copy_to_user.S
/*
* User memory copying routines for the Hexagon Kernel
*
* Copyright (c) 2010-2011, The Linux Foundation. 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