From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 arch/sparc/lib/user_fixup.c | 71 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 arch/sparc/lib/user_fixup.c

(limited to 'arch/sparc/lib/user_fixup.c')

diff --git a/arch/sparc/lib/user_fixup.c b/arch/sparc/lib/user_fixup.c
new file mode 100644
index 000000000..ac96ae236
--- /dev/null
+++ b/arch/sparc/lib/user_fixup.c
@@ -0,0 +1,71 @@
+/* user_fixup.c: Fix up user copy faults.
+ *
+ * Copyright (C) 2004 David S. Miller <davem@redhat.com>
+ */
+
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+
+#include <asm/uaccess.h>
+
+/* Calculating the exact fault address when using
+ * block loads and stores can be very complicated.
+ *
+ * Instead of trying to be clever and handling all
+ * of the cases, just fix things up simply here.
+ */
+
+static unsigned long compute_size(unsigned long start, unsigned long size, unsigned long *offset)
+{
+	unsigned long fault_addr = current_thread_info()->fault_address;
+	unsigned long end = start + size;
+
+	if (fault_addr < start || fault_addr >= end) {
+		*offset = 0;
+	} else {
+		*offset = fault_addr - start;
+		size = end - fault_addr;
+	}
+	return size;
+}
+
+unsigned long copy_from_user_fixup(void *to, const void __user *from, unsigned long size)
+{
+	unsigned long offset;
+
+	size = compute_size((unsigned long) from, size, &offset);
+	if (likely(size))
+		memset(to + offset, 0, size);
+
+	return size;
+}
+EXPORT_SYMBOL(copy_from_user_fixup);
+
+unsigned long copy_to_user_fixup(void __user *to, const void *from, unsigned long size)
+{
+	unsigned long offset;
+
+	return compute_size((unsigned long) to, size, &offset);
+}
+EXPORT_SYMBOL(copy_to_user_fixup);
+
+unsigned long copy_in_user_fixup(void __user *to, void __user *from, unsigned long size)
+{
+	unsigned long fault_addr = current_thread_info()->fault_address;
+	unsigned long start = (unsigned long) to;
+	unsigned long end = start + size;
+
+	if (fault_addr >= start && fault_addr < end)
+		return end - fault_addr;
+
+	start = (unsigned long) from;
+	end = start + size;
+	if (fault_addr >= start && fault_addr < end)
+		return end - fault_addr;
+
+	return size;
+}
+EXPORT_SYMBOL(copy_in_user_fixup);
-- 
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