blob: b061c9aa6302f4b348b3f689d19f2f39e32df621 [file] [log] [blame]
/*
* Conversion between 32-bit and 64-bit native system calls.
*
* Copyright (C) 2000 Silicon Graphics, Inc.
* Written by Ulf Carlsson (ulfc@engr.sgi.com)
* sys32_execve from ia64/ia32 code, Feb 2000, Kanoj Sarcar (kanoj@sgi.com)
*/
#include <linux/compiler.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/smp_lock.h>
#include <linux/highuid.h>
#include <linux/dirent.h>
#include <linux/resource.h>
#include <linux/highmem.h>
#include <linux/time.h>
#include <linux/times.h>
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/filter.h>
#include <linux/shm.h>
#include <linux/sem.h>
#include <linux/msg.h>
#include <linux/icmpv6.h>
#include <linux/syscalls.h>
#include <linux/sysctl.h>
#include <linux/utime.h>
#include <linux/utsname.h>
#include <linux/personality.h>
#include <linux/dnotify.h>
#include <linux/module.h>
#include <linux/binfmts.h>
#include <linux/security.h>
#include <linux/compat.h>
#include <linux/vfs.h>
#include <net/sock.h>
#include <net/scm.h>
#include <asm/ipc.h>
#include <asm/sim.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/mman.h>
/* Use this to get at 32-bit user passed pointers. */
/* A() macro should be used for places where you e.g.
have some internal variable u32 and just want to get
rid of a compiler warning. AA() has to be used in
places where you want to convert a function argument
to 32bit pointer or when you e.g. access pt_regs
structure and want to consider 32bit registers only.
*/
#define A(__x) ((unsigned long)(__x))
#define AA(__x) ((unsigned long)((int)__x))
#ifdef __MIPSEB__
#define merge_64(r1,r2) ((((r1) & 0xffffffffUL) << 32) + ((r2) & 0xffffffffUL))
#endif
#ifdef __MIPSEL__
#define merge_64(r1,r2) ((((r2) & 0xffffffffUL) << 32) + ((r1) & 0xffffffffUL))
#endif
/*
* Revalidate the inode. This is required for proper NFS attribute caching.
*/
int cp_compat_stat(struct kstat *stat, struct compat_stat __user *statbuf)
{
struct compat_stat tmp;
if (!new_valid_dev(stat->dev) || !new_valid_dev(stat->rdev))
return -EOVERFLOW;
memset(&tmp, 0, sizeof(tmp));
tmp.st_dev = new_encode_dev(stat->dev);
tmp.st_ino = stat->ino;
if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
return -EOVERFLOW;
tmp.st_mode = stat->mode;
tmp.st_nlink = stat->nlink;
SET_UID(tmp.st_uid, stat->uid);
SET_GID(tmp.st_gid, stat->gid);
tmp.st_rdev = new_encode_dev(stat->rdev);
tmp.st_size = stat->size;
tmp.st_atime = stat->atime.tv_sec;
tmp.st_mtime = stat->mtime.tv_sec;
tmp.st_ctime = stat->ctime.tv_sec;
#ifdef STAT_HAVE_NSEC
tmp.st_atime_nsec = stat->atime.tv_nsec;
tmp.st_mtime_nsec = stat->mtime.tv_nsec;
tmp.st_ctime_nsec = stat->ctime.tv_nsec;
#endif
tmp.st_blocks = stat->blocks;
tmp.st_blksize = stat->blksize;
return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
}
asmlinkage unsigned long
sys32_mmap2(unsigned long addr, unsigned long len, unsigned long prot,
unsigned long flags, unsigned long fd, unsigned long pgoff)
{
struct file * file = NULL;
unsigned long error;
error = -EINVAL;
if (pgoff & (~PAGE_MASK >> 12))
goto out;
pgoff >>= PAGE_SHIFT-12;
if (!(flags & MAP_ANONYMOUS)) {
error = -EBADF;
file = fget(fd);
if (!file)
goto out;
}
flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
down_write(&current->mm->mmap_sem);
error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
up_write(&current->mm->mmap_sem);
if (file)
fput(file);
out:
return error;
}
asmlinkage int sys_truncate64(const char __user *path, unsigned int high,
unsigned int low)
{
if ((int)high < 0)
return -EINVAL;
return sys_truncate(path, ((long) high << 32) | low);
}
asmlinkage int sys_ftruncate64(unsigned int fd, unsigned int high,
unsigned int low)
{
if ((int)high < 0)
return -EINVAL;
return sys_ftruncate(fd, ((long) high << 32) | low);
}
/*
* sys_execve() executes a new program.
*/
asmlinkage int sys32_execve(nabi_no_regargs struct pt_regs regs)
{
int error;
char * filename;
filename = getname(compat_ptr(regs.regs[4]));
error = PTR_ERR(filename);
if (IS_ERR(filename))
goto out;
error = compat_do_execve(filename, compat_ptr(regs.regs[5]),
compat_ptr(regs.regs[6]), &regs);
putname(filename);
out:
return error;
}
asmlinkage long
sysn32_waitid(int which, compat_pid_t pid,
siginfo_t __user *uinfo, int options,
struct compat_rusage __user *uru)
{
struct rusage ru;
long ret;
mm_segment_t old_fs = get_fs();
int si_signo;
if (!access_ok(VERIFY_WRITE, uinfo, sizeof(*uinfo)))
return -EFAULT;
set_fs (KERNEL_DS);
ret = sys_waitid(which, pid, uinfo, options,
uru ? (struct rusage __user *) &ru : NULL);
set_fs (old_fs);
if (__get_user(si_signo, &uinfo->si_signo))
return -EFAULT;
if (ret < 0 || si_signo == 0)
return ret;
if (uru)
ret = put_compat_rusage(&ru, uru);
return ret;
}
struct sysinfo32 {
s32 uptime;
u32 loads[3];
u32 totalram;
u32 freeram;
u32 sharedram;
u32 bufferram;
u32 totalswap;
u32 freeswap;
u16 procs;
u32 totalhigh;
u32 freehigh;
u32 mem_unit;
char _f[8];
};
asmlinkage int sys32_sysinfo(struct sysinfo32 __user *info)
{
struct sysinfo s;
int ret, err;
mm_segment_t old_fs = get_fs ();
set_fs (KERNEL_DS);
ret = sys_sysinfo((struct sysinfo __user *)&s);
set_fs (old_fs);
err = put_user (s.uptime, &info->uptime);
err |= __put_user (s.loads[0], &info->loads[0]);
err |= __put_user (s.loads[1], &info->loads[1]);
err |= __put_user (s.loads[2], &info->loads[2]);
err |= __put_user (s.totalram, &info->totalram);
err |= __put_user (s.freeram, &info->freeram);
err |= __put_user (s.sharedram, &info->sharedram);
err |= __put_user (s.bufferram, &info->bufferram);
err |= __put_user (s.totalswap, &info->totalswap);
err |= __put_user (s.freeswap, &info->freeswap);
err |= __put_user (s.procs, &info->procs);
err |= __put_user (s.totalhigh, &info->totalhigh);
err |= __put_user (s.freehigh, &info->freehigh);
err |= __put_user (s.mem_unit, &info->mem_unit);
if (err)
return -EFAULT;
return ret;
}
#define RLIM_INFINITY32 0x7fffffff
#define RESOURCE32(x) ((x > RLIM_INFINITY32) ? RLIM_INFINITY32 : x)
struct rlimit32 {
int rlim_cur;
int rlim_max;
};
#ifdef __MIPSEB__
asmlinkage long sys32_truncate64(const char __user * path, unsigned long __dummy,
int length_hi, int length_lo)
#endif
#ifdef __MIPSEL__
asmlinkage long sys32_truncate64(const char __user * path, unsigned long __dummy,
int length_lo, int length_hi)
#endif
{
loff_t length;
length = ((unsigned long) length_hi << 32) | (unsigned int) length_lo;
return sys_truncate(path, length);
}
#ifdef __MIPSEB__
asmlinkage long sys32_ftruncate64(unsigned int fd, unsigned long __dummy,
int length_hi, int length_lo)
#endif
#ifdef __MIPSEL__
asmlinkage long sys32_ftruncate64(unsigned int fd, unsigned long __dummy,
int length_lo, int length_hi)
#endif
{
loff_t length;
length = ((unsigned long) length_hi << 32) | (unsigned int) length_lo;
return sys_ftruncate(fd, length);
}
static inline long
get_tv32(struct timeval *o, struct compat_timeval __user *i)
{
return (!access_ok(VERIFY_READ, i, sizeof(*i)) ||
(__get_user(o->tv_sec, &i->tv_sec) |
__get_user(o->tv_usec, &i->tv_usec)));
}
static inline long
put_tv32(struct compat_timeval __user *o, struct timeval *i)
{
return (!access_ok(VERIFY_WRITE, o, sizeof(*o)) ||
(__put_user(i->tv_sec, &o->tv_sec) |
__put_user(i->tv_usec, &o->tv_usec)));
}
extern struct timezone sys_tz;
asmlinkage int
sys32_gettimeofday(struct compat_timeval __user *tv, struct timezone __user *tz)
{
if (tv) {
struct timeval ktv;
do_gettimeofday(&ktv);
if (put_tv32(tv, &ktv))
return -EFAULT;
}
if (tz) {
if (copy_to_user(tz, &sys_tz, sizeof(sys_tz)))
return -EFAULT;
}
return 0;
}
static inline long get_ts32(struct timespec *o, struct compat_timeval __user *i)
{
long usec;
if (!access_ok(VERIFY_READ, i, sizeof(*i)))
return -EFAULT;
if (__get_user(o->tv_sec, &i->tv_sec))
return -EFAULT;
if (__get_user(usec, &i->tv_usec))
return -EFAULT;
o->tv_nsec = usec * 1000;
return 0;
}
asmlinkage int
sys32_settimeofday(struct compat_timeval __user *tv, struct timezone __user *tz)
{
struct timespec kts;
struct timezone ktz;
if (tv) {
if (get_ts32(&kts, tv))
return -EFAULT;
}
if (tz) {
if (copy_from_user(&ktz, tz, sizeof(ktz)))
return -EFAULT;
}
return do_sys_settimeofday(tv ? &kts : NULL, tz ? &ktz : NULL);
}
asmlinkage int sys32_llseek(unsigned int fd, unsigned int offset_high,
unsigned int offset_low, loff_t __user * result,
unsigned int origin)
{
return sys_llseek(fd, offset_high, offset_low, result, origin);
}
/* From the Single Unix Spec: pread & pwrite act like lseek to pos + op +
lseek back to original location. They fail just like lseek does on
non-seekable files. */
asmlinkage ssize_t sys32_pread(unsigned int fd, char __user * buf,
size_t count, u32 unused, u64 a4, u64 a5)
{
return sys_pread64(fd, buf, count, merge_64(a4, a5));
}
asmlinkage ssize_t sys32_pwrite(unsigned int fd, const char __user * buf,
size_t count, u32 unused, u64 a4, u64 a5)
{
return sys_pwrite64(fd, buf, count, merge_64(a4, a5));
}
asmlinkage int sys32_sched_rr_get_interval(compat_pid_t pid,
struct compat_timespec __user *interval)
{
struct timespec t;
int ret;
mm_segment_t old_fs = get_fs ();
set_fs (KERNEL_DS);
ret = sys_sched_rr_get_interval(pid, (struct timespec __user *)&t);
set_fs (old_fs);
if (put_user (t.tv_sec, &interval->tv_sec) ||
__put_user (t.tv_nsec, &interval->tv_nsec))
return -EFAULT;
return ret;
}
asmlinkage long
sys32_ipc (u32 call, int first, int second, int third, u32 ptr, u32 fifth)
{
int version, err;
version = call >> 16; /* hack for backward compatibility */
call &= 0xffff;
switch (call) {
case SEMOP:
/* struct sembuf is the same on 32 and 64bit :)) */
err = sys_semtimedop(first, compat_ptr(ptr), second, NULL);
break;
case SEMTIMEDOP:
err = compat_sys_semtimedop(first, compat_ptr(ptr), second,
compat_ptr(fifth));
break;
case SEMGET:
err = sys_semget(first, second, third);
break;
case SEMCTL:
err = compat_sys_semctl(first, second, third, compat_ptr(ptr));
break;
case MSGSND:
err = compat_sys_msgsnd(first, second, third, compat_ptr(ptr));
break;
case MSGRCV:
err = compat_sys_msgrcv(first, second, fifth, third,
version, compat_ptr(ptr));
break;
case MSGGET:
err = sys_msgget((key_t) first, second);
break;
case MSGCTL:
err = compat_sys_msgctl(first, second, compat_ptr(ptr));
break;
case SHMAT:
err = compat_sys_shmat(first, second, third, version,
compat_ptr(ptr));
break;
case SHMDT:
err = sys_shmdt(compat_ptr(ptr));
break;
case SHMGET:
err = sys_shmget(first, (unsigned)second, third);
break;
case SHMCTL:
err = compat_sys_shmctl(first, second, compat_ptr(ptr));
break;
default:
err = -EINVAL;
break;
}
return err;
}
#ifdef CONFIG_MIPS32_N32
asmlinkage long sysn32_semctl(int semid, int semnum, int cmd, union semun arg)
{
/* compat_sys_semctl expects a pointer to union semun */
u32 __user *uptr = compat_alloc_user_space(sizeof(u32));
if (put_user(ptr_to_compat(arg.__pad), uptr))
return -EFAULT;
return compat_sys_semctl(semid, semnum, cmd, uptr);
}
#endif
struct sysctl_args32
{
compat_caddr_t name;
int nlen;
compat_caddr_t oldval;
compat_caddr_t oldlenp;
compat_caddr_t newval;
compat_size_t newlen;
unsigned int __unused[4];
};
#ifdef CONFIG_SYSCTL_SYSCALL
asmlinkage long sys32_sysctl(struct sysctl_args32 __user *args)
{
struct sysctl_args32 tmp;
int error;
size_t oldlen;
size_t __user *oldlenp = NULL;
unsigned long addr = (((unsigned long)&args->__unused[0]) + 7) & ~7;
if (copy_from_user(&tmp, args, sizeof(tmp)))
return -EFAULT;
if (tmp.oldval && tmp.oldlenp) {
/* Duh, this is ugly and might not work if sysctl_args
is in read-only memory, but do_sysctl does indirectly
a lot of uaccess in both directions and we'd have to
basically copy the whole sysctl.c here, and
glibc's __sysctl uses rw memory for the structure
anyway. */
if (get_user(oldlen, (u32 __user *)A(tmp.oldlenp)) ||
put_user(oldlen, (size_t __user *)addr))
return -EFAULT;
oldlenp = (size_t __user *)addr;
}
lock_kernel();
error = do_sysctl((int __user *)A(tmp.name), tmp.nlen, (void __user *)A(tmp.oldval),
oldlenp, (void __user *)A(tmp.newval), tmp.newlen);
unlock_kernel();
if (oldlenp) {
if (!error) {
if (get_user(oldlen, (size_t __user *)addr) ||
put_user(oldlen, (u32 __user *)A(tmp.oldlenp)))
error = -EFAULT;
}
copy_to_user(args->__unused, tmp.__unused, sizeof(tmp.__unused));
}
return error;
}
#endif /* CONFIG_SYSCTL_SYSCALL */
asmlinkage long sys32_newuname(struct new_utsname __user * name)
{
int ret = 0;
down_read(&uts_sem);
if (copy_to_user(name, utsname(), sizeof *name))
ret = -EFAULT;
up_read(&uts_sem);
if (current->personality == PER_LINUX32 && !ret)
if (copy_to_user(name->machine, "mips\0\0\0", 8))
ret = -EFAULT;
return ret;
}
asmlinkage int sys32_personality(unsigned long personality)
{
int ret;
personality &= 0xffffffff;
if (personality(current->personality) == PER_LINUX32 &&
personality == PER_LINUX)
personality = PER_LINUX32;
ret = sys_personality(personality);
if (ret == PER_LINUX32)
ret = PER_LINUX;
return ret;
}
/* ustat compatibility */
struct ustat32 {
compat_daddr_t f_tfree;
compat_ino_t f_tinode;
char f_fname[6];
char f_fpack[6];
};
extern asmlinkage long sys_ustat(dev_t dev, struct ustat __user * ubuf);
asmlinkage int sys32_ustat(dev_t dev, struct ustat32 __user * ubuf32)
{
int err;
struct ustat tmp;
struct ustat32 tmp32;
mm_segment_t old_fs = get_fs();
set_fs(KERNEL_DS);
err = sys_ustat(dev, (struct ustat __user *)&tmp);
set_fs (old_fs);
if (err)
goto out;
memset(&tmp32,0,sizeof(struct ustat32));
tmp32.f_tfree = tmp.f_tfree;
tmp32.f_tinode = tmp.f_tinode;
err = copy_to_user(ubuf32,&tmp32,sizeof(struct ustat32)) ? -EFAULT : 0;
out:
return err;
}
asmlinkage int sys32_sendfile(int out_fd, int in_fd, compat_off_t __user *offset,
s32 count)
{
mm_segment_t old_fs = get_fs();
int ret;
off_t of;
if (offset && get_user(of, offset))
return -EFAULT;
set_fs(KERNEL_DS);
ret = sys_sendfile(out_fd, in_fd, offset ? (off_t __user *)&of : NULL, count);
set_fs(old_fs);
if (offset && put_user(of, offset))
return -EFAULT;
return ret;
}
asmlinkage ssize_t sys32_readahead(int fd, u32 pad0, u64 a2, u64 a3,
size_t count)
{
return sys_readahead(fd, merge_64(a2, a3), count);
}
asmlinkage long sys32_sync_file_range(int fd, int __pad,
unsigned long a2, unsigned long a3,
unsigned long a4, unsigned long a5,
int flags)
{
return sys_sync_file_range(fd,
merge_64(a2, a3), merge_64(a4, a5),
flags);
}
/* Argument list sizes for sys_socketcall */
#define AL(x) ((x) * sizeof(unsigned int))
static unsigned char socketcall_nargs[18]={AL(0),AL(3),AL(3),AL(3),AL(2),AL(3),
AL(3),AL(3),AL(4),AL(4),AL(4),AL(6),
AL(6),AL(2),AL(5),AL(5),AL(3),AL(3)};
#undef AL
/*
* System call vectors.
*
* Argument checking cleaned up. Saved 20% in size.
* This function doesn't need to set the kernel lock because
* it is set by the callees.
*/
asmlinkage long sys32_socketcall(int call, unsigned int __user *args32)
{
unsigned int a[6];
unsigned int a0,a1;
int err;
extern asmlinkage long sys_socket(int family, int type, int protocol);
extern asmlinkage long sys_bind(int fd, struct sockaddr __user *umyaddr, int addrlen);
extern asmlinkage long sys_connect(int fd, struct sockaddr __user *uservaddr, int addrlen);
extern asmlinkage long sys_listen(int fd, int backlog);
extern asmlinkage long sys_accept(int fd, struct sockaddr __user *upeer_sockaddr, int __user *upeer_addrlen);
extern asmlinkage long sys_getsockname(int fd, struct sockaddr __user *usockaddr, int __user *usockaddr_len);
extern asmlinkage long sys_getpeername(int fd, struct sockaddr __user *usockaddr, int __user *usockaddr_len);
extern asmlinkage long sys_socketpair(int family, int type, int protocol, int __user *usockvec);
extern asmlinkage long sys_send(int fd, void __user * buff, size_t len, unsigned flags);
extern asmlinkage long sys_sendto(int fd, void __user * buff, size_t len, unsigned flags,
struct sockaddr __user *addr, int addr_len);
extern asmlinkage long sys_recv(int fd, void __user * ubuf, size_t size, unsigned flags);
extern asmlinkage long sys_recvfrom(int fd, void __user * ubuf, size_t size, unsigned flags,
struct sockaddr __user *addr, int __user *addr_len);
extern asmlinkage long sys_shutdown(int fd, int how);
extern asmlinkage long sys_setsockopt(int fd, int level, int optname, char __user *optval, int optlen);
extern asmlinkage long sys_getsockopt(int fd, int level, int optname, char __user *optval, int __user *optlen);
extern asmlinkage long sys_sendmsg(int fd, struct msghdr __user *msg, unsigned flags);
extern asmlinkage long sys_recvmsg(int fd, struct msghdr __user *msg, unsigned int flags);
if(call<1||call>SYS_RECVMSG)
return -EINVAL;
/* copy_from_user should be SMP safe. */
if (copy_from_user(a, args32, socketcall_nargs[call]))
return -EFAULT;
a0=a[0];
a1=a[1];
switch(call)
{
case SYS_SOCKET:
err = sys_socket(a0,a1,a[2]);
break;
case SYS_BIND:
err = sys_bind(a0,(struct sockaddr __user *)A(a1), a[2]);
break;
case SYS_CONNECT:
err = sys_connect(a0, (struct sockaddr __user *)A(a1), a[2]);
break;
case SYS_LISTEN:
err = sys_listen(a0,a1);
break;
case SYS_ACCEPT:
err = sys_accept(a0,(struct sockaddr __user *)A(a1), (int __user *)A(a[2]));
break;
case SYS_GETSOCKNAME:
err = sys_getsockname(a0,(struct sockaddr __user *)A(a1), (int __user *)A(a[2]));
break;
case SYS_GETPEERNAME:
err = sys_getpeername(a0, (struct sockaddr __user *)A(a1), (int __user *)A(a[2]));
break;
case SYS_SOCKETPAIR:
err = sys_socketpair(a0,a1, a[2], (int __user *)A(a[3]));
break;
case SYS_SEND:
err = sys_send(a0, (void __user *)A(a1), a[2], a[3]);
break;
case SYS_SENDTO:
err = sys_sendto(a0,(void __user *)A(a1), a[2], a[3],
(struct sockaddr __user *)A(a[4]), a[5]);
break;
case SYS_RECV:
err = sys_recv(a0, (void __user *)A(a1), a[2], a[3]);
break;
case SYS_RECVFROM:
err = sys_recvfrom(a0, (void __user *)A(a1), a[2], a[3],
(struct sockaddr __user *)A(a[4]), (int __user *)A(a[5]));
break;
case SYS_SHUTDOWN:
err = sys_shutdown(a0,a1);
break;
case SYS_SETSOCKOPT:
err = sys_setsockopt(a0, a1, a[2], (char __user *)A(a[3]), a[4]);
break;
case SYS_GETSOCKOPT:
err = sys_getsockopt(a0, a1, a[2], (char __user *)A(a[3]), (int __user *)A(a[4]));
break;
case SYS_SENDMSG:
err = sys_sendmsg(a0, (struct msghdr __user *) A(a1), a[2]);
break;
case SYS_RECVMSG:
err = sys_recvmsg(a0, (struct msghdr __user *) A(a1), a[2]);
break;
default:
err = -EINVAL;
break;
}
return err;
}
struct sigevent32 {
u32 sigev_value;
u32 sigev_signo;
u32 sigev_notify;
u32 payload[(64 / 4) - 3];
};
extern asmlinkage long
sys_timer_create(clockid_t which_clock,
struct sigevent __user *timer_event_spec,
timer_t __user * created_timer_id);
long
sys32_timer_create(u32 clock, struct sigevent32 __user *se32, timer_t __user *timer_id)
{
struct sigevent __user *p = NULL;
if (se32) {
struct sigevent se;
p = compat_alloc_user_space(sizeof(struct sigevent));
memset(&se, 0, sizeof(struct sigevent));
if (get_user(se.sigev_value.sival_int, &se32->sigev_value) ||
__get_user(se.sigev_signo, &se32->sigev_signo) ||
__get_user(se.sigev_notify, &se32->sigev_notify) ||
__copy_from_user(&se._sigev_un._pad, &se32->payload,
sizeof(se32->payload)) ||
copy_to_user(p, &se, sizeof(se)))
return -EFAULT;
}
return sys_timer_create(clock, p, timer_id);
}
save_static_function(sys32_clone);
__attribute_used__ noinline static int
_sys32_clone(nabi_no_regargs struct pt_regs regs)
{
unsigned long clone_flags;
unsigned long newsp;
int __user *parent_tidptr, *child_tidptr;
clone_flags = regs.regs[4];
newsp = regs.regs[5];
if (!newsp)
newsp = regs.regs[29];
parent_tidptr = (int __user *) regs.regs[6];
/* Use __dummy4 instead of getting it off the stack, so that
syscall() works. */
child_tidptr = (int __user *) __dummy4;
return do_fork(clone_flags, newsp, &regs, 0,
parent_tidptr, child_tidptr);
}