I realized that the best way to get the sys_time/sys_stime problem fixed is
to make sys_time 64 bit safe by using "time_t *" instead of "int *" and to
introduce two proper compat functions compat_sys_time and compat_sys_stime.

The prototype change of sys_time is transparent for 32 bit architectures
because both "int" and "time_t" are 32 bit.  For 64 bit the type change
would be wrong but luckily no 64 bit architecture uses sys_time/sys_stime
in 64 bit mode.  The patch makes the following change:

ia64     : Remove sys32_time, use compat_sys_time and
           add (!!) compat_sys_stime to compat syscall table.
mips     : Use compat_sys_time/compat_sys_stime in 32 bit syscall table.
           Add #ifdef magic to compile sys_time/sys_stime and
           compat_sys_time/compat_sys_stime only if needed.
parisc   : Remove sys32_time, use compat_sys_time and compat_sys_stime.
ppc64    : remove sys32_time, ppc64_sys32_stime and ppc64_sys_stime.
           Use common compat_sys_time, compat_sys_stime and sys_stime.
s390     : Use compat_sys_stime. Add #ifdef magic to compile
           sys_time/sys_stime and compat_sys_time/compat_sys_stime only
           if needed.
sparc64  : Use compat_sys_time/compat_Sys_stime in 32 bit syscall table.
um       : Remove um_time and um_stime. Use common functions sys_time and
           sys_stime. This adds a CAP_SYS_TIME check to UMs stime call.
x86_64   : Remove sys32_time. Use compat_sys_time and compat_sys_stime
           in 32 bit syscall table.

The original stime bug is fixed for mips, parisc, s390, sparc64 and
x86_64. Can the arch-maintainers please take a look at this?

From: Martin Schwidefsky <schwidefsky@de.ibm.com>

Convert compat_time_t to time_t in 32 bit emulation for sys_stime and
consolidate all the different implementation of sys_time, sys_stime and
their 32-bit emulation parts.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>