1 /* Machine-dependent ELF dynamic relocation inline functions. IA-64 version.
2 Copyright (C) 1995-2023 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 #ifndef dl_machine_h
20 #define dl_machine_h 1
21
22 #define ELF_MACHINE_NAME "ia64"
23
24 #include <assert.h>
25 #include <string.h>
26 #include <link.h>
27 #include <errno.h>
28 #include <dl-fptr.h>
29 #include <tls.h>
30 #include <dl-static-tls.h>
31 #include <dl-machine-rel.h>
32
33 /* Translate a processor specific dynamic tag to the index
34 in l_info array. */
35 #define DT_IA_64(x) (DT_IA_64_##x - DT_LOPROC + DT_NUM)
36
37 static inline void __attribute__ ((always_inline))
38 __ia64_init_bootstrap_fdesc_table (struct link_map *map)
39 {
40 Elf64_Addr *boot_table;
41
42 /* careful: this will be called before got has been relocated... */
43 asm (";; addl %0 = @gprel (_dl_boot_fptr_table), gp" : "=r"(boot_table));
44
45 map->l_mach.fptr_table_len = ELF_MACHINE_BOOT_FPTR_TABLE_LEN;
46 map->l_mach.fptr_table = boot_table;
47 }
48
49 #define ELF_MACHINE_BEFORE_RTLD_RELOC(map, dynamic_info) \
50 __ia64_init_bootstrap_fdesc_table (map);
51
52 /* Return nonzero iff ELF header is compatible with the running host. */
53 static inline int __attribute__ ((unused))
54 elf_machine_matches_host (const Elf64_Ehdr *ehdr)
55 {
56 return ehdr->e_machine == EM_IA_64;
57 }
58
59
60 /* Return the link-time address of _DYNAMIC. */
61 static inline Elf64_Addr __attribute__ ((unused, const))
62 elf_machine_dynamic (void)
63 {
64 Elf64_Addr *p;
65
66 __asm__ (
67 ".section .sdata\n"
68 " .type __dynamic_ltv#, @object\n"
69 " .size __dynamic_ltv#, 8\n"
70 "__dynamic_ltv:\n"
71 " data8 @ltv(_DYNAMIC#)\n"
72 ".previous\n"
73 " addl %0 = @gprel(__dynamic_ltv#), gp ;;"
74 : "=r" (p));
75
76 return *p;
77 }
78
79
80 /* Return the run-time load address of the shared object. */
81 static inline Elf64_Addr __attribute__ ((unused))
82 elf_machine_load_address (void)
83 {
84 Elf64_Addr ip;
85 int *p;
86
87 __asm__ (
88 "1: mov %0 = ip\n"
89 ".section .sdata\n"
90 "2: data4 @ltv(1b)\n"
91 " .align 8\n"
92 ".previous\n"
93 " addl %1 = @gprel(2b), gp ;;"
94 : "=r" (ip), "=r" (p));
95
96 return ip - (Elf64_Addr) *p;
97 }
98
99 /* Set up the loaded object described by L so its unrelocated PLT
100 entries will jump to the on-demand fixup code in dl-runtime.c. */
101
102 static inline int __attribute__ ((unused, always_inline))
103 elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
104 int lazy, int profile)
105 {
106 extern void _dl_runtime_resolve (void);
107 extern void _dl_runtime_profile (void);
108
109 if (lazy)
110 {
111 register Elf64_Addr gp __asm__ ("gp");
112 Elf64_Addr *reserve, doit;
113
114 /*
115 * Careful with the typecast here or it will try to add l-l_addr
116 * pointer elements
117 */
118 reserve = ((Elf64_Addr *)
119 (l->l_info[DT_IA_64 (PLT_RESERVE)]->d_un.d_ptr + l->l_addr));
120 /* Identify this shared object. */
121 reserve[0] = (Elf64_Addr) l;
122
123 /* This function will be called to perform the relocation. */
124 if (!profile)
125 doit = (Elf64_Addr) ELF_PTR_TO_FDESC (&_dl_runtime_resolve)->ip;
126 else
127 {
128 if (GLRO(dl_profile) != NULL
129 && _dl_name_match_p (GLRO(dl_profile), l))
130 {
131 /* This is the object we are looking for. Say that we really
132 want profiling and the timers are started. */
133 GL(dl_profile_map) = l;
134 }
135 doit = (Elf64_Addr) ELF_PTR_TO_FDESC (&_dl_runtime_profile)->ip;
136 }
137
138 reserve[1] = doit;
139 reserve[2] = gp;
140 }
141
142 return lazy;
143 }
144
145 /* Names of the architecture-specific auditing callback functions. */
146 #define ARCH_LA_PLTENTER ia64_gnu_pltenter
147 #define ARCH_LA_PLTEXIT ia64_gnu_pltexit
148
149 /* Undo the adds out0 = 16, sp below to get at the value we want in
150 __libc_stack_end. */
151 #define DL_STACK_END(cookie) \
152 ((void *) (((long) (cookie)) - 16))
153
154 /* Initial entry point code for the dynamic linker.
155 The C function `_dl_start' is the real entry point;
156 its return value is the user program's entry point. */
157
158 #define RTLD_START asm ( \
159 ".text\n" \
160 " .global _start#\n" \
161 " .proc _start#\n" \
162 "_start:\n" \
163 "0: { .mii\n" \
164 " .prologue\n" \
165 " .save rp, r0\n" \
166 " .body\n" \
167 " .prologue\n" \
168 " .save ar.pfs, r32\n" \
169 " alloc loc0 = ar.pfs, 0, 3, 4, 0\n" \
170 " .body\n" \
171 " mov r2 = ip\n" \
172 " addl r3 = @gprel(0b), r0\n" \
173 " ;;\n" \
174 " }\n" \
175 " { .mlx\n" \
176 " /* Calculate the GP, and save a copy in loc1. */\n" \
177 " sub gp = r2, r3\n" \
178 " movl r8 = 0x9804c0270033f\n" \
179 " ;;\n" \
180 " }\n" \
181 " { .mii\n" \
182 " mov ar.fpsr = r8\n" \
183 " sub loc1 = r2, r3\n" \
184 " /* _dl_start wants a pointer to the pointer to the arg block and\n" \
185 " the arg block starts with an integer, thus the magic 16. */\n" \
186 " adds out0 = 16, sp\n" \
187 " }\n" \
188 " { .bbb\n" \
189 " br.call.sptk.many b0 = _dl_start#\n" \
190 " ;;\n" \
191 " }\n" \
192 " .endp _start#\n" \
193 " /* FALLTHRU */\n" \
194 " .global _dl_start_user#\n" \
195 " .proc _dl_start_user#\n" \
196 "_dl_start_user:\n" \
197 " .prologue\n" \
198 " .save rp, r0\n" \
199 " .body\n" \
200 " .prologue\n" \
201 " .save ar.pfs, r32\n" \
202 " .body\n" \
203 " { .mii\n" \
204 " /* Save the pointer to the user entry point fptr in loc2. */\n" \
205 " mov loc2 = ret0\n" \
206 " addl r2 = @ltoff(_dl_argc), gp\n" \
207 " ;;\n" \
208 " }\n" \
209 " { .mii\n" \
210 " ld8 out1 = [r2] /* Get the _dl_argc address. */\n" \
211 " addl r3 = @ltoff(_dl_argv), gp\n" \
212 " ;;\n" \
213 " }\n" \
214 " { .mmi\n" \
215 " ld8 out2 = [r3] /* Get the _dl_argv address. */\n" \
216 " ld8 out1 = [out1] /* Get the adjusted _dl_argc. */\n" \
217 " addl r2 = @gprel(_rtld_local), gp\n" \
218 " ;;\n" \
219 " }\n" \
220 " { .mmi\n" \
221 " sxt4 out3 = out1 /* envp = argv + argc + 1 */\n" \
222 " ;;\n" \
223 " }\n" \
224 " { .mmi\n" \
225 " adds out3 = 1, out3\n" \
226 " ;;\n" \
227 " }\n" \
228 " { .mmi\n" \
229 " ld8 out2 = [out2] /* Get the adjusted _dl_argv. */\n" \
230 " shladd out3 = out3, 3, r0\n" \
231 " ;;\n" \
232 " }\n" \
233 " { .mmb\n" \
234 " add out3 = out3, out2\n" \
235 " ld8 out0 = [r2] /* Get the linkmap. */\n" \
236 " br.call.sptk.many b0 = _dl_init#\n" \
237 " }\n" \
238 " /* Pass our finalizer function to the user,\n" \
239 " and jump to the user's entry point. */\n" \
240 " { .mmi\n" \
241 " ld8 r3 = [loc2], 8\n" \
242 " mov b0 = r0\n" \
243 " }\n" \
244 " { .mmi\n" \
245 " addl ret0 = @ltoff(@fptr(_dl_fini#)), gp\n" \
246 " ;;\n" \
247 " mov b6 = r3\n" \
248 " }\n" \
249 " { .mmi\n" \
250 " ld8 ret0 = [ret0]\n" \
251 " ld8 gp = [loc2]\n" \
252 " mov ar.pfs = loc0\n" \
253 " ;;\n" \
254 " }\n" \
255 " { .mfb\n" \
256 " br.sptk.many b6\n" \
257 " ;;\n" \
258 " }\n" \
259 " .endp _dl_start_user#\n" \
260 ".previous\n");
261
262
263 #ifndef RTLD_START_SPECIAL_INIT
264 #define RTLD_START_SPECIAL_INIT /* nothing */
265 #endif
266
267 /* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or TLS
268 variable, so undefined references should not be allowed to define the
269 value.
270 ELF_RTYPE_CLASS_COPY iff TYPE should not be allowed to resolve to one
271 of the main executable's symbols, as for a COPY reloc, which we don't
272 use. */
273 /* ??? Ignore *MSB for now. */
274 #define elf_machine_type_class(type) \
275 (((type) == R_IA64_IPLTLSB || (type) == R_IA64_DTPMOD64LSB \
276 || (type) == R_IA64_DTPREL64LSB || (type) == R_IA64_TPREL64LSB) \
277 * ELF_RTYPE_CLASS_PLT)
278
279 /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */
280 #define ELF_MACHINE_JMP_SLOT R_IA64_IPLTLSB
281
282 /* Return the address of the entry point. */
283 #define ELF_MACHINE_START_ADDRESS(map, start) \
284 ({ \
285 ElfW(Addr) addr; \
286 DL_DT_FUNCTION_ADDRESS(map, start, static, addr) \
287 addr; \
288 })
289
290 /* Fixup a PLT entry to bounce directly to the function at VALUE. */
291 static inline struct fdesc __attribute__ ((always_inline))
292 elf_machine_fixup_plt (struct link_map *l, lookup_t t,
293 const ElfW(Sym) *refsym, const ElfW(Sym) *sym,
294 const Elf64_Rela *reloc,
295 Elf64_Addr *reloc_addr, struct fdesc value)
296 {
297 /* l is the link_map for the caller, t is the link_map for the object
298 * being called */
299 /* got has already been relocated in elf_get_dynamic_info() */
300 reloc_addr[1] = value.gp;
301 /* we need a "release" here to ensure that the gp is visible before
302 the code entry point is updated: */
303 ((volatile Elf64_Addr *) reloc_addr)[0] = value.ip;
304 return value;
305 }
306
307 /* Return the final value of a plt relocation. */
308 static inline struct fdesc
309 elf_machine_plt_value (struct link_map *map, const Elf64_Rela *reloc,
310 struct fdesc value)
311 {
312 /* No need to handle rel vs rela since IA64 is rela only */
313 return (struct fdesc) { value.ip + reloc->r_addend, value.gp };
314 }
315
316 #endif /* !dl_machine_h */
317
318 #ifdef RESOLVE_MAP
319
320 #define R_IA64_TYPE(R) ((R) & -8)
321 #define R_IA64_FORMAT(R) ((R) & 7)
322
323 #define R_IA64_FORMAT_32MSB 4
324 #define R_IA64_FORMAT_32LSB 5
325 #define R_IA64_FORMAT_64MSB 6
326 #define R_IA64_FORMAT_64LSB 7
327
328
329 /* Perform the relocation specified by RELOC and SYM (which is fully
330 resolved). MAP is the object containing the reloc. */
331 static inline void
332 __attribute ((always_inline))
333 elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
334 const Elf64_Rela *reloc,
335 const Elf64_Sym *sym,
336 const struct r_found_version *version,
337 void *const reloc_addr_arg,
338 int skip_ifunc)
339 {
340 Elf64_Addr *const reloc_addr = reloc_addr_arg;
341 const unsigned long int r_type = ELF64_R_TYPE (reloc->r_info);
342 Elf64_Addr value;
343
344 /* We cannot use a switch here because we cannot locate the switch
345 jump table until we've self-relocated. */
346
347 #if !defined RTLD_BOOTSTRAP
348 if (__builtin_expect (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_REL64LSB),
349 0))
350 {
351 assert (ELF64_R_TYPE (reloc->r_info) == R_IA64_REL64LSB);
352 value = *reloc_addr + map->l_addr;
353 }
354 else
355 #endif
356 if (__builtin_expect (r_type == R_IA64_NONE, 0))
357 return;
358 else
359 {
360 struct link_map *sym_map = RESOLVE_MAP (map, scope, &sym, version,
361 r_type);
362
363 /* RESOLVE_MAP() will return NULL if it fail to locate the symbol. */
364 if (sym_map != NULL)
365 {
366 value = SYMBOL_ADDRESS (sym_map, sym, true) + reloc->r_addend;
367
368 if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_DIR64LSB))
369 ;/* No adjustment. */
370 else if (r_type == R_IA64_IPLTLSB)
371 {
372 elf_machine_fixup_plt (NULL, NULL, NULL, NULL, reloc, reloc_addr,
373 DL_FIXUP_MAKE_VALUE (sym_map, value));
374 return;
375 }
376 else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_FPTR64LSB))
377 value = _dl_make_fptr (sym_map, sym, value);
378 else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_PCREL64LSB))
379 value -= (Elf64_Addr) reloc_addr & -16;
380 else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_DTPMOD64LSB))
381 #ifdef RTLD_BOOTSTRAP
382 /* During startup the dynamic linker is always index 1. */
383 value = 1;
384 #else
385 /* Get the information from the link map returned by the
386 resolv function. */
387 value = sym_map->l_tls_modid;
388 else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_DTPREL64LSB))
389 value -= sym_map->l_addr;
390 #endif
391 else if (R_IA64_TYPE (r_type) == R_IA64_TYPE (R_IA64_TPREL64LSB))
392 {
393 #ifndef RTLD_BOOTSTRAP
394 CHECK_STATIC_TLS (map, sym_map);
395 #endif
396 value += sym_map->l_tls_offset - sym_map->l_addr;
397 }
398 else
399 _dl_reloc_bad_type (map, r_type, 0);
400 }
401 else
402 value = 0;
403 }
404
405 /* ??? Ignore MSB and Instruction format for now. */
406 if (R_IA64_FORMAT (r_type) == R_IA64_FORMAT_64LSB)
407 *reloc_addr = value;
408 else if (R_IA64_FORMAT (r_type) == R_IA64_FORMAT_32LSB)
409 *(int *) reloc_addr = value;
410 else if (r_type == R_IA64_IPLTLSB)
411 {
412 reloc_addr[0] = 0;
413 reloc_addr[1] = 0;
414 }
415 else
416 _dl_reloc_bad_type (map, r_type, 0);
417 }
418
419 /* Let do-rel.h know that on IA-64 if l_addr is 0, all RELATIVE relocs
420 can be skipped. */
421 #define ELF_MACHINE_REL_RELATIVE 1
422
423 static inline void
424 __attribute ((always_inline))
425 elf_machine_rela_relative (Elf64_Addr l_addr, const Elf64_Rela *reloc,
426 void *const reloc_addr_arg)
427 {
428 Elf64_Addr *const reloc_addr = reloc_addr_arg;
429 /* ??? Ignore MSB and Instruction format for now. */
430 assert (ELF64_R_TYPE (reloc->r_info) == R_IA64_REL64LSB);
431
432 *reloc_addr += l_addr;
433 }
434
435 /* Perform a RELATIVE reloc on the .got entry that transfers to the .plt. */
436 static inline void
437 __attribute ((always_inline))
438 elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
439 Elf64_Addr l_addr, const Elf64_Rela *reloc,
440 int skip_ifunc)
441 {
442 Elf64_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
443 const unsigned long int r_type = ELF64_R_TYPE (reloc->r_info);
444
445 if (r_type == R_IA64_IPLTLSB)
446 {
447 reloc_addr[0] += l_addr;
448 reloc_addr[1] += l_addr;
449 }
450 else if (r_type == R_IA64_NONE)
451 return;
452 else
453 _dl_reloc_bad_type (map, r_type, 1);
454 }
455
456 #endif /* RESOLVE_MAP */