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17968fbb AB |
1 | /* |
2 | * This program is free software; you can redistribute it and/or modify | |
3 | * it under the terms of the GNU General Public License as published by | |
4 | * the Free Software Foundation; either version 2 of the License, or | |
5 | * (at your option) any later version. | |
6 | * | |
7 | * This program is distributed in the hope that it will be useful, | |
8 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
10 | * GNU General Public License for more details. | |
11 | * | |
12 | * You should have received a copy of the GNU General Public License | |
13 | * along with this program; if not, write to the Free Software | |
14 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
15 | * | |
16 | * Copyright (C) IBM Corporation, 2012 | |
17 | * | |
18 | * Author: Anton Blanchard <anton@au.ibm.com> | |
19 | */ | |
20 | ||
21 | #include <asm/ppc_asm.h> | |
cf8fb553 | 22 | #include <asm/asm-offsets.h> |
9445aa1a | 23 | #include <asm/export.h> |
cf8fb553 AB |
24 | |
25 | .section ".toc","aw" | |
26 | PPC64_CACHES: | |
27 | .tc ppc64_caches[TC],ppc64_caches | |
28 | .section ".text" | |
17968fbb AB |
29 | |
30 | /** | |
31 | * __clear_user: - Zero a block of memory in user space, with less checking. | |
32 | * @to: Destination address, in user space. | |
33 | * @n: Number of bytes to zero. | |
34 | * | |
35 | * Zero a block of memory in user space. Caller must check | |
36 | * the specified block with access_ok() before calling this function. | |
37 | * | |
38 | * Returns number of bytes that could not be cleared. | |
39 | * On success, this will be zero. | |
40 | */ | |
41 | ||
42 | .macro err1 | |
43 | 100: | |
44 | .section __ex_table,"a" | |
45 | .align 3 | |
46 | .llong 100b,.Ldo_err1 | |
47 | .previous | |
48 | .endm | |
49 | ||
50 | .macro err2 | |
51 | 200: | |
52 | .section __ex_table,"a" | |
53 | .align 3 | |
54 | .llong 200b,.Ldo_err2 | |
55 | .previous | |
56 | .endm | |
57 | ||
58 | .macro err3 | |
59 | 300: | |
60 | .section __ex_table,"a" | |
61 | .align 3 | |
62 | .llong 300b,.Ldo_err3 | |
63 | .previous | |
64 | .endm | |
65 | ||
66 | .Ldo_err1: | |
67 | mr r3,r8 | |
68 | ||
69 | .Ldo_err2: | |
70 | mtctr r4 | |
71 | 1: | |
72 | err3; stb r0,0(r3) | |
73 | addi r3,r3,1 | |
74 | addi r4,r4,-1 | |
75 | bdnz 1b | |
76 | ||
77 | .Ldo_err3: | |
78 | mr r3,r4 | |
79 | blr | |
80 | ||
2ac7b016 | 81 | _GLOBAL_TOC(__clear_user) |
17968fbb AB |
82 | cmpdi r4,32 |
83 | neg r6,r3 | |
84 | li r0,0 | |
85 | blt .Lshort_clear | |
86 | mr r8,r3 | |
87 | mtocrf 0x01,r6 | |
88 | clrldi r6,r6,(64-3) | |
89 | ||
90 | /* Get the destination 8 byte aligned */ | |
91 | bf cr7*4+3,1f | |
92 | err1; stb r0,0(r3) | |
93 | addi r3,r3,1 | |
94 | ||
95 | 1: bf cr7*4+2,2f | |
96 | err1; sth r0,0(r3) | |
97 | addi r3,r3,2 | |
98 | ||
99 | 2: bf cr7*4+1,3f | |
100 | err1; stw r0,0(r3) | |
101 | addi r3,r3,4 | |
102 | ||
103 | 3: sub r4,r4,r6 | |
cf8fb553 | 104 | |
17968fbb | 105 | cmpdi r4,32 |
cf8fb553 | 106 | cmpdi cr1,r4,512 |
17968fbb | 107 | blt .Lshort_clear |
cf8fb553 AB |
108 | bgt cr1,.Llong_clear |
109 | ||
110 | .Lmedium_clear: | |
111 | srdi r6,r4,5 | |
17968fbb AB |
112 | mtctr r6 |
113 | ||
114 | /* Do 32 byte chunks */ | |
115 | 4: | |
116 | err2; std r0,0(r3) | |
117 | err2; std r0,8(r3) | |
118 | err2; std r0,16(r3) | |
119 | err2; std r0,24(r3) | |
120 | addi r3,r3,32 | |
121 | addi r4,r4,-32 | |
122 | bdnz 4b | |
123 | ||
124 | .Lshort_clear: | |
125 | /* up to 31 bytes to go */ | |
126 | cmpdi r4,16 | |
127 | blt 6f | |
128 | err2; std r0,0(r3) | |
129 | err2; std r0,8(r3) | |
130 | addi r3,r3,16 | |
131 | addi r4,r4,-16 | |
132 | ||
133 | /* Up to 15 bytes to go */ | |
134 | 6: mr r8,r3 | |
135 | clrldi r4,r4,(64-4) | |
136 | mtocrf 0x01,r4 | |
137 | bf cr7*4+0,7f | |
138 | err1; std r0,0(r3) | |
139 | addi r3,r3,8 | |
140 | ||
141 | 7: bf cr7*4+1,8f | |
142 | err1; stw r0,0(r3) | |
143 | addi r3,r3,4 | |
144 | ||
145 | 8: bf cr7*4+2,9f | |
146 | err1; sth r0,0(r3) | |
147 | addi r3,r3,2 | |
148 | ||
149 | 9: bf cr7*4+3,10f | |
150 | err1; stb r0,0(r3) | |
151 | ||
152 | 10: li r3,0 | |
153 | blr | |
cf8fb553 AB |
154 | |
155 | .Llong_clear: | |
156 | ld r5,PPC64_CACHES@toc(r2) | |
157 | ||
158 | bf cr7*4+0,11f | |
159 | err2; std r0,0(r3) | |
160 | addi r3,r3,8 | |
161 | addi r4,r4,-8 | |
162 | ||
163 | /* Destination is 16 byte aligned, need to get it cacheline aligned */ | |
164 | 11: lwz r7,DCACHEL1LOGLINESIZE(r5) | |
165 | lwz r9,DCACHEL1LINESIZE(r5) | |
166 | ||
167 | /* | |
168 | * With worst case alignment the long clear loop takes a minimum | |
169 | * of 1 byte less than 2 cachelines. | |
170 | */ | |
171 | sldi r10,r9,2 | |
172 | cmpd r4,r10 | |
173 | blt .Lmedium_clear | |
174 | ||
175 | neg r6,r3 | |
176 | addi r10,r9,-1 | |
177 | and. r5,r6,r10 | |
178 | beq 13f | |
179 | ||
180 | srdi r6,r5,4 | |
181 | mtctr r6 | |
182 | mr r8,r3 | |
183 | 12: | |
184 | err1; std r0,0(r3) | |
185 | err1; std r0,8(r3) | |
186 | addi r3,r3,16 | |
187 | bdnz 12b | |
188 | ||
189 | sub r4,r4,r5 | |
190 | ||
191 | 13: srd r6,r4,r7 | |
192 | mtctr r6 | |
193 | mr r8,r3 | |
194 | 14: | |
195 | err1; dcbz r0,r3 | |
196 | add r3,r3,r9 | |
197 | bdnz 14b | |
198 | ||
199 | and r4,r4,r10 | |
200 | ||
201 | cmpdi r4,32 | |
202 | blt .Lshort_clear | |
203 | b .Lmedium_clear | |
9445aa1a | 204 | EXPORT_SYMBOL(__clear_user) |