1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Kernel dynamically loadable module help for PARISC.
3 *
4 * The best reference for this stuff is probably the Processor-
5 * Specific ELF Supplement for PA-RISC:
6 * https://parisc.wiki.kernel.org/index.php/File:Elf-pa-hp.pdf
7 *
8 * Linux/PA-RISC Project
9 * Copyright (C) 2003 Randolph Chung <tausq at debian . org>
10 * Copyright (C) 2008 Helge Deller <deller@gmx.de>
11 *
12 * Notes:
13 * - PLT stub handling
14 * On 32bit (and sometimes 64bit) and with big kernel modules like xfs or
15 * ipv6 the relocation types R_PARISC_PCREL17F and R_PARISC_PCREL22F may
16 * fail to reach their PLT stub if we only create one big stub array for
17 * all sections at the beginning of the core or init section.
18 * Instead we now insert individual PLT stub entries directly in front of
19 * of the code sections where the stubs are actually called.
20 * This reduces the distance between the PCREL location and the stub entry
21 * so that the relocations can be fulfilled.
22 * While calculating the final layout of the kernel module in memory, the
23 * kernel module loader calls arch_mod_section_prepend() to request the
24 * to be reserved amount of memory in front of each individual section.
25 *
26 * - SEGREL32 handling
27 * We are not doing SEGREL32 handling correctly. According to the ABI, we
28 * should do a value offset, like this:
29 * if (in_init(me, (void *)val))
30 * val -= (uint32_t)me->mem[MOD_INIT_TEXT].base;
31 * else
32 * val -= (uint32_t)me->mem[MOD_TEXT].base;
33 * However, SEGREL32 is used only for PARISC unwind entries, and we want
34 * those entries to have an absolute address, and not just an offset.
35 *
36 * The unwind table mechanism has the ability to specify an offset for
37 * the unwind table; however, because we split off the init functions into
38 * a different piece of memory, it is not possible to do this using a
39 * single offset. Instead, we use the above hack for now.
40 */
41
42 #include <linux/moduleloader.h>
43 #include <linux/elf.h>
44 #include <linux/fs.h>
45 #include <linux/ftrace.h>
46 #include <linux/string.h>
47 #include <linux/kernel.h>
48 #include <linux/bug.h>
49 #include <linux/mm.h>
50 #include <linux/slab.h>
51
52 #include <asm/unwind.h>
53 #include <asm/sections.h>
54
55 #define RELOC_REACHABLE(val, bits) \
56 (( ( !((val) & (1<<((bits)-1))) && ((val)>>(bits)) != 0 ) || \
57 ( ((val) & (1<<((bits)-1))) && ((val)>>(bits)) != (((__typeof__(val))(~0))>>((bits)+2)))) ? \
58 0 : 1)
59
60 #define CHECK_RELOC(val, bits) \
61 if (!RELOC_REACHABLE(val, bits)) { \
62 printk(KERN_ERR "module %s relocation of symbol %s is out of range (0x%lx in %d bits)\n", \
63 me->name, strtab + sym->st_name, (unsigned long)val, bits); \
64 return -ENOEXEC; \
65 }
66
67 /* Maximum number of GOT entries. We use a long displacement ldd from
68 * the bottom of the table, which has a maximum signed displacement of
69 * 0x3fff; however, since we're only going forward, this becomes
70 * 0x1fff, and thus, since each GOT entry is 8 bytes long we can have
71 * at most 1023 entries.
72 * To overcome this 14bit displacement with some kernel modules, we'll
73 * use instead the unusal 16bit displacement method (see reassemble_16a)
74 * which gives us a maximum positive displacement of 0x7fff, and as such
75 * allows us to allocate up to 4095 GOT entries. */
76 #define MAX_GOTS 4095
77
78 #ifndef CONFIG_64BIT
79 struct got_entry {
80 Elf32_Addr addr;
81 };
82
83 struct stub_entry {
84 Elf32_Word insns[2]; /* each stub entry has two insns */
85 };
86 #else
87 struct got_entry {
88 Elf64_Addr addr;
89 };
90
91 struct stub_entry {
92 Elf64_Word insns[4]; /* each stub entry has four insns */
93 };
94 #endif
95
96 /* Field selection types defined by hppa */
97 #define rnd(x) (((x)+0x1000)&~0x1fff)
98 /* fsel: full 32 bits */
99 #define fsel(v,a) ((v)+(a))
100 /* lsel: select left 21 bits */
101 #define lsel(v,a) (((v)+(a))>>11)
102 /* rsel: select right 11 bits */
103 #define rsel(v,a) (((v)+(a))&0x7ff)
104 /* lrsel with rounding of addend to nearest 8k */
105 #define lrsel(v,a) (((v)+rnd(a))>>11)
106 /* rrsel with rounding of addend to nearest 8k */
107 #define rrsel(v,a) ((((v)+rnd(a))&0x7ff)+((a)-rnd(a)))
108
109 #define mask(x,sz) ((x) & ~((1<<(sz))-1))
110
111
112 /* The reassemble_* functions prepare an immediate value for
113 insertion into an opcode. pa-risc uses all sorts of weird bitfields
114 in the instruction to hold the value. */
sign_unext(int x,int len)115 static inline int sign_unext(int x, int len)
116 {
117 int len_ones;
118
119 len_ones = (1 << len) - 1;
120 return x & len_ones;
121 }
122
low_sign_unext(int x,int len)123 static inline int low_sign_unext(int x, int len)
124 {
125 int sign, temp;
126
127 sign = (x >> (len-1)) & 1;
128 temp = sign_unext(x, len-1);
129 return (temp << 1) | sign;
130 }
131
reassemble_14(int as14)132 static inline int reassemble_14(int as14)
133 {
134 return (((as14 & 0x1fff) << 1) |
135 ((as14 & 0x2000) >> 13));
136 }
137
reassemble_16a(int as16)138 static inline int reassemble_16a(int as16)
139 {
140 int s, t;
141
142 /* Unusual 16-bit encoding, for wide mode only. */
143 t = (as16 << 1) & 0xffff;
144 s = (as16 & 0x8000);
145 return (t ^ s ^ (s >> 1)) | (s >> 15);
146 }
147
148
reassemble_17(int as17)149 static inline int reassemble_17(int as17)
150 {
151 return (((as17 & 0x10000) >> 16) |
152 ((as17 & 0x0f800) << 5) |
153 ((as17 & 0x00400) >> 8) |
154 ((as17 & 0x003ff) << 3));
155 }
156
reassemble_21(int as21)157 static inline int reassemble_21(int as21)
158 {
159 return (((as21 & 0x100000) >> 20) |
160 ((as21 & 0x0ffe00) >> 8) |
161 ((as21 & 0x000180) << 7) |
162 ((as21 & 0x00007c) << 14) |
163 ((as21 & 0x000003) << 12));
164 }
165
reassemble_22(int as22)166 static inline int reassemble_22(int as22)
167 {
168 return (((as22 & 0x200000) >> 21) |
169 ((as22 & 0x1f0000) << 5) |
170 ((as22 & 0x00f800) << 5) |
171 ((as22 & 0x000400) >> 8) |
172 ((as22 & 0x0003ff) << 3));
173 }
174
175 #ifndef CONFIG_64BIT
count_gots(const Elf_Rela * rela,unsigned long n)176 static inline unsigned long count_gots(const Elf_Rela *rela, unsigned long n)
177 {
178 return 0;
179 }
180
count_fdescs(const Elf_Rela * rela,unsigned long n)181 static inline unsigned long count_fdescs(const Elf_Rela *rela, unsigned long n)
182 {
183 return 0;
184 }
185
count_stubs(const Elf_Rela * rela,unsigned long n)186 static inline unsigned long count_stubs(const Elf_Rela *rela, unsigned long n)
187 {
188 unsigned long cnt = 0;
189
190 for (; n > 0; n--, rela++)
191 {
192 switch (ELF32_R_TYPE(rela->r_info)) {
193 case R_PARISC_PCREL17F:
194 case R_PARISC_PCREL22F:
195 cnt++;
196 }
197 }
198
199 return cnt;
200 }
201 #else
count_gots(const Elf_Rela * rela,unsigned long n)202 static inline unsigned long count_gots(const Elf_Rela *rela, unsigned long n)
203 {
204 unsigned long cnt = 0;
205
206 for (; n > 0; n--, rela++)
207 {
208 switch (ELF64_R_TYPE(rela->r_info)) {
209 case R_PARISC_LTOFF21L:
210 case R_PARISC_LTOFF14R:
211 case R_PARISC_PCREL22F:
212 cnt++;
213 }
214 }
215
216 return cnt;
217 }
218
count_fdescs(const Elf_Rela * rela,unsigned long n)219 static inline unsigned long count_fdescs(const Elf_Rela *rela, unsigned long n)
220 {
221 unsigned long cnt = 0;
222
223 for (; n > 0; n--, rela++)
224 {
225 switch (ELF64_R_TYPE(rela->r_info)) {
226 case R_PARISC_FPTR64:
227 cnt++;
228 }
229 }
230
231 return cnt;
232 }
233
count_stubs(const Elf_Rela * rela,unsigned long n)234 static inline unsigned long count_stubs(const Elf_Rela *rela, unsigned long n)
235 {
236 unsigned long cnt = 0;
237
238 for (; n > 0; n--, rela++)
239 {
240 switch (ELF64_R_TYPE(rela->r_info)) {
241 case R_PARISC_PCREL22F:
242 cnt++;
243 }
244 }
245
246 return cnt;
247 }
248 #endif
249
module_arch_freeing_init(struct module * mod)250 void module_arch_freeing_init(struct module *mod)
251 {
252 kfree(mod->arch.section);
253 mod->arch.section = NULL;
254 }
255
256 /* Additional bytes needed in front of individual sections */
arch_mod_section_prepend(struct module * mod,unsigned int section)257 unsigned int arch_mod_section_prepend(struct module *mod,
258 unsigned int section)
259 {
260 /* size needed for all stubs of this section (including
261 * one additional for correct alignment of the stubs) */
262 return (mod->arch.section[section].stub_entries + 1)
263 * sizeof(struct stub_entry);
264 }
265
266 #define CONST
module_frob_arch_sections(CONST Elf_Ehdr * hdr,CONST Elf_Shdr * sechdrs,CONST char * secstrings,struct module * me)267 int module_frob_arch_sections(CONST Elf_Ehdr *hdr,
268 CONST Elf_Shdr *sechdrs,
269 CONST char *secstrings,
270 struct module *me)
271 {
272 unsigned long gots = 0, fdescs = 0, len;
273 unsigned int i;
274 struct module_memory *mod_mem;
275
276 len = hdr->e_shnum * sizeof(me->arch.section[0]);
277 me->arch.section = kzalloc(len, GFP_KERNEL);
278 if (!me->arch.section)
279 return -ENOMEM;
280
281 for (i = 1; i < hdr->e_shnum; i++) {
282 const Elf_Rela *rels = (void *)sechdrs[i].sh_addr;
283 unsigned long nrels = sechdrs[i].sh_size / sizeof(*rels);
284 unsigned int count, s;
285
286 if (strncmp(secstrings + sechdrs[i].sh_name,
287 ".PARISC.unwind", 14) == 0)
288 me->arch.unwind_section = i;
289
290 if (sechdrs[i].sh_type != SHT_RELA)
291 continue;
292
293 /* some of these are not relevant for 32-bit/64-bit
294 * we leave them here to make the code common. the
295 * compiler will do its thing and optimize out the
296 * stuff we don't need
297 */
298 gots += count_gots(rels, nrels);
299 fdescs += count_fdescs(rels, nrels);
300
301 /* XXX: By sorting the relocs and finding duplicate entries
302 * we could reduce the number of necessary stubs and save
303 * some memory. */
304 count = count_stubs(rels, nrels);
305 if (!count)
306 continue;
307
308 /* so we need relocation stubs. reserve necessary memory. */
309 /* sh_info gives the section for which we need to add stubs. */
310 s = sechdrs[i].sh_info;
311
312 /* each code section should only have one relocation section */
313 WARN_ON(me->arch.section[s].stub_entries);
314
315 /* store number of stubs we need for this section */
316 me->arch.section[s].stub_entries += count;
317 }
318
319 mod_mem = &me->mem[MOD_TEXT];
320 /* align things a bit */
321 mod_mem->size = ALIGN(mod_mem->size, 16);
322 me->arch.got_offset = mod_mem->size;
323 mod_mem->size += gots * sizeof(struct got_entry);
324
325 mod_mem->size = ALIGN(mod_mem->size, 16);
326 me->arch.fdesc_offset = mod_mem->size;
327 mod_mem->size += fdescs * sizeof(Elf_Fdesc);
328
329 me->arch.got_max = gots;
330 me->arch.fdesc_max = fdescs;
331
332 return 0;
333 }
334
335 #ifdef CONFIG_64BIT
get_got(struct module * me,unsigned long value,long addend)336 static Elf64_Word get_got(struct module *me, unsigned long value, long addend)
337 {
338 unsigned int i;
339 struct got_entry *got;
340
341 value += addend;
342
343 BUG_ON(value == 0);
344
345 got = me->mem[MOD_TEXT].base + me->arch.got_offset;
346 for (i = 0; got[i].addr; i++)
347 if (got[i].addr == value)
348 goto out;
349
350 BUG_ON(++me->arch.got_count > me->arch.got_max);
351
352 got[i].addr = value;
353 out:
354 pr_debug("GOT ENTRY %d[%lx] val %lx\n", i, i*sizeof(struct got_entry),
355 value);
356 return i * sizeof(struct got_entry);
357 }
358 #endif /* CONFIG_64BIT */
359
360 #ifdef CONFIG_64BIT
get_fdesc(struct module * me,unsigned long value)361 static Elf_Addr get_fdesc(struct module *me, unsigned long value)
362 {
363 Elf_Fdesc *fdesc = me->mem[MOD_TEXT].base + me->arch.fdesc_offset;
364
365 if (!value) {
366 printk(KERN_ERR "%s: zero OPD requested!\n", me->name);
367 return 0;
368 }
369
370 /* Look for existing fdesc entry. */
371 while (fdesc->addr) {
372 if (fdesc->addr == value)
373 return (Elf_Addr)fdesc;
374 fdesc++;
375 }
376
377 BUG_ON(++me->arch.fdesc_count > me->arch.fdesc_max);
378
379 /* Create new one */
380 fdesc->addr = value;
381 fdesc->gp = (Elf_Addr)me->mem[MOD_TEXT].base + me->arch.got_offset;
382 return (Elf_Addr)fdesc;
383 }
384 #endif /* CONFIG_64BIT */
385
386 enum elf_stub_type {
387 ELF_STUB_GOT,
388 ELF_STUB_MILLI,
389 ELF_STUB_DIRECT,
390 };
391
get_stub(struct module * me,unsigned long value,long addend,enum elf_stub_type stub_type,Elf_Addr loc0,unsigned int targetsec)392 static Elf_Addr get_stub(struct module *me, unsigned long value, long addend,
393 enum elf_stub_type stub_type, Elf_Addr loc0, unsigned int targetsec)
394 {
395 struct stub_entry *stub;
396 int __maybe_unused d;
397
398 /* initialize stub_offset to point in front of the section */
399 if (!me->arch.section[targetsec].stub_offset) {
400 loc0 -= (me->arch.section[targetsec].stub_entries + 1) *
401 sizeof(struct stub_entry);
402 /* get correct alignment for the stubs */
403 loc0 = ALIGN(loc0, sizeof(struct stub_entry));
404 me->arch.section[targetsec].stub_offset = loc0;
405 }
406
407 /* get address of stub entry */
408 stub = (void *) me->arch.section[targetsec].stub_offset;
409 me->arch.section[targetsec].stub_offset += sizeof(struct stub_entry);
410
411 /* do not write outside available stub area */
412 BUG_ON(0 == me->arch.section[targetsec].stub_entries--);
413
414
415 #ifndef CONFIG_64BIT
416 /* for 32-bit the stub looks like this:
417 * ldil L'XXX,%r1
418 * be,n R'XXX(%sr4,%r1)
419 */
420 //value = *(unsigned long *)((value + addend) & ~3); /* why? */
421
422 stub->insns[0] = 0x20200000; /* ldil L'XXX,%r1 */
423 stub->insns[1] = 0xe0202002; /* be,n R'XXX(%sr4,%r1) */
424
425 stub->insns[0] |= reassemble_21(lrsel(value, addend));
426 stub->insns[1] |= reassemble_17(rrsel(value, addend) / 4);
427
428 #else
429 /* for 64-bit we have three kinds of stubs:
430 * for normal function calls:
431 * ldd 0(%dp),%dp
432 * ldd 10(%dp), %r1
433 * bve (%r1)
434 * ldd 18(%dp), %dp
435 *
436 * for millicode:
437 * ldil 0, %r1
438 * ldo 0(%r1), %r1
439 * ldd 10(%r1), %r1
440 * bve,n (%r1)
441 *
442 * for direct branches (jumps between different section of the
443 * same module):
444 * ldil 0, %r1
445 * ldo 0(%r1), %r1
446 * bve,n (%r1)
447 */
448 switch (stub_type) {
449 case ELF_STUB_GOT:
450 d = get_got(me, value, addend);
451 if (d <= 15) {
452 /* Format 5 */
453 stub->insns[0] = 0x0f6010db; /* ldd 0(%dp),%dp */
454 stub->insns[0] |= low_sign_unext(d, 5) << 16;
455 } else {
456 /* Format 3 */
457 stub->insns[0] = 0x537b0000; /* ldd 0(%dp),%dp */
458 stub->insns[0] |= reassemble_16a(d);
459 }
460 stub->insns[1] = 0x53610020; /* ldd 10(%dp),%r1 */
461 stub->insns[2] = 0xe820d000; /* bve (%r1) */
462 stub->insns[3] = 0x537b0030; /* ldd 18(%dp),%dp */
463 break;
464 case ELF_STUB_MILLI:
465 stub->insns[0] = 0x20200000; /* ldil 0,%r1 */
466 stub->insns[1] = 0x34210000; /* ldo 0(%r1), %r1 */
467 stub->insns[2] = 0x50210020; /* ldd 10(%r1),%r1 */
468 stub->insns[3] = 0xe820d002; /* bve,n (%r1) */
469
470 stub->insns[0] |= reassemble_21(lrsel(value, addend));
471 stub->insns[1] |= reassemble_14(rrsel(value, addend));
472 break;
473 case ELF_STUB_DIRECT:
474 stub->insns[0] = 0x20200000; /* ldil 0,%r1 */
475 stub->insns[1] = 0x34210000; /* ldo 0(%r1), %r1 */
476 stub->insns[2] = 0xe820d002; /* bve,n (%r1) */
477
478 stub->insns[0] |= reassemble_21(lrsel(value, addend));
479 stub->insns[1] |= reassemble_14(rrsel(value, addend));
480 break;
481 }
482
483 #endif
484
485 return (Elf_Addr)stub;
486 }
487
488 #ifndef CONFIG_64BIT
apply_relocate_add(Elf_Shdr * sechdrs,const char * strtab,unsigned int symindex,unsigned int relsec,struct module * me)489 int apply_relocate_add(Elf_Shdr *sechdrs,
490 const char *strtab,
491 unsigned int symindex,
492 unsigned int relsec,
493 struct module *me)
494 {
495 int i;
496 Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
497 Elf32_Sym *sym;
498 Elf32_Word *loc;
499 Elf32_Addr val;
500 Elf32_Sword addend;
501 Elf32_Addr dot;
502 Elf_Addr loc0;
503 unsigned int targetsec = sechdrs[relsec].sh_info;
504 //unsigned long dp = (unsigned long)$global$;
505 register unsigned long dp asm ("r27");
506
507 pr_debug("Applying relocate section %u to %u\n", relsec,
508 targetsec);
509 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
510 /* This is where to make the change */
511 loc = (void *)sechdrs[targetsec].sh_addr
512 + rel[i].r_offset;
513 /* This is the start of the target section */
514 loc0 = sechdrs[targetsec].sh_addr;
515 /* This is the symbol it is referring to */
516 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
517 + ELF32_R_SYM(rel[i].r_info);
518 if (!sym->st_value) {
519 printk(KERN_WARNING "%s: Unknown symbol %s\n",
520 me->name, strtab + sym->st_name);
521 return -ENOENT;
522 }
523 //dot = (sechdrs[relsec].sh_addr + rel->r_offset) & ~0x03;
524 dot = (Elf32_Addr)loc & ~0x03;
525
526 val = sym->st_value;
527 addend = rel[i].r_addend;
528
529 #if 0
530 #define r(t) ELF32_R_TYPE(rel[i].r_info)==t ? #t :
531 pr_debug("Symbol %s loc 0x%x val 0x%x addend 0x%x: %s\n",
532 strtab + sym->st_name,
533 (uint32_t)loc, val, addend,
534 r(R_PARISC_PLABEL32)
535 r(R_PARISC_DIR32)
536 r(R_PARISC_DIR21L)
537 r(R_PARISC_DIR14R)
538 r(R_PARISC_SEGREL32)
539 r(R_PARISC_DPREL21L)
540 r(R_PARISC_DPREL14R)
541 r(R_PARISC_PCREL17F)
542 r(R_PARISC_PCREL22F)
543 "UNKNOWN");
544 #undef r
545 #endif
546
547 switch (ELF32_R_TYPE(rel[i].r_info)) {
548 case R_PARISC_PLABEL32:
549 /* 32-bit function address */
550 /* no function descriptors... */
551 *loc = fsel(val, addend);
552 break;
553 case R_PARISC_DIR32:
554 /* direct 32-bit ref */
555 *loc = fsel(val, addend);
556 break;
557 case R_PARISC_DIR21L:
558 /* left 21 bits of effective address */
559 val = lrsel(val, addend);
560 *loc = mask(*loc, 21) | reassemble_21(val);
561 break;
562 case R_PARISC_DIR14R:
563 /* right 14 bits of effective address */
564 val = rrsel(val, addend);
565 *loc = mask(*loc, 14) | reassemble_14(val);
566 break;
567 case R_PARISC_SEGREL32:
568 /* 32-bit segment relative address */
569 /* See note about special handling of SEGREL32 at
570 * the beginning of this file.
571 */
572 *loc = fsel(val, addend);
573 break;
574 case R_PARISC_SECREL32:
575 /* 32-bit section relative address. */
576 *loc = fsel(val, addend);
577 break;
578 case R_PARISC_DPREL21L:
579 /* left 21 bit of relative address */
580 val = lrsel(val - dp, addend);
581 *loc = mask(*loc, 21) | reassemble_21(val);
582 break;
583 case R_PARISC_DPREL14R:
584 /* right 14 bit of relative address */
585 val = rrsel(val - dp, addend);
586 *loc = mask(*loc, 14) | reassemble_14(val);
587 break;
588 case R_PARISC_PCREL17F:
589 /* 17-bit PC relative address */
590 /* calculate direct call offset */
591 val += addend;
592 val = (val - dot - 8)/4;
593 if (!RELOC_REACHABLE(val, 17)) {
594 /* direct distance too far, create
595 * stub entry instead */
596 val = get_stub(me, sym->st_value, addend,
597 ELF_STUB_DIRECT, loc0, targetsec);
598 val = (val - dot - 8)/4;
599 CHECK_RELOC(val, 17);
600 }
601 *loc = (*loc & ~0x1f1ffd) | reassemble_17(val);
602 break;
603 case R_PARISC_PCREL22F:
604 /* 22-bit PC relative address; only defined for pa20 */
605 /* calculate direct call offset */
606 val += addend;
607 val = (val - dot - 8)/4;
608 if (!RELOC_REACHABLE(val, 22)) {
609 /* direct distance too far, create
610 * stub entry instead */
611 val = get_stub(me, sym->st_value, addend,
612 ELF_STUB_DIRECT, loc0, targetsec);
613 val = (val - dot - 8)/4;
614 CHECK_RELOC(val, 22);
615 }
616 *loc = (*loc & ~0x3ff1ffd) | reassemble_22(val);
617 break;
618 case R_PARISC_PCREL32:
619 /* 32-bit PC relative address */
620 *loc = val - dot - 8 + addend;
621 break;
622
623 default:
624 printk(KERN_ERR "module %s: Unknown relocation: %u\n",
625 me->name, ELF32_R_TYPE(rel[i].r_info));
626 return -ENOEXEC;
627 }
628 }
629
630 return 0;
631 }
632
633 #else
apply_relocate_add(Elf_Shdr * sechdrs,const char * strtab,unsigned int symindex,unsigned int relsec,struct module * me)634 int apply_relocate_add(Elf_Shdr *sechdrs,
635 const char *strtab,
636 unsigned int symindex,
637 unsigned int relsec,
638 struct module *me)
639 {
640 int i;
641 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
642 Elf64_Sym *sym;
643 Elf64_Word *loc;
644 Elf64_Xword *loc64;
645 Elf64_Addr val;
646 Elf64_Sxword addend;
647 Elf64_Addr dot;
648 Elf_Addr loc0;
649 unsigned int targetsec = sechdrs[relsec].sh_info;
650
651 pr_debug("Applying relocate section %u to %u\n", relsec,
652 targetsec);
653 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
654 /* This is where to make the change */
655 loc = (void *)sechdrs[targetsec].sh_addr
656 + rel[i].r_offset;
657 /* This is the start of the target section */
658 loc0 = sechdrs[targetsec].sh_addr;
659 /* This is the symbol it is referring to */
660 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
661 + ELF64_R_SYM(rel[i].r_info);
662 if (!sym->st_value) {
663 printk(KERN_WARNING "%s: Unknown symbol %s\n",
664 me->name, strtab + sym->st_name);
665 return -ENOENT;
666 }
667 //dot = (sechdrs[relsec].sh_addr + rel->r_offset) & ~0x03;
668 dot = (Elf64_Addr)loc & ~0x03;
669 loc64 = (Elf64_Xword *)loc;
670
671 val = sym->st_value;
672 addend = rel[i].r_addend;
673
674 #if 0
675 #define r(t) ELF64_R_TYPE(rel[i].r_info)==t ? #t :
676 printk("Symbol %s loc %p val 0x%Lx addend 0x%Lx: %s\n",
677 strtab + sym->st_name,
678 loc, val, addend,
679 r(R_PARISC_LTOFF14R)
680 r(R_PARISC_LTOFF21L)
681 r(R_PARISC_PCREL22F)
682 r(R_PARISC_DIR64)
683 r(R_PARISC_SEGREL32)
684 r(R_PARISC_FPTR64)
685 "UNKNOWN");
686 #undef r
687 #endif
688
689 switch (ELF64_R_TYPE(rel[i].r_info)) {
690 case R_PARISC_LTOFF21L:
691 /* LT-relative; left 21 bits */
692 val = get_got(me, val, addend);
693 pr_debug("LTOFF21L Symbol %s loc %p val %llx\n",
694 strtab + sym->st_name,
695 loc, val);
696 val = lrsel(val, 0);
697 *loc = mask(*loc, 21) | reassemble_21(val);
698 break;
699 case R_PARISC_LTOFF14R:
700 /* L(ltoff(val+addend)) */
701 /* LT-relative; right 14 bits */
702 val = get_got(me, val, addend);
703 val = rrsel(val, 0);
704 pr_debug("LTOFF14R Symbol %s loc %p val %llx\n",
705 strtab + sym->st_name,
706 loc, val);
707 *loc = mask(*loc, 14) | reassemble_14(val);
708 break;
709 case R_PARISC_PCREL22F:
710 /* PC-relative; 22 bits */
711 pr_debug("PCREL22F Symbol %s loc %p val %llx\n",
712 strtab + sym->st_name,
713 loc, val);
714 val += addend;
715 /* can we reach it locally? */
716 if (within_module(val, me)) {
717 /* this is the case where the symbol is local
718 * to the module, but in a different section,
719 * so stub the jump in case it's more than 22
720 * bits away */
721 val = (val - dot - 8)/4;
722 if (!RELOC_REACHABLE(val, 22)) {
723 /* direct distance too far, create
724 * stub entry instead */
725 val = get_stub(me, sym->st_value,
726 addend, ELF_STUB_DIRECT,
727 loc0, targetsec);
728 } else {
729 /* Ok, we can reach it directly. */
730 val = sym->st_value;
731 val += addend;
732 }
733 } else {
734 val = sym->st_value;
735 if (strncmp(strtab + sym->st_name, "$$", 2)
736 == 0)
737 val = get_stub(me, val, addend, ELF_STUB_MILLI,
738 loc0, targetsec);
739 else
740 val = get_stub(me, val, addend, ELF_STUB_GOT,
741 loc0, targetsec);
742 }
743 pr_debug("STUB FOR %s loc %px, val %llx+%llx at %llx\n",
744 strtab + sym->st_name, loc, sym->st_value,
745 addend, val);
746 val = (val - dot - 8)/4;
747 CHECK_RELOC(val, 22);
748 *loc = (*loc & ~0x3ff1ffd) | reassemble_22(val);
749 break;
750 case R_PARISC_PCREL32:
751 /* 32-bit PC relative address */
752 *loc = val - dot - 8 + addend;
753 break;
754 case R_PARISC_PCREL64:
755 /* 64-bit PC relative address */
756 *loc64 = val - dot - 8 + addend;
757 break;
758 case R_PARISC_DIR64:
759 /* 64-bit effective address */
760 *loc64 = val + addend;
761 break;
762 case R_PARISC_SEGREL32:
763 /* 32-bit segment relative address */
764 /* See note about special handling of SEGREL32 at
765 * the beginning of this file.
766 */
767 *loc = fsel(val, addend);
768 break;
769 case R_PARISC_SECREL32:
770 /* 32-bit section relative address. */
771 *loc = fsel(val, addend);
772 break;
773 case R_PARISC_FPTR64:
774 /* 64-bit function address */
775 if (within_module(val + addend, me)) {
776 *loc64 = get_fdesc(me, val+addend);
777 pr_debug("FDESC for %s at %llx points to %llx\n",
778 strtab + sym->st_name, *loc64,
779 ((Elf_Fdesc *)*loc64)->addr);
780 } else {
781 /* if the symbol is not local to this
782 * module then val+addend is a pointer
783 * to the function descriptor */
784 pr_debug("Non local FPTR64 Symbol %s loc %p val %llx\n",
785 strtab + sym->st_name,
786 loc, val);
787 *loc64 = val + addend;
788 }
789 break;
790
791 default:
792 printk(KERN_ERR "module %s: Unknown relocation: %Lu\n",
793 me->name, ELF64_R_TYPE(rel[i].r_info));
794 return -ENOEXEC;
795 }
796 }
797 return 0;
798 }
799 #endif
800
801 static void
register_unwind_table(struct module * me,const Elf_Shdr * sechdrs)802 register_unwind_table(struct module *me,
803 const Elf_Shdr *sechdrs)
804 {
805 unsigned char *table, *end;
806 unsigned long gp;
807
808 if (!me->arch.unwind_section)
809 return;
810
811 table = (unsigned char *)sechdrs[me->arch.unwind_section].sh_addr;
812 end = table + sechdrs[me->arch.unwind_section].sh_size;
813 gp = (Elf_Addr)me->mem[MOD_TEXT].base + me->arch.got_offset;
814
815 pr_debug("register_unwind_table(), sect = %d at 0x%p - 0x%p (gp=0x%lx)\n",
816 me->arch.unwind_section, table, end, gp);
817 me->arch.unwind = unwind_table_add(me->name, 0, gp, table, end);
818 }
819
820 static void
deregister_unwind_table(struct module * me)821 deregister_unwind_table(struct module *me)
822 {
823 if (me->arch.unwind)
824 unwind_table_remove(me->arch.unwind);
825 }
826
module_finalize(const Elf_Ehdr * hdr,const Elf_Shdr * sechdrs,struct module * me)827 int module_finalize(const Elf_Ehdr *hdr,
828 const Elf_Shdr *sechdrs,
829 struct module *me)
830 {
831 int i;
832 unsigned long nsyms;
833 const char *strtab = NULL;
834 const Elf_Shdr *s;
835 char *secstrings;
836 int symindex __maybe_unused = -1;
837 Elf_Sym *newptr, *oldptr;
838 Elf_Shdr *symhdr = NULL;
839 #ifdef DEBUG
840 Elf_Fdesc *entry;
841 u32 *addr;
842
843 entry = (Elf_Fdesc *)me->init;
844 printk("FINALIZE, ->init FPTR is %p, GP %lx ADDR %lx\n", entry,
845 entry->gp, entry->addr);
846 addr = (u32 *)entry->addr;
847 printk("INSNS: %x %x %x %x\n",
848 addr[0], addr[1], addr[2], addr[3]);
849 printk("got entries used %ld, gots max %ld\n"
850 "fdescs used %ld, fdescs max %ld\n",
851 me->arch.got_count, me->arch.got_max,
852 me->arch.fdesc_count, me->arch.fdesc_max);
853 #endif
854
855 register_unwind_table(me, sechdrs);
856
857 /* haven't filled in me->symtab yet, so have to find it
858 * ourselves */
859 for (i = 1; i < hdr->e_shnum; i++) {
860 if(sechdrs[i].sh_type == SHT_SYMTAB
861 && (sechdrs[i].sh_flags & SHF_ALLOC)) {
862 int strindex = sechdrs[i].sh_link;
863 symindex = i;
864 /* FIXME: AWFUL HACK
865 * The cast is to drop the const from
866 * the sechdrs pointer */
867 symhdr = (Elf_Shdr *)&sechdrs[i];
868 strtab = (char *)sechdrs[strindex].sh_addr;
869 break;
870 }
871 }
872
873 pr_debug("module %s: strtab %p, symhdr %p\n",
874 me->name, strtab, symhdr);
875
876 if(me->arch.got_count > MAX_GOTS) {
877 printk(KERN_ERR "%s: Global Offset Table overflow (used %ld, allowed %d)\n",
878 me->name, me->arch.got_count, MAX_GOTS);
879 return -EINVAL;
880 }
881
882 kfree(me->arch.section);
883 me->arch.section = NULL;
884
885 /* no symbol table */
886 if(symhdr == NULL)
887 return 0;
888
889 oldptr = (void *)symhdr->sh_addr;
890 newptr = oldptr + 1; /* we start counting at 1 */
891 nsyms = symhdr->sh_size / sizeof(Elf_Sym);
892 pr_debug("OLD num_symtab %lu\n", nsyms);
893
894 for (i = 1; i < nsyms; i++) {
895 oldptr++; /* note, count starts at 1 so preincrement */
896 if(strncmp(strtab + oldptr->st_name,
897 ".L", 2) == 0)
898 continue;
899
900 if(newptr != oldptr)
901 *newptr++ = *oldptr;
902 else
903 newptr++;
904
905 }
906 nsyms = newptr - (Elf_Sym *)symhdr->sh_addr;
907 pr_debug("NEW num_symtab %lu\n", nsyms);
908 symhdr->sh_size = nsyms * sizeof(Elf_Sym);
909
910 /* find .altinstructions section */
911 secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
912 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
913 void *aseg = (void *) s->sh_addr;
914 char *secname = secstrings + s->sh_name;
915
916 if (!strcmp(".altinstructions", secname))
917 /* patch .altinstructions */
918 apply_alternatives(aseg, aseg + s->sh_size, me->name);
919
920 #ifdef CONFIG_DYNAMIC_FTRACE
921 /* For 32 bit kernels we're compiling modules with
922 * -ffunction-sections so we must relocate the addresses in the
923 * ftrace callsite section.
924 */
925 if (symindex != -1 && !strcmp(secname, FTRACE_CALLSITE_SECTION)) {
926 int err;
927 if (s->sh_type == SHT_REL)
928 err = apply_relocate((Elf_Shdr *)sechdrs,
929 strtab, symindex,
930 s - sechdrs, me);
931 else if (s->sh_type == SHT_RELA)
932 err = apply_relocate_add((Elf_Shdr *)sechdrs,
933 strtab, symindex,
934 s - sechdrs, me);
935 if (err)
936 return err;
937 }
938 #endif
939 }
940 return 0;
941 }
942
module_arch_cleanup(struct module * mod)943 void module_arch_cleanup(struct module *mod)
944 {
945 deregister_unwind_table(mod);
946 }
947
948 #ifdef CONFIG_64BIT
dereference_module_function_descriptor(struct module * mod,void * ptr)949 void *dereference_module_function_descriptor(struct module *mod, void *ptr)
950 {
951 unsigned long start_opd = (Elf64_Addr)mod->mem[MOD_TEXT].base +
952 mod->arch.fdesc_offset;
953 unsigned long end_opd = start_opd +
954 mod->arch.fdesc_count * sizeof(Elf64_Fdesc);
955
956 if (ptr < (void *)start_opd || ptr >= (void *)end_opd)
957 return ptr;
958
959 return dereference_function_descriptor(ptr);
960 }
961 #endif
962