7 @@
 #define __UM_IRQFLAGS_H
 
 extern int signals_enabled;
-int set_signals(int enable);
+int um_set_signals(int enable);
 void block_signals(void);
 void unblock_signals(void);
 
@@ -16,7 +16,7 @@ static inline unsigned long arch_local_save_flags(void)
 #define arch_local_irq_restore arch_local_irq_restore
 static inline void arch_local_irq_restore(unsigned long flags)
 {
-	set_signals(flags);
+	um_set_signals(flags);
 }
 
 #define arch_local_irq_enable arch_local_irq_enable
diff --git a/arch/um/include/asm/processor-generic.h b/arch/um/include/asm/processor-generic.h
index 579692a40a55..6a4fe8b4e686 100644
--- a/arch/um/include/asm/processor-generic.h
+++ b/arch/um/include/asm/processor-generic.h
@@ -11,7 +11,6 @@ struct pt_regs;
 struct task_struct;
 
 #include <asm/ptrace.h>
-#include <registers.h>
 #include <sysdep/archsetjmp.h>
 
 #include <linux/prefetch.h>
@@ -105,6 +104,7 @@ extern struct cpuinfo_um boot_cpu_data;
 #define current_cpu_data boot_cpu_data
 #define cache_line_size()	(boot_cpu_data.cache_alignment)
 
+extern unsigned long get_thread_reg(int reg, jmp_buf *buf);
 #define KSTK_REG(tsk, reg) get_thread_reg(reg, &tsk->thread.switch_buf)
 extern unsigned long __get_wchan(struct task_struct *p);
 
diff --git a/arch/um/include/asm/thread_info.h b/arch/um/include/asm/thread_info.h
index 3b1cb8b3b186..1395cbd7e340 100644
--- a/arch/um/include/asm/thread_info.h
+++ b/arch/um/include/asm/thread_info.h
@@ -22,9 +22,6 @@ struct thread_info {
 	__u32			cpu;		/* current CPU */
 	int			preempt_count;  /* 0 => preemptable,
 						   <0 => BUG */
-	mm_segment_t		addr_limit;	/* thread address space:
-					 	   0-0xBFFFFFFF for user
-						   0-0xFFFFFFFF for kernel */
 	struct thread_info	*real_thread;    /* Points to non-IRQ stack */
 	unsigned long aux_fp_regs[FP_SIZE];	/* auxiliary fp_regs to save/restore
 						   them out-of-band */
@@ -36,7 +33,6 @@ struct thread_info {
 	.flags =		0,		\
 	.cpu =		0,			\
 	.preempt_count = INIT_PREEMPT_COUNT,	\
-	.addr_limit =	KERNEL_DS,		\
 	.real_thread = NULL,			\
 }
 
diff --git a/arch/um/include/asm/uaccess.h b/arch/um/include/asm/uaccess.h
index 191ef36dd543..17d18cfd82a5 100644
--- a/arch/um/include/asm/uaccess.h
+++ b/arch/um/include/asm/uaccess.h
@@ -8,6 +8,7 @@
 #define __UM_UACCESS_H
 
 #include <asm/elf.h>
+#include <asm/unaligned.h>
 
 #define __under_task_size(addr, size) \
 	(((unsigned long) (addr) < TASK_SIZE) && \
@@ -39,8 +40,24 @@ static inline int __access_ok(unsigned long addr, unsigned long size)
 {
 	return __addr_range_nowrap(addr, size) &&
 		(__under_task_size(addr, size) ||
-		__access_ok_vsyscall(addr, size) ||
-		uaccess_kernel());
+		 __access_ok_vsyscall(addr, size));
 }
 
+/* no pagefaults for kernel addresses in um */
+#define HAVE_GET_KERNEL_NOFAULT 1
+
+#define __get_kernel_nofault(dst, src, type, err_label)			\
+do {									\
+	*((type *)dst) = get_unaligned((type *)(src));			\
+	if (0) /* make sure the label looks used to the compiler */	\
+		goto err_label;						\
+} while (0)
+
+#define __put_kernel_nofault(dst, src, type, err_label)			\
+do {									\
+	put_unaligned(*((type *)src), (type *)(dst));			\
+	if (0) /* make sure the label looks used to the compiler */	\
+		goto err_label;						\
+} while (0)
+
 #endif
diff --git a/arch/um/include/shared/common-offsets.h b/arch/um/include/shared/common-offsets.h
index edc90ab73734..96195483fbd0 100644
--- a/arch/um/include/shared/common-offsets.h
+++ b/arch/um/include/shared/common-offsets.h
@@ -9,32 +9,17 @@ DEFINE(UM_KERN_PAGE_MASK, PAGE_MASK);
 DEFINE(UM_KERN_PAGE_SHIFT, PAGE_SHIFT);
 DEFINE(UM_NSEC_PER_SEC, NSEC_PER_SEC);
 
-DEFINE(UM_ELF_CLASS, ELF_CLASS);
-DEFINE(UM_ELFCLASS32, ELFCLASS32);
-DEFINE(UM_ELFCLASS64, ELFCLASS64);
-
-DEFINE(UM_NR_CPUS, NR_CPUS);
-
 DEFINE(UM_GFP_KERNEL, GFP_KERNEL);
 DEFINE(UM_GFP_ATOMIC, GFP_ATOMIC);
 
-/* For crypto assembler code. */
-DEFINE(crypto_tfm_ctx_offset, offsetof(struct crypto_tfm, __crt_ctx));
-
 DEFINE(UM_THREAD_SIZE, THREAD_SIZE);
 
-DEFINE(UM_HZ, HZ);
-
-DEFINE(UM_USEC_PER_SEC, USEC_PER_SEC);
 DEFINE(UM_NSEC_PER_SEC, NSEC_PER_SEC);
 DEFINE(UM_NSEC_PER_USEC, NSEC_PER_USEC);
 
 #ifdef CONFIG_PRINTK
 DEFINE(UML_CONFIG_PRINTK, CONFIG_PRINTK);
 #endif
-#ifdef CONFIG_NO_HZ_COMMON
-DEFINE(UML_CONFIG_NO_HZ_COMMON, CONFIG_NO_HZ_COMMON);
-#endif
 #ifdef CONFIG_UML_X86
 DEFINE(UML_CONFIG_UML_X86, CONFIG_UML_X86);
 #endif
diff --git a/arch/um/include/shared/irq_user.h b/arch/um/include/shared/irq_user.h
index 86a8a573b65c..da0f6eea30d0 100644
--- a/arch/um/include/shared/irq_user.h
+++ b/arch/um/include/shared/irq_user.h
@@ -20,6 +20,5 @@ 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);
-extern int activate_ipi(int fd, int pid);
 
 #endif
diff --git a/arch/um/include/shared/kern_util.h b/arch/um/include/shared/kern_util.h
index a2cfd42608a0..d8b8b4f07e42 100644
--- a/arch/um/include/shared/kern_util.h
+++ b/arch/um/include/shared/kern_util.h
@@ -53,13 +53,11 @@ extern void do_uml_exitcalls(void);
 extern int __cant_sleep(void);
 extern int get_current_pid(void);
 extern int copy_from_user_proc(void *to, void *from, int size);
-extern int cpu(void);
 extern char *uml_strdup(const char *string);
 
 extern unsigned long to_irq_stack(unsigned long *mask_out);
 extern unsigned long from_irq_stack(int nested);
 
-extern void syscall_trace(struct uml_pt_regs *regs, int entryexit);
 extern int singlestepping(void *t);
 
 extern void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs);
diff --git a/arch/um/include/shared/longjmp.h b/arch/um/include/shared/longjmp.h
index bdb2869b72b3..8863319039f3 100644
--- a/arch/um/include/shared/longjmp.h
+++ b/arch/um/include/shared/longjmp.h
@@ -18,7 +18,7 @@ extern void longjmp(jmp_buf, int);
 	enable = *(volatile int *)&signals_enabled;	\
 	n = setjmp(*buf);				\
 	if(n != 0)					\
-		set_signals_trace(enable);		\
+		um_set_signals_trace(enable);		\
 	n; })
 
 #endif
diff --git a/arch/um/include/shared/mem_user.h b/arch/um/include/shared/mem_user.h
index cb84414e3e66..11a723a58545 100644
--- a/arch/um/include/shared/mem_user.h
+++ b/arch/um/include/shared/mem_user.h
@@ -46,16 +46,11 @@ extern int iomem_size;
 
 #define ROUND_4M(n) ((((unsigned long) (n)) + (1 << 22)) & ~((1 << 22) - 1))
 
-extern int init_mem_user(void);
-extern void setup_memory(void *entry);
 extern unsigned long find_iomem(char *driver, unsigned long *len_out);
 extern void mem_total_pages(unsigned long physmem, unsigned long iomem,
 		     unsigned long highmem);
-extern unsigned long get_vm(unsigned long len);
 extern void setup_physmem(unsigned long start, unsigned long usable,
 			  unsigned long len, unsigned long long highmem);
-extern void add_iomem(char *name, int fd, unsigned long size);
-extern unsigned long phys_offset(unsigned long phys);
 extern void map_memory(unsigned long virt, unsigned long phys,
 		       unsigned long len, int r, int w, int x);
 
diff --git a/arch/um/include/shared/net_kern.h b/arch/um/include/shared/net_kern.h
index a87be13c5b87..441a8a309329 100644
--- a/arch/um/include/shared/net_kern.h
+++ b/arch/um/include/shared/net_kern.h
@@ -59,8 +59,6 @@ struct transport {
 	const int setup_size;
 };
 
-extern struct net_device *ether_init(int);
-extern unsigned short ether_protocol(struct sk_buff *);
 extern int tap_setup_common(char *str, char *type, char **dev_name,
 			    char **mac_out, char **gate_addr);
 extern void register_transport(struct transport *new);
diff --git a/arch/um/include/shared/net_user.h b/arch/um/include/shared/net_user.h
index 1b0531769a5e..ba92a4d93531 100644
--- a/arch/um/include/shared/net_user.h
+++ b/arch/um/include/shared/net_user.h
@@ -24,7 +24,6 @@ struct net_user_info {
 	int mtu;
 };
 
-extern void ether_user_init(void *data, void *dev);
 extern void iter_addresses(void *d, void (*cb)(unsigned char *,
 					       unsigned char *, void *),
 			   void *arg);
diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h
index 96d400387c93..00214059d9ec 100644
--- a/arch/um/include/shared/os.h
+++ b/arch/um/include/shared/os.h
@@ -159,20 +159,11 @@ 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 void os_close_file(int fd);
 extern int os_rcv_fd(int fd, int *helper_pid_out);
-extern int create_unix_socket(char *file, int len, int close_on_exec);
 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 int os_stat_filesystem(char *path, long *bsize_out,
-			      long long *blocks_out, long long *bfree_out,
-			      long long *bavail_out, long long *files_out,
-			      long long *ffree_out, void *fsid_out,
-			      int fsid_size, long *namelen_out,
-			      long *spare_out);
-extern int os_change_dir(char *dir);
-extern int os_fchange_dir(int fd);
 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);
@@ -232,14 +223,13 @@ 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 remove_sigstack(void);
 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 set_signals(int enable);
-extern int set_signals_trace(int enable);
+extern int um_set_signals(int enable);
+extern int um_set_signals_trace(int enable);
 extern int os_is_signal_stack(void);
 extern void deliver_alarm(void);
 extern void register_pm_wake_signal(void);
@@ -266,7 +256,6 @@ 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);
 
@@ -290,8 +279,6 @@ extern int is_skas_winch(int pid, int fd, void *data);
 extern int start_userspace(unsigned long stub_stack);
 extern int copy_context_skas0(unsigned long stack, int pid);
 extern void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs);
-extern int map_stub_pages(int fd, unsigned long code, unsigned long data,
-			  unsigned long stack);
 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);
diff --git a/arch/um/include/shared/registers.h b/arch/um/include/shared/registers.h
index 0c50fa6e8a55..2f9c3ce5b45e 100644
--- a/arch/um/include/shared/registers.h
+++ b/arch/um/include/shared/registers.h
@@ -7,7 +7,6 @@
 #define __REGISTERS_H
 
 #include <sysdep/ptrace.h>
-#include <sysdep/archsetjmp.h>
 
 extern int save_i387_registers(int pid, unsigned long *fp_regs);
 extern int restore_i387_registers(int pid, unsigned long *fp_regs);
@@ -16,10 +15,9 @@ extern int restore_fp_registers(int pid, unsigned long *fp_regs);
 extern int save_fpx_registers(int pid, unsigned long *fp_regs);
 extern int restore_fpx_registers(int pid, unsigned long *fp_regs);
 extern int save_registers(int pid, struct uml_pt_regs *regs);
-extern int restore_registers(int pid, struct uml_pt_regs *regs);
-extern int init_registers(int pid);
+extern int restore_pid_registers(int pid, struct uml_pt_regs *regs);
+extern int init_pid_registers(int pid);
 extern void get_safe_registers(unsigned long *regs, unsigned long *fp_regs);
-extern unsigned long get_thread_reg(int reg, jmp_buf *buf);
 extern int get_fp_registers(int pid, unsigned long *regs);
 extern int put_fp_registers(int pid, unsigned long *regs);
 
diff --git a/arch/um/include/shared/sigio.h b/arch/um/include/shared/sigio.h
index 8fe8f57c05de..e60c8b227844 100644
--- a/arch/um/include/shared/sigio.h
+++ b/arch/um/include/shared/sigio.h
@@ -7,7 +7,6 @@
 #define __SIGIO_H__
 
 extern int write_sigio_irq(int fd);
-extern int register_sigio_fd(int fd);
 extern void sigio_lock(void);
 extern void sigio_unlock(void);
 
diff --git a/arch/um/kernel/Makefile b/arch/um/kernel/Makefile
index 1d18e4e46989..1c2d4b29a3d4 100644
--- a/arch/um/kernel/Makefile
+++ b/arch/um/kernel/Makefile
@@ -16,11 +16,13 @@ extra-y := vmlinux.lds
 
 obj-y = config.o exec.o exitcode.o irq.o ksyms.o mem.o \
 	physmem.o process.o ptrace.o reboot.o sigio.o \
-	signal.o syscall.o sysrq.o time.o tlb.o trap.o \
+	signal.o sysrq.o time.o tlb.o trap.o \
 	um_arch.o umid.o maccess.o kmsg_dump.o capflags.o skas/
+obj-y += load_file.o
 
 obj-$(CONFIG_BLK_DEV_INITRD) += initrd.o
 obj-$(CONFIG_GPROF)	+= gprof_syms.o
+obj-$(CONFIG_OF) += dtb.o
 obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
 obj-$(CONFIG_STACKTRACE) += stacktrace.o
 obj-$(CONFIG_GENERIC_PCI_IOMAP) += ioport.o
diff --git a/arch/um/kernel/dtb.c b/arch/um/kernel/dtb.c
new file mode 100644
index 000000000000..ca69d72025f3
--- /dev/null
+++ b/arch/um/kernel/dtb.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/init.h>
+#include <linux/of_fdt.h>
+#include <linux/printk.h>
+#include <linux/memblock.h>
+#include <init.h>
+
+#include "um_arch.h"
+
+static char *dtb __initdata;
+
+void uml_dtb_init(void)
+{
+	long long size;
+	void *area;
+
+	area = uml_load_file(dtb, &size);
+	if (!area)
+		return;
+
+	if (!early_init_dt_scan(area)) {
+		pr_err("invalid DTB %s\n", dtb);
+		memblock_free(area, size);
+		return;
+	}
+
+	unflatten_device_tree();
+	early_init_fdt_scan_reserved_mem();
+}
+
+static int __init uml_dtb_setup(char *line, int *add)
+{
+	dtb = line;
+	return 0;
+}
+
+__uml_setup("dtb=", uml_dtb_setup,
+"dtb=<file>\n"
+"    Boot the kernel with the devicetree blob from the specified file.\n"
+);
diff --git a/arch/um/kernel/exec.c b/arch/um/kernel/exec.c
index 4d8498100341..c85e40c72779 100644
--- a/arch/um/kernel/exec.c
+++ b/arch/um/kernel/exec.c
@@ -16,6 +16,7 @@
 #include <linux/uaccess.h>
 #include <as-layout.h>
 #include <mem_user.h>
+#include <registers.h>
 #include <skas.h>
 #include <os.h>
 
diff --git a/arch/um/kernel/initrd.c b/arch/um/kernel/initrd.c
index c1981ffb7179..47b8cb1a1156 100644
--- a/arch/um/kernel/initrd.c
+++ b/arch/um/kernel/initrd.c
@@ -10,37 +10,21 @@
 #include <init.h>
 #include <os.h>
 
+#include "um_arch.h"
+
 /* Changed by uml_initrd_setup, which is a setup */
 static char *initrd __initdata = NULL;
-static int load_initrd(char *filename, void *buf, int size);
 
 int __init read_initrd(void)
 {
+	unsigned long long size;
 	void *area;
-	long long size;
-	int err;
-
-	if (initrd == NULL)
-		return 0;
 
-	err = os_file_size(initrd, &size);
-	if (err)
+	if (!initrd)
 		return 0;
 
-	/*
-	 * This is necessary because alloc_bootmem craps out if you
-	 * ask for no memory.
-	 */
-	if (size == 0) {
-		printk(KERN_ERR "\"%s\" is a zero-size initrd\n", initrd);
-		return 0;
-	}
-
-	area = memblock_alloc(size, SMP_CACHE_BYTES);
+	area = uml_load_file(initrd, &size);
 	if (!area)
-		panic("%s: Failed to allocate %llu bytes\n", __func__, size);
-
-	if (load_initrd(initrd, area, size) == -1)
 		return 0;
 
 	initrd_start = (unsigned long) area;
@@ -59,25 +43,3 @@ __uml_setup("initrd=", uml_initrd_setup,
 "    This is used to boot UML from an initrd image.  The argument is the\n"
 "    name of the file containing the image.\n\n"
 );
-
-static int load_initrd(char *filename, void *buf, int size)
-{
-	int fd, n;
-
-	fd = os_open_file(filename, of_read(OPENFLAGS()), 0);
-	if (fd < 0) {
-		printk(KERN_ERR "Opening '%s' failed - err = %d\n", filename,
-		       -fd);
-		return -1;
-	}
-	n = os_read_file(fd, buf, size);
-	if (n != size) {
-		printk(KERN_ERR "Read of %d bytes from '%s' failed, "
-		       "err = %d\n", size,
-		       filename, -n);
-		return -1;
-	}
-
-	os_close_file(fd);
-	return 0;
-}
diff --git a/arch/um/kernel/ksyms.c b/arch/um/kernel/ksyms.c
index b1e5634398d0..3a85bde3e173 100644
--- a/arch/um/kernel/ksyms.c
+++ b/arch/um/kernel/ksyms.c
@@ -6,7 +6,7 @@
 #include <linux/module.h>
 #include <os.h>
 
-EXPORT_SYMBOL(set_signals);
+EXPORT_SYMBOL(um_set_signals);
 EXPORT_SYMBOL(signals_enabled);
 
 EXPORT_SYMBOL(os_stat_fd);
diff --git a/arch/um/kernel/load_file.c b/arch/um/kernel/load_file.c
new file mode 100644
index 000000000000..5cecd0e291fb
--- /dev/null
+++ b/arch/um/kernel/load_file.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+#include <linux/memblock.h>
+#include <os.h>
+
+#include "um_arch.h"
+
+static int __init __uml_load_file(const char *filename, void *buf, int size)
+{
+	int fd, n;
+
+	fd = os_open_file(filename, of_read(OPENFLAGS()), 0);
+	if (fd < 0) {
+		printk(KERN_ERR "Opening '%s' failed - err = %d\n", filename,
+		       -fd);
+		return -1;
+	}
+	n = os_read_file(fd, buf, size);
+	if (n != size) {
+		printk(KERN_ERR "Read of %d bytes from '%s' failed, "
+		       "err = %d\n", size,
+		       filename, -n);
+		return -1;
+	}
+
+	os_close_file(fd);
+	return 0;
+}
+
+void *uml_load_file(const char *filename, unsigned long long *size)
+{
+	void *area;
+	int err;
+
+	*size = 0;
+
+	if (!filename)
+		return NULL;
+
+	err = os_file_size(filename, size);
+	if (err)
+		return NULL;
+
+	if (*size == 0) {
+		printk(KERN_ERR "\"%s\" is empty\n", filename);
+		return NULL;
+	}
+
+	area = memblock_alloc(*size, SMP_CACHE_BYTES);
+	if (!area)
+		panic("%s: Failed to allocate %llu bytes\n", __func__, *size);
+
+	if (__uml_load_file(filename, area, *size)) {
+		memblock_free(area, *size);
+		return NULL;
+	}
+
+	return area;
+}
diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index 0039771eb01c..15295c3237a0 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -85,8 +85,7 @@ static void __init one_md_table_init(pud_t *pud)
 		      __func__, PAGE_SIZE, PAGE_SIZE);
 
 	set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
-	if (pmd_table != pmd_offset(pud, 0))
-		BUG();
+	BUG_ON(pmd_table != pmd_offset(pud, 0));
 #endif
 }
 
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 82107373ac7e..4a420778ed87 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -31,6 +31,7 @@
 #include <kern_util.h>
 #include <os.h>
 #include <skas.h>
+#include <registers.h>
 #include <linux/time-internal.h>
 
 /*
@@ -263,11 +264,6 @@ int clear_user_proc(void __user *buf, int size)
 	return clear_user(buf, size);
 }
 
-int cpu(void)
-{
-	return current_thread_info()->cpu;
-}
-
 static atomic_t using_sysemu = ATOMIC_INIT(0);
 int sysemu_supported;
 
diff --git a/arch/um/kernel/skas/uaccess.c b/arch/um/kernel/skas/uaccess.c
index a509be911026..23775d01a2a6 100644
--- a/arch/um/kernel/skas/uaccess.c
+++ b/arch/um/kernel/skas/uaccess.c
@@ -146,11 +146,6 @@ static int copy_chunk_from_user(unsigned long from, int len, void *arg)
 
 unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 {
-	if (uaccess_kernel()) {
-		memcpy(to, (__force void*)from, n);
-		return 0;
-	}
-
 	return buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to);
 }
 EXPORT_SYMBOL(raw_copy_from_user);
@@ -166,11 +161,6 @@ static int copy_chunk_to_user(unsigned long to, int len, void *arg)
 
 unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 {
-	if (uaccess_kernel()) {
-		memcpy((__force void *) to, from, n);
-		return 0;
-	}
-
 	return buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from);
 }
 EXPORT_SYMBOL(raw_copy_to_user);
@@ -196,12 +186,6 @@ long strncpy_from_user(char *dst, const char __user *src, long count)
 
 	if (!access_ok(src, 1))
 		return -EFAULT;
-
-	if (uaccess_kernel()) {
-		strncpy(dst, (__force void *) src, count);
-		return strnlen(dst, count);
-	}
-
 	n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user,
 		      &ptr);
 	if (n != 0)
@@ -218,11 +202,6 @@ static int clear_chunk(unsigned long addr, int len, void *unused)
 
 unsigned long __clear_user(void __user *mem, unsigned long len)
 {
-	if (uaccess_kernel()) {
-		memset((__force void*)mem, 0, len);
-		return 0;
-	}
-
 	return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL);
 }
 EXPORT_SYMBOL(__clear_user);
@@ -245,10 +224,6 @@ long strnlen_user(const char __user *str, long len)
 
 	if (!access_ok(str, 1))
 		return -EFAULT;
-
-	if (uaccess_kernel())
-		return strnlen((__force char*)str, len) + 1;
-
 	n = buffer_op((unsigned long) str, len, 0, strnlen_chunk, &count);
 	if (n == 0)
 		return count + 1;
diff --git a/arch/um/kernel/syscall.c b/arch/um/kernel/syscall.c
deleted file mode 100644
index eed54c53fbbb..000000000000
--- a/arch/um/kernel/syscall.c
+++ /dev/null
@@ -1,28 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
- */
-
-#include <linux/file.h>
-#include <linux/fs.h>
-#include <linux/mm.h>
-#include <linux/sched.h>
-#include <linux/utsname.h>
-#include <linux/syscalls.h>
-#include <asm/current.h>
-#include <asm/mman.h>
-#include <linux/uaccess.h>
-#include <asm/unistd.h>
-
-long old_mmap(unsigned long addr, unsigned long len,
-	      unsigned long prot, unsigned long flags,
-	      unsigned long fd, unsigned long offset)
-{
-	long err = -EINVAL;
-	if (offset & ~PAGE_MASK)
-		goto out;
-
-	err = ksys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);
- out:
-	return err;
-}
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index c32efb09db21..561a2b03c3cf 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -127,7 +127,6 @@ out_of_memory:
 	pagefault_out_of_memory();
 	return 0;
 }
-EXPORT_SYMBOL(handle_page_fault);
 
 static void show_segv_info(struct uml_pt_regs *regs)
 {
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 54447690de11..abceeabe29b9 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -29,6 +29,8 @@
 #include <mem_user.h>
 #include <os.h>
 
+#include "um_arch.h"
+
 #define DEFAULT_COMMAND_LINE_ROOT "root=98:0"
 #define DEFAULT_COMMAND_LINE_CONSOLE "console=tty"
 
@@ -407,6 +409,7 @@ void __init setup_arch(char **cmdline_p)
 	stack_protections((unsigned long) &init_thread_info);
 	setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
 	mem_total_pages(physmem_size, iomem_size, highmem);
+	uml_dtb_init();
 	read_initrd();
 
 	paging_init();
diff --git a/arch/um/kernel/um_arch.h b/arch/um/kernel/um_arch.h
new file mode 100644
index 000000000000..1e07fb7ee35e
--- /dev/null
+++ b/arch/um/kernel/um_arch.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __UML_ARCH_H__
+#define __UML_ARCH_H__
+
+extern void * __init uml_load_file(const char *filename, unsigned long long *size);
+
+#ifdef CONFIG_OF
+extern void __init uml_dtb_init(void);
+#else
+static inline void uml_dtb_init(void) { }
+#endif
+
+#endif
diff --git a/arch/um/os-Linux/registers.c b/arch/um/os-Linux/registers.c
index 2d9270508e15..b123955be7ac 100644
--- a/arch/um/os-Linux/registers.c
+++ b/arch/um/os-Linux/registers.c
@@ -21,7 +21,7 @@ int save_registers(int pid, struct uml_pt_regs *regs)
 	return 0;
 }
 
-int restore_registers(int pid, struct uml_pt_regs *regs)
+int restore_pid_registers(int pid, struct uml_pt_regs *regs)
 {
 	int err;
 
@@ -36,7 +36,7 @@ int restore_registers(int pid, struct uml_pt_regs *regs)
 static unsigned long exec_regs[MAX_REG_NR];
 static unsigned long exec_fp_regs[FP_SIZE];
 
-int init_registers(int pid)
+int init_pid_registers(int pid)
 {
 	int err;
 
diff --git a/arch/um/os-Linux/sigio.c b/arch/um/os-Linux/sigio.c
index 6597ea1986ff..37d60e72cf26 100644
--- a/arch/um/os-Linux/sigio.c
+++ b/arch/um/os-Linux/sigio.c
@@ -3,6 +3,7 @@
  * Copyright (C) 2002 - 2008 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  */
 
+#include <linux/minmax.h>
 #include <unistd.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -50,7 +51,7 @@ static struct pollfds all_sigio_fds;
 
 static int write_sigio_thread(void *unused)
 {
-	struct pollfds *fds, tmp;
+	struct pollfds *fds;
 	struct pollfd *p;
 	int i, n, respond_fd;
 	char c;
@@ -77,9 +78,7 @@ static int write_sigio_thread(void *unused)
 					       "write_sigio_thread : "
 					       "read on socket failed, "
 					       "err = %d\n", errno);
-				tmp = current_poll;
-				current_poll = next_poll;
-				next_poll = tmp;
+				swap(current_poll, next_poll);
 				respond_fd = sigio_private[1];
 			}
 			else {
@@ -132,7 +131,7 @@ static void update_thread(void)
 	int n;
 	char c;
 
-	flags = set_signals_trace(0);
+	flags = um_set_signals_trace(0);
 	CATCH_EINTR(n = write(sigio_private[0], &c, sizeof(c)));
 	if (n != sizeof(c)) {
 		printk(UM_KERN_ERR "update_thread : write failed, err = %d\n",
@@ -147,7 +146,7 @@ static void update_thread(void)
 		goto fail;
 	}
 
-	set_signals_trace(flags);
+	um_set_signals_trace(flags);
 	return;
  fail:
 	/* Critical section start */
@@ -161,7 +160,7 @@ static void update_thread(void)
 	close(write_sigio_fds[0]);
 	close(write_sigio_fds[1]);
 	/* Critical section end */
-	set_signals_trace(flags);
+	um_set_signals_trace(flags);
 }
 
 int __add_sigio_fd(int fd)
diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
index 6cf098c23a39..24a403a70a02 100644
--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -94,7 +94,7 @@ void sig_handler(int sig, struct siginfo *si, mcontext_t *mc)
 
 	sig_handler_common(sig, si, mc);
 
-	set_signals_trace(enabled);
+	um_set_signals_trace(enabled);
 }
 
 static void timer_real_alarm_handler(mcontext_t *mc)
@@ -126,7 +126,7 @@ void timer_alarm_handler(int sig, struct siginfo *unused_si, mcontext_t *mc)
 
 	signals_active &= ~SIGALRM_MASK;
 
-	set_signals_trace(enabled);
+	um_set_signals_trace(enabled);
 }
 
 void deliver_alarm(void) {
@@ -348,7 +348,7 @@ void unblock_signals(void)
 	}
 }
 
-int set_signals(int enable)
+int um_set_signals(int enable)
 {
 	int ret;
 	if (signals_enabled == enable)
@@ -362,7 +362,7 @@ int set_signals(int enable)
 	return ret;
 }
 
-int set_signals_trace(int enable)
+int um_set_signals_trace(int enable)
 {
 	int ret;
 	if (signals_enabled == enable)
diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c
index 8a72c99994eb..e3ee4db58b40 100644
--- a/arch/um/os-Linux/start_up.c
+++ b/arch/um/os-Linux/start_up.c
@@ -368,7 +368,7 @@ void __init os_early_checks(void)
 	check_tmpexec();
 
 	pid = start_ptraced_child();
-	if (init_registers(pid))
+	if (init_pid_registers(pid))
 		fatal("Failed to initialize default registers");
 	stop_ptraced_child(pid, 1, 1);
 }