Blackfin: add support for restart_syscall()

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

arch/blackfin/kernel/signal.c

@@ -17,6 +17,7 @@
 #include <asm/cacheflush.h>
 #include <asm/ucontext.h>
 #include <asm/fixed_code.h>
+#include <asm/syscall.h>
 
 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 
@@ -50,6 +51,9 @@ rt_restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *p
 	unsigned long usp = 0;
 	int err = 0;
 
+	/* Always make any pending restarted system calls return -EINTR */
+	current_thread_info()->restart_block.fn = do_no_restart_syscall;
+
 #define RESTORE(x) err |= __get_user(regs->x, &sc->sc_##x)
 
 	/* restore passed registers */
@@ -237,6 +241,11 @@ handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
 		regs->r0 = regs->orig_r0;
 		regs->pc -= 2;
 		break;
+
+	case -ERESTART_RESTARTBLOCK:
+		regs->p0 = __NR_restart_syscall;
+		regs->pc -= 2;
+		break;
 	}
 }