Annotation of src/include/tib.h, Revision 1.3
1.3 ! guenther 1: /* $OpenBSD: tib.h,v 1.2 2016/03/20 02:30:28 guenther Exp $ */
1.1 guenther 2: /*
3: * Copyright (c) 2011,2014 Philip Guenther <guenther@openbsd.org>
4: *
5: * Permission to use, copy, modify, and distribute this software for any
6: * purpose with or without fee is hereby granted, provided that the above
7: * copyright notice and this permission notice appear in all copies.
8: *
9: * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10: * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11: * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12: * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13: * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14: * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15: * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16: */
17:
18: /*
19: * Thread Information Block (TIB) and Thread Local Storage (TLS) handling
20: * (the TCB, Thread Control Block, is part of the TIB)
21: */
22:
23: #ifndef _TIB_H_
24: #define _TIB_H_
25:
26: #include <sys/types.h>
27: #include <machine/tcb.h>
28:
29: #include <stddef.h>
30:
31:
32: /*
33: * This header defines struct tib and at least eight macros:
34: * TLS_VARIANT
35: * Either 1 or 2 (Actually defined by <machine/tcb.h>)
36: *
37: * TCB_SET(tcb)
38: * Set the TCB pointer for this thread to 'tcb'
39: *
40: * TCB_GET()
41: * Return the TCB pointer for this thread
42: *
43: * TCB_TO_TIB(tcb)
44: * Given a TCB pointer, return the matching TIB pointer
45: *
46: * TIB_TO_TCB(tib)
47: * Given a TIB pointer, return the matching TCB pointer
48: *
1.3 ! guenther 49: * TIB_INIT(tib, dtv, thread)
1.1 guenther 50: * Initializes a TIB for a new thread, using the supplied
1.3 ! guenther 51: * values for its dtv and thread pointers
1.1 guenther 52: *
53: * TIB_GET()
54: * Short-hand for TCB_TO_TIB(TCB_GET())
55: *
56: * TIB_EXTRA_ALIGN
57: * On TLS varaint 2 archs, what alignment is sufficient
58: * for the extra space that will be used for struct pthread?
59: *
60: * The following functions are provided by either ld.so (dynamic) or
61: * libc (static) for allocating and freeing a common memory block that
62: * will hold both the TIB and the pthread structure:
1.3 ! guenther 63: * _dl_allocate_tib(sizeof(struct pthread))
1.1 guenther 64: * Allocates a combined TIB and pthread memory region.
1.3 ! guenther 65: * The argument is the amount of space to reserve
! 66: * for the pthread structure. Returns a pointer to
! 67: * the TIB inside the allocated block.
1.1 guenther 68: *
69: * _dl_free_tib(tib, sizeof(struct pthread))
70: * Frees a TIB and pthread block previously allocated
1.3 ! guenther 71: * with _dl_allocate_tib(). Must be passed the return
1.1 guenther 72: * value of that previous call.
73: */
74:
75: /*
76: * Regarding <machine/tcb.h>:
77: * - it must define the TLS_VARIANT macro
1.3 ! guenther 78: * - it may define TCB_OFFSET if the TCB address in the kernel and/or
! 79: * register is offset from the actual TCB address. TCB_OFFSET > 0
! 80: * means the kernel/register points to *after* the real data.
1.1 guenther 81: * - if there's a faster way to get or set the TCB pointer for the thread
82: * than the __{get,set}_tcb() syscalls, it should define either or both
83: * the TCB_{GET,SET} macros to do so.
84: */
85:
86:
87: /* If <machine/tcb.h> doesn't provide a better way, then use the default */
1.2 guenther 88: #ifdef TCB_GET
89: # define TCB_HAVE_MD_GET 1
90: #else
91: # define TCB_GET() __get_tcb()
1.1 guenther 92: #endif
1.2 guenther 93: #ifdef TCB_SET
94: # define TCB_HAVE_MD_SET 1
95: #else
96: # define TCB_SET(tcb) __set_tcb(tcb)
1.1 guenther 97: #endif
1.3 ! guenther 98: #ifndef TCB_OFFSET
! 99: # define TCB_OFFSET 0
! 100: #endif
! 101:
! 102: /*
! 103: * tib_cantcancel values is non-zero is the thread should skip all
! 104: * cancellation processing
! 105: */
! 106: #define CANCEL_DISABLED 1
! 107: #define CANCEL_DYING 2
! 108:
! 109: /*
! 110: * tib_cancel_point is non-zero if we're in a cancel point; its modified
! 111: * by the cancel point code and read by the cancellation signal handler
! 112: */
! 113: #define CANCEL_POINT 1
! 114: #define CANCEL_POINT_DELAYED 2
1.1 guenther 115:
116:
117: #if TLS_VARIANT == 1
118: /*
119: * ABI specifies that the static TLS data starts two words after the
120: * (notional) thread pointer, with the first of those two words being
121: * the TLS dtv pointer. The other (second) word is reserved for the
1.3 ! guenther 122: * implementation, so we place the pointer to the thread structure there,
! 123: * but we place our actual thread bits before the TCB, at negative offsets
! 124: * from the TCB pointer. Ergo, memory is laid out, low to high, as:
1.1 guenther 125: *
1.2 guenther 126: * [pthread structure]
1.1 guenther 127: * TIB {
1.3 ! guenther 128: * ...cancelation and other int-sized info...
1.1 guenther 129: * int errno
1.2 guenther 130: * void *locale
1.3 ! guenther 131: * TCB (- TCB_OFFSET) {
1.1 guenther 132: * void *dtv
1.2 guenther 133: * struct pthread *thread
1.1 guenther 134: * }
135: * }
136: * static TLS data
137: */
138:
139: struct tib {
1.3 ! guenther 140: int tib_thread_flags; /* internal to libpthread */
! 141: pid_t tib_tid;
! 142: int tib_cantcancel;
! 143: int tib_cancel_point;
! 144: int tib_canceled;
1.1 guenther 145: int tib_errno;
1.2 guenther 146: void *tib_locale;
1.1 guenther 147: void *tib_dtv; /* internal to the runtime linker */
1.2 guenther 148: void *tib_thread;
1.1 guenther 149: };
150:
151:
152: #elif TLS_VARIANT == 2
153: /*
154: * ABI specifies that the static TLS data occupies the memory before
155: * the TCB pointer, at negative offsets, and that on i386 and amd64
156: * the word the TCB points to contains a pointer to itself. So,
157: * we place errno and our thread bits after that. Memory is laid
158: * out, low to high, as:
159: * static TLS data
160: * TIB {
1.3 ! guenther 161: * TCB (- TCB_OFFSET) {
1.1 guenther 162: * self pointer [i386/amd64 only]
163: * void *dtv
164: * }
1.2 guenther 165: * struct pthread *thread
1.1 guenther 166: * void *locale
167: * int errno
1.3 ! guenther 168: * ...cancelation and other int-sized info...
1.1 guenther 169: * }
1.2 guenther 170: * [pthread structure]
1.1 guenther 171: */
172:
173: struct tib {
174: #if defined(__i386) || defined(__amd64)
175: struct tib *__tib_self;
1.2 guenther 176: # define __tib_tcb __tib_self
1.1 guenther 177: #endif
178: void *tib_dtv; /* internal to the runtime linker */
1.2 guenther 179: void *tib_thread;
1.1 guenther 180: void *tib_locale;
181: int tib_errno;
1.3 ! guenther 182: int tib_canceled;
! 183: int tib_cancel_point;
! 184: int tib_cantcancel;
! 185: pid_t tib_tid;
! 186: int tib_thread_flags; /* internal to libpthread */
! 187: #if !defined(__LP64__) && !defined(__i386)
1.1 guenther 188: int __tib_padding; /* padding for 8byte alignment */
189: #endif
190: };
191:
1.2 guenther 192: #if defined(__i386) || defined(__amd64)
193: # define _TIB_PREP(tib) \
1.3 ! guenther 194: ((void)((tib)->__tib_self = (tib)))
! 195: #elif !defined(__LP64__) && !defined(__i386)
1.2 guenther 196: # define _TIB_PREP(tib) ((void)((tib)->__tib_padding = 0))
1.1 guenther 197: #endif
198:
199: #define TIB_EXTRA_ALIGN sizeof(void *)
200:
201: #else
202: # error "unknown TLS variant"
203: #endif
204:
205: /* nothing to do by default */
206: #ifndef _TIB_PREP
1.2 guenther 207: # define _TIB_PREP(tib) ((void)0)
1.1 guenther 208: #endif
209:
1.2 guenther 210: #define TIB_INIT(tib, dtv, thread) do { \
211: (tib)->tib_thread = (thread); \
1.1 guenther 212: (tib)->tib_locale = NULL; \
1.3 ! guenther 213: (tib)->tib_cantcancel = 0; \
! 214: (tib)->tib_cancel_point = 0; \
! 215: (tib)->tib_canceled = 0; \
1.1 guenther 216: (tib)->tib_dtv = (dtv); \
217: (tib)->tib_errno = 0; \
218: _TIB_PREP(tib); \
219: } while (0)
220:
221: #ifndef __tib_tcb
1.2 guenther 222: # define __tib_tcb tib_dtv
1.1 guenther 223: #endif
1.3 ! guenther 224: #define _TIBO_TCB (offsetof(struct tib, __tib_tcb) + TCB_OFFSET)
1.1 guenther 225:
226: #define TCB_TO_TIB(tcb) ((struct tib *)((char *)(tcb) - _TIBO_TCB))
227: #define TIB_TO_TCB(tib) ((char *)(tib) + _TIBO_TCB)
228: #define TIB_GET() TCB_TO_TIB(TCB_GET())
229:
230:
231: __BEGIN_DECLS
1.2 guenther 232: void *_dl_allocate_tib(size_t _extra) __dso_public;
1.1 guenther 233: void _dl_free_tib(void *_tib, size_t _extra) __dso_public;
234:
235: /* The actual syscalls */
236: void *__get_tcb(void);
237: void __set_tcb(void *_tcb);
238: __END_DECLS
239:
240: #endif /* _TIB_H_ */
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