config GENERIC_SIGALTSTACK
        bool
 
+config GENERIC_COMPAT_RT_SIGPROCMASK
+       bool
+
 #
 # ABI hall of shame
 #
 
 asmlinkage long compat_sys_adjtimex(struct compat_timex __user *utp);
 
 extern int compat_printk(const char *fmt, ...);
-extern void sigset_from_compat(sigset_t *set, compat_sigset_t *compat);
+extern void sigset_from_compat(sigset_t *set, const compat_sigset_t *compat);
+extern void sigset_to_compat(compat_sigset_t *compat, const sigset_t *set);
 
 asmlinkage long compat_sys_migrate_pages(compat_pid_t pid,
                compat_ulong_t maxnode, const compat_ulong_t __user *old_nodes,
                struct compat_timespec __user *uts, compat_size_t sigsetsize);
 asmlinkage long compat_sys_rt_sigsuspend(compat_sigset_t __user *unewset,
                                         compat_size_t sigsetsize);
+#ifdef CONFIG_GENERIC_COMPAT_RT_SIGPROCMASK
+asmlinkage long compat_sys_rt_sigprocmask(int how, compat_sigset_t __user *set,
+                                         compat_sigset_t __user *oset,
+                                         compat_size_t sigsetsize);
+#endif
 asmlinkage long compat_sys_sysinfo(struct compat_sysinfo __user *info);
 asmlinkage long compat_sys_ioctl(unsigned int fd, unsigned int cmd,
                                 unsigned long arg);
 
 }
 
 void
-sigset_from_compat (sigset_t *set, compat_sigset_t *compat)
+sigset_from_compat(sigset_t *set, const compat_sigset_t *compat)
 {
        switch (_NSIG_WORDS) {
        case 4: set->sig[3] = compat->sig[6] | (((long)compat->sig[7]) << 32 );
 }
 EXPORT_SYMBOL_GPL(sigset_from_compat);
 
+void
+sigset_to_compat(compat_sigset_t *compat, const sigset_t *set)
+{
+       switch (_NSIG_WORDS) {
+       case 4: compat->sig[7] = (set->sig[3] >> 32); compat->sig[6] = set->sig[3];
+       case 3: compat->sig[5] = (set->sig[2] >> 32); compat->sig[4] = set->sig[2];
+       case 2: compat->sig[3] = (set->sig[1] >> 32); compat->sig[2] = set->sig[1];
+       case 1: compat->sig[1] = (set->sig[0] >> 32); compat->sig[0] = set->sig[0];
+       }
+}
+
 asmlinkage long
 compat_sys_rt_sigtimedwait (compat_sigset_t __user *uthese,
                struct compat_siginfo __user *uinfo,
 
        return 0;
 }
 
+#ifdef CONFIG_COMPAT
+#ifdef CONFIG_GENERIC_COMPAT_RT_SIGPROCMASK
+COMPAT_SYSCALL_DEFINE4(rt_sigprocmask, int, how, compat_sigset_t __user *, nset,
+               compat_sigset_t __user *, oset, compat_size_t, sigsetsize)
+{
+#ifdef __BIG_ENDIAN
+       sigset_t old_set = current->blocked;
+
+       /* XXX: Don't preclude handling different sized sigset_t's.  */
+       if (sigsetsize != sizeof(sigset_t))
+               return -EINVAL;
+
+       if (nset) {
+               compat_sigset_t new32;
+               sigset_t new_set;
+               int error;
+               if (copy_from_user(&new32, nset, sizeof(compat_sigset_t)))
+                       return -EFAULT;
+
+               sigset_from_compat(&new_set, &new32);
+               sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
+
+               error = sigprocmask(how, &new_set, NULL);
+               if (error)
+                       return error;
+       }
+       if (oset) {
+               compat_sigset_t old32;
+               sigset_to_compat(&old32, &old_set);
+               if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
+                       return -EFAULT;
+       }
+       return 0;
+#else
+       return sys_rt_sigprocmask(how, (sigset_t __user *)nset,
+                                 (sigset_t __user *)oset, sigsetsize);
+#endif
+}
+#endif
+#endif
+
 long do_sigpending(void __user *set, unsigned long sigsetsize)
 {
        long error = -EINVAL;