1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * linux/arch/arm/lib/copy_template.s 4 * 5 * Code template for optimized memory copy functions 6 * 7 * Author: Nicolas Pitre 8 * Created: Sep 28, 2005 9 * Copyright: MontaVista Software, Inc. 10 */ 11 12/* 13 * Theory of operation 14 * ------------------- 15 * 16 * This file provides the core code for a forward memory copy used in 17 * the implementation of memcopy(), copy_to_user() and copy_from_user(). 18 * 19 * The including file must define the following accessor macros 20 * according to the need of the given function: 21 * 22 * ldr1w ptr reg abort 23 * 24 * This loads one word from 'ptr', stores it in 'reg' and increments 25 * 'ptr' to the next word. The 'abort' argument is used for fixup tables. 26 * 27 * ldr4w ptr reg1 reg2 reg3 reg4 abort 28 * ldr8w ptr, reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort 29 * 30 * This loads four or eight words starting from 'ptr', stores them 31 * in provided registers and increments 'ptr' past those words. 32 * The'abort' argument is used for fixup tables. 33 * 34 * ldr1b ptr reg cond abort 35 * 36 * Similar to ldr1w, but it loads a byte and increments 'ptr' one byte. 37 * It also must apply the condition code if provided, otherwise the 38 * "al" condition is assumed by default. 39 * 40 * str1w ptr reg abort 41 * str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort 42 * str1b ptr reg cond abort 43 * 44 * Same as their ldr* counterparts, but data is stored to 'ptr' location 45 * rather than being loaded. 46 * 47 * enter reg1 reg2 48 * 49 * Preserve the provided registers on the stack plus any additional 50 * data as needed by the implementation including this code. Called 51 * upon code entry. 52 * 53 * usave reg1 reg2 54 * 55 * Unwind annotation macro is corresponding for 'enter' macro. 56 * It tell unwinder that preserved some provided registers on the stack 57 * and additional data by a prior 'enter' macro. 58 * 59 * exit reg1 reg2 60 * 61 * Restore registers with the values previously saved with the 62 * 'preserv' macro. Called upon code termination. 63 * 64 * LDR1W_SHIFT 65 * STR1W_SHIFT 66 * 67 * Correction to be applied to the "ip" register when branching into 68 * the ldr1w or str1w instructions (some of these macros may expand to 69 * than one 32bit instruction in Thumb-2) 70 */ 71 72 UNWIND( .fnstart ) 73 enter r4, UNWIND(fpreg,) lr 74 UNWIND( .setfp fpreg, sp ) 75 UNWIND( mov fpreg, sp ) 76 77 subs r2, r2, #4 78 blt 8f 79 ands ip, r0, #3 80 PLD( pld [r1, #0] ) 81 bne 9f 82 ands ip, r1, #3 83 bne 10f 84 851: subs r2, r2, #(28) 86 stmfd sp!, {r5, r6, r8, r9} 87 blt 5f 88 89 CALGN( ands ip, r0, #31 ) 90 CALGN( rsb r3, ip, #32 ) 91 CALGN( sbcsne r4, r3, r2 ) @ C is always set here 92 CALGN( bcs 2f ) 93 CALGN( adr r4, 6f ) 94 CALGN( subs r2, r2, r3 ) @ C gets set 95 CALGN( add pc, r4, ip ) 96 97 PLD( pld [r1, #0] ) 982: PLD( subs r2, r2, #96 ) 99 PLD( pld [r1, #28] ) 100 PLD( blt 4f ) 101 PLD( pld [r1, #60] ) 102 PLD( pld [r1, #92] ) 103 1043: PLD( pld [r1, #124] ) 1054: ldr8w r1, r3, r4, r5, r6, r8, r9, ip, lr, abort=20f 106 subs r2, r2, #32 107 str8w r0, r3, r4, r5, r6, r8, r9, ip, lr, abort=20f 108 bge 3b 109 PLD( cmn r2, #96 ) 110 PLD( bge 4b ) 111 1125: ands ip, r2, #28 113 rsb ip, ip, #32 114#if LDR1W_SHIFT > 0 115 lsl ip, ip, #LDR1W_SHIFT 116#endif 117 addne pc, pc, ip @ C is always clear here 118 b 7f 1196: 120 .rept (1 << LDR1W_SHIFT) 121 W(nop) 122 .endr 123 ldr1w r1, r3, abort=20f 124 ldr1w r1, r4, abort=20f 125 ldr1w r1, r5, abort=20f 126 ldr1w r1, r6, abort=20f 127 ldr1w r1, r8, abort=20f 128 ldr1w r1, r9, abort=20f 129 ldr1w r1, lr, abort=20f 130 131#if LDR1W_SHIFT < STR1W_SHIFT 132 lsl ip, ip, #STR1W_SHIFT - LDR1W_SHIFT 133#elif LDR1W_SHIFT > STR1W_SHIFT 134 lsr ip, ip, #LDR1W_SHIFT - STR1W_SHIFT 135#endif 136 add pc, pc, ip 137 nop 138 .rept (1 << STR1W_SHIFT) 139 W(nop) 140 .endr 141 str1w r0, r3, abort=20f 142 str1w r0, r4, abort=20f 143 str1w r0, r5, abort=20f 144 str1w r0, r6, abort=20f 145 str1w r0, r8, abort=20f 146 str1w r0, r9, abort=20f 147 str1w r0, lr, abort=20f 148 149 CALGN( bcs 2b ) 150 1517: ldmfd sp!, {r5, r6, r8, r9} 152 1538: movs r2, r2, lsl #31 154 ldr1b r1, r3, ne, abort=21f 155 ldr1b r1, r4, cs, abort=21f 156 ldr1b r1, ip, cs, abort=21f 157 str1b r0, r3, ne, abort=21f 158 str1b r0, r4, cs, abort=21f 159 str1b r0, ip, cs, abort=21f 160 161 exit r4, UNWIND(fpreg,) pc 162 1639: rsb ip, ip, #4 164 cmp ip, #2 165 ldr1b r1, r3, gt, abort=21f 166 ldr1b r1, r4, ge, abort=21f 167 ldr1b r1, lr, abort=21f 168 str1b r0, r3, gt, abort=21f 169 str1b r0, r4, ge, abort=21f 170 subs r2, r2, ip 171 str1b r0, lr, abort=21f 172 blt 8b 173 ands ip, r1, #3 174 beq 1b 175 17610: bic r1, r1, #3 177 cmp ip, #2 178 ldr1w r1, lr, abort=21f 179 beq 17f 180 bgt 18f 181 182 183 .macro forward_copy_shift pull push 184 185 subs r2, r2, #28 186 blt 14f 187 188 CALGN( ands ip, r0, #31 ) 189 CALGN( rsb ip, ip, #32 ) 190 CALGN( sbcsne r4, ip, r2 ) @ C is always set here 191 CALGN( subcc r2, r2, ip ) 192 CALGN( bcc 15f ) 193 19411: stmfd sp!, {r5, r6, r8 - r10} 195 196 PLD( pld [r1, #0] ) 197 PLD( subs r2, r2, #96 ) 198 PLD( pld [r1, #28] ) 199 PLD( blt 13f ) 200 PLD( pld [r1, #60] ) 201 PLD( pld [r1, #92] ) 202 20312: PLD( pld [r1, #124] ) 20413: ldr4w r1, r4, r5, r6, r8, abort=19f 205 mov r3, lr, lspull #\pull 206 subs r2, r2, #32 207 ldr4w r1, r9, r10, ip, lr, abort=19f 208 orr r3, r3, r4, lspush #\push 209 mov r4, r4, lspull #\pull 210 orr r4, r4, r5, lspush #\push 211 mov r5, r5, lspull #\pull 212 orr r5, r5, r6, lspush #\push 213 mov r6, r6, lspull #\pull 214 orr r6, r6, r8, lspush #\push 215 mov r8, r8, lspull #\pull 216 orr r8, r8, r9, lspush #\push 217 mov r9, r9, lspull #\pull 218 orr r9, r9, r10, lspush #\push 219 mov r10, r10, lspull #\pull 220 orr r10, r10, ip, lspush #\push 221 mov ip, ip, lspull #\pull 222 orr ip, ip, lr, lspush #\push 223 str8w r0, r3, r4, r5, r6, r8, r9, r10, ip, abort=19f 224 bge 12b 225 PLD( cmn r2, #96 ) 226 PLD( bge 13b ) 227 228 ldmfd sp!, {r5, r6, r8 - r10} 229 23014: ands ip, r2, #28 231 beq 16f 232 23315: mov r3, lr, lspull #\pull 234 ldr1w r1, lr, abort=21f 235 subs ip, ip, #4 236 orr r3, r3, lr, lspush #\push 237 str1w r0, r3, abort=21f 238 bgt 15b 239 CALGN( cmp r2, #0 ) 240 CALGN( bge 11b ) 241 24216: sub r1, r1, #(\push / 8) 243 b 8b 244 245 .endm 246 247 248 forward_copy_shift pull=8 push=24 249 25017: forward_copy_shift pull=16 push=16 251 25218: forward_copy_shift pull=24 push=8 253 254 UNWIND( .fnend ) 255 256/* 257 * Abort preamble and completion macros. 258 * If a fixup handler is required then those macros must surround it. 259 * It is assumed that the fixup code will handle the private part of 260 * the exit macro. 261 */ 262 263 .macro copy_abort_preamble 26419: ldmfd sp!, {r5, r6, r8 - r10} 265 b 21f 26620: ldmfd sp!, {r5, r6, r8, r9} 26721: 268 .endm 269 270 .macro copy_abort_end 271 ldmfd sp!, {r4, UNWIND(fpreg,) pc} 272 .endm 273 274