1 files changed, 23 insertions, 0 deletions

diff --git a/arch/blackfin/kernel/sys_bfin.c b/arch/blackfin/kernel/sys_bfin.c
index 2e7f8e10bf87..bdc1e2f0da32 100644
--- a/arch/blackfin/kernel/sys_bfin.c
+++ b/arch/blackfin/kernel/sys_bfin.c
@@ -47,3 +47,26 @@ unsigned long get_fb_unmapped_area(struct file *filp, unsigned long orig_addr,
 }
 EXPORT_SYMBOL(get_fb_unmapped_area);
 #endif
+
+/* Needed for legacy userspace atomic emulation */
+static DEFINE_SPINLOCK(bfin_spinlock_lock);
+
+#ifdef CONFIG_SYS_BFIN_SPINLOCK_L1
+__attribute__((l1_text))
+#endif
+asmlinkage int sys_bfin_spinlock(int *p)
+{
+        int ret, tmp = 0;
+
+        spin_lock(&bfin_spinlock_lock); /* This would also hold kernel preemption. */
+        ret = get_user(tmp, p);
+        if (likely(ret == 0)) {
+                if (unlikely(tmp))
+                        ret = 1;
+                else
+                        put_user(1, p);
+        }
+        spin_unlock(&bfin_spinlock_lock);
+
+        return ret;
+}