Hexagon: Add user access functions
Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/hexagon/mm/copy_to_user.S b/arch/hexagon/mm/copy_to_user.S
new file mode 100644
index 0000000..cb9740e
--- /dev/null
+++ b/arch/hexagon/mm/copy_to_user.S
@@ -0,0 +1,92 @@
+/*
+ * User memory copying routines for the Hexagon Kernel
+ *
+ * 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.
+ */
+
+/* The right way to do this involves valignb
+ * The easy way to do this is only speed up src/dest similar alignment.
+ */
+
+/*
+ * Copy to/from user are the same, except that for packets with a load and
+ * a store, I don't know how to tell which kind of exception we got.
+ * Therefore, we duplicate the function, and handle faulting addresses
+ * differently for each function
+ */
+
+/*
+ * copy to user: stores can fault
+ */
+#define src_sav r13
+#define dst_sav r12
+#define src_dst_sav r13:12
+#define d_dbuf r15:14
+#define w_dbuf r15
+
+#define dst r0
+#define src r1
+#define bytes r2
+#define loopcount r5
+
+#define FUNCNAME __copy_to_user_hexagon
+#include "copy_user_template.S"
+
+ /* STORE FAULTS from COPY_TO_USER */
+ .falign
+1109:
+2109:
+4109:
+ /* Alignment loop. r2 has been updated. Return it. */
+ {
+ r0 = r2
+ jumpr r31
+ }
+ /* Normal copy loops. Use dst-dst_sav to compute distance */
+ /* dst holds best write, no need to unwind any loops */
+ /* X - (A - B) == X + B - A */
+ .falign
+8189:
+8199:
+4189:
+4199:
+2189:
+2199:
+1189:
+1199:
+ {
+ r2 += sub(dst_sav,dst)
+ }
+ {
+ r0 = r2
+ jumpr r31
+ }
+
+ /* COPY TO USER: only stores can fail */
+ .section __ex_table,"a"
+ .long 1100b,1109b
+ .long 2100b,2109b
+ .long 4100b,4109b
+ .long 8180b,8189b
+ .long 8190b,8199b
+ .long 4180b,4189b
+ .long 4190b,4199b
+ .long 2180b,2189b
+ .long 2190b,2199b
+ .long 1180b,1189b
+ .long 1190b,1199b
+ .previous