1/* $NetBSD: rtld_start.S,v 1.1 2014/08/10 05:47:37 matt Exp $ */ 2 3/*- 4 * Copyright (c) 2014 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Matt Thomas of 3am Software Foundry. 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 34RCSID("$NetBSD: rtld_start.S,v 1.1 2014/08/10 05:47:37 matt Exp $") 35 36/* 37 * void _rtld_start(void (*cleanup)(void), const Obj_Entry *obj, 38 * struct ps_strings *ps_strings); 39 * 40 * X0 = NULL 41 * X1 = NULL 42 * X2 = ps_strings 43 * X30 (LR) = 0 44 * X29 (FP) = 0 45 */ 46 47ENTRY_NP(_rtld_start) 48 mov x24, x2 /* save ps_strings */ 49 50#if 1 51 adrp x1, _PROCEDURE_LINKAGE_TABLE_ /* load _DYNAMIC offset from GOT */ 52 ldr x1, [x1, #:got_lo12:_PROCEDURE_LINKAGE_TABLE_] 53#else 54 adrp x1, :got:_DYNAMIC /* load _DYNAMIC offset from GOT */ 55 ldr x1, [x1, #:got_lo12:_DYNAMIC] 56#endif 57 58 adrp x0, _DYNAMIC /* get &_DYNAMIC */ 59 add x0, x0, #:lo12:_DYNAMIC 60 sub x25, x0, x1 /* relocbase = &_DYNAMIC - GOT:_DYNAMIC */ 61 mov x1, x25 /* pass as 2nd argument */ 62 bl _rtld_relocate_nonplt_self 63 64 sub sp, sp, #16 /* reserve space for returns */ 65 mov x0, sp /* pointer to reserved space */ 66 mov x1, x25 /* pass relocbase */ 67 bl _rtld 68 mov x17, x0 /* save entry point */ 69 70 ldp x0, x1, [sp], #16 /* pop cleanup & obj_main */ 71 mov x2, x24 /* restore ps_strings */ 72 73 br x17 /* call saved entry point */ 74END(_rtld_start) 75 76/* 77 * Upon entry from plt0 entry: 78 * X17 = &PLTGOT[n] 79 * X16 = &PLTGOT[2] 80 */ 81ENTRY_NP(_rtld_bind_start) 82 sub sp, sp, #96 /* reserve stack space */ 83 stp x29, x30, [sp, #80] /* save FP & LR */ 84 add x29, sp, #80 /* get new FP */ 85 str x24, [sp, #64] /* save caller-saved register */ 86 stp x6, x7, [sp, #48] /* save arguments */ 87 stp x4, x5, [sp, #32] /* save arguments */ 88 stp x2, x3, [sp, #16] /* save arguments */ 89 stp x0, x1, [sp, #0] /* save arguments */ 90 91 sub x16, x16, #16 /* adjust to &PLTGOT[0] */ 92 mov x24, x17 /* preserve across _rtld_bind */ 93 sub x1, x17, x16 /* x1 = &PLTGOT[N] - &PLTGOT[2] */ 94 lsr x1, x1, #3 /* x1 = N - 2 */ 95 ldr x0, [x16, #8] /* get obj ptr from &PLTGOT[1] */ 96 bl _rtld_bind 97 str x0, [x24] /* save address in PLTGOT[N] */ 98 mov x17, x0 /* save address */ 99 100 ldp x0, x1, [sp, #0] /* restore arguments */ 101 ldp x2, x3, [sp, #16] /* restore arguments */ 102 ldp x4, x5, [sp, #32] /* restore arguments */ 103 ldp x6, x7, [sp, #48] /* restore arguments */ 104 ldr x24, [sp, #64] /* save caller-saved register */ 105 ldp x29, x30, [sp, #80] /* restore FP & LR */ 106 add sp, sp, #96 /* reclaim stack */ 107 br x17 /* call bound function */ 108END(_rtld_bind_start) 109