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, 6 insertions, 0 deletions

diff --git a/arch/sparc64/kernel/signal32.c b/arch/sparc64/kernel/signal32.c
index 91f8d0826db..9415d2c918c 100644
--- a/arch/sparc64/kernel/signal32.c
+++ b/arch/sparc64/kernel/signal32.c
@@ -268,6 +268,9 @@ void do_sigreturn32(struct pt_regs *regs)
         regs->tstate &= ~(TSTATE_ICC|TSTATE_XCC);
         regs->tstate |= psr_to_tstate_icc(psr);
 
+        /* Prevent syscall restart.  */
+        pt_regs_clear_trap_type(regs);
+
         err |= __get_user(fpu_save, &sf->fpu_save);
         if (fpu_save)
                 err |= restore_fpu_state32(regs, &sf->fpu_state);
@@ -351,6 +354,9 @@ asmlinkage void do_rt_sigreturn32(struct pt_regs *regs)
         regs->tstate &= ~(TSTATE_ICC|TSTATE_XCC);
         regs->tstate |= psr_to_tstate_icc(psr);
 
+        /* Prevent syscall restart.  */
+        pt_regs_clear_trap_type(regs);
+
         err |= __get_user(fpu_save, &sf->fpu_save);
         if (fpu_save)
                 err |= restore_fpu_state32(regs, &sf->fpu_state);