1/* 2 * Copyright (C) 2008 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29#include <private/bionic_asm.h> 30#include <private/libc_events.h> 31 32/* 33 * This code assumes it is running on a processor that supports all arm v7 34 * instructions and that supports neon instructions. 35 */ 36 37 .fpu neon 38 .syntax unified 39 40ENTRY(__memset_chk) 41 cmp r2, r3 42 bls .L_done 43 44 // Preserve lr for backtrace. 45 push {lr} 46 .cfi_def_cfa_offset 4 47 .cfi_rel_offset lr, 0 48 49 ldr r0, error_message 50 ldr r1, error_code 511: 52 add r0, pc 53 bl __fortify_chk_fail 54error_code: 55 .word BIONIC_EVENT_MEMSET_BUFFER_OVERFLOW 56error_message: 57 .word error_string-(1b+8) 58END(__memset_chk) 59 60ENTRY(bzero) 61 mov r2, r1 62 mov r1, #0 63 64.L_done: 65 // Fall through to memset... 66END(bzero) 67 68/* memset() returns its first argument. */ 69ENTRY(memset) 70 // The neon memset only wins for less than 132. 71 cmp r2, #132 72 bhi .L_memset_large_copy 73 74 mov r3, r0 75 vdup.8 q0, r1 76 77 /* make sure we have at least 32 bytes to write */ 78 subs r2, r2, #32 79 blo 2f 80 vmov q1, q0 81 821: /* The main loop writes 32 bytes at a time */ 83 subs r2, r2, #32 84 vst1.8 {d0 - d3}, [r3]! 85 bhs 1b 86 872: /* less than 32 left */ 88 add r2, r2, #32 89 tst r2, #0x10 90 beq 3f 91 92 // writes 16 bytes, 128-bits aligned 93 vst1.8 {d0, d1}, [r3]! 943: /* write up to 15-bytes (count in r2) */ 95 movs ip, r2, lsl #29 96 bcc 1f 97 vst1.8 {d0}, [r3]! 981: bge 2f 99 vst1.32 {d0[0]}, [r3]! 1002: movs ip, r2, lsl #31 101 strbmi r1, [r3], #1 102 strbcs r1, [r3], #1 103 strbcs r1, [r3], #1 104 bx lr 105 106.L_memset_large_copy: 107 /* compute the offset to align the destination 108 * offset = (4-(src&3))&3 = -src & 3 109 */ 110 stmfd sp!, {r0, r4-r7, lr} 111 .cfi_def_cfa_offset 24 112 .cfi_rel_offset r0, 0 113 .cfi_rel_offset r4, 4 114 .cfi_rel_offset r5, 8 115 .cfi_rel_offset r6, 12 116 .cfi_rel_offset r7, 16 117 .cfi_rel_offset lr, 20 118 119 rsb r3, r0, #0 120 ands r3, r3, #3 121 cmp r3, r2 122 movhi r3, r2 123 124 /* splat r1 */ 125 mov r1, r1, lsl #24 126 orr r1, r1, r1, lsr #8 127 orr r1, r1, r1, lsr #16 128 129 movs r12, r3, lsl #31 130 strbcs r1, [r0], #1 /* can't use strh (alignment unknown) */ 131 strbcs r1, [r0], #1 132 strbmi r1, [r0], #1 133 subs r2, r2, r3 134 popls {r0, r4-r7, pc} /* return */ 135 136 /* align the destination to a cache-line */ 137 mov r12, r1 138 mov lr, r1 139 mov r4, r1 140 mov r5, r1 141 mov r6, r1 142 mov r7, r1 143 144 rsb r3, r0, #0 145 ands r3, r3, #0x1C 146 beq 3f 147 cmp r3, r2 148 andhi r3, r2, #0x1C 149 sub r2, r2, r3 150 151 /* conditionally writes 0 to 7 words (length in r3) */ 152 movs r3, r3, lsl #28 153 stmcs r0!, {r1, lr} 154 stmcs r0!, {r1, lr} 155 stmmi r0!, {r1, lr} 156 movs r3, r3, lsl #2 157 strcs r1, [r0], #4 158 1593: 160 subs r2, r2, #32 161 mov r3, r1 162 bmi 2f 1631: subs r2, r2, #32 164 stmia r0!, {r1,r3,r4,r5,r6,r7,r12,lr} 165 bhs 1b 1662: add r2, r2, #32 167 168 /* conditionally stores 0 to 31 bytes */ 169 movs r2, r2, lsl #28 170 stmcs r0!, {r1,r3,r12,lr} 171 stmmi r0!, {r1, lr} 172 movs r2, r2, lsl #2 173 strcs r1, [r0], #4 174 strhmi r1, [r0], #2 175 movs r2, r2, lsl #2 176 strbcs r1, [r0] 177 ldmfd sp!, {r0, r4-r7, pc} 178END(memset) 179 180 .data 181error_string: 182 .string "memset: prevented write past end of buffer" 183