1/*- 2 * Copyright (c) 2014 The FreeBSD Foundation 3 * All rights reserved. 4 * 5 * This software was developed by Andrew Turner under 6 * sponsorship from the FreeBSD Foundation. 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 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30#include <machine/asm.h> 31__FBSDID("$FreeBSD$"); 32 33ENTRY(.rtld_start) 34 mov x19, x0 /* Put ps_strings in a callee-saved register */ 35 mov x20, sp /* And the stack pointer */ 36 37 sub sp, sp, #16 /* Make room for obj_main & exit proc */ 38 39 mov x1, sp /* exit_proc */ 40 add x2, x1, #8 /* obj_main */ 41 bl _rtld /* Call the loader */ 42 mov x8, x0 /* Backup the entry point */ 43 44 ldr x2, [sp] /* Load cleanup */ 45 ldr x1, [sp, #8] /* Load obj_main */ 46 mov x0, x19 /* Restore ps_strings */ 47 mov sp, x20 /* Restore the stack pointer */ 48 br x8 /* Jump to the entry point */ 49END(.rtld_start) 50 51/* 52 * sp + 0 = &GOT[x + 3] 53 * sp + 8 = RA 54 * x16 = &GOT[2] 55 * x17 = &_rtld_bind_start 56 */ 57ENTRY(_rtld_bind_start) 58 mov x17, sp 59 60 /* Save the arguments */ 61 stp x0, x1, [sp, #-16]! 62 stp x2, x3, [sp, #-16]! 63 stp x4, x5, [sp, #-16]! 64 stp x6, x7, [sp, #-16]! 65 stp x8, xzr, [sp, #-16]! 66 67 /* Save any floating-point arguments */ 68 stp q0, q1, [sp, #-32]! 69 stp q2, q3, [sp, #-32]! 70 stp q4, q5, [sp, #-32]! 71 stp q6, q7, [sp, #-32]! 72 73 /* Calculate reloff */ 74 ldr x2, [x17, #0] /* Get the address of the entry */ 75 sub x1, x2, x16 /* Find its offset */ 76 sub x1, x1, #8 /* Adjust for x16 not being at offset 0 */ 77 /* Each rela item has 3 entriesso we need reloff = 3 * index */ 78 lsl x3, x1, #1 /* x3 = 2 * offset */ 79 add x1, x1, x3 /* x1 = x3 + offset = 3 * offset */ 80 81 /* Load obj */ 82 ldr x0, [x16, #-8] 83 84 /* Call into rtld */ 85 bl _rtld_bind 86 87 /* Restore the registers saved by the plt code */ 88 ldp xzr, x30, [sp, #(5 * 16 + 4 * 32)] 89 90 /* Backup the address to branch to */ 91 mov x16, x0 92 93 /* restore the arguments */ 94 ldp q6, q7, [sp], #32 95 ldp q4, q5, [sp], #32 96 ldp q2, q3, [sp], #32 97 ldp q0, q1, [sp], #32 98 ldp x8, xzr, [sp], #16 99 ldp x6, x7, [sp], #16 100 ldp x4, x5, [sp], #16 101 ldp x2, x3, [sp], #16 102 ldp x0, x1, [sp], #16 103 /* And the part of the stack the plt entry handled */ 104 add sp, sp, #16 105 106 /* Call into the correct function */ 107 br x16 108END(_rtld_bind_start) 109 110/* 111 * uint64_t _rtld_tlsdesc(struct tlsdesc *); 112 * 113 * struct tlsdesc { 114 * uint64_t ptr; 115 * uint64_t data; 116 * }; 117 * 118 * Returns the data. 119 */ 120ENTRY(_rtld_tlsdesc) 121 ldr x0, [x0, #8] 122 ret 123END(_rtld_tlsdesc) 124 125/* 126 * uint64_t _rtld_tlsdesc_dynamic(struct tlsdesc *); 127 * 128 * TODO: We could lookup the saved index here to skip saving the entire stack. 129 */ 130ENTRY(_rtld_tlsdesc_dynamic) 131 /* Store any registers we may use in rtld_tlsdesc_handle */ 132 stp x29, x30, [sp, #-(10 * 16)]! 133 mov x29, sp 134 stp x1, x2, [sp, #(1 * 16)] 135 stp x3, x4, [sp, #(2 * 16)] 136 stp x5, x6, [sp, #(3 * 16)] 137 stp x7, x8, [sp, #(4 * 16)] 138 stp x9, x10, [sp, #(5 * 16)] 139 stp x11, x12, [sp, #(6 * 16)] 140 stp x13, x14, [sp, #(7 * 16)] 141 stp x15, x16, [sp, #(8 * 16)] 142 stp x17, x18, [sp, #(9 * 16)] 143 144 /* Find the tls offset */ 145 ldr x0, [x0, #8] 146 mov x1, #1 147 bl rtld_tlsdesc_handle 148 149 /* Restore the registers */ 150 ldp x17, x18, [sp, #(9 * 16)] 151 ldp x15, x16, [sp, #(8 * 16)] 152 ldp x13, x14, [sp, #(7 * 16)] 153 ldp x11, x12, [sp, #(6 * 16)] 154 ldp x9, x10, [sp, #(5 * 16)] 155 ldp x7, x8, [sp, #(4 * 16)] 156 ldp x5, x6, [sp, #(3 * 16)] 157 ldp x3, x4, [sp, #(2 * 16)] 158 ldp x1, x2, [sp, #(1 * 16)] 159 ldp x29, x30, [sp], #(10 * 16) 160 161 ret 162END(_rtld_tlsdesc_dynamic) 163