1 /* 2 * Copyright (C) 2013 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 31 .syntax unified 32 .fpu neon 33 .thumb 34 .thumb_func 35 36 // Get the length of src string, then get the source of the dst string. 37 // Check that the two lengths together don't exceed the threshold, then 38 // do a memcpy of the data. 39 ENTRY(__strcat_chk) 40 pld [r0, #0] 41 push {r0, lr} 42 .cfi_def_cfa_offset 8 43 .cfi_rel_offset r0, 0 44 .cfi_rel_offset lr, 4 45 push {r4, r5} 46 .cfi_adjust_cfa_offset 8 47 .cfi_rel_offset r4, 0 48 .cfi_rel_offset r5, 4 49 50 mov lr, r2 51 52 // Save the dst register to r5 53 mov r5, r0 54 55 // Zero out r4 56 eor r4, r4, r4 57 58 // r1 contains the address of the string to count. 59 .L_strlen_start: 60 mov r0, r1 61 62 ands r3, r0, #7 63 bne .L_align_src 64 65 .p2align 2 66 .L_mainloop: 67 ldmia r1!, {r2, r3} 68 69 pld [r1, #64] 70 71 sub ip, r2, #0x01010101 72 bic ip, ip, r2 73 ands ip, ip, #0x80808080 74 bne .L_zero_in_first_register 75 76 sub ip, r3, #0x01010101 77 bic ip, ip, r3 78 ands ip, ip, #0x80808080 79 bne .L_zero_in_second_register 80 b .L_mainloop 81 82 .L_zero_in_first_register: 83 sub r3, r1, r0 84 // Check for zero in byte 0. 85 lsls r2, ip, #17 86 beq .L_check_byte1_reg1 87 88 sub r3, r3, #8 89 b .L_finish 90 91 .L_check_byte1_reg1: 92 bcc .L_check_byte2_reg1 93 94 sub r3, r3, #7 95 b .L_finish 96 97 .L_check_byte2_reg1: 98 // Check for zero in byte 2. 99 tst ip, #0x800000 100 it ne 101 subne r3, r3, #6 102 bne .L_finish 103 sub r3, r3, #5 104 b .L_finish 105 106 .L_zero_in_second_register: 107 sub r3, r1, r0 108 // Check for zero in byte 0. 109 lsls r2, ip, #17 110 beq .L_check_byte1_reg2 111 112 sub r3, r3, #4 113 b .L_finish 114 115 .L_check_byte1_reg2: 116 bcc .L_check_byte2_reg2 117 118 sub r3, r3, #3 119 b .L_finish 120 121 .L_check_byte2_reg2: 122 // Check for zero in byte 2. 123 tst ip, #0x800000 124 it ne 125 subne r3, r3, #2 126 bne .L_finish 127 sub r3, r3, #1 128 b .L_finish 129 130 .L_align_src: 131 // Align to a double word (64 bits). 132 rsb r3, r3, #8 133 lsls ip, r3, #31 134 beq .L_align_to_32 135 136 ldrb r2, [r1], #1 137 cbz r2, .L_done 138 139 .L_align_to_32: 140 bcc .L_align_to_64 141 142 ldrb r2, [r1], #1 143 cbz r2, .L_done 144 ldrb r2, [r1], #1 145 cbz r2, .L_done 146 147 .L_align_to_64: 148 tst r3, #4 149 beq .L_mainloop 150 ldr r2, [r1], #4 151 152 sub ip, r2, #0x01010101 153 bic ip, ip, r2 154 ands ip, ip, #0x80808080 155 bne .L_zero_in_second_register 156 b .L_mainloop 157 158 .L_done: 159 sub r3, r1, r0 160 sub r3, r3, #1 161 162 .L_finish: 163 cmp r4, #0 164 bne .L_strlen_done 165 166 // Time to get the dst string length. 167 mov r1, r5 168 169 // Save the original source address to r5. 170 mov r5, r0 171 172 // Save the current length (adding 1 for the terminator). 173 add r4, r3, #1 174 b .L_strlen_start 175 176 // r0 holds the pointer to the dst string. 177 // r3 holds the dst string length. 178 // r4 holds the src string length + 1. 179 .L_strlen_done: 180 add r2, r3, r4 181 cmp r2, lr 182 itt hi 183 movhi r0, lr 184 bhi __strcat_chk_fail 185 186 // Set up the registers for the memcpy code. 187 mov r1, r5 188 pld [r1, #64] 189 mov r2, r4 190 add r0, r0, r3 191 pop {r4, r5} 192 193 // Fall through into the memcpy_base function. 194 END(__strcat_chk) 195 196 #define MEMCPY_BASE __strcat_chk_memcpy_base 197 #define MEMCPY_BASE_ALIGNED __strcat_chk_memcpy_base_aligned 198 #include "memcpy_base.S" 199
