Merge tag 'uml-for-linus-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

Pull UML updates from Richard Weinberger:

 - Lots of cleanups, mostly from Benjamin Berg and Tiwei Bie

 - Removal of unused code

 - Fix for sparse warnings

 - Cleanup around stub_exe()

* tag 'uml-for-linus-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux: (68 commits)
  hostfs: Fix the NULL vs IS_ERR() bug for __filemap_get_folio()
  um: move thread info into task
  um: Always dump trace for specified task in show_stack
  um: vector: Do not use drvdata in release
  um: net: Do not use drvdata in release
  um: ubd: Do not use drvdata in release
  um: ubd: Initialize ubd's disk pointer in ubd_add
  um: virtio_uml: query the number of vqs if supported
  um: virtio_uml: fix call_fd IRQ allocation
  um: virtio_uml: send SET_MEM_TABLE message with the exact size
  um: remove broken double fault detection
  um: remove duplicate UM_NSEC_PER_SEC definition
  um: remove file sync for stub data
  um: always include kconfig.h and compiler-version.h
  um: set DONTDUMP and DONTFORK flags on KASAN shadow memory
  um: fix sparse warnings in signal code
  um: fix sparse warnings from regset refactor
  um: Remove double zero check
  um: fix stub exe build with CONFIG_GCOV
  um: Use os_set_pdeathsig helper in winch thread/process
  ...

1 files changed, 40 insertions, 35 deletions

diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index e8e8b54b3037..8037a967225d 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -65,9 +65,6 @@ struct cpuinfo_um boot_cpu_data = {
 
 EXPORT_SYMBOL(boot_cpu_data);
 
-union thread_union cpu0_irqstack
-	__section(".data..init_irqstack") =
-		{ .thread_info = INIT_THREAD_INFO(init_task) };
 
 /* Changed in setup_arch, which is called in early boot */
 static char host_info[(__NEW_UTS_LEN + 1) * 5];
@@ -131,7 +128,7 @@ static int have_root __initdata;
 static int have_console __initdata;
 
 /* Set in uml_mem_setup and modified in linux_main */
-long long physmem_size = 64 * 1024 * 1024;
+unsigned long long physmem_size = 64 * 1024 * 1024;
 EXPORT_SYMBOL(physmem_size);
 
 static const char *usage_string =
@@ -167,19 +164,6 @@ __uml_setup("root=", uml_root_setup,
 "        root=/dev/ubd5\n\n"
 );
 
-static int __init no_skas_debug_setup(char *line, int *add)
-{
-	os_warn("'debug' is not necessary to gdb UML in skas mode - run\n");
-	os_warn("'gdb linux'\n");
-
-	return 0;
-}
-
-__uml_setup("debug", no_skas_debug_setup,
-"debug\n"
-"    this flag is not needed to run gdb on UML in skas mode\n\n"
-);
-
 static int __init uml_console_setup(char *line, int *add)
 {
 	have_console = 1;
@@ -257,6 +241,8 @@ static struct notifier_block panic_exit_notifier = {
 
 void uml_finishsetup(void)
 {
+	cpu_tasks[0] = &init_task;
+
 	atomic_notifier_chain_register(&panic_notifier_list,
 				       &panic_exit_notifier);
 
@@ -302,7 +288,24 @@ static void parse_cache_line(char *line)
 	}
 }
 
-int __init linux_main(int argc, char **argv)
+static unsigned long get_top_address(char **envp)
+{
+	unsigned long top_addr = (unsigned long) &top_addr;
+	int i;
+
+	/* The earliest variable should be after the program name in ELF */
+	for (i = 0; envp[i]; i++) {
+		if ((unsigned long) envp[i] > top_addr)
+			top_addr = (unsigned long) envp[i];
+	}
+
+	top_addr &= ~(UM_KERN_PAGE_SIZE - 1);
+	top_addr += UM_KERN_PAGE_SIZE;
+
+	return top_addr;
+}
+
+int __init linux_main(int argc, char **argv, char **envp)
 {
 	unsigned long avail, diff;
 	unsigned long virtmem_size, max_physmem;
@@ -324,20 +327,23 @@ int __init linux_main(int argc, char **argv)
 	if (have_console == 0)
 		add_arg(DEFAULT_COMMAND_LINE_CONSOLE);
 
-	host_task_size = os_get_top_address();
-	/* reserve a few pages for the stubs (taking care of data alignment) */
-	/* align the data portion */
-	BUILD_BUG_ON(!is_power_of_2(STUB_DATA_PAGES));
-	stub_start = (host_task_size - 1) & ~(STUB_DATA_PAGES * PAGE_SIZE - 1);
+	host_task_size = get_top_address(envp);
+	/* reserve a few pages for the stubs */
+	stub_start = host_task_size - STUB_DATA_PAGES * PAGE_SIZE;
 	/* another page for the code portion */
 	stub_start -= PAGE_SIZE;
 	host_task_size = stub_start;
 
+	/* Limit TASK_SIZE to what is addressable by the page table */
+	task_size = host_task_size;
+	if (task_size > (unsigned long long) PTRS_PER_PGD * PGDIR_SIZE)
+		task_size = PTRS_PER_PGD * PGDIR_SIZE;
+
 	/*
 	 * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps
 	 * out
 	 */
-	task_size = host_task_size & PGDIR_MASK;
+	task_size = task_size & PGDIR_MASK;
 
 	/* OS sanity checks that need to happen before the kernel runs */
 	os_early_checks();
@@ -366,18 +372,15 @@ int __init linux_main(int argc, char **argv)
 
 	setup_machinename(init_utsname()->machine);
 
-	highmem = 0;
+	physmem_size = (physmem_size + PAGE_SIZE - 1) & PAGE_MASK;
 	iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
+
 	max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC;
 
-	/*
-	 * Zones have to begin on a 1 << MAX_PAGE_ORDER page boundary,
-	 * so this makes sure that's true for highmem
-	 */
-	max_physmem &= ~((1 << (PAGE_SHIFT + MAX_PAGE_ORDER)) - 1);
 	if (physmem_size + iomem_size > max_physmem) {
-		highmem = physmem_size + iomem_size - max_physmem;
-		physmem_size -= highmem;
+		physmem_size = max_physmem - iomem_size;
+		os_info("Physical memory size shrunk to %llu bytes\n",
+			physmem_size);
 	}
 
 	high_physmem = uml_physmem + physmem_size;
@@ -398,6 +401,8 @@ int __init linux_main(int argc, char **argv)
 		os_info("Kernel virtual memory size shrunk to %lu bytes\n",
 			virtmem_size);
 
+	arch_task_struct_size = sizeof(struct task_struct) + host_fp_size;
+
 	os_flush_stdout();
 
 	return start_uml();
@@ -412,9 +417,9 @@ void __init setup_arch(char **cmdline_p)
 {
 	u8 rng_seed[32];
 
-	stack_protections((unsigned long) &init_thread_info);
-	setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
-	mem_total_pages(physmem_size, iomem_size, highmem);
+	stack_protections((unsigned long) init_task.stack);
+	setup_physmem(uml_physmem, uml_reserved, physmem_size);
+	mem_total_pages(physmem_size, iomem_size);
 	uml_dtb_init();
 	read_initrd();