1/*
2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
3 *
4 *   This program is free software; you can redistribute it and/or
5 *   modify it under the terms of the GNU General Public License
6 *   as published by the Free Software Foundation, version 2.
7 *
8 *   This program is distributed in the hope that it will be useful, but
9 *   WITHOUT ANY WARRANTY; without even the implied warranty of
10 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
11 *   NON INFRINGEMENT.  See the GNU General Public License for
12 *   more details.
13 */
14
15#include <linux/linkage.h>
16#include <asm/errno.h>
17#include <asm/cache.h>
18#include <arch/chip.h>
19
20/* Access user memory, but use MMU to avoid propagating kernel exceptions. */
21
22/*
23 * clear_user_asm takes the user target address in r0 and the
24 * number of bytes to zero in r1.
25 * It returns the number of uncopiable bytes (hopefully zero) in r0.
26 * Note that we don't use a separate .fixup section here since we fall
27 * through into the "fixup" code as the last straight-line bundle anyway.
28 */
29STD_ENTRY(clear_user_asm)
30	{ bz r1, 2f; or r2, r0, r1 }
31	andi r2, r2, 3
32	bzt r2, .Lclear_aligned_user_asm
331:      { sb r0, zero; addi r0, r0, 1; addi r1, r1, -1 }
34	bnzt r1, 1b
352:      { move r0, r1; jrp lr }
36	.pushsection __ex_table,"a"
37	.align 4
38	.word 1b, 2b
39	.popsection
40
41.Lclear_aligned_user_asm:
421:      { sw r0, zero; addi r0, r0, 4; addi r1, r1, -4 }
43	bnzt r1, 1b
442:      { move r0, r1; jrp lr }
45	STD_ENDPROC(clear_user_asm)
46	.pushsection __ex_table,"a"
47	.align 4
48	.word 1b, 2b
49	.popsection
50
51/*
52 * flush_user_asm takes the user target address in r0 and the
53 * number of bytes to flush in r1.
54 * It returns the number of unflushable bytes (hopefully zero) in r0.
55 */
56STD_ENTRY(flush_user_asm)
57	bz r1, 2f
58	{ movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
59	{ sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
60	{ and r0, r0, r2; and r1, r1, r2 }
61	{ sub r1, r1, r0 }
621:      { flush r0; addi r1, r1, -CHIP_FLUSH_STRIDE() }
63	{ addi r0, r0, CHIP_FLUSH_STRIDE(); bnzt r1, 1b }
642:      { move r0, r1; jrp lr }
65	STD_ENDPROC(flush_user_asm)
66	.pushsection __ex_table,"a"
67	.align 4
68	.word 1b, 2b
69	.popsection
70
71/*
72 * finv_user_asm takes the user target address in r0 and the
73 * number of bytes to flush-invalidate in r1.
74 * It returns the number of not finv'able bytes (hopefully zero) in r0.
75 */
76STD_ENTRY(finv_user_asm)
77	bz r1, 2f
78	{ movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
79	{ sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
80	{ and r0, r0, r2; and r1, r1, r2 }
81	{ sub r1, r1, r0 }
821:      { finv r0; addi r1, r1, -CHIP_FINV_STRIDE() }
83	{ addi r0, r0, CHIP_FINV_STRIDE(); bnzt r1, 1b }
842:      { move r0, r1; jrp lr }
85	STD_ENDPROC(finv_user_asm)
86	.pushsection __ex_table,"a"
87	.align 4
88	.word 1b, 2b
89	.popsection
90