1 files changed, 74 insertions, 0 deletions

diff --git a/arch/powerpc/lib/vmx-helper.c b/arch/powerpc/lib/vmx-helper.c
new file mode 100644
index 000000000000..3cf529ceec5b
--- /dev/null
+++ b/arch/powerpc/lib/vmx-helper.c
@@ -0,0 +1,74 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2011
+ *
+ * Authors: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
+ *          Anton Blanchard <anton@au.ibm.com>
+ */
+#include <linux/uaccess.h>
+#include <linux/hardirq.h>
+#include <asm/switch_to.h>
+
+int enter_vmx_usercopy(void)
+{
+        if (in_interrupt())
+                return 0;
+
+        /* This acts as preempt_disable() as well and will make
+         * enable_kernel_altivec(). We need to disable page faults
+         * as they can call schedule and thus make us lose the VMX
+         * context. So on page faults, we just fail which will cause
+         * a fallback to the normal non-vmx copy.
+         */
+        pagefault_disable();
+
+        enable_kernel_altivec();
+
+        return 1;
+}
+
+/*
+ * This function must return 0 because we tail call optimise when calling
+ * from __copy_tofrom_user_power7 which returns 0 on success.
+ */
+int exit_vmx_usercopy(void)
+{
+        pagefault_enable();
+        return 0;
+}
+
+int enter_vmx_copy(void)
+{
+        if (in_interrupt())
+                return 0;
+
+        preempt_disable();
+
+        enable_kernel_altivec();
+
+        return 1;
+}
+
+/*
+ * All calls to this function will be optimised into tail calls. We are
+ * passed a pointer to the destination which we return as required by a
+ * memcpy implementation.
+ */
+void *exit_vmx_copy(void *dest)
+{
+        preempt_enable();
+        return dest;
+}