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