1 /* Copyright (C) 1995-2023 Free Software Foundation, Inc.
2
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 License as
7 published by the Free Software Foundation; either version 2.1 of the
8 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 #ifndef dl_machine_h
20 #define dl_machine_h
21
22 #define ELF_MACHINE_NAME "microblaze"
23
24 #include <sys/param.h>
25 #include <tls.h>
26 #include <dl-static-tls.h>
27 #include <dl-machine-rel.h>
28
29 /* Return nonzero iff ELF header is compatible with the running host. */
30 static inline int
31 elf_machine_matches_host (const Elf32_Ehdr *ehdr)
32 {
33 return (ehdr->e_machine == EM_MICROBLAZE);
34 }
35
36 /* Return the link-time address of _DYNAMIC. Conveniently, this is the
37 first element of the GOT. This must be inlined in a function which
38 uses global data. */
39 static inline Elf32_Addr
40 elf_machine_dynamic (void)
41 {
42 /* This produces a GOTOFF reloc that resolves to zero at link time, so in
43 fact just loads from the GOT register directly. By doing it without
44 an asm we can let the compiler choose any register. */
45
46 Elf32_Addr got_entry_0;
47 __asm__ __volatile__(
48 "lwi %0,r20,0"
49 :"=r"(got_entry_0)
50 );
51 return got_entry_0;
52 }
53
54 /* Return the run-time load address of the shared object. */
55 static inline Elf32_Addr
56 elf_machine_load_address (void)
57 {
58 /* Compute the difference between the runtime address of _DYNAMIC as seen
59 by a GOTOFF reference, and the link-time address found in the special
60 unrelocated first GOT entry. */
61
62 Elf32_Addr dyn;
63 __asm__ __volatile__ (
64 "addik %0,r20,_DYNAMIC@GOTOFF"
65 : "=r"(dyn)
66 );
67 return dyn - elf_machine_dynamic ();
68 }
69
70 /* Set up the loaded object described by L so its unrelocated PLT
71 entries will jump to the on-demand fixup code in dl-runtime.c. */
72
73 static inline int __attribute__ ((always_inline))
74 elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
75 int lazy, int profile)
76 {
77 extern void _dl_runtime_resolve (Elf32_Word);
78 extern void _dl_runtime_profile (Elf32_Word);
79
80 return lazy;
81 }
82
83 /* The PLT uses Elf32_Rela relocs. */
84 #define elf_machine_relplt elf_machine_rela
85
86 /* Mask identifying addresses reserved for the user program,
87 where the dynamic linker should not map anything. */
88 #define ELF_MACHINE_USER_ADDRESS_MASK 0x80000000UL
89
90 /* Initial entry point code for the dynamic linker.
91 The C function `_dl_start' is the real entry point;
92 its return value is the user program's entry point. */
93
94 #define RTLD_START asm ("\
95 .text\n\
96 .globl _start\n\
97 .type _start,@function\n\
98 _start:\n\
99 addk r5,r0,r1\n\
100 addk r3,r0,r0\n\
101 1:\n\
102 addik r5,r5,4\n\
103 lw r4,r5,r0\n\
104 bneid r4,1b\n\
105 addik r3,r3,1\n\
106 addik r3,r3,-1\n\
107 addk r5,r0,r1\n\
108 sw r3,r5,r0\n\
109 addik r1,r1,-24\n\
110 sw r15,r1,r0\n\
111 brlid r15,_dl_start\n\
112 nop\n\
113 /* FALLTHRU. */\n\
114 \n\
115 .globl _dl_start_user\n\
116 .type _dl_start_user,@function\n\
117 _dl_start_user:\n\
118 mfs r20,rpc\n\
119 addik r20,r20,_GLOBAL_OFFSET_TABLE_+8\n\
120 lwi r5,r1,24\n\
121 swi r5,r1,24\n\
122 swi r3,r1,20\n\
123 addk r6,r5,r0\n\
124 addk r5,r5,r5\n\
125 addk r5,r5,r5\n\
126 addik r7,r1,28\n\
127 addk r8,r7,r5\n\
128 addik r8,r8,4\n\
129 lwi r5,r20,_rtld_local@GOTOFF\n\
130 brlid r15,_dl_init\n\
131 nop\n\
132 lwi r5,r1,24\n\
133 lwi r3,r1,20\n\
134 addk r4,r5,r5\n\
135 addk r4,r4,r4\n\
136 addik r6,r1,28\n\
137 addk r7,r6,r4\n\
138 addik r7,r7,4\n\
139 addik r15,r20,_dl_fini@GOTOFF\n\
140 addik r15,r15,-8\n\
141 brad r3\n\
142 addik r1,r1,24\n\
143 nop\n\
144 .size _dl_start_user, . - _dl_start_user\n\
145 .previous");
146
147 /* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or
148 TLS variable, so undefined references should not be allowed to
149 define the value.
150 ELF_RTYPE_CLASS_COPY iff TYPE should not be allowed to resolve to one
151 of the main executable's symbols, as for a COPY reloc. */
152 #ifndef RTLD_BOOTSTRAP
153 # define elf_machine_type_class(type) \
154 (((type) == R_MICROBLAZE_JUMP_SLOT \
155 || (type) == R_MICROBLAZE_TLSDTPREL32 \
156 || (type) == R_MICROBLAZE_TLSDTPMOD32 \
157 || (type) == R_MICROBLAZE_TLSTPREL32) \
158 * ELF_RTYPE_CLASS_PLT \
159 | ((type) == R_MICROBLAZE_COPY) * ELF_RTYPE_CLASS_COPY)
160 #else
161 # define elf_machine_type_class(type) \
162 (((type) == R_MICROBLAZE_JUMP_SLOT) * ELF_RTYPE_CLASS_PLT \
163 | ((type) == R_MICROBLAZE_COPY) * ELF_RTYPE_CLASS_COPY)
164 #endif
165
166 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
167 #define ELF_MACHINE_JMP_SLOT R_MICROBLAZE_JUMP_SLOT
168
169 static inline Elf32_Addr
170 elf_machine_fixup_plt (struct link_map *map, lookup_t t,
171 const ElfW(Sym) *refsym, const ElfW(Sym) *sym,
172 const Elf32_Rela *reloc,
173 Elf32_Addr *reloc_addr, Elf32_Addr value)
174 {
175 return *reloc_addr = value;
176 }
177
178 /* Return the final value of a plt relocation. Ignore the addend. */
179 static inline Elf32_Addr
180 elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc,
181 Elf32_Addr value)
182 {
183 return value;
184 }
185
186 #endif /* !dl_machine_h. */
187
188 /* Names of the architecture-specific auditing callback functions. */
189 #define ARCH_LA_PLTENTER microblaze_gnu_pltenter
190 #define ARCH_LA_PLTEXIT microblaze_gnu_pltexit
191
192 #ifdef RESOLVE_MAP
193
194 /* Perform the relocation specified by RELOC and SYM (which is fully resolved).
195 MAP is the object containing the reloc. */
196
197 /* Macro to put 32-bit relocation value into 2 words. */
198 #define PUT_REL_64(rel_addr,val) \
199 do { \
200 ((unsigned short *)(rel_addr))[1] = (val) >> 16; \
201 ((unsigned short *)(rel_addr))[3] = (val) & 0xffff; \
202 } while (0)
203
204 static inline void __attribute__ ((always_inline))
205 elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
206 const Elf32_Rela *reloc, const Elf32_Sym *sym,
207 const struct r_found_version *version,
208 void *const reloc_addr_arg, int skip_ifunc)
209 {
210 Elf32_Addr *const reloc_addr = reloc_addr_arg;
211 const int r_type = ELF32_R_TYPE (reloc->r_info);
212
213 if (__builtin_expect (r_type == R_MICROBLAZE_64_PCREL, 0))
214 PUT_REL_64 (reloc_addr, map->l_addr + reloc->r_addend);
215 else if (r_type == R_MICROBLAZE_REL)
216 *reloc_addr = map->l_addr + reloc->r_addend;
217 else
218 {
219 const Elf32_Sym *const refsym = sym;
220 struct link_map *sym_map = RESOLVE_MAP (map, scope, &sym, version,
221 r_type);
222 Elf32_Addr value = SYMBOL_ADDRESS (sym_map, sym, true);
223
224 value += reloc->r_addend;
225 if (r_type == R_MICROBLAZE_GLOB_DAT
226 || r_type == R_MICROBLAZE_JUMP_SLOT
227 || r_type == R_MICROBLAZE_32)
228 {
229 *reloc_addr = value;
230 }
231 else if (r_type == R_MICROBLAZE_COPY)
232 {
233 if (sym != NULL && (sym->st_size > refsym->st_size
234 || (sym->st_size < refsym->st_size && GLRO (dl_verbose))) )
235 {
236 const char *strtab;
237
238 strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
239 _dl_error_printf ("\
240 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
241 RTLD_PROGNAME, strtab + refsym->st_name);
242 }
243 memcpy (reloc_addr_arg, (void *) value,
244 MIN (sym->st_size, refsym->st_size));
245 }
246 else if (r_type == R_MICROBLAZE_NONE)
247 {
248 }
249 #if !defined RTLD_BOOTSTRAP
250 else if (r_type == R_MICROBLAZE_TLSDTPMOD32)
251 {
252 if (sym_map != NULL)
253 *reloc_addr = sym_map->l_tls_modid;
254 }
255 else if (r_type == R_MICROBLAZE_TLSDTPREL32)
256 {
257 if (sym != NULL)
258 *reloc_addr = sym->st_value + reloc->r_addend;
259 }
260 else if (r_type == R_MICROBLAZE_TLSTPREL32)
261 {
262 if (sym != NULL)
263 {
264 CHECK_STATIC_TLS (map, sym_map);
265 *reloc_addr = sym->st_value + sym_map->l_tls_offset + reloc->r_addend;
266 }
267 }
268 #endif
269 else
270 {
271 _dl_reloc_bad_type (map, r_type, 0);
272 }
273 }
274 }
275
276 static inline void
277 elf_machine_rela_relative (Elf32_Addr l_addr, const Elf32_Rela *reloc,
278 void *const reloc_addr_arg)
279 {
280 Elf32_Addr *const reloc_addr = reloc_addr_arg;
281 PUT_REL_64 (reloc_addr, l_addr + reloc->r_addend);
282 }
283
284 static inline void
285 elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
286 Elf32_Addr l_addr, const Elf32_Rela *reloc,
287 int skip_ifunc)
288 {
289 Elf32_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
290 if (ELF32_R_TYPE (reloc->r_info) == R_MICROBLAZE_JUMP_SLOT)
291 *reloc_addr += l_addr;
292 else
293 _dl_reloc_bad_type (map, ELF32_R_TYPE (reloc->r_info), 1);
294 }
295
296 #endif /* RESOLVE_MAP. */