Root/arch/tile/lib/usercopy_32.S

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 * strnlen_user_asm takes the pointer in r0, and the length bound in r1.
24 * It returns the length, including the terminating NUL, or zero on exception.
25 * If length is greater than the bound, returns one plus the bound.
26 */
27STD_ENTRY(strnlen_user_asm)
28    { bz r1, 2f; addi r3, r0, -1 } /* bias down to include NUL */
291: { lb_u r4, r0; addi r1, r1, -1 }
30    bz r4, 2f
31    { bnzt r1, 1b; addi r0, r0, 1 }
322: { sub r0, r0, r3; jrp lr }
33    STD_ENDPROC(strnlen_user_asm)
34    .pushsection .fixup,"ax"
35strnlen_user_fault:
36    { move r0, zero; jrp lr }
37    ENDPROC(strnlen_user_fault)
38    .section __ex_table,"a"
39    .word 1b, strnlen_user_fault
40    .popsection
41
42/*
43 * strncpy_from_user_asm takes the kernel target pointer in r0,
44 * the userspace source pointer in r1, and the length bound (including
45 * the trailing NUL) in r2. On success, it returns the string length
46 * (not including the trailing NUL), or -EFAULT on failure.
47 */
48STD_ENTRY(strncpy_from_user_asm)
49    { bz r2, 2f; move r3, r0 }
501: { lb_u r4, r1; addi r1, r1, 1; addi r2, r2, -1 }
51    { sb r0, r4; addi r0, r0, 1 }
52    bz r2, 2f
53    bnzt r4, 1b
54    addi r0, r0, -1 /* don't count the trailing NUL */
552: { sub r0, r0, r3; jrp lr }
56    STD_ENDPROC(strncpy_from_user_asm)
57    .pushsection .fixup,"ax"
58strncpy_from_user_fault:
59    { movei r0, -EFAULT; jrp lr }
60    ENDPROC(strncpy_from_user_fault)
61    .section __ex_table,"a"
62    .word 1b, strncpy_from_user_fault
63    .popsection
64
65/*
66 * clear_user_asm takes the user target address in r0 and the
67 * number of bytes to zero in r1.
68 * It returns the number of uncopiable bytes (hopefully zero) in r0.
69 * Note that we don't use a separate .fixup section here since we fall
70 * through into the "fixup" code as the last straight-line bundle anyway.
71 */
72STD_ENTRY(clear_user_asm)
73    { bz r1, 2f; or r2, r0, r1 }
74    andi r2, r2, 3
75    bzt r2, .Lclear_aligned_user_asm
761: { sb r0, zero; addi r0, r0, 1; addi r1, r1, -1 }
77    bnzt r1, 1b
782: { move r0, r1; jrp lr }
79    .pushsection __ex_table,"a"
80    .word 1b, 2b
81    .popsection
82
83.Lclear_aligned_user_asm:
841: { sw r0, zero; addi r0, r0, 4; addi r1, r1, -4 }
85    bnzt r1, 1b
862: { move r0, r1; jrp lr }
87    STD_ENDPROC(clear_user_asm)
88    .pushsection __ex_table,"a"
89    .word 1b, 2b
90    .popsection
91
92/*
93 * flush_user_asm takes the user target address in r0 and the
94 * number of bytes to flush in r1.
95 * It returns the number of unflushable bytes (hopefully zero) in r0.
96 */
97STD_ENTRY(flush_user_asm)
98    bz r1, 2f
99    { movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
100    { sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
101    { and r0, r0, r2; and r1, r1, r2 }
102    { sub r1, r1, r0 }
1031: { flush r0; addi r1, r1, -CHIP_FLUSH_STRIDE() }
104    { addi r0, r0, CHIP_FLUSH_STRIDE(); bnzt r1, 1b }
1052: { move r0, r1; jrp lr }
106    STD_ENDPROC(flush_user_asm)
107    .pushsection __ex_table,"a"
108    .word 1b, 2b
109    .popsection
110
111/*
112 * inv_user_asm takes the user target address in r0 and the
113 * number of bytes to invalidate in r1.
114 * It returns the number of not inv'able bytes (hopefully zero) in r0.
115 */
116STD_ENTRY(inv_user_asm)
117    bz r1, 2f
118    { movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
119    { sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
120    { and r0, r0, r2; and r1, r1, r2 }
121    { sub r1, r1, r0 }
1221: { inv r0; addi r1, r1, -CHIP_INV_STRIDE() }
123    { addi r0, r0, CHIP_INV_STRIDE(); bnzt r1, 1b }
1242: { move r0, r1; jrp lr }
125    STD_ENDPROC(inv_user_asm)
126    .pushsection __ex_table,"a"
127    .word 1b, 2b
128    .popsection
129
130/*
131 * finv_user_asm takes the user target address in r0 and the
132 * number of bytes to flush-invalidate in r1.
133 * It returns the number of not finv'able bytes (hopefully zero) in r0.
134 */
135STD_ENTRY(finv_user_asm)
136    bz r1, 2f
137    { movei r2, L2_CACHE_BYTES; add r1, r0, r1 }
138    { sub r2, zero, r2; addi r1, r1, L2_CACHE_BYTES-1 }
139    { and r0, r0, r2; and r1, r1, r2 }
140    { sub r1, r1, r0 }
1411: { finv r0; addi r1, r1, -CHIP_FINV_STRIDE() }
142    { addi r0, r0, CHIP_FINV_STRIDE(); bnzt r1, 1b }
1432: { move r0, r1; jrp lr }
144    STD_ENDPROC(finv_user_asm)
145    .pushsection __ex_table,"a"
146    .word 1b, 2b
147    .popsection
148

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