1/* $NetBSD: rtld_start.S,v 1.8 2010/12/05 00:56:07 joerg Exp $ */ 2 3/* 4 * Copyright (c) 2001 Wasabi Systems, Inc. 5 * All rights reserved. 6 * 7 * Written by Frank van der Linden for Wasabi Systems, Inc. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed for the NetBSD Project by 20 * Wasabi Systems, Inc. 21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse 22 * or promote products derived from this software without specific prior 23 * written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC 29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 * POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38#include <machine/asm.h> 39 40 .text 41 .align 16 42 .globl .rtld_start 43 .hidden .rtld_start 44 .type .rtld_start,@function 45.rtld_start: 46 subq $16,%rsp # make room of obj_main and exit proc 47 movq %rsp,%r12 # stack pointer arg to _rtld 48 pushq %rbx # save ps_strings 49 50 andq $~15,%rsp # align rsp, to be restored from r12 51 52 leaq _GLOBAL_OFFSET_TABLE_(%rip),%rax 53 leaq _DYNAMIC(%rip),%rdi # &_DYNAMIC 54 movq %rdi,%rbx 55 subq (%rax),%rbx # relocbase 56 57 movq %rbx,%rsi 58 call _rtld_relocate_nonplt_self 59 60 movq %r12,%rdi 61 movq %rbx,%rsi 62 call _rtld # _rtld(sp, relocbase) 63 64 leaq -8(%r12),%rsp # restore saved rsp, including %rbx 65 popq %rbx # %rbx = ps_strings 66 popq %rdx # %rdx = cleanup 67 popq %rcx # %rcx = obj_main 68 jmp *%rax 69 70 .align 4 71 .globl _rtld_bind_start 72 .hidden _rtld_bind_start 73 .type _rtld_bind_start,@function 74_rtld_bind_start: # (obj, reloff) 75 # This function is called with a misaligned stack from the PLT 76 # due to the additional argument pushed. 77 # At this point %rsp % 16 == 8. 78 pushfq # save caller-saved registers 79 pushq %rax 80 pushq %rcx 81 pushq %rdx 82 pushq %rsi 83 pushq %rdi 84 pushq %r8 85 pushq %r9 86 pushq %r10 87 pushq %r11 88 89 movq 80(%rsp),%rdi 90 movq 88(%rsp),%rsi 91 92 call _rtld_bind # call the binder 93 movq %rax,88(%rsp) # store function in obj 94 95 popq %r11 96 popq %r10 97 popq %r9 98 popq %r8 99 popq %rdi 100 popq %rsi 101 popq %rdx 102 popq %rcx 103 popq %rax 104 popfq 105 106 leaq 8(%rsp),%rsp 107 108 ret 109