sparc: Fix fork/clone/vfork system call restart.

We clobber %i1 as well as %i0 for these system calls,
because they give two return values.

Therefore, on error, we have to restore %i1 properly
or else the restart explodes since it uses the wrong
arguments.

This fixes glibc's nptl/tst-eintr1.c testcase.

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

1 files changed, 16 insertions, 4 deletions

diff --git a/arch/sparc/kernel/process.c b/arch/sparc/kernel/process.c
index e7f3519..36431f3 100644
--- a/arch/sparc/kernel/process.c
+++ b/arch/sparc/kernel/process.c
@@ -419,14 +419,26 @@ asmlinkage int sparc_do_fork(unsigned long clone_flags,
                              unsigned long stack_size)
 {
 	unsigned long parent_tid_ptr, child_tid_ptr;
+	unsigned long orig_i1 = regs->u_regs[UREG_I1];
+	long ret;
 
 	parent_tid_ptr = regs->u_regs[UREG_I2];
 	child_tid_ptr = regs->u_regs[UREG_I4];
 
-	return do_fork(clone_flags, stack_start,
-		       regs, stack_size,
-		       (int __user *) parent_tid_ptr,
-		       (int __user *) child_tid_ptr);
+	ret = do_fork(clone_flags, stack_start,
+		      regs, stack_size,
+		      (int __user *) parent_tid_ptr,
+		      (int __user *) child_tid_ptr);
+
+	/* If we get an error and potentially restart the system
+	 * call, we're screwed because copy_thread() clobbered
+	 * the parent's %o1.  So detect that case and restore it
+	 * here.
+	 */
+	if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
+		regs->u_regs[UREG_I1] = orig_i1;
+
+	return ret;
 }
 
 /* Copy a Sparc thread.  The fork() return value conventions