arm64: sanitize copy_thread(), switch to generic fork/vfork/clone

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/arm64/include/asm/syscalls.h

@@ -31,6 +31,8 @@ asmlinkage long sys_sigaltstack_wrapper(const stack_t __user *uss,
  * AArch64 sys_clone implementation has a different prototype than the generic
  * one (additional TLS value argument).
  */
+asmlinkage long sys_clone(unsigned long, unsigned long, void __user *, int,
+	       void __user *);
 #define sys_clone	sys_clone
 
 #include <asm-generic/syscalls.h>

arch/arm64/include/asm/unistd.h

@@ -24,6 +24,9 @@
 #define __ARCH_WANT_SYS_SIGPROCMASK
 #define __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND
 #define __ARCH_WANT_COMPAT_SYS_SENDFILE
+#define __ARCH_WANT_SYS_FORK
+#define __ARCH_WANT_SYS_VFORK
 #endif
 #define __ARCH_WANT_SYS_EXECVE
+#define __ARCH_WANT_SYS_CLONE
 #include <uapi/asm/unistd.h>

arch/arm64/include/asm/unistd32.h

@@ -23,7 +23,7 @@
 
 __SYSCALL(0,   sys_restart_syscall)
 __SYSCALL(1,   sys_exit)
-__SYSCALL(2,   compat_sys_fork)
+__SYSCALL(2,   sys_fork)
 __SYSCALL(3,   sys_read)
 __SYSCALL(4,   sys_write)
 __SYSCALL(5,   compat_sys_open)
@@ -211,7 +211,7 @@ __SYSCALL(186, compat_sys_sigaltstack_wrapper)
 __SYSCALL(187, compat_sys_sendfile)
 __SYSCALL(188, sys_ni_syscall)			/* 188 reserved */
 __SYSCALL(189, sys_ni_syscall)			/* 189 reserved */
-__SYSCALL(190, compat_sys_vfork)
+__SYSCALL(190, sys_vfork)
 __SYSCALL(191, compat_sys_getrlimit)		/* SuS compliant getrlimit */
 __SYSCALL(192, sys_mmap_pgoff)
 __SYSCALL(193, compat_sys_truncate64_wrapper)