1/* $NetBSD: rtld_start.S,v 1.6 2008/04/28 20:23:03 martin Exp $ */ 2 3/*- 4 * Copyright (c) 2002 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Matt Fredette. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32#include <machine/asm.h> 33#define _LOCORE /* XXX fredette we MUST get rid of this */ 34#include <machine/frame.h> 35#undef _LOCORE 36 37 .import _GLOBAL_OFFSET_TABLE_ 38 39ENTRY($rtld_start,HPPA_FRAME_SIZE) 40 41 /* Start stack calling convention. */ 42 copy %r3, %r1 43 copy %sp, %r3 44 stw,ma %r1, HPPA_FRAME_SIZE(%sp) 45 46 /* 47 * Save our single argument, the ps_strings pointer. 48 * We'll need this twice later: once to call _rtld, 49 * and again to transfer to the program's entry point. 50 */ 51 stw %arg0, HPPA_FRAME_ARG(0)(%r3) 52 53 /* 54 * We can't move to C until we relocate at least the 55 * Global Offset Table. Even finding the GOT is tricky 56 * without inadvertently causing the linker to make 57 * relocations for this part of the text segment. 58 */ 59 60 bl L$lpc1, %r19 61 depi 0, 31, 2, %r19 62L$lpc1: addil L'_DYNAMIC - ($PIC_pcrel$0 - 8), %r19 63 ldo R'_DYNAMIC - ($PIC_pcrel$0 - 12)(%r1),%arg0 64 65 /* 66 * Load the absolute address of the beginning of the 67 * GOT into %r19, the shared library linkage table 68 * register, leaving it ready-to-use by the dynamic 69 * linker C code. 70 */ 71 addil L'_GLOBAL_OFFSET_TABLE_ - ($PIC_pcrel$0 - 16), %r19 72 ldo R'_GLOBAL_OFFSET_TABLE_ - ($PIC_pcrel$0 - 20)(%r1),%r19 73 74 /* 75 * The linker sets the first entry in the GOT to the 76 * unrelocated address of _DYNAMIC. Subtract this 77 * from the absolute address of _DYNAMIC to get our 78 * relocbase. 79 */ 80 ldw 0(%r19), %arg1 81 sub %arg0, %arg1, %arg1 ; %arg1 = relocbase 82 bl _rtld_relocate_nonplt_self, %rp 83 copy %arg1, %r4 ; save for later 84 85 /* 86 * Recover the ps_strings pointer, and take out the 87 * ps_argvstr member. 88 */ 89 ldw HPPA_FRAME_ARG(0)(%r3), %arg0 ; ps_strings 90 ldw 0(%arg0), %arg0 ; ps_argvstr member first in struct 91 92 /* 93 * ps_argvstr - 4 would get us a pointer to argc, 94 * comparable to the initial stack pointer on 95 * architectures where the stack grows down. 96 * Subtracting an additional eight creates the 97 * storage for obj and cleanup that _rtld needs. 98 */ 99 ldo -12(%arg0), %arg0 100 stw %arg0, HPPA_FRAME_ARG(1)(%r3) 101 102 /* Call _rtld, copying relocbase into arg1. */ 103 bl _rtld, %rp 104 copy %r4, %arg1 ; %arg1 = relocbase 105 106 /* Prepare the arguments for the entry point. */ 107 ldw HPPA_FRAME_ARG(1)(%r3), %r1 108 ldw HPPA_FRAME_ARG(0)(%r3), %arg0 ; ps_strings 109 ldw 0(%r1), %arg1 ; cleanup 110 ldw 4(%r1), %arg2 ; obj 111 112 /* End stack calling convention. */ 113 ldo HPPA_FRAME_SIZE(%r3), %sp 114 ldw,mb -HPPA_FRAME_SIZE(%sp), %r3 115 116 /* Go for it. */ 117 bv %r0(%ret0) 118 copy %r0, %rp 119EXIT($rtld_start) 120 121/* 122 * This does our setup for an object's GOT. %arg0 is the 123 * Obj_Entry * for the object, and %arg1 is its GOT pointer. 124 */ 125LEAF_ENTRY(__rtld_setup_hppa_pltgot) 126 127 /* 128 * The second entry of the GOT is reserved for 129 * the dynamic linker. We put the Obj_Entry * 130 * for the object in there. 131 */ 132 stw %arg0, 4(%arg1) 133 134 /* 135 * Fill the fixup_func and fixup_ltp members of 136 * the PLT stub. This stub is inserted by the 137 * linker immediately before the GOT. We use 138 * this stub to enter our binder. 139 */ 140 141 bl L$lpc2, %arg0 142 depi 0, 31, 2, %arg0 143L$lpc2: addil L'_rtld_bind_start - ($PIC_pcrel$0 - 8), %arg0 144 ldo R'_rtld_bind_start - ($PIC_pcrel$0 - 12)(%r1),%arg0 145 146 stw %arg0, -8(%arg1) 147 bv %r0(%rp) 148 stw %r19, -4(%arg1) 149EXIT(__rtld_hppa_setup_pltgot) 150 151/* 152 * In order to support lazy binding, this implementation of 153 * _rtld_bind_start is very closely tied to the shared-library 154 * call stub and the PLT stub, both inserted by the linker. 155 */ 156ENTRY(_rtld_bind_start,HPPA_FRAME_SIZE) 157 158 /* Start stack calling convention. */ 159 copy %r3, %r1 160 copy %sp, %r3 161 162 stw,ma %r1, HPPA_FRAME_SIZE(%sp) 163 164 /* 165 * We have to save all calling convention registers 166 * that are set by the caller, because we have to 167 * restore them before transferring to the bound 168 * function. Note that this includes %ret0 and %ret1, 169 * because they can have meaning on entry to a function. 170 */ 171 stw %rp, HPPA_FRAME_CRP(%r3) 172 stw %arg0, HPPA_FRAME_ARG(0)(%r3) 173 stw %arg1, HPPA_FRAME_ARG(1)(%r3) 174 stw %arg2, HPPA_FRAME_ARG(2)(%r3) 175 stw %arg3, HPPA_FRAME_ARG(3)(%r3) 176 /* 0(%r3) is filled with the saved %r3 above */ 177 stw %ret0, 4(%r3) 178 stw %ret1, 8(%r3) 179 180 /* 181 * The linker PLT stub loads %r20 with (GOT - 8) for 182 * the object that needs binding done. The second entry 183 * of the GOT is reserved for the dynamic linker's use, 184 * and we previously stashed the object's Obj_Entry * 185 * there. 186 */ 187 ldw 12(%r20), %arg0 188 189 /* 190 * The linker shared-library call stub loads %r19 from 191 * the shared linkage member of the PLT entry. We 192 * previously stashed the reloff of the relocation there. 193 */ 194 copy %r19, %arg1 195 196 /* 197 * The linker PLT stub loads %r21 with the fixup_ltp 198 * word in itself. We previously stashed our %r19 199 * value there. 200 */ 201 bl _rtld_bind, %rp 202 copy %r21, %r19 203 204 /* 205 * Our hppa version of _rtld_bind returns to us the 206 * address of the PLT entry that it fixed up. Load 207 * the function address and shared linkage for the 208 * newly bound function. 209 */ 210 ldw 0(%ret0), %r21 211 ldw 4(%ret0), %r19 212 213 /* Restore registers saved above. */ 214 ldw HPPA_FRAME_CRP(%r3), %rp 215 ldw HPPA_FRAME_ARG(0)(%r3), %arg0 216 ldw HPPA_FRAME_ARG(1)(%r3), %arg1 217 ldw HPPA_FRAME_ARG(2)(%r3), %arg2 218 ldw HPPA_FRAME_ARG(3)(%r3), %arg3 219 ldw 4(%r3), %ret0 220 ldw 8(%r3), %ret1 221 222 /* End stack calling convention. */ 223 ldo HPPA_FRAME_SIZE(%r3), %sp 224 ldw,mb -HPPA_FRAME_SIZE(%sp), %r3 225 226 /* Transfer to the function. */ 227 bv %r0(%r21) 228 nop 229EXIT(_rtld_bind_start) 230