1107572Sgrehan/* $NetBSD: rtld_start.S,v 1.4 2001/09/26 04:06:43 mycroft Exp $ */ 2107572Sgrehan 3107572Sgrehan/*- 4107572Sgrehan * Copyright (C) 1998 Tsubai Masanari 5107572Sgrehan * All rights reserved. 6107572Sgrehan * 7107572Sgrehan * Redistribution and use in source and binary forms, with or without 8107572Sgrehan * modification, are permitted provided that the following conditions 9107572Sgrehan * are met: 10107572Sgrehan * 1. Redistributions of source code must retain the above copyright 11107572Sgrehan * notice, this list of conditions and the following disclaimer. 12107572Sgrehan * 2. Redistributions in binary form must reproduce the above copyright 13107572Sgrehan * notice, this list of conditions and the following disclaimer in the 14107572Sgrehan * documentation and/or other materials provided with the distribution. 15107572Sgrehan * 3. The name of the author may not be used to endorse or promote products 16107572Sgrehan * derived from this software without specific prior written permission. 17107572Sgrehan * 18107572Sgrehan * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19107572Sgrehan * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20107572Sgrehan * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21107572Sgrehan * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22107572Sgrehan * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23107572Sgrehan * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24107572Sgrehan * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25107572Sgrehan * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26107572Sgrehan * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 27107572Sgrehan * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28107572Sgrehan * 29107572Sgrehan * $FreeBSD$ 30107572Sgrehan */ 31107572Sgrehan 32107572Sgrehan#include <machine/asm.h> 33107572Sgrehan 34107572Sgrehan.extern _GLOBAL_OFFSET_TABLE_ 35107572Sgrehan.extern _DYNAMIC 36115396Skan 37209885Snwhitehorn_ENTRY(_rtld_start) 38216780Snwhitehorn stdu %r1,-144(%r1) /* 16-byte aligned stack for reg saves + 39115396Skan exit_proc & obj _rtld args + 40107572Sgrehan backchain & lrsave stack frame */ 41216780Snwhitehorn std %r3,96(%r1) /* argc */ 42216780Snwhitehorn std %r4,104(%r1) /* argv */ 43216780Snwhitehorn std %r5,112(%r1) /* envp */ 44216780Snwhitehorn/* std %r6,120(%r1) *//* obj (always 0) */ 45216780Snwhitehorn/* std %r7,128(%r1) *//* cleanup (always 0) */ 46216780Snwhitehorn std %r8,136(%r1) /* ps_strings */ 47107572Sgrehan 48107572Sgrehan /* 49107572Sgrehan * Perform initial relocation of ld-elf.so. Not as easy as it 50107572Sgrehan * sounds. 51107572Sgrehan * - perform small forward branch to put PC into link reg 52107572Sgrehan * - use link-time constants to determine offset to the 53107572Sgrehan * _DYNAMIC section and the GOT. Add these to the PC to 54107572Sgrehan * convert to absolute addresses. 55107572Sgrehan * - call reloc_non_plt_self() to fix up ld-elf.so's relocations 56107572Sgrehan */ 57209885Snwhitehorn 58107572Sgrehan bl 1f 59209885Snwhitehorn .llong _DYNAMIC-. 60107572Sgrehan1: 61209885Snwhitehorn mflr %r3 /* PC value at .llong */ 62209885Snwhitehorn ld %r4,0(%r3) /* offset to _DYNAMIC */ 63107572Sgrehan add %r3,%r4,%r3 /* r3 = &_DYNAMIC, absolute value */ 64107572Sgrehan 65209885Snwhitehorn ld %r4,-0x8000(%r2) /* First TOC entry is TOC base */ 66209885Snwhitehorn subf %r4,%r4,%r2 /* Subtract from real TOC base to get base */ 67115396Skan 68218824Snwhitehorn bl reloc_non_plt_self /* reloc_non_plt_self(&_DYNAMIC,base) */ 69209885Snwhitehorn nop 70107572Sgrehan 71107572Sgrehan /* 72107572Sgrehan * The _rtld() function likes to see a stack layout containing 73107572Sgrehan * { argc, argv[0], argv[1] ... argv[N], 0, env[0], ... , env[N] } 74107572Sgrehan * Since the PowerPC stack was 16-byte aligned at exec time, the 75107572Sgrehan * original stack layout has to be found by moving back a word 76107572Sgrehan * from the argv pointer. 77107572Sgrehan */ 78216780Snwhitehorn ld %r4,104(%r1) 79209885Snwhitehorn addi %r3,%r4,-8 /* locate argc ptr, &argv[-1] */ 80216780Snwhitehorn addi %r4,%r1,128 /* &exit_proc on stack */ 81216780Snwhitehorn addi %r5,%r1,120 /* &obj_main on stack */ 82107572Sgrehan 83218824Snwhitehorn bl _rtld /* &_start = _rtld(sp, &exit_proc, &obj_main)*/ 84209885Snwhitehorn nop 85209885Snwhitehorn ld %r2,8(%r3) 86209885Snwhitehorn ld %r11,16(%r3) 87209885Snwhitehorn ld %r3,0(%r3) 88107572Sgrehan mtlr %r3 89107572Sgrehan 90107572Sgrehan /* 91107572Sgrehan * Restore args, with new obj/exit proc 92107572Sgrehan */ 93216780Snwhitehorn ld %r3,96(%r1) /* argc */ 94216780Snwhitehorn ld %r4,104(%r1) /* argv */ 95216780Snwhitehorn ld %r5,112(%r1) /* envp */ 96216780Snwhitehorn ld %r6,120(%r1) /* obj */ 97216780Snwhitehorn ld %r7,128(%r1) /* exit proc */ 98216780Snwhitehorn ld %r8,136(%r1) /* ps_strings */ 99107572Sgrehan 100107572Sgrehan blrl /* _start(argc, argv, envp, obj, cleanup, ps_strings) */ 101107572Sgrehan 102107572Sgrehan li %r0,1 /* _exit() */ 103107572Sgrehan sc 104107572Sgrehan 105107572Sgrehan/* 106107572Sgrehan * _rtld_bind_start() 107107572Sgrehan * 108209885Snwhitehorn * Call into the MI binder. This routine is reached via the PLT call cell 109209885Snwhitehorn * On entry, %r11 contains a pointer to the (object, relocation) tuple. 110209885Snwhitehorn * 111209885Snwhitehorn * Save all registers, call into the binder to resolve and fixup the external 112107572Sgrehan * routine, and then transfer to the external routine on return. 113107572Sgrehan */ 114107572Sgrehan .globl _rtld_bind 115107572Sgrehan 116107572Sgrehan_ENTRY(_rtld_bind_start) 117107572Sgrehan mflr %r0 118209885Snwhitehorn std %r0,16(%r1) # save lr 119107572Sgrehan mfcr %r0 120209885Snwhitehorn std %r0,8(%r1) # save cr 121107572Sgrehan 122216780Snwhitehorn stdu %r1,-48-12*8(%r1) # stack space for 8 regs + header 123216780Snwhitehorn # + 2 save regs 124216780Snwhitehorn std %r3,64+0*8(%r1) # save r3-r31 125216780Snwhitehorn std %r4,64+1*8(%r1) 126216780Snwhitehorn std %r5,64+2*8(%r1) 127216780Snwhitehorn std %r6,64+3*8(%r1) 128216780Snwhitehorn std %r7,64+4*8(%r1) 129216780Snwhitehorn std %r8,64+5*8(%r1) 130216780Snwhitehorn std %r9,64+6*8(%r1) 131216780Snwhitehorn std %r10,64+7*8(%r1) 132216780Snwhitehorn std %r12,64+8*8(%r1) 133209885Snwhitehorn 134209885Snwhitehorn ld %r3,0(%r11) 135209885Snwhitehorn ld %r4,8(%r11) 136218824Snwhitehorn bl _rtld_bind # target addr = _rtld_bind(obj, reloff) 137209885Snwhitehorn nop 138209885Snwhitehorn 139209885Snwhitehorn ld %r2,8(%r3) 140209885Snwhitehorn ld %r11,16(%r3) 141209885Snwhitehorn ld %r3,0(%r3) 142107572Sgrehan mtctr %r3 # move absolute target addr into ctr 143107572Sgrehan 144216780Snwhitehorn ld %r3,64+0*8(%r1) # restore r3-r31 145216780Snwhitehorn ld %r4,64+1*8(%r1) 146216780Snwhitehorn ld %r5,64+2*8(%r1) 147216780Snwhitehorn ld %r6,64+3*8(%r1) 148216780Snwhitehorn ld %r7,64+4*8(%r1) 149216780Snwhitehorn ld %r8,64+5*8(%r1) 150216780Snwhitehorn ld %r9,64+6*8(%r1) 151216780Snwhitehorn ld %r10,64+7*8(%r1) 152216780Snwhitehorn ld %r12,64+8*8(%r1) 153209885Snwhitehorn 154216780Snwhitehorn ld %r1,0(%r1) # restore stack 155216780Snwhitehorn ld %r0,8(%r1) # restore cr 156216780Snwhitehorn mtcr %r0 157216780Snwhitehorn ld %r0,16(%r1) # restore lr 158216780Snwhitehorn mtlr %r0 159209885Snwhitehorn 160216780Snwhitehorn bctr # jump to target 161107572Sgrehan 162217397Skib .section .note.GNU-stack,"",%progbits 163