sparc64: Fix syscall restart, for real...

The change I put into copy_thread() just papered over the real
problem.

When we are looking to see if we should do a syscall restart, when
deliverying a signal, we should only interpret the syscall return
value as an error if the carry condition code(s) are set.

Otherwise it's a success return.

Also, sigreturn paths should do a pt_regs_clear_trap_type().

It turns out that doing a syscall restart when returning from a fork()
does and should happen, from time to time.  Even if copy_thread()
returns success, copy_process() can still unwind and signal
-ERESTARTNOINTR in the parent.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 1 deletions

diff --git a/arch/sparc64/kernel/signal.c b/arch/sparc64/kernel/signal.c
index f2d88d8f7a42..45d6bf632daa 100644
--- a/arch/sparc64/kernel/signal.c
+++ b/arch/sparc64/kernel/signal.c
@@ -332,6 +332,9 @@ void do_rt_sigreturn(struct pt_regs *regs)
         regs->tpc = tpc;
         regs->tnpc = tnpc;
 
+        /* Prevent syscall restart.  */
+        pt_regs_clear_trap_type(regs);
+
         sigdelsetmask(&set, ~_BLOCKABLE);
         spin_lock_irq(&current->sighand->siglock);
         current->blocked = set;
@@ -515,7 +518,8 @@ static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
         siginfo_t info;
         int signr;
         
-        if (pt_regs_is_syscall(regs)) {
+        if (pt_regs_is_syscall(regs) &&
+            (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) {
                 pt_regs_clear_trap_type(regs);
                 cookie.restart_syscall = 1;
         } else