1 | /* $NetBSD: cdefs_elf.h,v 1.52 2016/06/07 12:09:29 joerg Exp $ */ |
2 | |
3 | /* |
4 | * Copyright (c) 1995, 1996 Carnegie-Mellon University. |
5 | * All rights reserved. |
6 | * |
7 | * Author: Chris G. Demetriou |
8 | * |
9 | * Permission to use, copy, modify and distribute this software and |
10 | * its documentation is hereby granted, provided that both the copyright |
11 | * notice and this permission notice appear in all copies of the |
12 | * software, derivative works or modified versions, and any portions |
13 | * thereof, and that both notices appear in supporting documentation. |
14 | * |
15 | * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" |
16 | * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND |
17 | * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. |
18 | * |
19 | * Carnegie Mellon requests users of this software to return to |
20 | * |
21 | * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU |
22 | * School of Computer Science |
23 | * Carnegie Mellon University |
24 | * Pittsburgh PA 15213-3890 |
25 | * |
26 | * any improvements or extensions that they make and grant Carnegie the |
27 | * rights to redistribute these changes. |
28 | */ |
29 | |
30 | #ifndef _SYS_CDEFS_ELF_H_ |
31 | #define _SYS_CDEFS_ELF_H_ |
32 | |
33 | #ifdef __LEADING_UNDERSCORE |
34 | #define _C_LABEL(x) __CONCAT(_,x) |
35 | #define _C_LABEL_STRING(x) "_"x |
36 | #else |
37 | #define _C_LABEL(x) x |
38 | #define _C_LABEL_STRING(x) x |
39 | #endif |
40 | |
41 | #if __STDC__ |
42 | #define ___RENAME(x) __asm(___STRING(_C_LABEL(x))) |
43 | #else |
44 | #ifdef __LEADING_UNDERSCORE |
45 | #define ___RENAME(x) ____RENAME(_/**/x) |
46 | #define ____RENAME(x) __asm(___STRING(x)) |
47 | #else |
48 | #define ___RENAME(x) __asm(___STRING(x)) |
49 | #endif |
50 | #endif |
51 | |
52 | #define __indr_reference(sym,alias) /* nada, since we do weak refs */ |
53 | |
54 | #if __STDC__ |
55 | #define __strong_alias(alias,sym) \ |
56 | __asm(".global " _C_LABEL_STRING(#alias) "\n" \ |
57 | _C_LABEL_STRING(#alias) " = " _C_LABEL_STRING(#sym)); |
58 | |
59 | #define __weak_alias(alias,sym) \ |
60 | __asm(".weak " _C_LABEL_STRING(#alias) "\n" \ |
61 | _C_LABEL_STRING(#alias) " = " _C_LABEL_STRING(#sym)); |
62 | |
63 | /* Do not use __weak_extern, use __weak_reference instead */ |
64 | #define __weak_extern(sym) \ |
65 | __asm(".weak " _C_LABEL_STRING(#sym)); |
66 | |
67 | #if __GNUC_PREREQ__(4, 0) |
68 | #define __weak __attribute__((__weak__)) |
69 | #else |
70 | #define __weak |
71 | #endif |
72 | |
73 | #if __GNUC_PREREQ__(4, 0) |
74 | #define __weak_reference(sym) __attribute__((__weakref__(#sym))) |
75 | #else |
76 | #define __weak_reference(sym) ; __asm(".weak " _C_LABEL_STRING(#sym)) |
77 | #endif |
78 | |
79 | #if __GNUC_PREREQ__(4, 2) |
80 | #define __weakref_visible static |
81 | #else |
82 | #define __weakref_visible extern |
83 | #endif |
84 | |
85 | #define __warn_references(sym,msg) \ |
86 | __asm(".pushsection .gnu.warning." #sym "\n" \ |
87 | ".ascii \"" msg "\"\n" \ |
88 | ".popsection"); |
89 | |
90 | #else /* !__STDC__ */ |
91 | |
92 | #ifdef __LEADING_UNDERSCORE |
93 | #define __weak_alias(alias,sym) ___weak_alias(_/**/alias,_/**/sym) |
94 | #define ___weak_alias(alias,sym) \ |
95 | __asm(".weak alias\nalias = sym"); |
96 | #else |
97 | #define __weak_alias(alias,sym) \ |
98 | __asm(".weak alias\nalias = sym"); |
99 | #endif |
100 | #ifdef __LEADING_UNDERSCORE |
101 | #define __weak_extern(sym) ___weak_extern(_/**/sym) |
102 | #define ___weak_extern(sym) \ |
103 | __asm(".weak sym"); |
104 | #else |
105 | #define __weak_extern(sym) \ |
106 | __asm(".weak sym"); |
107 | #endif |
108 | #define __warn_references(sym,msg) \ |
109 | __asm(".pushsection .gnu.warning.sym\n" \ |
110 | ".ascii \"" msg "\"\n" \ |
111 | ".popsection"); |
112 | |
113 | #endif /* !__STDC__ */ |
114 | |
115 | #if __arm__ |
116 | #define __ifunc(name, resolver) \ |
117 | __asm(".globl " _C_LABEL_STRING(#name) "\n" \ |
118 | ".type " _C_LABEL_STRING(#name) ", %gnu_indirect_function\n" \ |
119 | _C_LABEL_STRING(#name) " = " _C_LABEL_STRING(#resolver)) |
120 | #else |
121 | #define __ifunc(name, resolver) \ |
122 | __asm(".globl " _C_LABEL_STRING(#name) "\n" \ |
123 | ".type " _C_LABEL_STRING(#name) ", @gnu_indirect_function\n" \ |
124 | _C_LABEL_STRING(#name) " = " _C_LABEL_STRING(#resolver)) |
125 | #endif |
126 | |
127 | #if __STDC__ |
128 | #define __SECTIONSTRING(_sec, _str) \ |
129 | __asm(".pushsection " #_sec "\n" \ |
130 | ".asciz \"" _str "\"\n" \ |
131 | ".popsection") |
132 | #else |
133 | #define __SECTIONSTRING(_sec, _str) \ |
134 | __asm(".pushsection _sec\n" \ |
135 | ".asciz \"" _str "\"\n" \ |
136 | ".popsection") |
137 | #endif |
138 | |
139 | #define __IDSTRING(_n,_s) __SECTIONSTRING(.ident,_s) |
140 | |
141 | #define __RCSID(_s) __IDSTRING(rcsid,_s) |
142 | #define __SCCSID(_s) |
143 | #define __SCCSID2(_s) |
144 | #define __COPYRIGHT(_s) __SECTIONSTRING(.copyright,_s) |
145 | |
146 | #define __KERNEL_RCSID(_n, _s) __RCSID(_s) |
147 | #define __KERNEL_SCCSID(_n, _s) |
148 | #define __KERNEL_COPYRIGHT(_n, _s) __COPYRIGHT(_s) |
149 | |
150 | #ifndef __lint__ |
151 | #define __link_set_make_entry(set, sym) \ |
152 | static void const * const __link_set_##set##_sym_##sym \ |
153 | __section("link_set_" #set) __used = (const void *)&sym |
154 | #define __link_set_make_entry2(set, sym, n) \ |
155 | static void const * const __link_set_##set##_sym_##sym##_##n \ |
156 | __section("link_set_" #set) __used = (const void *)&sym[n] |
157 | #else |
158 | #define __link_set_make_entry(set, sym) \ |
159 | extern void const * const __link_set_##set##_sym_##sym |
160 | #define __link_set_make_entry2(set, sym, n) \ |
161 | extern void const * const __link_set_##set##_sym_##sym##_##n |
162 | #endif /* __lint__ */ |
163 | |
164 | #define __link_set_add_text(set, sym) __link_set_make_entry(set, sym) |
165 | #define __link_set_add_rodata(set, sym) __link_set_make_entry(set, sym) |
166 | #define __link_set_add_data(set, sym) __link_set_make_entry(set, sym) |
167 | #define __link_set_add_bss(set, sym) __link_set_make_entry(set, sym) |
168 | #define __link_set_add_text2(set, sym, n) __link_set_make_entry2(set, sym, n) |
169 | #define __link_set_add_rodata2(set, sym, n) __link_set_make_entry2(set, sym, n) |
170 | #define __link_set_add_data2(set, sym, n) __link_set_make_entry2(set, sym, n) |
171 | #define __link_set_add_bss2(set, sym, n) __link_set_make_entry2(set, sym, n) |
172 | |
173 | #define __link_set_start(set) (__start_link_set_##set) |
174 | #define __link_set_end(set) (__stop_link_set_##set) |
175 | |
176 | #define __link_set_decl(set, ptype) \ |
177 | extern ptype * const __link_set_start(set)[] __dso_hidden; \ |
178 | __asm__(".hidden " __STRING(__stop_link_set_##set)); \ |
179 | extern ptype * const __link_set_end(set)[] __weak __dso_hidden |
180 | |
181 | #define __link_set_count(set) \ |
182 | (__link_set_end(set) - __link_set_start(set)) |
183 | |
184 | |
185 | #ifdef _KERNEL |
186 | |
187 | /* |
188 | * On multiprocessor systems we can gain an improvement in performance |
189 | * by being mindful of which cachelines data is placed in. |
190 | * |
191 | * __read_mostly: |
192 | * |
193 | * It makes sense to ensure that rarely modified data is not |
194 | * placed in the same cacheline as frequently modified data. |
195 | * To mitigate the phenomenon known as "false-sharing" we |
196 | * can annotate rarely modified variables with __read_mostly. |
197 | * All such variables are placed into the .data.read_mostly |
198 | * section in the kernel ELF. |
199 | * |
200 | * Prime candidates for __read_mostly annotation are variables |
201 | * which are hardly ever modified and which are used in code |
202 | * hot-paths, e.g. pmap_initialized. |
203 | * |
204 | * __cacheline_aligned: |
205 | * |
206 | * Some data structures (mainly locks) benefit from being aligned |
207 | * on a cacheline boundary, and having a cacheline to themselves. |
208 | * This way, the modification of other data items cannot adversely |
209 | * affect the lock and vice versa. |
210 | * |
211 | * Any variables annotated with __cacheline_aligned will be |
212 | * placed into the .data.cacheline_aligned ELF section. |
213 | */ |
214 | #define __read_mostly \ |
215 | __attribute__((__section__(".data.read_mostly"))) |
216 | |
217 | #define __cacheline_aligned \ |
218 | __attribute__((__aligned__(COHERENCY_UNIT), \ |
219 | __section__(".data.cacheline_aligned"))) |
220 | |
221 | #endif /* _KERNEL */ |
222 | |
223 | #endif /* !_SYS_CDEFS_ELF_H_ */ |
224 | |