rtld_start.S revision 1.17
1 /* $NetBSD: rtld_start.S,v 1.17 2014/03/18 23:43:38 matt Exp $ */ 2 3 /* 4 * Copyright 1996 Matt Thomas <matt (at) 3am-software.com> 5 * Portions copyright 2002, 2003 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 OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #include <machine/asm.h> 32 33 /* R9 contains the address of PS_STRINGS and since its caller saved, 34 * we can just use it. R6 has a backup copy of the stack pointer which 35 * we can use as well. 36 */ 37 ENTRY(_rtld_start, 0) 38 /* Allocate space on the stack for the cleanup and obj_main 39 * entries that _rtld() will provide for us. 40 */ 41 clrl %fp 42 subl2 $8,%sp 43 44 movab _DYNAMIC,%r0 45 subl3 _GLOBAL_OFFSET_TABLE_,%r0,%r10 46 pushl %r10 /* relocbase */ 47 pushl %r0 /* &_DYNAMIC */ 48 calls $2,_rtld_relocate_nonplt_self 49 50 pushl %r10 /* relocbase */ 51 pushal 4(%sp) /* sp */ 52 calls $2,_rtld /* entry = _rtld(sp, relocbase) */ 53 54 movq (%sp)+,%r7 /* grab cleanup and obj_main into %r7/%r8 */ 55 jmp 2(%r0) /* jump to entry point + 2 */ 56 END(_rtld_start) 57 58 /* 59 * Lazy binding entry point, called via PLT via JMP into pltgot[1]. 60 * SP+0: obj entry points 61 * SP+4: address to relocation index 62 * 63 * Note: Some functions rely on there not being an additional call frame; 64 * hence the `optimization' to avoid the callg opportunistically. 65 */ 66 ALTENTRY(_rtld_bind_start) 67 .cfi_startproc 68 .cfi_def_cfa 13, 60 69 .cfi_offset 16, -56 70 .cfi_offset 12, -52 71 .cfi_offset 13, -48 72 .cfi_offset 15, -44 73 .cfi_offset 2, -40 74 .cfi_offset 3, -36 75 .cfi_offset 4, -32 76 .cfi_offset 5, -28 77 .cfi_offset 6, -24 78 .cfi_offset 7, -20 79 .cfi_offset 8, -16 80 .cfi_offset 9, -12 81 .cfi_offset 10, -8 82 .cfi_offset 11, -4 83 pushr $0x3f /* save R0-R5 */ 84 movq 24(%sp),%r0 /* get addresses of plt.got & reloc index */ 85 pushl (%r1) /* push relocation index */ 86 pushl %r0 /* push address of obj entry */ 87 calls $2,_rtld_bind 88 movl %r0,28(%sp) /* save return address onto stack */ 89 popr $0x3f /* restore R0-R5 (cond flags not modified) */ 90 addl2 $4,%sp 91 callg (%ap),*(%sp)+ /* return value from _rtld_bind() == actual */ 92 ret 93 .cfi_endproc 94 END(_rtld_bind_start) 95
Indexes created Tue Sep 30 20:09:53 GMT 2025