Merge tag 'uml-for-linus-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux

Pull UML updates from Richard Weinberger:

 - hostfs: Convert to writepages

 - many cleanups: removal of dead macros, missing __init

* tag 'uml-for-linus-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux:
  um: Remove unused asm/archparam.h header
  um: Include missing headers in asm/pgtable.h
  hostfs: Convert to writepages
  um: rtc: use RTC time when calculating the alarm
  um: Remove unused user_context function
  um: Remove unused THREAD_NAME_LEN macro
  um: Remove unused PGD_BOUND macro
  um: Mark setup_env_path as __init
  um: Mark install_fatal_handler as __init
  um: Mark set_stklim as __init
  um: Mark get_top_address as __init
  um: Mark parse_cache_line as __init
  um: Mark parse_host_cpu_flags as __init
  um: Count iomem_size only once in physmem calculation
  um: Remove obsolete fixmap support
  um: Remove unused MODULES_LEN macro

Author: torvalds

arch/um/drivers/rtc_kern.c

@@ -51,14 +51,16 @@ static int uml_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 
 static int uml_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
 {
+	struct timespec64 ts;
 	unsigned long long secs;
 
 	if (!enable && !uml_rtc_alarm_enabled)
 		return 0;
 
 	uml_rtc_alarm_enabled = enable;
 
-	secs = uml_rtc_alarm_time - ktime_get_real_seconds();
+	read_persistent_clock64(&ts);
+	secs = uml_rtc_alarm_time - ts.tv_sec;
 
 	if (time_travel_mode == TT_MODE_OFF) {
 		if (!enable) {
@@ -73,7 +75,8 @@ static int uml_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
 
 		if (enable)
 			time_travel_add_event_rel(&uml_rtc_alarm_event,
-						  secs * NSEC_PER_SEC);
+						  secs * NSEC_PER_SEC -
+						  ts.tv_nsec);
 	}
 
 	return 0;

arch/um/include/asm/fixmap.h

@@ -8,7 +8,8 @@
 #ifndef __UM_PGTABLE_H
 #define __UM_PGTABLE_H
 
-#include <asm/fixmap.h>
+#include <asm/page.h>
+#include <linux/mm_types.h>
 
 #define _PAGE_PRESENT	0x001
 #define _PAGE_NEEDSYNC	0x002
@@ -48,11 +49,9 @@ extern unsigned long end_iomem;
 
 #define VMALLOC_OFFSET	(__va_space)
 #define VMALLOC_START ((end_iomem + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1))
-#define PKMAP_BASE ((FIXADDR_START - LAST_PKMAP * PAGE_SIZE) & PMD_MASK)
-#define VMALLOC_END	(FIXADDR_START-2*PAGE_SIZE)
+#define VMALLOC_END	(TASK_SIZE-2*PAGE_SIZE)
 #define MODULES_VADDR	VMALLOC_START
 #define MODULES_END	VMALLOC_END
-#define MODULES_LEN	(MODULES_VADDR - MODULES_END)
 
 #define _PAGE_TABLE	(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED | _PAGE_DIRTY)
 #define _KERNPG_TABLE	(_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)

arch/um/include/asm/pgtable.h

@@ -9,7 +9,6 @@
 #include <linux/mm.h>
 #include <linux/swap.h>
 #include <linux/slab.h>
-#include <asm/fixmap.h>
 #include <asm/page.h>
 #include <asm/pgalloc.h>
 #include <as-layout.h>
@@ -74,6 +73,7 @@ void __init mem_init(void)
 	kmalloc_ok = 1;
 }
 
+#if IS_ENABLED(CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA)
 /*
  * Create a page table and place a pointer to it in a middle page
  * directory entry.
@@ -152,7 +152,6 @@ static void __init fixrange_init(unsigned long start, unsigned long end,
 
 static void __init fixaddr_user_init( void)
 {
-#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
 	long size = FIXADDR_USER_END - FIXADDR_USER_START;
 	pte_t *pte;
 	phys_t p;
@@ -174,13 +173,12 @@ static void __init fixaddr_user_init( void)
 		pte = virt_to_kpte(vaddr);
 		pte_set_val(*pte, p, PAGE_READONLY);
 	}
-#endif
 }
+#endif
 
 void __init paging_init(void)
 {
 	unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
-	unsigned long vaddr;
 
 	empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE,
 							       PAGE_SIZE);
@@ -191,14 +189,9 @@ void __init paging_init(void)
 	max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT;
 	free_area_init(max_zone_pfn);
 
-	/*
-	 * Fixed mappings, only the page table structure has to be
-	 * created - mappings will be set by set_fixmap():
-	 */
-	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
-	fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
-
+#if IS_ENABLED(CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA)
 	fixaddr_user_init();
+#endif
 }
 
 /*

arch/um/kernel/mem.c

@@ -213,14 +213,6 @@ int __uml_cant_sleep(void) {
 	/* Is in_interrupt() really needed? */
 }
 
-int user_context(unsigned long sp)
-{
-	unsigned long stack;
-
-	stack = sp & (PAGE_MASK << CONFIG_KERNEL_STACK_ORDER);
-	return stack != (unsigned long) current_thread_info();
-}
-
 extern exitcall_t __uml_exitcall_begin, __uml_exitcall_end;
 
 void do_uml_exitcalls(void)

arch/um/kernel/process.c

@@ -264,15 +264,16 @@ EXPORT_SYMBOL(end_iomem);
 
 #define MIN_VMALLOC (32 * 1024 * 1024)
 
-static void parse_host_cpu_flags(char *line)
+static void __init parse_host_cpu_flags(char *line)
 {
 	int i;
 	for (i = 0; i < 32*NCAPINTS; i++) {
 		if ((x86_cap_flags[i] != NULL) && strstr(line, x86_cap_flags[i]))
 			set_cpu_cap(&boot_cpu_data, i);
 	}
 }
-static void parse_cache_line(char *line)
+
+static void __init parse_cache_line(char *line)
 {
 	long res;
 	char *to_parse = strstr(line, ":");
@@ -288,7 +289,7 @@ static void parse_cache_line(char *line)
 	}
 }
 
-static unsigned long get_top_address(char **envp)
+static unsigned long __init get_top_address(char **envp)
 {
 	unsigned long top_addr = (unsigned long) &top_addr;
 	int i;
@@ -376,9 +377,8 @@ int __init linux_main(int argc, char **argv, char **envp)
 	iomem_size = (iomem_size + PAGE_SIZE - 1) & PAGE_MASK;
 
 	max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC;
-
-	if (physmem_size + iomem_size > max_physmem) {
-		physmem_size = max_physmem - iomem_size;
+	if (physmem_size > max_physmem) {
+		physmem_size = max_physmem;
 		os_info("Physical memory size shrunk to %llu bytes\n",
 			physmem_size);
 	}

arch/um/kernel/um_arch.c

@@ -19,13 +19,11 @@
 #include <um_malloc.h>
 #include "internal.h"
 
-#define PGD_BOUND (4 * 1024 * 1024)
 #define STACKSIZE (8 * 1024 * 1024)
-#define THREAD_NAME_LEN (256)
 
 long elf_aux_hwcap;
 
-static void set_stklim(void)
+static void __init set_stklim(void)
 {
 	struct rlimit lim;
 
@@ -48,7 +46,7 @@ static void last_ditch_exit(int sig)
 	exit(1);
 }
 
-static void install_fatal_handler(int sig)
+static void __init install_fatal_handler(int sig)
 {
 	struct sigaction action;
 
@@ -73,7 +71,7 @@ static void install_fatal_handler(int sig)
 
 #define UML_LIB_PATH	":" OS_LIB_PATH "/uml"
 
-static void setup_env_path(void)
+static void __init setup_env_path(void)
 {
 	char *new_path = NULL;
 	char *old_path = NULL;

arch/um/os-Linux/main.c

@@ -74,8 +74,6 @@ struct uml_pt_regs {
 #define UPT_FAULTINFO(r) (&(r)->faultinfo)
 #define UPT_IS_USER(r) ((r)->is_user)
 
-extern int user_context(unsigned long sp);
-
 extern int arch_init_registers(int pid);
 
 #endif /* __SYSDEP_X86_PTRACE_H */

arch/x86/um/asm/archparam.h

@@ -410,38 +410,33 @@ static const struct file_operations hostfs_dir_fops = {
 	.fsync		= hostfs_fsync,
 };
 
-static int hostfs_writepage(struct page *page, struct writeback_control *wbc)
+static int hostfs_writepages(struct address_space *mapping,
+		struct writeback_control *wbc)
 {
-	struct address_space *mapping = page->mapping;
 	struct inode *inode = mapping->host;
-	char *buffer;
-	loff_t base = page_offset(page);
-	int count = PAGE_SIZE;
-	int end_index = inode->i_size >> PAGE_SHIFT;
-	int err;
-
-	if (page->index >= end_index)
-		count = inode->i_size & (PAGE_SIZE-1);
-
-	buffer = kmap_local_page(page);
-
-	err = write_file(HOSTFS_I(inode)->fd, &base, buffer, count);
-	if (err != count) {
-		if (err >= 0)
-			err = -EIO;
-		mapping_set_error(mapping, err);
-		goto out;
+	struct folio *folio = NULL;
+	loff_t i_size = i_size_read(inode);
+	int err = 0;
+
+	while ((folio = writeback_iter(mapping, wbc, folio, &err))) {
+		loff_t pos = folio_pos(folio);
+		size_t count = folio_size(folio);
+		char *buffer;
+		int ret;
+
+		if (count > i_size - pos)
+			count = i_size - pos;
+
+		buffer = kmap_local_folio(folio, 0);
+		ret = write_file(HOSTFS_I(inode)->fd, &pos, buffer, count);
+		kunmap_local(buffer);
+		folio_unlock(folio);
+		if (ret != count) {
+			err = ret < 0 ? ret : -EIO;
+			mapping_set_error(mapping, err);
+		}
 	}
 
-	if (base > inode->i_size)
-		inode->i_size = base;
-
-	err = 0;
-
- out:
-	kunmap_local(buffer);
-	unlock_page(page);
-
 	return err;
 }
 
@@ -506,11 +501,12 @@ static int hostfs_write_end(struct file *file, struct address_space *mapping,
 }
 
 static const struct address_space_operations hostfs_aops = {
-	.writepage 	= hostfs_writepage,
+	.writepages 	= hostfs_writepages,
 	.read_folio	= hostfs_read_folio,
 	.dirty_folio	= filemap_dirty_folio,
 	.write_begin	= hostfs_write_begin,
 	.write_end	= hostfs_write_end,
+	.migrate_folio	= filemap_migrate_folio,
 };
 
 static int hostfs_inode_update(struct inode *ino, const struct hostfs_stat *st)