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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Kernel module help for PPC64.
3 Copyright (C) 2001, 2003 Rusty Russell IBM Corporation.
4
5*/
6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/module.h>
10#include <linux/elf.h>
11#include <linux/moduleloader.h>
12#include <linux/err.h>
13#include <linux/vmalloc.h>
14#include <linux/ftrace.h>
15#include <linux/bug.h>
16#include <linux/uaccess.h>
17#include <asm/module.h>
18#include <asm/firmware.h>
19#include <asm/code-patching.h>
20#include <linux/sort.h>
21#include <asm/setup.h>
22#include <asm/sections.h>
23#include <asm/inst.h>
24
25/* FIXME: We don't do .init separately. To do this, we'd need to have
26 a separate r2 value in the init and core section, and stub between
27 them, too.
28
29 Using a magic allocator which places modules within 32MB solves
30 this, and makes other things simpler. Anton?
31 --RR. */
32
33#ifdef PPC64_ELF_ABI_v2
34
35/* An address is simply the address of the function. */
36typedef unsigned long func_desc_t;
37
38static func_desc_t func_desc(unsigned long addr)
39{
40 return addr;
41}
42static unsigned long func_addr(unsigned long addr)
43{
44 return addr;
45}
46static unsigned long stub_func_addr(func_desc_t func)
47{
48 return func;
49}
50
51/* PowerPC64 specific values for the Elf64_Sym st_other field. */
52#define STO_PPC64_LOCAL_BIT 5
53#define STO_PPC64_LOCAL_MASK (7 << STO_PPC64_LOCAL_BIT)
54#define PPC64_LOCAL_ENTRY_OFFSET(other) \
55 (((1 << (((other) & STO_PPC64_LOCAL_MASK) >> STO_PPC64_LOCAL_BIT)) >> 2) << 2)
56
57static unsigned int local_entry_offset(const Elf64_Sym *sym)
58{
59 /* sym->st_other indicates offset to local entry point
60 * (otherwise it will assume r12 is the address of the start
61 * of function and try to derive r2 from it). */
62 return PPC64_LOCAL_ENTRY_OFFSET(sym->st_other);
63}
64#else
65
66/* An address is address of the OPD entry, which contains address of fn. */
67typedef struct ppc64_opd_entry func_desc_t;
68
69static func_desc_t func_desc(unsigned long addr)
70{
71 return *(struct ppc64_opd_entry *)addr;
72}
73static unsigned long func_addr(unsigned long addr)
74{
75 return func_desc(addr).funcaddr;
76}
77static unsigned long stub_func_addr(func_desc_t func)
78{
79 return func.funcaddr;
80}
81static unsigned int local_entry_offset(const Elf64_Sym *sym)
82{
83 return 0;
84}
85
86void *dereference_module_function_descriptor(struct module *mod, void *ptr)
87{
88 if (ptr < (void *)mod->arch.start_opd ||
89 ptr >= (void *)mod->arch.end_opd)
90 return ptr;
91
92 return dereference_function_descriptor(ptr);
93}
94#endif
95
96#define STUB_MAGIC 0x73747562 /* stub */
97
98/* Like PPC32, we need little trampolines to do > 24-bit jumps (into
99 the kernel itself). But on PPC64, these need to be used for every
100 jump, actually, to reset r2 (TOC+0x8000). */
101struct ppc64_stub_entry
102{
103 /* 28 byte jump instruction sequence (7 instructions). We only
104 * need 6 instructions on ABIv2 but we always allocate 7 so
105 * so we don't have to modify the trampoline load instruction. */
106 u32 jump[7];
107 /* Used by ftrace to identify stubs */
108 u32 magic;
109 /* Data for the above code */
110 func_desc_t funcdata;
111};
112
113/*
114 * PPC64 uses 24 bit jumps, but we need to jump into other modules or
115 * the kernel which may be further. So we jump to a stub.
116 *
117 * For ELFv1 we need to use this to set up the new r2 value (aka TOC
118 * pointer). For ELFv2 it's the callee's responsibility to set up the
119 * new r2, but for both we need to save the old r2.
120 *
121 * We could simply patch the new r2 value and function pointer into
122 * the stub, but it's significantly shorter to put these values at the
123 * end of the stub code, and patch the stub address (32-bits relative
124 * to the TOC ptr, r2) into the stub.
125 *
126 * addis r11,r2, <high>
127 * addi r11,r11, <low>
128 * std r2,R2_STACK_OFFSET(r1)
129 * ld r12,32(r11)
130 * ld r2,40(r11)
131 * mtctr r12
132 * bctr
133 */
134static u32 ppc64_stub_insns[] = {
135 PPC_INST_ADDIS | __PPC_RT(R11) | __PPC_RA(R2),
136 PPC_INST_ADDI | __PPC_RT(R11) | __PPC_RA(R11),
137 /* Save current r2 value in magic place on the stack. */
138 PPC_INST_STD | __PPC_RS(R2) | __PPC_RA(R1) | R2_STACK_OFFSET,
139 PPC_INST_LD | __PPC_RT(R12) | __PPC_RA(R11) | 32,
140#ifdef PPC64_ELF_ABI_v1
141 /* Set up new r2 from function descriptor */
142 PPC_INST_LD | __PPC_RT(R2) | __PPC_RA(R11) | 40,
143#endif
144 PPC_INST_MTCTR | __PPC_RS(R12),
145 PPC_INST_BCTR,
146};
147
148/* Count how many different 24-bit relocations (different symbol,
149 different addend) */
150static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num)
151{
152 unsigned int i, r_info, r_addend, _count_relocs;
153
154 /* FIXME: Only count external ones --RR */
155 _count_relocs = 0;
156 r_info = 0;
157 r_addend = 0;
158 for (i = 0; i < num; i++)
159 /* Only count 24-bit relocs, others don't need stubs */
160 if (ELF64_R_TYPE(rela[i].r_info) == R_PPC_REL24 &&
161 (r_info != ELF64_R_SYM(rela[i].r_info) ||
162 r_addend != rela[i].r_addend)) {
163 _count_relocs++;
164 r_info = ELF64_R_SYM(rela[i].r_info);
165 r_addend = rela[i].r_addend;
166 }
167
168 return _count_relocs;
169}
170
171static int relacmp(const void *_x, const void *_y)
172{
173 const Elf64_Rela *x, *y;
174
175 y = (Elf64_Rela *)_x;
176 x = (Elf64_Rela *)_y;
177
178 /* Compare the entire r_info (as opposed to ELF64_R_SYM(r_info) only) to
179 * make the comparison cheaper/faster. It won't affect the sorting or
180 * the counting algorithms' performance
181 */
182 if (x->r_info < y->r_info)
183 return -1;
184 else if (x->r_info > y->r_info)
185 return 1;
186 else if (x->r_addend < y->r_addend)
187 return -1;
188 else if (x->r_addend > y->r_addend)
189 return 1;
190 else
191 return 0;
192}
193
194/* Get size of potential trampolines required. */
195static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
196 const Elf64_Shdr *sechdrs)
197{
198 /* One extra reloc so it's always 0-funcaddr terminated */
199 unsigned long relocs = 1;
200 unsigned i;
201
202 /* Every relocated section... */
203 for (i = 1; i < hdr->e_shnum; i++) {
204 if (sechdrs[i].sh_type == SHT_RELA) {
205 pr_debug("Found relocations in section %u\n", i);
206 pr_debug("Ptr: %p. Number: %Lu\n",
207 (void *)sechdrs[i].sh_addr,
208 sechdrs[i].sh_size / sizeof(Elf64_Rela));
209
210 /* Sort the relocation information based on a symbol and
211 * addend key. This is a stable O(n*log n) complexity
212 * alogrithm but it will reduce the complexity of
213 * count_relocs() to linear complexity O(n)
214 */
215 sort((void *)sechdrs[i].sh_addr,
216 sechdrs[i].sh_size / sizeof(Elf64_Rela),
217 sizeof(Elf64_Rela), relacmp, NULL);
218
219 relocs += count_relocs((void *)sechdrs[i].sh_addr,
220 sechdrs[i].sh_size
221 / sizeof(Elf64_Rela));
222 }
223 }
224
225#ifdef CONFIG_DYNAMIC_FTRACE
226 /* make the trampoline to the ftrace_caller */
227 relocs++;
228#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
229 /* an additional one for ftrace_regs_caller */
230 relocs++;
231#endif
232#endif
233
234 pr_debug("Looks like a total of %lu stubs, max\n", relocs);
235 return relocs * sizeof(struct ppc64_stub_entry);
236}
237
238/* Still needed for ELFv2, for .TOC. */
239static void dedotify_versions(struct modversion_info *vers,
240 unsigned long size)
241{
242 struct modversion_info *end;
243
244 for (end = (void *)vers + size; vers < end; vers++)
245 if (vers->name[0] == '.') {
246 memmove(vers->name, vers->name+1, strlen(vers->name));
247 }
248}
249
250/*
251 * Undefined symbols which refer to .funcname, hack to funcname. Make .TOC.
252 * seem to be defined (value set later).
253 */
254static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab)
255{
256 unsigned int i;
257
258 for (i = 1; i < numsyms; i++) {
259 if (syms[i].st_shndx == SHN_UNDEF) {
260 char *name = strtab + syms[i].st_name;
261 if (name[0] == '.') {
262 if (strcmp(name+1, "TOC.") == 0)
263 syms[i].st_shndx = SHN_ABS;
264 syms[i].st_name++;
265 }
266 }
267 }
268}
269
270static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs,
271 const char *strtab,
272 unsigned int symindex)
273{
274 unsigned int i, numsyms;
275 Elf64_Sym *syms;
276
277 syms = (Elf64_Sym *)sechdrs[symindex].sh_addr;
278 numsyms = sechdrs[symindex].sh_size / sizeof(Elf64_Sym);
279
280 for (i = 1; i < numsyms; i++) {
281 if (syms[i].st_shndx == SHN_ABS
282 && strcmp(strtab + syms[i].st_name, "TOC.") == 0)
283 return &syms[i];
284 }
285 return NULL;
286}
287
288int module_frob_arch_sections(Elf64_Ehdr *hdr,
289 Elf64_Shdr *sechdrs,
290 char *secstrings,
291 struct module *me)
292{
293 unsigned int i;
294
295 /* Find .toc and .stubs sections, symtab and strtab */
296 for (i = 1; i < hdr->e_shnum; i++) {
297 char *p;
298 if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0)
299 me->arch.stubs_section = i;
300 else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0) {
301 me->arch.toc_section = i;
302 if (sechdrs[i].sh_addralign < 8)
303 sechdrs[i].sh_addralign = 8;
304 }
305 else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0)
306 dedotify_versions((void *)hdr + sechdrs[i].sh_offset,
307 sechdrs[i].sh_size);
308
309 /* We don't handle .init for the moment: rename to _init */
310 while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init")))
311 p[0] = '_';
312
313 if (sechdrs[i].sh_type == SHT_SYMTAB)
314 dedotify((void *)hdr + sechdrs[i].sh_offset,
315 sechdrs[i].sh_size / sizeof(Elf64_Sym),
316 (void *)hdr
317 + sechdrs[sechdrs[i].sh_link].sh_offset);
318 }
319
320 if (!me->arch.stubs_section) {
321 pr_err("%s: doesn't contain .stubs.\n", me->name);
322 return -ENOEXEC;
323 }
324
325 /* If we don't have a .toc, just use .stubs. We need to set r2
326 to some reasonable value in case the module calls out to
327 other functions via a stub, or if a function pointer escapes
328 the module by some means. */
329 if (!me->arch.toc_section)
330 me->arch.toc_section = me->arch.stubs_section;
331
332 /* Override the stubs size */
333 sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs);
334 return 0;
335}
336
337#ifdef CONFIG_MPROFILE_KERNEL
338
339#define PACATOC offsetof(struct paca_struct, kernel_toc)
340
341/*
342 * ld r12,PACATOC(r13)
343 * addis r12,r12,<high>
344 * addi r12,r12,<low>
345 * mtctr r12
346 * bctr
347 */
348static u32 stub_insns[] = {
349 PPC_INST_LD | __PPC_RT(R12) | __PPC_RA(R13) | PACATOC,
350 PPC_INST_ADDIS | __PPC_RT(R12) | __PPC_RA(R12),
351 PPC_INST_ADDI | __PPC_RT(R12) | __PPC_RA(R12),
352 PPC_INST_MTCTR | __PPC_RS(R12),
353 PPC_INST_BCTR,
354};
355
356/*
357 * For mprofile-kernel we use a special stub for ftrace_caller() because we
358 * can't rely on r2 containing this module's TOC when we enter the stub.
359 *
360 * That can happen if the function calling us didn't need to use the toc. In
361 * that case it won't have setup r2, and the r2 value will be either the
362 * kernel's toc, or possibly another modules toc.
363 *
364 * To deal with that this stub uses the kernel toc, which is always accessible
365 * via the paca (in r13). The target (ftrace_caller()) is responsible for
366 * saving and restoring the toc before returning.
367 */
368static inline int create_ftrace_stub(struct ppc64_stub_entry *entry,
369 unsigned long addr,
370 struct module *me)
371{
372 long reladdr;
373
374 memcpy(entry->jump, stub_insns, sizeof(stub_insns));
375
376 /* Stub uses address relative to kernel toc (from the paca) */
377 reladdr = addr - kernel_toc_addr();
378 if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
379 pr_err("%s: Address of %ps out of range of kernel_toc.\n",
380 me->name, (void *)addr);
381 return 0;
382 }
383
384 entry->jump[1] |= PPC_HA(reladdr);
385 entry->jump[2] |= PPC_LO(reladdr);
386
387 /* Eventhough we don't use funcdata in the stub, it's needed elsewhere. */
388 entry->funcdata = func_desc(addr);
389 entry->magic = STUB_MAGIC;
390
391 return 1;
392}
393
394static bool is_mprofile_ftrace_call(const char *name)
395{
396 if (!strcmp("_mcount", name))
397 return true;
398#ifdef CONFIG_DYNAMIC_FTRACE
399 if (!strcmp("ftrace_caller", name))
400 return true;
401#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
402 if (!strcmp("ftrace_regs_caller", name))
403 return true;
404#endif
405#endif
406
407 return false;
408}
409#else
410static inline int create_ftrace_stub(struct ppc64_stub_entry *entry,
411 unsigned long addr,
412 struct module *me)
413{
414 return 0;
415}
416
417static bool is_mprofile_ftrace_call(const char *name)
418{
419 return false;
420}
421#endif
422
423/*
424 * r2 is the TOC pointer: it actually points 0x8000 into the TOC (this gives the
425 * value maximum span in an instruction which uses a signed offset). Round down
426 * to a 256 byte boundary for the odd case where we are setting up r2 without a
427 * .toc section.
428 */
429static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me)
430{
431 return (sechdrs[me->arch.toc_section].sh_addr & ~0xfful) + 0x8000;
432}
433
434/* Patch stub to reference function and correct r2 value. */
435static inline int create_stub(const Elf64_Shdr *sechdrs,
436 struct ppc64_stub_entry *entry,
437 unsigned long addr,
438 struct module *me,
439 const char *name)
440{
441 long reladdr;
442
443 if (is_mprofile_ftrace_call(name))
444 return create_ftrace_stub(entry, addr, me);
445
446 memcpy(entry->jump, ppc64_stub_insns, sizeof(ppc64_stub_insns));
447
448 /* Stub uses address relative to r2. */
449 reladdr = (unsigned long)entry - my_r2(sechdrs, me);
450 if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
451 pr_err("%s: Address %p of stub out of range of %p.\n",
452 me->name, (void *)reladdr, (void *)my_r2);
453 return 0;
454 }
455 pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr);
456
457 entry->jump[0] |= PPC_HA(reladdr);
458 entry->jump[1] |= PPC_LO(reladdr);
459 entry->funcdata = func_desc(addr);
460 entry->magic = STUB_MAGIC;
461
462 return 1;
463}
464
465/* Create stub to jump to function described in this OPD/ptr: we need the
466 stub to set up the TOC ptr (r2) for the function. */
467static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs,
468 unsigned long addr,
469 struct module *me,
470 const char *name)
471{
472 struct ppc64_stub_entry *stubs;
473 unsigned int i, num_stubs;
474
475 num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs);
476
477 /* Find this stub, or if that fails, the next avail. entry */
478 stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr;
479 for (i = 0; stub_func_addr(stubs[i].funcdata); i++) {
480 if (WARN_ON(i >= num_stubs))
481 return 0;
482
483 if (stub_func_addr(stubs[i].funcdata) == func_addr(addr))
484 return (unsigned long)&stubs[i];
485 }
486
487 if (!create_stub(sechdrs, &stubs[i], addr, me, name))
488 return 0;
489
490 return (unsigned long)&stubs[i];
491}
492
493/* We expect a noop next: if it is, replace it with instruction to
494 restore r2. */
495static int restore_r2(const char *name, u32 *instruction, struct module *me)
496{
497 u32 *prev_insn = instruction - 1;
498
499 if (is_mprofile_ftrace_call(name))
500 return 1;
501
502 /*
503 * Make sure the branch isn't a sibling call. Sibling calls aren't
504 * "link" branches and they don't return, so they don't need the r2
505 * restore afterwards.
506 */
507 if (!instr_is_relative_link_branch(ppc_inst(*prev_insn)))
508 return 1;
509
510 if (*instruction != PPC_INST_NOP) {
511 pr_err("%s: Expected nop after call, got %08x at %pS\n",
512 me->name, *instruction, instruction);
513 return 0;
514 }
515 /* ld r2,R2_STACK_OFFSET(r1) */
516 *instruction = PPC_INST_LD_TOC;
517 return 1;
518}
519
520int apply_relocate_add(Elf64_Shdr *sechdrs,
521 const char *strtab,
522 unsigned int symindex,
523 unsigned int relsec,
524 struct module *me)
525{
526 unsigned int i;
527 Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr;
528 Elf64_Sym *sym;
529 unsigned long *location;
530 unsigned long value;
531
532 pr_debug("Applying ADD relocate section %u to %u\n", relsec,
533 sechdrs[relsec].sh_info);
534
535 /* First time we're called, we can fix up .TOC. */
536 if (!me->arch.toc_fixed) {
537 sym = find_dot_toc(sechdrs, strtab, symindex);
538 /* It's theoretically possible that a module doesn't want a
539 * .TOC. so don't fail it just for that. */
540 if (sym)
541 sym->st_value = my_r2(sechdrs, me);
542 me->arch.toc_fixed = true;
543 }
544
545 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
546 /* This is where to make the change */
547 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
548 + rela[i].r_offset;
549 /* This is the symbol it is referring to */
550 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
551 + ELF64_R_SYM(rela[i].r_info);
552
553 pr_debug("RELOC at %p: %li-type as %s (0x%lx) + %li\n",
554 location, (long)ELF64_R_TYPE(rela[i].r_info),
555 strtab + sym->st_name, (unsigned long)sym->st_value,
556 (long)rela[i].r_addend);
557
558 /* `Everything is relative'. */
559 value = sym->st_value + rela[i].r_addend;
560
561 switch (ELF64_R_TYPE(rela[i].r_info)) {
562 case R_PPC64_ADDR32:
563 /* Simply set it */
564 *(u32 *)location = value;
565 break;
566
567 case R_PPC64_ADDR64:
568 /* Simply set it */
569 *(unsigned long *)location = value;
570 break;
571
572 case R_PPC64_TOC:
573 *(unsigned long *)location = my_r2(sechdrs, me);
574 break;
575
576 case R_PPC64_TOC16:
577 /* Subtract TOC pointer */
578 value -= my_r2(sechdrs, me);
579 if (value + 0x8000 > 0xffff) {
580 pr_err("%s: bad TOC16 relocation (0x%lx)\n",
581 me->name, value);
582 return -ENOEXEC;
583 }
584 *((uint16_t *) location)
585 = (*((uint16_t *) location) & ~0xffff)
586 | (value & 0xffff);
587 break;
588
589 case R_PPC64_TOC16_LO:
590 /* Subtract TOC pointer */
591 value -= my_r2(sechdrs, me);
592 *((uint16_t *) location)
593 = (*((uint16_t *) location) & ~0xffff)
594 | (value & 0xffff);
595 break;
596
597 case R_PPC64_TOC16_DS:
598 /* Subtract TOC pointer */
599 value -= my_r2(sechdrs, me);
600 if ((value & 3) != 0 || value + 0x8000 > 0xffff) {
601 pr_err("%s: bad TOC16_DS relocation (0x%lx)\n",
602 me->name, value);
603 return -ENOEXEC;
604 }
605 *((uint16_t *) location)
606 = (*((uint16_t *) location) & ~0xfffc)
607 | (value & 0xfffc);
608 break;
609
610 case R_PPC64_TOC16_LO_DS:
611 /* Subtract TOC pointer */
612 value -= my_r2(sechdrs, me);
613 if ((value & 3) != 0) {
614 pr_err("%s: bad TOC16_LO_DS relocation (0x%lx)\n",
615 me->name, value);
616 return -ENOEXEC;
617 }
618 *((uint16_t *) location)
619 = (*((uint16_t *) location) & ~0xfffc)
620 | (value & 0xfffc);
621 break;
622
623 case R_PPC64_TOC16_HA:
624 /* Subtract TOC pointer */
625 value -= my_r2(sechdrs, me);
626 value = ((value + 0x8000) >> 16);
627 *((uint16_t *) location)
628 = (*((uint16_t *) location) & ~0xffff)
629 | (value & 0xffff);
630 break;
631
632 case R_PPC_REL24:
633 /* FIXME: Handle weak symbols here --RR */
634 if (sym->st_shndx == SHN_UNDEF ||
635 sym->st_shndx == SHN_LIVEPATCH) {
636 /* External: go via stub */
637 value = stub_for_addr(sechdrs, value, me,
638 strtab + sym->st_name);
639 if (!value)
640 return -ENOENT;
641 if (!restore_r2(strtab + sym->st_name,
642 (u32 *)location + 1, me))
643 return -ENOEXEC;
644 } else
645 value += local_entry_offset(sym);
646
647 /* Convert value to relative */
648 value -= (unsigned long)location;
649 if (value + 0x2000000 > 0x3ffffff || (value & 3) != 0){
650 pr_err("%s: REL24 %li out of range!\n",
651 me->name, (long int)value);
652 return -ENOEXEC;
653 }
654
655 /* Only replace bits 2 through 26 */
656 *(uint32_t *)location
657 = (*(uint32_t *)location & ~0x03fffffc)
658 | (value & 0x03fffffc);
659 break;
660
661 case R_PPC64_REL64:
662 /* 64 bits relative (used by features fixups) */
663 *location = value - (unsigned long)location;
664 break;
665
666 case R_PPC64_REL32:
667 /* 32 bits relative (used by relative exception tables) */
668 /* Convert value to relative */
669 value -= (unsigned long)location;
670 if (value + 0x80000000 > 0xffffffff) {
671 pr_err("%s: REL32 %li out of range!\n",
672 me->name, (long int)value);
673 return -ENOEXEC;
674 }
675 *(u32 *)location = value;
676 break;
677
678 case R_PPC64_TOCSAVE:
679 /*
680 * Marker reloc indicates we don't have to save r2.
681 * That would only save us one instruction, so ignore
682 * it.
683 */
684 break;
685
686 case R_PPC64_ENTRY:
687 /*
688 * Optimize ELFv2 large code model entry point if
689 * the TOC is within 2GB range of current location.
690 */
691 value = my_r2(sechdrs, me) - (unsigned long)location;
692 if (value + 0x80008000 > 0xffffffff)
693 break;
694 /*
695 * Check for the large code model prolog sequence:
696 * ld r2, ...(r12)
697 * add r2, r2, r12
698 */
699 if ((((uint32_t *)location)[0] & ~0xfffc) !=
700 (PPC_INST_LD | __PPC_RT(R2) | __PPC_RA(R12)))
701 break;
702 if (((uint32_t *)location)[1] !=
703 (PPC_INST_ADD | __PPC_RT(R2) | __PPC_RA(R2) | __PPC_RB(R12)))
704 break;
705 /*
706 * If found, replace it with:
707 * addis r2, r12, (.TOC.-func)@ha
708 * addi r2, r2, (.TOC.-func)@l
709 */
710 ((uint32_t *)location)[0] = PPC_INST_ADDIS | __PPC_RT(R2) |
711 __PPC_RA(R12) | PPC_HA(value);
712 ((uint32_t *)location)[1] = PPC_INST_ADDI | __PPC_RT(R2) |
713 __PPC_RA(R2) | PPC_LO(value);
714 break;
715
716 case R_PPC64_REL16_HA:
717 /* Subtract location pointer */
718 value -= (unsigned long)location;
719 value = ((value + 0x8000) >> 16);
720 *((uint16_t *) location)
721 = (*((uint16_t *) location) & ~0xffff)
722 | (value & 0xffff);
723 break;
724
725 case R_PPC64_REL16_LO:
726 /* Subtract location pointer */
727 value -= (unsigned long)location;
728 *((uint16_t *) location)
729 = (*((uint16_t *) location) & ~0xffff)
730 | (value & 0xffff);
731 break;
732
733 default:
734 pr_err("%s: Unknown ADD relocation: %lu\n",
735 me->name,
736 (unsigned long)ELF64_R_TYPE(rela[i].r_info));
737 return -ENOEXEC;
738 }
739 }
740
741 return 0;
742}
743
744#ifdef CONFIG_DYNAMIC_FTRACE
745int module_trampoline_target(struct module *mod, unsigned long addr,
746 unsigned long *target)
747{
748 struct ppc64_stub_entry *stub;
749 func_desc_t funcdata;
750 u32 magic;
751
752 if (!within_module_core(addr, mod)) {
753 pr_err("%s: stub %lx not in module %s\n", __func__, addr, mod->name);
754 return -EFAULT;
755 }
756
757 stub = (struct ppc64_stub_entry *)addr;
758
759 if (copy_from_kernel_nofault(&magic, &stub->magic,
760 sizeof(magic))) {
761 pr_err("%s: fault reading magic for stub %lx for %s\n", __func__, addr, mod->name);
762 return -EFAULT;
763 }
764
765 if (magic != STUB_MAGIC) {
766 pr_err("%s: bad magic for stub %lx for %s\n", __func__, addr, mod->name);
767 return -EFAULT;
768 }
769
770 if (copy_from_kernel_nofault(&funcdata, &stub->funcdata,
771 sizeof(funcdata))) {
772 pr_err("%s: fault reading funcdata for stub %lx for %s\n", __func__, addr, mod->name);
773 return -EFAULT;
774 }
775
776 *target = stub_func_addr(funcdata);
777
778 return 0;
779}
780
781int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs)
782{
783 mod->arch.tramp = stub_for_addr(sechdrs,
784 (unsigned long)ftrace_caller,
785 mod,
786 "ftrace_caller");
787#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
788 mod->arch.tramp_regs = stub_for_addr(sechdrs,
789 (unsigned long)ftrace_regs_caller,
790 mod,
791 "ftrace_regs_caller");
792 if (!mod->arch.tramp_regs)
793 return -ENOENT;
794#endif
795
796 if (!mod->arch.tramp)
797 return -ENOENT;
798
799 return 0;
800}
801#endif
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Kernel module help for PPC64.
3 Copyright (C) 2001, 2003 Rusty Russell IBM Corporation.
4
5*/
6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/module.h>
10#include <linux/elf.h>
11#include <linux/moduleloader.h>
12#include <linux/err.h>
13#include <linux/vmalloc.h>
14#include <linux/ftrace.h>
15#include <linux/bug.h>
16#include <linux/uaccess.h>
17#include <linux/kernel.h>
18#include <asm/module.h>
19#include <asm/firmware.h>
20#include <asm/code-patching.h>
21#include <linux/sort.h>
22#include <asm/setup.h>
23#include <asm/sections.h>
24#include <asm/inst.h>
25
26/* FIXME: We don't do .init separately. To do this, we'd need to have
27 a separate r2 value in the init and core section, and stub between
28 them, too.
29
30 Using a magic allocator which places modules within 32MB solves
31 this, and makes other things simpler. Anton?
32 --RR. */
33
34bool module_elf_check_arch(Elf_Ehdr *hdr)
35{
36 unsigned long abi_level = hdr->e_flags & 0x3;
37
38 if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2))
39 return abi_level == 2;
40 else
41 return abi_level < 2;
42}
43
44#ifdef CONFIG_PPC64_ELF_ABI_V2
45
46static func_desc_t func_desc(unsigned long addr)
47{
48 func_desc_t desc = {
49 .addr = addr,
50 };
51
52 return desc;
53}
54
55/* PowerPC64 specific values for the Elf64_Sym st_other field. */
56#define STO_PPC64_LOCAL_BIT 5
57#define STO_PPC64_LOCAL_MASK (7 << STO_PPC64_LOCAL_BIT)
58#define PPC64_LOCAL_ENTRY_OFFSET(other) \
59 (((1 << (((other) & STO_PPC64_LOCAL_MASK) >> STO_PPC64_LOCAL_BIT)) >> 2) << 2)
60
61static unsigned int local_entry_offset(const Elf64_Sym *sym)
62{
63 /* sym->st_other indicates offset to local entry point
64 * (otherwise it will assume r12 is the address of the start
65 * of function and try to derive r2 from it). */
66 return PPC64_LOCAL_ENTRY_OFFSET(sym->st_other);
67}
68#else
69
70static func_desc_t func_desc(unsigned long addr)
71{
72 return *(struct func_desc *)addr;
73}
74static unsigned int local_entry_offset(const Elf64_Sym *sym)
75{
76 return 0;
77}
78
79void *dereference_module_function_descriptor(struct module *mod, void *ptr)
80{
81 if (ptr < (void *)mod->arch.start_opd ||
82 ptr >= (void *)mod->arch.end_opd)
83 return ptr;
84
85 return dereference_function_descriptor(ptr);
86}
87#endif
88
89static unsigned long func_addr(unsigned long addr)
90{
91 return func_desc(addr).addr;
92}
93
94static unsigned long stub_func_addr(func_desc_t func)
95{
96 return func.addr;
97}
98
99#define STUB_MAGIC 0x73747562 /* stub */
100
101/* Like PPC32, we need little trampolines to do > 24-bit jumps (into
102 the kernel itself). But on PPC64, these need to be used for every
103 jump, actually, to reset r2 (TOC+0x8000). */
104struct ppc64_stub_entry
105{
106 /* 28 byte jump instruction sequence (7 instructions). We only
107 * need 6 instructions on ABIv2 but we always allocate 7 so
108 * so we don't have to modify the trampoline load instruction. */
109 u32 jump[7];
110 /* Used by ftrace to identify stubs */
111 u32 magic;
112 /* Data for the above code */
113 func_desc_t funcdata;
114};
115
116/*
117 * PPC64 uses 24 bit jumps, but we need to jump into other modules or
118 * the kernel which may be further. So we jump to a stub.
119 *
120 * For ELFv1 we need to use this to set up the new r2 value (aka TOC
121 * pointer). For ELFv2 it's the callee's responsibility to set up the
122 * new r2, but for both we need to save the old r2.
123 *
124 * We could simply patch the new r2 value and function pointer into
125 * the stub, but it's significantly shorter to put these values at the
126 * end of the stub code, and patch the stub address (32-bits relative
127 * to the TOC ptr, r2) into the stub.
128 */
129static u32 ppc64_stub_insns[] = {
130 PPC_RAW_ADDIS(_R11, _R2, 0),
131 PPC_RAW_ADDI(_R11, _R11, 0),
132 /* Save current r2 value in magic place on the stack. */
133 PPC_RAW_STD(_R2, _R1, R2_STACK_OFFSET),
134 PPC_RAW_LD(_R12, _R11, 32),
135#ifdef CONFIG_PPC64_ELF_ABI_V1
136 /* Set up new r2 from function descriptor */
137 PPC_RAW_LD(_R2, _R11, 40),
138#endif
139 PPC_RAW_MTCTR(_R12),
140 PPC_RAW_BCTR(),
141};
142
143/* Count how many different 24-bit relocations (different symbol,
144 different addend) */
145static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num)
146{
147 unsigned int i, r_info, r_addend, _count_relocs;
148
149 /* FIXME: Only count external ones --RR */
150 _count_relocs = 0;
151 r_info = 0;
152 r_addend = 0;
153 for (i = 0; i < num; i++)
154 /* Only count 24-bit relocs, others don't need stubs */
155 if (ELF64_R_TYPE(rela[i].r_info) == R_PPC_REL24 &&
156 (r_info != ELF64_R_SYM(rela[i].r_info) ||
157 r_addend != rela[i].r_addend)) {
158 _count_relocs++;
159 r_info = ELF64_R_SYM(rela[i].r_info);
160 r_addend = rela[i].r_addend;
161 }
162
163 return _count_relocs;
164}
165
166static int relacmp(const void *_x, const void *_y)
167{
168 const Elf64_Rela *x, *y;
169
170 y = (Elf64_Rela *)_x;
171 x = (Elf64_Rela *)_y;
172
173 /* Compare the entire r_info (as opposed to ELF64_R_SYM(r_info) only) to
174 * make the comparison cheaper/faster. It won't affect the sorting or
175 * the counting algorithms' performance
176 */
177 if (x->r_info < y->r_info)
178 return -1;
179 else if (x->r_info > y->r_info)
180 return 1;
181 else if (x->r_addend < y->r_addend)
182 return -1;
183 else if (x->r_addend > y->r_addend)
184 return 1;
185 else
186 return 0;
187}
188
189/* Get size of potential trampolines required. */
190static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
191 const Elf64_Shdr *sechdrs)
192{
193 /* One extra reloc so it's always 0-addr terminated */
194 unsigned long relocs = 1;
195 unsigned i;
196
197 /* Every relocated section... */
198 for (i = 1; i < hdr->e_shnum; i++) {
199 if (sechdrs[i].sh_type == SHT_RELA) {
200 pr_debug("Found relocations in section %u\n", i);
201 pr_debug("Ptr: %p. Number: %Lu\n",
202 (void *)sechdrs[i].sh_addr,
203 sechdrs[i].sh_size / sizeof(Elf64_Rela));
204
205 /* Sort the relocation information based on a symbol and
206 * addend key. This is a stable O(n*log n) complexity
207 * algorithm but it will reduce the complexity of
208 * count_relocs() to linear complexity O(n)
209 */
210 sort((void *)sechdrs[i].sh_addr,
211 sechdrs[i].sh_size / sizeof(Elf64_Rela),
212 sizeof(Elf64_Rela), relacmp, NULL);
213
214 relocs += count_relocs((void *)sechdrs[i].sh_addr,
215 sechdrs[i].sh_size
216 / sizeof(Elf64_Rela));
217 }
218 }
219
220#ifdef CONFIG_DYNAMIC_FTRACE
221 /* make the trampoline to the ftrace_caller */
222 relocs++;
223#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
224 /* an additional one for ftrace_regs_caller */
225 relocs++;
226#endif
227#endif
228
229 pr_debug("Looks like a total of %lu stubs, max\n", relocs);
230 return relocs * sizeof(struct ppc64_stub_entry);
231}
232
233/* Still needed for ELFv2, for .TOC. */
234static void dedotify_versions(struct modversion_info *vers,
235 unsigned long size)
236{
237 struct modversion_info *end;
238
239 for (end = (void *)vers + size; vers < end; vers++)
240 if (vers->name[0] == '.') {
241 memmove(vers->name, vers->name+1, strlen(vers->name));
242 }
243}
244
245/*
246 * Undefined symbols which refer to .funcname, hack to funcname. Make .TOC.
247 * seem to be defined (value set later).
248 */
249static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab)
250{
251 unsigned int i;
252
253 for (i = 1; i < numsyms; i++) {
254 if (syms[i].st_shndx == SHN_UNDEF) {
255 char *name = strtab + syms[i].st_name;
256 if (name[0] == '.') {
257 if (strcmp(name+1, "TOC.") == 0)
258 syms[i].st_shndx = SHN_ABS;
259 syms[i].st_name++;
260 }
261 }
262 }
263}
264
265static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs,
266 const char *strtab,
267 unsigned int symindex)
268{
269 unsigned int i, numsyms;
270 Elf64_Sym *syms;
271
272 syms = (Elf64_Sym *)sechdrs[symindex].sh_addr;
273 numsyms = sechdrs[symindex].sh_size / sizeof(Elf64_Sym);
274
275 for (i = 1; i < numsyms; i++) {
276 if (syms[i].st_shndx == SHN_ABS
277 && strcmp(strtab + syms[i].st_name, "TOC.") == 0)
278 return &syms[i];
279 }
280 return NULL;
281}
282
283bool module_init_section(const char *name)
284{
285 /* We don't handle .init for the moment: always return false. */
286 return false;
287}
288
289int module_frob_arch_sections(Elf64_Ehdr *hdr,
290 Elf64_Shdr *sechdrs,
291 char *secstrings,
292 struct module *me)
293{
294 unsigned int i;
295
296 /* Find .toc and .stubs sections, symtab and strtab */
297 for (i = 1; i < hdr->e_shnum; i++) {
298 if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0)
299 me->arch.stubs_section = i;
300 else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0) {
301 me->arch.toc_section = i;
302 if (sechdrs[i].sh_addralign < 8)
303 sechdrs[i].sh_addralign = 8;
304 }
305 else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0)
306 dedotify_versions((void *)hdr + sechdrs[i].sh_offset,
307 sechdrs[i].sh_size);
308
309 if (sechdrs[i].sh_type == SHT_SYMTAB)
310 dedotify((void *)hdr + sechdrs[i].sh_offset,
311 sechdrs[i].sh_size / sizeof(Elf64_Sym),
312 (void *)hdr
313 + sechdrs[sechdrs[i].sh_link].sh_offset);
314 }
315
316 if (!me->arch.stubs_section) {
317 pr_err("%s: doesn't contain .stubs.\n", me->name);
318 return -ENOEXEC;
319 }
320
321 /* If we don't have a .toc, just use .stubs. We need to set r2
322 to some reasonable value in case the module calls out to
323 other functions via a stub, or if a function pointer escapes
324 the module by some means. */
325 if (!me->arch.toc_section)
326 me->arch.toc_section = me->arch.stubs_section;
327
328 /* Override the stubs size */
329 sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs);
330 return 0;
331}
332
333#ifdef CONFIG_MPROFILE_KERNEL
334
335static u32 stub_insns[] = {
336 PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernel_toc)),
337 PPC_RAW_ADDIS(_R12, _R12, 0),
338 PPC_RAW_ADDI(_R12, _R12, 0),
339 PPC_RAW_MTCTR(_R12),
340 PPC_RAW_BCTR(),
341};
342
343/*
344 * For mprofile-kernel we use a special stub for ftrace_caller() because we
345 * can't rely on r2 containing this module's TOC when we enter the stub.
346 *
347 * That can happen if the function calling us didn't need to use the toc. In
348 * that case it won't have setup r2, and the r2 value will be either the
349 * kernel's toc, or possibly another modules toc.
350 *
351 * To deal with that this stub uses the kernel toc, which is always accessible
352 * via the paca (in r13). The target (ftrace_caller()) is responsible for
353 * saving and restoring the toc before returning.
354 */
355static inline int create_ftrace_stub(struct ppc64_stub_entry *entry,
356 unsigned long addr,
357 struct module *me)
358{
359 long reladdr;
360
361 memcpy(entry->jump, stub_insns, sizeof(stub_insns));
362
363 /* Stub uses address relative to kernel toc (from the paca) */
364 reladdr = addr - kernel_toc_addr();
365 if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
366 pr_err("%s: Address of %ps out of range of kernel_toc.\n",
367 me->name, (void *)addr);
368 return 0;
369 }
370
371 entry->jump[1] |= PPC_HA(reladdr);
372 entry->jump[2] |= PPC_LO(reladdr);
373
374 /* Even though we don't use funcdata in the stub, it's needed elsewhere. */
375 entry->funcdata = func_desc(addr);
376 entry->magic = STUB_MAGIC;
377
378 return 1;
379}
380
381static bool is_mprofile_ftrace_call(const char *name)
382{
383 if (!strcmp("_mcount", name))
384 return true;
385#ifdef CONFIG_DYNAMIC_FTRACE
386 if (!strcmp("ftrace_caller", name))
387 return true;
388#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
389 if (!strcmp("ftrace_regs_caller", name))
390 return true;
391#endif
392#endif
393
394 return false;
395}
396#else
397static inline int create_ftrace_stub(struct ppc64_stub_entry *entry,
398 unsigned long addr,
399 struct module *me)
400{
401 return 0;
402}
403
404static bool is_mprofile_ftrace_call(const char *name)
405{
406 return false;
407}
408#endif
409
410/*
411 * r2 is the TOC pointer: it actually points 0x8000 into the TOC (this gives the
412 * value maximum span in an instruction which uses a signed offset). Round down
413 * to a 256 byte boundary for the odd case where we are setting up r2 without a
414 * .toc section.
415 */
416static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me)
417{
418 return (sechdrs[me->arch.toc_section].sh_addr & ~0xfful) + 0x8000;
419}
420
421/* Patch stub to reference function and correct r2 value. */
422static inline int create_stub(const Elf64_Shdr *sechdrs,
423 struct ppc64_stub_entry *entry,
424 unsigned long addr,
425 struct module *me,
426 const char *name)
427{
428 long reladdr;
429 func_desc_t desc;
430 int i;
431
432 if (is_mprofile_ftrace_call(name))
433 return create_ftrace_stub(entry, addr, me);
434
435 for (i = 0; i < ARRAY_SIZE(ppc64_stub_insns); i++) {
436 if (patch_instruction(&entry->jump[i],
437 ppc_inst(ppc64_stub_insns[i])))
438 return 0;
439 }
440
441 /* Stub uses address relative to r2. */
442 reladdr = (unsigned long)entry - my_r2(sechdrs, me);
443 if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
444 pr_err("%s: Address %p of stub out of range of %p.\n",
445 me->name, (void *)reladdr, (void *)my_r2);
446 return 0;
447 }
448 pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr);
449
450 if (patch_instruction(&entry->jump[0],
451 ppc_inst(entry->jump[0] | PPC_HA(reladdr))))
452 return 0;
453
454 if (patch_instruction(&entry->jump[1],
455 ppc_inst(entry->jump[1] | PPC_LO(reladdr))))
456 return 0;
457
458 // func_desc_t is 8 bytes if ABIv2, else 16 bytes
459 desc = func_desc(addr);
460 for (i = 0; i < sizeof(func_desc_t) / sizeof(u32); i++) {
461 if (patch_instruction(((u32 *)&entry->funcdata) + i,
462 ppc_inst(((u32 *)(&desc))[i])))
463 return 0;
464 }
465
466 if (patch_instruction(&entry->magic, ppc_inst(STUB_MAGIC)))
467 return 0;
468
469 return 1;
470}
471
472/* Create stub to jump to function described in this OPD/ptr: we need the
473 stub to set up the TOC ptr (r2) for the function. */
474static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs,
475 unsigned long addr,
476 struct module *me,
477 const char *name)
478{
479 struct ppc64_stub_entry *stubs;
480 unsigned int i, num_stubs;
481
482 num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs);
483
484 /* Find this stub, or if that fails, the next avail. entry */
485 stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr;
486 for (i = 0; stub_func_addr(stubs[i].funcdata); i++) {
487 if (WARN_ON(i >= num_stubs))
488 return 0;
489
490 if (stub_func_addr(stubs[i].funcdata) == func_addr(addr))
491 return (unsigned long)&stubs[i];
492 }
493
494 if (!create_stub(sechdrs, &stubs[i], addr, me, name))
495 return 0;
496
497 return (unsigned long)&stubs[i];
498}
499
500/* We expect a noop next: if it is, replace it with instruction to
501 restore r2. */
502static int restore_r2(const char *name, u32 *instruction, struct module *me)
503{
504 u32 *prev_insn = instruction - 1;
505
506 if (is_mprofile_ftrace_call(name))
507 return 1;
508
509 /*
510 * Make sure the branch isn't a sibling call. Sibling calls aren't
511 * "link" branches and they don't return, so they don't need the r2
512 * restore afterwards.
513 */
514 if (!instr_is_relative_link_branch(ppc_inst(*prev_insn)))
515 return 1;
516
517 if (*instruction != PPC_RAW_NOP()) {
518 pr_err("%s: Expected nop after call, got %08x at %pS\n",
519 me->name, *instruction, instruction);
520 return 0;
521 }
522
523 /* ld r2,R2_STACK_OFFSET(r1) */
524 if (patch_instruction(instruction, ppc_inst(PPC_INST_LD_TOC)))
525 return 0;
526
527 return 1;
528}
529
530int apply_relocate_add(Elf64_Shdr *sechdrs,
531 const char *strtab,
532 unsigned int symindex,
533 unsigned int relsec,
534 struct module *me)
535{
536 unsigned int i;
537 Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr;
538 Elf64_Sym *sym;
539 unsigned long *location;
540 unsigned long value;
541
542 pr_debug("Applying ADD relocate section %u to %u\n", relsec,
543 sechdrs[relsec].sh_info);
544
545 /* First time we're called, we can fix up .TOC. */
546 if (!me->arch.toc_fixed) {
547 sym = find_dot_toc(sechdrs, strtab, symindex);
548 /* It's theoretically possible that a module doesn't want a
549 * .TOC. so don't fail it just for that. */
550 if (sym)
551 sym->st_value = my_r2(sechdrs, me);
552 me->arch.toc_fixed = true;
553 }
554
555 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
556 /* This is where to make the change */
557 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
558 + rela[i].r_offset;
559 /* This is the symbol it is referring to */
560 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
561 + ELF64_R_SYM(rela[i].r_info);
562
563 pr_debug("RELOC at %p: %li-type as %s (0x%lx) + %li\n",
564 location, (long)ELF64_R_TYPE(rela[i].r_info),
565 strtab + sym->st_name, (unsigned long)sym->st_value,
566 (long)rela[i].r_addend);
567
568 /* `Everything is relative'. */
569 value = sym->st_value + rela[i].r_addend;
570
571 switch (ELF64_R_TYPE(rela[i].r_info)) {
572 case R_PPC64_ADDR32:
573 /* Simply set it */
574 *(u32 *)location = value;
575 break;
576
577 case R_PPC64_ADDR64:
578 /* Simply set it */
579 *(unsigned long *)location = value;
580 break;
581
582 case R_PPC64_TOC:
583 *(unsigned long *)location = my_r2(sechdrs, me);
584 break;
585
586 case R_PPC64_TOC16:
587 /* Subtract TOC pointer */
588 value -= my_r2(sechdrs, me);
589 if (value + 0x8000 > 0xffff) {
590 pr_err("%s: bad TOC16 relocation (0x%lx)\n",
591 me->name, value);
592 return -ENOEXEC;
593 }
594 *((uint16_t *) location)
595 = (*((uint16_t *) location) & ~0xffff)
596 | (value & 0xffff);
597 break;
598
599 case R_PPC64_TOC16_LO:
600 /* Subtract TOC pointer */
601 value -= my_r2(sechdrs, me);
602 *((uint16_t *) location)
603 = (*((uint16_t *) location) & ~0xffff)
604 | (value & 0xffff);
605 break;
606
607 case R_PPC64_TOC16_DS:
608 /* Subtract TOC pointer */
609 value -= my_r2(sechdrs, me);
610 if ((value & 3) != 0 || value + 0x8000 > 0xffff) {
611 pr_err("%s: bad TOC16_DS relocation (0x%lx)\n",
612 me->name, value);
613 return -ENOEXEC;
614 }
615 *((uint16_t *) location)
616 = (*((uint16_t *) location) & ~0xfffc)
617 | (value & 0xfffc);
618 break;
619
620 case R_PPC64_TOC16_LO_DS:
621 /* Subtract TOC pointer */
622 value -= my_r2(sechdrs, me);
623 if ((value & 3) != 0) {
624 pr_err("%s: bad TOC16_LO_DS relocation (0x%lx)\n",
625 me->name, value);
626 return -ENOEXEC;
627 }
628 *((uint16_t *) location)
629 = (*((uint16_t *) location) & ~0xfffc)
630 | (value & 0xfffc);
631 break;
632
633 case R_PPC64_TOC16_HA:
634 /* Subtract TOC pointer */
635 value -= my_r2(sechdrs, me);
636 value = ((value + 0x8000) >> 16);
637 *((uint16_t *) location)
638 = (*((uint16_t *) location) & ~0xffff)
639 | (value & 0xffff);
640 break;
641
642 case R_PPC_REL24:
643 /* FIXME: Handle weak symbols here --RR */
644 if (sym->st_shndx == SHN_UNDEF ||
645 sym->st_shndx == SHN_LIVEPATCH) {
646 /* External: go via stub */
647 value = stub_for_addr(sechdrs, value, me,
648 strtab + sym->st_name);
649 if (!value)
650 return -ENOENT;
651 if (!restore_r2(strtab + sym->st_name,
652 (u32 *)location + 1, me))
653 return -ENOEXEC;
654 } else
655 value += local_entry_offset(sym);
656
657 /* Convert value to relative */
658 value -= (unsigned long)location;
659 if (value + 0x2000000 > 0x3ffffff || (value & 3) != 0){
660 pr_err("%s: REL24 %li out of range!\n",
661 me->name, (long int)value);
662 return -ENOEXEC;
663 }
664
665 /* Only replace bits 2 through 26 */
666 value = (*(uint32_t *)location & ~PPC_LI_MASK) | PPC_LI(value);
667
668 if (patch_instruction((u32 *)location, ppc_inst(value)))
669 return -EFAULT;
670
671 break;
672
673 case R_PPC64_REL64:
674 /* 64 bits relative (used by features fixups) */
675 *location = value - (unsigned long)location;
676 break;
677
678 case R_PPC64_REL32:
679 /* 32 bits relative (used by relative exception tables) */
680 /* Convert value to relative */
681 value -= (unsigned long)location;
682 if (value + 0x80000000 > 0xffffffff) {
683 pr_err("%s: REL32 %li out of range!\n",
684 me->name, (long int)value);
685 return -ENOEXEC;
686 }
687 *(u32 *)location = value;
688 break;
689
690 case R_PPC64_TOCSAVE:
691 /*
692 * Marker reloc indicates we don't have to save r2.
693 * That would only save us one instruction, so ignore
694 * it.
695 */
696 break;
697
698 case R_PPC64_ENTRY:
699 /*
700 * Optimize ELFv2 large code model entry point if
701 * the TOC is within 2GB range of current location.
702 */
703 value = my_r2(sechdrs, me) - (unsigned long)location;
704 if (value + 0x80008000 > 0xffffffff)
705 break;
706 /*
707 * Check for the large code model prolog sequence:
708 * ld r2, ...(r12)
709 * add r2, r2, r12
710 */
711 if ((((uint32_t *)location)[0] & ~0xfffc) != PPC_RAW_LD(_R2, _R12, 0))
712 break;
713 if (((uint32_t *)location)[1] != PPC_RAW_ADD(_R2, _R2, _R12))
714 break;
715 /*
716 * If found, replace it with:
717 * addis r2, r12, (.TOC.-func)@ha
718 * addi r2, r2, (.TOC.-func)@l
719 */
720 ((uint32_t *)location)[0] = PPC_RAW_ADDIS(_R2, _R12, PPC_HA(value));
721 ((uint32_t *)location)[1] = PPC_RAW_ADDI(_R2, _R2, PPC_LO(value));
722 break;
723
724 case R_PPC64_REL16_HA:
725 /* Subtract location pointer */
726 value -= (unsigned long)location;
727 value = ((value + 0x8000) >> 16);
728 *((uint16_t *) location)
729 = (*((uint16_t *) location) & ~0xffff)
730 | (value & 0xffff);
731 break;
732
733 case R_PPC64_REL16_LO:
734 /* Subtract location pointer */
735 value -= (unsigned long)location;
736 *((uint16_t *) location)
737 = (*((uint16_t *) location) & ~0xffff)
738 | (value & 0xffff);
739 break;
740
741 default:
742 pr_err("%s: Unknown ADD relocation: %lu\n",
743 me->name,
744 (unsigned long)ELF64_R_TYPE(rela[i].r_info));
745 return -ENOEXEC;
746 }
747 }
748
749 return 0;
750}
751
752#ifdef CONFIG_DYNAMIC_FTRACE
753int module_trampoline_target(struct module *mod, unsigned long addr,
754 unsigned long *target)
755{
756 struct ppc64_stub_entry *stub;
757 func_desc_t funcdata;
758 u32 magic;
759
760 if (!within_module_core(addr, mod)) {
761 pr_err("%s: stub %lx not in module %s\n", __func__, addr, mod->name);
762 return -EFAULT;
763 }
764
765 stub = (struct ppc64_stub_entry *)addr;
766
767 if (copy_from_kernel_nofault(&magic, &stub->magic,
768 sizeof(magic))) {
769 pr_err("%s: fault reading magic for stub %lx for %s\n", __func__, addr, mod->name);
770 return -EFAULT;
771 }
772
773 if (magic != STUB_MAGIC) {
774 pr_err("%s: bad magic for stub %lx for %s\n", __func__, addr, mod->name);
775 return -EFAULT;
776 }
777
778 if (copy_from_kernel_nofault(&funcdata, &stub->funcdata,
779 sizeof(funcdata))) {
780 pr_err("%s: fault reading funcdata for stub %lx for %s\n", __func__, addr, mod->name);
781 return -EFAULT;
782 }
783
784 *target = stub_func_addr(funcdata);
785
786 return 0;
787}
788
789int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs)
790{
791 mod->arch.tramp = stub_for_addr(sechdrs,
792 (unsigned long)ftrace_caller,
793 mod,
794 "ftrace_caller");
795#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
796 mod->arch.tramp_regs = stub_for_addr(sechdrs,
797 (unsigned long)ftrace_regs_caller,
798 mod,
799 "ftrace_regs_caller");
800 if (!mod->arch.tramp_regs)
801 return -ENOENT;
802#endif
803
804 if (!mod->arch.tramp)
805 return -ENOENT;
806
807 return 0;
808}
809#endif