2 * Copyright (c) 2014 The FreeBSD Foundation
5 * This software was developed by Andrew Turner under
6 * sponsorship from the FreeBSD Foundation.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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.
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
30 #include <machine/asm.h>
31 __FBSDID("$FreeBSD$");
34 mov x19, x0 /* Put ps_strings in a callee-saved register */
35 mov x20, sp /* And the stack pointer */
37 sub sp, sp, #16 /* Make room for obj_main & exit proc */
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 */
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 */
52 * sp + 0 = &GOT[x + 3]
55 * x17 = &_rtld_bind_start
57 ENTRY(_rtld_bind_start)
60 /* Save frame pointer and SP */
61 stp x29, x30, [sp, #-16]!
67 /* Save the arguments */
68 stp x0, x1, [sp, #-16]!
69 stp x2, x3, [sp, #-16]!
70 stp x4, x5, [sp, #-16]!
71 stp x6, x7, [sp, #-16]!
72 stp x8, xzr, [sp, #-16]!
74 /* Save any floating-point arguments */
75 stp q0, q1, [sp, #-32]!
76 stp q2, q3, [sp, #-32]!
77 stp q4, q5, [sp, #-32]!
78 stp q6, q7, [sp, #-32]!
80 /* Calculate reloff */
81 ldr x2, [x17, #0] /* Get the address of the entry */
82 sub x1, x2, x16 /* Find its offset */
83 sub x1, x1, #8 /* Adjust for x16 not being at offset 0 */
84 /* Each rela item has 3 entriesso we need reloff = 3 * index */
85 lsl x3, x1, #1 /* x3 = 2 * offset */
86 add x1, x1, x3 /* x1 = x3 + offset = 3 * offset */
94 /* Backup the address to branch to */
97 /* restore the arguments */
100 ldp q2, q3, [sp], #32
101 ldp q0, q1, [sp], #32
102 ldp x8, xzr, [sp], #16
103 ldp x6, x7, [sp], #16
104 ldp x4, x5, [sp], #16
105 ldp x2, x3, [sp], #16
106 ldp x0, x1, [sp], #16
108 /* Restore frame pointer */
109 ldp x29, xzr, [sp], #16
111 /* Restore link register saved by the plt code */
112 ldp xzr, x30, [sp], #16
114 /* Call into the correct function */
116 END(_rtld_bind_start)
119 * struct rel_tlsdesc {
120 * uint64_t resolver_fnc;
121 * uint64_t resolver_arg;
124 * uint64_t _rtld_tlsdesc_static(struct rel_tlsdesc *);
126 * Resolver function for TLS symbols resolved at load time
128 ENTRY(_rtld_tlsdesc_static)
131 END(_rtld_tlsdesc_static)
134 * uint64_t _rtld_tlsdesc_undef(void);
136 * Resolver function for weak and undefined TLS symbols
138 ENTRY(_rtld_tlsdesc_undef)
140 .cfi_adjust_cfa_offset 16
147 .cfi_adjust_cfa_offset -16
149 END(_rtld_tlsdesc_undef)
152 * uint64_t _rtld_tlsdesc_dynamic(struct rel_tlsdesc *);
154 * Resolver function for TLS symbols from dlopen()
156 ENTRY(_rtld_tlsdesc_dynamic)
157 /* Save registers used in fast path */
158 stp x1, x2, [sp, #(-2 * 16)]!
159 stp x3, x4, [sp, #(1 * 16)]
160 .cfi_adjust_cfa_offset 2 * 16
161 .cfi_rel_offset x1, 0
162 .cfi_rel_offset x2, 8
163 .cfi_rel_offset x3, 16
164 .cfi_rel_offset x4, 24
166 /* Test fastpath - inlined version of tls_get_addr_common(). */
167 ldr x1, [x0, #8] /* tlsdesc ptr */
169 ldr x0, [x4] /* DTV pointer */
170 ldr x2, [x0] /* dtv[0] (generation count) */
171 ldr x3, [x1] /* tlsdec->dtv_gen */
173 b.ne 1f /* dtv[0] != tlsdec->dtv_gen */
175 ldr w2, [x1, #8] /* tlsdec->tls_index */
177 ldr x3, [x0, w2, sxtw #3] /* dtv[tlsdesc->tls_index + 1] */
180 /* Return (dtv[tlsdesc->tls_index + 1] + tlsdesc->tls_offs - tp) */
181 ldr x2, [x1, #16] /* tlsdec->tls_offs */
184 /* Restore registers and return */
185 ldp x3, x4, [sp, #(1 * 16)]
186 ldp x1, x2, [sp], #(2 * 16)
187 .cfi_adjust_cfa_offset -2 * 16
193 * tls_get_addr_common(tp, tlsdesc->tls_index, tlsdesc->tls_offs));
197 /* Save all interger registers */
198 stp x29, x30, [sp, #-(8 * 16)]!
199 .cfi_adjust_cfa_offset 8 * 16
200 .cfi_rel_offset x29, 0
201 .cfi_rel_offset x30, 8
204 stp x5, x6, [sp, #(1 * 16)]
205 stp x7, x8, [sp, #(2 * 16)]
206 stp x9, x10, [sp, #(3 * 16)]
207 stp x11, x12, [sp, #(4 * 16)]
208 stp x13, x14, [sp, #(5 * 16)]
209 stp x15, x16, [sp, #(6 * 16)]
210 stp x17, x18, [sp, #(7 * 16)]
211 .cfi_rel_offset x5, 16
212 .cfi_rel_offset x6, 24
213 .cfi_rel_offset x7, 32
214 .cfi_rel_offset x8, 40
215 .cfi_rel_offset x9, 48
216 .cfi_rel_offset x10, 56
217 .cfi_rel_offset x11, 64
218 .cfi_rel_offset x12, 72
219 .cfi_rel_offset x13, 80
220 .cfi_rel_offset x14, 88
221 .cfi_rel_offset x15, 96
222 .cfi_rel_offset x16, 104
223 .cfi_rel_offset x17, 112
224 .cfi_rel_offset x18, 120
226 /* Find the tls offset */
228 mov x3, x1 /* tlsdesc ptr */
229 ldr w1, [x3, #8] /* tlsdec->tls_index */
230 ldr x2, [x3, #16] /* tlsdec->tls_offs */
231 bl tls_get_addr_common
235 /* Restore slow patch registers */
236 ldp x17, x18, [sp, #(7 * 16)]
237 ldp x15, x16, [sp, #(6 * 16)]
238 ldp x13, x14, [sp, #(5 * 16)]
239 ldp x11, x12, [sp, #(4 * 16)]
240 ldp x9, x10, [sp, #(3 * 16)]
241 ldp x7, x8, [sp, #(2 * 16)]
242 ldp x5, x6, [sp, #(1 * 16)]
243 ldp x29, x30, [sp], #(8 * 16)
244 .cfi_adjust_cfa_offset -8 * 16
248 /* Restore fast path registers and return */
249 ldp x3, x4, [sp, #16]
250 ldp x1, x2, [sp], #(2 * 16)
251 .cfi_adjust_cfa_offset -2 * 16
253 END(_rtld_tlsdesc_dynamic)