rtld_start.S revision 1.1
1 /* $NetBSD: rtld_start.S,v 1.1 1996/12/16 20:38:09 cgd Exp $ */ 2 3 /* 4 * Copyright 1996 Matt Thomas <matt (at) 3am-software.com> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. The name of the author may not be used to endorse or promote products 16 * derived from this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 */ 29 30 #include <machine/asm.h> 31 32 .extern _GLOBAL_OFFSET_TABLE_ 33 34 LEAF(_rtld_start, 0) /* XXX */ 35 .set noreorder 36 br pv, $33 37 $33: LDGP(pv) 38 39 /* save away the stack pointer */ 40 41 lda s0, 0(sp) /* get argc from stack */ 42 lda sp, -16(sp) 43 44 /* save ps_strings pointer */ 45 mov a3, s1 46 47 /* Step 1 -- Figure out the displacement */ 48 49 br t2, $34 /* get our PC */ 50 $34: ldiq t3, $34 /* get where the linker thought we were */ 51 subq t2, t3, t8 /* calculate the displacement */ 52 53 54 /* Step 2 -- Find bounds of global offset table */ 55 56 lda t5, _GLOBAL_OFFSET_TABLE_ 57 addq t8, t5, t9 /* add the displacement */ 58 #if defined(OLD_GOT) 59 ldq t4, 0(t9) /* Get the address of dynamic table */ 60 #else 61 lda t4, _DYNAMIC 62 #endif 63 addq t8, t4, t10 /* add the displacement */ 64 65 /* 66 * Step 3 -- Every entry in the global offset table needs to 67 * modified for the displacement before any code will work. 68 */ 69 70 $35: ldq t1, 0(t9) /* load the value */ 71 addq t8, t1, t1 /* add the displacement */ 72 stq t1, 0(t9) /* save the new value */ 73 lda t9, 8(t9) /* point to next entry */ 74 cmpult t9, t10, t1 /* are we done? */ 75 bne t1, $35 /* no, do more */ 76 77 /* 78 * Ya! Things are far enough so we can do some dynamic linking! 79 */ 80 81 lda a0, -16(s0) 82 CALL(_rtld) /* v0 = _rtld(sp); */ 83 84 ldq a1, -16(s0) /* our atexit function */ 85 ldq a2, -8(s0) /* obj_main entry */ 86 lda sp, 16(sp) /* readjust our stack */ 87 mov s0, a0 /* stack pointer */ 88 mov s1, a3 /* ps_strings pointer */ 89 mov v0, t12 90 jsr ra, (v0), 0 /* (*_start)(sp, cleanup, obj); */ 91 ldgp gp, 0(ra) 92 93 CALL(exit) 94 halt 95 END(_rtld_start) 96 97 .set noat 98 .globl _rtld_bind_start 99 .ent _rtld_bind_start 100 _rtld_bind_start: 101 102 lda sp, -168(sp) 103 .frame sp, 168, $26 104 /* Preserve all registers that C normally doesn't. */ 105 stq $26, 0(sp) 106 stq $0, 8(sp) 107 stq $1, 16(sp) 108 stq $2, 24(sp) 109 stq $3, 32(sp) 110 stq $4, 40(sp) 111 stq $5, 48(sp) 112 stq $6, 56(sp) 113 stq $7, 64(sp) 114 stq $8, 72(sp) 115 stq $16, 80(sp) 116 stq $17, 88(sp) 117 stq $18, 96(sp) 118 stq $19, 104(sp) 119 stq $20, 112(sp) 120 stq $21, 120(sp) 121 stq $22, 128(sp) 122 stq $23, 136(sp) 123 stq $24, 144(sp) 124 stq $25, 152(sp) 125 stq $29, 160(sp) 126 .mask 0x27ff01ff, -168 127 /* Set up our $gp */ 128 br gp, $100 129 $100: ldgp gp, 0(gp) 130 .prologue 1 131 /* Set up the arguments for _rtld_bind. */ 132 ldq a0, 8(t12) /* object structure */ 133 mov at_reg, a1 /* offset of reloc entry */ 134 CALL(_rtld_bind) 135 136 /* Move the destination address into position. */ 137 mov $0, $27 138 /* Restore program registers. */ 139 ldq $26, 0(sp) 140 ldq $0, 8(sp) 141 ldq $1, 16(sp) 142 ldq $2, 24(sp) 143 ldq $3, 32(sp) 144 ldq $4, 40(sp) 145 ldq $5, 48(sp) 146 ldq $6, 56(sp) 147 ldq $7, 64(sp) 148 ldq $8, 72(sp) 149 ldq $16, 80(sp) 150 ldq $17, 88(sp) 151 ldq $18, 96(sp) 152 ldq $19, 104(sp) 153 ldq $20, 112(sp) 154 ldq $21, 120(sp) 155 ldq $22, 128(sp) 156 ldq $23, 136(sp) 157 ldq $24, 144(sp) 158 ldq $25, 152(sp) 159 ldq $29, 160(sp) 160 /* Flush the Icache after having modified the .plt code. */ 161 imb 162 /* Clean up and turn control to the destination */ 163 lda sp, 168(sp) 164 jmp $31, ($27) 165 .end _rtld_bind_start 166 167 168 169 170
Indexes created Thu Oct 02 07:10:07 GMT 2025