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-rw-r--r--arch/hexagon/mm/uaccess.c59
1 files changed, 59 insertions, 0 deletions
diff --git a/arch/hexagon/mm/uaccess.c b/arch/hexagon/mm/uaccess.c
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+++ b/arch/hexagon/mm/uaccess.c
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+/*
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+/*
+ * Support for user memory access from kernel. This will
+ * probably be inlined for performance at some point, but
+ * for ease of debug, and to a lesser degree for code size,
+ * we implement here as subroutines.
+ */
+#include <linux/types.h>
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+
+/*
+ * For clear_user(), exploit previously defined copy_to_user function
+ * and the fact that we've got a handy zero page defined in kernel/head.S
+ *
+ * dczero here would be even faster.
+ */
+__kernel_size_t __clear_user_hexagon(void __user *dest, unsigned long count)
+{
+ long uncleared;
+
+ while (count > PAGE_SIZE) {
+ uncleared = __copy_to_user_hexagon(dest, &empty_zero_page,
+ PAGE_SIZE);
+ if (uncleared)
+ return count - (PAGE_SIZE - uncleared);
+ count -= PAGE_SIZE;
+ dest += PAGE_SIZE;
+ }
+ if (count)
+ count = __copy_to_user_hexagon(dest, &empty_zero_page, count);
+
+ return count;
+}
+
+unsigned long clear_user_hexagon(void __user *dest, unsigned long count)
+{
+ if (!access_ok(VERIFY_WRITE, dest, count))
+ return count;
+ else
+ return __clear_user_hexagon(dest, count);
+}