Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 66 insertions, 0 deletions

diff --git a/arch/powerpc/lib/vmx-helper.c b/arch/powerpc/lib/vmx-helper.c
new file mode 100644
index 000000000..62e6c3045
--- /dev/null
+++ b/arch/powerpc/lib/vmx-helper.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * 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>
+#include <asm/asm-prototypes.h>
+
+int enter_vmx_usercopy(void)
+{
+	if (in_interrupt())
+		return 0;
+
+	preempt_disable();
+	/*
+	 * 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)
+{
+	disable_kernel_altivec();
+	pagefault_enable();
+	preempt_enable();
+	return 0;
+}
+
+int enter_vmx_ops(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_ops(void *dest)
+{
+	disable_kernel_altivec();
+	preempt_enable();
+	return dest;
+}