21 files changed, 536 insertions, 511 deletions

diff --git a/arch/um/os-Linux/aio.c b/arch/um/os-Linux/aio.c
index 6ff12743a0bd..9bf944f6a1db 100644
--- a/arch/um/os-Linux/aio.c
+++ b/arch/um/os-Linux/aio.c
@@ -132,10 +132,10 @@ static int aio_thread(void *arg)
                                 { .data = (void *) (long) event.data,
                                                 .err    = event.res });
                         reply_fd = ((struct aio_context *) reply.data)->reply_fd;
-                        err = os_write_file(reply_fd, &reply, sizeof(reply));
+                        err = write(reply_fd, &reply, sizeof(reply));
                         if(err != sizeof(reply))
                                 printk("aio_thread - write failed, fd = %d, "
-                                       "err = %d\n", reply_fd, -err);
+                                       "err = %d\n", reply_fd, errno);
                 }
         }
         return 0;
@@ -146,38 +146,31 @@ static int aio_thread(void *arg)
 static int do_not_aio(struct aio_thread_req *req)
 {
         char c;
-        int err;
+        unsigned long long actual;
+        int n;
+
+        actual = lseek64(req->io_fd, req->offset, SEEK_SET);
+        if(actual != req->offset)
+                return -errno;
 
         switch(req->type){
         case AIO_READ:
-                err = os_seek_file(req->io_fd, req->offset);
-                if(err)
-                        goto out;
-
-                err = os_read_file(req->io_fd, req->buf, req->len);
+                n = read(req->io_fd, req->buf, req->len);
                 break;
         case AIO_WRITE:
-                err = os_seek_file(req->io_fd, req->offset);
-                if(err)
-                        goto out;
-
-                err = os_write_file(req->io_fd, req->buf, req->len);
+                n = write(req->io_fd, req->buf, req->len);
                 break;
         case AIO_MMAP:
-                err = os_seek_file(req->io_fd, req->offset);
-                if(err)
-                        goto out;
-
-                err = os_read_file(req->io_fd, &c, sizeof(c));
+                n = read(req->io_fd, &c, sizeof(c));
                 break;
         default:
                 printk("do_not_aio - bad request type : %d\n", req->type);
-                err = -EINVAL;
-                break;
+                return -EINVAL;
         }
 
-out:
-        return err;
+        if(n < 0)
+                return -errno;
+        return 0;
 }
 
 /* These are initialized in initcalls and not changed */
@@ -193,12 +186,12 @@ static int not_aio_thread(void *arg)
 
         signal(SIGWINCH, SIG_IGN);
         while(1){
-                err = os_read_file(aio_req_fd_r, &req, sizeof(req));
+                err = read(aio_req_fd_r, &req, sizeof(req));
                 if(err != sizeof(req)){
                         if(err < 0)
                                 printk("not_aio_thread - read failed, "
                                        "fd = %d, err = %d\n", aio_req_fd_r,
-                                       -err);
+                                       errno);
                         else {
                                 printk("not_aio_thread - short read, fd = %d, "
                                        "length = %d\n", aio_req_fd_r, err);
@@ -207,11 +200,11 @@ static int not_aio_thread(void *arg)
                 }
                 err = do_not_aio(&req);
                 reply = ((struct aio_thread_reply) { .data      = req.aio,
-                                         .err   = err });
-                err = os_write_file(req.aio->reply_fd, &reply, sizeof(reply));
+                                                     .err       = err });
+                err = write(req.aio->reply_fd, &reply, sizeof(reply));
                 if(err != sizeof(reply))
                         printk("not_aio_thread - write failed, fd = %d, "
-                               "err = %d\n", req.aio->reply_fd, -err);
+                               "err = %d\n", req.aio->reply_fd, errno);
         }
 
         return 0;
@@ -228,6 +221,11 @@ static int init_aio_24(void)
 
         aio_req_fd_w = fds[0];
         aio_req_fd_r = fds[1];
+
+        err = os_set_fd_block(aio_req_fd_w, 0);
+        if(err)
+                goto out_close_pipe;
+
         err = run_helper_thread(not_aio_thread, NULL,
                                 CLONE_FILES | CLONE_VM | SIGCHLD, &stack, 0);
         if(err < 0)
@@ -285,10 +283,12 @@ static int submit_aio_26(enum aio_type type, int io_fd, char *buf, int len,
         if(err){
                 reply = ((struct aio_thread_reply) { .data = aio,
                                          .err  = err });
-                err = os_write_file(aio->reply_fd, &reply, sizeof(reply));
-                if(err != sizeof(reply))
+                err = write(aio->reply_fd, &reply, sizeof(reply));
+                if(err != sizeof(reply)){
+                        err = -errno;
                         printk("submit_aio_26 - write failed, "
                                "fd = %d, err = %d\n", aio->reply_fd, -err);
+                }
                 else err = 0;
         }
 
@@ -383,9 +383,10 @@ static int submit_aio_24(enum aio_type type, int io_fd, char *buf, int len,
         };
         int err;
 
-        err = os_write_file(aio_req_fd_w, &req, sizeof(req));
+        err = write(aio_req_fd_w, &req, sizeof(req));
         if(err == sizeof(req))
                 err = 0;
+        else err = -errno;
 
         return err;
 }
diff --git a/arch/um/os-Linux/drivers/ethertap_user.c b/arch/um/os-Linux/drivers/ethertap_user.c
index 863981ba1468..acba30161287 100644
--- a/arch/um/os-Linux/drivers/ethertap_user.c
+++ b/arch/um/os-Linux/drivers/ethertap_user.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and 
+ * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and
  * James Leu (jleu@mindspring.net).
  * Copyright (C) 2001 by various other people who didn't put their name here.
  * Licensed under the GPL.
@@ -16,19 +16,20 @@
 #include <net/if.h>
 #include "user.h"
 #include "kern_util.h"
-#include "user_util.h"
 #include "net_user.h"
 #include "etap.h"
 #include "os.h"
 #include "um_malloc.h"
+#include "kern_constants.h"
 
 #define MAX_PACKET ETH_MAX_PACKET
 
-void etap_user_init(void *data, void *dev)
+static int etap_user_init(void *data, void *dev)
 {
         struct ethertap_data *pri = data;
 
         pri->dev = dev;
+        return 0;
 }
 
 struct addr_change {
@@ -47,13 +48,16 @@ static void etap_change(int op, unsigned char *addr, unsigned char *netmask,
         change.what = op;
         memcpy(change.addr, addr, sizeof(change.addr));
         memcpy(change.netmask, netmask, sizeof(change.netmask));
-        n = os_write_file(fd, &change, sizeof(change));
-        if(n != sizeof(change))
-                printk("etap_change - request failed, err = %d\n", -n);
-        output = um_kmalloc(page_size());
+        CATCH_EINTR(n = write(fd, &change, sizeof(change)));
+        if(n != sizeof(change)){
+                printk("etap_change - request failed, err = %d\n", errno);
+                return;
+        }
+
+        output = um_kmalloc(UM_KERN_PAGE_SIZE);
         if(output == NULL)
                 printk("etap_change : Failed to allocate output buffer\n");
-        read_output(fd, output, page_size());
+        read_output(fd, output, UM_KERN_PAGE_SIZE);
         if(output != NULL){
                 printk("%s", output);
                 kfree(output);
@@ -115,13 +119,15 @@ static int etap_tramp(char *dev, char *gate, int control_me,
         pe_data.data_me = data_me;
         pid = run_helper(etap_pre_exec, &pe_data, args, NULL);
 
-        if(pid < 0) err = pid;
+        if(pid < 0)
+                err = pid;
         os_close_file(data_remote);
         os_close_file(control_remote);
-        n = os_read_file(control_me, &c, sizeof(c));
+        CATCH_EINTR(n = read(control_me, &c, sizeof(c)));
         if(n != sizeof(c)){
-                printk("etap_tramp : read of status failed, err = %d\n", -n);
-                return(-EINVAL);
+                err = -errno;
+                printk("etap_tramp : read of status failed, err = %d\n", -err);
+                return err;
         }
         if(c != 1){
                 printk("etap_tramp : uml_net failed\n");
@@ -132,7 +138,7 @@ static int etap_tramp(char *dev, char *gate, int control_me,
                 else if(!WIFEXITED(status) || (WEXITSTATUS(status) != 1))
                         printk("uml_net didn't exit with status 1\n");
         }
-        return(err);
+        return err;
 }
 
 static int etap_open(void *data)
@@ -142,23 +148,24 @@ static int etap_open(void *data)
         int data_fds[2], control_fds[2], err, output_len;
 
         err = tap_open_common(pri->dev, pri->gate_addr);
-        if(err) return(err);
+        if(err)
+                return err;
 
         err = os_pipe(data_fds, 0, 0);
         if(err < 0){
                 printk("data os_pipe failed - err = %d\n", -err);
-                return(err);
+                return err;
         }
 
         err = os_pipe(control_fds, 1, 0);
         if(err < 0){
                 printk("control os_pipe failed - err = %d\n", -err);
-                return(err);
+                return err;
         }
-        
+
         err = etap_tramp(pri->dev_name, pri->gate_addr, control_fds[0], 
                          control_fds[1], data_fds[0], data_fds[1]);
-        output_len = page_size();
+        output_len = UM_KERN_PAGE_SIZE;
         output = um_kmalloc(output_len);
         read_output(control_fds[0], output, output_len);
 
@@ -171,13 +178,13 @@ static int etap_open(void *data)
 
         if(err < 0){
                 printk("etap_tramp failed - err = %d\n", -err);
-                return(err);
+                return err;
         }
 
         pri->data_fd = data_fds[0];
         pri->control_fd = control_fds[0];
         iter_addresses(pri->dev, etap_open_addr, &pri->control_fd);
-        return(data_fds[0]);
+        return data_fds[0];
 }
 
 static void etap_close(int fd, void *data)
@@ -195,7 +202,7 @@ static void etap_close(int fd, void *data)
 
 static int etap_set_mtu(int mtu, void *data)
 {
-        return(mtu);
+        return mtu;
 }
 
 static void etap_add_addr(unsigned char *addr, unsigned char *netmask,
@@ -204,7 +211,8 @@ static void etap_add_addr(unsigned char *addr, unsigned char *netmask,
         struct ethertap_data *pri = data;
 
         tap_check_ips(pri->gate_addr, addr);
-        if(pri->control_fd == -1) return;
+        if(pri->control_fd == -1)
+                return;
         etap_open_addr(addr, netmask, &pri->control_fd);
 }
 
@@ -213,7 +221,8 @@ static void etap_del_addr(unsigned char *addr, unsigned char *netmask,
 {
         struct ethertap_data *pri = data;
 
-        if(pri->control_fd == -1) return;
+        if(pri->control_fd == -1)
+                return;
         etap_close_addr(addr, netmask, &pri->control_fd);
 }
 
@@ -227,14 +236,3 @@ const struct net_user_info ethertap_user_info = {
         .delete_address = etap_del_addr,
         .max_packet     = MAX_PACKET - ETH_HEADER_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/tuntap_user.c b/arch/um/os-Linux/drivers/tuntap_user.c
index e846b23f7558..11a9779dc9f1 100644
--- a/arch/um/os-Linux/drivers/tuntap_user.c
+++ b/arch/um/os-Linux/drivers/tuntap_user.c
@@ -18,17 +18,17 @@
 #include "net_user.h"
 #include "tuntap.h"
 #include "kern_util.h"
-#include "user_util.h"
 #include "user.h"
 #include "os.h"
 
 #define MAX_PACKET ETH_MAX_PACKET
 
-void tuntap_user_init(void *data, void *dev)
+static int tuntap_user_init(void *data, void *dev)
 {
         struct tuntap_data *pri = data;
 
         pri->dev = dev;
+        return 0;
 }
 
 static void tuntap_add_addr(unsigned char *addr, unsigned char *netmask,
@@ -37,7 +37,8 @@ static void tuntap_add_addr(unsigned char *addr, unsigned char *netmask,
         struct tuntap_data *pri = data;
 
         tap_check_ips(pri->gate_addr, addr);
-        if((pri->fd == -1) || pri->fixed_config) return;
+        if((pri->fd == -1) || pri->fixed_config)
+                return;
         open_addr(addr, netmask, pri->dev_name);
 }
 
@@ -46,7 +47,8 @@ static void tuntap_del_addr(unsigned char *addr, unsigned char *netmask,
 {
         struct tuntap_data *pri = data;
 
-        if((pri->fd == -1) || pri->fixed_config) return;
+        if((pri->fd == -1) || pri->fixed_config)
+                return;
         close_addr(addr, netmask, pri->dev_name);
 }
 
@@ -58,7 +60,7 @@ struct tuntap_pre_exec_data {
 static void tuntap_pre_exec(void *arg)
 {
         struct tuntap_pre_exec_data *data = arg;
-        
+
         dup2(data->stdout, 1);
         os_close_file(data->close_me);
 }
@@ -83,7 +85,8 @@ static int tuntap_open_tramp(char *gate, int *fd_out, int me, int remote,
 
         pid = run_helper(tuntap_pre_exec, &data, argv, NULL);
 
-        if(pid < 0) return(-pid);
+        if(pid < 0)
+                return -pid;
 
         os_close_file(remote);
 
@@ -114,16 +117,16 @@ static int tuntap_open_tramp(char *gate, int *fd_out, int me, int remote,
         cmsg = CMSG_FIRSTHDR(&msg);
         if(cmsg == NULL){
                 printk("tuntap_open_tramp : didn't receive a message\n");
-                return(-EINVAL);
+                return -EINVAL;
         }
         if((cmsg->cmsg_level != SOL_SOCKET) || 
            (cmsg->cmsg_type != SCM_RIGHTS)){
                 printk("tuntap_open_tramp : didn't receive a descriptor\n");
-                return(-EINVAL);
+                return -EINVAL;
         }
         *fd_out = ((int *) CMSG_DATA(cmsg))[0];
         os_set_exec_close(*fd_out, 1);
-        return(0);
+        return 0;
 }
 
 static int tuntap_open(void *data)
@@ -135,7 +138,7 @@ static int tuntap_open(void *data)
 
         err = tap_open_common(pri->dev, pri->gate_addr);
         if(err < 0)
-                return(err);
+                return err;
 
         if(pri->fixed_config){
                 pri->fd = os_open_file("/dev/net/tun",
@@ -143,7 +146,7 @@ static int tuntap_open(void *data)
                 if(pri->fd < 0){
                         printk("Failed to open /dev/net/tun, err = %d\n",
                                -pri->fd);
-                        return(pri->fd);
+                        return pri->fd;
                 }
                 memset(&ifr, 0, sizeof(ifr));
                 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
@@ -160,7 +163,7 @@ static int tuntap_open(void *data)
                 if(err < 0){
                         printk("tuntap_open : os_pipe failed - err = %d\n",
                                -err);
-                        return(err);
+                        return err;
                 }
 
                 buffer = get_output_buffer(&len);
@@ -175,7 +178,7 @@ static int tuntap_open(void *data)
                         printk("%s", output);
                         free_output_buffer(buffer);
                         printk("tuntap_open_tramp failed - err = %d\n", -err);
-                        return(err);
+                        return err;
                 }
 
                 pri->dev_name = uml_strdup(buffer);
@@ -187,7 +190,7 @@ static int tuntap_open(void *data)
                 iter_addresses(pri->dev, open_addr, pri->dev_name);
         }
 
-        return(pri->fd);
+        return pri->fd;
 }
 
 static void tuntap_close(int fd, void *data)
@@ -202,7 +205,7 @@ static void tuntap_close(int fd, void *data)
 
 static int tuntap_set_mtu(int mtu, void *data)
 {
-        return(mtu);
+        return mtu;
 }
 
 const struct net_user_info tuntap_user_info = {
@@ -215,14 +218,3 @@ const struct net_user_info tuntap_user_info = {
         .delete_address = tuntap_del_addr,
         .max_packet     = MAX_PACKET
 };
-
-/*
- * 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/file.c b/arch/um/os-Linux/file.c
index 371b4335f46d..6f92f732d253 100644
--- a/arch/um/os-Linux/file.c
+++ b/arch/um/os-Linux/file.c
@@ -18,7 +18,6 @@
 #include "os.h"
 #include "user.h"
 #include "kern_util.h"
-#include "user_util.h"
 
 static void copy_stat(struct uml_stat *dst, struct stat64 *src)
 {
@@ -291,54 +290,22 @@ int os_seek_file(int fd, __u64 offset)
         return 0;
 }
 
-static int fault_buffer(void *start, int len,
-                        int (*copy_proc)(void *addr, void *buf, int len))
-{
-        int page = getpagesize(), i;
-        char c;
-
-        for(i = 0; i < len; i += page){
-                if((*copy_proc)(start + i, &c, sizeof(c)))
-                        return -EFAULT;
-        }
-        if((len % page) != 0){
-                if((*copy_proc)(start + len - 1, &c, sizeof(c)))
-                        return -EFAULT;
-        }
-        return 0;
-}
-
-static int file_io(int fd, void *buf, int len,
-                   int (*io_proc)(int fd, void *buf, int len),
-                   int (*copy_user_proc)(void *addr, void *buf, int len))
+int os_read_file(int fd, void *buf, int len)
 {
-        int n, err;
-
-        do {
-                n = (*io_proc)(fd, buf, len);
-                if((n < 0) && (errno == EFAULT)){
-                        err = fault_buffer(buf, len, copy_user_proc);
-                        if(err)
-                                return err;
-                        n = (*io_proc)(fd, buf, len);
-                }
-        } while((n < 0) && (errno == EINTR));
+        int n = read(fd, buf, len);
 
         if(n < 0)
                 return -errno;
         return n;
 }
 
-int os_read_file(int fd, void *buf, int len)
-{
-        return file_io(fd, buf, len, (int (*)(int, void *, int)) read,
-                       copy_from_user_proc);
-}
-
 int os_write_file(int fd, const void *buf, int len)
 {
-        return file_io(fd, (void *) buf, len,
-                       (int (*)(int, void *, int)) write, copy_to_user_proc);
+        int n = write(fd, (void *) buf, len);
+
+        if(n < 0)
+                return -errno;
+        return n;
 }
 
 int os_file_size(char *file, unsigned long long *size_out)
diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
index c7ad6306e22f..97bed16bf4c7 100644
--- a/arch/um/os-Linux/helper.c
+++ b/arch/um/os-Linux/helper.c
@@ -13,9 +13,9 @@
 #include <sys/wait.h>
 #include "user.h"
 #include "kern_util.h"
-#include "user_util.h"
 #include "os.h"
 #include "um_malloc.h"
+#include "kern_constants.h"
 
 struct helper_data {
         void (*pre_exec)(void*);
@@ -25,28 +25,18 @@ struct helper_data {
         char *buf;
 };
 
-/* Debugging aid, changed only from gdb */
-int helper_pause = 0;
-
-static void helper_hup(int sig)
-{
-}
-
 static int helper_child(void *arg)
 {
         struct helper_data *data = arg;
         char **argv = data->argv;
         int errval;
 
-        if (helper_pause){
-                signal(SIGHUP, helper_hup);
-                pause();
-        }
         if (data->pre_exec != NULL)
                 (*data->pre_exec)(data->pre_data);
         errval = execvp_noalloc(data->buf, argv[0], argv);
-        printk("helper_child - execvp of '%s' failed - errno = %d\n", argv[0], -errval);
-        os_write_file(data->fd, &errval, sizeof(errval));
+        printk("helper_child - execvp of '%s' failed - errno = %d\n", argv[0],
+               -errval);
+        write(data->fd, &errval, sizeof(errval));
         kill(os_getpid(), SIGKILL);
         return 0;
 }
@@ -81,7 +71,7 @@ int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv,
                 goto out_close;
         }
 
-        sp = stack + page_size() - sizeof(void *);
+        sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *);
         data.pre_exec = pre_exec;
         data.pre_data = pre_data;
         data.argv = argv;
@@ -98,13 +88,16 @@ 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, 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));
+        /*
+         * 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 = read(fds[0], &ret, sizeof(ret));
         if (n == 0) {
                 ret = pid;
         } else {
                 if (n < 0) {
+                        n = -errno;
                         printk("run_helper : read on pipe failed, ret = %d\n",
                                -n);
                         ret = n;
@@ -135,7 +128,7 @@ int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
         if (stack == 0)
                 return -ENOMEM;
 
-        sp = stack + (page_size() << stack_order) - sizeof(void *);
+        sp = stack + (UM_KERN_PAGE_SIZE << stack_order) - sizeof(void *);
         pid = clone(proc, (void *) sp, flags | SIGCHLD, arg);
         if (pid < 0) {
                 err = -errno;
diff --git a/arch/um/os-Linux/irq.c b/arch/um/os-Linux/irq.c
index d1b61d474e0a..a633fa8e0a94 100644
--- a/arch/um/os-Linux/irq.c
+++ b/arch/um/os-Linux/irq.c
@@ -11,7 +11,6 @@
 #include <sys/poll.h>
 #include <sys/types.h>
 #include <sys/time.h>
-#include "user_util.h"
 #include "kern_util.h"
 #include "user.h"
 #include "process.h"
diff --git a/arch/um/os-Linux/main.c b/arch/um/os-Linux/main.c
index 685feaab65d2..ea9a23696f36 100644
--- a/arch/um/os-Linux/main.c
+++ b/arch/um/os-Linux/main.c
@@ -13,8 +13,8 @@
 #include <sys/mman.h>
 #include <sys/user.h>
 #include <asm/page.h>
-#include "user_util.h"
 #include "kern_util.h"
+#include "as-layout.h"
 #include "mem_user.h"
 #include "irq_user.h"
 #include "user.h"
@@ -25,12 +25,7 @@
 #include "os.h"
 #include "um_malloc.h"
 
-/* Set in set_stklim, which is called from main and __wrap_malloc.
- * __wrap_malloc only calls it if main hasn't started.
- */
-unsigned long stacksizelim;
-
-/* Set in main */
+/* Set in main, unchanged thereafter */
 char *linux_prog;
 
 #define PGD_BOUND (4 * 1024 * 1024)
@@ -52,7 +47,6 @@ static void set_stklim(void)
                         exit(1);
                 }
         }
-        stacksizelim = (lim.rlim_cur + PGD_BOUND - 1) & ~(PGD_BOUND - 1);
 }
 
 static __init void do_uml_initcalls(void)
@@ -126,7 +120,7 @@ extern int uml_exitcode;
 
 extern void scan_elf_aux( char **envp);
 
-int main(int argc, char **argv, char **envp)
+int __init main(int argc, char **argv, char **envp)
 {
         char **new_argv;
         int ret, i, err;
@@ -224,7 +218,7 @@ int main(int argc, char **argv, char **envp)
                 ret = 1;
         }
         printf("\n");
-        return(uml_exitcode);
+        return uml_exitcode;
 }
 
 #define CAN_KMALLOC() \
@@ -237,7 +231,7 @@ void *__wrap_malloc(int size)
         void *ret;
 
         if(!CAN_KMALLOC())
-                return(__real_malloc(size));
+                return __real_malloc(size);
         else if(size <= PAGE_SIZE) /* finding contiguos pages can be hard*/
                 ret = um_kmalloc(size);
         else ret = um_vmalloc(size);
@@ -248,16 +242,17 @@ void *__wrap_malloc(int size)
         if(ret == NULL)
                 errno = ENOMEM;
 
-        return(ret);
+        return ret;
 }
 
 void *__wrap_calloc(int n, int size)
 {
         void *ptr = __wrap_malloc(n * size);
 
-        if(ptr == NULL) return(NULL);
+        if(ptr == NULL)
+                return NULL;
         memset(ptr, 0, n * size);
-        return(ptr);
+        return ptr;
 }
 
 extern void __real_free(void *);
diff --git a/arch/um/os-Linux/mem.c b/arch/um/os-Linux/mem.c
index f1ea169db85e..c6378c6d10d2 100644
--- a/arch/um/os-Linux/mem.c
+++ b/arch/um/os-Linux/mem.c
@@ -11,7 +11,6 @@
 #include <sys/statfs.h>
 #include "kern_util.h"
 #include "user.h"
-#include "user_util.h"
 #include "mem_user.h"
 #include "init.h"
 #include "os.h"
@@ -165,7 +164,8 @@ found:
  * (file: kernel/tt/ptproxy/proxy.c, proc: start_debugger).
  * So it isn't 'static' yet.
  */
-int make_tempfile(const char *template, char **out_tempname, int do_unlink)
+int __init make_tempfile(const char *template, char **out_tempname,
+                         int do_unlink)
 {
         char *tempname;
         int fd;
@@ -206,7 +206,7 @@ out:
  * This proc is used in start_up.c
  * So it isn't 'static'.
  */
-int create_tmp_file(unsigned long long len)
+int __init create_tmp_file(unsigned long long len)
 {
         int fd, err;
         char zero;
@@ -232,17 +232,16 @@ int create_tmp_file(unsigned long long len)
 
         zero = 0;
 
-        err = os_write_file(fd, &zero, 1);
+        err = write(fd, &zero, 1);
         if(err != 1){
-                errno = -err;
-                perror("os_write_file");
+                perror("write");
                 exit(1);
         }
 
         return fd;
 }
 
-int create_mem_file(unsigned long long len)
+int __init create_mem_file(unsigned long long len)
 {
         int err, fd;
 
@@ -257,7 +256,7 @@ int create_mem_file(unsigned long long len)
 }
 
 
-void check_tmpexec(void)
+void __init check_tmpexec(void)
 {
         void *addr;
         int err, fd = create_tmp_file(UM_KERN_PAGE_SIZE);
diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c
index 76bdd6712417..92a7b59120d6 100644
--- a/arch/um/os-Linux/process.c
+++ b/arch/um/os-Linux/process.c
@@ -14,7 +14,6 @@
 #include "ptrace_user.h"
 #include "os.h"
 #include "user.h"
-#include "user_util.h"
 #include "process.h"
 #include "irq_user.h"
 #include "kern_util.h"
@@ -22,6 +21,7 @@
 #include "skas_ptrace.h"
 #include "kern_constants.h"
 #include "uml-config.h"
+#include "init.h"
 
 #define ARBITRARY_ADDR -1
 #define FAILURE_PID    -1
@@ -40,14 +40,14 @@ unsigned long os_process_pc(int pid)
         if(fd < 0){
                 printk("os_process_pc - couldn't open '%s', err = %d\n",
                        proc_stat, -fd);
-                return(ARBITRARY_ADDR);
+                return ARBITRARY_ADDR;
         }
-        err = os_read_file(fd, buf, sizeof(buf));
+        CATCH_EINTR(err = read(fd, buf, sizeof(buf)));
         if(err < 0){
                 printk("os_process_pc - couldn't read '%s', err = %d\n",
-                       proc_stat, -err);
+                       proc_stat, errno);
                 os_close_file(fd);
-                return(ARBITRARY_ADDR);
+                return ARBITRARY_ADDR;
         }
         os_close_file(fd);
         pc = ARBITRARY_ADDR;
@@ -56,7 +56,7 @@ unsigned long os_process_pc(int pid)
                   "%*d %*d %*d %*d %*d %lu", &pc) != 1){
                 printk("os_process_pc - couldn't find pc in '%s'\n", buf);
         }
-        return(pc);
+        return pc;
 }
 
 int os_process_parent(int pid)
@@ -65,21 +65,22 @@ int os_process_parent(int pid)
         char data[256];
         int parent, n, fd;
 
-        if(pid == -1) return(-1);
+        if(pid == -1)
+                return -1;
 
         snprintf(stat, sizeof(stat), "/proc/%d/stat", pid);
         fd = os_open_file(stat, of_read(OPENFLAGS()), 0);
         if(fd < 0){
                 printk("Couldn't open '%s', err = %d\n", stat, -fd);
-                return(FAILURE_PID);
+                return FAILURE_PID;
         }
 
-        n = os_read_file(fd, data, sizeof(data));
+        CATCH_EINTR(n = read(fd, data, sizeof(data)));
         os_close_file(fd);
 
         if(n < 0){
-                printk("Couldn't read '%s', err = %d\n", stat, -n);
-                return(FAILURE_PID);
+                printk("Couldn't read '%s', err = %d\n", stat, errno);
+                return FAILURE_PID;
         }
 
         parent = FAILURE_PID;
@@ -87,7 +88,7 @@ int os_process_parent(int pid)
         if(n != 1)
                 printk("Failed to scan '%s'\n", data);
 
-        return(parent);
+        return parent;
 }
 
 void os_stop_process(int pid)
@@ -145,7 +146,7 @@ void os_usr1_process(int pid)
 
 int os_getpid(void)
 {
-        return(syscall(__NR_getpid));
+        return syscall(__NR_getpid);
 }
 
 int os_getpgrp(void)
@@ -165,8 +166,8 @@ int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len,
         loc = mmap64((void *) virt, len, prot, MAP_SHARED | MAP_FIXED,
                      fd, off);
         if(loc == MAP_FAILED)
-                return(-errno);
-        return(0);
+                return -errno;
+        return 0;
 }
 
 int os_protect_memory(void *addr, unsigned long len, int r, int w, int x)
@@ -175,8 +176,8 @@ int os_protect_memory(void *addr, unsigned long len, int r, int w, int x)
                     (x ? PROT_EXEC : 0));
 
         if(mprotect(addr, len, prot) < 0)
-                return(-errno);
-        return(0);
+                return -errno;
+        return 0;
 }
 
 int os_unmap_memory(void *addr, int len)
@@ -185,15 +186,15 @@ int os_unmap_memory(void *addr, int len)
 
         err = munmap(addr, len);
         if(err < 0)
-                return(-errno);
-        return(0);
+                return -errno;
+        return 0;
 }
 
 #ifndef MADV_REMOVE
 #define MADV_REMOVE KERNEL_MADV_REMOVE
 #endif
 
-int os_drop_memory(void *addr, int length)
+int __init os_drop_memory(void *addr, int length)
 {
         int err;
 
@@ -203,7 +204,7 @@ int os_drop_memory(void *addr, int length)
         return err;
 }
 
-int can_drop_memory(void)
+int __init can_drop_memory(void)
 {
         void *addr;
         int fd, ok = 0;
@@ -244,7 +245,7 @@ void init_new_thread_stack(void *sig_stack, void (*usr1_handler)(int))
 
         if(sig_stack != NULL){
                 pages = (1 << UML_CONFIG_KERNEL_STACK_ORDER);
-                set_sigstack(sig_stack, pages * page_size());
+                set_sigstack(sig_stack, pages * UM_KERN_PAGE_SIZE);
                 flags = SA_ONSTACK;
         }
         if(usr1_handler){
diff --git a/arch/um/os-Linux/sigio.c b/arch/um/os-Linux/sigio.c
index 3fc43b33db66..8d4e0c6b8c92 100644
--- a/arch/um/os-Linux/sigio.c
+++ b/arch/um/os-Linux/sigio.c
@@ -8,6 +8,7 @@
 #include <termios.h>
 #include <pty.h>
 #include <signal.h>
+#include <fcntl.h>
 #include <errno.h>
 #include <string.h>
 #include <sched.h>
@@ -16,10 +17,10 @@
 #include "init.h"
 #include "user.h"
 #include "kern_util.h"
-#include "user_util.h"
 #include "sigio.h"
 #include "os.h"
 #include "um_malloc.h"
+#include "init.h"
 
 /* Protected by sigio_lock(), also used by sigio_cleanup, which is an
  * exitcall.
@@ -68,11 +69,12 @@ static int write_sigio_thread(void *unused)
                         p = &fds->poll[i];
                         if(p->revents == 0) continue;
                         if(p->fd == sigio_private[1]){
-                                n = os_read_file(sigio_private[1], &c, sizeof(c));
+                                CATCH_EINTR(n = read(sigio_private[1], &c,
+                                                     sizeof(c)));
                                 if(n != sizeof(c))
                                         printk("write_sigio_thread : "
                                                "read on socket failed, "
-                                               "err = %d\n", -n);
+                                               "err = %d\n", errno);
                                 tmp = current_poll;
                                 current_poll = next_poll;
                                 next_poll = tmp;
@@ -85,10 +87,10 @@ static int write_sigio_thread(void *unused)
                                         (fds->used - i) * sizeof(*fds->poll));
                         }
 
-                        n = os_write_file(respond_fd, &c, sizeof(c));
+                        CATCH_EINTR(n = write(respond_fd, &c, sizeof(c)));
                         if(n != sizeof(c))
                                 printk("write_sigio_thread : write on socket "
-                                       "failed, err = %d\n", -n);
+                                       "failed, err = %d\n", errno);
                 }
         }
 
@@ -126,15 +128,15 @@ static void update_thread(void)
         char c;
 
         flags = set_signals(0);
-        n = os_write_file(sigio_private[0], &c, sizeof(c));
+        n = write(sigio_private[0], &c, sizeof(c));
         if(n != sizeof(c)){
-                printk("update_thread : write failed, err = %d\n", -n);
+                printk("update_thread : write failed, err = %d\n", errno);
                 goto fail;
         }
 
-        n = os_read_file(sigio_private[0], &c, sizeof(c));
+        CATCH_EINTR(n = read(sigio_private[0], &c, sizeof(c)));
         if(n != sizeof(c)){
-                printk("update_thread : read failed, err = %d\n", -n);
+                printk("update_thread : read failed, err = %d\n", errno);
                 goto fail;
         }
 
@@ -320,6 +322,10 @@ out_close1:
         close(l_write_sigio_fds[1]);
 }
 
+/* Changed during early boot */
+static int pty_output_sigio = 0;
+static int pty_close_sigio = 0;
+
 void maybe_sigio_broken(int fd, int read)
 {
         int err;
@@ -357,3 +363,143 @@ static void sigio_cleanup(void)
 }
 
 __uml_exitcall(sigio_cleanup);
+
+/* Used as a flag during SIGIO testing early in boot */
+static volatile int got_sigio = 0;
+
+static void __init handler(int sig)
+{
+        got_sigio = 1;
+}
+
+struct openpty_arg {
+        int master;
+        int slave;
+        int err;
+};
+
+static void openpty_cb(void *arg)
+{
+        struct openpty_arg *info = arg;
+
+        info->err = 0;
+        if(openpty(&info->master, &info->slave, NULL, NULL, NULL))
+                info->err = -errno;
+}
+
+static int async_pty(int master, int slave)
+{
+        int flags;
+
+        flags = fcntl(master, F_GETFL);
+        if(flags < 0)
+                return -errno;
+
+        if((fcntl(master, F_SETFL, flags | O_NONBLOCK | O_ASYNC) < 0) ||
+           (fcntl(master, F_SETOWN, os_getpid()) < 0))
+                return -errno;
+
+        if((fcntl(slave, F_SETFL, flags | O_NONBLOCK) < 0))
+                return -errno;
+
+        return(0);
+}
+
+static void __init check_one_sigio(void (*proc)(int, int))
+{
+        struct sigaction old, new;
+        struct openpty_arg pty = { .master = -1, .slave = -1 };
+        int master, slave, err;
+
+        initial_thread_cb(openpty_cb, &pty);
+        if(pty.err){
+                printk("openpty failed, errno = %d\n", -pty.err);
+                return;
+        }
+
+        master = pty.master;
+        slave = pty.slave;
+
+        if((master == -1) || (slave == -1)){
+                printk("openpty failed to allocate a pty\n");
+                return;
+        }
+
+        /* Not now, but complain so we now where we failed. */
+        err = raw(master);
+        if (err < 0)
+                panic("check_sigio : __raw failed, errno = %d\n", -err);
+
+        err = async_pty(master, slave);
+        if(err < 0)
+                panic("tty_fds : sigio_async failed, err = %d\n", -err);
+
+        if(sigaction(SIGIO, NULL, &old) < 0)
+                panic("check_sigio : sigaction 1 failed, errno = %d\n", errno);
+        new = old;
+        new.sa_handler = handler;
+        if(sigaction(SIGIO, &new, NULL) < 0)
+                panic("check_sigio : sigaction 2 failed, errno = %d\n", errno);
+
+        got_sigio = 0;
+        (*proc)(master, slave);
+
+        close(master);
+        close(slave);
+
+        if(sigaction(SIGIO, &old, NULL) < 0)
+                panic("check_sigio : sigaction 3 failed, errno = %d\n", errno);
+}
+
+static void tty_output(int master, int slave)
+{
+        int n;
+        char buf[512];
+
+        printk("Checking that host ptys support output SIGIO...");
+
+        memset(buf, 0, sizeof(buf));
+
+        while(write(master, buf, sizeof(buf)) > 0) ;
+        if(errno != EAGAIN)
+                panic("tty_output : write failed, errno = %d\n", errno);
+        while(((n = read(slave, buf, sizeof(buf))) > 0) && !got_sigio) ;
+
+        if(got_sigio){
+                printk("Yes\n");
+                pty_output_sigio = 1;
+        }
+        else if(n == -EAGAIN)
+                printk("No, enabling workaround\n");
+        else panic("tty_output : read failed, err = %d\n", n);
+}
+
+static void tty_close(int master, int slave)
+{
+        printk("Checking that host ptys support SIGIO on close...");
+
+        close(slave);
+        if(got_sigio){
+                printk("Yes\n");
+                pty_close_sigio = 1;
+        }
+        else printk("No, enabling workaround\n");
+}
+
+void __init check_sigio(void)
+{
+        if((os_access("/dev/ptmx", OS_ACC_R_OK) < 0) &&
+           (os_access("/dev/ptyp0", OS_ACC_R_OK) < 0)){
+                printk("No pseudo-terminals available - skipping pty SIGIO "
+                       "check\n");
+                return;
+        }
+        check_one_sigio(tty_output);
+        check_one_sigio(tty_close);
+}
+
+/* Here because it only does the SIGIO testing for now */
+void __init os_check_bugs(void)
+{
+        check_sigio();
+}
diff --git a/arch/um/os-Linux/signal.c b/arch/um/os-Linux/signal.c
index 266768629fee..48d493415301 100644
--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -11,7 +11,6 @@
 #include <stdarg.h>
 #include <string.h>
 #include <sys/mman.h>
-#include "user_util.h"
 #include "user.h"
 #include "signal_kern.h"
 #include "sysdep/sigcontext.h"
diff --git a/arch/um/os-Linux/skas/mem.c b/arch/um/os-Linux/skas/mem.c
index 9383e8751ae7..8e490fff3d47 100644
--- a/arch/um/os-Linux/skas/mem.c
+++ b/arch/um/os-Linux/skas/mem.c
@@ -6,6 +6,7 @@
 #include <signal.h>
 #include <errno.h>
 #include <string.h>
+#include <unistd.h>
 #include <sys/mman.h>
 #include <sys/wait.h>
 #include <asm/page.h>
@@ -17,17 +18,17 @@
 #include "os.h"
 #include "proc_mm.h"
 #include "ptrace_user.h"
-#include "user_util.h"
 #include "kern_util.h"
 #include "task.h"
 #include "registers.h"
 #include "uml-config.h"
 #include "sysdep/ptrace.h"
 #include "sysdep/stub.h"
+#include "init.h"
 
 extern unsigned long batch_syscall_stub, __syscall_stub_start;
 
-extern void wait_stub_done(int pid, int sig, char * fname);
+extern void wait_stub_done(int pid);
 
 static inline unsigned long *check_init_stack(struct mm_id * mm_idp,
                                               unsigned long *stack)
@@ -39,6 +40,19 @@ static inline unsigned long *check_init_stack(struct mm_id * mm_idp,
         return stack;
 }
 
+static unsigned long syscall_regs[MAX_REG_NR];
+
+static int __init init_syscall_regs(void)
+{
+        get_safe_registers(syscall_regs, NULL);
+        syscall_regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
+                ((unsigned long) &batch_syscall_stub -
+                 (unsigned long) &__syscall_stub_start);
+        return 0;
+}
+
+__initcall(init_syscall_regs);
+
 extern int proc_mm;
 
 int single_count = 0;
@@ -47,12 +61,11 @@ int multi_op_count = 0;
 
 static inline long do_syscall_stub(struct mm_id * mm_idp, void **addr)
 {
-        unsigned long regs[MAX_REG_NR];
         int n, i;
         long ret, offset;
         unsigned long * data;
         unsigned long * syscall;
-        int pid = mm_idp->u.pid;
+        int err, pid = mm_idp->u.pid;
 
         if(proc_mm)
 #warning Need to look up userspace_pid by cpu
@@ -60,21 +73,21 @@ static inline long do_syscall_stub(struct mm_id * mm_idp, void **addr)
 
         multi_count++;
 
-        get_safe_registers(regs, NULL);
-        regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
-                ((unsigned long) &batch_syscall_stub -
-                 (unsigned long) &__syscall_stub_start);
-
-        n = ptrace_setregs(pid, regs);
+        n = ptrace_setregs(pid, syscall_regs);
         if(n < 0){
                 printk("Registers - \n");
                 for(i = 0; i < MAX_REG_NR; i++)
-                        printk("\t%d\t0x%lx\n", i, regs[i]);
+                        printk("\t%d\t0x%lx\n", i, syscall_regs[i]);
                 panic("do_syscall_stub : PTRACE_SETREGS failed, errno = %d\n",
                       -n);
         }
 
-        wait_stub_done(pid, 0, "do_syscall_stub");
+        err = ptrace(PTRACE_CONT, pid, 0, 0);
+        if(err)
+                panic("Failed to continue stub, pid = %d, errno = %d\n", pid,
+                      errno);
+
+        wait_stub_done(pid);
 
         /* When the stub stops, we find the following values on the
          * beginning of the stack:
@@ -176,14 +189,10 @@ long syscall_stub_data(struct mm_id * mm_idp,
         return 0;
 }
 
-int map(struct mm_id * mm_idp, unsigned long virt, unsigned long len,
-        int r, int w, int x, int phys_fd, unsigned long long offset,
-        int done, void **data)
+int map(struct mm_id * mm_idp, unsigned long virt, unsigned long len, int prot,
+        int phys_fd, unsigned long long offset, int done, void **data)
 {
-        int prot, ret;
-
-        prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
-                (x ? PROT_EXEC : 0);
+        int ret;
 
         if(proc_mm){
                 struct proc_mm_op map;
@@ -200,9 +209,11 @@ int map(struct mm_id * mm_idp, unsigned long virt, unsigned long len,
                                            .fd  = phys_fd,
                                            .offset= offset
                                          } } } );
-                ret = os_write_file(fd, &map, sizeof(map));
-                if(ret != sizeof(map))
+                CATCH_EINTR(ret = write(fd, &map, sizeof(map)));
+                if(ret != sizeof(map)){
+                        ret = -errno;
                         printk("map : /proc/mm map failed, err = %d\n", -ret);
+                }
                 else ret = 0;
         }
         else {
@@ -217,8 +228,8 @@ int map(struct mm_id * mm_idp, unsigned long virt, unsigned long len,
         return ret;
 }
 
-int unmap(struct mm_id * mm_idp, void *addr, unsigned long len, int done,
-          void **data)
+int unmap(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
+          int done, void **data)
 {
         int ret;
 
@@ -232,9 +243,11 @@ int unmap(struct mm_id * mm_idp, void *addr, unsigned long len, int done,
                                            { .addr      =
                                              (unsigned long) addr,
                                              .len               = len } } } );
-                ret = os_write_file(fd, &unmap, sizeof(unmap));
-                if(ret != sizeof(unmap))
+                CATCH_EINTR(ret = write(fd, &unmap, sizeof(unmap)));
+                if(ret != sizeof(unmap)){
+                        ret = -errno;
                         printk("unmap - proc_mm write returned %d\n", ret);
+                }
                 else ret = 0;
         }
         else {
@@ -249,13 +262,11 @@ int unmap(struct mm_id * mm_idp, void *addr, unsigned long len, int done,
 }
 
 int protect(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
-            int r, int w, int x, int done, void **data)
+            unsigned int prot, int done, void **data)
 {
         struct proc_mm_op protect;
-        int prot, ret;
+        int ret;
 
-        prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
-                (x ? PROT_EXEC : 0);
         if(proc_mm){
                 int fd = mm_idp->u.mm_fd;
 
@@ -267,9 +278,11 @@ int protect(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
                                                .len     = len,
                                                .prot    = prot } } } );
 
-                ret = os_write_file(fd, &protect, sizeof(protect));
-                if(ret != sizeof(protect))
+                CATCH_EINTR(ret = write(fd, &protect, sizeof(protect)));
+                if(ret != sizeof(protect)){
+                        ret = -errno;
                         printk("protect failed, err = %d", -ret);
+                }
                 else ret = 0;
         }
         else {
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 0564422c155f..5c088a55396c 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -18,7 +18,6 @@
 #include <asm/types.h>
 #include "user.h"
 #include "sysdep/ptrace.h"
-#include "user_util.h"
 #include "kern_util.h"
 #include "skas.h"
 #include "stub-data.h"
@@ -34,6 +33,8 @@
 #include "uml-config.h"
 #include "process.h"
 #include "longjmp.h"
+#include "kern_constants.h"
+#include "as-layout.h"
 
 int is_skas_winch(int pid, int fd, void *data)
 {
@@ -44,45 +45,58 @@ int is_skas_winch(int pid, int fd, void *data)
         return(1);
 }
 
-void wait_stub_done(int pid, int sig, char * fname)
+static int ptrace_dump_regs(int pid)
 {
-        int n, status, err;
+        unsigned long regs[MAX_REG_NR];
+        int i;
+
+        if(ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
+                return -errno;
+        else {
+                printk("Stub registers -\n");
+                for(i = 0; i < ARRAY_SIZE(regs); i++)
+                        printk("\t%d - %lx\n", i, regs[i]);
+        }
+
+        return 0;
+}
 
-        do {
-                if ( sig != -1 ) {
-                        err = ptrace(PTRACE_CONT, pid, 0, sig);
-                        if(err)
-                                panic("%s : continue failed, errno = %d\n",
-                                      fname, errno);
-                }
-                sig = 0;
+/*
+ * Signals that are OK to receive in the stub - we'll just continue it.
+ * SIGWINCH will happen when UML is inside a detached screen.
+ */
+#define STUB_SIG_MASK ((1 << SIGVTALRM) | (1 << SIGWINCH))
+
+/* Signals that the stub will finish with - anything else is an error */
+#define STUB_DONE_MASK ((1 << SIGUSR1) | (1 << SIGTRAP))
+
+void wait_stub_done(int pid)
+{
+        int n, status, err;
 
+        while(1){
                 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
-        } while((n >= 0) && WIFSTOPPED(status) &&
-                ((WSTOPSIG(status) == SIGVTALRM) ||
-                 /* running UML inside a detached screen can cause
-                  * SIGWINCHes
-                  */
-                 (WSTOPSIG(status) == SIGWINCH)));
-
-        if((n < 0) || !WIFSTOPPED(status) ||
-           (WSTOPSIG(status) != SIGUSR1 && WSTOPSIG(status) != SIGTRAP)){
-                unsigned long regs[MAX_REG_NR];
-
-                if(ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
-                        printk("Failed to get registers from stub, "
-                               "errno = %d\n", errno);
-                else {
-                        int i;
-
-                        printk("Stub registers -\n");
-                        for(i = 0; i < ARRAY_SIZE(regs); i++)
-                                printk("\t%d - %lx\n", i, regs[i]);
-                }
-                panic("%s : failed to wait for SIGUSR1/SIGTRAP, "
-                      "pid = %d, n = %d, errno = %d, status = 0x%x\n",
-                      fname, pid, n, errno, status);
+                if((n < 0) || !WIFSTOPPED(status))
+                        goto bad_wait;
+
+                if(((1 << WSTOPSIG(status)) & STUB_SIG_MASK) == 0)
+                        break;
+
+                err = ptrace(PTRACE_CONT, pid, 0, 0);
+                if(err)
+                        panic("wait_stub_done : continue failed, errno = %d\n",
+                              errno);
         }
+
+        if(((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0)
+                return;
+
+bad_wait:
+        err = ptrace_dump_regs(pid);
+        if(err)
+                printk("Failed to get registers from stub, errno = %d\n", -err);
+        panic("wait_stub_done : failed to wait for SIGUSR1/SIGTRAP, pid = %d, "
+              "n = %d, errno = %d, status = 0x%x\n", pid, n, errno, status);
 }
 
 extern unsigned long current_stub_stack(void);
@@ -104,7 +118,11 @@ void get_skas_faultinfo(int pid, struct faultinfo * fi)
                                sizeof(struct ptrace_faultinfo));
         }
         else {
-                wait_stub_done(pid, SIGSEGV, "get_skas_faultinfo");
+                err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV);
+                if(err)
+                        panic("Failed to continue stub, pid = %d, errno = %d\n",
+                              pid, errno);
+                wait_stub_done(pid);
 
                 /* faultinfo is prepared by the stub-segv-handler at start of
                  * the stub stack page. We just have to copy it.
@@ -142,9 +160,14 @@ static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu
 
                 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
                 if((err < 0) || !WIFSTOPPED(status) ||
-                   (WSTOPSIG(status) != SIGTRAP + 0x80))
+                   (WSTOPSIG(status) != SIGTRAP + 0x80)){
+                        err = ptrace_dump_regs(pid);
+                        if(err)
+                                printk("Failed to get registers from process, "
+                                       "errno = %d\n", -err);
                         panic("handle_trap - failed to wait at end of syscall, "
                               "errno = %d, status = %d\n", errno, status);
+                }
         }
 
         handle_syscall(regs);
@@ -172,7 +195,7 @@ static int userspace_tramp(void *stack)
                 int fd;
                 __u64 offset;
                 fd = phys_mapping(to_phys(&__syscall_stub_start), &offset);
-                addr = mmap64((void *) UML_CONFIG_STUB_CODE, page_size(),
+                addr = mmap64((void *) UML_CONFIG_STUB_CODE, UM_KERN_PAGE_SIZE,
                               PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
                 if(addr == MAP_FAILED){
                         printk("mapping mmap stub failed, errno = %d\n",
@@ -182,8 +205,8 @@ static int userspace_tramp(void *stack)
 
                 if(stack != NULL){
                         fd = phys_mapping(to_phys(stack), &offset);
-                        addr = mmap((void *) UML_CONFIG_STUB_DATA, page_size(),
-                                    PROT_READ | PROT_WRITE,
+                        addr = mmap((void *) UML_CONFIG_STUB_DATA,
+                                    UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
                                     MAP_FIXED | MAP_SHARED, fd, offset);
                         if(addr == MAP_FAILED){
                                 printk("mapping segfault stack failed, "
@@ -199,7 +222,7 @@ static int userspace_tramp(void *stack)
                                   (unsigned long) stub_segv_handler -
                                   (unsigned long) &__syscall_stub_start;
 
-                set_sigstack((void *) UML_CONFIG_STUB_DATA, page_size());
+                set_sigstack((void *) UML_CONFIG_STUB_DATA, UM_KERN_PAGE_SIZE);
                 sigemptyset(&sa.sa_mask);
                 sigaddset(&sa.sa_mask, SIGIO);
                 sigaddset(&sa.sa_mask, SIGWINCH);
@@ -291,10 +314,13 @@ void userspace(union uml_pt_regs *regs)
                 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
 
                 if(WIFSTOPPED(status)){
-                        switch(WSTOPSIG(status)){
+                        int sig = WSTOPSIG(status);
+                        switch(sig){
                         case SIGSEGV:
-                                if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo)
-                                        user_signal(SIGSEGV, regs, pid);
+                                if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo){
+                                        get_skas_faultinfo(pid, &regs->skas.faultinfo);
+                                        (*sig_info[SIGSEGV])(SIGSEGV, regs);
+                                }
                                 else handle_segv(pid, regs);
                                 break;
                         case SIGTRAP + 0x80:
@@ -309,11 +335,13 @@ void userspace(union uml_pt_regs *regs)
                         case SIGBUS:
                         case SIGFPE:
                         case SIGWINCH:
-                                user_signal(WSTOPSIG(status), regs, pid);
+                                block_signals();
+                                (*sig_info[sig])(sig, regs);
+                                unblock_signals();
                                 break;
                         default:
                                 printk("userspace - child stopped with signal "
-                                       "%d\n", WSTOPSIG(status));
+                                       "%d\n", sig);
                         }
                         pid = userspace_pid[0];
                         interrupt_end();
@@ -325,11 +353,29 @@ void userspace(union uml_pt_regs *regs)
         }
 }
 
+static unsigned long thread_regs[MAX_REG_NR];
+static unsigned long thread_fp_regs[HOST_FP_SIZE];
+
+static int __init init_thread_regs(void)
+{
+        get_safe_registers(thread_regs, thread_fp_regs);
+        /* Set parent's instruction pointer to start of clone-stub */
+        thread_regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
+                                (unsigned long) stub_clone_handler -
+                                (unsigned long) &__syscall_stub_start;
+        thread_regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE -
+                sizeof(void *);
+#ifdef __SIGNAL_FRAMESIZE
+        thread_regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
+#endif
+        return 0;
+}
+
+__initcall(init_thread_regs);
+
 int copy_context_skas0(unsigned long new_stack, int pid)
 {
         int err;
-        unsigned long regs[MAX_REG_NR];
-        unsigned long fp_regs[HOST_FP_SIZE];
         unsigned long current_stack = current_stub_stack();
         struct stub_data *data = (struct stub_data *) current_stack;
         struct stub_data *child_data = (struct stub_data *) new_stack;
@@ -344,23 +390,12 @@ int copy_context_skas0(unsigned long new_stack, int pid)
                                       .timer    = ((struct itimerval)
                                                     { { 0, 1000000 / hz() },
                                                       { 0, 1000000 / hz() }})});
-        get_safe_registers(regs, fp_regs);
-
-        /* Set parent's instruction pointer to start of clone-stub */
-        regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
-                                (unsigned long) stub_clone_handler -
-                                (unsigned long) &__syscall_stub_start;
-        regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE -
-                sizeof(void *);
-#ifdef __SIGNAL_FRAMESIZE
-        regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
-#endif
-        err = ptrace_setregs(pid, regs);
+        err = ptrace_setregs(pid, thread_regs);
         if(err < 0)
                 panic("copy_context_skas0 : PTRACE_SETREGS failed, "
                       "pid = %d, errno = %d\n", pid, -err);
 
-        err = ptrace_setfpregs(pid, fp_regs);
+        err = ptrace_setfpregs(pid, thread_fp_regs);
         if(err < 0)
                 panic("copy_context_skas0 : PTRACE_SETFPREGS failed, "
                       "pid = %d, errno = %d\n", pid, -err);
@@ -371,7 +406,11 @@ int copy_context_skas0(unsigned long new_stack, int pid)
         /* Wait, until parent has finished its work: read child's pid from
          * parent's stack, and check, if bad result.
          */
-        wait_stub_done(pid, 0, "copy_context_skas0");
+        err = ptrace(PTRACE_CONT, pid, 0, 0);
+        if(err)
+                panic("Failed to continue new process, pid = %d, "
+                      "errno = %d\n", pid, errno);
+        wait_stub_done(pid);
 
         pid = data->err;
         if(pid < 0)
@@ -381,7 +420,7 @@ int copy_context_skas0(unsigned long new_stack, int pid)
         /* Wait, until child has finished too: read child's result from
          * child's stack and check it.
          */
-        wait_stub_done(pid, -1, "copy_context_skas0");
+        wait_stub_done(pid);
         if (child_data->err != UML_CONFIG_STUB_DATA)
                 panic("copy_context_skas0 - stub-child reports error %ld\n",
                       child_data->err);
@@ -396,7 +435,7 @@ int copy_context_skas0(unsigned long new_stack, int pid)
 
 /*
  * This is used only, if stub pages are needed, while proc_mm is
- * availabl. Opening /proc/mm creates a new mm_context, which lacks
+ * available. Opening /proc/mm creates a new mm_context, which lacks
  * the stub-pages. Thus, we map them using /proc/mm-fd
  */
 void map_stub_pages(int fd, unsigned long code,
@@ -418,12 +457,13 @@ void map_stub_pages(int fd, unsigned long code,
                                           .fd      = code_fd,
                                           .offset  = code_offset
         } } });
-        n = os_write_file(fd, &mmop, sizeof(mmop));
+        CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop)));
         if(n != sizeof(mmop)){
+                n = errno;
                 printk("mmap args - addr = 0x%lx, fd = %d, offset = %llx\n",
                        code, code_fd, (unsigned long long) code_offset);
                 panic("map_stub_pages : /proc/mm map for code failed, "
-                      "err = %d\n", -n);
+                      "err = %d\n", n);
         }
 
         if ( stack ) {
@@ -440,10 +480,10 @@ void map_stub_pages(int fd, unsigned long code,
                                       .fd      = map_fd,
                                       .offset  = map_offset
                 } } });
-                n = os_write_file(fd, &mmop, sizeof(mmop));
+                CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop)));
                 if(n != sizeof(mmop))
                         panic("map_stub_pages : /proc/mm map for data failed, "
-                              "err = %d\n", -n);
+                              "err = %d\n", errno);
         }
 }
 
@@ -480,7 +520,15 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf)
                     SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM,
                     SIGVTALRM, -1);
 
-        n = UML_SETJMP(&initial_jmpbuf);
+        /*
+         * Can't use UML_SETJMP or UML_LONGJMP here because they save
+         * and restore signals, with the possible side-effect of
+         * trying to handle any signals which came when they were
+         * blocked, which can't be done on this stack.
+         * Signals must be blocked when jumping back here and restored
+         * after returning to the jumper.
+         */
+        n = setjmp(initial_jmpbuf);
         switch(n){
         case INIT_JMP_NEW_THREAD:
                 (*switch_buf)[0].JB_IP = (unsigned long) new_thread_handler;
@@ -490,7 +538,7 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf)
                 break;
         case INIT_JMP_CALLBACK:
                 (*cb_proc)(cb_arg);
-                UML_LONGJMP(cb_back, 1);
+                longjmp(*cb_back, 1);
                 break;
         case INIT_JMP_HALT:
                 kmalloc_ok = 0;
@@ -501,7 +549,7 @@ int start_idle_thread(void *stack, jmp_buf *switch_buf)
         default:
                 panic("Bad sigsetjmp return in start_idle_thread - %d\n", n);
         }
-        UML_LONGJMP(switch_buf, 1);
+        longjmp(*switch_buf, 1);
 }
 
 void initial_thread_cb_skas(void (*proc)(void *), void *arg)
diff --git a/arch/um/os-Linux/skas/trap.c b/arch/um/os-Linux/skas/trap.c
index 9ad5fbec4593..3b600c2e63b8 100644
--- a/arch/um/os-Linux/skas/trap.c
+++ b/arch/um/os-Linux/skas/trap.c
@@ -5,8 +5,8 @@
 
 #include <signal.h>
 #include <errno.h>
-#include "user_util.h"
 #include "kern_util.h"
+#include "as-layout.h"
 #include "task.h"
 #include "sigcontext.h"
 #include "skas.h"
@@ -15,29 +15,39 @@
 #include "sysdep/ptrace_user.h"
 #include "os.h"
 
+static union uml_pt_regs ksig_regs[UM_NR_CPUS];
+
 void sig_handler_common_skas(int sig, void *sc_ptr)
 {
         struct sigcontext *sc = sc_ptr;
-        struct skas_regs *r;
+        union uml_pt_regs *r;
         void (*handler)(int, union uml_pt_regs *);
-        int save_errno = errno;
-        int save_user;
+        int save_user, save_errno = errno;
 
         /* This is done because to allow SIGSEGV to be delivered inside a SEGV
          * handler.  This can happen in copy_user, and if SEGV is disabled,
          * the process will die.
          * XXX Figure out why this is better than SA_NODEFER
          */
-        if(sig == SIGSEGV)
+        if(sig == SIGSEGV) {
                 change_sig(SIGSEGV, 1);
+                /* For segfaults, we want the data from the
+                 * sigcontext.  In this case, we don't want to mangle
+                 * the process registers, so use a static set of
+                 * registers.  For other signals, the process
+                 * registers are OK.
+                 */
+                r = &ksig_regs[cpu()];
+                copy_sc(r, sc_ptr);
+        }
+        else r = TASK_REGS(get_current());
 
-        r = &TASK_REGS(get_current())->skas;
-        save_user = r->is_user;
-        r->is_user = 0;
+        save_user = r->skas.is_user;
+        r->skas.is_user = 0;
         if ( sig == SIGFPE || sig == SIGSEGV ||
              sig == SIGBUS || sig == SIGILL ||
              sig == SIGTRAP ) {
-                GET_FAULTINFO_FROM_SC(r->faultinfo, sc);
+                GET_FAULTINFO_FROM_SC(r->skas.faultinfo, sc);
         }
 
         change_sig(SIGUSR1, 1);
@@ -49,25 +59,8 @@ void sig_handler_common_skas(int sig, void *sc_ptr)
             sig != SIGVTALRM && sig != SIGALRM)
                 unblock_signals();
 
-        handler(sig, (union uml_pt_regs *) r);
+        handler(sig, r);
 
         errno = save_errno;
-        r->is_user = save_user;
-}
-
-extern int ptrace_faultinfo;
-
-void user_signal(int sig, union uml_pt_regs *regs, int pid)
-{
-        void (*handler)(int, union uml_pt_regs *);
-        int segv = ((sig == SIGFPE) || (sig == SIGSEGV) || (sig == SIGBUS) ||
-                    (sig == SIGILL) || (sig == SIGTRAP));
-
-        if (segv)
-                get_skas_faultinfo(pid, &regs->skas.faultinfo);
-
-        handler = sig_info[sig];
-        handler(sig, (union uml_pt_regs *) regs);
-
-        unblock_signals();
+        r->skas.is_user = save_user;
 }
diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c
index 5178eba9afa5..79471f85eb89 100644
--- a/arch/um/os-Linux/start_up.c
+++ b/arch/um/os-Linux/start_up.c
@@ -17,10 +17,10 @@
 #include <sys/time.h>
 #include <sys/wait.h>
 #include <sys/mman.h>
+#include <sys/resource.h>
 #include <asm/unistd.h>
 #include <asm/page.h>
 #include <sys/types.h>
-#include "user_util.h"
 #include "kern_util.h"
 #include "user.h"
 #include "signal_kern.h"
@@ -329,8 +329,32 @@ static void __init check_ptrace(void)
 
 extern void check_tmpexec(void);
 
-void os_early_checks(void)
+static void __init check_coredump_limit(void)
 {
+        struct rlimit lim;
+        int err = getrlimit(RLIMIT_CORE, &lim);
+
+        if(err){
+                perror("Getting core dump limit");
+                return;
+        }
+
+        printf("Core dump limits :\n\tsoft - ");
+        if(lim.rlim_cur == RLIM_INFINITY)
+                printf("NONE\n");
+        else printf("%lu\n", lim.rlim_cur);
+
+        printf("\thard - ");
+        if(lim.rlim_max == RLIM_INFINITY)
+                printf("NONE\n");
+        else printf("%lu\n", lim.rlim_max);
+}
+
+void __init os_early_checks(void)
+{
+        /* Print out the core dump limits early */
+        check_coredump_limit();
+
         check_ptrace();
 
         /* Need to check this early because mmapping happens before the
@@ -528,148 +552,3 @@ int __init parse_iomem(char *str, int *add)
  out:
         return 1;
 }
-
-
-/* Changed during early boot */
-int pty_output_sigio = 0;
-int pty_close_sigio = 0;
-
-/* Used as a flag during SIGIO testing early in boot */
-static volatile int got_sigio = 0;
-
-static void __init handler(int sig)
-{
-        got_sigio = 1;
-}
-
-struct openpty_arg {
-        int master;
-        int slave;
-        int err;
-};
-
-static void openpty_cb(void *arg)
-{
-        struct openpty_arg *info = arg;
-
-        info->err = 0;
-        if(openpty(&info->master, &info->slave, NULL, NULL, NULL))
-                info->err = -errno;
-}
-
-static int async_pty(int master, int slave)
-{
-        int flags;
-
-        flags = fcntl(master, F_GETFL);
-        if(flags < 0)
-                return -errno;
-
-        if((fcntl(master, F_SETFL, flags | O_NONBLOCK | O_ASYNC) < 0) ||
-           (fcntl(master, F_SETOWN, os_getpid()) < 0))
-                return -errno;
-
-        if((fcntl(slave, F_SETFL, flags | O_NONBLOCK) < 0))
-                return -errno;
-
-        return(0);
-}
-
-static void __init check_one_sigio(void (*proc)(int, int))
-{
-        struct sigaction old, new;
-        struct openpty_arg pty = { .master = -1, .slave = -1 };
-        int master, slave, err;
-
-        initial_thread_cb(openpty_cb, &pty);
-        if(pty.err){
-                printk("openpty failed, errno = %d\n", -pty.err);
-                return;
-        }
-
-        master = pty.master;
-        slave = pty.slave;
-
-        if((master == -1) || (slave == -1)){
-                printk("openpty failed to allocate a pty\n");
-                return;
-        }
-
-        /* Not now, but complain so we now where we failed. */
-        err = raw(master);
-        if (err < 0)
-                panic("check_sigio : __raw failed, errno = %d\n", -err);
-
-        err = async_pty(master, slave);
-        if(err < 0)
-                panic("tty_fds : sigio_async failed, err = %d\n", -err);
-
-        if(sigaction(SIGIO, NULL, &old) < 0)
-                panic("check_sigio : sigaction 1 failed, errno = %d\n", errno);
-        new = old;
-        new.sa_handler = handler;
-        if(sigaction(SIGIO, &new, NULL) < 0)
-                panic("check_sigio : sigaction 2 failed, errno = %d\n", errno);
-
-        got_sigio = 0;
-        (*proc)(master, slave);
-
-        close(master);
-        close(slave);
-
-        if(sigaction(SIGIO, &old, NULL) < 0)
-                panic("check_sigio : sigaction 3 failed, errno = %d\n", errno);
-}
-
-static void tty_output(int master, int slave)
-{
-        int n;
-        char buf[512];
-
-        printk("Checking that host ptys support output SIGIO...");
-
-        memset(buf, 0, sizeof(buf));
-
-        while(os_write_file(master, buf, sizeof(buf)) > 0) ;
-        if(errno != EAGAIN)
-                panic("check_sigio : write failed, errno = %d\n", errno);
-        while(((n = os_read_file(slave, buf, sizeof(buf))) > 0) && !got_sigio) ;
-
-        if(got_sigio){
-                printk("Yes\n");
-                pty_output_sigio = 1;
-        }
-        else if(n == -EAGAIN) printk("No, enabling workaround\n");
-        else panic("check_sigio : read failed, err = %d\n", n);
-}
-
-static void tty_close(int master, int slave)
-{
-        printk("Checking that host ptys support SIGIO on close...");
-
-        close(slave);
-        if(got_sigio){
-                printk("Yes\n");
-                pty_close_sigio = 1;
-        }
-        else printk("No, enabling workaround\n");
-}
-
-void __init check_sigio(void)
-{
-        if((os_access("/dev/ptmx", OS_ACC_R_OK) < 0) &&
-           (os_access("/dev/ptyp0", OS_ACC_R_OK) < 0)){
-                printk("No pseudo-terminals available - skipping pty SIGIO "
-                       "check\n");
-                return;
-        }
-        check_one_sigio(tty_output);
-        check_one_sigio(tty_close);
-}
-
-void os_check_bugs(void)
-{
-        check_ptrace();
-        check_sigio();
-}
-
diff --git a/arch/um/os-Linux/sys-i386/tls.c b/arch/um/os-Linux/sys-i386/tls.c
index 256532034c62..32ed41ec1a3d 100644
--- a/arch/um/os-Linux/sys-i386/tls.c
+++ b/arch/um/os-Linux/sys-i386/tls.c
@@ -5,7 +5,7 @@
 #include <unistd.h>
 
 #include "sysdep/tls.h"
-#include "user_util.h"
+#include "user.h"
 
 /* Checks whether host supports TLS, and sets *tls_min according to the value
  * valid on the host.
diff --git a/arch/um/os-Linux/time.c b/arch/um/os-Linux/time.c
index 2115b8beb541..5de169b168f6 100644
--- a/arch/um/os-Linux/time.c
+++ b/arch/um/os-Linux/time.c
@@ -10,7 +10,6 @@
 #include <sys/time.h>
 #include <signal.h>
 #include <errno.h>
-#include "user_util.h"
 #include "kern_util.h"
 #include "user.h"
 #include "process.h"
diff --git a/arch/um/os-Linux/trap.c b/arch/um/os-Linux/trap.c
index d221214d2ed5..295da657931a 100644
--- a/arch/um/os-Linux/trap.c
+++ b/arch/um/os-Linux/trap.c
@@ -6,7 +6,6 @@
 #include <stdlib.h>
 #include <signal.h>
 #include "kern_util.h"
-#include "user_util.h"
 #include "os.h"
 #include "mode.h"
 #include "longjmp.h"
diff --git a/arch/um/os-Linux/tt.c b/arch/um/os-Linux/tt.c
index 3dc3a02d6263..bcf9359c4e9f 100644
--- a/arch/um/os-Linux/tt.c
+++ b/arch/um/os-Linux/tt.c
@@ -18,7 +18,6 @@
 #include <asm/ptrace.h>
 #include <asm/unistd.h>
 #include <asm/page.h>
-#include "user_util.h"
 #include "kern_util.h"
 #include "user.h"
 #include "signal_kern.h"
@@ -32,6 +31,7 @@
 #include "choose-mode.h"
 #include "mode.h"
 #include "tempfile.h"
+#include "kern_constants.h"
 
 int protect_memory(unsigned long addr, unsigned long len, int r, int w, int x,
                    int must_succeed)
@@ -143,7 +143,7 @@ int outer_tramp(void *arg)
         int sig = sigkill;
 
         t = arg;
-        t->pid = clone(t->tramp, (void *) t->temp_stack + page_size()/2,
+        t->pid = clone(t->tramp, (void *) t->temp_stack + UM_KERN_PAGE_SIZE/2,
                        t->flags, t->tramp_data);
         if(t->pid > 0) wait_for_stop(t->pid, SIGSTOP, PTRACE_CONT, NULL);
         kill(os_getpid(), sig);
diff --git a/arch/um/os-Linux/tty_log.c b/arch/um/os-Linux/tty_log.c
index c6ba56c1560f..d11a55baa6bd 100644
--- a/arch/um/os-Linux/tty_log.c
+++ b/arch/um/os-Linux/tty_log.c
@@ -53,9 +53,9 @@ int open_tty_log(void *tty, void *current_tty)
                                                .direction = 0,
                                                .sec = tv.tv_sec,
                                                .usec = tv.tv_usec } );
-                os_write_file(tty_log_fd, &data, sizeof(data));
-                os_write_file(tty_log_fd, &current_tty, data.len);
-                return(tty_log_fd);
+                write(tty_log_fd, &data, sizeof(data));
+                write(tty_log_fd, &current_tty, data.len);
+                return tty_log_fd;
         }
 
         sprintf(buf, "%s/%0u-%0u", tty_log_dir, (unsigned int) tv.tv_sec,
@@ -67,7 +67,7 @@ int open_tty_log(void *tty, void *current_tty)
                 printk("open_tty_log : couldn't open '%s', errno = %d\n",
                        buf, -fd);
         }
-        return(fd);
+        return fd;
 }
 
 void close_tty_log(int fd, void *tty)
@@ -83,7 +83,7 @@ void close_tty_log(int fd, void *tty)
                                                .direction = 0,
                                                .sec = tv.tv_sec,
                                                .usec = tv.tv_usec } );
-                os_write_file(tty_log_fd, &data, sizeof(data));
+                write(tty_log_fd, &data, sizeof(data));
                 return;
         }
         os_close_file(fd);
@@ -98,21 +98,21 @@ static int log_chunk(int fd, const char *buf, int len)
                 try = (len > sizeof(chunk)) ? sizeof(chunk) : len;
                 missed = copy_from_user_proc(chunk, (char *) buf, try);
                 try -= missed;
-                n = os_write_file(fd, chunk, try);
+                n = write(fd, chunk, try);
                 if(n != try) {
                         if(n < 0)
-                                return(n);
-                        return(-EIO);
+                                return -errno;
+                        return -EIO;
                 }
                 if(missed != 0)
-                        return(-EFAULT);
+                        return -EFAULT;
 
                 len -= try;
                 total += try;
                 buf += try;
         }
 
-        return(total);
+        return total;
 }
 
 int write_tty_log(int fd, const char *buf, int len, void *tty, int is_read)
@@ -130,10 +130,10 @@ int write_tty_log(int fd, const char *buf, int len, void *tty, int is_read)
                                                .direction = direction,
                                                .sec = tv.tv_sec,
                                                .usec = tv.tv_usec } );
-                os_write_file(tty_log_fd, &data, sizeof(data));
+                write(tty_log_fd, &data, sizeof(data));
         }
 
-        return(log_chunk(fd, buf, len));
+        return log_chunk(fd, buf, len);
 }
 
 void log_exec(char **argv, void *tty)
@@ -161,7 +161,7 @@ void log_exec(char **argv, void *tty)
                                        .direction = 0,
                                        .sec = tv.tv_sec,
                                        .usec = tv.tv_usec } );
-        os_write_file(tty_log_fd, &data, sizeof(data));
+        write(tty_log_fd, &data, sizeof(data));
 
         for(ptr = argv; ; ptr++){
                 if(copy_from_user_proc(&arg, ptr, sizeof(arg)))
@@ -179,7 +179,7 @@ extern void register_tty_logger(int (*opener)(void *, void *),
 static int register_logger(void)
 {
         register_tty_logger(open_tty_log, write_tty_log, close_tty_log);
-        return(0);
+        return 0;
 }
 
 __uml_initcall(register_logger);
diff --git a/arch/um/os-Linux/util.c b/arch/um/os-Linux/util.c
index 56b8a50e8bc2..c307a89ed259 100644
--- a/arch/um/os-Linux/util.c
+++ b/arch/um/os-Linux/util.c
@@ -21,7 +21,6 @@
 #include <sched.h>
 #include <termios.h>
 #include <string.h>
-#include "user_util.h"
 #include "kern_util.h"
 #include "user.h"
 #include "mem_user.h"
@@ -30,28 +29,29 @@
 #include "uml-config.h"
 #include "os.h"
 #include "longjmp.h"
+#include "kern_constants.h"
 
 void stack_protections(unsigned long address)
 {
         int prot = PROT_READ | PROT_WRITE | PROT_EXEC;
 
-        if(mprotect((void *) address, page_size(), prot) < 0)
+        if(mprotect((void *) address, UM_KERN_PAGE_SIZE, prot) < 0)
                 panic("protecting stack failed, errno = %d", errno);
 }
 
 void task_protections(unsigned long address)
 {
-        unsigned long guard = address + page_size();
-        unsigned long stack = guard + page_size();
+        unsigned long guard = address + UM_KERN_PAGE_SIZE;
+        unsigned long stack = guard + UM_KERN_PAGE_SIZE;
         int prot = 0, pages;
 
 #ifdef notdef
-        if(mprotect((void *) stack, page_size(), prot) < 0)
+        if(mprotect((void *) stack, UM_KERN_PAGE_SIZE, prot) < 0)
                 panic("protecting guard page failed, errno = %d", errno);
 #endif
         pages = (1 << UML_CONFIG_KERNEL_STACK_ORDER) - 2;
         prot = PROT_READ | PROT_WRITE | PROT_EXEC;
-        if(mprotect((void *) stack, pages * page_size(), prot) < 0)
+        if(mprotect((void *) stack, pages * UM_KERN_PAGE_SIZE, prot) < 0)
                 panic("protecting stack failed, errno = %d", errno);
 }
 
@@ -96,15 +96,13 @@ void setup_machinename(char *machine_out)
         strcpy(machine_out, host.machine);
 }
 
-char host_info[(_UTSNAME_LENGTH + 1) * 4 + _UTSNAME_NODENAME_LENGTH + 1];
-
-void setup_hostinfo(void)
+void setup_hostinfo(char *buf, int len)
 {
         struct utsname host;
 
         uname(&host);
-        sprintf(host_info, "%s %s %s %s %s", host.sysname, host.nodename,
-                host.release, host.version, host.machine);
+        snprintf(buf, len, "%s %s %s %s %s", host.sysname, host.nodename,
+                 host.release, host.version, host.machine);
 }
 
 int setjmp_wrapper(void (*proc)(void *, void *), ...)
@@ -121,3 +119,9 @@ int setjmp_wrapper(void (*proc)(void *, void *), ...)
         va_end(args);
         return n;
 }
+
+void os_dump_core(void)
+{
+        signal(SIGSEGV, SIG_DFL);
+        abort();
+}