1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * User memory copying routines for the Hexagon Kernel
4 *
5 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
6 */
7
8/* The right way to do this involves valignb
9 * The easy way to do this is only speed up src/dest similar alignment.
10 */
11
12/*
13 * Copy to/from user are the same, except that for packets with a load and
14 * a store, I don't know how to tell which kind of exception we got.
15 * Therefore, we duplicate the function, and handle faulting addresses
16 * differently for each function
17 */
18
19/*
20 * copy to user: stores can fault
21 */
22#define src_sav r13
23#define dst_sav r12
24#define src_dst_sav r13:12
25#define d_dbuf r15:14
26#define w_dbuf r15
27
28#define dst r0
29#define src r1
30#define bytes r2
31#define loopcount r5
32
33#define FUNCNAME raw_copy_to_user
34#include "copy_user_template.S"
35
36 /* STORE FAULTS from COPY_TO_USER */
37 .falign
381109:
392109:
404109:
41 /* Alignment loop. r2 has been updated. Return it. */
42 {
43 r0 = r2
44 jumpr r31
45 }
46 /* Normal copy loops. Use dst-dst_sav to compute distance */
47 /* dst holds best write, no need to unwind any loops */
48 /* X - (A - B) == X + B - A */
49 .falign
508189:
518199:
524189:
534199:
542189:
552199:
561189:
571199:
58 {
59 r2 += sub(dst_sav,dst)
60 }
61 {
62 r0 = r2
63 jumpr r31
64 }
65
66 /* COPY TO USER: only stores can fail */
67 .section __ex_table,"a"
68 .long 1100b,1109b
69 .long 2100b,2109b
70 .long 4100b,4109b
71 .long 8180b,8189b
72 .long 8190b,8199b
73 .long 4180b,4189b
74 .long 4190b,4199b
75 .long 2180b,2189b
76 .long 2190b,2199b
77 .long 1180b,1189b
78 .long 1190b,1199b
79 .previous
80

source code of linux/arch/hexagon/mm/copy_to_user.S