about summary refs log tree commit diff
path: root/sysdeps/tile/dl-trampoline.S
blob: 7669d77b3278459b65fb3fb0664c306750e63b49 (plain) (blame)
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
/* Copyright (C) 2011-2018 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.

   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/>.  */

#include <sysdep.h>
#include <arch/abi.h>

/* This function is called via the PLT header, which is called
   from an individual PLT entry.

   At this point we have several values passed in:

   lr:  return address to original user code
   r28: the tpnt value to pass to _dl_runtime_resolver
   r29: the PLT index of the invoked jump table entry.

   We set up a frame entry that looks like this (in int_reg_t units):

   +57: r25 return values from function...
   +56: r24
   [...]
   +33: r1
   +32: r0
   +31: PLT index
   +30: tpnt
   +29: stackframe
   +28: caller lr
   +27: r25 arguments to function...
   +26: r24
   [...]
   +3:  r1
   +2:  r0
   +1:  standard ABI slot (sp)
   +0:  standard ABI slot (callee lr)

   The entries from "stackframe" up are only used in _dl_profile_resolve.
   We save and restore r0 through r25, rather than the strictly
   architected r0 through r9, to support unusual calling conventions;
   for example, __tls_get_addr takes r0 and returns r0, but promises
   not to clobber r1 through r24 to support its usual fast path.  */

#define FRAME_SP		(1 * REGSIZE)
#define FRAME_REGS		(2 * REGSIZE)
#define FRAME_LR		(28 * REGSIZE)  /* Must follow FRAME_REGS */
#define FRAME_STACKFRAME	(29 * REGSIZE)
#define FRAME_TPNT		(30 * REGSIZE)
#define FRAME_INDEX		(31 * REGSIZE)
#define FRAME_RETVAL		(32 * REGSIZE)

#define FRAME_SIZE_SMALL	(30 * REGSIZE)
#define FRAME_SIZE_LARGE	(58 * REGSIZE)

#define FOR_EACH_REG(f) \
	f(r0);  f(r1);  f(r2);  f(r3);  \
	f(r4);  f(r5);  f(r6);  f(r7);  \
	f(r8);  f(r9);  f(r10); f(r11); \
	f(r12); f(r13); f(r14); f(r15); \
	f(r16); f(r17); f(r18); f(r19); \
	f(r20); f(r21); f(r22); f(r23); \
	f(r24); f(r25)

#define SAVE(REG) { st r27, REG; ADDI_PTR r27, r27, REGSIZE }
#define RESTORE(REG) { ld REG, r27; ADDI_PTR r27, r27, REGSIZE }

	.macro dl_resolve, name, profile, framesize
.text
.global \name
.hidden \name
/* Note that cpp expands ENTRY(\name) incorrectly. */
.type \name,@function
.align 8
\name:
	cfi_startproc
	{
	 st sp, lr
	 move r26, sp
	}
	{
	 ADDLI_PTR sp, sp, -\framesize
	 ADDLI_PTR r27, sp, FRAME_SP - \framesize
	}
	cfi_def_cfa_offset (\framesize)
	{
	 st r27, r26
	 ADDI_PTR r27, r27, FRAME_REGS - FRAME_SP
	}
	FOR_EACH_REG(SAVE)
	{
	 st r27, lr
	 ADDLI_PTR r27, sp, FRAME_TPNT
	}
	cfi_offset (lr, FRAME_LR - \framesize)
	.if \profile
	{
	 move r0, r28  /* tpnt value */
	 st r27, r28
	 ADDI_PTR r27, r27, FRAME_INDEX - FRAME_TPNT
	}
	{
	 move r1, r29  /* PLT index */
	 st r27, r29
	}
	{
	 move r2, lr  /* retaddr */
	 ADDI_PTR r3, sp, FRAME_REGS  /* La_tile_regs pointer */
	}
	{
	 ADDLI_PTR r4, sp, FRAME_STACKFRAME  /* framesize pointer */
	 jal _dl_profile_fixup
	}
	ADDLI_PTR r28, sp, FRAME_STACKFRAME
	LD_PTR r28, r28
	bgtz r28, 1f
	.else
	{
	 move r0, r28  /* tpnt value 1 */
	 move r1, r29  /* PLT index 2 */
	}
	jal _dl_fixup
	.endif
	{
	 /* Copy aside the return value so we can restore r0 below. */
	 move r29, r0
	 /* Set up r27 to let us start restoring registers. */
	 ADDLI_PTR r27, sp, FRAME_REGS
	}
	FOR_EACH_REG(RESTORE)
	.if \profile
	ADDLI_PTR r28, sp, FRAME_STACKFRAME
	ld r28, r28
	bgtz r28, 1f
	.endif
	{
	 /* Restore original user return address. */
	 ld lr, r27
	 /* Pop off our stack frame. */
	 ADDLI_PTR sp, sp, \framesize
	}
	cfi_def_cfa_offset (0)
	jr r29  /* Transfer control to freshly loaded code. */
	jrp lr  /* Keep backtracer happy. */

	.if \profile
1:	jalr r29   /* Call resolved function. */
	{
	 ADDLI_PTR r28, sp, FRAME_TPNT
	 ADDLI_PTR r27, sp, FRAME_RETVAL
	}
	FOR_EACH_REG(SAVE)
	{
	 ld r0, r28
	 ADDI_PTR r28, r28, FRAME_INDEX - FRAME_TPNT
	}
        {
	 ld r1, r28
	 ADDLI_PTR r2, sp, FRAME_REGS
	}
	{
	 ADDLI_PTR r3, sp, FRAME_RETVAL
	 jal _dl_call_pltexit
	}
	{
	 ADDLI_PTR lr, sp, FRAME_LR
	 ADDLI_PTR r27, sp, FRAME_RETVAL
        }
	FOR_EACH_REG(RESTORE)
	{
	 ld lr, lr
	 ADDLI_PTR sp, sp, \framesize
	}
	jrp lr
	.endif
END (\name)
	.endm

	dl_resolve _dl_runtime_resolve, 0, FRAME_SIZE_SMALL
#ifndef PROF
	dl_resolve _dl_runtime_profile, 1, FRAME_SIZE_LARGE
#endif