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Merge tag 'trace-printf-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace...
[drm/drm-misc.git] / arch / powerpc / kernel / module_64.c
blob45dac7b46aa3cdcb2058a2320b88c0d67e5586b3
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/text-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
34 bool 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
46 static 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
61 static 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
70 static func_desc_t func_desc(unsigned long addr)
71 {
72 return *(struct func_desc *)addr;
73 }
74 static unsigned int local_entry_offset(const Elf64_Sym *sym)
75 {
76 return 0;
77 }
78
79 void *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
89 static unsigned long func_addr(unsigned long addr)
90 {
91 return func_desc(addr).addr;
92 }
93
94 static 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). */
104 struct ppc64_stub_entry {
105 /*
106 * 28 byte jump instruction sequence (7 instructions) that can
107 * hold ppc64_stub_insns or stub_insns. Must be 8-byte aligned
108 * with PCREL kernels that use prefix instructions in the stub.
109 */
110 u32 jump[7];
111 /* Used by ftrace to identify stubs */
112 u32 magic;
113 /* Data for the above code */
114 func_desc_t funcdata;
115 } __aligned(8);
116
117 struct ppc64_got_entry {
118 u64 addr;
119 };
120
121 /*
122 * PPC64 uses 24 bit jumps, but we need to jump into other modules or
123 * the kernel which may be further. So we jump to a stub.
124 *
125 * Target address and TOC are loaded from function descriptor in the
126 * ppc64_stub_entry.
127 *
128 * r12 is used to generate the target address, which is required for the
129 * ELFv2 global entry point calling convention.
130 *
131 * TOC handling:
132 * - PCREL does not have a TOC.
133 * - ELFv2 non-PCREL just has to save r2, the callee is responsible for
134 * setting its own TOC pointer at the global entry address.
135 * - ELFv1 must load the new TOC pointer from the function descriptor.
136 */
137 static u32 ppc64_stub_insns[] = {
138 #ifdef CONFIG_PPC_KERNEL_PCREL
139 /* pld r12,addr */
140 PPC_PREFIX_8LS | __PPC_PRFX_R(1),
141 PPC_INST_PLD | ___PPC_RT(_R12),
142 #else
143 PPC_RAW_ADDIS(_R11, _R2, 0),
144 PPC_RAW_ADDI(_R11, _R11, 0),
145 /* Save current r2 value in magic place on the stack. */
146 PPC_RAW_STD(_R2, _R1, R2_STACK_OFFSET),
147 PPC_RAW_LD(_R12, _R11, 32),
148 #ifdef CONFIG_PPC64_ELF_ABI_V1
149 /* Set up new r2 from function descriptor */
150 PPC_RAW_LD(_R2, _R11, 40),
151 #endif
152 #endif
153 PPC_RAW_MTCTR(_R12),
154 PPC_RAW_BCTR(),
155 };
156
157 /*
158 * Count how many different r_type relocations (different symbol,
159 * different addend).
160 */
161 static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num,
162 unsigned long r_type)
163 {
164 unsigned int i, r_info, r_addend, _count_relocs;
165
166 /* FIXME: Only count external ones --RR */
167 _count_relocs = 0;
168 r_info = 0;
169 r_addend = 0;
170 for (i = 0; i < num; i++)
171 /* Only count r_type relocs, others don't need stubs */
172 if (ELF64_R_TYPE(rela[i].r_info) == r_type &&
173 (r_info != ELF64_R_SYM(rela[i].r_info) ||
174 r_addend != rela[i].r_addend)) {
175 _count_relocs++;
176 r_info = ELF64_R_SYM(rela[i].r_info);
177 r_addend = rela[i].r_addend;
178 }
179
180 return _count_relocs;
181 }
182
183 static int relacmp(const void *_x, const void *_y)
184 {
185 const Elf64_Rela *x, *y;
186
187 y = (Elf64_Rela *)_x;
188 x = (Elf64_Rela *)_y;
189
190 /* Compare the entire r_info (as opposed to ELF64_R_SYM(r_info) only) to
191 * make the comparison cheaper/faster. It won't affect the sorting or
192 * the counting algorithms' performance
193 */
194 if (x->r_info < y->r_info)
195 return -1;
196 else if (x->r_info > y->r_info)
197 return 1;
198 else if (x->r_addend < y->r_addend)
199 return -1;
200 else if (x->r_addend > y->r_addend)
201 return 1;
202 else
203 return 0;
204 }
205
206 /* Get size of potential trampolines required. */
207 static unsigned long get_stubs_size(const Elf64_Ehdr *hdr,
208 const Elf64_Shdr *sechdrs,
209 char *secstrings,
210 struct module *me)
211 {
212 /* One extra reloc so it's always 0-addr terminated */
213 unsigned long relocs = 1;
214 unsigned i;
215
216 /* Every relocated section... */
217 for (i = 1; i < hdr->e_shnum; i++) {
218 if (sechdrs[i].sh_type == SHT_RELA) {
219 pr_debug("Found relocations in section %u\n", i);
220 pr_debug("Ptr: %p. Number: %Lu\n",
221 (void *)sechdrs[i].sh_addr,
222 sechdrs[i].sh_size / sizeof(Elf64_Rela));
223
224 /* Sort the relocation information based on a symbol and
225 * addend key. This is a stable O(n*log n) complexity
226 * algorithm but it will reduce the complexity of
227 * count_relocs() to linear complexity O(n)
228 */
229 sort((void *)sechdrs[i].sh_addr,
230 sechdrs[i].sh_size / sizeof(Elf64_Rela),
231 sizeof(Elf64_Rela), relacmp, NULL);
232
233 relocs += count_relocs((void *)sechdrs[i].sh_addr,
234 sechdrs[i].sh_size
235 / sizeof(Elf64_Rela),
236 R_PPC_REL24);
237 #ifdef CONFIG_PPC_KERNEL_PCREL
238 relocs += count_relocs((void *)sechdrs[i].sh_addr,
239 sechdrs[i].sh_size
240 / sizeof(Elf64_Rela),
241 R_PPC64_REL24_NOTOC);
242 #endif
243 }
244 }
245
246 /* stubs for ftrace_caller and ftrace_regs_caller */
247 relocs += IS_ENABLED(CONFIG_DYNAMIC_FTRACE) + IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS);
248
249 #ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
250 /* stubs for the function tracer */
251 for (i = 1; i < hdr->e_shnum; i++) {
252 if (!strcmp(secstrings + sechdrs[i].sh_name, "__patchable_function_entries")) {
253 me->arch.ool_stub_count = sechdrs[i].sh_size / sizeof(unsigned long);
254 me->arch.ool_stub_index = 0;
255 relocs += roundup(me->arch.ool_stub_count * sizeof(struct ftrace_ool_stub),
256 sizeof(struct ppc64_stub_entry)) /
257 sizeof(struct ppc64_stub_entry);
258 break;
259 }
260 }
261 if (i == hdr->e_shnum) {
262 pr_err("%s: doesn't contain __patchable_function_entries.\n", me->name);
263 return -ENOEXEC;
264 }
265 #endif
266
267 pr_debug("Looks like a total of %lu stubs, max\n", relocs);
268 return relocs * sizeof(struct ppc64_stub_entry);
269 }
270
271 #ifdef CONFIG_PPC_KERNEL_PCREL
272 static int count_pcpu_relocs(const Elf64_Shdr *sechdrs,
273 const Elf64_Rela *rela, unsigned int num,
274 unsigned int symindex, unsigned int pcpu)
275 {
276 unsigned int i, r_info, r_addend, _count_relocs;
277
278 _count_relocs = 0;
279 r_info = 0;
280 r_addend = 0;
281
282 for (i = 0; i < num; i++) {
283 Elf64_Sym *sym;
284
285 /* This is the symbol it is referring to */
286 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
287 + ELF64_R_SYM(rela[i].r_info);
288
289 if (sym->st_shndx == pcpu &&
290 (r_info != ELF64_R_SYM(rela[i].r_info) ||
291 r_addend != rela[i].r_addend)) {
292 _count_relocs++;
293 r_info = ELF64_R_SYM(rela[i].r_info);
294 r_addend = rela[i].r_addend;
295 }
296 }
297
298 return _count_relocs;
299 }
300
301 /* Get size of potential GOT required. */
302 static unsigned long get_got_size(const Elf64_Ehdr *hdr,
303 const Elf64_Shdr *sechdrs,
304 struct module *me)
305 {
306 /* One extra reloc so it's always 0-addr terminated */
307 unsigned long relocs = 1;
308 unsigned int i, symindex = 0;
309
310 for (i = 1; i < hdr->e_shnum; i++) {
311 if (sechdrs[i].sh_type == SHT_SYMTAB) {
312 symindex = i;
313 break;
314 }
315 }
316 WARN_ON_ONCE(!symindex);
317
318 /* Every relocated section... */
319 for (i = 1; i < hdr->e_shnum; i++) {
320 if (sechdrs[i].sh_type == SHT_RELA) {
321 pr_debug("Found relocations in section %u\n", i);
322 pr_debug("Ptr: %p. Number: %llu\n", (void *)sechdrs[i].sh_addr,
323 sechdrs[i].sh_size / sizeof(Elf64_Rela));
324
325 /*
326 * Sort the relocation information based on a symbol and
327 * addend key. This is a stable O(n*log n) complexity
328 * algorithm but it will reduce the complexity of
329 * count_relocs() to linear complexity O(n)
330 */
331 sort((void *)sechdrs[i].sh_addr,
332 sechdrs[i].sh_size / sizeof(Elf64_Rela),
333 sizeof(Elf64_Rela), relacmp, NULL);
334
335 relocs += count_relocs((void *)sechdrs[i].sh_addr,
336 sechdrs[i].sh_size
337 / sizeof(Elf64_Rela),
338 R_PPC64_GOT_PCREL34);
339
340 /*
341 * Percpu data access typically gets linked with
342 * REL34 relocations, but the percpu section gets
343 * moved at load time and requires that to be
344 * converted to GOT linkage.
345 */
346 if (IS_ENABLED(CONFIG_SMP) && symindex)
347 relocs += count_pcpu_relocs(sechdrs,
348 (void *)sechdrs[i].sh_addr,
349 sechdrs[i].sh_size
350 / sizeof(Elf64_Rela),
351 symindex, me->arch.pcpu_section);
352 }
353 }
354
355 pr_debug("Looks like a total of %lu GOT entries, max\n", relocs);
356 return relocs * sizeof(struct ppc64_got_entry);
357 }
358 #else /* CONFIG_PPC_KERNEL_PCREL */
359
360 /* Still needed for ELFv2, for .TOC. */
361 static void dedotify_versions(struct modversion_info *vers,
362 unsigned long size)
363 {
364 struct modversion_info *end;
365
366 for (end = (void *)vers + size; vers < end; vers++)
367 if (vers->name[0] == '.') {
368 memmove(vers->name, vers->name+1, strlen(vers->name));
369 }
370 }
371
372 /*
373 * Undefined symbols which refer to .funcname, hack to funcname. Make .TOC.
374 * seem to be defined (value set later).
375 */
376 static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab)
377 {
378 unsigned int i;
379
380 for (i = 1; i < numsyms; i++) {
381 if (syms[i].st_shndx == SHN_UNDEF) {
382 char *name = strtab + syms[i].st_name;
383 if (name[0] == '.') {
384 if (strcmp(name+1, "TOC.") == 0)
385 syms[i].st_shndx = SHN_ABS;
386 syms[i].st_name++;
387 }
388 }
389 }
390 }
391
392 static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs,
393 const char *strtab,
394 unsigned int symindex)
395 {
396 unsigned int i, numsyms;
397 Elf64_Sym *syms;
398
399 syms = (Elf64_Sym *)sechdrs[symindex].sh_addr;
400 numsyms = sechdrs[symindex].sh_size / sizeof(Elf64_Sym);
401
402 for (i = 1; i < numsyms; i++) {
403 if (syms[i].st_shndx == SHN_ABS
404 && strcmp(strtab + syms[i].st_name, "TOC.") == 0)
405 return &syms[i];
406 }
407 return NULL;
408 }
409 #endif /* CONFIG_PPC_KERNEL_PCREL */
410
411 bool module_init_section(const char *name)
412 {
413 /* We don't handle .init for the moment: always return false. */
414 return false;
415 }
416
417 int module_frob_arch_sections(Elf64_Ehdr *hdr,
418 Elf64_Shdr *sechdrs,
419 char *secstrings,
420 struct module *me)
421 {
422 unsigned int i;
423
424 /* Find .toc and .stubs sections, symtab and strtab */
425 for (i = 1; i < hdr->e_shnum; i++) {
426 if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0)
427 me->arch.stubs_section = i;
428 #ifdef CONFIG_PPC_KERNEL_PCREL
429 else if (strcmp(secstrings + sechdrs[i].sh_name, ".data..percpu") == 0)
430 me->arch.pcpu_section = i;
431 else if (strcmp(secstrings + sechdrs[i].sh_name, ".mygot") == 0) {
432 me->arch.got_section = i;
433 if (sechdrs[i].sh_addralign < 8)
434 sechdrs[i].sh_addralign = 8;
435 }
436 #else
437 else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0) {
438 me->arch.toc_section = i;
439 if (sechdrs[i].sh_addralign < 8)
440 sechdrs[i].sh_addralign = 8;
441 }
442 else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0)
443 dedotify_versions((void *)hdr + sechdrs[i].sh_offset,
444 sechdrs[i].sh_size);
445
446 if (sechdrs[i].sh_type == SHT_SYMTAB)
447 dedotify((void *)hdr + sechdrs[i].sh_offset,
448 sechdrs[i].sh_size / sizeof(Elf64_Sym),
449 (void *)hdr
450 + sechdrs[sechdrs[i].sh_link].sh_offset);
451 #endif
452 }
453
454 if (!me->arch.stubs_section) {
455 pr_err("%s: doesn't contain .stubs.\n", me->name);
456 return -ENOEXEC;
457 }
458
459 #ifdef CONFIG_PPC_KERNEL_PCREL
460 if (!me->arch.got_section) {
461 pr_err("%s: doesn't contain .mygot.\n", me->name);
462 return -ENOEXEC;
463 }
464
465 /* Override the got size */
466 sechdrs[me->arch.got_section].sh_size = get_got_size(hdr, sechdrs, me);
467 #else
468 /* If we don't have a .toc, just use .stubs. We need to set r2
469 to some reasonable value in case the module calls out to
470 other functions via a stub, or if a function pointer escapes
471 the module by some means. */
472 if (!me->arch.toc_section)
473 me->arch.toc_section = me->arch.stubs_section;
474 #endif
475
476 /* Override the stubs size */
477 sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs, secstrings, me);
478
479 return 0;
480 }
481
482 #if defined(CONFIG_MPROFILE_KERNEL) || defined(CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY)
483
484 static u32 stub_insns[] = {
485 #ifdef CONFIG_PPC_KERNEL_PCREL
486 PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernelbase)),
487 PPC_RAW_NOP(), /* align the prefix insn */
488 /* paddi r12,r12,addr */
489 PPC_PREFIX_MLS | __PPC_PRFX_R(0),
490 PPC_INST_PADDI | ___PPC_RT(_R12) | ___PPC_RA(_R12),
491 PPC_RAW_MTCTR(_R12),
492 PPC_RAW_BCTR(),
493 #else
494 PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernel_toc)),
495 PPC_RAW_ADDIS(_R12, _R12, 0),
496 PPC_RAW_ADDI(_R12, _R12, 0),
497 PPC_RAW_MTCTR(_R12),
498 PPC_RAW_BCTR(),
499 #endif
500 };
501
502 /*
503 * For mprofile-kernel we use a special stub for ftrace_caller() because we
504 * can't rely on r2 containing this module's TOC when we enter the stub.
505 *
506 * That can happen if the function calling us didn't need to use the toc. In
507 * that case it won't have setup r2, and the r2 value will be either the
508 * kernel's toc, or possibly another modules toc.
509 *
510 * To deal with that this stub uses the kernel toc, which is always accessible
511 * via the paca (in r13). The target (ftrace_caller()) is responsible for
512 * saving and restoring the toc before returning.
513 */
514 static inline int create_ftrace_stub(struct ppc64_stub_entry *entry,
515 unsigned long addr,
516 struct module *me)
517 {
518 long reladdr;
519
520 if ((unsigned long)entry->jump % 8 != 0) {
521 pr_err("%s: Address of stub entry is not 8-byte aligned\n", me->name);
522 return 0;
523 }
524
525 BUILD_BUG_ON(sizeof(stub_insns) > sizeof(entry->jump));
526 memcpy(entry->jump, stub_insns, sizeof(stub_insns));
527
528 if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) {
529 /* Stub uses address relative to kernel base (from the paca) */
530 reladdr = addr - local_paca->kernelbase;
531 if (reladdr > 0x1FFFFFFFFL || reladdr < -0x200000000L) {
532 pr_err("%s: Address of %ps out of range of 34-bit relative address.\n",
533 me->name, (void *)addr);
534 return 0;
535 }
536
537 entry->jump[2] |= IMM_H18(reladdr);
538 entry->jump[3] |= IMM_L(reladdr);
539 } else {
540 /* Stub uses address relative to kernel toc (from the paca) */
541 reladdr = addr - kernel_toc_addr();
542 if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
543 pr_err("%s: Address of %ps out of range of kernel_toc.\n",
544 me->name, (void *)addr);
545 return 0;
546 }
547
548 entry->jump[1] |= PPC_HA(reladdr);
549 entry->jump[2] |= PPC_LO(reladdr);
550 }
551
552 /* Even though we don't use funcdata in the stub, it's needed elsewhere. */
553 entry->funcdata = func_desc(addr);
554 entry->magic = STUB_MAGIC;
555
556 return 1;
557 }
558
559 static bool is_mprofile_ftrace_call(const char *name)
560 {
561 if (!strcmp("_mcount", name))
562 return true;
563 #ifdef CONFIG_DYNAMIC_FTRACE
564 if (!strcmp("ftrace_caller", name))
565 return true;
566 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
567 if (!strcmp("ftrace_regs_caller", name))
568 return true;
569 #endif
570 #endif
571
572 return false;
573 }
574 #else
575 static inline int create_ftrace_stub(struct ppc64_stub_entry *entry,
576 unsigned long addr,
577 struct module *me)
578 {
579 return 0;
580 }
581
582 static bool is_mprofile_ftrace_call(const char *name)
583 {
584 return false;
585 }
586 #endif
587
588 /*
589 * r2 is the TOC pointer: it actually points 0x8000 into the TOC (this gives the
590 * value maximum span in an instruction which uses a signed offset). Round down
591 * to a 256 byte boundary for the odd case where we are setting up r2 without a
592 * .toc section.
593 */
594 static inline unsigned long my_r2(const Elf64_Shdr *sechdrs, struct module *me)
595 {
596 #ifndef CONFIG_PPC_KERNEL_PCREL
597 return (sechdrs[me->arch.toc_section].sh_addr & ~0xfful) + 0x8000;
598 #else
599 return -1;
600 #endif
601 }
602
603 /* Patch stub to reference function and correct r2 value. */
604 static inline int create_stub(const Elf64_Shdr *sechdrs,
605 struct ppc64_stub_entry *entry,
606 unsigned long addr,
607 struct module *me,
608 const char *name)
609 {
610 long reladdr;
611 func_desc_t desc;
612 int i;
613
614 if (is_mprofile_ftrace_call(name))
615 return create_ftrace_stub(entry, addr, me);
616
617 if ((unsigned long)entry->jump % 8 != 0) {
618 pr_err("%s: Address of stub entry is not 8-byte aligned\n", me->name);
619 return 0;
620 }
621
622 BUILD_BUG_ON(sizeof(ppc64_stub_insns) > sizeof(entry->jump));
623 for (i = 0; i < ARRAY_SIZE(ppc64_stub_insns); i++) {
624 if (patch_instruction(&entry->jump[i],
625 ppc_inst(ppc64_stub_insns[i])))
626 return 0;
627 }
628
629 if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) {
630 /* Stub uses address relative to itself! */
631 reladdr = 0 + offsetof(struct ppc64_stub_entry, funcdata);
632 BUILD_BUG_ON(reladdr != 32);
633 if (reladdr > 0x1FFFFFFFFL || reladdr < -0x200000000L) {
634 pr_err("%s: Address of %p out of range of 34-bit relative address.\n",
635 me->name, (void *)reladdr);
636 return 0;
637 }
638 pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr);
639
640 /* May not even need this if we're relative to 0 */
641 if (patch_instruction(&entry->jump[0],
642 ppc_inst_prefix(entry->jump[0] | IMM_H18(reladdr),
643 entry->jump[1] | IMM_L(reladdr))))
644 return 0;
645
646 } else {
647 /* Stub uses address relative to r2. */
648 reladdr = (unsigned long)entry - my_r2(sechdrs, me);
649 if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {
650 pr_err("%s: Address %p of stub out of range of %p.\n",
651 me->name, (void *)reladdr, (void *)my_r2);
652 return 0;
653 }
654 pr_debug("Stub %p get data from reladdr %li\n", entry, reladdr);
655
656 if (patch_instruction(&entry->jump[0],
657 ppc_inst(entry->jump[0] | PPC_HA(reladdr))))
658 return 0;
659
660 if (patch_instruction(&entry->jump[1],
661 ppc_inst(entry->jump[1] | PPC_LO(reladdr))))
662 return 0;
663 }
664
665 // func_desc_t is 8 bytes if ABIv2, else 16 bytes
666 desc = func_desc(addr);
667 for (i = 0; i < sizeof(func_desc_t) / sizeof(u32); i++) {
668 if (patch_u32(((u32 *)&entry->funcdata) + i, ((u32 *)&desc)[i]))
669 return 0;
670 }
671
672 if (patch_u32(&entry->magic, STUB_MAGIC))
673 return 0;
674
675 return 1;
676 }
677
678 /* Create stub to jump to function described in this OPD/ptr: we need the
679 stub to set up the TOC ptr (r2) for the function. */
680 static unsigned long stub_for_addr(const Elf64_Shdr *sechdrs,
681 unsigned long addr,
682 struct module *me,
683 const char *name)
684 {
685 struct ppc64_stub_entry *stubs;
686 unsigned int i, num_stubs;
687
688 num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs);
689
690 /* Find this stub, or if that fails, the next avail. entry */
691 stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr;
692 for (i = 0; stub_func_addr(stubs[i].funcdata); i++) {
693 if (WARN_ON(i >= num_stubs))
694 return 0;
695
696 if (stub_func_addr(stubs[i].funcdata) == func_addr(addr))
697 return (unsigned long)&stubs[i];
698 }
699
700 if (!create_stub(sechdrs, &stubs[i], addr, me, name))
701 return 0;
702
703 return (unsigned long)&stubs[i];
704 }
705
706 #ifdef CONFIG_PPC_KERNEL_PCREL
707 /* Create GOT to load the location described in this ptr */
708 static unsigned long got_for_addr(const Elf64_Shdr *sechdrs,
709 unsigned long addr,
710 struct module *me,
711 const char *name)
712 {
713 struct ppc64_got_entry *got;
714 unsigned int i, num_got;
715
716 if (!IS_ENABLED(CONFIG_PPC_KERNEL_PCREL))
717 return addr;
718
719 num_got = sechdrs[me->arch.got_section].sh_size / sizeof(*got);
720
721 /* Find this stub, or if that fails, the next avail. entry */
722 got = (void *)sechdrs[me->arch.got_section].sh_addr;
723 for (i = 0; got[i].addr; i++) {
724 if (WARN_ON(i >= num_got))
725 return 0;
726
727 if (got[i].addr == addr)
728 return (unsigned long)&got[i];
729 }
730
731 got[i].addr = addr;
732
733 return (unsigned long)&got[i];
734 }
735 #endif
736
737 /* We expect a noop next: if it is, replace it with instruction to
738 restore r2. */
739 static int restore_r2(const char *name, u32 *instruction, struct module *me)
740 {
741 u32 *prev_insn = instruction - 1;
742 u32 insn_val = *instruction;
743
744 if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL))
745 return 0;
746
747 if (is_mprofile_ftrace_call(name))
748 return 0;
749
750 /*
751 * Make sure the branch isn't a sibling call. Sibling calls aren't
752 * "link" branches and they don't return, so they don't need the r2
753 * restore afterwards.
754 */
755 if (!instr_is_relative_link_branch(ppc_inst(*prev_insn)))
756 return 0;
757
758 /*
759 * For livepatch, the restore r2 instruction might have already been
760 * written previously, if the referenced symbol is in a previously
761 * unloaded module which is now being loaded again. In that case, skip
762 * the warning and the instruction write.
763 */
764 if (insn_val == PPC_INST_LD_TOC)
765 return 0;
766
767 if (insn_val != PPC_RAW_NOP()) {
768 pr_err("%s: Expected nop after call, got %08x at %pS\n",
769 me->name, insn_val, instruction);
770 return -ENOEXEC;
771 }
772
773 /* ld r2,R2_STACK_OFFSET(r1) */
774 return patch_instruction(instruction, ppc_inst(PPC_INST_LD_TOC));
775 }
776
777 int apply_relocate_add(Elf64_Shdr *sechdrs,
778 const char *strtab,
779 unsigned int symindex,
780 unsigned int relsec,
781 struct module *me)
782 {
783 unsigned int i;
784 Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr;
785 Elf64_Sym *sym;
786 unsigned long *location;
787 unsigned long value;
788
789 pr_debug("Applying ADD relocate section %u to %u\n", relsec,
790 sechdrs[relsec].sh_info);
791
792 #ifndef CONFIG_PPC_KERNEL_PCREL
793 /* First time we're called, we can fix up .TOC. */
794 if (!me->arch.toc_fixed) {
795 sym = find_dot_toc(sechdrs, strtab, symindex);
796 /* It's theoretically possible that a module doesn't want a
797 * .TOC. so don't fail it just for that. */
798 if (sym)
799 sym->st_value = my_r2(sechdrs, me);
800 me->arch.toc_fixed = true;
801 }
802 #endif
803 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
804 /* This is where to make the change */
805 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
806 + rela[i].r_offset;
807 /* This is the symbol it is referring to */
808 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
809 + ELF64_R_SYM(rela[i].r_info);
810
811 pr_debug("RELOC at %p: %li-type as %s (0x%lx) + %li\n",
812 location, (long)ELF64_R_TYPE(rela[i].r_info),
813 strtab + sym->st_name, (unsigned long)sym->st_value,
814 (long)rela[i].r_addend);
815
816 /* `Everything is relative'. */
817 value = sym->st_value + rela[i].r_addend;
818
819 switch (ELF64_R_TYPE(rela[i].r_info)) {
820 case R_PPC64_ADDR32:
821 /* Simply set it */
822 *(u32 *)location = value;
823 break;
824
825 case R_PPC64_ADDR64:
826 /* Simply set it */
827 *(unsigned long *)location = value;
828 break;
829
830 #ifndef CONFIG_PPC_KERNEL_PCREL
831 case R_PPC64_TOC:
832 *(unsigned long *)location = my_r2(sechdrs, me);
833 break;
834
835 case R_PPC64_TOC16:
836 /* Subtract TOC pointer */
837 value -= my_r2(sechdrs, me);
838 if (value + 0x8000 > 0xffff) {
839 pr_err("%s: bad TOC16 relocation (0x%lx)\n",
840 me->name, value);
841 return -ENOEXEC;
842 }
843 *((uint16_t *) location)
844 = (*((uint16_t *) location) & ~0xffff)
845 | (value & 0xffff);
846 break;
847
848 case R_PPC64_TOC16_LO:
849 /* Subtract TOC pointer */
850 value -= my_r2(sechdrs, me);
851 *((uint16_t *) location)
852 = (*((uint16_t *) location) & ~0xffff)
853 | (value & 0xffff);
854 break;
855
856 case R_PPC64_TOC16_DS:
857 /* Subtract TOC pointer */
858 value -= my_r2(sechdrs, me);
859 if ((value & 3) != 0 || value + 0x8000 > 0xffff) {
860 pr_err("%s: bad TOC16_DS relocation (0x%lx)\n",
861 me->name, value);
862 return -ENOEXEC;
863 }
864 *((uint16_t *) location)
865 = (*((uint16_t *) location) & ~0xfffc)
866 | (value & 0xfffc);
867 break;
868
869 case R_PPC64_TOC16_LO_DS:
870 /* Subtract TOC pointer */
871 value -= my_r2(sechdrs, me);
872 if ((value & 3) != 0) {
873 pr_err("%s: bad TOC16_LO_DS relocation (0x%lx)\n",
874 me->name, value);
875 return -ENOEXEC;
876 }
877 *((uint16_t *) location)
878 = (*((uint16_t *) location) & ~0xfffc)
879 | (value & 0xfffc);
880 break;
881
882 case R_PPC64_TOC16_HA:
883 /* Subtract TOC pointer */
884 value -= my_r2(sechdrs, me);
885 value = ((value + 0x8000) >> 16);
886 *((uint16_t *) location)
887 = (*((uint16_t *) location) & ~0xffff)
888 | (value & 0xffff);
889 break;
890 #endif
891
892 case R_PPC_REL24:
893 #ifdef CONFIG_PPC_KERNEL_PCREL
894 /* PCREL still generates REL24 for mcount */
895 case R_PPC64_REL24_NOTOC:
896 #endif
897 /* FIXME: Handle weak symbols here --RR */
898 if (sym->st_shndx == SHN_UNDEF ||
899 sym->st_shndx == SHN_LIVEPATCH) {
900 /* External: go via stub */
901 value = stub_for_addr(sechdrs, value, me,
902 strtab + sym->st_name);
903 if (!value)
904 return -ENOENT;
905 if (restore_r2(strtab + sym->st_name,
906 (u32 *)location + 1, me))
907 return -ENOEXEC;
908 } else
909 value += local_entry_offset(sym);
910
911 /* Convert value to relative */
912 value -= (unsigned long)location;
913 if (value + 0x2000000 > 0x3ffffff || (value & 3) != 0){
914 pr_err("%s: REL24 %li out of range!\n",
915 me->name, (long int)value);
916 return -ENOEXEC;
917 }
918
919 /* Only replace bits 2 through 26 */
920 value = (*(uint32_t *)location & ~PPC_LI_MASK) | PPC_LI(value);
921
922 if (patch_instruction((u32 *)location, ppc_inst(value)))
923 return -EFAULT;
924
925 break;
926
927 case R_PPC64_REL64:
928 /* 64 bits relative (used by features fixups) */
929 *location = value - (unsigned long)location;
930 break;
931
932 case R_PPC64_REL32:
933 /* 32 bits relative (used by relative exception tables) */
934 /* Convert value to relative */
935 value -= (unsigned long)location;
936 if (value + 0x80000000 > 0xffffffff) {
937 pr_err("%s: REL32 %li out of range!\n",
938 me->name, (long int)value);
939 return -ENOEXEC;
940 }
941 *(u32 *)location = value;
942 break;
943
944 #ifdef CONFIG_PPC_KERNEL_PCREL
945 case R_PPC64_PCREL34: {
946 unsigned long absvalue = value;
947
948 /* Convert value to relative */
949 value -= (unsigned long)location;
950
951 if (value + 0x200000000 > 0x3ffffffff) {
952 if (sym->st_shndx != me->arch.pcpu_section) {
953 pr_err("%s: REL34 %li out of range!\n",
954 me->name, (long)value);
955 return -ENOEXEC;
956 }
957
958 /*
959 * per-cpu section is special cased because
960 * it is moved during loading, so has to be
961 * converted to use GOT.
962 */
963 value = got_for_addr(sechdrs, absvalue, me,
964 strtab + sym->st_name);
965 if (!value)
966 return -ENOENT;
967 value -= (unsigned long)location;
968
969 /* Turn pla into pld */
970 if (patch_instruction((u32 *)location,
971 ppc_inst_prefix((*(u32 *)location & ~0x02000000),
972 (*((u32 *)location + 1) & ~0xf8000000) | 0xe4000000)))
973 return -EFAULT;
974 }
975
976 if (patch_instruction((u32 *)location,
977 ppc_inst_prefix((*(u32 *)location & ~0x3ffff) | IMM_H18(value),
978 (*((u32 *)location + 1) & ~0xffff) | IMM_L(value))))
979 return -EFAULT;
980
981 break;
982 }
983
984 #else
985 case R_PPC64_TOCSAVE:
986 /*
987 * Marker reloc indicates we don't have to save r2.
988 * That would only save us one instruction, so ignore
989 * it.
990 */
991 break;
992 #endif
993
994 case R_PPC64_ENTRY:
995 if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL))
996 break;
997
998 /*
999 * Optimize ELFv2 large code model entry point if
1000 * the TOC is within 2GB range of current location.
1001 */
1002 value = my_r2(sechdrs, me) - (unsigned long)location;
1003 if (value + 0x80008000 > 0xffffffff)
1004 break;
1005 /*
1006 * Check for the large code model prolog sequence:
1007 * ld r2, ...(r12)
1008 * add r2, r2, r12
1009 */
1010 if ((((uint32_t *)location)[0] & ~0xfffc) != PPC_RAW_LD(_R2, _R12, 0))
1011 break;
1012 if (((uint32_t *)location)[1] != PPC_RAW_ADD(_R2, _R2, _R12))
1013 break;
1014 /*
1015 * If found, replace it with:
1016 * addis r2, r12, (.TOC.-func)@ha
1017 * addi r2, r2, (.TOC.-func)@l
1018 */
1019 ((uint32_t *)location)[0] = PPC_RAW_ADDIS(_R2, _R12, PPC_HA(value));
1020 ((uint32_t *)location)[1] = PPC_RAW_ADDI(_R2, _R2, PPC_LO(value));
1021 break;
1022
1023 case R_PPC64_REL16_HA:
1024 /* Subtract location pointer */
1025 value -= (unsigned long)location;
1026 value = ((value + 0x8000) >> 16);
1027 *((uint16_t *) location)
1028 = (*((uint16_t *) location) & ~0xffff)
1029 | (value & 0xffff);
1030 break;
1031
1032 case R_PPC64_REL16_LO:
1033 /* Subtract location pointer */
1034 value -= (unsigned long)location;
1035 *((uint16_t *) location)
1036 = (*((uint16_t *) location) & ~0xffff)
1037 | (value & 0xffff);
1038 break;
1039
1040 #ifdef CONFIG_PPC_KERNEL_PCREL
1041 case R_PPC64_GOT_PCREL34:
1042 value = got_for_addr(sechdrs, value, me,
1043 strtab + sym->st_name);
1044 if (!value)
1045 return -ENOENT;
1046 value -= (unsigned long)location;
1047 ((uint32_t *)location)[0] = (((uint32_t *)location)[0] & ~0x3ffff) |
1048 ((value >> 16) & 0x3ffff);
1049 ((uint32_t *)location)[1] = (((uint32_t *)location)[1] & ~0xffff) |
1050 (value & 0xffff);
1051 break;
1052 #endif
1053
1054 default:
1055 pr_err("%s: Unknown ADD relocation: %lu\n",
1056 me->name,
1057 (unsigned long)ELF64_R_TYPE(rela[i].r_info));
1058 return -ENOEXEC;
1059 }
1060 }
1061
1062 return 0;
1063 }
1064
1065 #ifdef CONFIG_DYNAMIC_FTRACE
1066 int module_trampoline_target(struct module *mod, unsigned long addr,
1067 unsigned long *target)
1068 {
1069 struct ppc64_stub_entry *stub;
1070 func_desc_t funcdata;
1071 u32 magic;
1072
1073 if (!within_module_core(addr, mod)) {
1074 pr_err("%s: stub %lx not in module %s\n", __func__, addr, mod->name);
1075 return -EFAULT;
1076 }
1077
1078 stub = (struct ppc64_stub_entry *)addr;
1079
1080 if (copy_from_kernel_nofault(&magic, &stub->magic,
1081 sizeof(magic))) {
1082 pr_err("%s: fault reading magic for stub %lx for %s\n", __func__, addr, mod->name);
1083 return -EFAULT;
1084 }
1085
1086 if (magic != STUB_MAGIC) {
1087 pr_err("%s: bad magic for stub %lx for %s\n", __func__, addr, mod->name);
1088 return -EFAULT;
1089 }
1090
1091 if (copy_from_kernel_nofault(&funcdata, &stub->funcdata,
1092 sizeof(funcdata))) {
1093 pr_err("%s: fault reading funcdata for stub %lx for %s\n", __func__, addr, mod->name);
1094 return -EFAULT;
1095 }
1096
1097 *target = stub_func_addr(funcdata);
1098
1099 return 0;
1100 }
1101
1102 static int setup_ftrace_ool_stubs(const Elf64_Shdr *sechdrs, unsigned long addr, struct module *me)
1103 {
1104 #ifdef CONFIG_PPC_FTRACE_OUT_OF_LINE
1105 unsigned int i, total_stubs, num_stubs;
1106 struct ppc64_stub_entry *stub;
1107
1108 total_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stub);
1109 num_stubs = roundup(me->arch.ool_stub_count * sizeof(struct ftrace_ool_stub),
1110 sizeof(struct ppc64_stub_entry)) / sizeof(struct ppc64_stub_entry);
1111
1112 /* Find the next available entry */
1113 stub = (void *)sechdrs[me->arch.stubs_section].sh_addr;
1114 for (i = 0; stub_func_addr(stub[i].funcdata); i++)
1115 if (WARN_ON(i >= total_stubs))
1116 return -1;
1117
1118 if (WARN_ON(i + num_stubs > total_stubs))
1119 return -1;
1120
1121 stub += i;
1122 me->arch.ool_stubs = (struct ftrace_ool_stub *)stub;
1123
1124 /* reserve stubs */
1125 for (i = 0; i < num_stubs; i++)
1126 if (patch_u32((void *)&stub->funcdata, PPC_RAW_NOP()))
1127 return -1;
1128 #endif
1129
1130 return 0;
1131 }
1132
1133 int module_finalize_ftrace(struct module *mod, const Elf_Shdr *sechdrs)
1134 {
1135 mod->arch.tramp = stub_for_addr(sechdrs,
1136 (unsigned long)ftrace_caller,
1137 mod,
1138 "ftrace_caller");
1139 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1140 mod->arch.tramp_regs = stub_for_addr(sechdrs,
1141 (unsigned long)ftrace_regs_caller,
1142 mod,
1143 "ftrace_regs_caller");
1144 if (!mod->arch.tramp_regs)
1145 return -ENOENT;
1146 #endif
1147
1148 if (!mod->arch.tramp)
1149 return -ENOENT;
1150
1151 if (setup_ftrace_ool_stubs(sechdrs, mod->arch.tramp, mod))
1152 return -ENOENT;
1153
1154 return 0;
1155 }
1156 #endif
Kernel DRM miscellaneous fixes and cross-tree changes