1 /* $NetBSD: rtld_start.S,v 1.17 2011/09/26 01:52:22 mrg Exp $ */ 2 3 /*- 4 * Copyright (C) 1998 Tsubai Masanari 5 * Portions copyright 2002 Charles M. Hannum <root (at) ihack.net> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. The name of the author may not be used to endorse or promote products 17 * derived from this software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #include <machine/asm.h> 32 33 .globl _rtld_start 34 .globl _rtld 35 36 .text 37 38 _rtld_start: 39 stwu %r1,-48(%r1) 40 stw %r3,12(%r1) # argc 41 stw %r4,16(%r1) # argv 42 stw %r5,20(%r1) # envp 43 /* stw %r6,24(%r1) # obj (always 0) */ 44 /* stw %r7,28(%r1) # cleanup (always 0) */ 45 stw %r8,32(%r1) # ps_strings 46 47 bcl 20,31,1f 48 1: mflr %r30 49 mr %r3,%r30 # save for _DYNAMIC 50 addis %r30,%r30,_GLOBAL_OFFSET_TABLE_-1b@ha 51 addi %r30,%r30,_GLOBAL_OFFSET_TABLE_-1b@l 52 addis %r3,%r3,_DYNAMIC-1b@ha # get _DYNAMIC actual address 53 addi %r3,%r3,_DYNAMIC-1b@l 54 lwz %r28,0(%r30) # get base-relative &_DYNAMIC 55 sub %r28,%r3,%r28 # r28 = relocbase 56 mr %r4,%r28 # r4 = relocbase 57 bl _rtld_relocate_nonplt_self 58 59 lwz %r3,16(%r1) 60 addi %r3,%r3,-12 # sp = &argv[-3] /* XXX */ 61 mr %r4,%r28 # r4 = relocbase 62 bl _rtld # _start = _rtld(sp, relocbase) 63 mtlr %r3 64 65 lwz %r3,12(%r1) # argc 66 lwz %r4,16(%r1) # argv 67 lwz %r5,20(%r1) # envp 68 lwz %r6,-8(%r4) # obj = sp[1] (== argv[-2]) 69 lwz %r7,-12(%r4) # cleanup = sp[0] (== argv[-3]) 70 lwz %r8,32(%r1) # ps_strings 71 72 addi %r1,%r1,48 73 blrl # _start(argc, argv, envp, obj, cleanup, ps_strings) 74 75 li %r0,1 # _exit() 76 sc 77 78 END(_rtld_start) 79 80 .globl _rtld_bind 81 82 /* 83 * secure-plt expects %r11 to be the offset to the rela entry. 84 * bss-plt expects %r11 to be index of the rela entry. 85 * So for bss-plt, we multiply the index by 12 to get the offset. 86 */ 87 ENTRY_NOPROFILE(_rtld_bind_secureplt_start) 88 stwu %r1,-160(%r1) 89 stw %r0,20(%r1) 90 91 /* 92 * Instead of division which is costly we will use multiplicative 93 * inverse. a / n = ((a * inv(n)) >> 32) 94 * where inv(n) = (0x100000000 + n - 1) / n 95 */ 96 mr %r0,%r11 97 lis %r11,0x15555556@h # load multiplicative inverse of 12 98 ori %r11,%r11,0x15555556@l 99 mulhwu %r11,%r11,%r0 # get high half of multiplication 100 101 b 1f 102 ENTRY_NOPROFILE(_rtld_bind_bssplt_start) 103 stwu %r1,-160(%r1) 104 105 stw %r0,20(%r1) 106 1: 107 mflr %r0 108 stw %r0,16(%r1) # save lr 109 mfcr %r0 110 stw %r0,12(%r1) # save cr 111 stmw %r3,24(%r1) # save r3-r31 112 113 mr %r3,%r12 # obj 114 mr %r4,%r11 # reloff 115 bl _rtld_bind # _rtld_bind(obj, reloff) 116 mtctr %r3 117 118 lmw %r3,24(%r1) # load r3-r31 119 lwz %r0,12(%r1) # restore cr 120 mtcr %r0 121 lwz %r0,16(%r1) # restore lr 122 mtlr %r0 123 lwz %r0,20(%r1) 124 125 addi %r1,%r1,160 126 bctr 127 END(_rtld_bind_secureplt_start) 128 129 .globl _rtld_powerpc_pltcall 130 .globl _rtld_powerpc_pltresolve 131 132 _rtld_powerpc_pltcall: 133 slwi %r11,%r11,2 134 addis %r11,%r11,0 # addis 11,11,jmptab@ha 135 lwz %r11,0(%r11) # lwz 11,jmptab@l(11) 136 mtctr %r11 137 bctr 138 139 _rtld_powerpc_pltresolve: 140 lis %r12,0 # lis 12,_rtld_bind_bssplt_start@ha 141 addi %r12,%r12,0 # addi 12,12,_rtld_bind_bssplt_start@l 142 mtctr %r12 143 lis %r12,0 # lis 12,obj@ha 144 addi %r12,%r12,0 # addi 12,12,obj@l 145 bctr 146
Indexes created Tue Sep 23 02:09:52 GMT 2025