Merge ../linus

66 files changed, 1124 insertions, 416 deletions

diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 5982fe2753e..05fbb20636c 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -22,6 +22,9 @@ config SBUS
 config PCI
 	bool
 
+config PCMCIA
+	bool
+
 config GENERIC_CALIBRATE_DELAY
 	bool
 	default y
diff --git a/arch/um/Makefile b/arch/um/Makefile
index 8d14c7a831b..a508e7a0289 100644
--- a/arch/um/Makefile
+++ b/arch/um/Makefile
@@ -20,7 +20,7 @@ core-y			+= $(ARCH_DIR)/kernel/		\
 
 # Have to precede the include because the included Makefiles reference them.
 SYMLINK_HEADERS := archparam.h system.h sigcontext.h processor.h ptrace.h \
-	module.h vm-flags.h elf.h ldt.h
+	module.h vm-flags.h elf.h host_ldt.h
 SYMLINK_HEADERS := $(foreach header,$(SYMLINK_HEADERS),include/asm-um/$(header))
 
 # XXX: The "os" symlink is only used by arch/um/include/os.h, which includes
@@ -129,7 +129,7 @@ CPPFLAGS_vmlinux.lds = -U$(SUBARCH) \
 	-DSTART=$(START) -DELF_ARCH=$(ELF_ARCH) \
 	-DELF_FORMAT="$(ELF_FORMAT)" $(CPP_MODE-y) \
 	-DKERNEL_STACK_SIZE=$(STACK_SIZE) \
-	-DUNMAP_PATH=arch/um/sys-$(SUBARCH)/unmap_fin.o
+	-DUNMAP_PATH=arch/um/sys-$(SUBARCH)/unmap.o
 
 #The wrappers will select whether using "malloc" or the kernel allocator.
 LINK_WRAPS = -Wl,--wrap,malloc -Wl,--wrap,free -Wl,--wrap,calloc
@@ -150,8 +150,7 @@ CLEAN_FILES += linux x.i gmon.out $(ARCH_DIR)/include/uml-config.h \
 	$(ARCH_DIR)/include/user_constants.h \
 	$(ARCH_DIR)/include/kern_constants.h $(ARCH_DIR)/Kconfig.arch
 
-MRPROPER_FILES += $(SYMLINK_HEADERS) $(ARCH_SYMLINKS) \
-	$(addprefix $(ARCH_DIR)/kernel/,$(KERN_SYMLINKS)) $(ARCH_DIR)/os
+MRPROPER_FILES += $(ARCH_SYMLINKS)
 
 archclean:
 	@find . \( -name '*.bb' -o -name '*.bbg' -o -name '*.da' \
@@ -160,6 +159,7 @@ archclean:
 $(SYMLINK_HEADERS):
 	@echo '  SYMLINK $@'
 ifneq ($(KBUILD_SRC),)
+	$(Q)mkdir -p $(objtree)/include/asm-um
 	$(Q)ln -fsn $(srctree)/include/asm-um/$(basename $(notdir $@))-$(SUBARCH)$(suffix $@) $@
 else
 	$(Q)cd $(TOPDIR)/$(dir $@) ; \
@@ -169,7 +169,7 @@ endif
 include/asm-um/arch:
 	@echo '  SYMLINK $@'
 ifneq ($(KBUILD_SRC),)
-	$(Q)mkdir -p include/asm-um
+	$(Q)mkdir -p $(objtree)/include/asm-um
 	$(Q)ln -fsn $(srctree)/include/asm-$(SUBARCH) include/asm-um/arch
 else
 	$(Q)cd $(TOPDIR)/include/asm-um && ln -sf ../asm-$(SUBARCH) arch
diff --git a/arch/um/Makefile-x86_64 b/arch/um/Makefile-x86_64
index 38df311e75d..dfd88b652fb 100644
--- a/arch/um/Makefile-x86_64
+++ b/arch/um/Makefile-x86_64
@@ -1,7 +1,7 @@
 # Copyright 2003 - 2004 Pathscale, Inc
 # Released under the GPL
 
-libs-y += arch/um/sys-x86_64/
+core-y += arch/um/sys-x86_64/
 START := 0x60000000
 
 #We #undef __x86_64__ for kernelspace, not for userspace where
diff --git a/arch/um/drivers/cow.h b/arch/um/drivers/cow.h
index 04e3958266e..dc36b222100 100644
--- a/arch/um/drivers/cow.h
+++ b/arch/um/drivers/cow.h
@@ -46,7 +46,7 @@ extern int file_reader(__u64 offset, char *buf, int len, void *arg);
 extern int read_cow_header(int (*reader)(__u64, char *, int, void *),
 			   void *arg, __u32 *version_out,
 			   char **backing_file_out, time_t *mtime_out,
-			   __u64 *size_out, int *sectorsize_out,
+			   unsigned long long *size_out, int *sectorsize_out,
 			   __u32 *align_out, int *bitmap_offset_out);
 
 extern int write_cow_header(char *cow_file, int fd, char *backing_file,
diff --git a/arch/um/drivers/cow_sys.h b/arch/um/drivers/cow_sys.h
index 94de4ead4f7..7a5b4afde69 100644
--- a/arch/um/drivers/cow_sys.h
+++ b/arch/um/drivers/cow_sys.h
@@ -28,7 +28,7 @@ static inline int cow_seek_file(int fd, __u64 offset)
 	return(os_seek_file(fd, offset));
 }
 
-static inline int cow_file_size(char *file, __u64 *size_out)
+static inline int cow_file_size(char *file, unsigned long long *size_out)
 {
 	return(os_file_size(file, size_out));
 }
diff --git a/arch/um/drivers/cow_user.c b/arch/um/drivers/cow_user.c
index 61951b72126..0ec4052db9c 100644
--- a/arch/um/drivers/cow_user.c
+++ b/arch/um/drivers/cow_user.c
@@ -17,30 +17,34 @@
 
 #define PATH_LEN_V1 256
 
+typedef __u32 time32_t;
+
 struct cow_header_v1 {
-	int magic;
-	int version;
+	__s32 magic;
+	__s32 version;
 	char backing_file[PATH_LEN_V1];
-	time_t mtime;
+	time32_t mtime;
 	__u64 size;
-	int sectorsize;
-};
+	__s32 sectorsize;
+} __attribute__((packed));
 
-#define PATH_LEN_V2 MAXPATHLEN
+/* Define PATH_LEN_V3 as the usual value of MAXPATHLEN, just hard-code it in
+ * case other systems have different values for MAXPATHLEN.
+ *
+ * The same must hold for V2 - we want file format compatibility, not anything
+ * else.
+ */
+#define PATH_LEN_V3 4096
+#define PATH_LEN_V2 PATH_LEN_V3
 
 struct cow_header_v2 {
 	__u32 magic;
 	__u32 version;
 	char backing_file[PATH_LEN_V2];
-	time_t mtime;
+	time32_t mtime;
 	__u64 size;
-	int sectorsize;
-};
-
-/* Define PATH_LEN_V3 as the usual value of MAXPATHLEN, just hard-code it in
- * case other systems have different values for MAXPATHLEN
- */
-#define PATH_LEN_V3 4096
+	__s32 sectorsize;
+} __attribute__((packed));
 
 /* Changes from V2 -
  *	PATH_LEN_V3 as described above
@@ -66,6 +70,15 @@ struct cow_header_v2 {
  *	Fixed (finally!) the rounding bug
  */
 
+/* Until Dec2005, __attribute__((packed)) was left out from the below
+ * definition, leading on 64-bit systems to 4 bytes of padding after mtime, to
+ * align size to 8-byte alignment.  This shifted all fields above (no padding
+ * was present on 32-bit, no other padding was added).
+ *
+ * However, this _can be detected_: it means that cow_format (always 0 until
+ * now) is shifted onto the first 4 bytes of backing_file, where it is otherwise
+ * impossible to find 4 zeros. -bb */
+
 struct cow_header_v3 {
 	__u32 magic;
 	__u32 version;
@@ -75,6 +88,18 @@ struct cow_header_v3 {
 	__u32 alignment;
 	__u32 cow_format;
 	char backing_file[PATH_LEN_V3];
+} __attribute__((packed));
+
+/* This is the broken layout used by some 64-bit binaries. */
+struct cow_header_v3_broken {
+	__u32 magic;
+	__u32 version;
+	__s64 mtime;
+	__u64 size;
+	__u32 sectorsize;
+	__u32 alignment;
+	__u32 cow_format;
+	char backing_file[PATH_LEN_V3];
 };
 
 /* COW format definitions - for now, we have only the usual COW bitmap */
@@ -84,6 +109,7 @@ union cow_header {
 	struct cow_header_v1 v1;
 	struct cow_header_v2 v2;
 	struct cow_header_v3 v3;
+	struct cow_header_v3_broken v3_b;
 };
 
 #define COW_MAGIC 0x4f4f4f4d  /* MOOO */
@@ -184,8 +210,9 @@ int write_cow_header(char *cow_file, int fd, char *backing_file,
 
 	err = -EINVAL;
 	if(strlen(backing_file) > sizeof(header->backing_file) - 1){
+		/* Below, %zd is for a size_t value */
 		cow_printf("Backing file name \"%s\" is too long - names are "
-			   "limited to %d characters\n", backing_file,
+			   "limited to %zd characters\n", backing_file,
 			   sizeof(header->backing_file) - 1);
 		goto out_free;
 	}
@@ -300,7 +327,8 @@ int read_cow_header(int (*reader)(__u64, char *, int, void *), void *arg,
 		*align_out = *sectorsize_out;
 		file = header->v2.backing_file;
 	}
-	else if(version == 3){
+	/* This is very subtle - see above at union cow_header definition */
+	else if(version == 3 && (*((int*)header->v3.backing_file) != 0)){
 		if(n < sizeof(header->v3)){
 			cow_printf("read_cow_header - failed to read V3 "
 				   "header\n");
@@ -310,9 +338,43 @@ int read_cow_header(int (*reader)(__u64, char *, int, void *), void *arg,
 		*size_out = ntohll(header->v3.size);
 		*sectorsize_out = ntohl(header->v3.sectorsize);
 		*align_out = ntohl(header->v3.alignment);
+		if (*align_out == 0) {
+			cow_printf("read_cow_header - invalid COW header, "
+				   "align == 0\n");
+		}
 		*bitmap_offset_out = ROUND_UP(sizeof(header->v3), *align_out);
 		file = header->v3.backing_file;
 	}
+	else if(version == 3){
+		cow_printf("read_cow_header - broken V3 file with"
+			   " 64-bit layout - recovering content.\n");
+
+		if(n < sizeof(header->v3_b)){
+			cow_printf("read_cow_header - failed to read V3 "
+				   "header\n");
+			goto out;
+		}
+
+		/* this was used until Dec2005 - 64bits are needed to represent
+		 * 2038+. I.e. we can safely do this truncating cast.
+		 *
+		 * Additionally, we must use ntohl() instead of ntohll(), since
+		 * the program used to use the former (tested - I got mtime
+		 * mismatch "0 vs whatever").
+		 *
+		 * Ever heard about bug-to-bug-compatibility ? ;-) */
+		*mtime_out = (time32_t) ntohl(header->v3_b.mtime);
+
+		*size_out = ntohll(header->v3_b.size);
+		*sectorsize_out = ntohl(header->v3_b.sectorsize);
+		*align_out = ntohl(header->v3_b.alignment);
+		if (*align_out == 0) {
+			cow_printf("read_cow_header - invalid COW header, "
+				   "align == 0\n");
+		}
+		*bitmap_offset_out = ROUND_UP(sizeof(header->v3_b), *align_out);
+		file = header->v3_b.backing_file;
+	}
 	else {
 		cow_printf("read_cow_header - invalid COW version\n");
 		goto out;
diff --git a/arch/um/drivers/daemon_kern.c b/arch/um/drivers/daemon_kern.c
index a61b7b46bc0..53d09ed78b4 100644
--- a/arch/um/drivers/daemon_kern.c
+++ b/arch/um/drivers/daemon_kern.c
@@ -95,18 +95,7 @@ static struct transport daemon_transport = {
 static int register_daemon(void)
 {
 	register_transport(&daemon_transport);
-	return(1);
+	return 0;
 }
 
 __initcall(register_daemon);
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
diff --git a/arch/um/drivers/harddog_kern.c b/arch/um/drivers/harddog_kern.c
index 49acb2badf3..d18a974735e 100644
--- a/arch/um/drivers/harddog_kern.c
+++ b/arch/um/drivers/harddog_kern.c
@@ -104,7 +104,7 @@ static int harddog_release(struct inode *inode, struct file *file)
 
 extern int ping_watchdog(int fd);
 
-static ssize_t harddog_write(struct file *file, const char *data, size_t len,
+static ssize_t harddog_write(struct file *file, const char __user *data, size_t len,
 			     loff_t *ppos)
 {
 	/*
@@ -118,6 +118,7 @@ static ssize_t harddog_write(struct file *file, const char *data, size_t len,
 static int harddog_ioctl(struct inode *inode, struct file *file,
 			 unsigned int cmd, unsigned long arg)
 {
+	void __user *argp= (void __user *)arg;
 	static struct watchdog_info ident = {
 		WDIOC_SETTIMEOUT,
 		0,
@@ -127,13 +128,12 @@ static int harddog_ioctl(struct inode *inode, struct file *file,
 		default:
 			return -ENOTTY;
 		case WDIOC_GETSUPPORT:
-			if(copy_to_user((struct harddog_info *)arg, &ident,
-					sizeof(ident)))
+			if(copy_to_user(argp, &ident, sizeof(ident)))
 				return -EFAULT;
 			return 0;
 		case WDIOC_GETSTATUS:
 		case WDIOC_GETBOOTSTATUS:
-			return put_user(0,(int *)arg);
+			return put_user(0,(int __user *)argp);
 		case WDIOC_KEEPALIVE:
 			return(ping_watchdog(harddog_out_fd));
 	}
diff --git a/arch/um/drivers/hostaudio_kern.c b/arch/um/drivers/hostaudio_kern.c
index 59602b81b24..37232f908cd 100644
--- a/arch/um/drivers/hostaudio_kern.c
+++ b/arch/um/drivers/hostaudio_kern.c
@@ -67,8 +67,8 @@ MODULE_PARM_DESC(mixer, MIXER_HELP);
 
 /* /dev/dsp file operations */
 
-static ssize_t hostaudio_read(struct file *file, char *buffer, size_t count, 
-			      loff_t *ppos)
+static ssize_t hostaudio_read(struct file *file, char __user *buffer,
+			      size_t count, loff_t *ppos)
 {
         struct hostaudio_state *state = file->private_data;
 	void *kbuf;
@@ -94,7 +94,7 @@ static ssize_t hostaudio_read(struct file *file, char *buffer, size_t count,
 	return(err);
 }
 
-static ssize_t hostaudio_write(struct file *file, const char *buffer, 
+static ssize_t hostaudio_write(struct file *file, const char __user *buffer,
 			       size_t count, loff_t *ppos)
 {
         struct hostaudio_state *state = file->private_data;
@@ -152,7 +152,7 @@ static int hostaudio_ioctl(struct inode *inode, struct file *file,
 	case SNDCTL_DSP_CHANNELS:
 	case SNDCTL_DSP_SUBDIVIDE:
 	case SNDCTL_DSP_SETFRAGMENT:
-		if(get_user(data, (int *) arg))
+		if(get_user(data, (int __user *) arg))
 			return(-EFAULT);
 		break;
 	default:
@@ -168,7 +168,7 @@ static int hostaudio_ioctl(struct inode *inode, struct file *file,
 	case SNDCTL_DSP_CHANNELS:
 	case SNDCTL_DSP_SUBDIVIDE:
 	case SNDCTL_DSP_SETFRAGMENT:
-		if(put_user(data, (int *) arg))
+		if(put_user(data, (int __user *) arg))
 			return(-EFAULT);
 		break;
 	default:
diff --git a/arch/um/drivers/mcast_kern.c b/arch/um/drivers/mcast_kern.c
index c9b078fba03..3a7af18cf94 100644
--- a/arch/um/drivers/mcast_kern.c
+++ b/arch/um/drivers/mcast_kern.c
@@ -124,18 +124,7 @@ static struct transport mcast_transport = {
 static int register_mcast(void)
 {
 	register_transport(&mcast_transport);
-	return(1);
+	return 0;
 }
 
 __initcall(register_mcast);
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index 1488816588e..6d7173fc55a 100644
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -20,6 +20,8 @@
 #include "linux/namei.h"
 #include "linux/proc_fs.h"
 #include "linux/syscalls.h"
+#include "linux/list.h"
+#include "linux/mm.h"
 #include "linux/console.h"
 #include "asm/irq.h"
 #include "asm/uaccess.h"
@@ -60,7 +62,7 @@ static void mc_work_proc(void *unused)
 	unsigned long flags;
 
 	while(!list_empty(&mc_requests)){
-		local_save_flags(flags);
+		local_irq_save(flags);
 		req = list_entry(mc_requests.next, struct mconsole_entry,
 				 list);
 		list_del(&req->list);
@@ -85,7 +87,7 @@ static irqreturn_t mconsole_interrupt(int irq, void *dev_id,
 		if(req.cmd->context == MCONSOLE_INTR)
 			(*req.cmd->handler)(&req);
 		else {
-			new = kmalloc(sizeof(*new), GFP_ATOMIC);
+			new = kmalloc(sizeof(*new), GFP_NOWAIT);
 			if(new == NULL)
 				mconsole_reply(&req, "Out of memory", 1, 0);
 			else {
@@ -347,6 +349,141 @@ static struct mc_device *mconsole_find_dev(char *name)
 	return(NULL);
 }
 
+#define UNPLUGGED_PER_PAGE \
+	((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
+
+struct unplugged_pages {
+	struct list_head list;
+	void *pages[UNPLUGGED_PER_PAGE];
+};
+
+static unsigned long long unplugged_pages_count = 0;
+static struct list_head unplugged_pages = LIST_HEAD_INIT(unplugged_pages);
+static int unplug_index = UNPLUGGED_PER_PAGE;
+
+static int mem_config(char *str)
+{
+	unsigned long long diff;
+	int err = -EINVAL, i, add;
+	char *ret;
+
+	if(str[0] != '=')
+		goto out;
+
+	str++;
+	if(str[0] == '-')
+		add = 0;
+	else if(str[0] == '+'){
+		add = 1;
+	}
+	else goto out;
+
+	str++;
+	diff = memparse(str, &ret);
+	if(*ret != '\0')
+		goto out;
+
+	diff /= PAGE_SIZE;
+
+	for(i = 0; i < diff; i++){
+		struct unplugged_pages *unplugged;
+		void *addr;
+
+		if(add){
+			if(list_empty(&unplugged_pages))
+				break;
+
+			unplugged = list_entry(unplugged_pages.next,
+					       struct unplugged_pages, list);
+			if(unplug_index > 0)
+				addr = unplugged->pages[--unplug_index];
+			else {
+				list_del(&unplugged->list);
+				addr = unplugged;
+				unplug_index = UNPLUGGED_PER_PAGE;
+			}
+
+			free_page((unsigned long) addr);
+			unplugged_pages_count--;
+		}
+		else {
+			struct page *page;
+
+			page = alloc_page(GFP_ATOMIC);
+			if(page == NULL)
+				break;
+
+			unplugged = page_address(page);
+			if(unplug_index == UNPLUGGED_PER_PAGE){
+				list_add(&unplugged->list, &unplugged_pages);
+				unplug_index = 0;
+			}
+			else {
+				struct list_head *entry = unplugged_pages.next;
+				addr = unplugged;
+
+				unplugged = list_entry(entry,
+						       struct unplugged_pages,
+						       list);
+				unplugged->pages[unplug_index++] = addr;
+				err = os_drop_memory(addr, PAGE_SIZE);
+				if(err)
+					printk("Failed to release memory - "
+					       "errno = %d\n", err);
+			}
+
+			unplugged_pages_count++;
+		}
+	}
+
+	err = 0;
+out:
+	return err;
+}
+
+static int mem_get_config(char *name, char *str, int size, char **error_out)
+{
+	char buf[sizeof("18446744073709551615")];
+	int len = 0;
+
+	sprintf(buf, "%ld", uml_physmem);
+	CONFIG_CHUNK(str, size, len, buf, 1);
+
+	return len;
+}
+
+static int mem_id(char **str, int *start_out, int *end_out)
+{
+	*start_out = 0;
+	*end_out = 0;
+
+	return 0;
+}
+
+static int mem_remove(int n)
+{
+	return -EBUSY;
+}
+
+static struct mc_device mem_mc = {
+	.name		= "mem",
+	.config		= mem_config,
+	.get_config	= mem_get_config,
+	.id		= mem_id,
+	.remove		= mem_remove,
+};
+
+static int mem_mc_init(void)
+{
+	if(can_drop_memory())
+		mconsole_register_dev(&mem_mc);
+	else printk("Can't release memory to the host - memory hotplug won't "
+		    "be supported\n");
+	return 0;
+}
+
+__initcall(mem_mc_init);
+
 #define CONFIG_BUF_SIZE 64
 
 static void mconsole_get_config(int (*get_config)(char *, char *, int,
@@ -478,7 +615,7 @@ static void console_write(struct console *console, const char *string,
 		return;
 
 	while(1){
-		n = min(len, ARRAY_SIZE(console_buf) - console_index);
+		n = min((size_t) len, ARRAY_SIZE(console_buf) - console_index);
 		strncpy(&console_buf[console_index], string, n);
 		console_index += n;
 		string += n;
@@ -517,7 +654,6 @@ static void with_console(struct mc_request *req, void (*proc)(void *),
 	struct mconsole_entry entry;
 	unsigned long flags;
 
-	INIT_LIST_HEAD(&entry.list);
 	entry.request = *req;
 	list_add(&entry.list, &clients);
 	spin_lock_irqsave(&console_lock, flags);
diff --git a/arch/um/drivers/net_user.c b/arch/um/drivers/net_user.c
index 0e2f06187ea..0a7786e00cf 100644
--- a/arch/um/drivers/net_user.c
+++ b/arch/um/drivers/net_user.c
@@ -182,7 +182,9 @@ static int change_tramp(char **argv, char *output, int output_len)
 	pe_data.stdout = fds[1];
 	pid = run_helper(change_pre_exec, &pe_data, argv, NULL);
 
-	read_output(fds[0], output, output_len);
+	if (pid > 0)	/* Avoid hang as we won't get data in failure case. */
+		read_output(fds[0], output, output_len);
+
 	os_close_file(fds[0]);
 	os_close_file(fds[1]);
 
diff --git a/arch/um/drivers/pcap_kern.c b/arch/um/drivers/pcap_kern.c
index 07c80f2156e..466ff2c2f91 100644
--- a/arch/um/drivers/pcap_kern.c
+++ b/arch/um/drivers/pcap_kern.c
@@ -106,18 +106,7 @@ static struct transport pcap_transport = {
 static int register_pcap(void)
 {
 	register_transport(&pcap_transport);
-	return(1);
+	return 0;
 }
 
 __initcall(register_pcap);
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
diff --git a/arch/um/drivers/slip_kern.c b/arch/um/drivers/slip_kern.c
index a62f5ef445c..163ee0d5f75 100644
--- a/arch/um/drivers/slip_kern.c
+++ b/arch/um/drivers/slip_kern.c
@@ -93,18 +93,7 @@ static struct transport slip_transport = {
 static int register_slip(void)
 {
 	register_transport(&slip_transport);
-	return(1);
+	return 0;
 }
 
 __initcall(register_slip);
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
diff --git a/arch/um/drivers/slirp_kern.c b/arch/um/drivers/slirp_kern.c
index 33d7982be5d..95e50c943e1 100644
--- a/arch/um/drivers/slirp_kern.c
+++ b/arch/um/drivers/slirp_kern.c
@@ -77,7 +77,7 @@ static int slirp_setup(char *str, char **mac_out, void *data)
 	int i=0;
 
 	*init = ((struct slirp_init)
-		{ argw :		{ { "slirp", NULL  } } });
+		{ .argw = { { "slirp", NULL  } } });
 
 	str = split_if_spec(str, mac_out, NULL);
 
@@ -116,18 +116,7 @@ static struct transport slirp_transport = {
 static int register_slirp(void)
 {
 	register_transport(&slirp_transport);
-	return(1);
+	return 0;
 }
 
 __initcall(register_slirp);
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
diff --git a/arch/um/drivers/slirp_user.c b/arch/um/drivers/slirp_user.c
index b94c66114bc..33c5f6e625e 100644
--- a/arch/um/drivers/slirp_user.c
+++ b/arch/um/drivers/slirp_user.c
@@ -104,7 +104,7 @@ static void slirp_close(int fd, void *data)
 	}
 
 	if(err == 0) {
-		printk("slirp_close: process %d has not exited\n");
+		printk("slirp_close: process %d has not exited\n", pri->pid);
 		return;
 	}
 
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 0336575d244..0897852b09a 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -891,7 +891,7 @@ int ubd_driver_init(void){
 			     SA_INTERRUPT, "ubd", ubd_dev);
 	if(err != 0)
 		printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err);
-	return(err);
+	return 0;
 }
 
 device_initcall(ubd_driver_init);
diff --git a/arch/um/include/kern_util.h b/arch/um/include/kern_util.h
index 07176d92e1c..efa3d33c0be 100644
--- a/arch/um/include/kern_util.h
+++ b/arch/um/include/kern_util.h
@@ -116,7 +116,7 @@ extern void *get_current(void);
 extern struct task_struct *get_task(int pid, int require);
 extern void machine_halt(void);
 extern int is_syscall(unsigned long addr);
-extern void arch_switch(void);
+
 extern void free_irq(unsigned int, void *);
 extern int cpu(void);
 
diff --git a/arch/um/include/line.h b/arch/um/include/line.h
index 6f4d680dc1d..6ac0f8252e2 100644
--- a/arch/um/include/line.h
+++ b/arch/um/include/line.h
@@ -58,23 +58,17 @@ struct line {
 };
 
 #define LINE_INIT(str, d) \
-	{ init_str :	str, \
-	  init_pri :	INIT_STATIC, \
-	  valid :	1, \
-	  throttled :	0, \
-	  lock :	SPIN_LOCK_UNLOCKED, \
-	  buffer :	NULL, \
-	  head :	NULL, \
-	  tail :	NULL, \
-	  sigio :	0, \
-	  driver :	d, \
-	  have_irq :	0 }
+	{ .init_str =	str, \
+	  .init_pri =	INIT_STATIC, \
+	  .valid =	1, \
+	  .lock =	SPIN_LOCK_UNLOCKED, \
+	  .driver =	d }
 
 struct lines {
 	int num;
 };
 
-#define LINES_INIT(n) {  num :		n }
+#define LINES_INIT(n) {  .num =	n }
 
 extern void line_close(struct tty_struct *tty, struct file * filp);
 extern int line_open(struct line *lines, struct tty_struct *tty);
diff --git a/arch/um/include/mem_user.h b/arch/um/include/mem_user.h
index a1064c5823b..a54514d2cc3 100644
--- a/arch/um/include/mem_user.h
+++ b/arch/um/include/mem_user.h
@@ -49,7 +49,6 @@ extern int iomem_size;
 extern unsigned long host_task_size;
 extern unsigned long task_size;
 
-extern void check_devanon(void);
 extern int init_mem_user(void);
 extern void setup_memory(void *entry);
 extern unsigned long find_iomem(char *driver, unsigned long *len_out);
diff --git a/arch/um/include/os.h b/arch/um/include/os.h
index d3d1bc6074e..f88856c28a6 100644
--- a/arch/um/include/os.h
+++ b/arch/um/include/os.h
@@ -13,6 +13,7 @@
 #include "kern_util.h"
 #include "skas/mm_id.h"
 #include "irq_user.h"
+#include "sysdep/tls.h"
 
 #define OS_TYPE_FILE 1 
 #define OS_TYPE_DIR 2 
@@ -172,6 +173,7 @@ extern int os_fchange_dir(int fd);
 extern void os_early_checks(void);
 extern int can_do_skas(void);
 extern void os_check_bugs(void);
+extern void check_host_supports_tls(int *supports_tls, int *tls_min);
 
 /* Make sure they are clear when running in TT mode. Required by
  * SEGV_MAYBE_FIXABLE */
@@ -205,6 +207,8 @@ extern int os_map_memory(void *virt, int fd, unsigned long long off,
 extern int os_protect_memory(void *addr, unsigned long len, 
 			     int r, int w, int x);
 extern int os_unmap_memory(void *addr, int len);
+extern int os_drop_memory(void *addr, int length);
+extern int can_drop_memory(void);
 extern void os_flush_stdout(void);
 
 /* tt.c
@@ -234,8 +238,12 @@ extern int run_helper_thread(int (*proc)(void *), void *arg,
 			     int stack_order);
 extern int helper_wait(int pid);
 
-/* umid.c */
 
+/* tls.c */
+extern int os_set_thread_area(user_desc_t *info, int pid);
+extern int os_get_thread_area(user_desc_t *info, int pid);
+
+/* umid.c */
 extern int umid_file_name(char *name, char *buf, int len);
 extern int set_umid(char *name);
 extern char *get_umid(void);
diff --git a/arch/um/include/sysdep-i386/checksum.h b/arch/um/include/sysdep-i386/checksum.h
index 7d3d202d7ff..052bb061a97 100644
--- a/arch/um/include/sysdep-i386/checksum.h
+++ b/arch/um/include/sysdep-i386/checksum.h
@@ -48,7 +48,8 @@ unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *
  */
 
 static __inline__
-unsigned int csum_partial_copy_from_user(const unsigned char *src, unsigned char *dst,
+unsigned int csum_partial_copy_from_user(const unsigned char __user *src,
+					 unsigned char *dst,
 					 int len, int sum, int *err_ptr)
 {
 	if(copy_from_user(dst, src, len)){
@@ -192,7 +193,7 @@ static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
  */
 #define HAVE_CSUM_COPY_USER
 static __inline__ unsigned int csum_and_copy_to_user(const unsigned char *src,
-						     unsigned char *dst,
+						     unsigned char __user *dst,
 						     int len, int sum, int *err_ptr)
 {
 	if (access_ok(VERIFY_WRITE, dst, len)){
diff --git a/arch/um/include/sysdep-i386/ptrace.h b/arch/um/include/sysdep-i386/ptrace.h
index c8ee9559f3a..6670cc992ec 100644
--- a/arch/um/include/sysdep-i386/ptrace.h
+++ b/arch/um/include/sysdep-i386/ptrace.h
@@ -14,7 +14,12 @@
 #define MAX_REG_NR (UM_FRAME_SIZE / sizeof(unsigned long))
 #define MAX_REG_OFFSET (UM_FRAME_SIZE)
 
+#ifdef UML_CONFIG_PT_PROXY
 extern void update_debugregs(int seq);
+#else
+static inline void update_debugregs(int seq) {}
+#endif
+
 
 /* syscall emulation path in ptrace */
 
diff --git a/arch/um/include/sysdep-i386/tls.h b/arch/um/include/sysdep-i386/tls.h
new file mode 100644
index 00000000000..918fd3c5ff9
--- /dev/null
+++ b/arch/um/include/sysdep-i386/tls.h
@@ -0,0 +1,32 @@
+#ifndef _SYSDEP_TLS_H
+#define _SYSDEP_TLS_H
+
+# ifndef __KERNEL__
+
+/* Change name to avoid conflicts with the original one from <asm/ldt.h>, which
+ * may be named user_desc (but in 2.4 and in header matching its API was named
+ * modify_ldt_ldt_s). */
+
+typedef struct um_dup_user_desc {
+	unsigned int  entry_number;
+	unsigned int  base_addr;
+	unsigned int  limit;
+	unsigned int  seg_32bit:1;
+	unsigned int  contents:2;
+	unsigned int  read_exec_only:1;
+	unsigned int  limit_in_pages:1;
+	unsigned int  seg_not_present:1;
+	unsigned int  useable:1;
+} user_desc_t;
+
+# else /* __KERNEL__ */
+
+#  include <asm/ldt.h>
+typedef struct user_desc user_desc_t;
+
+# endif /* __KERNEL__ */
+
+#define GDT_ENTRY_TLS_MIN_I386 6
+#define GDT_ENTRY_TLS_MIN_X86_64 12
+
+#endif /* _SYSDEP_TLS_H */
diff --git a/arch/um/include/sysdep-x86_64/tls.h b/arch/um/include/sysdep-x86_64/tls.h
new file mode 100644
index 00000000000..35f19f25bd3
--- /dev/null
+++ b/arch/um/include/sysdep-x86_64/tls.h
@@ -0,0 +1,29 @@
+#ifndef _SYSDEP_TLS_H
+#define _SYSDEP_TLS_H
+
+# ifndef __KERNEL__
+
+/* Change name to avoid conflicts with the original one from <asm/ldt.h>, which
+ * may be named user_desc (but in 2.4 and in header matching its API was named
+ * modify_ldt_ldt_s). */
+
+typedef struct um_dup_user_desc {
+	unsigned int  entry_number;
+	unsigned int  base_addr;
+	unsigned int  limit;
+	unsigned int  seg_32bit:1;
+	unsigned int  contents:2;
+	unsigned int  read_exec_only:1;
+	unsigned int  limit_in_pages:1;
+	unsigned int  seg_not_present:1;
+	unsigned int  useable:1;
+	unsigned int  lm:1;
+} user_desc_t;
+
+# else /* __KERNEL__ */
+
+#  include <asm/ldt.h>
+typedef struct user_desc user_desc_t;
+
+# endif /* __KERNEL__ */
+#endif /* _SYSDEP_TLS_H */
diff --git a/arch/um/include/tt/tt.h b/arch/um/include/tt/tt.h
index 80852198018..acb8356e1f9 100644
--- a/arch/um/include/tt/tt.h
+++ b/arch/um/include/tt/tt.h
@@ -19,7 +19,8 @@ extern int fork_tramp(void *sig_stack);
 extern int do_proc_op(void *t, int proc_id);
 extern int tracer(int (*init_proc)(void *), void *sp);
 extern void attach_process(int pid);
-extern void tracer_panic(char *format, ...);
+extern void tracer_panic(char *format, ...)
+	__attribute__ ((format (printf, 1, 2)));
 extern void set_init_pid(int pid);
 extern int set_user_mode(void *task);
 extern void set_tracing(void *t, int tracing);
diff --git a/arch/um/include/user.h b/arch/um/include/user.h
index 91b0ac4ad88..39f8c880107 100644
--- a/arch/um/include/user.h
+++ b/arch/um/include/user.h
@@ -6,8 +6,10 @@
 #ifndef __USER_H__
 #define __USER_H__
 
-extern void panic(const char *fmt, ...);
-extern int printk(const char *fmt, ...);
+extern void panic(const char *fmt, ...)
+	__attribute__ ((format (printf, 1, 2)));
+extern int printk(const char *fmt, ...)
+	__attribute__ ((format (printf, 1, 2)));
 extern void schedule(void);
 extern void *um_kmalloc(int size);
 extern void *um_kmalloc_atomic(int size);
diff --git a/arch/um/include/user_util.h b/arch/um/include/user_util.h
index 992a7e1e0fc..802d7842514 100644
--- a/arch/um/include/user_util.h
+++ b/arch/um/include/user_util.h
@@ -8,6 +8,9 @@
 
 #include "sysdep/ptrace.h"
 
+/* Copied from kernel.h */
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
 #define CATCH_EINTR(expr) while ((errno = 0, ((expr) < 0)) && (errno == EINTR))
 
 extern int mode_tt;
@@ -31,7 +34,7 @@ extern unsigned long uml_physmem;
 extern unsigned long uml_reserved;
 extern unsigned long end_vm;
 extern unsigned long start_vm;
-extern unsigned long highmem;
+extern unsigned long long highmem;
 
 extern char host_info[];
 
@@ -52,7 +55,8 @@ extern int get_pty(void);
 extern void *um_kmalloc(int size);
 extern int switcheroo(int fd, int prot, void *from, void *to, int size);
 extern void do_exec(int old_pid, int new_pid);
-extern void tracer_panic(char *msg, ...);
+extern void tracer_panic(char *msg, ...)
+	__attribute__ ((format (printf, 1, 2)));
 extern int detach(int pid, int sig);
 extern int attach(int pid);
 extern void kill_child_dead(int pid);
diff --git a/arch/um/kernel/exec_kern.c b/arch/um/kernel/exec_kern.c
index 1ca84319317..c0cb627bf59 100644
--- a/arch/um/kernel/exec_kern.c
+++ b/arch/um/kernel/exec_kern.c
@@ -22,6 +22,7 @@
 
 void flush_thread(void)
 {
+	arch_flush_thread(&current->thread.arch);
 	CHOOSE_MODE(flush_thread_tt(), flush_thread_skas());
 }
 
@@ -58,14 +59,14 @@ long um_execve(char *file, char __user *__user *argv, char __user *__user *env)
 	return(err);
 }
 
-long sys_execve(char *file, char __user *__user *argv,
+long sys_execve(char __user *file, char __user *__user *argv,
 		char __user *__user *env)
 {
 	long error;
 	char *filename;
 
 	lock_kernel();
-	filename = getname((char __user *) file);
+	filename = getname(file);
 	error = PTR_ERR(filename);
 	if (IS_ERR(filename)) goto out;
 	error = execve1(filename, argv, env);
@@ -74,14 +75,3 @@ long sys_execve(char *file, char __user *__user *argv,
 	unlock_kernel();
 	return(error);
 }
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
diff --git a/arch/um/kernel/ksyms.c b/arch/um/kernel/ksyms.c
index 7713e7a6f47..432cf0b97a1 100644
--- a/arch/um/kernel/ksyms.c
+++ b/arch/um/kernel/ksyms.c
@@ -39,7 +39,6 @@ EXPORT_SYMBOL(um_virt_to_phys);
 EXPORT_SYMBOL(mode_tt);
 EXPORT_SYMBOL(handle_page_fault);
 EXPORT_SYMBOL(find_iomem);
-EXPORT_SYMBOL(end_iomem);
 
 #ifdef CONFIG_MODE_TT
 EXPORT_SYMBOL(strncpy_from_user_tt);
@@ -89,12 +88,10 @@ EXPORT_SYMBOL(dump_thread);
 EXPORT_SYMBOL(do_gettimeofday);
 EXPORT_SYMBOL(do_settimeofday);
 
-/* This is here because UML expands open to sys_open, not to a system
+/* This is here because UML expands lseek to sys_lseek, not to a system
  * call instruction.
  */
-EXPORT_SYMBOL(sys_open);
 EXPORT_SYMBOL(sys_lseek);
-EXPORT_SYMBOL(sys_read);
 EXPORT_SYMBOL(sys_wait4);
 
 #ifdef CONFIG_SMP
diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index 92cce96b5e2..44e41a35f00 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -30,7 +30,7 @@ extern char __binary_start;
 unsigned long *empty_zero_page = NULL;
 unsigned long *empty_bad_page = NULL;
 pgd_t swapper_pg_dir[PTRS_PER_PGD];
-unsigned long highmem;
+unsigned long long highmem;
 int kmalloc_ok = 0;
 
 static unsigned long brk_end;
diff --git a/arch/um/kernel/process_kern.c b/arch/um/kernel/process_kern.c
index 3113cab8675..f6a5a502120 100644
--- a/arch/um/kernel/process_kern.c
+++ b/arch/um/kernel/process_kern.c
@@ -156,9 +156,25 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long sp,
 		unsigned long stack_top, struct task_struct * p, 
 		struct pt_regs *regs)
 {
+	int ret;
+
 	p->thread = (struct thread_struct) INIT_THREAD;
-	return(CHOOSE_MODE_PROC(copy_thread_tt, copy_thread_skas, nr, 
-				clone_flags, sp, stack_top, p, regs));
+	ret = CHOOSE_MODE_PROC(copy_thread_tt, copy_thread_skas, nr,
+				clone_flags, sp, stack_top, p, regs);
+
+	if (ret || !current->thread.forking)
+		goto out;
+
+	clear_flushed_tls(p);
+
+	/*
+	 * Set a new TLS for the child thread?
+	 */
+	if (clone_flags & CLONE_SETTLS)
+		ret = arch_copy_tls(p);
+
+out:
+	return ret;
 }
 
 void initial_thread_cb(void (*proc)(void *), void *arg)
@@ -185,10 +201,6 @@ void default_idle(void)
 {
 	CHOOSE_MODE(uml_idle_timer(), (void) 0);
 
-	atomic_inc(&init_mm.mm_count);
-	current->mm = &init_mm;
-	current->active_mm = &init_mm;
-
 	while(1){
 		/* endless idle loop with no priority at all */
 
@@ -407,7 +419,7 @@ static int proc_read_sysemu(char *buf, char **start, off_t offset, int size,int
 	return strlen(buf);
 }
 
-static int proc_write_sysemu(struct file *file,const char *buf, unsigned long count,void *data)
+static int proc_write_sysemu(struct file *file,const char __user *buf, unsigned long count,void *data)
 {
 	char tmp[2];
 
diff --git a/arch/um/kernel/ptrace.c b/arch/um/kernel/ptrace.c
index 98e09395c09..60d2eda995c 100644
--- a/arch/um/kernel/ptrace.c
+++ b/arch/um/kernel/ptrace.c
@@ -46,6 +46,7 @@ extern int poke_user(struct task_struct * child, long addr, long data);
 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 {
 	int i, ret;
+	unsigned long __user *p = (void __user *)(unsigned long)data;
 
 	switch (request) {
 		/* when I and D space are separate, these will need to be fixed. */
@@ -58,7 +59,7 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 		if (copied != sizeof(tmp))
 			break;
-		ret = put_user(tmp, (unsigned long __user *) data);
+		ret = put_user(tmp, p);
 		break;
 	}
 
@@ -136,15 +137,13 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 
 #ifdef PTRACE_GETREGS
 	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
-	  	if (!access_ok(VERIFY_WRITE, (unsigned long *)data, 
-			       MAX_REG_OFFSET)) {
+		if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
 			ret = -EIO;
 			break;
 		}
 		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__put_user(getreg(child, i),
-				   (unsigned long __user *) data);
-			data += sizeof(long);
+			__put_user(getreg(child, i), p);
+			p++;
 		}
 		ret = 0;
 		break;
@@ -153,15 +152,14 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 #ifdef PTRACE_SETREGS
 	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 		unsigned long tmp = 0;
-	  	if (!access_ok(VERIFY_READ, (unsigned *)data, 
-			       MAX_REG_OFFSET)) {
+		if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
 			ret = -EIO;
 			break;
 		}
 		for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
-			__get_user(tmp, (unsigned long __user *) data);
+			__get_user(tmp, p);
 			putreg(child, i, tmp);
-			data += sizeof(long);
+			p++;
 		}
 		ret = 0;
 		break;
@@ -187,14 +185,23 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 		ret = set_fpxregs(data, child);
 		break;
 #endif
+	case PTRACE_GET_THREAD_AREA:
+		ret = ptrace_get_thread_area(child, addr,
+					     (struct user_desc __user *) data);
+		break;
+
+	case PTRACE_SET_THREAD_AREA:
+		ret = ptrace_set_thread_area(child, addr,
+					     (struct user_desc __user *) data);
+		break;
+
 	case PTRACE_FAULTINFO: {
-                /* Take the info from thread->arch->faultinfo,
-                 * but transfer max. sizeof(struct ptrace_faultinfo).
-                 * On i386, ptrace_faultinfo is smaller!
-                 */
-                ret = copy_to_user((unsigned long __user *) data,
-                                   &child->thread.arch.faultinfo,
-                                   sizeof(struct ptrace_faultinfo));
+		/* Take the info from thread->arch->faultinfo,
+		 * but transfer max. sizeof(struct ptrace_faultinfo).
+		 * On i386, ptrace_faultinfo is smaller!
+		 */
+		ret = copy_to_user(p, &child->thread.arch.faultinfo,
+				   sizeof(struct ptrace_faultinfo));
 		if(ret)
 			break;
 		break;
@@ -204,8 +211,7 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
 	case PTRACE_LDT: {
 		struct ptrace_ldt ldt;
 
-		if(copy_from_user(&ldt, (unsigned long __user *) data,
-				  sizeof(ldt))){
+		if(copy_from_user(&ldt, p, sizeof(ldt))){
 			ret = -EIO;
 			break;
 		}
diff --git a/arch/um/kernel/skas/process_kern.c b/arch/um/kernel/skas/process_kern.c
index 3f70a2e12f0..2135eaf98a9 100644
--- a/arch/um/kernel/skas/process_kern.c
+++ b/arch/um/kernel/skas/process_kern.c
@@ -35,6 +35,8 @@ void switch_to_skas(void *prev, void *next)
 	switch_threads(&from->thread.mode.skas.switch_buf,
 		       to->thread.mode.skas.switch_buf);
 
+	arch_switch_to_skas(current->thread.prev_sched, current);
+
 	if(current->pid == 0)
 		switch_timers(1);
 }
@@ -89,10 +91,17 @@ void fork_handler(int sig)
 		panic("blech");
 
 	schedule_tail(current->thread.prev_sched);
+
+	/* XXX: if interrupt_end() calls schedule, this call to
+	 * arch_switch_to_skas isn't needed. We could want to apply this to
+	 * improve performance. -bb */
+	arch_switch_to_skas(current->thread.prev_sched, current);
+
 	current->thread.prev_sched = NULL;
 
 /* Handle any immediate reschedules or signals */
 	interrupt_end();
+
 	userspace(&current->thread.regs.regs);
 }
 
@@ -109,6 +118,8 @@ int copy_thread_skas(int nr, unsigned long clone_flags, unsigned long sp,
 		if(sp != 0) REGS_SP(p->thread.regs.regs.skas.regs) = sp;
 
 		handler = fork_handler;
+
+		arch_copy_thread(&current->thread.arch, &p->thread.arch);
 	}
 	else {
 		init_thread_registers(&p->thread.regs.regs);
diff --git a/arch/um/kernel/syscall_kern.c b/arch/um/kernel/syscall_kern.c
index 8e1a3501ff4..37d3978337d 100644
--- a/arch/um/kernel/syscall_kern.c
+++ b/arch/um/kernel/syscall_kern.c
@@ -104,7 +104,7 @@ long sys_pipe(unsigned long __user * fildes)
 }
 
 
-long sys_uname(struct old_utsname * name)
+long sys_uname(struct old_utsname __user * name)
 {
 	long err;
 	if (!name)
@@ -115,7 +115,7 @@ long sys_uname(struct old_utsname * name)
 	return err?-EFAULT:0;
 }
 
-long sys_olduname(struct oldold_utsname * name)
+long sys_olduname(struct oldold_utsname __user * name)
 {
 	long error;
 
diff --git a/arch/um/kernel/trap_kern.c b/arch/um/kernel/trap_kern.c
index d56046c2aba..02f6d4d8dc3 100644
--- a/arch/um/kernel/trap_kern.c
+++ b/arch/um/kernel/trap_kern.c
@@ -198,7 +198,7 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, void *sc)
 		si.si_signo = SIGBUS;
 		si.si_errno = 0;
 		si.si_code = BUS_ADRERR;
-		si.si_addr = (void *)address;
+		si.si_addr = (void __user *)address;
                 current->thread.arch.faultinfo = fi;
 		force_sig_info(SIGBUS, &si, current);
 	} else if (err == -ENOMEM) {
@@ -207,7 +207,7 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, void *sc)
 	} else {
 		BUG_ON(err != -EFAULT);
 		si.si_signo = SIGSEGV;
-		si.si_addr = (void *) address;
+		si.si_addr = (void __user *) address;
                 current->thread.arch.faultinfo = fi;
 		force_sig_info(SIGSEGV, &si, current);
 	}
@@ -220,8 +220,8 @@ void bad_segv(struct faultinfo fi, unsigned long ip)
 
 	si.si_signo = SIGSEGV;
 	si.si_code = SEGV_ACCERR;
-        si.si_addr = (void *) FAULT_ADDRESS(fi);
-        current->thread.arch.faultinfo = fi;
+	si.si_addr = (void __user *) FAULT_ADDRESS(fi);
+	current->thread.arch.faultinfo = fi;
 	force_sig_info(SIGSEGV, &si, current);
 }
 
diff --git a/arch/um/kernel/tt/process_kern.c b/arch/um/kernel/tt/process_kern.c
index 295c1ac817b..a9c1443fc54 100644
--- a/arch/um/kernel/tt/process_kern.c
+++ b/arch/um/kernel/tt/process_kern.c
@@ -51,6 +51,13 @@ void switch_to_tt(void *prev, void *next)
 
 	c = 0;
 
+	/* Notice that here we "up" the semaphore on which "to" is waiting, and
+	 * below (the read) we wait on this semaphore (which is implemented by
+	 * switch_pipe) and go sleeping. Thus, after that, we have resumed in
+	 * "to", and can't use any more the value of "from" (which is outdated),
+	 * nor the value in "to" (since it was the task which stole us the CPU,
+	 * which we don't care about). */
+
 	err = os_write_file(to->thread.mode.tt.switch_pipe[1], &c, sizeof(c));
 	if(err != sizeof(c))
 		panic("write of switch_pipe failed, err = %d", -err);
@@ -77,7 +84,7 @@ void switch_to_tt(void *prev, void *next)
 	change_sig(SIGALRM, alrm);
 	change_sig(SIGPROF, prof);
 
-	arch_switch();
+	arch_switch_to_tt(prev_sched, current);
 
 	flush_tlb_all();
 	local_irq_restore(flags);
@@ -141,7 +148,6 @@ static void new_thread_handler(int sig)
 	set_cmdline("(kernel thread)");
 
 	change_sig(SIGUSR1, 1);
-	change_sig(SIGVTALRM, 1);
 	change_sig(SIGPROF, 1);
 	local_irq_enable();
 	if(!run_kernel_thread(fn, arg, &current->thread.exec_buf))
diff --git a/arch/um/os-Linux/Makefile b/arch/um/os-Linux/Makefile
index 1659386b42b..f4bfc4c7cca 100644
--- a/arch/um/os-Linux/Makefile
+++ b/arch/um/os-Linux/Makefile
@@ -4,7 +4,7 @@
 #
 
 obj-y = aio.o elf_aux.o file.o helper.o irq.o main.o mem.o process.o sigio.o \
-	signal.o start_up.o time.o trap.o tt.o tty.o uaccess.o umid.o \
+	signal.o start_up.o time.o trap.o tt.o tty.o uaccess.o umid.o tls.o \
 	user_syms.o util.o drivers/ sys-$(SUBARCH)/
 
 obj-$(CONFIG_MODE_SKAS) += skas/
@@ -12,12 +12,9 @@ obj-$(CONFIG_TTY_LOG) += tty_log.o
 user-objs-$(CONFIG_TTY_LOG) += tty_log.o
 
 USER_OBJS := $(user-objs-y) aio.o elf_aux.o file.o helper.o irq.o main.o mem.o \
-	process.o sigio.o signal.o start_up.o time.o trap.o tt.o tty.o \
+	process.o sigio.o signal.o start_up.o time.o trap.o tt.o tty.o tls.o \
 	uaccess.o umid.o util.o
 
-elf_aux.o: $(ARCH_DIR)/kernel-offsets.h
-CFLAGS_elf_aux.o += -I$(objtree)/arch/um
-
 CFLAGS_user_syms.o += -DSUBARCH_$(SUBARCH)
 
 HAVE_AIO_ABI := $(shell [ -r /usr/include/linux/aio_abi.h ] && \
diff --git a/arch/um/os-Linux/drivers/ethertap_kern.c b/arch/um/os-Linux/drivers/ethertap_kern.c
index 6ae4b19d9f5..768606bec23 100644
--- a/arch/um/os-Linux/drivers/ethertap_kern.c
+++ b/arch/um/os-Linux/drivers/ethertap_kern.c
@@ -102,18 +102,7 @@ static struct transport ethertap_transport = {
 static int register_ethertap(void)
 {
 	register_transport(&ethertap_transport);
-	return(1);
+	return 0;
 }
 
 __initcall(register_ethertap);
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
diff --git a/arch/um/os-Linux/drivers/ethertap_user.c b/arch/um/os-Linux/drivers/ethertap_user.c
index 901b85e8a1c..8f49507e64e 100644
--- a/arch/um/os-Linux/drivers/ethertap_user.c
+++ b/arch/um/os-Linux/drivers/ethertap_user.c
@@ -40,7 +40,7 @@ static void etap_change(int op, unsigned char *addr, unsigned char *netmask,
 			int fd)
 {
 	struct addr_change change;
-	void *output;
+	char *output;
 	int n;
 
 	change.what = op;
diff --git a/arch/um/os-Linux/drivers/tuntap_kern.c b/arch/um/os-Linux/drivers/tuntap_kern.c
index 4202b9ebad4..190009a6f89 100644
--- a/arch/um/os-Linux/drivers/tuntap_kern.c
+++ b/arch/um/os-Linux/drivers/tuntap_kern.c
@@ -87,18 +87,7 @@ static struct transport tuntap_transport = {
 static int register_tuntap(void)
 {
 	register_transport(&tuntap_transport);
-	return(1);
+	return 0;
 }
 
 __initcall(register_tuntap);
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
index 6490a4ff40a..6987d1d247a 100644
--- a/arch/um/os-Linux/helper.c
+++ b/arch/um/os-Linux/helper.c
@@ -43,7 +43,7 @@ static int helper_child(void *arg)
 		(*data->pre_exec)(data->pre_data);
 	execvp(argv[0], argv);
 	errval = errno;
-	printk("execvp of '%s' failed - errno = %d\n", argv[0], errno);
+	printk("helper_child - execve of '%s' failed - errno = %d\n", argv[0], errno);
 	os_write_file(data->fd, &errval, sizeof(errval));
 	kill(os_getpid(), SIGKILL);
 	return(0);
@@ -92,15 +92,15 @@ int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv,
 	close(fds[1]);
 	fds[1] = -1;
 
-	/*Read the errno value from the child.*/
+	/* Read the errno value from the child, if the exec failed, or get 0 if
+	 * the exec succeeded because the pipe fd was set as close-on-exec. */
 	n = os_read_file(fds[0], &ret, sizeof(ret));
-	if(n < 0){
+	if (n < 0) {
 		printk("run_helper : read on pipe failed, ret = %d\n", -n);
 		ret = n;
 		kill(pid, SIGKILL);
 		CATCH_EINTR(waitpid(pid, NULL, 0));
-	}
-	else if(n != 0){
+	} else if(n != 0){
 		CATCH_EINTR(n = waitpid(pid, NULL, 0));
 		ret = -errno;
 	} else {
diff --git a/arch/um/os-Linux/mem.c b/arch/um/os-Linux/mem.c
index 9d7d69a523b..71bb90a7606 100644
--- a/arch/um/os-Linux/mem.c
+++ b/arch/um/os-Linux/mem.c
@@ -53,33 +53,36 @@ static void __init find_tempdir(void)
  */
 int make_tempfile(const char *template, char **out_tempname, int do_unlink)
 {
-	char tempname[MAXPATHLEN];
+	char *tempname;
 	int fd;
 
+	tempname = malloc(MAXPATHLEN);
+
 	find_tempdir();
-	if (*template != '/')
+	if (template[0] != '/')
 		strcpy(tempname, tempdir);
 	else
-		*tempname = 0;
+		tempname[0] = '\0';
 	strcat(tempname, template);
 	fd = mkstemp(tempname);
 	if(fd < 0){
 		fprintf(stderr, "open - cannot create %s: %s\n", tempname,
 			strerror(errno));
-		return -1;
+		goto out;
 	}
 	if(do_unlink && (unlink(tempname) < 0)){
 		perror("unlink");
-		return -1;
+		goto out;
 	}
 	if(out_tempname){
-		*out_tempname = strdup(tempname);
-		if(*out_tempname == NULL){
-			perror("strdup");
-			return -1;
-		}
+		*out_tempname = tempname;
+	} else {
+		free(tempname);
 	}
 	return(fd);
+out:
+	free(tempname);
+	return -1;
 }
 
 #define TEMPNAME_TEMPLATE "vm_file-XXXXXX"
@@ -121,36 +124,11 @@ int create_tmp_file(unsigned long long len)
 	return(fd);
 }
 
-static int create_anon_file(unsigned long long len)
-{
-	void *addr;
-	int fd;
-
-	fd = open("/dev/anon", O_RDWR);
-	if(fd < 0) {
-		perror("opening /dev/anon");
-		exit(1);
-	}
-
-	addr = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
-	if(addr == MAP_FAILED){
-		perror("mapping physmem file");
-		exit(1);
-	}
-	munmap(addr, len);
-
-	return(fd);
-}
-
-extern int have_devanon;
-
 int create_mem_file(unsigned long long len)
 {
 	int err, fd;
 
-	if(have_devanon)
-		fd = create_anon_file(len);
-	else fd = create_tmp_file(len);
+	fd = create_tmp_file(len);
 
 	err = os_set_exec_close(fd, 1);
 	if(err < 0){
diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c
index d261888f39c..8176b0b5204 100644
--- a/arch/um/os-Linux/process.c
+++ b/arch/um/os-Linux/process.c
@@ -11,6 +11,7 @@
 #include <linux/unistd.h>
 #include <sys/mman.h>
 #include <sys/wait.h>
+#include <sys/mman.h>
 #include "ptrace_user.h"
 #include "os.h"
 #include "user.h"
@@ -20,6 +21,7 @@
 #include "kern_util.h"
 #include "longjmp.h"
 #include "skas_ptrace.h"
+#include "kern_constants.h"
 
 #define ARBITRARY_ADDR -1
 #define FAILURE_PID    -1
@@ -187,6 +189,48 @@ int os_unmap_memory(void *addr, int len)
         return(0);
 }
 
+#ifndef MADV_REMOVE
+#define MADV_REMOVE	0x5		/* remove these pages & resources */
+#endif
+
+int os_drop_memory(void *addr, int length)
+{
+	int err;
+
+	err = madvise(addr, length, MADV_REMOVE);
+	if(err < 0)
+		err = -errno;
+	return err;
+}
+
+int can_drop_memory(void)
+{
+	void *addr;
+	int fd;
+
+	printk("Checking host MADV_REMOVE support...");
+	fd = create_mem_file(UM_KERN_PAGE_SIZE);
+	if(fd < 0){
+		printk("Creating test memory file failed, err = %d\n", -fd);
+		return 0;
+	}
+
+	addr = mmap64(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
+		      MAP_PRIVATE, fd, 0);
+	if(addr == MAP_FAILED){
+		printk("Mapping test memory file failed, err = %d\n", -errno);
+		return 0;
+	}
+
+	if(madvise(addr, UM_KERN_PAGE_SIZE, MADV_REMOVE) != 0){
+		printk("MADV_REMOVE failed, err = %d\n", -errno);
+		return 0;
+	}
+
+	printk("OK\n");
+	return 1;
+}
+
 void init_new_thread_stack(void *sig_stack, void (*usr1_handler)(int))
 {
 	int flags = 0, pages;
diff --git a/arch/um/os-Linux/sigio.c b/arch/um/os-Linux/sigio.c
index 9ba94294714..00e9388e947 100644
--- a/arch/um/os-Linux/sigio.c
+++ b/arch/um/os-Linux/sigio.c
@@ -304,8 +304,8 @@ out_clear_poll:
 					   .size	= 0,
 					   .used	= 0 });
 out_free:
-	kfree(p);
 	sigio_unlock();
+	kfree(p);
 out_close2:
 	close(l_sigio_private[0]);
 	close(l_sigio_private[1]);
diff --git a/arch/um/os-Linux/skas/mem.c b/arch/um/os-Linux/skas/mem.c
index fbb080c2fc2..b3c11cfa995 100644
--- a/arch/um/os-Linux/skas/mem.c
+++ b/arch/um/os-Linux/skas/mem.c
@@ -82,8 +82,8 @@ static inline long do_syscall_stub(struct mm_id * mm_idp, void **addr)
 	if (offset) {
 		data = (unsigned long *)(mm_idp->stack +
 					 offset - UML_CONFIG_STUB_DATA);
-		printk("do_syscall_stub : ret = %d, offset = %d, "
-		       "data = 0x%x\n", ret, offset, data);
+		printk("do_syscall_stub : ret = %ld, offset = %ld, "
+		       "data = %p\n", ret, offset, data);
 		syscall = (unsigned long *)((unsigned long)data + data[0]);
 		printk("do_syscall_stub: syscall %ld failed, return value = "
 		       "0x%lx, expected return value = 0x%lx\n",
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index bbf34cb91ce..045ae003745 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -265,7 +265,7 @@ void userspace(union uml_pt_regs *regs)
 		if(err)
 			panic("userspace - could not resume userspace process, "
 			      "pid=%d, ptrace operation = %d, errno = %d\n",
-			      op, errno);
+			      pid, op, errno);
 
 		CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
 		if(err < 0)
@@ -369,7 +369,7 @@ int copy_context_skas0(unsigned long new_stack, int pid)
 	 */
 	wait_stub_done(pid, -1, "copy_context_skas0");
 	if (child_data->err != UML_CONFIG_STUB_DATA)
-		panic("copy_context_skas0 - stub-child reports error %d\n",
+		panic("copy_context_skas0 - stub-child reports error %ld\n",
 		      child_data->err);
 
 	if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c
index 32753131f8d..387e26af301 100644
--- a/arch/um/os-Linux/start_up.c
+++ b/arch/um/os-Linux/start_up.c
@@ -470,25 +470,6 @@ int can_do_skas(void)
 }
 #endif
 
-int have_devanon = 0;
-
-/* Runs on boot kernel stack - already safe to use printk. */
-
-void check_devanon(void)
-{
-	int fd;
-
-	printk("Checking for /dev/anon on the host...");
-	fd = open("/dev/anon", O_RDWR);
-	if(fd < 0){
-		printk("Not available (open failed with errno %d)\n", errno);
-		return;
-	}
-
-	printk("OK\n");
-	have_devanon = 1;
-}
-
 int __init parse_iomem(char *str, int *add)
 {
 	struct iomem_region *new;
@@ -664,6 +645,5 @@ void os_check_bugs(void)
 {
 	check_ptrace();
 	check_sigio();
-	check_devanon();
 }
 
diff --git a/arch/um/os-Linux/sys-i386/Makefile b/arch/um/os-Linux/sys-i386/Makefile
index 340ef26f594..b3213613c41 100644
--- a/arch/um/os-Linux/sys-i386/Makefile
+++ b/arch/um/os-Linux/sys-i386/Makefile
@@ -3,7 +3,7 @@
 # Licensed under the GPL
 #
 
-obj-$(CONFIG_MODE_SKAS) = registers.o
+obj-$(CONFIG_MODE_SKAS) = registers.o tls.o
 
 USER_OBJS := $(obj-y)
 
diff --git a/arch/um/os-Linux/sys-i386/tls.c b/arch/um/os-Linux/sys-i386/tls.c
new file mode 100644
index 00000000000..120abbe4e3c
--- /dev/null
+++ b/arch/um/os-Linux/sys-i386/tls.c
@@ -0,0 +1,34 @@
+#include <errno.h>
+#include <linux/unistd.h>
+#include "sysdep/tls.h"
+#include "user_util.h"
+
+static _syscall1(int, get_thread_area, user_desc_t *, u_info);
+
+/* Checks whether host supports TLS, and sets *tls_min according to the value
+ * valid on the host.
+ * i386 host have it == 6; x86_64 host have it == 12, for i386 emulation. */
+void check_host_supports_tls(int *supports_tls, int *tls_min) {
+	/* Values for x86 and x86_64.*/
+	int val[] = {GDT_ENTRY_TLS_MIN_I386, GDT_ENTRY_TLS_MIN_X86_64};
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(val); i++) {
+		user_desc_t info;
+		info.entry_number = val[i];
+
+		if (get_thread_area(&info) == 0) {
+			*tls_min = val[i];
+			*supports_tls = 1;
+			return;
+		} else {
+			if (errno == EINVAL)
+				continue;
+			else if (errno == ENOSYS)
+				*supports_tls = 0;
+				return;
+		}
+	}
+
+	*supports_tls = 0;
+}
diff --git a/arch/um/os-Linux/tls.c b/arch/um/os-Linux/tls.c
new file mode 100644
index 00000000000..9cb09a45546
--- /dev/null
+++ b/arch/um/os-Linux/tls.c
@@ -0,0 +1,76 @@
+#include <errno.h>
+#include <sys/ptrace.h>
+#include <asm/ldt.h>
+#include "sysdep/tls.h"
+#include "uml-config.h"
+
+/* TLS support - we basically rely on the host's one.*/
+
+/* In TT mode, this should be called only by the tracing thread, and makes sense
+ * only for PTRACE_SET_THREAD_AREA. In SKAS mode, it's used normally.
+ *
+ */
+
+#ifndef PTRACE_GET_THREAD_AREA
+#define PTRACE_GET_THREAD_AREA 25
+#endif
+
+#ifndef PTRACE_SET_THREAD_AREA
+#define PTRACE_SET_THREAD_AREA 26
+#endif
+
+int os_set_thread_area(user_desc_t *info, int pid)
+{
+	int ret;
+
+	ret = ptrace(PTRACE_SET_THREAD_AREA, pid, info->entry_number,
+		     (unsigned long) info);
+	if (ret < 0)
+		ret = -errno;
+	return ret;
+}
+
+#ifdef UML_CONFIG_MODE_SKAS
+
+int os_get_thread_area(user_desc_t *info, int pid)
+{
+	int ret;
+
+	ret = ptrace(PTRACE_GET_THREAD_AREA, pid, info->entry_number,
+		     (unsigned long) info);
+	if (ret < 0)
+		ret = -errno;
+	return ret;
+}
+
+#endif
+
+#ifdef UML_CONFIG_MODE_TT
+#include "linux/unistd.h"
+
+static _syscall1(int, get_thread_area, user_desc_t *, u_info);
+static _syscall1(int, set_thread_area, user_desc_t *, u_info);
+
+int do_set_thread_area_tt(user_desc_t *info)
+{
+	int ret;
+
+	ret = set_thread_area(info);
+	if (ret < 0) {
+		ret = -errno;
+	}
+	return ret;
+}
+
+int do_get_thread_area_tt(user_desc_t *info)
+{
+	int ret;
+
+	ret = get_thread_area(info);
+	if (ret < 0) {
+		ret = -errno;
+	}
+	return ret;
+}
+
+#endif /* UML_CONFIG_MODE_TT */
diff --git a/arch/um/os-Linux/umid.c b/arch/um/os-Linux/umid.c
index 198e5916328..34bfc1bb9e3 100644
--- a/arch/um/os-Linux/umid.c
+++ b/arch/um/os-Linux/umid.c
@@ -120,7 +120,8 @@ static int not_dead_yet(char *dir)
 
 	dead = 0;
 	fd = open(file, O_RDONLY);
-	if(fd < 0){
+	if(fd < 0) {
+		fd = -errno;
 		if(fd != -ENOENT){
 			printk("not_dead_yet : couldn't open pid file '%s', "
 			       "err = %d\n", file, -fd);
@@ -130,9 +131,13 @@ static int not_dead_yet(char *dir)
 
 	err = 0;
 	n = read(fd, pid, sizeof(pid));
-	if(n <= 0){
+	if(n < 0){
+		printk("not_dead_yet : couldn't read pid file '%s', "
+		       "err = %d\n", file, errno);
+		goto out_close;
+	} else if(n == 0){
 		printk("not_dead_yet : couldn't read pid file '%s', "
-		       "err = %d\n", file, -n);
+		       "0-byte read\n", file);
 		goto out_close;
 	}
 
@@ -155,9 +160,9 @@ static int not_dead_yet(char *dir)
 
 	return err;
 
- out_close:
+out_close:
 	close(fd);
- out:
+out:
 	return 0;
 }
 
diff --git a/arch/um/os-Linux/user_syms.c b/arch/um/os-Linux/user_syms.c
index 8da6ab31152..2598158e1f5 100644
--- a/arch/um/os-Linux/user_syms.c
+++ b/arch/um/os-Linux/user_syms.c
@@ -18,14 +18,19 @@ extern void *memmove(void *, const void *, size_t);
 extern void *memset(void *, int, size_t);
 extern int printf(const char *, ...);
 
+/* If they're not defined, the export is included in lib/string.c.*/
+#ifdef __HAVE_ARCH_STRLEN
 EXPORT_SYMBOL(strlen);
+#endif
+#ifdef __HAVE_ARCH_STRSTR
+EXPORT_SYMBOL(strstr);
+#endif
+
 EXPORT_SYMBOL(memcpy);
 EXPORT_SYMBOL(memmove);
 EXPORT_SYMBOL(memset);
 EXPORT_SYMBOL(printf);
 
-EXPORT_SYMBOL(strstr);
-
 /* Here, instead, I can provide a fake prototype. Yes, someone cares: genksyms.
  * However, the modules will use the CRC defined *here*, no matter if it is
  * good; so the versions of these symbols will always match
diff --git a/arch/um/scripts/Makefile.rules b/arch/um/scripts/Makefile.rules
index 2e41cabd3d9..5e7a9c310aa 100644
--- a/arch/um/scripts/Makefile.rules
+++ b/arch/um/scripts/Makefile.rules
@@ -9,10 +9,8 @@ USER_OBJS := $(foreach file,$(USER_OBJS),$(obj)/$(file))
 
 $(USER_OBJS) $(USER_OBJS:.o=.i) $(USER_OBJS:.o=.s) $(USER_OBJS:.o=.lst): \
 	c_flags = -Wp,-MD,$(depfile) $(USER_CFLAGS) $(CFLAGS_$(notdir $@))
-$(USER_OBJS): cmd_checksrc =
-$(USER_OBJS): quiet_cmd_checksrc =
-$(USER_OBJS): cmd_force_checksrc =
-$(USER_OBJS): quiet_cmd_force_checksrc =
+$(USER_OBJS) : CHECKFLAGS := -D__linux__ -Dlinux -D__STDC__ \
+	-Dunix -D__unix__ -D__$(SUBARCH)__
 
 
 # The stubs and unmap.o can't try to call mcount or update basic block data
@@ -20,25 +18,7 @@ define unprofile
 	$(patsubst -pg,,$(patsubst -fprofile-arcs -ftest-coverage,,$(1)))
 endef
 
-
-# cmd_make_link checks to see if the $(foo-dir) variable starts with a /.  If
-# so, it's considered to be a path relative to $(srcdir) rather than
-# $(srcdir)/arch/$(SUBARCH).  This is because x86_64 wants to get ldt.c from
-# arch/um/sys-i386 rather than arch/i386 like the other borrowed files.  So,
-# it sets $(ldt.c-dir) to /arch/um/sys-i386.
-quiet_cmd_make_link = SYMLINK $@
-cmd_make_link       = rm -f $@; ln -sf $(srctree)$(if $(filter-out /%,$($(notdir $@)-dir)),/arch/$(SUBARCH))/$($(notdir $@)-dir)/$(notdir $@) $@
-
-# this needs to be before the foreach, because targets does not accept
-# complete paths like $(obj)/$(f). To make sure this works, use a := assignment
-# or we will get $(obj)/$(f) in the "targets" value.
-# Also, this forces you to use the := syntax when assigning to targets.
-# Otherwise the line below will cause an infinite loop (if you don't know why,
-# just do it).
-
-targets := $(targets) $(SYMLINKS)
-
-SYMLINKS := $(foreach f,$(SYMLINKS),$(obj)/$(f))
-
-$(SYMLINKS): FORCE
-	$(call if_changed,make_link)
+ifdef subarch-obj-y
+obj-y += subarch.o
+subarch-y = $(addprefix ../../$(SUBARCH)/,$(subarch-obj-y))
+endif
diff --git a/arch/um/scripts/Makefile.unmap b/arch/um/scripts/Makefile.unmap
deleted file mode 100644
index b2165188d94..00000000000
--- a/arch/um/scripts/Makefile.unmap
+++ /dev/null
@@ -1,22 +0,0 @@
-clean-files += unmap_tmp.o unmap_fin.o unmap.o
-
-ifdef CONFIG_MODE_TT
-
-#Always build unmap_fin.o
-extra-y += unmap_fin.o
-#Do dependency tracking for unmap.o (it will be always built, but won't get the tracking unless we use this).
-targets += unmap.o
-
-#XXX: partially copied from arch/um/scripts/Makefile.rules
-$(obj)/unmap.o: _c_flags = $(call unprofile,$(CFLAGS))
-
-quiet_cmd_wrapld = LD      $@
-define cmd_wrapld
-	$(LD) $(LDFLAGS) -r -o $(obj)/unmap_tmp.o $< ; \
-	$(OBJCOPY) $(UML_OBJCOPYFLAGS) $(obj)/unmap_tmp.o $@ -G switcheroo
-endef
-
-$(obj)/unmap_fin.o : $(obj)/unmap.o FORCE
-	$(call if_changed,wrapld)
-
-endif
diff --git a/arch/um/sys-i386/Makefile b/arch/um/sys-i386/Makefile
index f5fd5b0156d..98b20b7bba4 100644
--- a/arch/um/sys-i386/Makefile
+++ b/arch/um/sys-i386/Makefile
@@ -1,23 +1,18 @@
-obj-y := bitops.o bugs.o checksum.o delay.o fault.o ksyms.o ldt.o ptrace.o \
-	ptrace_user.o semaphore.o signal.o sigcontext.o syscalls.o sysrq.o \
-	sys_call_table.o
+obj-y = bugs.o checksum.o delay.o fault.o ksyms.o ldt.o ptrace.o \
+	ptrace_user.o signal.o sigcontext.o syscalls.o sysrq.o \
+	sys_call_table.o tls.o
 
 obj-$(CONFIG_MODE_SKAS) += stub.o stub_segv.o
 
-obj-$(CONFIG_HIGHMEM) += highmem.o
-obj-$(CONFIG_MODULES) += module.o
+subarch-obj-y = lib/bitops.o kernel/semaphore.o
+subarch-obj-$(CONFIG_HIGHMEM) += mm/highmem.o
+subarch-obj-$(CONFIG_MODULES) += kernel/module.o
 
 USER_OBJS := bugs.o ptrace_user.o sigcontext.o fault.o stub_segv.o
 
-SYMLINKS = bitops.c semaphore.c highmem.c module.c
-
 include arch/um/scripts/Makefile.rules
 
-bitops.c-dir = lib
-semaphore.c-dir = kernel
-highmem.c-dir = mm
-module.c-dir = kernel
-
-$(obj)/stub_segv.o : _c_flags = $(call unprofile,$(CFLAGS))
+extra-$(CONFIG_MODE_TT) += unmap.o
 
-include arch/um/scripts/Makefile.unmap
+$(obj)/stub_segv.o $(obj)/unmap.o: \
+	_c_flags = $(call unprofile,$(CFLAGS))
diff --git a/arch/um/sys-i386/ksyms.c b/arch/um/sys-i386/ksyms.c
index db524ab3f74..2a1eac1859c 100644
--- a/arch/um/sys-i386/ksyms.c
+++ b/arch/um/sys-i386/ksyms.c
@@ -15,7 +15,3 @@ EXPORT_SYMBOL(__up_wakeup);
 
 /* Networking helper routines. */
 EXPORT_SYMBOL(csum_partial);
-
-/* delay core functions */
-EXPORT_SYMBOL(__const_udelay);
-EXPORT_SYMBOL(__udelay);
diff --git a/arch/um/sys-i386/ptrace.c b/arch/um/sys-i386/ptrace.c
index 8032a105949..6028bc7cc01 100644
--- a/arch/um/sys-i386/ptrace.c
+++ b/arch/um/sys-i386/ptrace.c
@@ -15,9 +15,22 @@
 #include "sysdep/sigcontext.h"
 #include "sysdep/sc.h"
 
-void arch_switch(void)
+void arch_switch_to_tt(struct task_struct *from, struct task_struct *to)
 {
-	update_debugregs(current->thread.arch.debugregs_seq);
+	update_debugregs(to->thread.arch.debugregs_seq);
+	arch_switch_tls_tt(from, to);
+}
+
+void arch_switch_to_skas(struct task_struct *from, struct task_struct *to)
+{
+	int err = arch_switch_tls_skas(from, to);
+	if (!err)
+		return;
+
+	if (err != -EINVAL)
+		printk(KERN_WARNING "arch_switch_tls_skas failed, errno %d, not EINVAL\n", -err);
+	else
+		printk(KERN_WARNING "arch_switch_tls_skas failed, errno = EINVAL\n");
 }
 
 int is_syscall(unsigned long addr)
@@ -124,22 +137,22 @@ unsigned long getreg(struct task_struct *child, int regno)
 int peek_user(struct task_struct *child, long addr, long data)
 {
 /* read the word at location addr in the USER area. */
-        unsigned long tmp;
+	unsigned long tmp;
 
-        if ((addr & 3) || addr < 0)
-                return -EIO;
+	if ((addr & 3) || addr < 0)
+		return -EIO;
 
-        tmp = 0;  /* Default return condition */
-        if(addr < MAX_REG_OFFSET){
-                tmp = getreg(child, addr);
-        }
-        else if((addr >= offsetof(struct user, u_debugreg[0])) &&
-                (addr <= offsetof(struct user, u_debugreg[7]))){
-                addr -= offsetof(struct user, u_debugreg[0]);
-                addr = addr >> 2;
-                tmp = child->thread.arch.debugregs[addr];
-        }
-        return put_user(tmp, (unsigned long *) data);
+	tmp = 0;  /* Default return condition */
+	if(addr < MAX_REG_OFFSET){
+		tmp = getreg(child, addr);
+	}
+	else if((addr >= offsetof(struct user, u_debugreg[0])) &&
+		(addr <= offsetof(struct user, u_debugreg[7]))){
+		addr -= offsetof(struct user, u_debugreg[0]);
+		addr = addr >> 2;
+		tmp = child->thread.arch.debugregs[addr];
+	}
+	return put_user(tmp, (unsigned long __user *) data);
 }
 
 struct i387_fxsave_struct {
diff --git a/arch/um/sys-i386/ptrace_user.c b/arch/um/sys-i386/ptrace_user.c
index 7c376c95de5..40aa8853144 100644
--- a/arch/um/sys-i386/ptrace_user.c
+++ b/arch/um/sys-i386/ptrace_user.c
@@ -14,6 +14,7 @@
 #include "sysdep/thread.h"
 #include "user.h"
 #include "os.h"
+#include "uml-config.h"
 
 int ptrace_getregs(long pid, unsigned long *regs_out)
 {
@@ -43,6 +44,7 @@ int ptrace_setfpregs(long pid, unsigned long *regs)
 	return 0;
 }
 
+/* All the below stuff is of interest for TT mode only */
 static void write_debugregs(int pid, unsigned long *regs)
 {
 	struct user *dummy;
@@ -55,7 +57,7 @@ static void write_debugregs(int pid, unsigned long *regs)
 		if(ptrace(PTRACE_POKEUSR, pid, &dummy->u_debugreg[i],
 			  regs[i]) < 0)
 			printk("write_debugregs - ptrace failed on "
-			       "register %d, value = 0x%x, errno = %d\n", i,
+			       "register %d, value = 0x%lx, errno = %d\n", i,
 			       regs[i], errno);
 	}
 }
@@ -75,7 +77,6 @@ static void read_debugregs(int pid, unsigned long *regs)
 
 /* Accessed only by the tracing thread */
 static unsigned long kernel_debugregs[8] = { [ 0 ... 7 ] = 0 };
-static int debugregs_seq = 0;
 
 void arch_enter_kernel(void *task, int pid)
 {
@@ -89,6 +90,11 @@ void arch_leave_kernel(void *task, int pid)
 	write_debugregs(pid, TASK_DEBUGREGS(task));
 }
 
+#ifdef UML_CONFIG_PT_PROXY
+/* Accessed only by the tracing thread */
+static int debugregs_seq;
+
+/* Only called by the ptrace proxy */
 void ptrace_pokeuser(unsigned long addr, unsigned long data)
 {
 	if((addr < offsetof(struct user, u_debugreg[0])) ||
@@ -109,6 +115,7 @@ static void update_debugregs_cb(void *arg)
 	write_debugregs(pid, kernel_debugregs);
 }
 
+/* Optimized out in its header when not defined */
 void update_debugregs(int seq)
 {
 	int me;
@@ -118,6 +125,7 @@ void update_debugregs(int seq)
 	me = os_getpid();
 	initial_thread_cb(update_debugregs_cb, &me);
 }
+#endif
 
 /*
  * Overrides for Emacs so that we follow Linus's tabbing style.
diff --git a/arch/um/sys-i386/signal.c b/arch/um/sys-i386/signal.c
index 33a40f5ef0d..618fd859464 100644
--- a/arch/um/sys-i386/signal.c
+++ b/arch/um/sys-i386/signal.c
@@ -19,7 +19,7 @@
 #include "skas.h"
 
 static int copy_sc_from_user_skas(struct pt_regs *regs,
-				  struct sigcontext *from)
+				  struct sigcontext __user *from)
 {
   	struct sigcontext sc;
 	unsigned long fpregs[HOST_FP_SIZE];
@@ -57,7 +57,7 @@ static int copy_sc_from_user_skas(struct pt_regs *regs,
 	return(0);
 }
 
-int copy_sc_to_user_skas(struct sigcontext *to, struct _fpstate *to_fp,
+int copy_sc_to_user_skas(struct sigcontext *to, struct _fpstate __user *to_fp,
                          struct pt_regs *regs, unsigned long sp)
 {
   	struct sigcontext sc;
@@ -92,7 +92,7 @@ int copy_sc_to_user_skas(struct sigcontext *to, struct _fpstate *to_fp,
 		       "errno = %d\n", err);
 		return(1);
 	}
-	to_fp = (to_fp ? to_fp : (struct _fpstate *) (to + 1));
+	to_fp = (to_fp ? to_fp : (struct _fpstate __user *) (to + 1));
 	sc.fpstate = to_fp;
 
 	if(err)
@@ -113,10 +113,11 @@ int copy_sc_to_user_skas(struct sigcontext *to, struct _fpstate *to_fp,
  * saved pointer is in the kernel, but the sigcontext is in userspace, so we
  * copy_to_user it.
  */
-int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext *from,
+int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext __user *from,
 			 int fpsize)
 {
-	struct _fpstate *to_fp, *from_fp;
+	struct _fpstate *to_fp;
+	struct _fpstate __user *from_fp;
 	unsigned long sigs;
 	int err;
 
@@ -131,13 +132,14 @@ int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext *from,
 	return(err);
 }
 
-int copy_sc_to_user_tt(struct sigcontext *to, struct _fpstate *fp,
+int copy_sc_to_user_tt(struct sigcontext *to, struct _fpstate __user *fp,
 		       struct sigcontext *from, int fpsize, unsigned long sp)
 {
-	struct _fpstate *to_fp, *from_fp;
+	struct _fpstate __user *to_fp;
+	struct _fpstate *from_fp;
 	int err;
 
-	to_fp =	(fp ? fp : (struct _fpstate *) (to + 1));
+	to_fp =	(fp ? fp : (struct _fpstate __user *) (to + 1));
 	from_fp = from->fpstate;
 	err = copy_to_user(to, from, sizeof(*to));
 
@@ -145,7 +147,7 @@ int copy_sc_to_user_tt(struct sigcontext *to, struct _fpstate *fp,
 	 * delivery.  The sp passed in is the original, and this needs
 	 * to be restored, so we stick it in separately.
 	 */
-	err |= copy_to_user(&SC_SP(to), sp, sizeof(sp));
+	err |= copy_to_user(&SC_SP(to), &sp, sizeof(sp));
 
 	if(from_fp != NULL){
 		err |= copy_to_user(&to->fpstate, &to_fp, sizeof(to->fpstate));
@@ -165,7 +167,7 @@ static int copy_sc_from_user(struct pt_regs *to, void __user *from)
 	return(ret);
 }
 
-static int copy_sc_to_user(struct sigcontext *to, struct _fpstate *fp,
+static int copy_sc_to_user(struct sigcontext *to, struct _fpstate __user *fp,
 			   struct pt_regs *from, unsigned long sp)
 {
 	return(CHOOSE_MODE(copy_sc_to_user_tt(to, fp, UPT_SC(&from->regs),
@@ -173,7 +175,7 @@ static int copy_sc_to_user(struct sigcontext *to, struct _fpstate *fp,
                            copy_sc_to_user_skas(to, fp, from, sp)));
 }
 
-static int copy_ucontext_to_user(struct ucontext *uc, struct _fpstate *fp,
+static int copy_ucontext_to_user(struct ucontext __user *uc, struct _fpstate __user *fp,
 				 sigset_t *set, unsigned long sp)
 {
 	int err = 0;
@@ -188,7 +190,7 @@ static int copy_ucontext_to_user(struct ucontext *uc, struct _fpstate *fp,
 
 struct sigframe
 {
-	char *pretcode;
+	char __user *pretcode;
 	int sig;
 	struct sigcontext sc;
 	struct _fpstate fpstate;
@@ -198,10 +200,10 @@ struct sigframe
 
 struct rt_sigframe
 {
-	char *pretcode;
+	char __user *pretcode;
 	int sig;
-	struct siginfo *pinfo;
-	void *puc;
+	struct siginfo __user *pinfo;
+	void __user *puc;
 	struct siginfo info;
 	struct ucontext uc;
 	struct _fpstate fpstate;
@@ -213,16 +215,16 @@ int setup_signal_stack_sc(unsigned long stack_top, int sig,
 			  sigset_t *mask)
 {
 	struct sigframe __user *frame;
-	void *restorer;
+	void __user *restorer;
 	unsigned long save_sp = PT_REGS_SP(regs);
 	int err = 0;
 
 	stack_top &= -8UL;
-	frame = (struct sigframe *) stack_top - 1;
+	frame = (struct sigframe __user *) stack_top - 1;
 	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 		return 1;
 
-	restorer = (void *) frame->retcode;
+	restorer = frame->retcode;
 	if(ka->sa.sa_flags & SA_RESTORER)
 		restorer = ka->sa.sa_restorer;
 
@@ -278,16 +280,16 @@ int setup_signal_stack_si(unsigned long stack_top, int sig,
 			  siginfo_t *info, sigset_t *mask)
 {
 	struct rt_sigframe __user *frame;
-	void *restorer;
+	void __user *restorer;
 	unsigned long save_sp = PT_REGS_SP(regs);
 	int err = 0;
 
 	stack_top &= -8UL;
-	frame = (struct rt_sigframe *) stack_top - 1;
+	frame = (struct rt_sigframe __user *) stack_top - 1;
 	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 		return 1;
 
-	restorer = (void *) frame->retcode;
+	restorer = frame->retcode;
 	if(ka->sa.sa_flags & SA_RESTORER)
 		restorer = ka->sa.sa_restorer;
 
@@ -333,7 +335,7 @@ err:
 long sys_sigreturn(struct pt_regs regs)
 {
 	unsigned long sp = PT_REGS_SP(&current->thread.regs);
-	struct sigframe __user *frame = (struct sigframe *)(sp - 8);
+	struct sigframe __user *frame = (struct sigframe __user *)(sp - 8);
 	sigset_t set;
 	struct sigcontext __user *sc = &frame->sc;
 	unsigned long __user *oldmask = &sc->oldmask;
@@ -365,8 +367,8 @@ long sys_sigreturn(struct pt_regs regs)
 
 long sys_rt_sigreturn(struct pt_regs regs)
 {
-	unsigned long __user sp = PT_REGS_SP(&current->thread.regs);
-	struct rt_sigframe __user *frame = (struct rt_sigframe *) (sp - 4);
+	unsigned long sp = PT_REGS_SP(&current->thread.regs);
+	struct rt_sigframe __user *frame = (struct rt_sigframe __user *) (sp - 4);
 	sigset_t set;
 	struct ucontext __user *uc = &frame->uc;
 	int sig_size = _NSIG_WORDS * sizeof(unsigned long);
diff --git a/arch/um/sys-i386/sys_call_table.S b/arch/um/sys-i386/sys_call_table.S
index ad75c27afe3..1ff61474b25 100644
--- a/arch/um/sys-i386/sys_call_table.S
+++ b/arch/um/sys-i386/sys_call_table.S
@@ -6,8 +6,6 @@
 
 #define sys_vm86old sys_ni_syscall
 #define sys_vm86 sys_ni_syscall
-#define sys_set_thread_area sys_ni_syscall
-#define sys_get_thread_area sys_ni_syscall
 
 #define sys_stime um_stime
 #define sys_time um_time
diff --git a/arch/um/sys-i386/syscalls.c b/arch/um/sys-i386/syscalls.c
index 83e9be820a8..749dd1bfe60 100644
--- a/arch/um/sys-i386/syscalls.c
+++ b/arch/um/sys-i386/syscalls.c
@@ -61,21 +61,27 @@ long old_select(struct sel_arg_struct __user *arg)
 	return sys_select(a.n, a.inp, a.outp, a.exp, a.tvp);
 }
 
-/* The i386 version skips reading from %esi, the fourth argument. So we must do
- * this, too.
+/*
+ * The prototype on i386 is:
+ *
+ *     int clone(int flags, void * child_stack, int * parent_tidptr, struct user_desc * newtls, int * child_tidptr)
+ *
+ * and the "newtls" arg. on i386 is read by copy_thread directly from the
+ * register saved on the stack.
  */
 long sys_clone(unsigned long clone_flags, unsigned long newsp,
-	       int __user *parent_tid, int unused, int __user *child_tid)
+	       int __user *parent_tid, void *newtls, int __user *child_tid)
 {
 	long ret;
 
 	if (!newsp)
 		newsp = UPT_SP(&current->thread.regs.regs);
+
 	current->thread.forking = 1;
 	ret = do_fork(clone_flags, newsp, &current->thread.regs, 0, parent_tid,
 		      child_tid);
 	current->thread.forking = 0;
-	return(ret);
+	return ret;
 }
 
 /*
@@ -104,7 +110,7 @@ long sys_ipc (uint call, int first, int second,
 		union semun fourth;
 		if (!ptr)
 			return -EINVAL;
-		if (get_user(fourth.__pad, (void **) ptr))
+		if (get_user(fourth.__pad, (void __user * __user *) ptr))
 			return -EFAULT;
 		return sys_semctl (first, second, third, fourth);
 	}
diff --git a/arch/um/sys-i386/tls.c b/arch/um/sys-i386/tls.c
new file mode 100644
index 00000000000..71b9796258e
--- /dev/null
+++ b/arch/um/sys-i386/tls.c
@@ -0,0 +1,384 @@
+/*
+ * Copyright (C) 2005 Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
+ * Licensed under the GPL
+ */
+
+#include "linux/config.h"
+#include "linux/kernel.h"
+#include "linux/sched.h"
+#include "linux/slab.h"
+#include "linux/types.h"
+#include "asm/uaccess.h"
+#include "asm/ptrace.h"
+#include "asm/segment.h"
+#include "asm/smp.h"
+#include "asm/desc.h"
+#include "choose-mode.h"
+#include "kern.h"
+#include "kern_util.h"
+#include "mode_kern.h"
+#include "os.h"
+#include "mode.h"
+
+#ifdef CONFIG_MODE_SKAS
+#include "skas.h"
+#endif
+
+/* If needed we can detect when it's uninitialized. */
+static int host_supports_tls = -1;
+int host_gdt_entry_tls_min = -1;
+
+#ifdef CONFIG_MODE_SKAS
+int do_set_thread_area_skas(struct user_desc *info)
+{
+	int ret;
+	u32 cpu;
+
+	cpu = get_cpu();
+	ret = os_set_thread_area(info, userspace_pid[cpu]);
+	put_cpu();
+	return ret;
+}
+
+int do_get_thread_area_skas(struct user_desc *info)
+{
+	int ret;
+	u32 cpu;
+
+	cpu = get_cpu();
+	ret = os_get_thread_area(info, userspace_pid[cpu]);
+	put_cpu();
+	return ret;
+}
+#endif
+
+/*
+ * sys_get_thread_area: get a yet unused TLS descriptor index.
+ * XXX: Consider leaving one free slot for glibc usage at first place. This must
+ * be done here (and by changing GDT_ENTRY_TLS_* macros) and nowhere else.
+ *
+ * Also, this must be tested when compiling in SKAS mode with dinamic linking
+ * and running against NPTL.
+ */
+static int get_free_idx(struct task_struct* task)
+{
+	struct thread_struct *t = &task->thread;
+	int idx;
+
+	if (!t->arch.tls_array)
+		return GDT_ENTRY_TLS_MIN;
+
+	for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++)
+		if (!t->arch.tls_array[idx].present)
+			return idx + GDT_ENTRY_TLS_MIN;
+	return -ESRCH;
+}
+
+static inline void clear_user_desc(struct user_desc* info)
+{
+	/* Postcondition: LDT_empty(info) returns true. */
+	memset(info, 0, sizeof(*info));
+
+	/* Check the LDT_empty or the i386 sys_get_thread_area code - we obtain
+	 * indeed an empty user_desc.
+	 */
+	info->read_exec_only = 1;
+	info->seg_not_present = 1;
+}
+
+#define O_FORCE 1
+
+static int load_TLS(int flags, struct task_struct *to)
+{
+	int ret = 0;
+	int idx;
+
+	for (idx = GDT_ENTRY_TLS_MIN; idx < GDT_ENTRY_TLS_MAX; idx++) {
+		struct uml_tls_struct* curr = &to->thread.arch.tls_array[idx - GDT_ENTRY_TLS_MIN];
+
+		/* Actually, now if it wasn't flushed it gets cleared and
+		 * flushed to the host, which will clear it.*/
+		if (!curr->present) {
+			if (!curr->flushed) {
+				clear_user_desc(&curr->tls);
+				curr->tls.entry_number = idx;
+			} else {
+				WARN_ON(!LDT_empty(&curr->tls));
+				continue;
+			}
+		}
+
+		if (!(flags & O_FORCE) && curr->flushed)
+			continue;
+
+		ret = do_set_thread_area(&curr->tls);
+		if (ret)
+			goto out;
+
+		curr->flushed = 1;
+	}
+out:
+	return ret;
+}
+
+/* Verify if we need to do a flush for the new process, i.e. if there are any
+ * present desc's, only if they haven't been flushed.
+ */
+static inline int needs_TLS_update(struct task_struct *task)
+{
+	int i;
+	int ret = 0;
+
+	for (i = GDT_ENTRY_TLS_MIN; i < GDT_ENTRY_TLS_MAX; i++) {
+		struct uml_tls_struct* curr = &task->thread.arch.tls_array[i - GDT_ENTRY_TLS_MIN];
+
+		/* Can't test curr->present, we may need to clear a descriptor
+		 * which had a value. */
+		if (curr->flushed)
+			continue;
+		ret = 1;
+		break;
+	}
+	return ret;
+}
+
+/* On a newly forked process, the TLS descriptors haven't yet been flushed. So
+ * we mark them as such and the first switch_to will do the job.
+ */
+void clear_flushed_tls(struct task_struct *task)
+{
+	int i;
+
+	for (i = GDT_ENTRY_TLS_MIN; i < GDT_ENTRY_TLS_MAX; i++) {
+		struct uml_tls_struct* curr = &task->thread.arch.tls_array[i - GDT_ENTRY_TLS_MIN];
+
+		/* Still correct to do this, if it wasn't present on the host it
+		 * will remain as flushed as it was. */
+		if (!curr->present)
+			continue;
+
+		curr->flushed = 0;
+	}
+}
+
+/* In SKAS0 mode, currently, multiple guest threads sharing the same ->mm have a
+ * common host process. So this is needed in SKAS0 too.
+ *
+ * However, if each thread had a different host process (and this was discussed
+ * for SMP support) this won't be needed.
+ *
+ * And this will not need be used when (and if) we'll add support to the host
+ * SKAS patch. */
+
+int arch_switch_tls_skas(struct task_struct *from, struct task_struct *to)
+{
+	if (!host_supports_tls)
+		return 0;
+
+	/* We have no need whatsoever to switch TLS for kernel threads; beyond
+	 * that, that would also result in us calling os_set_thread_area with
+	 * userspace_pid[cpu] == 0, which gives an error. */
+	if (likely(to->mm))
+		return load_TLS(O_FORCE, to);
+
+	return 0;
+}
+
+int arch_switch_tls_tt(struct task_struct *from, struct task_struct *to)
+{
+	if (!host_supports_tls)
+		return 0;
+
+	if (needs_TLS_update(to))
+		return load_TLS(0, to);
+
+	return 0;
+}
+
+static int set_tls_entry(struct task_struct* task, struct user_desc *info,
+			 int idx, int flushed)
+{
+	struct thread_struct *t = &task->thread;
+
+	if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
+		return -EINVAL;
+
+	t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].tls = *info;
+	t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].present = 1;
+	t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].flushed = flushed;
+
+	return 0;
+}
+
+int arch_copy_tls(struct task_struct *new)
+{
+	struct user_desc info;
+	int idx, ret = -EFAULT;
+
+	if (copy_from_user(&info,
+			   (void __user *) UPT_ESI(&new->thread.regs.regs),
+			   sizeof(info)))
+		goto out;
+
+	ret = -EINVAL;
+	if (LDT_empty(&info))
+		goto out;
+
+	idx = info.entry_number;
+
+	ret = set_tls_entry(new, &info, idx, 0);
+out:
+	return ret;
+}
+
+/* XXX: use do_get_thread_area to read the host value? I'm not at all sure! */
+static int get_tls_entry(struct task_struct* task, struct user_desc *info, int idx)
+{
+	struct thread_struct *t = &task->thread;
+
+	if (!t->arch.tls_array)
+		goto clear;
+
+	if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
+		return -EINVAL;
+
+	if (!t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].present)
+		goto clear;
+
+	*info = t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].tls;
+
+out:
+	/* Temporary debugging check, to make sure that things have been
+	 * flushed. This could be triggered if load_TLS() failed.
+	 */
+	if (unlikely(task == current && !t->arch.tls_array[idx - GDT_ENTRY_TLS_MIN].flushed)) {
+		printk(KERN_ERR "get_tls_entry: task with pid %d got here "
+				"without flushed TLS.", current->pid);
+	}
+
+	return 0;
+clear:
+	/* When the TLS entry has not been set, the values read to user in the
+	 * tls_array are 0 (because it's cleared at boot, see
+	 * arch/i386/kernel/head.S:cpu_gdt_table). Emulate that.
+	 */
+	clear_user_desc(info);
+	info->entry_number = idx;
+	goto out;
+}
+
+asmlinkage int sys_set_thread_area(struct user_desc __user *user_desc)
+{
+	struct user_desc info;
+	int idx, ret;
+
+	if (!host_supports_tls)
+		return -ENOSYS;
+
+	if (copy_from_user(&info, user_desc, sizeof(info)))
+		return -EFAULT;
+
+	idx = info.entry_number;
+
+	if (idx == -1) {
+		idx = get_free_idx(current);
+		if (idx < 0)
+			return idx;
+		info.entry_number = idx;
+		/* Tell the user which slot we chose for him.*/
+		if (put_user(idx, &user_desc->entry_number))
+			return -EFAULT;
+	}
+
+	ret = CHOOSE_MODE_PROC(do_set_thread_area_tt, do_set_thread_area_skas, &info);
+	if (ret)
+		return ret;
+	return set_tls_entry(current, &info, idx, 1);
+}
+
+/*
+ * Perform set_thread_area on behalf of the traced child.
+ * Note: error handling is not done on the deferred load, and this differ from
+ * i386. However the only possible error are caused by bugs.
+ */
+int ptrace_set_thread_area(struct task_struct *child, int idx,
+		struct user_desc __user *user_desc)
+{
+	struct user_desc info;
+
+	if (!host_supports_tls)
+		return -EIO;
+
+	if (copy_from_user(&info, user_desc, sizeof(info)))
+		return -EFAULT;
+
+	return set_tls_entry(child, &info, idx, 0);
+}
+
+asmlinkage int sys_get_thread_area(struct user_desc __user *user_desc)
+{
+	struct user_desc info;
+	int idx, ret;
+
+	if (!host_supports_tls)
+		return -ENOSYS;
+
+	if (get_user(idx, &user_desc->entry_number))
+		return -EFAULT;
+
+	ret = get_tls_entry(current, &info, idx);
+	if (ret < 0)
+		goto out;
+
+	if (copy_to_user(user_desc, &info, sizeof(info)))
+		ret = -EFAULT;
+
+out:
+	return ret;
+}
+
+/*
+ * Perform get_thread_area on behalf of the traced child.
+ */
+int ptrace_get_thread_area(struct task_struct *child, int idx,
+		struct user_desc __user *user_desc)
+{
+	struct user_desc info;
+	int ret;
+
+	if (!host_supports_tls)
+		return -EIO;
+
+	ret = get_tls_entry(child, &info, idx);
+	if (ret < 0)
+		goto out;
+
+	if (copy_to_user(user_desc, &info, sizeof(info)))
+		ret = -EFAULT;
+out:
+	return ret;
+}
+
+
+/* XXX: This part is probably common to i386 and x86-64. Don't create a common
+ * file for now, do that when implementing x86-64 support.*/
+static int __init __setup_host_supports_tls(void) {
+	check_host_supports_tls(&host_supports_tls, &host_gdt_entry_tls_min);
+	if (host_supports_tls) {
+		printk(KERN_INFO "Host TLS support detected\n");
+		printk(KERN_INFO "Detected host type: ");
+		switch (host_gdt_entry_tls_min) {
+			case GDT_ENTRY_TLS_MIN_I386:
+				printk("i386\n");
+				break;
+			case GDT_ENTRY_TLS_MIN_X86_64:
+				printk("x86_64\n");
+				break;
+		}
+	} else
+		printk(KERN_ERR "  Host TLS support NOT detected! "
+				"TLS support inside UML will not work\n");
+	return 0;
+}
+
+__initcall(__setup_host_supports_tls);
diff --git a/arch/um/sys-x86_64/Makefile b/arch/um/sys-x86_64/Makefile
index a351091fbd9..b5fc22babdd 100644
--- a/arch/um/sys-x86_64/Makefile
+++ b/arch/um/sys-x86_64/Makefile
@@ -4,31 +4,23 @@
 # Licensed under the GPL
 #
 
-#XXX: why into lib-y?
-lib-y = bitops.o bugs.o csum-partial.o delay.o fault.o ldt.o mem.o memcpy.o \
-	ptrace.o ptrace_user.o sigcontext.o signal.o syscalls.o \
-	syscall_table.o sysrq.o thunk.o
-lib-$(CONFIG_MODE_SKAS) += stub.o stub_segv.o
+obj-y = bugs.o delay.o fault.o ldt.o mem.o ptrace.o ptrace_user.o \
+	sigcontext.o signal.o syscalls.o syscall_table.o sysrq.o ksyms.o \
+	tls.o
 
-obj-y := ksyms.o
-obj-$(CONFIG_MODULES) += module.o um_module.o
+obj-$(CONFIG_MODE_SKAS) += stub.o stub_segv.o
+obj-$(CONFIG_MODULES) += um_module.o
 
-USER_OBJS := ptrace_user.o sigcontext.o stub_segv.o
+subarch-obj-y = lib/bitops.o lib/csum-partial.o lib/memcpy.o lib/thunk.o
+subarch-obj-$(CONFIG_MODULES) += kernel/module.o
 
-SYMLINKS = bitops.c csum-copy.S csum-partial.c csum-wrappers.c ldt.c memcpy.S \
-	thunk.S module.c
+ldt-y = ../sys-i386/ldt.o
 
-include arch/um/scripts/Makefile.rules
+USER_OBJS := ptrace_user.o sigcontext.o stub_segv.o
 
-bitops.c-dir = lib
-csum-copy.S-dir = lib
-csum-partial.c-dir = lib
-csum-wrappers.c-dir = lib
-ldt.c-dir = /arch/um/sys-i386
-memcpy.S-dir = lib
-thunk.S-dir = lib
-module.c-dir = kernel
+include arch/um/scripts/Makefile.rules
 
-$(obj)/stub_segv.o: _c_flags = $(call unprofile,$(CFLAGS))
+extra-$(CONFIG_MODE_TT) += unmap.o
 
-include arch/um/scripts/Makefile.unmap
+$(obj)/stub_segv.o $(obj)/unmap.o: \
+	_c_flags = $(call unprofile,$(CFLAGS))
diff --git a/arch/um/sys-x86_64/signal.c b/arch/um/sys-x86_64/signal.c
index e75c4e1838b..a4c46a8af00 100644
--- a/arch/um/sys-x86_64/signal.c
+++ b/arch/um/sys-x86_64/signal.c
@@ -137,7 +137,7 @@ int copy_sc_to_user_tt(struct sigcontext *to, struct _fpstate *fp,
 	 * delivery.  The sp passed in is the original, and this needs
 	 * to be restored, so we stick it in separately.
 	 */
-	err |= copy_to_user(&SC_SP(to), sp, sizeof(sp));
+	err |= copy_to_user(&SC_SP(to), &sp, sizeof(sp));
 
 	if(from_fp != NULL){
 		err |= copy_to_user(&to->fpstate, &to_fp, sizeof(to->fpstate));
diff --git a/arch/um/sys-x86_64/tls.c b/arch/um/sys-x86_64/tls.c
new file mode 100644
index 00000000000..ce1bf1b81c4
--- /dev/null
+++ b/arch/um/sys-x86_64/tls.c
@@ -0,0 +1,14 @@
+#include "linux/sched.h"
+
+void debug_arch_force_load_TLS(void)
+{
+}
+
+void clear_flushed_tls(struct task_struct *task)
+{
+}
+
+int arch_copy_tls(struct task_struct *t)
+{
+        return 0;
+}