about summary refs log tree commit diff
path: root/sysdeps/unix/sysv/linux/arm/sysdep-cancel.h
blob: de12acf046b1cd59ee0853ce4c47c5975ea33de0 (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
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
/* Copyright (C) 2003-2017 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/>.  */

#include <sysdep.h>
#include <tls.h>
#ifndef __ASSEMBLER__
# include <nptl/pthreadP.h>
#endif

#if IS_IN (libc) || IS_IN (libpthread) || IS_IN (librt)

/* NOTE: We do mark syscalls with unwind annotations, for the benefit of
   cancellation; but they're really only accurate at the point of the
   syscall.  The ARM unwind directives are not rich enough without adding
   a custom personality function.  */

# undef PSEUDO
# define PSEUDO(name, syscall_name, args)				\
	.text;								\
  ENTRY (__##syscall_name##_nocancel);					\
	CFI_SECTIONS;							\
	DO_CALL (syscall_name, args);					\
	cmn	r0, $4096;						\
	PSEUDO_RET;							\
  END (__##syscall_name##_nocancel);					\
  ENTRY (name);								\
	SINGLE_THREAD_P;						\
	DOARGS_##args;							\
	bne .Lpseudo_cancel;						\
	cfi_remember_state;						\
	ldr	r7, =SYS_ify (syscall_name);				\
	swi	0x0;							\
	UNDOARGS_##args;						\
	cmn	r0, $4096;						\
	PSEUDO_RET;							\
	cfi_restore_state;						\
  .Lpseudo_cancel:							\
	.fnstart;	/* matched by the .fnend in UNDOARGS below.  */	\
	DOCARGS_##args;	/* save syscall args etc. around CENABLE.  */	\
	CENABLE;							\
	mov ip, r0;		/* put mask in safe place.  */		\
	UNDOCARGS_##args;	/* restore syscall args.  */		\
	ldr	r7, =SYS_ify (syscall_name);				\
	swi	0x0;		/* do the call.  */			\
	mov	r7, r0;		/* save syscall return value.  */	\
	mov	r0, ip;		/* get mask back.  */			\
	CDISABLE;							\
	mov	r0, r7;		/* retrieve return value.  */		\
	RESTORE_LR_##args;						\
	UNDOARGS_##args;						\
	cmn	r0, $4096

/* DOARGS pushes eight bytes on the stack for five arguments, twelve bytes for
   six arguments, and four bytes for fewer.  In order to preserve doubleword
   alignment, sometimes we must save an extra register.  */

# define RESTART_UNWIND				\
	.fnend;					\
	.fnstart;				\
	.save	{r7};				\
	.save	{lr}

# define DOCARGS_0				\
	.save {r7};				\
	push	{lr};				\
	cfi_adjust_cfa_offset (4);		\
	cfi_rel_offset (lr, 0);			\
	.save	{lr}
# define UNDOCARGS_0
# define RESTORE_LR_0				\
	pop	{lr};				\
	cfi_adjust_cfa_offset (-4);		\
	cfi_restore (lr)

# define DOCARGS_1				\
	.save	{r7};				\
	push	{r0, r1, lr};			\
	cfi_adjust_cfa_offset (12);		\
	cfi_rel_offset (lr, 8);			\
	.save	{lr};				\
	.pad	#8
# define UNDOCARGS_1				\
	ldr r0, [sp], #8;			\
	cfi_adjust_cfa_offset (-8);		\
	RESTART_UNWIND
# define RESTORE_LR_1				\
	RESTORE_LR_0

# define DOCARGS_2				\
	.save	{r7};				\
	push	{r0, r1, lr};			\
	cfi_adjust_cfa_offset (12);		\
	cfi_rel_offset (lr, 8);			\
	.save	{lr};				\
	.pad	#8
# define UNDOCARGS_2				\
	pop	{r0, r1};			\
	cfi_adjust_cfa_offset (-8);		\
	RESTART_UNWIND
# define RESTORE_LR_2				\
	RESTORE_LR_0

# define DOCARGS_3				\
	.save	{r7};				\
	push	{r0, r1, r2, r3, lr};		\
	cfi_adjust_cfa_offset (20);		\
	cfi_rel_offset (lr, 16);		\
	.save	{lr};				\
	.pad	#16
# define UNDOCARGS_3				\
	pop	{r0, r1, r2, r3};		\
	cfi_adjust_cfa_offset (-16);		\
	RESTART_UNWIND
# define RESTORE_LR_3				\
	RESTORE_LR_0

# define DOCARGS_4				\
	.save	{r7};				\
	push	{r0, r1, r2, r3, lr};		\
	cfi_adjust_cfa_offset (20);		\
	cfi_rel_offset (lr, 16);		\
	.save	{lr};				\
	.pad	#16
# define UNDOCARGS_4				\
	pop	{r0, r1, r2, r3};		\
	cfi_adjust_cfa_offset (-16);		\
	RESTART_UNWIND
# define RESTORE_LR_4				\
	RESTORE_LR_0

/* r4 is only stmfd'ed for correct stack alignment.  */
# define DOCARGS_5				\
	.save	{r4, r7};			\
	push	{r0, r1, r2, r3, r4, lr};	\
	cfi_adjust_cfa_offset (24);		\
	cfi_rel_offset (lr, 20);		\
	.save	{lr};				\
	.pad	#20
# define UNDOCARGS_5				\
	pop	{r0, r1, r2, r3};		\
	cfi_adjust_cfa_offset (-16);		\
	.fnend;					\
	.fnstart;				\
	.save	{r4, r7};			\
	.save	{lr};				\
	.pad	#4
# define RESTORE_LR_5				\
	pop	{r4, lr};			\
	cfi_adjust_cfa_offset (-8);		\
	/* r4 will be marked as restored later.  */ \
	cfi_restore (lr)

# define DOCARGS_6				\
	.save	{r4, r5, r7};			\
	push	{r0, r1, r2, r3, lr};		\
	cfi_adjust_cfa_offset (20);		\
	cfi_rel_offset (lr, 16);		\
	.save	{lr};				\
	.pad	#16
# define UNDOCARGS_6				\
	pop	{r0, r1, r2, r3};		\
	cfi_adjust_cfa_offset (-16);		\
	.fnend;					\
	.fnstart;				\
	.save	{r4, r5, r7};			\
	.save	{lr};
# define RESTORE_LR_6				\
	RESTORE_LR_0

# if IS_IN (libpthread)
#  define CENABLE	bl PLTJMP(__pthread_enable_asynccancel)
#  define CDISABLE	bl PLTJMP(__pthread_disable_asynccancel)
#  define __local_multiple_threads __pthread_multiple_threads
# elif IS_IN (libc)
#  define CENABLE	bl PLTJMP(__libc_enable_asynccancel)
#  define CDISABLE	bl PLTJMP(__libc_disable_asynccancel)
#  define __local_multiple_threads __libc_multiple_threads
# elif IS_IN (librt)
#  define CENABLE	bl PLTJMP(__librt_enable_asynccancel)
#  define CDISABLE	bl PLTJMP(__librt_disable_asynccancel)
# else
#  error Unsupported library
# endif

# if IS_IN (libpthread) || IS_IN (libc)
#  ifndef __ASSEMBLER__
extern int __local_multiple_threads attribute_hidden;
#   define SINGLE_THREAD_P __builtin_expect (__local_multiple_threads == 0, 1)
#  else
#   define SINGLE_THREAD_P						\
	LDST_PCREL(ldr, ip, ip, __local_multiple_threads);		\
	teq ip, #0
#  endif
# else
/*  There is no __local_multiple_threads for librt, so use the TCB.  */
#  ifndef __ASSEMBLER__
#   define SINGLE_THREAD_P						\
  __builtin_expect (THREAD_GETMEM (THREAD_SELF,				\
				   header.multiple_threads) == 0, 1)
#  else
#   define SINGLE_THREAD_P						\
	push	{r0, lr};						\
	cfi_adjust_cfa_offset (8);					\
	cfi_rel_offset (lr, 4);						\
	GET_TLS (lr);							\
	NEGOFF_ADJ_BASE (r0, MULTIPLE_THREADS_OFFSET);			\
	ldr	ip, NEGOFF_OFF1 (r0, MULTIPLE_THREADS_OFFSET);		\
	pop	{r0, lr};						\
	cfi_adjust_cfa_offset (-8);					\
	cfi_restore (lr);						\
	teq	ip, #0
#  endif
# endif

#elif !defined __ASSEMBLER__

/* For rtld, et cetera.  */
# define SINGLE_THREAD_P 1
# define NO_CANCELLATION 1

#endif

#ifndef __ASSEMBLER__
# define RTLD_SINGLE_THREAD_P \
  __builtin_expect (THREAD_GETMEM (THREAD_SELF, \
				   header.multiple_threads) == 0, 1)
#endif