projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 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 | ||
| 39326182 | 9 | #include <linux/export.h> |
| 17968fbb | 10 | #include <asm/ppc_asm.h> |
| 24bfa6a9 | 11 | #include <asm/linkage.h> |
| cf8fb553 AB |
12 | #include <asm/asm-offsets.h> |
| 13 | ||
| 17968fbb | 14 | /** |
| 61e3acd8 | 15 | * __arch_clear_user: - Zero a block of memory in user space, with less checking. |
| 17968fbb AB |
16 | * @to: Destination address, in user space. |
| 17 | * @n: Number of bytes to zero. | |
| 18 | * | |
| 19 | * Zero a block of memory in user space. Caller must check | |
| 20 | * the specified block with access_ok() before calling this function. | |
| 21 | * | |
| 22 | * Returns number of bytes that could not be cleared. | |
| 23 | * On success, this will be zero. | |
| 24 | */ | |
| 25 | ||
| 26 | .macro err1 | |
| 27 | 100: | |
| 24bfa6a9 | 28 | EX_TABLE(100b,.Ldo_err1) |
| 17968fbb AB |
29 | .endm |
| 30 | ||
| 31 | .macro err2 | |
| 32 | 200: | |
| 24bfa6a9 | 33 | EX_TABLE(200b,.Ldo_err2) |
| 17968fbb AB |
34 | .endm |
| 35 | ||
| 36 | .macro err3 | |
| 37 | 300: | |
| 24bfa6a9 | 38 | EX_TABLE(300b,.Ldo_err3) |
| 17968fbb AB |
39 | .endm |
| 40 | ||
| 41 | .Ldo_err1: | |
| 42 | mr r3,r8 | |
| 43 | ||
| 44 | .Ldo_err2: | |
| 45 | mtctr r4 | |
| 46 | 1: | |
| 47 | err3; stb r0,0(r3) | |
| 48 | addi r3,r3,1 | |
| 49 | addi r4,r4,-1 | |
| 50 | bdnz 1b | |
| 51 | ||
| 52 | .Ldo_err3: | |
| 53 | mr r3,r4 | |
| 54 | blr | |
| 55 | ||
| 61e3acd8 | 56 | _GLOBAL_TOC(__arch_clear_user) |
| 17968fbb AB |
57 | cmpdi r4,32 |
| 58 | neg r6,r3 | |
| 59 | li r0,0 | |
| 60 | blt .Lshort_clear | |
| 61 | mr r8,r3 | |
| 62 | mtocrf 0x01,r6 | |
| 63 | clrldi r6,r6,(64-3) | |
| 64 | ||
| 65 | /* Get the destination 8 byte aligned */ | |
| 66 | bf cr7*4+3,1f | |
| 67 | err1; stb r0,0(r3) | |
| 68 | addi r3,r3,1 | |
| 69 | ||
| 70 | 1: bf cr7*4+2,2f | |
| 71 | err1; sth r0,0(r3) | |
| 72 | addi r3,r3,2 | |
| 73 | ||
| 74 | 2: bf cr7*4+1,3f | |
| 75 | err1; stw r0,0(r3) | |
| 76 | addi r3,r3,4 | |
| 77 | ||
| 78 | 3: sub r4,r4,r6 | |
| cf8fb553 | 79 | |
| 17968fbb | 80 | cmpdi r4,32 |
| cf8fb553 | 81 | cmpdi cr1,r4,512 |
| 17968fbb | 82 | blt .Lshort_clear |
| cf8fb553 AB |
83 | bgt cr1,.Llong_clear |
| 84 | ||
| 85 | .Lmedium_clear: | |
| 86 | srdi r6,r4,5 | |
| 17968fbb AB |
87 | mtctr r6 |
| 88 | ||
| 89 | /* Do 32 byte chunks */ | |
| 90 | 4: | |
| 91 | err2; std r0,0(r3) | |
| 92 | err2; std r0,8(r3) | |
| 93 | err2; std r0,16(r3) | |
| 94 | err2; std r0,24(r3) | |
| 95 | addi r3,r3,32 | |
| 96 | addi r4,r4,-32 | |
| 97 | bdnz 4b | |
| 98 | ||
| 99 | .Lshort_clear: | |
| 100 | /* up to 31 bytes to go */ | |
| 101 | cmpdi r4,16 | |
| 102 | blt 6f | |
| 103 | err2; std r0,0(r3) | |
| 104 | err2; std r0,8(r3) | |
| 105 | addi r3,r3,16 | |
| 106 | addi r4,r4,-16 | |
| 107 | ||
| 108 | /* Up to 15 bytes to go */ | |
| 109 | 6: mr r8,r3 | |
| 110 | clrldi r4,r4,(64-4) | |
| 111 | mtocrf 0x01,r4 | |
| 112 | bf cr7*4+0,7f | |
| 113 | err1; std r0,0(r3) | |
| 114 | addi r3,r3,8 | |
| 115 | ||
| 116 | 7: bf cr7*4+1,8f | |
| 117 | err1; stw r0,0(r3) | |
| 118 | addi r3,r3,4 | |
| 119 | ||
| 120 | 8: bf cr7*4+2,9f | |
| 121 | err1; sth r0,0(r3) | |
| 122 | addi r3,r3,2 | |
| 123 | ||
| 124 | 9: bf cr7*4+3,10f | |
| 125 | err1; stb r0,0(r3) | |
| 126 | ||
| 127 | 10: li r3,0 | |
| 128 | blr | |
| cf8fb553 AB |
129 | |
| 130 | .Llong_clear: | |
| dab3b8f4 | 131 | LOAD_REG_ADDR(r5, ppc64_caches) |
| cf8fb553 AB |
132 | |
| 133 | bf cr7*4+0,11f | |
| 134 | err2; std r0,0(r3) | |
| 135 | addi r3,r3,8 | |
| 136 | addi r4,r4,-8 | |
| 137 | ||
| bd067f83 BH |
138 | /* Destination is 16 byte aligned, need to get it cache block aligned */ |
| 139 | 11: lwz r7,DCACHEL1LOGBLOCKSIZE(r5) | |
| 140 | lwz r9,DCACHEL1BLOCKSIZE(r5) | |
| cf8fb553 AB |
141 | |
| 142 | /* | |
| 143 | * With worst case alignment the long clear loop takes a minimum | |
| 144 | * of 1 byte less than 2 cachelines. | |
| 145 | */ | |
| 146 | sldi r10,r9,2 | |
| 147 | cmpd r4,r10 | |
| 148 | blt .Lmedium_clear | |
| 149 | ||
| 150 | neg r6,r3 | |
| 151 | addi r10,r9,-1 | |
| 152 | and. r5,r6,r10 | |
| 153 | beq 13f | |
| 154 | ||
| 155 | srdi r6,r5,4 | |
| 156 | mtctr r6 | |
| 157 | mr r8,r3 | |
| 158 | 12: | |
| 159 | err1; std r0,0(r3) | |
| 160 | err1; std r0,8(r3) | |
| 161 | addi r3,r3,16 | |
| 162 | bdnz 12b | |
| 163 | ||
| 164 | sub r4,r4,r5 | |
| 165 | ||
| 166 | 13: srd r6,r4,r7 | |
| 167 | mtctr r6 | |
| 168 | mr r8,r3 | |
| 169 | 14: | |
| 8a583c0a | 170 | err1; dcbz 0,r3 |
| cf8fb553 AB |
171 | add r3,r3,r9 |
| 172 | bdnz 14b | |
| 173 | ||
| 174 | and r4,r4,r10 | |
| 175 | ||
| 176 | cmpdi r4,32 | |
| 177 | blt .Lshort_clear | |
| 178 | b .Lmedium_clear | |
| 61e3acd8 | 179 | EXPORT_SYMBOL(__arch_clear_user) |