[PATCH] x86_64: Fix 32bit system call restart

The test case at
http://cvs.sourceforge.net/viewcvs.py/posixtest/posixtestsuite/conforman
ce/interfaces/clock_nanosleep/1-5.c fails if it runs as a 32bit process on
x86_86 machines.

The root cause is the sub 32bit process fails to restart the syscall after it
is interrupted by a signal.

The syscall number of sys_restart_syscall in table sys_call_table is
__NR_restart_syscall (219) while it's __NR_ia32_restart_syscall
(0) in ia32_sys_call_table. When regs->rax==(unsigned
long)-ERESTART_RESTARTBLOCK, function do_signal doesn't distinguish if
the process is 64bit or 32bit, and always sets restart syscall number
as __NR_restart_syscall (219).

Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>