1/* Machine-dependent ELF dynamic relocation functions. PowerPC version.
2 Copyright (C) 1995-2024 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#include <unistd.h>
20#include <string.h>
21#include <sys/param.h>
22#include <link.h>
23#include <ldsodefs.h>
24#include <elf/dynamic-link.h>
25#include <dl-machine.h>
26#include <_itoa.h>
27
28/* Stuff for the PLT. */
29#define PLT_INITIAL_ENTRY_WORDS 18
30#define PLT_LONGBRANCH_ENTRY_WORDS 0
31#define PLT_TRAMPOLINE_ENTRY_WORDS 6
32#define PLT_DOUBLE_SIZE (1<<13)
33#define PLT_ENTRY_START_WORDS(entry_number) \
34 (PLT_INITIAL_ENTRY_WORDS + (entry_number)*2 \
35 + ((entry_number) > PLT_DOUBLE_SIZE \
36 ? ((entry_number) - PLT_DOUBLE_SIZE)*2 \
37 : 0))
38#define PLT_DATA_START_WORDS(num_entries) PLT_ENTRY_START_WORDS(num_entries)
39
40/* Macros to build PowerPC opcode words. */
41#define OPCODE_ADDI(rd,ra,simm) \
42 (0x38000000 | (rd) << 21 | (ra) << 16 | ((simm) & 0xffff))
43#define OPCODE_ADDIS(rd,ra,simm) \
44 (0x3c000000 | (rd) << 21 | (ra) << 16 | ((simm) & 0xffff))
45#define OPCODE_ADD(rd,ra,rb) \
46 (0x7c000214 | (rd) << 21 | (ra) << 16 | (rb) << 11)
47#define OPCODE_B(target) (0x48000000 | ((target) & 0x03fffffc))
48#define OPCODE_BA(target) (0x48000002 | ((target) & 0x03fffffc))
49#define OPCODE_BCTR() 0x4e800420
50#define OPCODE_LWZ(rd,d,ra) \
51 (0x80000000 | (rd) << 21 | (ra) << 16 | ((d) & 0xffff))
52#define OPCODE_LWZU(rd,d,ra) \
53 (0x84000000 | (rd) << 21 | (ra) << 16 | ((d) & 0xffff))
54#define OPCODE_MTCTR(rd) (0x7C0903A6 | (rd) << 21)
55#define OPCODE_RLWINM(ra,rs,sh,mb,me) \
56 (0x54000000 | (rs) << 21 | (ra) << 16 | (sh) << 11 | (mb) << 6 | (me) << 1)
57
58#define OPCODE_LI(rd,simm) OPCODE_ADDI(rd,0,simm)
59#define OPCODE_ADDIS_HI(rd,ra,value) \
60 OPCODE_ADDIS(rd,ra,((value) + 0x8000) >> 16)
61#define OPCODE_LIS_HI(rd,value) OPCODE_ADDIS_HI(rd,0,value)
62#define OPCODE_SLWI(ra,rs,sh) OPCODE_RLWINM(ra,rs,sh,0,31-sh)
63
64
65#define PPC_DCBST(where) asm volatile ("dcbst 0,%0" : : "r"(where) : "memory")
66#define PPC_SYNC asm volatile ("sync" : : : "memory")
67#define PPC_ISYNC asm volatile ("sync; isync" : : : "memory")
68#define PPC_ICBI(where) asm volatile ("icbi 0,%0" : : "r"(where) : "memory")
69#define PPC_DIE asm volatile ("tweq 0,0")
70
71/* Use this when you've modified some code, but it won't be in the
72 instruction fetch queue (or when it doesn't matter if it is). */
73#define MODIFIED_CODE_NOQUEUE(where) \
74 do { PPC_DCBST(where); PPC_SYNC; PPC_ICBI(where); } while (0)
75/* Use this when it might be in the instruction queue. */
76#define MODIFIED_CODE(where) \
77 do { PPC_DCBST(where); PPC_SYNC; PPC_ICBI(where); PPC_ISYNC; } while (0)
78
79
80/* The idea here is that to conform to the ABI, we are supposed to try
81 to load dynamic objects between 0x10000 (we actually use 0x40000 as
82 the lower bound, to increase the chance of a memory reference from
83 a null pointer giving a segfault) and the program's load address;
84 this may allow us to use a branch instruction in the PLT rather
85 than a computed jump. The address is only used as a preference for
86 mmap, so if we get it wrong the worst that happens is that it gets
87 mapped somewhere else. */
88
89ElfW(Addr)
90__elf_preferred_address (struct link_map *loader, size_t maplength,
91 ElfW(Addr) mapstartpref)
92{
93 ElfW(Addr) low, high;
94 struct link_map *l;
95 Lmid_t nsid;
96
97 /* If the object has a preference, load it there! */
98 if (mapstartpref != 0)
99 return mapstartpref;
100
101 /* Otherwise, quickly look for a suitable gap between 0x3FFFF and
102 0x70000000. 0x3FFFF is so that references off NULL pointers will
103 cause a segfault, 0x70000000 is just paranoia (it should always
104 be superseded by the program's load address). */
105 low = 0x0003FFFF;
106 high = 0x70000000;
107 for (nsid = 0; nsid < DL_NNS; ++nsid)
108 for (l = GL(dl_ns)[nsid]._ns_loaded; l; l = l->l_next)
109 {
110 ElfW(Addr) mapstart, mapend;
111 mapstart = l->l_map_start & ~(GLRO(dl_pagesize) - 1);
112 mapend = l->l_map_end | (GLRO(dl_pagesize) - 1);
113 assert (mapend > mapstart);
114
115 /* Prefer gaps below the main executable, note that l ==
116 _dl_loaded does not work for static binaries loading
117 e.g. libnss_*.so. */
118 if ((mapend >= high || l->l_type == lt_executable)
119 && high >= mapstart)
120 high = mapstart;
121 else if (mapend >= low && low >= mapstart)
122 low = mapend;
123 else if (high >= mapend && mapstart >= low)
124 {
125 if (high - mapend >= mapstart - low)
126 low = mapend;
127 else
128 high = mapstart;
129 }
130 }
131
132 high -= 0x10000; /* Allow some room between objects. */
133 maplength = (maplength | (GLRO(dl_pagesize) - 1)) + 1;
134 if (high <= low || high - low < maplength )
135 return 0;
136 return high - maplength; /* Both high and maplength are page-aligned. */
137}
138
139/* Set up the loaded object described by L so its unrelocated PLT
140 entries will jump to the on-demand fixup code in dl-runtime.c.
141 Also install a small trampoline to be used by entries that have
142 been relocated to an address too far away for a single branch. */
143
144/* There are many kinds of PLT entries:
145
146 (1) A direct jump to the actual routine, either a relative or
147 absolute branch. These are set up in __elf_machine_fixup_plt.
148
149 (2) Short lazy entries. These cover the first 8192 slots in
150 the PLT, and look like (where 'index' goes from 0 to 8191):
151
152 li %r11, index*4
153 b &plt[PLT_TRAMPOLINE_ENTRY_WORDS+1]
154
155 (3) Short indirect jumps. These replace (2) when a direct jump
156 wouldn't reach. They look the same except that the branch
157 is 'b &plt[PLT_LONGBRANCH_ENTRY_WORDS]'.
158
159 (4) Long lazy entries. These cover the slots when a short entry
160 won't fit ('index*4' overflows its field), and look like:
161
162 lis %r11, %hi(index*4 + &plt[PLT_DATA_START_WORDS])
163 lwzu %r12, %r11, %lo(index*4 + &plt[PLT_DATA_START_WORDS])
164 b &plt[PLT_TRAMPOLINE_ENTRY_WORDS]
165 bctr
166
167 (5) Long indirect jumps. These replace (4) when a direct jump
168 wouldn't reach. They look like:
169
170 lis %r11, %hi(index*4 + &plt[PLT_DATA_START_WORDS])
171 lwz %r12, %r11, %lo(index*4 + &plt[PLT_DATA_START_WORDS])
172 mtctr %r12
173 bctr
174
175 (6) Long direct jumps. These are used when thread-safety is not
176 required. They look like:
177
178 lis %r12, %hi(finaladdr)
179 addi %r12, %r12, %lo(finaladdr)
180 mtctr %r12
181 bctr
182
183
184 The lazy entries, (2) and (4), are set up here in
185 __elf_machine_runtime_setup. (1), (3), and (5) are set up in
186 __elf_machine_fixup_plt. (1), (3), and (6) can also be constructed
187 in __process_machine_rela.
188
189 The reason for the somewhat strange construction of the long
190 entries, (4) and (5), is that we need to ensure thread-safety. For
191 (1) and (3), this is obvious because only one instruction is
192 changed and the PPC architecture guarantees that aligned stores are
193 atomic. For (5), this is more tricky. When changing (4) to (5),
194 the `b' instruction is first changed to `mtctr'; this is safe
195 and is why the `lwzu' instruction is not just a simple `addi'.
196 Once this is done, and is visible to all processors, the `lwzu' can
197 safely be changed to a `lwz'. */
198int
199__elf_machine_runtime_setup (struct link_map *map, int lazy, int profile)
200{
201 if (map->l_info[DT_JMPREL])
202 {
203 Elf32_Word i;
204 Elf32_Word *plt = (Elf32_Word *) D_PTR (map, l_info[DT_PLTGOT]);
205 Elf32_Word num_plt_entries = (map->l_info[DT_PLTRELSZ]->d_un.d_val
206 / sizeof (Elf32_Rela));
207 Elf32_Word rel_offset_words = PLT_DATA_START_WORDS (num_plt_entries);
208 Elf32_Word data_words = (Elf32_Word) (plt + rel_offset_words);
209 Elf32_Word size_modified;
210
211 extern void _dl_runtime_resolve (void);
212 extern void _dl_prof_resolve (void);
213
214 /* Convert the index in r11 into an actual address, and get the
215 word at that address. */
216 plt[PLT_LONGBRANCH_ENTRY_WORDS] = OPCODE_ADDIS_HI (11, 11, data_words);
217 plt[PLT_LONGBRANCH_ENTRY_WORDS + 1] = OPCODE_LWZ (11, data_words, 11);
218
219 /* Call the procedure at that address. */
220 plt[PLT_LONGBRANCH_ENTRY_WORDS + 2] = OPCODE_MTCTR (11);
221 plt[PLT_LONGBRANCH_ENTRY_WORDS + 3] = OPCODE_BCTR ();
222
223 if (lazy)
224 {
225 Elf32_Word *tramp = plt + PLT_TRAMPOLINE_ENTRY_WORDS;
226 Elf32_Word dlrr;
227 Elf32_Word offset;
228
229#if !defined PROF && defined SHARED
230 dlrr = (Elf32_Word) (profile
231 ? _dl_prof_resolve
232 : _dl_runtime_resolve);
233 if (profile && GLRO(dl_profile) != NULL
234 && _dl_name_match_p (GLRO(dl_profile), map))
235 /* This is the object we are looking for. Say that we really
236 want profiling and the timers are started. */
237 GL(dl_profile_map) = map;
238#else
239 dlrr = (Elf32_Word) _dl_runtime_resolve;
240#endif
241
242 /* For the long entries, subtract off data_words. */
243 tramp[0] = OPCODE_ADDIS_HI (11, 11, -data_words);
244 tramp[1] = OPCODE_ADDI (11, 11, -data_words);
245
246 /* Multiply index of entry by 3 (in r11). */
247 tramp[2] = OPCODE_SLWI (12, 11, 1);
248 tramp[3] = OPCODE_ADD (11, 12, 11);
249 if (dlrr <= 0x01fffffc || dlrr >= 0xfe000000)
250 {
251 /* Load address of link map in r12. */
252 tramp[4] = OPCODE_LI (12, (Elf32_Word) map);
253 tramp[5] = OPCODE_ADDIS_HI (12, 12, (Elf32_Word) map);
254
255 /* Call _dl_runtime_resolve. */
256 tramp[6] = OPCODE_BA (dlrr);
257 }
258 else
259 {
260 /* Get address of _dl_runtime_resolve in CTR. */
261 tramp[4] = OPCODE_LI (12, dlrr);
262 tramp[5] = OPCODE_ADDIS_HI (12, 12, dlrr);
263 tramp[6] = OPCODE_MTCTR (12);
264
265 /* Load address of link map in r12. */
266 tramp[7] = OPCODE_LI (12, (Elf32_Word) map);
267 tramp[8] = OPCODE_ADDIS_HI (12, 12, (Elf32_Word) map);
268
269 /* Call _dl_runtime_resolve. */
270 tramp[9] = OPCODE_BCTR ();
271 }
272
273 /* Set up the lazy PLT entries. */
274 offset = PLT_INITIAL_ENTRY_WORDS;
275 i = 0;
276 while (i < num_plt_entries && i < PLT_DOUBLE_SIZE)
277 {
278 plt[offset ] = OPCODE_LI (11, i * 4);
279 plt[offset+1] = OPCODE_B ((PLT_TRAMPOLINE_ENTRY_WORDS + 2
280 - (offset+1))
281 * 4);
282 i++;
283 offset += 2;
284 }
285 while (i < num_plt_entries)
286 {
287 plt[offset ] = OPCODE_LIS_HI (11, i * 4 + data_words);
288 plt[offset+1] = OPCODE_LWZU (12, i * 4 + data_words, 11);
289 plt[offset+2] = OPCODE_B ((PLT_TRAMPOLINE_ENTRY_WORDS
290 - (offset+2))
291 * 4);
292 plt[offset+3] = OPCODE_BCTR ();
293 i++;
294 offset += 4;
295 }
296 }
297
298 /* Now, we've modified code. We need to write the changes from
299 the data cache to a second-level unified cache, then make
300 sure that stale data in the instruction cache is removed.
301 (In a multiprocessor system, the effect is more complex.)
302 Most of the PLT shouldn't be in the instruction cache, but
303 there may be a little overlap at the start and the end.
304
305 Assumes that dcbst and icbi apply to lines of 16 bytes or
306 more. Current known line sizes are 16, 32, and 128 bytes.
307 The following gets the cache line size, when available. */
308
309 /* Default minimum 4 words per cache line. */
310 int line_size_words = 4;
311
312 if (lazy && GLRO(dl_cache_line_size) != 0)
313 /* Convert bytes to words. */
314 line_size_words = GLRO(dl_cache_line_size) / 4;
315
316 size_modified = lazy ? rel_offset_words : 6;
317 for (i = 0; i < size_modified; i += line_size_words)
318 PPC_DCBST (plt + i);
319 PPC_DCBST (plt + size_modified - 1);
320 PPC_SYNC;
321
322 for (i = 0; i < size_modified; i += line_size_words)
323 PPC_ICBI (plt + i);
324 PPC_ICBI (plt + size_modified - 1);
325 PPC_ISYNC;
326 }
327
328 return lazy;
329}
330
331Elf32_Addr
332__elf_machine_fixup_plt (struct link_map *map,
333 Elf32_Addr *reloc_addr, Elf32_Addr finaladdr)
334{
335 Elf32_Sword delta = finaladdr - (Elf32_Word) reloc_addr;
336 if (delta << 6 >> 6 == delta)
337 *reloc_addr = OPCODE_B (delta);
338 else if (finaladdr <= 0x01fffffc || finaladdr >= 0xfe000000)
339 *reloc_addr = OPCODE_BA (finaladdr);
340 else
341 {
342 Elf32_Word *plt, *data_words;
343 Elf32_Word index, offset, num_plt_entries;
344
345 num_plt_entries = (map->l_info[DT_PLTRELSZ]->d_un.d_val
346 / sizeof (Elf32_Rela));
347 plt = (Elf32_Word *) D_PTR (map, l_info[DT_PLTGOT]);
348 offset = reloc_addr - plt;
349 index = (offset - PLT_INITIAL_ENTRY_WORDS)/2;
350 data_words = plt + PLT_DATA_START_WORDS (num_plt_entries);
351
352 reloc_addr += 1;
353
354 if (index < PLT_DOUBLE_SIZE)
355 {
356 data_words[index] = finaladdr;
357 PPC_SYNC;
358 *reloc_addr = OPCODE_B ((PLT_LONGBRANCH_ENTRY_WORDS - (offset+1))
359 * 4);
360 }
361 else
362 {
363 index -= (index - PLT_DOUBLE_SIZE)/2;
364
365 data_words[index] = finaladdr;
366 PPC_SYNC;
367
368 reloc_addr[1] = OPCODE_MTCTR (12);
369 MODIFIED_CODE_NOQUEUE (reloc_addr + 1);
370 PPC_SYNC;
371
372 reloc_addr[0] = OPCODE_LWZ (12,
373 (Elf32_Word) (data_words + index), 11);
374 }
375 }
376 MODIFIED_CODE (reloc_addr);
377 return finaladdr;
378}
379
380void
381_dl_reloc_overflow (struct link_map *map,
382 const char *name,
383 Elf32_Addr *const reloc_addr,
384 const Elf32_Sym *refsym)
385{
386 char buffer[128];
387 char *t;
388 t = stpcpy (buffer, name);
389 t = stpcpy (t, " relocation at 0x00000000");
390 _itoa_word (value: (unsigned) reloc_addr, buflim: t, base: 16, upper_case: 0);
391 if (refsym)
392 {
393 const char *strtab;
394
395 strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
396 t = stpcpy (t, " for symbol `");
397 t = stpcpy (t, strtab + refsym->st_name);
398 t = stpcpy (t, "'");
399 }
400 t = stpcpy (t, " out of range");
401 _dl_signal_error (errcode: 0, object: map->l_name, NULL, errstring: buffer);
402}
403
404void
405__process_machine_rela (struct link_map *map,
406 const Elf32_Rela *reloc,
407 struct link_map *sym_map,
408 const Elf32_Sym *sym,
409 const Elf32_Sym *refsym,
410 Elf32_Addr *const reloc_addr,
411 Elf32_Addr const finaladdr,
412 int rinfo, bool skip_ifunc)
413{
414 union unaligned
415 {
416 uint16_t u2;
417 uint32_t u4;
418 } __attribute__((__packed__));
419
420 switch (rinfo)
421 {
422 case R_PPC_NONE:
423 return;
424
425 case R_PPC_ADDR32:
426 case R_PPC_GLOB_DAT:
427 case R_PPC_RELATIVE:
428 *reloc_addr = finaladdr;
429 return;
430
431 case R_PPC_IRELATIVE:
432 if (__glibc_likely (!skip_ifunc))
433 *reloc_addr = ((Elf32_Addr (*) (void)) finaladdr) ();
434 return;
435
436 case R_PPC_UADDR32:
437 ((union unaligned *) reloc_addr)->u4 = finaladdr;
438 break;
439
440 case R_PPC_ADDR24:
441 if (__glibc_unlikely (finaladdr > 0x01fffffc && finaladdr < 0xfe000000))
442 _dl_reloc_overflow (map, name: "R_PPC_ADDR24", reloc_addr, refsym);
443 *reloc_addr = (*reloc_addr & 0xfc000003) | (finaladdr & 0x3fffffc);
444 break;
445
446 case R_PPC_ADDR16:
447 if (__glibc_unlikely (finaladdr > 0x7fff && finaladdr < 0xffff8000))
448 _dl_reloc_overflow (map, name: "R_PPC_ADDR16", reloc_addr, refsym);
449 *(Elf32_Half*) reloc_addr = finaladdr;
450 break;
451
452 case R_PPC_UADDR16:
453 if (__glibc_unlikely (finaladdr > 0x7fff && finaladdr < 0xffff8000))
454 _dl_reloc_overflow (map, name: "R_PPC_UADDR16", reloc_addr, refsym);
455 ((union unaligned *) reloc_addr)->u2 = finaladdr;
456 break;
457
458 case R_PPC_ADDR16_LO:
459 *(Elf32_Half*) reloc_addr = finaladdr;
460 break;
461
462 case R_PPC_ADDR16_HI:
463 *(Elf32_Half*) reloc_addr = finaladdr >> 16;
464 break;
465
466 case R_PPC_ADDR16_HA:
467 *(Elf32_Half*) reloc_addr = (finaladdr + 0x8000) >> 16;
468 break;
469
470 case R_PPC_ADDR14:
471 case R_PPC_ADDR14_BRTAKEN:
472 case R_PPC_ADDR14_BRNTAKEN:
473 if (__glibc_unlikely (finaladdr > 0x7fff && finaladdr < 0xffff8000))
474 _dl_reloc_overflow (map, name: "R_PPC_ADDR14", reloc_addr, refsym);
475 *reloc_addr = (*reloc_addr & 0xffff0003) | (finaladdr & 0xfffc);
476 if (rinfo != R_PPC_ADDR14)
477 *reloc_addr = ((*reloc_addr & 0xffdfffff)
478 | ((rinfo == R_PPC_ADDR14_BRTAKEN)
479 ^ (finaladdr >> 31)) << 21);
480 break;
481
482 case R_PPC_REL24:
483 {
484 Elf32_Sword delta = finaladdr - (Elf32_Word) reloc_addr;
485 if (delta << 6 >> 6 != delta)
486 _dl_reloc_overflow (map, name: "R_PPC_REL24", reloc_addr, refsym);
487 *reloc_addr = (*reloc_addr & 0xfc000003) | (delta & 0x3fffffc);
488 }
489 break;
490
491 case R_PPC_COPY:
492 if (sym == NULL)
493 /* This can happen in trace mode when an object could not be
494 found. */
495 return;
496 if (sym->st_size > refsym->st_size
497 || (GLRO(dl_verbose) && sym->st_size < refsym->st_size))
498 {
499 const char *strtab;
500
501 strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
502 _dl_error_printf (fmt: "\
503%s: Symbol `%s' has different size in shared object, consider re-linking\n",
504 RTLD_PROGNAME, strtab + refsym->st_name);
505 }
506 memcpy (reloc_addr, (char *) finaladdr, MIN (sym->st_size,
507 refsym->st_size));
508 return;
509
510 case R_PPC_REL32:
511 *reloc_addr = finaladdr - (Elf32_Word) reloc_addr;
512 return;
513
514 case R_PPC_JMP_SLOT:
515 /* It used to be that elf_machine_fixup_plt was used here,
516 but that doesn't work when ld.so relocates itself
517 for the second time. On the bright side, there's
518 no need to worry about thread-safety here. */
519 {
520 Elf32_Sword delta = finaladdr - (Elf32_Word) reloc_addr;
521 if (delta << 6 >> 6 == delta)
522 *reloc_addr = OPCODE_B (delta);
523 else if (finaladdr <= 0x01fffffc || finaladdr >= 0xfe000000)
524 *reloc_addr = OPCODE_BA (finaladdr);
525 else
526 {
527 Elf32_Word *plt, *data_words;
528 Elf32_Word index, offset, num_plt_entries;
529
530 plt = (Elf32_Word *) D_PTR (map, l_info[DT_PLTGOT]);
531 offset = reloc_addr - plt;
532
533 if (offset < PLT_DOUBLE_SIZE*2 + PLT_INITIAL_ENTRY_WORDS)
534 {
535 index = (offset - PLT_INITIAL_ENTRY_WORDS)/2;
536 num_plt_entries = (map->l_info[DT_PLTRELSZ]->d_un.d_val
537 / sizeof (Elf32_Rela));
538 data_words = plt + PLT_DATA_START_WORDS (num_plt_entries);
539 data_words[index] = finaladdr;
540 reloc_addr[0] = OPCODE_LI (11, index * 4);
541 reloc_addr[1] = OPCODE_B ((PLT_LONGBRANCH_ENTRY_WORDS
542 - (offset+1))
543 * 4);
544 MODIFIED_CODE_NOQUEUE (reloc_addr + 1);
545 }
546 else
547 {
548 reloc_addr[0] = OPCODE_LIS_HI (12, finaladdr);
549 reloc_addr[1] = OPCODE_ADDI (12, 12, finaladdr);
550 reloc_addr[2] = OPCODE_MTCTR (12);
551 reloc_addr[3] = OPCODE_BCTR ();
552 MODIFIED_CODE_NOQUEUE (reloc_addr + 3);
553 }
554 }
555 }
556 break;
557
558#define DO_TLS_RELOC(suffix) \
559 case R_PPC_DTPREL##suffix: \
560 /* During relocation all TLS symbols are defined and used. \
561 Therefore the offset is already correct. */ \
562 if (sym_map != NULL) \
563 do_reloc##suffix ("R_PPC_DTPREL"#suffix, \
564 TLS_DTPREL_VALUE (sym, reloc)); \
565 break; \
566 case R_PPC_TPREL##suffix: \
567 if (sym_map != NULL) \
568 { \
569 CHECK_STATIC_TLS (map, sym_map); \
570 do_reloc##suffix ("R_PPC_TPREL"#suffix, \
571 TLS_TPREL_VALUE (sym_map, sym, reloc)); \
572 } \
573 break;
574
575 inline void do_reloc16 (const char *r_name, Elf32_Addr value)
576 {
577 if (__glibc_unlikely (value > 0x7fff && value < 0xffff8000))
578 _dl_reloc_overflow (map, r_name, reloc_addr, refsym);
579 *(Elf32_Half *) reloc_addr = value;
580 }
581 inline void do_reloc16_LO (const char *r_name, Elf32_Addr value)
582 {
583 *(Elf32_Half *) reloc_addr = value;
584 }
585 inline void do_reloc16_HI (const char *r_name, Elf32_Addr value)
586 {
587 *(Elf32_Half *) reloc_addr = value >> 16;
588 }
589 inline void do_reloc16_HA (const char *r_name, Elf32_Addr value)
590 {
591 *(Elf32_Half *) reloc_addr = (value + 0x8000) >> 16;
592 }
593 DO_TLS_RELOC (16)
594 DO_TLS_RELOC (16_LO)
595 DO_TLS_RELOC (16_HI)
596 DO_TLS_RELOC (16_HA)
597
598 default:
599 _dl_reloc_bad_type (map, type: rinfo, plt: 0);
600 return;
601 }
602
603 MODIFIED_CODE_NOQUEUE (reloc_addr);
604}
605

source code of glibc/sysdeps/powerpc/powerpc32/dl-machine.c