xref: /linux/arch/hexagon/mm/copy_from_user.S (revision 24168c5e6dfbdd5b414f048f47f75d64533296ca)
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * User memory copy functions for kernel
4 *
5 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
6 */
7
8/*
9 * The right way to do this involves valignb
10 * The easy way to do this is only speed up src/dest similar alignment.
11 */
12
13/*
14 * Copy to/from user are the same, except that for packets with a load and
15 * a store, I don't know how to tell which kind of exception we got.
16 * Therefore, we duplicate the function, and handle faulting addresses
17 * differently for each function
18 */
19
20/*
21 * copy from user: loads can fault
22 */
23#define src_sav r13
24#define dst_sav r12
25#define src_dst_sav r13:12
26#define d_dbuf r15:14
27#define w_dbuf r15
28
29#define dst r0
30#define src r1
31#define bytes r2
32#define loopcount r5
33
34#define FUNCNAME raw_copy_from_user
35#include "copy_user_template.S"
36
37	/* LOAD FAULTS from COPY_FROM_USER */
38
39	/* Alignment loop.  r2 has been updated. Return it. */
40	.falign
411009:
422009:
434009:
44	{
45		r0 = r2
46		jumpr r31
47	}
48	/* Normal copy loops. Do epilog. Use src-src_sav to compute distance */
49	/* X - (A - B) == X + B - A */
50	.falign
518089:
52	{
53		memd(dst) = d_dbuf
54		r2 += sub(src_sav,src)
55	}
56	{
57		r0 = r2
58		jumpr r31
59	}
60	.falign
614089:
62	{
63		memw(dst) = w_dbuf
64		r2 += sub(src_sav,src)
65	}
66	{
67		r0 = r2
68		jumpr r31
69	}
70	.falign
712089:
72	{
73		memh(dst) = w_dbuf
74		r2 += sub(src_sav,src)
75	}
76	{
77		r0 = r2
78		jumpr r31
79	}
80	.falign
811089:
82	{
83		memb(dst) = w_dbuf
84		r2 += sub(src_sav,src)
85	}
86	{
87		r0 = r2
88		jumpr r31
89	}
90
91	/* COPY FROM USER: only loads can fail */
92
93	.section __ex_table,"a"
94	.long 1000b,1009b
95	.long 2000b,2009b
96	.long 4000b,4009b
97	.long 8080b,8089b
98	.long 4080b,4089b
99	.long 2080b,2089b
100	.long 1080b,1089b
101	.previous
102