1 /* Machine-dependent pthreads configuration and inline functions.
2 ARM version.
3 Copyright (C) 1997, 1998, 2000, 2002 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5 Contributed by Philip Blundell <philb@gnu.org>.
6
7 The GNU C Library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public License as
9 published by the Free Software Foundation; either version 2.1 of the
10 License, or (at your option) any later version.
11
12 The GNU C Library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
16
17 You should have received a copy of the GNU Lesser General Public
18 License along with the GNU C Library; see the file COPYING.LIB. If
19 not, see <http://www.gnu.org/licenses/>. */
20
21 #ifndef _PT_MACHINE_H
22 #define _PT_MACHINE_H 1
23
24 #include <sys/syscall.h>
25 #include <unistd.h>
26
27 #ifndef PT_EI
28 # define PT_EI __extern_always_inline
29 #endif
30
31 #if __ARM_ARCH >= 7 || defined(__thumb2__)
32 /* Spinlock implementation; required. */
33 PT_EI long int
testandset(int * spinlock)34 testandset (int *spinlock)
35 {
36 unsigned int ret, tmp, val = 1;
37
38 __asm__ __volatile__ (
39 "0: ldrex %0, [%2] \n"
40 " strex %1, %3, [%2] \n"
41 " cmp %1, #0 \n"
42 " bne 0b"
43 : "=&r" (ret), "=&r" (tmp)
44 : "r" (spinlock), "r" (val) : "memory", "cc");
45
46 return ret;
47 }
48
49 #elif defined(__thumb__)
50
51 /* This will not work on ARM1 or ARM2 because SWP is lacking on those
52 machines. Unfortunately we have no way to detect this at compile
53 time; let's hope nobody tries to use one. */
54
55 /* Spinlock implementation; required. */
56 PT_EI long int testandset (int *spinlock);
testandset(int * spinlock)57 PT_EI long int testandset (int *spinlock)
58 {
59 register unsigned int ret;
60 void *pc;
61 __asm__ __volatile__(
62 ".align 0\n"
63 "\tbx pc\n"
64 "\tnop\n"
65 "\t.arm\n"
66 "\tswp %0, %2, [%3]\n"
67 "\torr %1, pc, #1\n"
68 "\tbx %1\n"
69 "\t.force_thumb"
70 : "=r"(ret), "=r"(pc)
71 : "0"(1), "r"(spinlock));
72 return ret;
73 }
74
75 #else /* __thumb__ */
76
77 PT_EI long int testandset (int *spinlock);
testandset(int * spinlock)78 PT_EI long int testandset (int *spinlock)
79 {
80 register unsigned int ret;
81 __asm__ __volatile__("swp %0, %1, [%2]"
82 : "=r"(ret)
83 : "0"(1), "r"(spinlock));
84 return ret;
85 }
86 #endif
87
88 /* Get some notion of the current stack. Need not be exactly the top
89 of the stack, just something somewhere in the current frame. */
90 #define CURRENT_STACK_FRAME stack_pointer
91 register char * stack_pointer __asm__ ("sp");
92
93 #endif /* pt-machine.h */
94