Merge tag 'uml-for-linux-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

Pull UML updates from Johannes Berg:

 - proper nofault accesses and read-only rodata

 - hostfs fix for host inode number reuse

 - fixes for host errno handling

 - various cleanups/small fixes

* tag 'uml-for-linux-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux:
  um: Rewrite the sigio workaround based on epoll and tgkill
  um: Prohibit the VM_CLONE flag in run_helper_thread()
  um: Switch to the pthread-based helper in sigio workaround
  um: ubd: Switch to the pthread-based helper
  um: Add pthread-based helper support
  um: x86: clean up elf specific definitions
  um: Store full CSGSFS and SS register from mcontext
  um: virt-pci: Refactor virtio_pcidev into its own module
  um: work around sched_yield not yielding in time-travel mode
  um/locking: Remove semicolon from "lock" prefix
  um: Update min_low_pfn to match changes in uml_reserved
  um: use str_yes_no() to remove hardcoded "yes" and "no"
  um: hostfs: avoid issues on inode number reuse by host
  um: Allocate vdso page pointer statically
  um: remove copy_from_kernel_nofault_allowed
  um: mark rodata read-only and implement _nofault accesses
  um: Pass the correct Rust target and options with gcc

Author: torvalds

arch/um/Kconfig

@@ -12,6 +12,7 @@ config UML
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_STRNCPY_FROM_USER
 	select ARCH_HAS_STRNLEN_USER
+	select ARCH_HAS_STRICT_KERNEL_RWX
 	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_ARCH_KASAN if X86_64
 	select HAVE_ARCH_KASAN_VMALLOC if HAVE_ARCH_KASAN

arch/um/drivers/Kconfig

@@ -345,16 +345,20 @@ config UML_RTC
 	  by providing a fake RTC clock that causes a wakeup at the right
 	  time.
 
-config UML_PCI_OVER_VIRTIO
-	bool "Enable PCI over VIRTIO device simulation"
-	# in theory, just VIRTIO is enough, but that causes recursion
-	depends on VIRTIO_UML
+config UML_PCI
+	bool
 	select FORCE_PCI
 	select UML_IOMEM_EMULATION
 	select UML_DMA_EMULATION
 	select PCI_MSI
 	select PCI_LOCKLESS_CONFIG
 
+config UML_PCI_OVER_VIRTIO
+	bool "Enable PCI over VIRTIO device simulation"
+	# in theory, just VIRTIO is enough, but that causes recursion
+	depends on VIRTIO_UML
+	select UML_PCI
+
 config UML_PCI_OVER_VIRTIO_DEVICE_ID
 	int "set the virtio device ID for PCI emulation"
 	default -1

arch/um/drivers/Makefile

@@ -60,7 +60,8 @@ obj-$(CONFIG_BLK_DEV_COW_COMMON) += cow_user.o
 obj-$(CONFIG_UML_RANDOM) += random.o
 obj-$(CONFIG_VIRTIO_UML) += virtio_uml.o
 obj-$(CONFIG_UML_RTC) += rtc.o
-obj-$(CONFIG_UML_PCI_OVER_VIRTIO) += virt-pci.o
+obj-$(CONFIG_UML_PCI) += virt-pci.o
+obj-$(CONFIG_UML_PCI_OVER_VIRTIO) += virtio_pcidev.o
 
 # pcap_user.o must be added explicitly.
 USER_OBJS := fd.o null.o pty.o tty.o xterm.o slip_common.o vde_user.o vector_user.o

arch/um/drivers/random.c

@@ -79,7 +79,7 @@ static int __init rng_init (void)
 	if (err < 0)
 		goto err_out_cleanup_hw;
 
-	sigio_broken(random_fd);
+	sigio_broken();
 	hwrng.name = RNG_MODULE_NAME;
 	hwrng.read = rng_dev_read;
 

arch/um/drivers/rtc_user.c

@@ -39,7 +39,7 @@ int uml_rtc_start(bool timetravel)
 		}
 
 		/* apparently timerfd won't send SIGIO, use workaround */
-		sigio_broken(uml_rtc_irq_fds[0]);
+		sigio_broken();
 		err = add_sigio_fd(uml_rtc_irq_fds[0]);
 		if (err < 0) {
 			close(uml_rtc_irq_fds[0]);

arch/um/drivers/ubd.h

@@ -7,8 +7,10 @@
 #ifndef __UM_UBD_USER_H
 #define __UM_UBD_USER_H
 
-extern int start_io_thread(unsigned long sp, int *fds_out);
-extern int io_thread(void *arg);
+#include <os.h>
+
+int start_io_thread(struct os_helper_thread **td_out, int *fd_out);
+void *io_thread(void *arg);
 extern int kernel_fd;
 
 extern int ubd_read_poll(int timeout);

arch/um/drivers/ubd_kern.c

@@ -474,12 +474,12 @@ static irqreturn_t ubd_intr(int irq, void *dev)
 }
 
 /* Only changed by ubd_init, which is an initcall. */
-static int io_pid = -1;
+static struct os_helper_thread *io_td;
 
 static void kill_io_thread(void)
 {
-	if(io_pid != -1)
-		os_kill_process(io_pid, 1);
+	if (io_td)
+		os_kill_helper_thread(io_td);
 }
 
 __uml_exitcall(kill_io_thread);
@@ -1104,8 +1104,8 @@ static int __init ubd_init(void)
 
 late_initcall(ubd_init);
 
-static int __init ubd_driver_init(void){
-	unsigned long stack;
+static int __init ubd_driver_init(void)
+{
 	int err;
 
 	/* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/
@@ -1114,13 +1114,11 @@ static int __init ubd_driver_init(void){
 		/* Letting ubd=sync be like using ubd#s= instead of ubd#= is
 		 * enough. So use anyway the io thread. */
 	}
-	stack = alloc_stack(0, 0);
-	io_pid = start_io_thread(stack + PAGE_SIZE, &thread_fd);
-	if(io_pid < 0){
+	err = start_io_thread(&io_td, &thread_fd);
+	if (err < 0) {
 		printk(KERN_ERR
 		       "ubd : Failed to start I/O thread (errno = %d) - "
-		       "falling back to synchronous I/O\n", -io_pid);
-		io_pid = -1;
+		       "falling back to synchronous I/O\n", -err);
 		return 0;
 	}
 	err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr,
@@ -1496,12 +1494,11 @@ int kernel_fd = -1;
 /* Only changed by the io thread. XXX: currently unused. */
 static int io_count;
 
-int io_thread(void *arg)
+void *io_thread(void *arg)
 {
 	int n, count, written, res;
 
-	os_set_pdeathsig();
-	os_fix_helper_signals();
+	os_fix_helper_thread_signals();
 
 	while(1){
 		n = bulk_req_safe_read(
@@ -1543,5 +1540,5 @@ int io_thread(void *arg)
 		} while (written < n);
 	}
 
-	return 0;
+	return NULL;
 }

arch/um/drivers/ubd_user.c

@@ -25,9 +25,9 @@
 
 static struct pollfd kernel_pollfd;
 
-int start_io_thread(unsigned long sp, int *fd_out)
+int start_io_thread(struct os_helper_thread **td_out, int *fd_out)
 {
-	int pid, fds[2], err;
+	int fds[2], err;
 
 	err = os_pipe(fds, 1, 1);
 	if(err < 0){
@@ -47,14 +47,14 @@ int start_io_thread(unsigned long sp, int *fd_out)
 		goto out_close;
 	}
 
-	pid = clone(io_thread, (void *) sp, CLONE_FILES | CLONE_VM, NULL);
-	if(pid < 0){
-		err = -errno;
-		printk("start_io_thread - clone failed : errno = %d\n", errno);
+	err = os_run_helper_thread(td_out, io_thread, NULL);
+	if (err < 0) {
+		printk("%s - failed to run helper thread, err = %d\n",
+		       __func__, -err);
 		goto out_close;
 	}
 
-	return(pid);
+	return 0;
 
  out_close:
 	os_close_file(fds[0]);