1/* THREAD_* accessors. x86_64 version.
2 Copyright (C) 2002-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19/* Read member of the thread descriptor directly. */
20# define THREAD_GETMEM(descr, member) \
21 ({ __typeof (descr->member) __value; \
22 _Static_assert (sizeof (__value) == 1 \
23 || sizeof (__value) == 4 \
24 || sizeof (__value) == 8, \
25 "size of per-thread data"); \
26 if (sizeof (__value) == 1) \
27 asm volatile ("movb %%fs:%P2,%b0" \
28 : "=q" (__value) \
29 : "0" (0), "i" (offsetof (struct pthread, member))); \
30 else if (sizeof (__value) == 4) \
31 asm volatile ("movl %%fs:%P1,%0" \
32 : "=r" (__value) \
33 : "i" (offsetof (struct pthread, member))); \
34 else /* 8 */ \
35 { \
36 asm volatile ("movq %%fs:%P1,%q0" \
37 : "=r" (__value) \
38 : "i" (offsetof (struct pthread, member))); \
39 } \
40 __value; })
41
42/* THREAD_GETMEM already forces a read. */
43#define THREAD_GETMEM_VOLATILE(descr, member) THREAD_GETMEM (descr, member)
44
45/* Same as THREAD_GETMEM, but the member offset can be non-constant. */
46# define THREAD_GETMEM_NC(descr, member, idx) \
47 ({ __typeof (descr->member[0]) __value; \
48 _Static_assert (sizeof (__value) == 1 \
49 || sizeof (__value) == 4 \
50 || sizeof (__value) == 8, \
51 "size of per-thread data"); \
52 if (sizeof (__value) == 1) \
53 asm volatile ("movb %%fs:%P2(%q3),%b0" \
54 : "=q" (__value) \
55 : "0" (0), "i" (offsetof (struct pthread, member[0])), \
56 "r" (idx)); \
57 else if (sizeof (__value) == 4) \
58 asm volatile ("movl %%fs:%P1(,%q2,4),%0" \
59 : "=r" (__value) \
60 : "i" (offsetof (struct pthread, member[0])), "r" (idx));\
61 else /* 8 */ \
62 { \
63 asm volatile ("movq %%fs:%P1(,%q2,8),%q0" \
64 : "=r" (__value) \
65 : "i" (offsetof (struct pthread, member[0])), \
66 "r" (idx)); \
67 } \
68 __value; })
69
70
71/* Loading addresses of objects on x86-64 needs to be treated special
72 when generating PIC code. */
73#ifdef __pic__
74# define IMM_MODE "nr"
75#else
76# define IMM_MODE "ir"
77#endif
78
79
80/* Set member of the thread descriptor directly. */
81# define THREAD_SETMEM(descr, member, value) \
82 ({ \
83 _Static_assert (sizeof (descr->member) == 1 \
84 || sizeof (descr->member) == 4 \
85 || sizeof (descr->member) == 8, \
86 "size of per-thread data"); \
87 if (sizeof (descr->member) == 1) \
88 asm volatile ("movb %b0,%%fs:%P1" : \
89 : "iq" (value), \
90 "i" (offsetof (struct pthread, member))); \
91 else if (sizeof (descr->member) == 4) \
92 asm volatile ("movl %0,%%fs:%P1" : \
93 : IMM_MODE (value), \
94 "i" (offsetof (struct pthread, member))); \
95 else /* 8 */ \
96 { \
97 /* Since movq takes a signed 32-bit immediate or a register source \
98 operand, use "er" constraint for 32-bit signed integer constant \
99 or register. */ \
100 asm volatile ("movq %q0,%%fs:%P1" : \
101 : "er" ((uint64_t) cast_to_integer (value)), \
102 "i" (offsetof (struct pthread, member))); \
103 }})
104
105
106/* Same as THREAD_SETMEM, but the member offset can be non-constant. */
107# define THREAD_SETMEM_NC(descr, member, idx, value) \
108 ({ \
109 _Static_assert (sizeof (descr->member[0]) == 1 \
110 || sizeof (descr->member[0]) == 4 \
111 || sizeof (descr->member[0]) == 8, \
112 "size of per-thread data"); \
113 if (sizeof (descr->member[0]) == 1) \
114 asm volatile ("movb %b0,%%fs:%P1(%q2)" : \
115 : "iq" (value), \
116 "i" (offsetof (struct pthread, member[0])), \
117 "r" (idx)); \
118 else if (sizeof (descr->member[0]) == 4) \
119 asm volatile ("movl %0,%%fs:%P1(,%q2,4)" : \
120 : IMM_MODE (value), \
121 "i" (offsetof (struct pthread, member[0])), \
122 "r" (idx)); \
123 else /* 8 */ \
124 { \
125 /* Since movq takes a signed 32-bit immediate or a register source \
126 operand, use "er" constraint for 32-bit signed integer constant \
127 or register. */ \
128 asm volatile ("movq %q0,%%fs:%P1(,%q2,8)" : \
129 : "er" ((uint64_t) cast_to_integer (value)), \
130 "i" (offsetof (struct pthread, member[0])), \
131 "r" (idx)); \
132 }})
133

source code of glibc/sysdeps/x86_64/nptl/tcb-access.h