aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/arm/dl-trampoline.S
blob: 3c75be738e78e600e15cf153b886975cd83bb29f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
/* PLT trampolines.  ARM version.
   Copyright (C) 2005-2016 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library.  If not, see
   <http://www.gnu.org/licenses/>.  */

/* ??? Needs more rearrangement for the LDM to handle thumb mode.  */
#define NO_THUMB
#include <sysdep.h>
#include <libc-symbols.h>

	.text
	.globl _dl_runtime_resolve
	.type _dl_runtime_resolve, #function
	CFI_SECTIONS
	cfi_startproc
	.align 2
_dl_runtime_resolve:
	cfi_adjust_cfa_offset (4)
	cfi_rel_offset (lr, 0)

	@ we get called with
	@ 	stack[0] contains the return address from this call
	@	ip contains &GOT[n+3] (pointer to function)
	@	lr points to &GOT[2]

	@ Save arguments.  We save r4 to realign the stack.
	push	{r0-r4}
	cfi_adjust_cfa_offset (20)
	cfi_rel_offset (r0, 0)
	cfi_rel_offset (r1, 4)
	cfi_rel_offset (r2, 8)
	cfi_rel_offset (r3, 12)

	@ get pointer to linker struct
	ldr	r0, [lr, #-4]

	@ prepare to call _dl_fixup()
	@ change &GOT[n+3] into 8*n        NOTE: reloc are 8 bytes each
	sub	r1, ip, lr
	sub	r1, r1, #4
	add	r1, r1, r1

	@ call fixup routine
	bl	_dl_fixup

	@ save the return
	mov	ip, r0

	@ get arguments and return address back.  We restore r4
	@ only to realign the stack.
	pop	{r0-r4,lr}
	cfi_adjust_cfa_offset (-24)

	@ jump to the newly found address
	BX(ip)

	cfi_endproc
	.size _dl_runtime_resolve, .-_dl_runtime_resolve

#ifndef PROF
	.globl _dl_runtime_profile
	.type _dl_runtime_profile, #function
	CFI_SECTIONS
	cfi_startproc
	.align 2
_dl_runtime_profile:
	cfi_adjust_cfa_offset (4)
	cfi_rel_offset (lr, 0)

	@ we get called with
	@ 	stack[0] contains the return address from this call
	@	ip contains &GOT[n+3] (pointer to function)
	@	lr points to &GOT[2]

	@ Stack layout:
	@ 212 - saved lr
	@ 208 - framesize returned from pltenter
	@ 16 - La_arm_regs
	@ 8 - Saved two arguments to _dl_profile_fixup
	@ 4 - Saved result of _dl_profile_fixup
	@ 0 - outgoing argument to _dl_profile_fixup
	@ For now, we only save the general purpose registers.

	sub	sp, sp, #196
	cfi_adjust_cfa_offset (196)
	stmia	sp, {r0-r3}
	cfi_rel_offset (r0, 0)
	cfi_rel_offset (r1, 4)
	cfi_rel_offset (r2, 8)
	cfi_rel_offset (r3, 12)

	sub	sp, sp, #16
	cfi_adjust_cfa_offset (16)

	@ Save sp and lr.
	add	r0, sp, #216
	str	r0, [sp, #32]
	ldr	r2, [sp, #212]
	str	r2, [sp, #36]

	@ get pointer to linker struct
	ldr	r0, [lr, #-4]

	@ prepare to call _dl_profile_fixup()
	@ change &GOT[n+3] into 8*n        NOTE: reloc are 8 bytes each
	sub	r1, ip, lr
	sub	r1, r1, #4
	add	r1, r1, r1

	@ Save these two arguments for pltexit.
	add	r3, sp, #8
	stmia	r3!, {r0,r1}

	@ Set up extra args for _dl_profile_fixup.
	@ r2 and r3 are already loaded.
	add	ip, sp, #208
	str	ip, [sp, #0]

	@ call profiling fixup routine
	bl	_dl_profile_fixup

	@ The address to call is now in r0.

	@ Check whether we're wrapping this function.
	ldr	ip, [sp, #208]
	cmp	ip, #0
	bge	1f
	cfi_remember_state

	@ save the return
	mov	ip, r0

	@ get arguments and return address back
	add	sp, sp, #16
	cfi_adjust_cfa_offset (-16)
	ldmia	sp, {r0-r3,sp,lr}
	cfi_adjust_cfa_offset (-200)

	@ jump to the newly found address
	BX(ip)

	cfi_restore_state
1:
	@ The new frame size is in ip.

	@ New stack layout:
	@ 268 - saved r7
	@ 264 - saved result of _dl_profile_fixup
	@ 72 - La_arm_regs
	@ 64 - Saved two arguments to _dl_profile_fixup
	@ 0 - La_arm_retval
	@ For now, we only save the general purpose registers.

	@ Build the new frame.
	str	r7, [sp, #212]
	cfi_rel_offset (r7, 212)
	sub	r7, sp, #56
	cfi_def_cfa_register (r7)
	cfi_adjust_cfa_offset (56)
	sub	sp, sp, ip
	bic	sp, sp, #7

	@ Save the _dl_profile_fixup result around the call to memcpy.
	str	r0, [r7, #264]

	@ Copy the stack arguments.
	mov	r0, sp
	add	r1, r7, #272
	mov	r2, ip
	bl	memcpy

	@ Call the function.
	add	ip, r7, #72
	ldmia	ip, {r0-r3}
	ldr	ip, [r7, #264]
	BLX(ip)
	stmia	r7, {r0-r3}

	@ Call pltexit.
	add	ip, r7, #64
	ldmia	ip, {r0,r1}
	add	r2, r7, #72
	add	r3, r7, #0
	bl	_dl_call_pltexit

	@ Return to caller.
	ldmia	r7, {r0-r3}
	mov	sp, r7
	cfi_def_cfa_register (sp)
	ldr	r7, [sp, #268]
	ldr	lr, [sp, #92]
	add	sp, sp, #272
	cfi_adjust_cfa_offset (-272)
	BX(lr)

	cfi_endproc
	.size _dl_runtime_profile, .-_dl_runtime_profile
#endif
	.previous