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1/* Machine-dependent ELF dynamic relocation inline functions. Nios II version.
2 Copyright (C) 1995-2019 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 <http://www.gnu.org/licenses/>. */
18
19#ifndef dl_machine_h
20#define dl_machine_h
21
22#define ELF_MACHINE_NAME "nios2"
23
24#include <string.h>
25#include <link.h>
26#include <dl-tls.h>
27
28/* Return nonzero iff ELF header is compatible with the running host. */
29static inline int
30elf_machine_matches_host (const Elf32_Ehdr *ehdr)
31{
32 return ehdr->e_machine == EM_ALTERA_NIOS2;
33}
34
35
36/* Return the link-time address of _DYNAMIC. Conveniently, this is the
37 first element of the GOT. */
38static inline Elf32_Addr
39elf_machine_dynamic (void)
40{
41 Elf32_Addr *dynamic;
42 int tmp;
43 asm ("nextpc\t%0\n\t"
44 "1: movhi\t%1, %%hiadj(_GLOBAL_OFFSET_TABLE_ - 1b)\n\t"
45 "addi\t%1, %1, %%lo(_GLOBAL_OFFSET_TABLE_ - 1b)\n\t"
46 "add\t%0, %0, %1\n"
47 : "=r" (dynamic), "=r" (tmp));
48 return *dynamic;
49}
50
51
52/* Return the run-time load address of the shared object. */
53static inline Elf32_Addr
54elf_machine_load_address (void)
55{
56 Elf32_Addr result;
57 int tmp;
58 asm ("nextpc\t%0\n\t"
59 "1: movhi\t%1, %%hiadj(1b)\n\t"
60 "addi\t%1, %1, %%lo(1b)\n\t"
61 "sub\t%0, %0, %1\n"
62 : "=r" (result), "=r" (tmp));
63 return result;
64}
65
66/* Set up the loaded object described by L so its unrelocated PLT
67 entries will jump to the on-demand fixup code in dl-runtime.c. */
68
69static inline int __attribute__ ((always_inline))
70elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
71{
72 extern void _dl_runtime_resolve (Elf32_Word);
73
74 if (l->l_info[DT_JMPREL] && lazy)
75 {
76 /* The GOT entries for functions in the PLT have not yet been filled
77 in. Their initial contents will arrange when called to load r15 with
78 an offset into the .got section, load r14 with
79 _GLOBAL_OFFSET_TABLE_[1], and then jump to _GLOBAL_OFFSET_TABLE[2].
80 */
81 Elf32_Addr *got = (Elf32_Addr *) D_PTR (l, l_info[DT_PLTGOT]);
82 got[1] = (Elf32_Addr) l; /* Identify this shared object. */
83
84 /* This function will get called to fix up the GOT entry indicated by
85 the offset on the stack, and then jump to the resolved address. */
86 got[2] = (Elf32_Addr) &_dl_runtime_resolve;
87 }
88
89 return lazy;
90}
91
92/* Initial entry point code for the dynamic linker.
93 The C function `_dl_start' is the real entry point;
94 its return value is the user program's entry point. */
95
96#define RTLD_START asm ("\
97.text\n\
98.globl _start\n\
99.type _start, %function\n\
100_start:\n\
101 /* At start time, all the args are on the stack. */\n\
102 mov r4, sp\n\
103\n\
104 /* Start the calculation of the GOT pointer. */\n\
105 nextpc r22\n\
1061: movhi r8, %hiadj(_gp_got - 1b)\n\
107 addi r8, r8, %lo(_gp_got - 1b)\n\
108\n\
109 /* Figure out where _dl_start will need to return to. */\n\
110 movhi ra, %hiadj(2f - 1b)\n\
111 addi ra, ra, %lo(2f - 1b)\n\
112 add ra, ra, r22\n\
113\n\
114 /* Finish the calculation of the GOT pointer. */\n\
115 add r22, r22, r8\n\
116\n\
117 br _dl_start\n\
118\n\
119 /* Save the returned user entry point. */\n\
1202: mov r16, r2\n\
121\n\
122 /* Initialize gp. */\n\
123 ldw r4, %got(_rtld_local)(r22)\n\
124 ldw r4, 0(r4)\n\
125 ldw r8, %call(_dl_nios2_get_gp_value)(r22)\n\
126 callr r8\n\
127 mov gp, r2\n\
128\n\
129 /* Find the number of arguments to skip. */\n\
130 ldw r8, %got(_dl_skip_args)(r22)\n\
131 ldw r8, 0(r8)\n\
132\n\
133 /* Find the main_map from the GOT. */\n\
134 ldw r4, %got(_rtld_local)(r22)\n\
135 ldw r4, 0(r4)\n\
136\n\
137 /* Find argc. */\n\
138 ldw r5, 0(sp)\n\
139 sub r5, r5, r8\n\
140 stw r5, 0(sp)\n\
141\n\
142 /* Find the first unskipped argument. */\n\
143 slli r8, r8, 2\n\
144 addi r6, sp, 4\n\
145 add r9, r6, r8\n\
146 mov r10, r6\n\
147\n\
148 /* Shuffle argv down. */\n\
1493: ldw r11, 0(r9)\n\
150 stw r11, 0(r10)\n\
151 addi r9, r9, 4\n\
152 addi r10, r10, 4\n\
153 bne r11, zero, 3b\n\
154\n\
155 /* Shuffle envp down. */\n\
156 mov r7, r10\n\
1574: ldw r11, 0(r9)\n\
158 stw r11, 0(r10)\n\
159 addi r9, r9, 4\n\
160 addi r10, r10, 4\n\
161 bne r11, zero, 4b\n\
162\n\
163 /* Shuffle auxv down. */\n\
1645: ldw r11, 4(r9)\n\
165 stw r11, 4(r10)\n\
166 ldw r11, 0(r9)\n\
167 stw r11, 0(r10)\n\
168 addi r9, r9, 8\n\
169 addi r10, r10, 8\n\
170 bne r11, zero, 5b\n\
171\n\
172 /* Update _dl_argv. */\n\
173 ldw r2, %got(_dl_argv)(r22)\n\
174 stw r6, 0(r2)\n\
175\n\
176 /* Call _dl_init through the PLT. */\n\
177 ldw r8, %call(_dl_init)(r22)\n\
178 callr r8\n\
179\n\
180 /* Find the finalization function. */\n\
181 ldw r4, %got(_dl_fini)(r22)\n\
182\n\
183 /* Jump to the user's entry point. */\n\
184 jmp r16\n\
185");
186
187/* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry, so
188 PLT entries should not be allowed to define the value.
189 ELF_RTYPE_CLASS_COPY iff TYPE should not be allowed to resolve to one
190 of the main executable's symbols, as for a COPY reloc. */
191#define elf_machine_type_class(type) \
192 ((((type) == R_NIOS2_JUMP_SLOT \
193 || (type) == R_NIOS2_TLS_DTPMOD \
194 || (type) == R_NIOS2_TLS_DTPREL \
195 || (type) == R_NIOS2_TLS_TPREL) * ELF_RTYPE_CLASS_PLT) \
196 | (((type) == R_NIOS2_COPY) * ELF_RTYPE_CLASS_COPY) \
197 | (((type) == R_NIOS2_GLOB_DAT) * ELF_RTYPE_CLASS_EXTERN_PROTECTED_DATA))
198
199/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
200#define ELF_MACHINE_JMP_SLOT R_NIOS2_JUMP_SLOT
201
202/* The Nios II never uses Elf32_Rel relocations. */
203#define ELF_MACHINE_NO_REL 1
204#define ELF_MACHINE_NO_RELA 0
205
206/* Fixup a PLT entry to bounce directly to the function at VALUE. */
207
208static inline Elf32_Addr
209elf_machine_fixup_plt (struct link_map *map, lookup_t t,
210 const ElfW(Sym) *refsym, const ElfW(Sym) *sym,
211 const Elf32_Rela *reloc,
212 Elf32_Addr *reloc_addr, Elf32_Addr value)
213{
214 return *reloc_addr = value;
215}
216
217/* Return the final value of a plt relocation. */
218static inline Elf32_Addr
219elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc,
220 Elf32_Addr value)
221{
222 return value;
223}
224
225/* Names of the architecture-specific auditing callback functions. */
226#define ARCH_LA_PLTENTER nios2_gnu_pltenter
227#define ARCH_LA_PLTEXIT nios2_gnu_pltexit
228
229#endif /* dl_machine_h */
230
231#ifdef RESOLVE_MAP
232
233/* Perform the relocation specified by RELOC and SYM (which is fully resolved).
234 LOADADDR is the load address of the object; INFO is an array indexed
235 by DT_* of the .dynamic section info. */
236
237auto inline void __attribute__ ((always_inline))
238elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
239 const ElfW(Sym) *sym, const struct r_found_version *version,
240 void *const reloc_addr_arg, int skip_ifunc)
241{
242 Elf32_Addr *const reloc_addr = reloc_addr_arg;
243 const unsigned int r_type = ELF32_R_TYPE (reloc->r_info);
244
245 if (__glibc_unlikely (r_type == R_NIOS2_RELATIVE))
246 *reloc_addr = map->l_addr + reloc->r_addend;
247 else if (__glibc_unlikely (r_type == R_NIOS2_NONE))
248 return;
249 else
250 {
251 const Elf32_Sym *const refsym = sym;
252 struct link_map *sym_map = RESOLVE_MAP (&sym, version, r_type);
253 Elf32_Addr value = SYMBOL_ADDRESS (sym_map, sym, true);
254
255 switch (r_type)
256 {
257 case R_NIOS2_COPY:
258 if (sym == NULL)
259 /* This can happen in trace mode if an object could not be
260 found. */
261 break;
262 if (sym->st_size > refsym->st_size
263 || (sym->st_size < refsym->st_size && GLRO(dl_verbose)))
264 {
265 const char *strtab;
266
267 strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
268 _dl_error_printf ("\
269%s: Symbol `%s' has different size in shared object, consider re-linking\n",
270 rtld_progname ?: "<program name unknown>",
271 strtab + refsym->st_name);
272 }
273 memcpy (reloc_addr_arg, (void *) value,
274 MIN (sym->st_size, refsym->st_size));
275 break;
276 case R_NIOS2_GLOB_DAT:
277 case R_NIOS2_JUMP_SLOT:
278# ifdef RTLD_BOOTSTRAP
279 /* Fix weak undefined references. */
280 if (sym != NULL && sym->st_value == 0)
281 *reloc_addr = 0;
282 else
283# endif
284 *reloc_addr = value;
285 break;
286#ifndef RTLD_BOOTSTRAP
287 case R_NIOS2_TLS_DTPMOD:
288 /* Get the information from the link map returned by the
289 resolv function. */
290 if (sym_map != NULL)
291 *reloc_addr = sym_map->l_tls_modid;
292 break;
293
294 case R_NIOS2_TLS_DTPREL:
295 *reloc_addr = reloc->r_addend + TLS_DTPREL_VALUE(sym);
296 break;
297
298 case R_NIOS2_TLS_TPREL:
299 if (sym != NULL)
300 {
301 CHECK_STATIC_TLS (map, sym_map);
302 *reloc_addr = reloc->r_addend + TLS_TPREL_VALUE(sym_map, sym);
303 }
304 break;
305#endif
306 case R_NIOS2_BFD_RELOC_32:
307 *reloc_addr = value + reloc->r_addend;
308 break;
309
310 default:
311 _dl_reloc_bad_type (map, r_type, 0);
312 break;
313 }
314 }
315}
316
317auto inline void __attribute__((always_inline))
318elf_machine_rela_relative (ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
319 void *const reloc_addr_arg)
320{
321 Elf32_Addr *const reloc_addr = reloc_addr_arg;
322 *reloc_addr = l_addr + reloc->r_addend;
323}
324
325auto inline void __attribute__((always_inline))
326elf_machine_lazy_rel (struct link_map *map,
327 ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
328 int skip_ifunc)
329{
330 Elf32_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
331 if (ELF32_R_TYPE (reloc->r_info) == R_NIOS2_JUMP_SLOT)
332 *reloc_addr += l_addr;
333 else
334 _dl_reloc_bad_type (map, ELF32_R_TYPE (reloc->r_info), 1);
335}
336
337#endif /* RESOLVE_MAP */
338

Warning: That file was not part of the compilation database. It may have many parsing errors.