1 /* Copyright (C) 1995-2021 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
elf_machine_matches_host(const Elf32_Ehdr * ehdr)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
elf_machine_dynamic(void)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
elf_machine_load_address(void)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))
elf_machine_runtime_setup(struct link_map * l,struct r_scope_elem * scope[],int lazy,int profile)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 r4,r20,_dl_skip_args@GOTOFF\n\
121 lwi r5,r1,24\n\
122 rsubk r5,r4,r5\n\
123 addk r4,r4,r4\n\
124 addk r4,r4,r4\n\
125 addk r1,r1,r4\n\
126 swi r5,r1,24\n\
127 swi r3,r1,20\n\
128 addk r6,r5,r0\n\
129 addk r5,r5,r5\n\
130 addk r5,r5,r5\n\
131 addik r7,r1,28\n\
132 addk r8,r7,r5\n\
133 addik r8,r8,4\n\
134 lwi r5,r20,_rtld_local@GOTOFF\n\
135 brlid r15,_dl_init\n\
136 nop\n\
137 lwi r5,r1,24\n\
138 lwi r3,r1,20\n\
139 addk r4,r5,r5\n\
140 addk r4,r4,r4\n\
141 addik r6,r1,28\n\
142 addk r7,r6,r4\n\
143 addik r7,r7,4\n\
144 addik r15,r20,_dl_fini@GOTOFF\n\
145 addik r15,r15,-8\n\
146 brad r3\n\
147 addik r1,r1,24\n\
148 nop\n\
149 .size _dl_start_user, . - _dl_start_user\n\
150 .previous");
151
152 /* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or
153 TLS variable, so undefined references should not be allowed to
154 define the value.
155 ELF_RTYPE_CLASS_COPY iff TYPE should not be allowed to resolve to one
156 of the main executable's symbols, as for a COPY reloc. */
157 #ifndef RTLD_BOOTSTRAP
158 # define elf_machine_type_class(type) \
159 (((type) == R_MICROBLAZE_JUMP_SLOT \
160 || (type) == R_MICROBLAZE_TLSDTPREL32 \
161 || (type) == R_MICROBLAZE_TLSDTPMOD32 \
162 || (type) == R_MICROBLAZE_TLSTPREL32) \
163 * ELF_RTYPE_CLASS_PLT \
164 | ((type) == R_MICROBLAZE_COPY) * ELF_RTYPE_CLASS_COPY)
165 #else
166 # define elf_machine_type_class(type) \
167 (((type) == R_MICROBLAZE_JUMP_SLOT) * ELF_RTYPE_CLASS_PLT \
168 | ((type) == R_MICROBLAZE_COPY) * ELF_RTYPE_CLASS_COPY)
169 #endif
170
171 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
172 #define ELF_MACHINE_JMP_SLOT R_MICROBLAZE_JUMP_SLOT
173
174 static inline Elf32_Addr
elf_machine_fixup_plt(struct link_map * map,lookup_t t,const ElfW (Sym)* refsym,const ElfW (Sym)* sym,const Elf32_Rela * reloc,Elf32_Addr * reloc_addr,Elf32_Addr value)175 elf_machine_fixup_plt (struct link_map *map, lookup_t t,
176 const ElfW(Sym) *refsym, const ElfW(Sym) *sym,
177 const Elf32_Rela *reloc,
178 Elf32_Addr *reloc_addr, Elf32_Addr value)
179 {
180 return *reloc_addr = value;
181 }
182
183 /* Return the final value of a plt relocation. Ignore the addend. */
184 static inline Elf32_Addr
elf_machine_plt_value(struct link_map * map,const Elf32_Rela * reloc,Elf32_Addr value)185 elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc,
186 Elf32_Addr value)
187 {
188 return value;
189 }
190
191 #endif /* !dl_machine_h. */
192
193 /* Names of the architecture-specific auditing callback functions. */
194 #define ARCH_LA_PLTENTER microblaze_gnu_pltenter
195 #define ARCH_LA_PLTEXIT microblaze_gnu_pltexit
196
197 #ifdef RESOLVE_MAP
198
199 /* Perform the relocation specified by RELOC and SYM (which is fully resolved).
200 MAP is the object containing the reloc. */
201
202 /* Macro to put 32-bit relocation value into 2 words. */
203 #define PUT_REL_64(rel_addr,val) \
204 do { \
205 ((unsigned short *)(rel_addr))[1] = (val) >> 16; \
206 ((unsigned short *)(rel_addr))[3] = (val) & 0xffff; \
207 } while (0)
208
209 static inline void __attribute__ ((always_inline))
elf_machine_rela(struct link_map * map,struct r_scope_elem * scope[],const Elf32_Rela * reloc,const Elf32_Sym * sym,const struct r_found_version * version,void * const reloc_addr_arg,int skip_ifunc)210 elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
211 const Elf32_Rela *reloc, const Elf32_Sym *sym,
212 const struct r_found_version *version,
213 void *const reloc_addr_arg, int skip_ifunc)
214 {
215 Elf32_Addr *const reloc_addr = reloc_addr_arg;
216 const int r_type = ELF32_R_TYPE (reloc->r_info);
217
218 if (__builtin_expect (r_type == R_MICROBLAZE_64_PCREL, 0))
219 PUT_REL_64 (reloc_addr, map->l_addr + reloc->r_addend);
220 else if (r_type == R_MICROBLAZE_REL)
221 *reloc_addr = map->l_addr + reloc->r_addend;
222 else
223 {
224 const Elf32_Sym *const refsym = sym;
225 struct link_map *sym_map = RESOLVE_MAP (map, scope, &sym, version,
226 r_type);
227 Elf32_Addr value = SYMBOL_ADDRESS (sym_map, sym, true);
228
229 value += reloc->r_addend;
230 if (r_type == R_MICROBLAZE_GLOB_DAT
231 || r_type == R_MICROBLAZE_JUMP_SLOT
232 || r_type == R_MICROBLAZE_32)
233 {
234 *reloc_addr = value;
235 }
236 else if (r_type == R_MICROBLAZE_COPY)
237 {
238 if (sym != NULL && (sym->st_size > refsym->st_size
239 || (sym->st_size < refsym->st_size && GLRO (dl_verbose))) )
240 {
241 const char *strtab;
242
243 strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
244 _dl_error_printf ("\
245 %s: Symbol `%s' has different size in shared object, consider re-linking\n",
246 RTLD_PROGNAME, strtab + refsym->st_name);
247 }
248 memcpy (reloc_addr_arg, (void *) value,
249 MIN (sym->st_size, refsym->st_size));
250 }
251 else if (r_type == R_MICROBLAZE_NONE)
252 {
253 }
254 #if !defined RTLD_BOOTSTRAP
255 else if (r_type == R_MICROBLAZE_TLSDTPMOD32)
256 {
257 if (sym_map != NULL)
258 *reloc_addr = sym_map->l_tls_modid;
259 }
260 else if (r_type == R_MICROBLAZE_TLSDTPREL32)
261 {
262 if (sym != NULL)
263 *reloc_addr = sym->st_value + reloc->r_addend;
264 }
265 else if (r_type == R_MICROBLAZE_TLSTPREL32)
266 {
267 if (sym != NULL)
268 {
269 CHECK_STATIC_TLS (map, sym_map);
270 *reloc_addr = sym->st_value + sym_map->l_tls_offset + reloc->r_addend;
271 }
272 }
273 #endif
274 else
275 {
276 _dl_reloc_bad_type (map, r_type, 0);
277 }
278 }
279 }
280
281 static inline void
elf_machine_rela_relative(Elf32_Addr l_addr,const Elf32_Rela * reloc,void * const reloc_addr_arg)282 elf_machine_rela_relative (Elf32_Addr l_addr, const Elf32_Rela *reloc,
283 void *const reloc_addr_arg)
284 {
285 Elf32_Addr *const reloc_addr = reloc_addr_arg;
286 PUT_REL_64 (reloc_addr, l_addr + reloc->r_addend);
287 }
288
289 static inline void
elf_machine_lazy_rel(struct link_map * map,struct r_scope_elem * scope[],Elf32_Addr l_addr,const Elf32_Rela * reloc,int skip_ifunc)290 elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
291 Elf32_Addr l_addr, const Elf32_Rela *reloc,
292 int skip_ifunc)
293 {
294 Elf32_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
295 if (ELF32_R_TYPE (reloc->r_info) == R_MICROBLAZE_JUMP_SLOT)
296 *reloc_addr += l_addr;
297 else
298 _dl_reloc_bad_type (map, ELF32_R_TYPE (reloc->r_info), 1);
299 }
300
301 #endif /* RESOLVE_MAP. */
302