Commit | Line | Data |
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1a59d1b8 | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
17968fbb | 2 | /* |
17968fbb AB |
3 | * |
4 | * Copyright (C) IBM Corporation, 2012 | |
5 | * | |
6 | * Author: Anton Blanchard <anton@au.ibm.com> | |
7 | */ | |
8 | ||
9 | #include <asm/ppc_asm.h> | |
24bfa6a9 | 10 | #include <asm/linkage.h> |
cf8fb553 | 11 | #include <asm/asm-offsets.h> |
9445aa1a | 12 | #include <asm/export.h> |
cf8fb553 AB |
13 | |
14 | .section ".toc","aw" | |
15 | PPC64_CACHES: | |
16 | .tc ppc64_caches[TC],ppc64_caches | |
17 | .section ".text" | |
17968fbb AB |
18 | |
19 | /** | |
20 | * __clear_user: - Zero a block of memory in user space, with less checking. | |
21 | * @to: Destination address, in user space. | |
22 | * @n: Number of bytes to zero. | |
23 | * | |
24 | * Zero a block of memory in user space. Caller must check | |
25 | * the specified block with access_ok() before calling this function. | |
26 | * | |
27 | * Returns number of bytes that could not be cleared. | |
28 | * On success, this will be zero. | |
29 | */ | |
30 | ||
31 | .macro err1 | |
32 | 100: | |
24bfa6a9 | 33 | EX_TABLE(100b,.Ldo_err1) |
17968fbb AB |
34 | .endm |
35 | ||
36 | .macro err2 | |
37 | 200: | |
24bfa6a9 | 38 | EX_TABLE(200b,.Ldo_err2) |
17968fbb AB |
39 | .endm |
40 | ||
41 | .macro err3 | |
42 | 300: | |
24bfa6a9 | 43 | EX_TABLE(300b,.Ldo_err3) |
17968fbb AB |
44 | .endm |
45 | ||
46 | .Ldo_err1: | |
47 | mr r3,r8 | |
48 | ||
49 | .Ldo_err2: | |
50 | mtctr r4 | |
51 | 1: | |
52 | err3; stb r0,0(r3) | |
53 | addi r3,r3,1 | |
54 | addi r4,r4,-1 | |
55 | bdnz 1b | |
56 | ||
57 | .Ldo_err3: | |
58 | mr r3,r4 | |
59 | blr | |
60 | ||
2ac7b016 | 61 | _GLOBAL_TOC(__clear_user) |
17968fbb AB |
62 | cmpdi r4,32 |
63 | neg r6,r3 | |
64 | li r0,0 | |
65 | blt .Lshort_clear | |
66 | mr r8,r3 | |
67 | mtocrf 0x01,r6 | |
68 | clrldi r6,r6,(64-3) | |
69 | ||
70 | /* Get the destination 8 byte aligned */ | |
71 | bf cr7*4+3,1f | |
72 | err1; stb r0,0(r3) | |
73 | addi r3,r3,1 | |
74 | ||
75 | 1: bf cr7*4+2,2f | |
76 | err1; sth r0,0(r3) | |
77 | addi r3,r3,2 | |
78 | ||
79 | 2: bf cr7*4+1,3f | |
80 | err1; stw r0,0(r3) | |
81 | addi r3,r3,4 | |
82 | ||
83 | 3: sub r4,r4,r6 | |
cf8fb553 | 84 | |
17968fbb | 85 | cmpdi r4,32 |
cf8fb553 | 86 | cmpdi cr1,r4,512 |
17968fbb | 87 | blt .Lshort_clear |
cf8fb553 AB |
88 | bgt cr1,.Llong_clear |
89 | ||
90 | .Lmedium_clear: | |
91 | srdi r6,r4,5 | |
17968fbb AB |
92 | mtctr r6 |
93 | ||
94 | /* Do 32 byte chunks */ | |
95 | 4: | |
96 | err2; std r0,0(r3) | |
97 | err2; std r0,8(r3) | |
98 | err2; std r0,16(r3) | |
99 | err2; std r0,24(r3) | |
100 | addi r3,r3,32 | |
101 | addi r4,r4,-32 | |
102 | bdnz 4b | |
103 | ||
104 | .Lshort_clear: | |
105 | /* up to 31 bytes to go */ | |
106 | cmpdi r4,16 | |
107 | blt 6f | |
108 | err2; std r0,0(r3) | |
109 | err2; std r0,8(r3) | |
110 | addi r3,r3,16 | |
111 | addi r4,r4,-16 | |
112 | ||
113 | /* Up to 15 bytes to go */ | |
114 | 6: mr r8,r3 | |
115 | clrldi r4,r4,(64-4) | |
116 | mtocrf 0x01,r4 | |
117 | bf cr7*4+0,7f | |
118 | err1; std r0,0(r3) | |
119 | addi r3,r3,8 | |
120 | ||
121 | 7: bf cr7*4+1,8f | |
122 | err1; stw r0,0(r3) | |
123 | addi r3,r3,4 | |
124 | ||
125 | 8: bf cr7*4+2,9f | |
126 | err1; sth r0,0(r3) | |
127 | addi r3,r3,2 | |
128 | ||
129 | 9: bf cr7*4+3,10f | |
130 | err1; stb r0,0(r3) | |
131 | ||
132 | 10: li r3,0 | |
133 | blr | |
cf8fb553 AB |
134 | |
135 | .Llong_clear: | |
136 | ld r5,PPC64_CACHES@toc(r2) | |
137 | ||
138 | bf cr7*4+0,11f | |
139 | err2; std r0,0(r3) | |
140 | addi r3,r3,8 | |
141 | addi r4,r4,-8 | |
142 | ||
bd067f83 BH |
143 | /* Destination is 16 byte aligned, need to get it cache block aligned */ |
144 | 11: lwz r7,DCACHEL1LOGBLOCKSIZE(r5) | |
145 | lwz r9,DCACHEL1BLOCKSIZE(r5) | |
cf8fb553 AB |
146 | |
147 | /* | |
148 | * With worst case alignment the long clear loop takes a minimum | |
149 | * of 1 byte less than 2 cachelines. | |
150 | */ | |
151 | sldi r10,r9,2 | |
152 | cmpd r4,r10 | |
153 | blt .Lmedium_clear | |
154 | ||
155 | neg r6,r3 | |
156 | addi r10,r9,-1 | |
157 | and. r5,r6,r10 | |
158 | beq 13f | |
159 | ||
160 | srdi r6,r5,4 | |
161 | mtctr r6 | |
162 | mr r8,r3 | |
163 | 12: | |
164 | err1; std r0,0(r3) | |
165 | err1; std r0,8(r3) | |
166 | addi r3,r3,16 | |
167 | bdnz 12b | |
168 | ||
169 | sub r4,r4,r5 | |
170 | ||
171 | 13: srd r6,r4,r7 | |
172 | mtctr r6 | |
173 | mr r8,r3 | |
174 | 14: | |
8a583c0a | 175 | err1; dcbz 0,r3 |
cf8fb553 AB |
176 | add r3,r3,r9 |
177 | bdnz 14b | |
178 | ||
179 | and r4,r4,r10 | |
180 | ||
181 | cmpdi r4,32 | |
182 | blt .Lshort_clear | |
183 | b .Lmedium_clear | |
9445aa1a | 184 | EXPORT_SYMBOL(__clear_user) |