Merge tag 'uml-for-linux-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

Pull UML updates from Johannes Berg:
 "Apart from the usual small churn, we have

   - initial SMP support (only kernel)

   - major vDSO cleanups (and fixes for 32-bit)"

* tag 'uml-for-linux-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: (33 commits)
  um: Disable KASAN_INLINE when STATIC_LINK is selected
  um: Don't rename vmap to kernel_vmap
  um: drivers: virtio: use string choices helper
  um: Always set up AT_HWCAP and AT_PLATFORM
  x86/um: Remove FIXADDR_USER_START and FIXADDR_USE_END
  um: Remove __access_ok_vsyscall()
  um: Remove redundant range check from __access_ok_vsyscall()
  um: Remove fixaddr_user_init()
  x86/um: Drop gate area handling
  x86/um: Do not inherit vDSO from host
  um: Split out default elf_aux_hwcap
  x86/um: Move ELF_PLATFORM fallback to x86-specific code
  um: Split out default elf_aux_platform
  um: Avoid circular dependency on asm-offsets in pgtable.h
  um: Enable SMP support on x86
  asm-generic: percpu: Add assembly guard
  um: vdso: Remove getcpu support on x86
  um: Add initial SMP support
  um: Define timers on a per-CPU basis
  um: Determine sleep based on need_resched()
  ...

64 files changed, 972 insertions, 865 deletions

diff --git a/Documentation/features/core/generic-idle-thread/arch-support.txt b/Documentation/features/core/generic-idle-thread/arch-support.txt
index 0735cb5367b4..425442e31fa2 100644
--- a/Documentation/features/core/generic-idle-thread/arch-support.txt
+++ b/Documentation/features/core/generic-idle-thread/arch-support.txt
@@ -24,7 +24,7 @@
     |        s390: |  ok  |
     |          sh: |  ok  |
     |       sparc: |  ok  |
-    |          um: | TODO |
+    |          um: |  ok  |
     |         x86: |  ok  |
     |      xtensa: |  ok  |
     -----------------------
diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 49781bee7905..8415d39b0d43 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -5,6 +5,7 @@ menu "UML-specific options"
 config UML
 	bool
 	default y
+	select ARCH_DISABLE_KASAN_INLINE if STATIC_LINK
 	select ARCH_NEEDS_DEFER_KASAN if STATIC_LINK
 	select ARCH_WANTS_DYNAMIC_TASK_STRUCT
 	select ARCH_HAS_CACHE_LINE_SIZE
@@ -28,6 +29,7 @@ config UML
 	select OF_EARLY_FLATTREE if OF
 	select GENERIC_IRQ_SHOW
 	select GENERIC_CPU_DEVICES
+	select GENERIC_SMP_IDLE_THREAD
 	select HAVE_GCC_PLUGINS
 	select ARCH_SUPPORTS_LTO_CLANG
 	select ARCH_SUPPORTS_LTO_CLANG_THIN
@@ -81,10 +83,48 @@ config HZ
 	int
 	default 100
 
-config NR_CPUS
+config UML_SUBARCH_SUPPORTS_SMP
+	bool
+
+config SMP
+	bool "Symmetric multi-processing support"
+	default n
+	depends on UML_SUBARCH_SUPPORTS_SMP
+	help
+	  This option enables UML SMP support.
+
+	  With this enabled, users can tell UML to start multiple virtual
+	  processors. Each virtual processor is represented as a separate
+	  host thread.
+
+	  In UML, kthreads and normal threads (when running in kernel mode)
+	  can be scheduled and executed simultaneously on different virtual
+	  processors. However, the userspace code of normal threads still
+	  runs within their respective single-threaded stubs.
+
+	  That is, SMP support is available both within the kernel and
+	  across different processes, but remains limited within threads
+	  of the same process in userspace.
+
+config NR_CPUS_RANGE_BEGIN
 	int
-	range 1 1
-	default 1
+	default 1 if !SMP
+	default 2
+
+config NR_CPUS_RANGE_END
+	int
+	default 1 if !SMP
+	default 64
+
+config NR_CPUS_DEFAULT
+	int
+	default 1 if !SMP
+	default 2
+
+config NR_CPUS
+	int "Maximum number of CPUs" if SMP
+	range NR_CPUS_RANGE_BEGIN NR_CPUS_RANGE_END
+	default NR_CPUS_DEFAULT
 
 source "arch/$(HEADER_ARCH)/um/Kconfig"
 
@@ -200,12 +240,6 @@ config KERNEL_STACK_ORDER
 	  increase in the size of the state which needs to be saved when handling
 	  signals.
 
-config MMAPPER
-	tristate "iomem emulation driver"
-	help
-	  This driver allows a host file to be used as emulated IO memory inside
-	  UML.
-
 config PGTABLE_LEVELS
 	int
 	default 4 if 64BIT
@@ -260,6 +294,7 @@ source "arch/um/drivers/Kconfig"
 
 config ARCH_SUSPEND_POSSIBLE
 	def_bool y
+	depends on !SMP
 
 menu "Power management options"
 
diff --git a/arch/um/Makefile b/arch/um/Makefile
index 7be0143b5ba3..721b652ffb65 100644
--- a/arch/um/Makefile
+++ b/arch/um/Makefile
@@ -46,19 +46,17 @@ ARCH_INCLUDE	:= -I$(srctree)/$(SHARED_HEADERS)
 ARCH_INCLUDE	+= -I$(srctree)/$(HOST_DIR)/um/shared
 KBUILD_CPPFLAGS += -I$(srctree)/$(HOST_DIR)/um
 
-# -Dvmap=kernel_vmap prevents anything from referencing the libpcap.o symbol so
-# named - it's a common symbol in libpcap, so we get a binary which crashes.
-#
-# Same things for in6addr_loopback and mktime - found in libc. For these two we
-# only get link-time error, luckily.
+# -Dstrrchr=kernel_strrchr (as well as the various in6addr symbols) prevents
+#  anything from referencing
+# libc symbols with the same name, which can cause a linker error.
 #
 # -Dlongjmp=kernel_longjmp prevents anything from referencing the libpthread.a
 # embedded copy of longjmp, same thing for setjmp.
 #
-# These apply to USER_CFLAGS to.
+# These apply to USER_CFLAGS too.
 
 KBUILD_CFLAGS += $(CFLAGS) $(CFLAGS-y) -D__arch_um__ \
-	$(ARCH_INCLUDE) $(MODE_INCLUDE) -Dvmap=kernel_vmap	\
+	$(ARCH_INCLUDE) $(MODE_INCLUDE)	\
 	-Dlongjmp=kernel_longjmp -Dsetjmp=kernel_setjmp \
 	-Din6addr_loopback=kernel_in6addr_loopback \
 	-Din6addr_any=kernel_in6addr_any -Dstrrchr=kernel_strrchr \
diff --git a/arch/um/drivers/Makefile b/arch/um/drivers/Makefile
index 6bf8cbf71d3c..36dc57840084 100644
--- a/arch/um/drivers/Makefile
+++ b/arch/um/drivers/Makefile
@@ -29,7 +29,6 @@ obj-$(CONFIG_STDERR_CONSOLE) += stderr_console.o
 
 obj-$(CONFIG_UML_NET_VECTOR) += vector.o
 obj-$(CONFIG_MCONSOLE) += mconsole.o
-obj-$(CONFIG_MMAPPER) += mmapper_kern.o 
 obj-$(CONFIG_BLK_DEV_UBD) += ubd.o 
 obj-$(CONFIG_UML_SOUND) += hostaudio.o
 obj-$(CONFIG_NULL_CHAN) += null.o 
diff --git a/arch/um/drivers/mmapper_kern.c b/arch/um/drivers/mmapper_kern.c
deleted file mode 100644
index 807cd3358740..000000000000
--- a/arch/um/drivers/mmapper_kern.c
+++ /dev/null
@@ -1,135 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * arch/um/drivers/mmapper_kern.c
- *
- * BRIEF MODULE DESCRIPTION
- *
- * Copyright (C) 2000 RidgeRun, Inc.
- * Author: RidgeRun, Inc.
- *         Greg Lonnon glonnon@ridgerun.com or info@ridgerun.com
- *
- */
-
-#include <linux/stddef.h>
-#include <linux/types.h>
-#include <linux/fs.h>
-#include <linux/init.h>
-#include <linux/miscdevice.h>
-#include <linux/module.h>
-#include <linux/mm.h>
-
-#include <linux/uaccess.h>
-#include <mem_user.h>
-
-/* These are set in mmapper_init, which is called at boot time */
-static unsigned long mmapper_size;
-static unsigned long p_buf;
-static char *v_buf;
-
-static ssize_t mmapper_read(struct file *file, char __user *buf, size_t count,
-			    loff_t *ppos)
-{
-	return simple_read_from_buffer(buf, count, ppos, v_buf, mmapper_size);
-}
-
-static ssize_t mmapper_write(struct file *file, const char __user *buf,
-			     size_t count, loff_t *ppos)
-{
-	if (*ppos > mmapper_size)
-		return -EINVAL;
-
-	return simple_write_to_buffer(v_buf, mmapper_size, ppos, buf, count);
-}
-
-static long mmapper_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-{
-	return -ENOIOCTLCMD;
-}
-
-static int mmapper_mmap(struct file *file, struct vm_area_struct *vma)
-{
-	int ret = -EINVAL;
-	int size;
-
-	if (vma->vm_pgoff != 0)
-		goto out;
-
-	size = vma->vm_end - vma->vm_start;
-	if (size > mmapper_size)
-		return -EFAULT;
-
-	/*
-	 * XXX A comment above remap_pfn_range says it should only be
-	 * called when the mm semaphore is held
-	 */
-	if (remap_pfn_range(vma, vma->vm_start, p_buf >> PAGE_SHIFT, size,
-			    vma->vm_page_prot))
-		goto out;
-	ret = 0;
-out:
-	return ret;
-}
-
-static int mmapper_open(struct inode *inode, struct file *file)
-{
-	return 0;
-}
-
-static int mmapper_release(struct inode *inode, struct file *file)
-{
-	return 0;
-}
-
-static const struct file_operations mmapper_fops = {
-	.owner		= THIS_MODULE,
-	.read		= mmapper_read,
-	.write		= mmapper_write,
-	.unlocked_ioctl	= mmapper_ioctl,
-	.mmap		= mmapper_mmap,
-	.open		= mmapper_open,
-	.release	= mmapper_release,
-	.llseek		= default_llseek,
-};
-
-/*
- * No locking needed - only used (and modified) by below initcall and exitcall.
- */
-static struct miscdevice mmapper_dev = {
-	.minor		= MISC_DYNAMIC_MINOR,
-	.name		= "mmapper",
-	.fops		= &mmapper_fops
-};
-
-static int __init mmapper_init(void)
-{
-	int err;
-
-	printk(KERN_INFO "Mapper v0.1\n");
-
-	v_buf = (char *) find_iomem("mmapper", &mmapper_size);
-	if (mmapper_size == 0) {
-		printk(KERN_ERR "mmapper_init - find_iomem failed\n");
-		return -ENODEV;
-	}
-	p_buf = __pa(v_buf);
-
-	err = misc_register(&mmapper_dev);
-	if (err) {
-		printk(KERN_ERR "mmapper - misc_register failed, err = %d\n",
-		       err);
-		return err;
-	}
-	return 0;
-}
-
-static void __exit mmapper_exit(void)
-{
-	misc_deregister(&mmapper_dev);
-}
-
-module_init(mmapper_init);
-module_exit(mmapper_exit);
-
-MODULE_AUTHOR("Greg Lonnon <glonnon@ridgerun.com>");
-MODULE_DESCRIPTION("DSPLinux simulator mmapper driver");
-MODULE_LICENSE("GPL");
diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c
index de7867ae220d..6cf1152a1a4e 100644
--- a/arch/um/drivers/virtio_uml.c
+++ b/arch/um/drivers/virtio_uml.c
@@ -24,6 +24,7 @@
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
+#include <linux/string_choices.h>
 #include <linux/virtio.h>
 #include <linux/virtio_config.h>
 #include <linux/virtio_ring.h>
@@ -1151,8 +1152,7 @@ void virtio_uml_set_no_vq_suspend(struct virtio_device *vdev,
 		return;
 
 	vu_dev->no_vq_suspend = no_vq_suspend;
-	dev_info(&vdev->dev, "%sabled VQ suspend\n",
-		 no_vq_suspend ? "dis" : "en");
+	dev_info(&vdev->dev, "%s VQ suspend\n", str_disabled_enabled(no_vq_suspend));
 }
 
 static void vu_of_conn_broken(struct work_struct *wk)
diff --git a/arch/um/include/asm/current.h b/arch/um/include/asm/current.h
index 8accc6d6f502..159a29b3d4cc 100644
--- a/arch/um/include/asm/current.h
+++ b/arch/um/include/asm/current.h
@@ -7,15 +7,16 @@
 
 #ifndef __ASSEMBLER__
 
+#include <shared/smp.h>
+
 struct task_struct;
 extern struct task_struct *cpu_tasks[NR_CPUS];
 
 static __always_inline struct task_struct *get_current(void)
 {
-	return cpu_tasks[0];
+	return cpu_tasks[uml_curr_cpu()];
 }
 
-
 #define current get_current()
 
 #endif /* __ASSEMBLER__ */
diff --git a/arch/um/include/asm/hardirq.h b/arch/um/include/asm/hardirq.h
index 52e2c36267a9..8de71752a9b8 100644
--- a/arch/um/include/asm/hardirq.h
+++ b/arch/um/include/asm/hardirq.h
@@ -2,8 +2,30 @@
 #ifndef __ASM_UM_HARDIRQ_H
 #define __ASM_UM_HARDIRQ_H
 
-#include <asm-generic/hardirq.h>
+#include <linux/cache.h>
+#include <linux/threads.h>
 
 #define __ARCH_IRQ_EXIT_IRQS_DISABLED 1
 
+typedef struct {
+	unsigned int __softirq_pending;
+#if IS_ENABLED(CONFIG_SMP)
+	unsigned int irq_resched_count;
+	unsigned int irq_call_count;
+#endif
+} ____cacheline_aligned irq_cpustat_t;
+
+DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
+
+#define __ARCH_IRQ_STAT
+
+#define inc_irq_stat(member)	this_cpu_inc(irq_stat.member)
+
+#include <linux/irq.h>
+
+static inline void ack_bad_irq(unsigned int irq)
+{
+	pr_crit("unexpected IRQ trap at vector %02x\n", irq);
+}
+
 #endif /* __ASM_UM_HARDIRQ_H */
diff --git a/arch/um/include/asm/irqflags.h b/arch/um/include/asm/irqflags.h
index 1e69ef5bc35e..31e49e0894c5 100644
--- a/arch/um/include/asm/irqflags.h
+++ b/arch/um/include/asm/irqflags.h
@@ -2,7 +2,7 @@
 #ifndef __UM_IRQFLAGS_H
 #define __UM_IRQFLAGS_H
 
-extern int signals_enabled;
+int um_get_signals(void);
 int um_set_signals(int enable);
 void block_signals(void);
 void unblock_signals(void);
@@ -10,7 +10,7 @@ void unblock_signals(void);
 #define arch_local_save_flags arch_local_save_flags
 static inline unsigned long arch_local_save_flags(void)
 {
-	return signals_enabled;
+	return um_get_signals();
 }
 
 #define arch_local_irq_restore arch_local_irq_restore
diff --git a/arch/um/include/asm/kasan.h b/arch/um/include/asm/kasan.h
index b54a4e937fd1..81bcdc0f962e 100644
--- a/arch/um/include/asm/kasan.h
+++ b/arch/um/include/asm/kasan.h
@@ -24,10 +24,6 @@
 
 #ifdef CONFIG_KASAN
 void kasan_init(void);
-
-#if defined(CONFIG_STATIC_LINK) && defined(CONFIG_KASAN_INLINE)
-#error UML does not work in KASAN_INLINE mode with STATIC_LINK enabled!
-#endif
 #else
 static inline void kasan_init(void) { }
 #endif /* CONFIG_KASAN */
diff --git a/arch/um/include/asm/mmu.h b/arch/um/include/asm/mmu.h
index 4d0e4239f3cc..07d48738b402 100644
--- a/arch/um/include/asm/mmu.h
+++ b/arch/um/include/asm/mmu.h
@@ -7,16 +7,26 @@
 #define __ARCH_UM_MMU_H
 
 #include "linux/types.h"
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
 #include <mm_id.h>
 
 typedef struct mm_context {
 	struct mm_id id;
+	struct mutex turnstile;
 
 	struct list_head list;
 
 	/* Address range in need of a TLB sync */
+	spinlock_t sync_tlb_lock;
 	unsigned long sync_tlb_range_from;
 	unsigned long sync_tlb_range_to;
 } mm_context_t;
 
+#define INIT_MM_CONTEXT(mm)						\
+	.context = {							\
+		.turnstile = __MUTEX_INITIALIZER(mm.context.turnstile),	\
+		.sync_tlb_lock = __SPIN_LOCK_INITIALIZER(mm.context.sync_tlb_lock), \
+	}
+
 #endif
diff --git a/arch/um/include/asm/page.h b/arch/um/include/asm/page.h
index 6f54254aaf44..2d363460d896 100644
--- a/arch/um/include/asm/page.h
+++ b/arch/um/include/asm/page.h
@@ -96,8 +96,4 @@ extern unsigned long uml_physmem;
 
 #endif	/* __ASSEMBLER__ */
 
-#ifdef CONFIG_X86_32
-#define __HAVE_ARCH_GATE_AREA 1
-#endif
-
 #endif	/* __UM_PAGE_H */
diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h
index 24fdea6f88c3..3b42b0f45bf6 100644
--- a/arch/um/include/asm/pgtable.h
+++ b/arch/um/include/asm/pgtable.h
@@ -45,10 +45,12 @@ extern unsigned long *empty_zero_page;
  * area for the same reason. ;)
  */
 
-extern unsigned long end_iomem;
+#ifndef COMPILE_OFFSETS
+#include <as-layout.h> /* for high_physmem */
+#endif
 
 #define VMALLOC_OFFSET	(__va_space)
-#define VMALLOC_START ((end_iomem + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1))
+#define VMALLOC_START	((high_physmem + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1))
 #define VMALLOC_END	(TASK_SIZE-2*PAGE_SIZE)
 #define MODULES_VADDR	VMALLOC_START
 #define MODULES_END	VMALLOC_END
@@ -225,6 +227,8 @@ static inline void set_pte(pte_t *pteptr, pte_t pteval)
 static inline void um_tlb_mark_sync(struct mm_struct *mm, unsigned long start,
 				    unsigned long end)
 {
+	guard(spinlock_irqsave)(&mm->context.sync_tlb_lock);
+
 	if (!mm->context.sync_tlb_range_to) {
 		mm->context.sync_tlb_range_from = start;
 		mm->context.sync_tlb_range_to = end;
diff --git a/arch/um/include/asm/smp.h b/arch/um/include/asm/smp.h
index a8cc1d46ddcb..be1743a6ff3c 100644
--- a/arch/um/include/asm/smp.h
+++ b/arch/um/include/asm/smp.h
@@ -2,6 +2,19 @@
 #ifndef __UM_SMP_H
 #define __UM_SMP_H
 
-#define hard_smp_processor_id()		0
+#if IS_ENABLED(CONFIG_SMP)
+
+#include <linux/cpumask.h>
+#include <shared/smp.h>
+
+#define raw_smp_processor_id() uml_curr_cpu()
+
+void arch_smp_send_reschedule(int cpu);
+
+void arch_send_call_function_single_ipi(int cpu);
+
+void arch_send_call_function_ipi_mask(const struct cpumask *mask);
+
+#endif /* CONFIG_SMP */
 
 #endif
diff --git a/arch/um/include/asm/uaccess.h b/arch/um/include/asm/uaccess.h
index 1c6e0ae41b0c..0df9ea4abda8 100644
--- a/arch/um/include/asm/uaccess.h
+++ b/arch/um/include/asm/uaccess.h
@@ -15,11 +15,6 @@
 	(((unsigned long) (addr) < TASK_SIZE) && \
 	 (((unsigned long) (addr) + (size)) < TASK_SIZE))
 
-#define __access_ok_vsyscall(addr, size) \
-	  (((unsigned long) (addr) >= FIXADDR_USER_START) && \
-	  ((unsigned long) (addr) + (size) <= FIXADDR_USER_END) && \
-	  ((unsigned long) (addr) + (size) >= (unsigned long)(addr)))
-
 #define __addr_range_nowrap(addr, size) \
 	((unsigned long) (addr) <= ((unsigned long) (addr) + (size)))
 
@@ -40,9 +35,7 @@ static inline int __access_ok(const void __user *ptr, unsigned long size);
 static inline int __access_ok(const void __user *ptr, unsigned long size)
 {
 	unsigned long addr = (unsigned long)ptr;
-	return __addr_range_nowrap(addr, size) &&
-		(__under_task_size(addr, size) ||
-		 __access_ok_vsyscall(addr, size));
+	return __addr_range_nowrap(addr, size) && __under_task_size(addr, size);
 }
 
 #define __get_kernel_nofault(dst, src, type, err_label)			\
diff --git a/arch/um/include/linux/smp-internal.h b/arch/um/include/linux/smp-internal.h
new file mode 100644
index 000000000000..1dbcbc23f9c9
--- /dev/null
+++ b/arch/um/include/linux/smp-internal.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UM_SMP_INTERNAL_H
+#define __UM_SMP_INTERNAL_H
+
+#if IS_ENABLED(CONFIG_SMP)
+
+void prefill_possible_map(void);
+
+#else /* !CONFIG_SMP */
+
+static inline void prefill_possible_map(void) { }
+
+#endif /* CONFIG_SMP */
+
+extern char cpu_irqstacks[NR_CPUS][THREAD_SIZE] __aligned(THREAD_SIZE);
+
+#endif /* __UM_SMP_INTERNAL_H */
diff --git a/arch/um/include/linux/time-internal.h b/arch/um/include/linux/time-internal.h
index 138908b999d7..c274eb5ad55e 100644
--- a/