Merge tag 'uml-for-linus-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

Pull UML updates from Richard Weinberger:

 - Clang coverage support

 - Many cleanups from Benjamin Berg

 - Various minor fixes

* tag 'uml-for-linus-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux:
  um: Mark 32bit syscall helpers as clobbering memory
  um: Remove unused register save/restore functions
  um: Rely on PTRACE_SETREGSET to set FS/GS base registers
  Documentation: kunit: Add clang UML coverage example
  arch: um: Add Clang coverage support
  um: time-travel: fix time corruption
  um: net: Fix return type of uml_net_start_xmit()
  um: Always inline stub functions
  um: Do not use printk in userspace trampoline
  um: Reap winch thread if it fails
  um: Do not use printk in SIGWINCH helper thread
  um: Don't use vfprintf() for os_info()
  um: Make errors to stop ptraced child fatal during startup
  um: Drop NULL check from start_userspace
  um: Drop support for hosts without SYSEMU_SINGLESTEP support
  um: document arch_futex_atomic_op_inuser
  um: mmu: remove stub_pages
  um: Fix naming clash between UML and scheduler
  um: virt-pci: fix platform map offset

Author: torvalds

Documentation/dev-tools/kunit/running_tips.rst

@@ -139,6 +139,17 @@ If your installed version of gcc doesn't work, you can tweak the steps:
 	$ ./tools/testing/kunit/kunit.py run --make_options=CC=/usr/bin/gcc-6
 	$ lcov -t "my_kunit_tests" -o coverage.info -c -d .kunit/ --gcov-tool=/usr/bin/gcov-6
 
+Alternatively, LLVM-based toolchains can also be used:
+
+.. code-block:: bash
+
+	# Build with LLVM and append coverage options to the current config
+	$ ./tools/testing/kunit/kunit.py run --make_options LLVM=1 --kunitconfig=.kunit/ --kunitconfig=tools/testing/kunit/configs/coverage_uml.config
+	$ llvm-profdata merge -sparse default.profraw -o default.profdata
+	$ llvm-cov export --format=lcov .kunit/vmlinux -instr-profile default.profdata > coverage.info
+	# The coverage.info file is in lcov-compatible format and it can be used to e.g. generate HTML report
+	$ genhtml -o /tmp/coverage_html coverage.info
+
 
 Running tests manually
 ======================

arch/um/Makefile-skas

@@ -4,7 +4,12 @@
 #
 
 GPROF_OPT += -pg
+
+ifdef CONFIG_CC_IS_CLANG
+GCOV_OPT += -fprofile-instr-generate -fcoverage-mapping
+else
 GCOV_OPT += -fprofile-arcs -ftest-coverage
+endif
 
 CFLAGS-$(CONFIG_GCOV) += $(GCOV_OPT)
 CFLAGS-$(CONFIG_GPROF) += $(GPROF_OPT)

arch/um/drivers/chan_user.c

@@ -141,7 +141,7 @@ struct winch_data {
 	int pipe_fd;
 };
 
-static int winch_thread(void *arg)
+static __noreturn int winch_thread(void *arg)
 {
 	struct winch_data *data = arg;
 	sigset_t sigs;
@@ -153,8 +153,8 @@ static int winch_thread(void *arg)
 	pipe_fd = data->pipe_fd;
 	count = write(pipe_fd, &c, sizeof(c));
 	if (count != sizeof(c))
-		printk(UM_KERN_ERR "winch_thread : failed to write "
-		       "synchronization byte, err = %d\n", -count);
+		os_info("winch_thread : failed to write synchronization byte, err = %d\n",
+			-count);
 
 	/*
 	 * We are not using SIG_IGN on purpose, so don't fix it as I thought to
@@ -166,29 +166,29 @@ static int winch_thread(void *arg)
 	sigfillset(&sigs);
 	/* Block all signals possible. */
 	if (sigprocmask(SIG_SETMASK, &sigs, NULL) < 0) {
-		printk(UM_KERN_ERR "winch_thread : sigprocmask failed, "
-		       "errno = %d\n", errno);
-		exit(1);
+		os_info("winch_thread : sigprocmask failed, errno = %d\n",
+			errno);
+		goto wait_kill;
 	}
 	/* In sigsuspend(), block anything else than SIGWINCH. */
 	sigdelset(&sigs, SIGWINCH);
 
 	if (setsid() < 0) {
-		printk(UM_KERN_ERR "winch_thread : setsid failed, errno = %d\n",
+		os_info("winch_thread : setsid failed, errno = %d\n",
 		       errno);
-		exit(1);
+		goto wait_kill;
 	}
 
 	if (ioctl(pty_fd, TIOCSCTTY, 0) < 0) {
-		printk(UM_KERN_ERR "winch_thread : TIOCSCTTY failed on "
-		       "fd %d err = %d\n", pty_fd, errno);
-		exit(1);
+		os_info("winch_thread : TIOCSCTTY failed on "
+			"fd %d err = %d\n", pty_fd, errno);
+		goto wait_kill;
 	}
 
 	if (tcsetpgrp(pty_fd, os_getpid()) < 0) {
-		printk(UM_KERN_ERR "winch_thread : tcsetpgrp failed on "
-		       "fd %d err = %d\n", pty_fd, errno);
-		exit(1);
+		os_info("winch_thread : tcsetpgrp failed on fd %d err = %d\n",
+			pty_fd, errno);
+		goto wait_kill;
 	}
 
 	/*
@@ -199,8 +199,8 @@ static int winch_thread(void *arg)
 	 */
 	count = read(pipe_fd, &c, sizeof(c));
 	if (count != sizeof(c))
-		printk(UM_KERN_ERR "winch_thread : failed to read "
-		       "synchronization byte, err = %d\n", errno);
+		os_info("winch_thread : failed to read synchronization byte, err = %d\n",
+			errno);
 
 	while(1) {
 		/*
@@ -211,9 +211,15 @@ static int winch_thread(void *arg)
 
 		count = write(pipe_fd, &c, sizeof(c));
 		if (count != sizeof(c))
-			printk(UM_KERN_ERR "winch_thread : write failed, "
-			       "err = %d\n", errno);
+			os_info("winch_thread : write failed, err = %d\n",
+				errno);
 	}
+
+wait_kill:
+	c = 2;
+	count = write(pipe_fd, &c, sizeof(c));
+	while (1)
+		pause();
 }
 
 static int winch_tramp(int fd, struct tty_port *port, int *fd_out,

arch/um/drivers/line.c

@@ -629,15 +629,18 @@ static irqreturn_t winch_interrupt(int irq, void *data)
 
 	if (fd != -1) {
 		err = generic_read(fd, &c, NULL);
-		if (err < 0) {
+		/* A read of 2 means the winch thread failed and has warned */
+		if (err < 0 || (err == 1 && c == 2)) {
 			if (err != -EAGAIN) {
 				winch->fd = -1;
 				list_del(&winch->list);
 				os_close_file(fd);
-				printk(KERN_ERR "winch_interrupt : "
-				       "read failed, errno = %d\n", -err);
-				printk(KERN_ERR "fd %d is losing SIGWINCH "
-				       "support\n", winch->tty_fd);
+				if (err < 0) {
+					printk(KERN_ERR "winch_interrupt : read failed, errno = %d\n",
+					       -err);
+					printk(KERN_ERR "fd %d is losing SIGWINCH support\n",
+					       winch->tty_fd);
+				}
 				INIT_WORK(&winch->work, __free_winch);
 				schedule_work(&winch->work);
 				return IRQ_HANDLED;

arch/um/drivers/net_kern.c

@@ -204,7 +204,7 @@ static int uml_net_close(struct net_device *dev)
 	return 0;
 }
 
-static int uml_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t uml_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct uml_net_private *lp = netdev_priv(dev);
 	unsigned long flags;

arch/um/drivers/virt-pci.c

@@ -971,7 +971,7 @@ static long um_pci_map_platform(unsigned long offset, size_t size,
 	*ops = &um_pci_device_bar_ops;
 	*priv = &um_pci_platform_device->resptr[0];
 
-	return 0;
+	return offset;
 }
 
 static const struct logic_iomem_region_ops um_pci_platform_ops = {

arch/um/include/asm/mmu.h

@@ -12,7 +12,6 @@
 typedef struct mm_context {
 	struct mm_id id;
 	struct uml_arch_mm_context arch;
-	struct page *stub_pages[2];
 } mm_context_t;
 
 extern void __switch_mm(struct mm_id * mm_idp);

arch/um/include/asm/processor-generic.h

@@ -22,7 +22,6 @@ struct mm_struct;
 struct thread_struct {
 	struct pt_regs regs;
 	struct pt_regs *segv_regs;
-	int singlestep_syscall;
 	void *fault_addr;
 	jmp_buf *fault_catcher;
 	struct task_struct *prev_sched;

arch/um/include/shared/kern_util.h

@@ -34,7 +34,6 @@ extern int handle_page_fault(unsigned long address, unsigned long ip,
 
 extern unsigned int do_IRQ(int irq, struct uml_pt_regs *regs);
 extern void initial_thread_cb(void (*proc)(void *), void *arg);
-extern int is_syscall(unsigned long addr);
 
 extern void timer_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs);
 
@@ -50,15 +49,15 @@ extern void do_uml_exitcalls(void);
  * Are we disallowed to sleep? Used to choose between GFP_KERNEL and
  * GFP_ATOMIC.
  */
-extern int __cant_sleep(void);
+extern int __uml_cant_sleep(void);
 extern int get_current_pid(void);
 extern int copy_from_user_proc(void *to, void *from, int size);
 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 int singlestepping(void *t);
+extern int singlestepping(void);
 
 extern void segv_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs);
 extern void bus_handler(int sig, struct siginfo *si, struct uml_pt_regs *regs);

arch/um/include/shared/os.h

@@ -323,9 +323,6 @@ extern void sigio_broken(int fd);
 extern int __add_sigio_fd(int fd);
 extern int __ignore_sigio_fd(int fd);
 
-/* prctl.c */
-extern int os_arch_prctl(int pid, int option, unsigned long *arg2);
-
 /* tty.c */
 extern int get_pty(void);