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 * Optimized memset() for ARM. 34 * 35 * memset() returns its first argument. 36 */ 37 38 .syntax unified 39 40ENTRY(__memset_chk) 41 cmp r2, r3 42 bls done 43 44 ldr r0, error_message 45 ldr r1, error_code 461: 47 add r0, pc 48 bl __fortify_chk_fail 49error_code: 50 .word BIONIC_EVENT_MEMSET_BUFFER_OVERFLOW 51error_message: 52 .word error_string-(1b+8) 53 54END(__memset_chk) 55 56ENTRY(bzero) 57 mov r2, r1 58 mov r1, #0 59 60done: 61 // Fall through to memset... 62END(bzero) 63 64ENTRY(memset) 65 /* compute the offset to align the destination 66 * offset = (4-(src&3))&3 = -src & 3 67 */ 68 .save {r0, r4-r7, lr} 69 stmfd sp!, {r0, r4-r7, lr} 70 rsb r3, r0, #0 71 ands r3, r3, #3 72 cmp r3, r2 73 movhi r3, r2 74 75 /* splat r1 */ 76 mov r1, r1, lsl #24 77 orr r1, r1, r1, lsr #8 78 orr r1, r1, r1, lsr #16 79 80 movs r12, r3, lsl #31 81 strbcs r1, [r0], #1 /* can't use strh (alignment unknown) */ 82 strbcs r1, [r0], #1 83 strbmi r1, [r0], #1 84 subs r2, r2, r3 85 popls {r0, r4-r7, pc} /* return */ 86 87 /* align the destination to a cache-line */ 88 mov r12, r1 89 mov lr, r1 90 mov r4, r1 91 mov r5, r1 92 mov r6, r1 93 mov r7, r1 94 95 rsb r3, r0, #0 96 ands r3, r3, #0x1C 97 beq 3f 98 cmp r3, r2 99 andhi r3, r2, #0x1C 100 sub r2, r2, r3 101 102 /* conditionally writes 0 to 7 words (length in r3) */ 103 movs r3, r3, lsl #28 104 stmcs r0!, {r1, lr} 105 stmcs r0!, {r1, lr} 106 stmmi r0!, {r1, lr} 107 movs r3, r3, lsl #2 108 strcs r1, [r0], #4 109 1103: 111 subs r2, r2, #32 112 mov r3, r1 113 bmi 2f 1141: subs r2, r2, #32 115 stmia r0!, {r1,r3,r4,r5,r6,r7,r12,lr} 116 bhs 1b 1172: add r2, r2, #32 118 119 /* conditionally stores 0 to 31 bytes */ 120 movs r2, r2, lsl #28 121 stmcs r0!, {r1,r3,r12,lr} 122 stmmi r0!, {r1, lr} 123 movs r2, r2, lsl #2 124 strcs r1, [r0], #4 125 strhmi r1, [r0], #2 126 movs r2, r2, lsl #2 127 strbcs r1, [r0] 128 ldmfd sp!, {r0, r4-r7, pc} 129END(memset) 130 131 .data 132error_string: 133 .string "memset: prevented write past end of buffer" 134