Merging upstream version 6.10.3.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

38 files changed, 202 insertions, 145 deletions

diff --git a/arch/um/Makefile b/arch/um/Makefile
index 34957dcb88..00b63bac5e 100644
--- a/arch/um/Makefile
+++ b/arch/um/Makefile
@@ -20,7 +20,7 @@ endif
 ARCH_DIR := arch/um
 # We require bash because the vmlinux link and loader script cpp use bash
 # features.
-SHELL := /bin/bash
+SHELL := bash
 
 MODE_INCLUDE	+= -I$(srctree)/$(ARCH_DIR)/include/shared/skas
 
diff --git a/arch/um/drivers/pcap_kern.c b/arch/um/drivers/pcap_kern.c
index 25ee2c97ca..d9bf95d786 100644
--- a/arch/um/drivers/pcap_kern.c
+++ b/arch/um/drivers/pcap_kern.c
@@ -15,7 +15,7 @@ struct pcap_init {
 	char *filter;
 };
 
-void pcap_init_kern(struct net_device *dev, void *data)
+static void pcap_init_kern(struct net_device *dev, void *data)
 {
 	struct uml_net_private *pri;
 	struct pcap_data *ppri;
@@ -50,7 +50,7 @@ static const struct net_kern_info pcap_kern_info = {
 	.write			= pcap_write,
 };
 
-int pcap_setup(char *str, char **mac_out, void *data)
+static int pcap_setup(char *str, char **mac_out, void *data)
 {
 	struct pcap_init *init = data;
 	char *remain, *host_if = NULL, *options[2] = { NULL, NULL };
diff --git a/arch/um/drivers/rtc_kern.c b/arch/um/drivers/rtc_kern.c
index 97ceb205cf..3a1582219c 100644
--- a/arch/um/drivers/rtc_kern.c
+++ b/arch/um/drivers/rtc_kern.c
@@ -168,16 +168,15 @@ cleanup:
 	return err;
 }
 
-static int uml_rtc_remove(struct platform_device *pdev)
+static void uml_rtc_remove(struct platform_device *pdev)
 {
 	device_init_wakeup(&pdev->dev, 0);
 	uml_rtc_cleanup();
-	return 0;
 }
 
 static struct platform_driver uml_rtc_driver = {
 	.probe = uml_rtc_probe,
-	.remove = uml_rtc_remove,
+	.remove_new = uml_rtc_remove,
 	.driver = {
 		.name = "uml-rtc",
 	},
diff --git a/arch/um/drivers/slirp_user.c b/arch/um/drivers/slirp_user.c
index 8f633e2e5f..97228aa080 100644
--- a/arch/um/drivers/slirp_user.c
+++ b/arch/um/drivers/slirp_user.c
@@ -49,7 +49,7 @@ static int slirp_tramp(char **argv, int fd)
 static int slirp_open(void *data)
 {
 	struct slirp_data *pri = data;
-	int fds[2], pid, err;
+	int fds[2], err;
 
 	err = os_pipe(fds, 1, 1);
 	if (err)
@@ -60,7 +60,6 @@ static int slirp_open(void *data)
 		printk(UM_KERN_ERR "slirp_tramp failed - errno = %d\n", -err);
 		goto out;
 	}
-	pid = err;
 
 	pri->slave = fds[1];
 	pri->slip.pos = 0;
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index ef805eaa9e..093c87879d 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -447,43 +447,31 @@ static int bulk_req_safe_read(
 	return n;
 }
 
-/* Called without dev->lock held, and only in interrupt context. */
-static void ubd_handler(void)
+static void ubd_end_request(struct io_thread_req *io_req)
 {
-	int n;
-	int count;
-
-	while(1){
-		n = bulk_req_safe_read(
-			thread_fd,
-			irq_req_buffer,
-			&irq_remainder,
-			&irq_remainder_size,
-			UBD_REQ_BUFFER_SIZE
-		);
-		if (n < 0) {
-			if(n == -EAGAIN)
-				break;
-			printk(KERN_ERR "spurious interrupt in ubd_handler, "
-			       "err = %d\n", -n);
-			return;
-		}
-		for (count = 0; count < n/sizeof(struct io_thread_req *); count++) {
-			struct io_thread_req *io_req = (*irq_req_buffer)[count];
-
-			if ((io_req->error == BLK_STS_NOTSUPP) && (req_op(io_req->req) == REQ_OP_DISCARD)) {
-				blk_queue_max_discard_sectors(io_req->req->q, 0);
-				blk_queue_max_write_zeroes_sectors(io_req->req->q, 0);
-			}
-			blk_mq_end_request(io_req->req, io_req->error);
-			kfree(io_req);
-		}
+	if (io_req->error == BLK_STS_NOTSUPP) {
+		if (req_op(io_req->req) == REQ_OP_DISCARD)
+			blk_queue_max_discard_sectors(io_req->req->q, 0);
+		else if (req_op(io_req->req) == REQ_OP_WRITE_ZEROES)
+			blk_queue_max_write_zeroes_sectors(io_req->req->q, 0);
 	}
+	blk_mq_end_request(io_req->req, io_req->error);
+	kfree(io_req);
 }
 
 static irqreturn_t ubd_intr(int irq, void *dev)
 {
-	ubd_handler();
+	int len, i;
+
+	while ((len = bulk_req_safe_read(thread_fd, irq_req_buffer,
+			&irq_remainder, &irq_remainder_size,
+			UBD_REQ_BUFFER_SIZE)) >= 0) {
+		for (i = 0; i < len / sizeof(struct io_thread_req *); i++)
+			ubd_end_request((*irq_req_buffer)[i]);
+	}
+
+	if (len < 0 && len != -EAGAIN)
+		pr_err("spurious interrupt in %s, err = %d\n", __func__, len);
 	return IRQ_HANDLED;
 }
 
diff --git a/arch/um/drivers/ubd_user.c b/arch/um/drivers/ubd_user.c
index a1afe414ce..b4f8b8e605 100644
--- a/arch/um/drivers/ubd_user.c
+++ b/arch/um/drivers/ubd_user.c
@@ -23,7 +23,7 @@
 #include <os.h>
 #include <poll.h>
 
-struct pollfd kernel_pollfd;
+static struct pollfd kernel_pollfd;
 
 int start_io_thread(unsigned long sp, int *fd_out)
 {
diff --git a/arch/um/drivers/vector_kern.c b/arch/um/drivers/vector_kern.c
index 63e5f108a6..4279793b11 100644
--- a/arch/um/drivers/vector_kern.c
+++ b/arch/um/drivers/vector_kern.c
@@ -712,11 +712,9 @@ static struct vector_device *find_device(int n)
 static int vector_parse(char *str, int *index_out, char **str_out,
 			char **error_out)
 {
-	int n, len, err;
+	int n, err;
 	char *start = str;
 
-	len = strlen(str);
-
 	while ((*str != ':') && (strlen(str) > 1))
 		str++;
 	if (*str != ':') {
diff --git a/arch/um/drivers/virt-pci.c b/arch/um/drivers/virt-pci.c
index 97a37c0629..7cb503469b 100644
--- a/arch/um/drivers/virt-pci.c
+++ b/arch/um/drivers/virt-pci.c
@@ -752,7 +752,6 @@ MODULE_DEVICE_TABLE(virtio, id_table);
 
 static struct virtio_driver um_pci_virtio_driver = {
 	.driver.name = "virtio-pci",
-	.driver.owner = THIS_MODULE,
 	.id_table = id_table,
 	.probe = um_pci_virtio_probe,
 	.remove = um_pci_virtio_remove,
diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c
index 8adca2000e..77faa2cf3a 100644
--- a/arch/um/drivers/virtio_uml.c
+++ b/arch/um/drivers/virtio_uml.c
@@ -1241,12 +1241,11 @@ error_free:
 	return rc;
 }
 
-static int virtio_uml_remove(struct platform_device *pdev)
+static void virtio_uml_remove(struct platform_device *pdev)
 {
 	struct virtio_uml_device *vu_dev = platform_get_drvdata(pdev);
 
 	unregister_virtio_device(&vu_dev->vdev);
-	return 0;
 }
 
 /* Command line device list */
@@ -1445,7 +1444,7 @@ static int virtio_uml_resume(struct platform_device *pdev)
 
 static struct platform_driver virtio_uml_driver = {
 	.probe = virtio_uml_probe,
-	.remove = virtio_uml_remove,
+	.remove_new = virtio_uml_remove,
 	.driver = {
 		.name = "virtio-uml",
 		.of_match_table = virtio_uml_match,
diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild
index b2d834a29f..6fe3477929 100644
--- a/arch/um/include/asm/Kbuild
+++ b/arch/um/include/asm/Kbuild
@@ -8,7 +8,6 @@ generic-y += dma-mapping.h
 generic-y += emergency-restart.h
 generic-y += exec.h
 generic-y += extable.h
-generic-y += fb.h
 generic-y += ftrace.h
 generic-y += hw_irq.h
 generic-y += irq_regs.h
@@ -28,3 +27,4 @@ generic-y += trace_clock.h
 generic-y += kprobes.h
 generic-y += mm_hooks.h
 generic-y += vga.h
+generic-y += video.h
diff --git a/arch/um/include/asm/cpufeature.h b/arch/um/include/asm/cpufeature.h
index 66fe06db87..1eb8b834fb 100644
--- a/arch/um/include/asm/cpufeature.h
+++ b/arch/um/include/asm/cpufeature.h
@@ -38,8 +38,7 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
 
 #define this_cpu_has(bit)						\
 	(__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :	\
-	 x86_this_cpu_test_bit(bit,					\
-		(unsigned long __percpu *)&cpu_info.x86_capability))
+	 x86_this_cpu_test_bit(bit, cpu_info.x86_capability))
 
 /*
  * This macro is for detection of features which need kernel
diff --git a/arch/um/include/asm/ptrace-generic.h b/arch/um/include/asm/ptrace-generic.h
index adf91ef553..4696f24d14 100644
--- a/arch/um/include/asm/ptrace-generic.h
+++ b/arch/um/include/asm/ptrace-generic.h
@@ -36,6 +36,9 @@ extern long subarch_ptrace(struct task_struct *child, long request,
 extern unsigned long getreg(struct task_struct *child, int regno);
 extern int putreg(struct task_struct *child, int regno, unsigned long value);
 
+extern int poke_user(struct task_struct *child, long addr, long data);
+extern int peek_user(struct task_struct *child, long addr, long data);
+
 extern int arch_set_tls(struct task_struct *new, unsigned long tls);
 extern void clear_flushed_tls(struct task_struct *task);
 extern int syscall_trace_enter(struct pt_regs *regs);
diff --git a/arch/um/include/shared/as-layout.h b/arch/um/include/shared/as-layout.h
index 9ec3015bc5..c22f46a757 100644
--- a/arch/um/include/shared/as-layout.h
+++ b/arch/um/include/shared/as-layout.h
@@ -31,7 +31,6 @@
 #include <sysdep/ptrace.h>
 
 struct cpu_task {
-	int pid;
 	void *task;
 };
 
diff --git a/arch/um/include/shared/kern_util.h b/arch/um/include/shared/kern_util.h
index af8cdfc758..95521b1f5b 100644
--- a/arch/um/include/shared/kern_util.h
+++ b/arch/um/include/shared/kern_util.h
@@ -41,6 +41,7 @@ extern void uml_pm_wake(void);
 
 extern int start_uml(void);
 extern void paging_init(void);
+extern int parse_iomem(char *str, int *add);
 
 extern void uml_cleanup(void);
 extern void do_uml_exitcalls(void);
diff --git a/arch/um/include/shared/um_malloc.h b/arch/um/include/shared/um_malloc.h
index 13da93284c..815dd03e87 100644
--- a/arch/um/include/shared/um_malloc.h
+++ b/arch/um/include/shared/um_malloc.h
@@ -11,8 +11,9 @@
 extern void *uml_kmalloc(int size, int flags);
 extern void kfree(const void *ptr);
 
-extern void *vmalloc(unsigned long size);
-extern void vfree(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/kernel/Makefile b/arch/um/kernel/Makefile
index 811188be95..f8567b933f 100644
--- a/arch/um/kernel/Makefile
+++ b/arch/um/kernel/Makefile
@@ -47,7 +47,7 @@ $(obj)/config.c: $(src)/config.c.in $(obj)/config.tmp FORCE
 	$(call if_changed,quote2)
 
 quiet_cmd_mkcapflags = MKCAP   $@
-      cmd_mkcapflags = $(CONFIG_SHELL) $(srctree)/$(src)/../../x86/kernel/cpu/mkcapflags.sh $@ $^
+      cmd_mkcapflags = $(CONFIG_SHELL) $(src)/../../x86/kernel/cpu/mkcapflags.sh $@ $^
 
 cpufeature = $(src)/../../x86/include/asm/cpufeatures.h
 vmxfeature = $(src)/../../x86/include/asm/vmxfeatures.h
diff --git a/arch/um/kernel/kmsg_dump.c b/arch/um/kernel/kmsg_dump.c
index 427dd5a61a..4382cf02a6 100644
--- a/arch/um/kernel/kmsg_dump.c
+++ b/arch/um/kernel/kmsg_dump.c
@@ -57,7 +57,7 @@ static struct kmsg_dumper kmsg_dumper = {
 	.dump = kmsg_dumper_stdout
 };
 
-int __init kmsg_dumper_stdout_init(void)
+static int __init kmsg_dumper_stdout_init(void)
 {
 	return kmsg_dump_register(&kmsg_dumper);
 }
diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index 38d5a71a57..ca91accd64 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -12,12 +12,14 @@
 #include <linux/slab.h>
 #include <asm/fixmap.h>
 #include <asm/page.h>
+#include <asm/pgalloc.h>
 #include <as-layout.h>
 #include <init.h>
 #include <kern.h>
 #include <kern_util.h>
 #include <mem_user.h>
 #include <os.h>
+#include <um_malloc.h>
 #include <linux/sched/task.h>
 
 #ifdef CONFIG_KASAN
diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c
index 91485119ae..fb2adfb499 100644
--- a/arch/um/kernel/physmem.c
+++ b/arch/um/kernel/physmem.c
@@ -12,6 +12,7 @@
 #include <as-layout.h>
 #include <init.h>
 #include <kern.h>
+#include <kern_util.h>
 #include <mem_user.h>
 #include <os.h>
 
@@ -161,8 +162,6 @@ __uml_setup("mem=", uml_mem_setup,
 "	Example: mem=64M\n\n"
 );
 
-extern int __init parse_iomem(char *str, int *add);
-
 __uml_setup("iomem=", parse_iomem,
 "iomem=<name>,<file>\n"
 "    Configure <file> as an IO memory region named <name>.\n\n"
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index ab95648e93..d2134802f6 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -15,6 +15,7 @@
 #include <linux/proc_fs.h>
 #include <linux/ptrace.h>
 #include <linux/random.h>
+#include <linux/cpu.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
@@ -26,6 +27,8 @@
 #include <linux/resume_user_mode.h>
 #include <asm/current.h>
 #include <asm/mmu_context.h>
+#include <asm/switch_to.h>
+#include <asm/exec.h>
 #include <linux/uaccess.h>
 #include <as-layout.h>
 #include <kern_util.h>
@@ -40,24 +43,7 @@
  * cares about its entry, so it's OK if another processor is modifying its
  * entry.
  */
-struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { -1, NULL } };
-
-static inline int external_pid(void)
-{
-	/* FIXME: Need to look up userspace_pid by cpu */
-	return userspace_pid[0];
-}
-
-int pid_to_processor_id(int pid)
-{
-	int i;
-
-	for (i = 0; i < ncpus; i++) {
-		if (cpu_tasks[i].pid == pid)
-			return i;
-	}
-	return -1;
-}
+struct cpu_task cpu_tasks[NR_CPUS] = { [0 ... NR_CPUS - 1] = { NULL } };
 
 void free_stack(unsigned long stack, int order)
 {
@@ -78,13 +64,10 @@ unsigned long alloc_stack(int order, int atomic)
 
 static inline void set_current(struct task_struct *task)
 {
-	cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task)
-		{ external_pid(), task });
+	cpu_tasks[task_thread_info(task)->cpu] = ((struct cpu_task) { task });
 }
 
-extern void arch_switch_to(struct task_struct *to);
-
-void *__switch_to(struct task_struct *from, struct task_struct *to)
+struct task_struct *__switch_to(struct task_struct *from, struct task_struct *to)
 {
 	to->thread.prev_sched = from;
 	set_current(to);
@@ -119,7 +102,7 @@ int get_current_pid(void)
  */
 void new_thread_handler(void)
 {
-	int (*fn)(void *), n;
+	int (*fn)(void *);
 	void *arg;
 
 	if (current->thread.prev_sched != NULL)
@@ -132,12 +115,12 @@ void new_thread_handler(void)
 	/*
 	 * callback returns only if the kernel thread execs a process
 	 */
-	n = fn(arg);
+	fn(arg);
 	userspace(&current->thread.regs.regs, current_thread_info()->aux_fp_regs);
 }
 
 /* Called magically, see new_thread_handler above */
-void fork_handler(void)
+static void fork_handler(void)
 {
 	force_flush_all();
 
@@ -216,7 +199,6 @@ void um_idle_sleep(void)
 
 void arch_cpu_idle(void)
 {
-	cpu_tasks[current_thread_info()->cpu].pid = os_getpid();
 	um_idle_sleep();
 }
 
@@ -250,32 +232,22 @@ char *uml_strdup(const char *string)
 }
 EXPORT_SYMBOL(uml_strdup);
 
-int copy_to_user_proc(void __user *to, void *from, int size)
-{
-	return copy_to_user(to, from, size);
-}
-
 int copy_from_user_proc(void *to, void __user *from, int size)
 {
 	return copy_from_user(to, from, size);
 }
 
-int clear_user_proc(void __user *buf, int size)
-{
-	return clear_user(buf, size);
-}
-
 static atomic_t using_sysemu = ATOMIC_INIT(0);
 int sysemu_supported;
 
-void set_using_sysemu(int value)
+static void set_using_sysemu(int value)
 {
 	if (value > sysemu_supported)
 		return;
 	atomic_set(&using_sysemu, value);
 }
 
-int get_using_sysemu(void)
+static int get_using_sysemu(void)
 {
 	return atomic_read(&using_sysemu);
 }
@@ -313,7 +285,7 @@ static const struct proc_ops sysemu_proc_ops = {
 	.proc_write	= sysemu_proc_write,
 };
 
-int __init make_proc_sysemu(void)
+static int __init make_proc_sysemu(void)
 {
 	struct proc_dir_entry *ent;
 	if (!sysemu_supported)
diff --git a/arch/um/kernel/ptrace.c b/arch/um/kernel/ptrace.c
index 6600a27827..2124624b78 100644
--- a/arch/um/kernel/ptrace.c
+++ b/arch/um/kernel/ptrace.c
@@ -35,9 +35,6 @@ void ptrace_disable(struct task_struct *child)
 	user_disable_single_step(child);
 }
 
-extern int peek_user(struct task_struct * child, long addr, long data);
-extern int poke_user(struct task_struct * child, long addr, long data);
-
 long arch_ptrace(struct task_struct *child, long request,
 		 unsigned long addr, unsigned long data)
 {
diff --git a/arch/um/kernel/reboot.c b/arch/um/kernel/reboot.c
index 48c0610d50..25840eee10 100644
--- a/arch/um/kernel/reboot.c
+++ b/arch/um/kernel/reboot.c
@@ -9,6 +9,7 @@
 #include <linux/spinlock.h>
 #include <linux/slab.h>
 #include <linux/oom.h>
+#include <linux/reboot.h>
 #include <kern_util.h>
 #include <os.h>
 #include <skas.h>
diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c
index 656fe16c9b..aeed1c2aaf 100644
--- a/arch/um/kernel/skas/mmu.c
+++ b/arch/um/kernel/skas/mmu.c
@@ -10,6 +10,7 @@
 
 #include <asm/pgalloc.h>
 #include <asm/sections.h>
+#include <asm/mmu_context.h>
 #include <as-layout.h>
 #include <os.h>
 #include <skas.h>
diff --git a/arch/um/kernel/skas/process.c b/arch/um/kernel/skas/process.c
index f2ac134c97..99a5cbb360 100644
--- a/arch/um/kernel/skas/process.c
+++ b/arch/um/kernel/skas/process.c
@@ -12,17 +12,14 @@
 #include <kern.h>
 #include <os.h>
 #include <skas.h>
+#include <kern_util.h>
 
 extern void start_kernel(void);
 
 static int __init start_kernel_proc(void *unused)
 {
-	int pid;
-
 	block_signals_trace();
-	pid = os_getpid();
 
-	cpu_tasks[0].pid = pid;
 	cpu_tasks[0].task = current;
 
 	start_kernel();
diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c
index 3e270da6b6..5b5fd8f68d 100644
--- a/arch/um/kernel/time.c
+++ b/arch/um/kernel/time.c
@@ -19,6 +19,7 @@
 #include <asm/param.h>
 #include <kern_util.h>
 #include <os.h>
+#include <linux/delay.h>
 #include <linux/time-internal.h>
 #include <linux/um_timetravel.h>
 #include <shared/init.h>
@@ -319,7 +320,7 @@ void time_travel_add_event_rel(struct time_travel_event *e,
 	time_travel_add_event(e, time_travel_time + delay_ns);
 }
 
-void time_travel_periodic_timer(struct time_travel_event *e)
+static void time_travel_periodic_timer(struct time_travel_event *e)
 {
 	time_travel_add_event(&time_travel_timer_event,
 			      time_travel_time + time_travel_timer_interval);
@@ -812,7 +813,7 @@ unsigned long calibrate_delay_is_known(void)
 	return 0;
 }
 
-int setup_time_travel(char *str)
+static int setup_time_travel(char *str)
 {
 	if (strcmp(str, "=inf-cpu") == 0) {
 		time_travel_mode = TT_MODE_INFCPU;
@@ -862,7 +863,7 @@ __uml_help(setup_time_travel,
 "devices using it, assuming the device has the right capabilities.\n"
 "The optional ID is a 64-bit integer that's sent to the central scheduler.\n");
 
-int setup_time_travel_start(char *str)
+static int setup_time_travel_start(char *str)
 {
 	int err;
 
@@ -874,9 +875,9 @@ int setup_time_travel_start(char *str)
 	return 1;
 }
 
-__setup("time-travel-start", setup_time_travel_start);
+__setup("time-travel-start=", setup_time_travel_start);
 __uml_help(setup_time_travel_start,
-"time-travel-start=<seconds>\n"
+"time-travel-start=<nanoseconds>\n"
 "Configure the UML instance's wall clock to start at this value rather than\n"
 "the host's wall clock at the time of UML boot.\n");
 #endif
diff --git a/arch/um/kernel/tlb.c b/arch/um/kernel/tlb.c
index 7d050ab0f7..8784f03fa4 100644
--- a/arch/um/kernel/tlb.c
+++ b/arch/um/kernel/tlb.c
@@ -8,6 +8,7 @@
 #include <linux/sched/signal.h>
 
 #include <asm/tlbflush.h>
+#include <asm/mmu_context.h>
 #include <as-layout.h>
 #include <mem_user.h>
 #include <os.h>
@@ -576,12 +577,6 @@ void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 }
 EXPORT_SYMBOL(flush_tlb_range);
 
-void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
-			unsigned long end)
-{
-	fix_range(mm, start, end, 0);
-}
-
 void flush_tlb_mm(struct mm_struct *mm)
 {
 	struct vm_area_struct *vma;
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 7a9820797e..e95f805e50 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -23,6 +23,7 @@
 #include <asm/cpufeature.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
+#include <asm/text-patching.h>
 #include <as-layout.h>
 #include <arch.h>
 #include <init.h>
diff --git a/arch/um/kernel/um_arch.h b/arch/um/kernel/um_arch.h
index 1e07fb7ee3..46e731ab9d 100644
--- a/arch/um/kernel/um_arch.h
+++ b/arch/um/kernel/um_arch.h
@@ -11,4 +11,6 @@ extern void __init uml_dtb_init(void);
 static inline void uml_dtb_init(void) { }
 #endif
 
+extern int __init read_initrd(void);
+
 #endif
diff --git a/arch/um/os-Linux/drivers/ethertap_kern.c b/arch/um/os-Linux/drivers/ethertap_kern.c
index 3182e759d8..5e5ee40680 100644
--- a/arch/um/os-Linux/drivers/ethertap_kern.c
+++ b/arch/um/os-Linux/drivers/ethertap_kern.c
@@ -63,7 +63,7 @@ const struct net_kern_info ethertap_kern_info = {
 	.write 			= etap_write,
 };
 
-int ethertap_setup(char *str, char **mac_out, void *data)
+static int ethertap_setup(char *str, char **mac_out, void *data)
 {
 	struct ethertap_init *init = data;
 
diff --git a/arch/um/os-Linux/drivers/tuntap_kern.c b/arch/um/os-Linux/drivers/tuntap_kern.c
index adcb6717be..ff022d9cf0 100644
--- a/arch/um/os-Linux/drivers/tuntap_kern.c
+++ b/arch/um/os-Linux/drivers/tuntap_kern.c
@@ -53,7 +53,7 @@ const struct net_kern_info tuntap_kern_info = {
 	.write 			= tuntap_write,
 };
 
-int tuntap_setup(char *str, char **mac_out, void *data)
+static int tuntap_setup(char *str, char **mac_out, void *data)
 {
 	struct tuntap_init *init = data;
 
diff --git a/arch/um/os-Linux/elf_aux.c b/arch/um/os-Linux/elf_aux.c
index 344ac403fb..0a0f91cf4d 100644
--- a/arch/um/os-Linux/elf_aux.c
+++ b/arch/um/os-Linux/elf_aux.c
@@ -13,6 +13,7 @@
 #include <init.h>
 #include <elf_user.h>
 #include <mem_user.h>
+#include "internal.h"
 
 typedef Elf32_auxv_t elf_auxv_t;
 
diff --git a/arch/um/os-Linux/internal.h b/arch/um/os-Linux/internal.h
new file mode 100644
index 0000000000..317fca190c
--- /dev/null
+++ b/arch/um/os-Linux/internal.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UM_OS_LINUX_INTERNAL_H
+#define __UM_OS_LINUX_INTERNAL_H
+
+/*
+ * elf_aux.c
+ */
+void scan_elf_aux(char **envp);
+
+/*
+ * mem.c
+ */
+void check_tmpexec(void);
+
+/*
+ * skas/process.c
+ */
+void wait_stub_done(int pid);
+
+#endif /* __UM_OS_LINUX_INTERNAL_H */
diff --git a/arch/um/os-Linux/main.c b/arch/um/os-Linux/main.c
index c8a42ecbd7..f98ff79cdb 100644
--- a/arch/um/os-Linux/main.c
+++ b/arch/um/os-Linux/main.c
@@ -16,6 +16,7 @@
 #include <kern_util.h>
 #include <os.h>
 #include <um_malloc.h>
+#include "internal.h"
 
 #define PGD_BOUND (4 * 1024 * 1024)
 #define STACKSIZE (8 * 1024 * 1024)
@@ -102,8 +103,6 @@ static void setup_env_path(void)
 	}
 }
 
-extern void scan_elf_aux( char **envp);
-
 int __init main(int argc, char **argv, char **envp)
 {
 	char **new_argv;
@@ -184,6 +183,11 @@ int __init main(int argc, char **argv, char **envp)
 
 extern void *__real_malloc(int);
 
+/* workaround for -Wmissing-prototypes warnings */
+void *__wrap_malloc(int size);
+void *__wrap_calloc(int n, int size);
+void __wrap_free(void *ptr);
+
 void *__wrap_malloc(int size)
 {
 	void *ret;
diff --git a/arch/um/os-Linux/mem.c b/arch/um/os-Linux/mem.c
index c6c9495b14..cf44d386f2 100644
--- a/arch/um/os-Linux/mem.c
+++ b/arch/um/os-Linux/mem.c
@@ -17,6 +17,7 @@
 #include <init.h>
 #include <kern_util.h>
 #include <os.h>
+#include "internal.h"
 
 /*
  * kasan_map_memory - maps memory from @start with a size of @len.
diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
index 24a403a70a..b11ed66c8b 100644
--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -8,6 +8,7 @@
 
 #include <stdlib.h>
 #include <stdarg.h>
+#include <stdbool.h>
 #include <errno.h>
 #include <signal.h>
 #include <string.h>
@@ -65,25 +66,36 @@ static void sig_handler_common(int sig, struct siginfo *si, mcontext_t *mc)
 
 int signals_enabled;
 #ifdef UML_CONFIG_UML_TIME_TRAVEL_SUPPORT
-static int signals_blocked;
-#else
-#define signals_blocked 0
+static int signals_blocked, signals_blocked_pending;
 #endif
 static unsigned int signals_pending;
 static unsigned int signals_active = 0;
 
-void sig_handler(int sig, struct siginfo *si, mcontext_t *mc)
+static void sig_handler(int sig, struct siginfo *si, mcontext_t *mc)
 {
 	int enabled = signals_enabled;
 
-	if ((signals_blocked || !enabled) && (sig == SIGIO)) {
+#ifdef UML_CONFIG_UML_TIME_TRAVEL_SUPPORT
+	if ((signals_blocked ||
+	     __atomic_load_n(&signals_blocked_pending, __ATOMIC_SEQ_CST)) &&
+	    (sig == SIGIO)) {
+		/* increment so unblock will do another round */
+		__atomic_add_fetch(&signals_blocked_pending, 1,
+				   __ATOMIC_SEQ_CST);
+		return;
+	}
+#endif
+
+	if (!enabled && (sig == SIGIO)) {
 		/*
 		 * In TT_MODE_EXTERNAL, need to still call time-travel
-		 * handlers unless signals are also blocked for the
-		 * external time message processing. This will mark
-		 * signals_pending by itself (only if necessary.)
+		 * handlers. This will mark signals_pending by itself
+		 * (only if necessary.)
+		 * Note we won't get here if signals are hard-blocked
+		 * (which is handled above), in that case the hard-
+		 * unblock will handle things.
 		 */
-		if (!signals_blocked && time_travel_mode == TT_MODE_EXTERNAL)
+		if (time_travel_mode == TT_MODE_EXTERNAL)
 			sigio_run_timetravel_handlers();
 		else
 			signals_pending |= SIGIO_MASK;
@@ -108,7 +120,7 @@ static void timer_real_alarm_handler(mcontext_t *mc)
 	timer_handler(SIGALRM, NULL, &regs);
 }
 
-void timer_alarm_handler(int sig, struct siginfo *unused_si, mcontext_t *mc)
+static void timer_alarm_handler(int sig, struct siginfo *unused_si, mcontext_t *mc)
 {
 	int enabled;
 
@@ -380,33 +392,99 @@ int um_set_signals_trace(int enable)
 #ifdef UML_CONFIG_UML_TIME_TRAVEL_SUPPORT
 void mark_sigio_pending(void)
 {
+	/*
+	 * It would seem that this should be atomic so
+	 * it isn't a read-modify-write with a signal
+	 * that could happen in the middle, losing the
+	 * value set by the signal.
+	 *
+	 * However, this function is only called when in
+	 * time-travel=ext simulation mode, in which case
+	 * the only signal ever pending is SIGIO, which
+	 * is blocked while this can be called, and the
+	 * timer signal (SIGALRM) cannot happen.
+	 */
 	signals_pending |= SIGIO_MASK;
 }
 
 void block_signals_hard(void)
 {
-	if (signals_blocked)
-		return;
-	signals_blocked = 1;
+	signals_blocked++;
 	barrier();
 }
 
 void unblock_signals_hard(void)
 {
+	static bool unblocking;
+
 	if (!signals_blocked)
+		panic("unblocking signals while not blocked");
+
+	if (--signals_blocked)
 		return;
-	/* Must be set to 0 before we check the pending bits etc. */
-	signals_blocked = 0;
+	/*
+	 * Must be set to 0 before we check pending so the
+	 * SIGIO handler will run as normal unless we're still
+	 * going to process signals_blocked_pending.
+	 */
 	barrier();
 
-	if (signals_pending && signals_enabled) {
-		/* this is a bit inefficient, but that's not really important */
-		block_signals();
-		unblock_signals();
-	} else if (signals_pending & SIGIO_MASK) {
-		/* we need to run time-travel handlers even if not enabled */
-		sigio_run_timetravel_handlers();
+	/*
+	 * Note that block_signals_hard()/unblock_signals_hard() can be called
+	 * within the unblock_signals()/sigio_run_timetravel_handlers() below.
+	 * This would still be prone to race conditions since it's actually a
+	 * call _within_ e.g. vu_req_read_message(), where we observed this
+	 * issue, which loops. Thus, if the inner call handles the recorded
+	 * pending signals, we can get out of the inner call with the real
+	 * signal hander no longer blocked, and still have a race. Thus don't
+	 * handle unblocking in the inner call, if it happens, but only in
+	 * the outermost call - 'unblocking' serves as an ownership for the
+	 * signals_blocked_pending decrement.
+	 */
+	if (unblocking)
+		return;
+	unblocking = true;
+
+	while (__atomic_load_n(&signals_blocked_pending, __ATOMIC_SEQ_CST)) {
+		if (signals_enabled) {
+			/* signals are enabled so we can touch this */
+			signals_pending |= SIGIO_MASK;
+			/*
+			 * this is a bit inefficient, but that's
+			 * not really important
+			 */
+			block_signals();
+			unblock_signals();
+		} else {
+			/*
+			 * we need to run time-travel handlers even
+			 * if not enabled
+			 */
+			sigio_run_timetravel_handlers();
+		}
+
+		/*
+		 * The decrement of signals_blocked_pending must be atomic so
+		 * that the signal handler will either happen before or after
+		 * the decrement, not during a read-modify-write:
+		 *  - If it happens before, it can increment it and we'll
+		 *    decrement it and do another round in the loop.
+		 *  - If it happens after it'll see 0 for both signals_blocked
+		 *    and signals_blocked_pending and thus run the handler as
+		 *    usual (subject to signals_enabled, but that's unrelated.)
+		 *
+		 * Note that a call to unblock_signals_hard() within the calls
+		 * to unblock_signals() or sigio_run_timetravel_handlers() above
+		 * will do nothing due to the 'unblocking' state, so this cannot
+		 * underflow as the only one decrementing will be the outermost
+		 * one.
+		 */
+		if (__atomic_sub_fetch(&signals_blocked_pending, 1,
+				       __ATOMIC_SEQ_CST) < 0)
+			panic("signals_blocked_pending underflow");
 	}
+
+	unblocking = false;
 }
 #endif
 
diff --git a/arch/um/os-Linux/skas/mem.c b/arch/um/os-Linux/skas/mem.c
index 953fb10f3f..1f9c1bffc3 100644
--- a/arch/um/os-Linux/skas/mem.c
+++ b/arch/um/os-Linux/skas/mem.c
@@ -17,11 +17,10 @@
 #include <skas.h>
 #include <sysdep/ptrace.h>
 #include <sysdep/stub.h>
+#include "../internal.h"
 
 extern char batch_syscall_stub[], __syscall_stub_start[];
 
-extern void wait_stub_done(int pid);
-
 static inline unsigned long *check_init_stack(struct mm_id * mm_idp,
 					      unsigned long *stack)
 {
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 1f5c3f2523..41a288dcfc 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -23,6 +23,7 @@
 #include <skas.h>
 #include <sysdep/stub.h>
 #include <linux/threads.h>
+#include "../internal.h"
 
 int is_skas_winch(int pid, int fd, void *data)
 {
diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c
index 8b0e98ab84..89ad9f4f86 100644
--- a/arch/um/os-Linux/start_up.c
+++ b/arch/um/os-Linux/start_up.c
@@ -20,10 +20,12 @@
 #include <asm/unistd.h>
 #include <init.h>
 #include <os.h>
+#include <kern_util.h>
 #include <mem_user.h>
 #include <ptrace_user.h>
 #include <registers.h>
 #include <skas.h>
+#include "internal.h"
 
 static void ptrace_child(void)
 {
@@ -221,8 +223,6 @@ static void __init check_ptrace(void)
 	check_sysemu();
 }
 
-extern void check_tmpexec(void);
-
 static void __init check_coredump_limit(void)
 {
 	struct rlimit lim;