1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * linux/arch/arm/kernel/module.c
4 *
5 * Copyright (C) 2002 Russell King.
6 * Modified for nommu by Hyok S. Choi
7 *
8 * Module allocation method suggested by Andi Kleen.
9 */
10 #include <linux/module.h>
11 #include <linux/moduleloader.h>
12 #include <linux/kernel.h>
13 #include <linux/mm.h>
14 #include <linux/elf.h>
15 #include <linux/vmalloc.h>
16 #include <linux/fs.h>
17 #include <linux/string.h>
18 #include <linux/gfp.h>
19
20 #include <asm/sections.h>
21 #include <asm/smp_plat.h>
22 #include <asm/unwind.h>
23 #include <asm/opcodes.h>
24
25 #ifdef CONFIG_XIP_KERNEL
26 /*
27 * The XIP kernel text is mapped in the module area for modules and
28 * some other stuff to work without any indirect relocations.
29 * MODULES_VADDR is redefined here and not in asm/memory.h to avoid
30 * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off.
31 */
32 #undef MODULES_VADDR
33 #define MODULES_VADDR (((unsigned long)_exiprom + ~PMD_MASK) & PMD_MASK)
34 #endif
35
36 #ifdef CONFIG_MMU
module_alloc(unsigned long size)37 void *module_alloc(unsigned long size)
38 {
39 gfp_t gfp_mask = GFP_KERNEL;
40 void *p;
41
42 /* Silence the initial allocation */
43 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS))
44 gfp_mask |= __GFP_NOWARN;
45
46 p = __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
47 gfp_mask, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
48 __builtin_return_address(0));
49 if (!IS_ENABLED(CONFIG_ARM_MODULE_PLTS) || p)
50 return p;
51 return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
52 GFP_KERNEL, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
53 __builtin_return_address(0));
54 }
55 #endif
56
module_init_section(const char * name)57 bool module_init_section(const char *name)
58 {
59 return strstarts(name, ".init") ||
60 strstarts(name, ".ARM.extab.init") ||
61 strstarts(name, ".ARM.exidx.init");
62 }
63
module_exit_section(const char * name)64 bool module_exit_section(const char *name)
65 {
66 return strstarts(name, ".exit") ||
67 strstarts(name, ".ARM.extab.exit") ||
68 strstarts(name, ".ARM.exidx.exit");
69 }
70
71 int
apply_relocate(Elf32_Shdr * sechdrs,const char * strtab,unsigned int symindex,unsigned int relindex,struct module * module)72 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
73 unsigned int relindex, struct module *module)
74 {
75 Elf32_Shdr *symsec = sechdrs + symindex;
76 Elf32_Shdr *relsec = sechdrs + relindex;
77 Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
78 Elf32_Rel *rel = (void *)relsec->sh_addr;
79 unsigned int i;
80
81 for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
82 unsigned long loc;
83 Elf32_Sym *sym;
84 const char *symname;
85 s32 offset;
86 u32 tmp;
87 #ifdef CONFIG_THUMB2_KERNEL
88 u32 upper, lower, sign, j1, j2;
89 #endif
90
91 offset = ELF32_R_SYM(rel->r_info);
92 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
93 pr_err("%s: section %u reloc %u: bad relocation sym offset\n",
94 module->name, relindex, i);
95 return -ENOEXEC;
96 }
97
98 sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
99 symname = strtab + sym->st_name;
100
101 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) {
102 pr_err("%s: section %u reloc %u sym '%s': out of bounds relocation, offset %d size %u\n",
103 module->name, relindex, i, symname,
104 rel->r_offset, dstsec->sh_size);
105 return -ENOEXEC;
106 }
107
108 loc = dstsec->sh_addr + rel->r_offset;
109
110 switch (ELF32_R_TYPE(rel->r_info)) {
111 case R_ARM_NONE:
112 /* ignore */
113 break;
114
115 case R_ARM_ABS32:
116 case R_ARM_TARGET1:
117 *(u32 *)loc += sym->st_value;
118 break;
119
120 case R_ARM_PC24:
121 case R_ARM_CALL:
122 case R_ARM_JUMP24:
123 if (sym->st_value & 3) {
124 pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (ARM -> Thumb)\n",
125 module->name, relindex, i, symname);
126 return -ENOEXEC;
127 }
128
129 offset = __mem_to_opcode_arm(*(u32 *)loc);
130 offset = (offset & 0x00ffffff) << 2;
131 if (offset & 0x02000000)
132 offset -= 0x04000000;
133
134 offset += sym->st_value - loc;
135
136 /*
137 * Route through a PLT entry if 'offset' exceeds the
138 * supported range. Note that 'offset + loc + 8'
139 * contains the absolute jump target, i.e.,
140 * @sym + addend, corrected for the +8 PC bias.
141 */
142 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) &&
143 (offset <= (s32)0xfe000000 ||
144 offset >= (s32)0x02000000))
145 offset = get_module_plt(module, loc,
146 offset + loc + 8)
147 - loc - 8;
148
149 if (offset <= (s32)0xfe000000 ||
150 offset >= (s32)0x02000000) {
151 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
152 module->name, relindex, i, symname,
153 ELF32_R_TYPE(rel->r_info), loc,
154 sym->st_value);
155 return -ENOEXEC;
156 }
157
158 offset >>= 2;
159 offset &= 0x00ffffff;
160
161 *(u32 *)loc &= __opcode_to_mem_arm(0xff000000);
162 *(u32 *)loc |= __opcode_to_mem_arm(offset);
163 break;
164
165 case R_ARM_V4BX:
166 /* Preserve Rm and the condition code. Alter
167 * other bits to re-code instruction as
168 * MOV PC,Rm.
169 */
170 *(u32 *)loc &= __opcode_to_mem_arm(0xf000000f);
171 *(u32 *)loc |= __opcode_to_mem_arm(0x01a0f000);
172 break;
173
174 case R_ARM_PREL31:
175 offset = (*(s32 *)loc << 1) >> 1; /* sign extend */
176 offset += sym->st_value - loc;
177 if (offset >= 0x40000000 || offset < -0x40000000) {
178 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
179 module->name, relindex, i, symname,
180 ELF32_R_TYPE(rel->r_info), loc,
181 sym->st_value);
182 return -ENOEXEC;
183 }
184 *(u32 *)loc &= 0x80000000;
185 *(u32 *)loc |= offset & 0x7fffffff;
186 break;
187
188 case R_ARM_REL32:
189 *(u32 *)loc += sym->st_value - loc;
190 break;
191
192 case R_ARM_MOVW_ABS_NC:
193 case R_ARM_MOVT_ABS:
194 case R_ARM_MOVW_PREL_NC:
195 case R_ARM_MOVT_PREL:
196 offset = tmp = __mem_to_opcode_arm(*(u32 *)loc);
197 offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff);
198 offset = (offset ^ 0x8000) - 0x8000;
199
200 offset += sym->st_value;
201 if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_PREL ||
202 ELF32_R_TYPE(rel->r_info) == R_ARM_MOVW_PREL_NC)
203 offset -= loc;
204 if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS ||
205 ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_PREL)
206 offset >>= 16;
207
208 tmp &= 0xfff0f000;
209 tmp |= ((offset & 0xf000) << 4) |
210 (offset & 0x0fff);
211
212 *(u32 *)loc = __opcode_to_mem_arm(tmp);
213 break;
214
215 #ifdef CONFIG_THUMB2_KERNEL
216 case R_ARM_THM_CALL:
217 case R_ARM_THM_JUMP24:
218 /*
219 * For function symbols, only Thumb addresses are
220 * allowed (no interworking).
221 *
222 * For non-function symbols, the destination
223 * has no specific ARM/Thumb disposition, so
224 * the branch is resolved under the assumption
225 * that interworking is not required.
226 */
227 if (ELF32_ST_TYPE(sym->st_info) == STT_FUNC &&
228 !(sym->st_value & 1)) {
229 pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (Thumb -> ARM)\n",
230 module->name, relindex, i, symname);
231 return -ENOEXEC;
232 }
233
234 upper = __mem_to_opcode_thumb16(*(u16 *)loc);
235 lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
236
237 /*
238 * 25 bit signed address range (Thumb-2 BL and B.W
239 * instructions):
240 * S:I1:I2:imm10:imm11:0
241 * where:
242 * S = upper[10] = offset[24]
243 * I1 = ~(J1 ^ S) = offset[23]
244 * I2 = ~(J2 ^ S) = offset[22]
245 * imm10 = upper[9:0] = offset[21:12]
246 * imm11 = lower[10:0] = offset[11:1]
247 * J1 = lower[13]
248 * J2 = lower[11]
249 */
250 sign = (upper >> 10) & 1;
251 j1 = (lower >> 13) & 1;
252 j2 = (lower >> 11) & 1;
253 offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) |
254 ((~(j2 ^ sign) & 1) << 22) |
255 ((upper & 0x03ff) << 12) |
256 ((lower & 0x07ff) << 1);
257 if (offset & 0x01000000)
258 offset -= 0x02000000;
259 offset += sym->st_value - loc;
260
261 /*
262 * Route through a PLT entry if 'offset' exceeds the
263 * supported range.
264 */
265 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) &&
266 (offset <= (s32)0xff000000 ||
267 offset >= (s32)0x01000000))
268 offset = get_module_plt(module, loc,
269 offset + loc + 4)
270 - loc - 4;
271
272 if (offset <= (s32)0xff000000 ||
273 offset >= (s32)0x01000000) {
274 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
275 module->name, relindex, i, symname,
276 ELF32_R_TYPE(rel->r_info), loc,
277 sym->st_value);
278 return -ENOEXEC;
279 }
280
281 sign = (offset >> 24) & 1;
282 j1 = sign ^ (~(offset >> 23) & 1);
283 j2 = sign ^ (~(offset >> 22) & 1);
284 upper = (u16)((upper & 0xf800) | (sign << 10) |
285 ((offset >> 12) & 0x03ff));
286 lower = (u16)((lower & 0xd000) |
287 (j1 << 13) | (j2 << 11) |
288 ((offset >> 1) & 0x07ff));
289
290 *(u16 *)loc = __opcode_to_mem_thumb16(upper);
291 *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower);
292 break;
293
294 case R_ARM_THM_MOVW_ABS_NC:
295 case R_ARM_THM_MOVT_ABS:
296 case R_ARM_THM_MOVW_PREL_NC:
297 case R_ARM_THM_MOVT_PREL:
298 upper = __mem_to_opcode_thumb16(*(u16 *)loc);
299 lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
300
301 /*
302 * MOVT/MOVW instructions encoding in Thumb-2:
303 *
304 * i = upper[10]
305 * imm4 = upper[3:0]
306 * imm3 = lower[14:12]
307 * imm8 = lower[7:0]
308 *
309 * imm16 = imm4:i:imm3:imm8
310 */
311 offset = ((upper & 0x000f) << 12) |
312 ((upper & 0x0400) << 1) |
313 ((lower & 0x7000) >> 4) | (lower & 0x00ff);
314 offset = (offset ^ 0x8000) - 0x8000;
315 offset += sym->st_value;
316
317 if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_PREL ||
318 ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVW_PREL_NC)
319 offset -= loc;
320 if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS ||
321 ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_PREL)
322 offset >>= 16;
323
324 upper = (u16)((upper & 0xfbf0) |
325 ((offset & 0xf000) >> 12) |
326 ((offset & 0x0800) >> 1));
327 lower = (u16)((lower & 0x8f00) |
328 ((offset & 0x0700) << 4) |
329 (offset & 0x00ff));
330 *(u16 *)loc = __opcode_to_mem_thumb16(upper);
331 *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower);
332 break;
333 #endif
334
335 default:
336 pr_err("%s: unknown relocation: %u\n",
337 module->name, ELF32_R_TYPE(rel->r_info));
338 return -ENOEXEC;
339 }
340 }
341 return 0;
342 }
343
344 struct mod_unwind_map {
345 const Elf_Shdr *unw_sec;
346 const Elf_Shdr *txt_sec;
347 };
348
find_mod_section(const Elf32_Ehdr * hdr,const Elf_Shdr * sechdrs,const char * name)349 static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr,
350 const Elf_Shdr *sechdrs, const char *name)
351 {
352 const Elf_Shdr *s, *se;
353 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
354
355 for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++)
356 if (strcmp(name, secstrs + s->sh_name) == 0)
357 return s;
358
359 return NULL;
360 }
361
362 extern void fixup_pv_table(const void *, unsigned long);
363 extern void fixup_smp(const void *, unsigned long);
364
module_finalize(const Elf32_Ehdr * hdr,const Elf_Shdr * sechdrs,struct module * mod)365 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
366 struct module *mod)
367 {
368 const Elf_Shdr *s = NULL;
369 #ifdef CONFIG_ARM_UNWIND
370 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
371 const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum;
372 struct mod_unwind_map maps[ARM_SEC_MAX];
373 int i;
374
375 memset(maps, 0, sizeof(maps));
376
377 for (s = sechdrs; s < sechdrs_end; s++) {
378 const char *secname = secstrs + s->sh_name;
379
380 if (!(s->sh_flags & SHF_ALLOC))
381 continue;
382
383 if (strcmp(".ARM.exidx.init.text", secname) == 0)
384 maps[ARM_SEC_INIT].unw_sec = s;
385 else if (strcmp(".ARM.exidx", secname) == 0)
386 maps[ARM_SEC_CORE].unw_sec = s;
387 else if (strcmp(".ARM.exidx.exit.text", secname) == 0)
388 maps[ARM_SEC_EXIT].unw_sec = s;
389 else if (strcmp(".ARM.exidx.text.unlikely", secname) == 0)
390 maps[ARM_SEC_UNLIKELY].unw_sec = s;
391 else if (strcmp(".ARM.exidx.text.hot", secname) == 0)
392 maps[ARM_SEC_HOT].unw_sec = s;
393 else if (strcmp(".init.text", secname) == 0)
394 maps[ARM_SEC_INIT].txt_sec = s;
395 else if (strcmp(".text", secname) == 0)
396 maps[ARM_SEC_CORE].txt_sec = s;
397 else if (strcmp(".exit.text", secname) == 0)
398 maps[ARM_SEC_EXIT].txt_sec = s;
399 else if (strcmp(".text.unlikely", secname) == 0)
400 maps[ARM_SEC_UNLIKELY].txt_sec = s;
401 else if (strcmp(".text.hot", secname) == 0)
402 maps[ARM_SEC_HOT].txt_sec = s;
403 }
404
405 for (i = 0; i < ARM_SEC_MAX; i++)
406 if (maps[i].unw_sec && maps[i].txt_sec)
407 mod->arch.unwind[i] =
408 unwind_table_add(maps[i].unw_sec->sh_addr,
409 maps[i].unw_sec->sh_size,
410 maps[i].txt_sec->sh_addr,
411 maps[i].txt_sec->sh_size);
412 #endif
413 #ifdef CONFIG_ARM_PATCH_PHYS_VIRT
414 s = find_mod_section(hdr, sechdrs, ".pv_table");
415 if (s)
416 fixup_pv_table((void *)s->sh_addr, s->sh_size);
417 #endif
418 s = find_mod_section(hdr, sechdrs, ".alt.smp.init");
419 if (s && !is_smp())
420 #ifdef CONFIG_SMP_ON_UP
421 fixup_smp((void *)s->sh_addr, s->sh_size);
422 #else
423 return -EINVAL;
424 #endif
425 return 0;
426 }
427
428 void
module_arch_cleanup(struct module * mod)429 module_arch_cleanup(struct module *mod)
430 {
431 #ifdef CONFIG_ARM_UNWIND
432 int i;
433
434 for (i = 0; i < ARM_SEC_MAX; i++) {
435 unwind_table_del(mod->arch.unwind[i]);
436 mod->arch.unwind[i] = NULL;
437 }
438 #endif
439 }
440
module_arch_freeing_init(struct module * mod)441 void __weak module_arch_freeing_init(struct module *mod)
442 {
443 #ifdef CONFIG_ARM_UNWIND
444 unwind_table_del(mod->arch.unwind[ARM_SEC_INIT]);
445 mod->arch.unwind[ARM_SEC_INIT] = NULL;
446 #endif
447 }
448