1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/arch/arm/kernel/module.c
5 * Copyright (C) 2002 Russell King.
6 * Modified for nommu by Hyok S. Choi
8 * Module allocation method suggested by Andi Kleen.
10 #include <linux/module.h>
11 #include <linux/moduleloader.h>
12 #include <linux/kernel.h>
14 #include <linux/elf.h>
15 #include <linux/vmalloc.h>
17 #include <linux/string.h>
18 #include <linux/gfp.h>
20 #include <asm/sections.h>
21 #include <asm/smp_plat.h>
22 #include <asm/unwind.h>
23 #include <asm/opcodes.h>
25 #ifdef CONFIG_XIP_KERNEL
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.
33 #define MODULES_VADDR (((unsigned long)_exiprom + ~PMD_MASK) & PMD_MASK)
37 void *module_alloc(unsigned long size)
39 gfp_t gfp_mask = GFP_KERNEL;
42 /* Silence the initial allocation */
43 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS))
44 gfp_mask |= __GFP_NOWARN;
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)
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));
57 bool module_init_section(const char *name)
59 return strstarts(name, ".init") ||
60 strstarts(name, ".ARM.extab.init") ||
61 strstarts(name, ".ARM.exidx.init");
64 bool module_exit_section(const char *name)
66 return strstarts(name, ".exit") ||
67 strstarts(name, ".ARM.extab.exit") ||
68 strstarts(name, ".ARM.exidx.exit");
71 #ifdef CONFIG_ARM_HAS_GROUP_RELOCS
73 * This implements the partitioning algorithm for group relocations as
74 * documented in the ARM AArch32 ELF psABI (IHI 0044).
76 * A single PC-relative symbol reference is divided in up to 3 add or subtract
77 * operations, where the final one could be incorporated into a load/store
78 * instruction with immediate offset. E.g.,
80 * ADD Rd, PC, #... or ADD Rd, PC, #...
81 * ADD Rd, Rd, #... ADD Rd, Rd, #...
82 * LDR Rd, [Rd, #...] ADD Rd, Rd, #...
84 * The latter has a guaranteed range of only 16 MiB (3x8 == 24 bits), so it is
85 * of limited use in the kernel. However, the ADD/ADD/LDR combo has a range of
86 * -/+ 256 MiB, (2x8 + 12 == 28 bits), which means it has sufficient range for
87 * any in-kernel symbol reference (unless module PLTs are being used).
89 * The main advantage of this approach over the typical pattern using a literal
90 * load is that literal loads may miss in the D-cache, and generally lead to
91 * lower cache efficiency for variables that are referenced often from many
92 * different places in the code.
94 static u32 get_group_rem(u32 group, u32 *offset)
99 shift = val ? (31 - __fls(val)) & ~1 : 32;
103 val &= 0xffffff >> shift;
110 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
111 unsigned int relindex, struct module *module)
113 Elf32_Shdr *symsec = sechdrs + symindex;
114 Elf32_Shdr *relsec = sechdrs + relindex;
115 Elf32_Shdr *dstsec = sechdrs + relsec->sh_info;
116 Elf32_Rel *rel = (void *)relsec->sh_addr;
119 for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
123 #ifdef CONFIG_ARM_HAS_GROUP_RELOCS
124 u32 shift, group = 1;
128 #ifdef CONFIG_THUMB2_KERNEL
129 u32 upper, lower, sign, j1, j2;
132 offset = ELF32_R_SYM(rel->r_info);
133 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
134 pr_err("%s: section %u reloc %u: bad relocation sym offset\n",
135 module->name, relindex, i);
139 sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
140 symname = strtab + sym->st_name;
142 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) {
143 pr_err("%s: section %u reloc %u sym '%s': out of bounds relocation, offset %d size %u\n",
144 module->name, relindex, i, symname,
145 rel->r_offset, dstsec->sh_size);
149 loc = dstsec->sh_addr + rel->r_offset;
151 switch (ELF32_R_TYPE(rel->r_info)) {
158 *(u32 *)loc += sym->st_value;
164 if (sym->st_value & 3) {
165 pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (ARM -> Thumb)\n",
166 module->name, relindex, i, symname);
170 offset = __mem_to_opcode_arm(*(u32 *)loc);
171 offset = (offset & 0x00ffffff) << 2;
172 if (offset & 0x02000000)
173 offset -= 0x04000000;
175 offset += sym->st_value - loc;
178 * Route through a PLT entry if 'offset' exceeds the
179 * supported range. Note that 'offset + loc + 8'
180 * contains the absolute jump target, i.e.,
181 * @sym + addend, corrected for the +8 PC bias.
183 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) &&
184 (offset <= (s32)0xfe000000 ||
185 offset >= (s32)0x02000000))
186 offset = get_module_plt(module, loc,
190 if (offset <= (s32)0xfe000000 ||
191 offset >= (s32)0x02000000) {
192 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
193 module->name, relindex, i, symname,
194 ELF32_R_TYPE(rel->r_info), loc,
200 offset &= 0x00ffffff;
202 *(u32 *)loc &= __opcode_to_mem_arm(0xff000000);
203 *(u32 *)loc |= __opcode_to_mem_arm(offset);
207 /* Preserve Rm and the condition code. Alter
208 * other bits to re-code instruction as
211 *(u32 *)loc &= __opcode_to_mem_arm(0xf000000f);
212 *(u32 *)loc |= __opcode_to_mem_arm(0x01a0f000);
216 offset = (*(s32 *)loc << 1) >> 1; /* sign extend */
217 offset += sym->st_value - loc;
218 if (offset >= 0x40000000 || offset < -0x40000000) {
219 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
220 module->name, relindex, i, symname,
221 ELF32_R_TYPE(rel->r_info), loc,
225 *(u32 *)loc &= 0x80000000;
226 *(u32 *)loc |= offset & 0x7fffffff;
230 *(u32 *)loc += sym->st_value - loc;
233 case R_ARM_MOVW_ABS_NC:
235 case R_ARM_MOVW_PREL_NC:
236 case R_ARM_MOVT_PREL:
237 offset = tmp = __mem_to_opcode_arm(*(u32 *)loc);
238 offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff);
239 offset = (offset ^ 0x8000) - 0x8000;
241 offset += sym->st_value;
242 if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_PREL ||
243 ELF32_R_TYPE(rel->r_info) == R_ARM_MOVW_PREL_NC)
245 if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS ||
246 ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_PREL)
250 tmp |= ((offset & 0xf000) << 4) |
253 *(u32 *)loc = __opcode_to_mem_arm(tmp);
256 #ifdef CONFIG_ARM_HAS_GROUP_RELOCS
257 case R_ARM_ALU_PC_G0_NC:
260 case R_ARM_ALU_PC_G1_NC:
261 tmp = __mem_to_opcode_arm(*(u32 *)loc);
262 offset = ror32(tmp & 0xff, (tmp & 0xf00) >> 7);
265 offset += sym->st_value - loc;
268 tmp = (tmp & ~BIT(23)) | BIT(22); // SUB opcode
270 tmp = (tmp & ~BIT(22)) | BIT(23); // ADD opcode
273 shift = get_group_rem(group, &offset);
275 offset >>= 24 - shift;
276 offset |= (shift + 8) << 7;
278 *(u32 *)loc = __opcode_to_mem_arm((tmp & ~0xfff) | offset);
281 case R_ARM_LDR_PC_G2:
282 tmp = __mem_to_opcode_arm(*(u32 *)loc);
283 offset = tmp & 0xfff;
284 if (~tmp & BIT(23)) // U bit cleared?
286 offset += sym->st_value - loc;
289 tmp &= ~BIT(23); // clear U bit
291 tmp |= BIT(23); // set U bit
293 get_group_rem(2, &offset);
295 if (offset > 0xfff) {
296 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
297 module->name, relindex, i, symname,
298 ELF32_R_TYPE(rel->r_info), loc,
302 *(u32 *)loc = __opcode_to_mem_arm((tmp & ~0xfff) | offset);
305 #ifdef CONFIG_THUMB2_KERNEL
307 case R_ARM_THM_JUMP24:
309 * For function symbols, only Thumb addresses are
310 * allowed (no interworking).
312 * For non-function symbols, the destination
313 * has no specific ARM/Thumb disposition, so
314 * the branch is resolved under the assumption
315 * that interworking is not required.
317 if (ELF32_ST_TYPE(sym->st_info) == STT_FUNC &&
318 !(sym->st_value & 1)) {
319 pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (Thumb -> ARM)\n",
320 module->name, relindex, i, symname);
324 upper = __mem_to_opcode_thumb16(*(u16 *)loc);
325 lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
328 * 25 bit signed address range (Thumb-2 BL and B.W
330 * S:I1:I2:imm10:imm11:0
332 * S = upper[10] = offset[24]
333 * I1 = ~(J1 ^ S) = offset[23]
334 * I2 = ~(J2 ^ S) = offset[22]
335 * imm10 = upper[9:0] = offset[21:12]
336 * imm11 = lower[10:0] = offset[11:1]
340 sign = (upper >> 10) & 1;
341 j1 = (lower >> 13) & 1;
342 j2 = (lower >> 11) & 1;
343 offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) |
344 ((~(j2 ^ sign) & 1) << 22) |
345 ((upper & 0x03ff) << 12) |
346 ((lower & 0x07ff) << 1);
347 if (offset & 0x01000000)
348 offset -= 0x02000000;
349 offset += sym->st_value - loc;
352 * Route through a PLT entry if 'offset' exceeds the
355 if (IS_ENABLED(CONFIG_ARM_MODULE_PLTS) &&
356 (offset <= (s32)0xff000000 ||
357 offset >= (s32)0x01000000))
358 offset = get_module_plt(module, loc,
362 if (offset <= (s32)0xff000000 ||
363 offset >= (s32)0x01000000) {
364 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
365 module->name, relindex, i, symname,
366 ELF32_R_TYPE(rel->r_info), loc,
371 sign = (offset >> 24) & 1;
372 j1 = sign ^ (~(offset >> 23) & 1);
373 j2 = sign ^ (~(offset >> 22) & 1);
374 upper = (u16)((upper & 0xf800) | (sign << 10) |
375 ((offset >> 12) & 0x03ff));
376 lower = (u16)((lower & 0xd000) |
377 (j1 << 13) | (j2 << 11) |
378 ((offset >> 1) & 0x07ff));
380 *(u16 *)loc = __opcode_to_mem_thumb16(upper);
381 *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower);
384 case R_ARM_THM_MOVW_ABS_NC:
385 case R_ARM_THM_MOVT_ABS:
386 case R_ARM_THM_MOVW_PREL_NC:
387 case R_ARM_THM_MOVT_PREL:
388 upper = __mem_to_opcode_thumb16(*(u16 *)loc);
389 lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
392 * MOVT/MOVW instructions encoding in Thumb-2:
396 * imm3 = lower[14:12]
399 * imm16 = imm4:i:imm3:imm8
401 offset = ((upper & 0x000f) << 12) |
402 ((upper & 0x0400) << 1) |
403 ((lower & 0x7000) >> 4) | (lower & 0x00ff);
404 offset = (offset ^ 0x8000) - 0x8000;
405 offset += sym->st_value;
407 if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_PREL ||
408 ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVW_PREL_NC)
410 if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS ||
411 ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_PREL)
414 upper = (u16)((upper & 0xfbf0) |
415 ((offset & 0xf000) >> 12) |
416 ((offset & 0x0800) >> 1));
417 lower = (u16)((lower & 0x8f00) |
418 ((offset & 0x0700) << 4) |
420 *(u16 *)loc = __opcode_to_mem_thumb16(upper);
421 *(u16 *)(loc + 2) = __opcode_to_mem_thumb16(lower);
426 pr_err("%s: unknown relocation: %u\n",
427 module->name, ELF32_R_TYPE(rel->r_info));
434 struct mod_unwind_map {
435 const Elf_Shdr *unw_sec;
436 const Elf_Shdr *txt_sec;
439 static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr,
440 const Elf_Shdr *sechdrs, const char *name)
442 const Elf_Shdr *s, *se;
443 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
445 for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++)
446 if (strcmp(name, secstrs + s->sh_name) == 0)
452 extern void fixup_pv_table(const void *, unsigned long);
453 extern void fixup_smp(const void *, unsigned long);
455 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs,
458 const Elf_Shdr *s = NULL;
459 #ifdef CONFIG_ARM_UNWIND
460 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
461 const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum;
462 struct mod_unwind_map maps[ARM_SEC_MAX];
465 memset(maps, 0, sizeof(maps));
467 for (s = sechdrs; s < sechdrs_end; s++) {
468 const char *secname = secstrs + s->sh_name;
470 if (!(s->sh_flags & SHF_ALLOC))
473 if (strcmp(".ARM.exidx.init.text", secname) == 0)
474 maps[ARM_SEC_INIT].unw_sec = s;
475 else if (strcmp(".ARM.exidx", secname) == 0)
476 maps[ARM_SEC_CORE].unw_sec = s;
477 else if (strcmp(".ARM.exidx.exit.text", secname) == 0)
478 maps[ARM_SEC_EXIT].unw_sec = s;
479 else if (strcmp(".ARM.exidx.text.unlikely", secname) == 0)
480 maps[ARM_SEC_UNLIKELY].unw_sec = s;
481 else if (strcmp(".ARM.exidx.text.hot", secname) == 0)
482 maps[ARM_SEC_HOT].unw_sec = s;
483 else if (strcmp(".init.text", secname) == 0)
484 maps[ARM_SEC_INIT].txt_sec = s;
485 else if (strcmp(".text", secname) == 0)
486 maps[ARM_SEC_CORE].txt_sec = s;
487 else if (strcmp(".exit.text", secname) == 0)
488 maps[ARM_SEC_EXIT].txt_sec = s;
489 else if (strcmp(".text.unlikely", secname) == 0)
490 maps[ARM_SEC_UNLIKELY].txt_sec = s;
491 else if (strcmp(".text.hot", secname) == 0)
492 maps[ARM_SEC_HOT].txt_sec = s;
495 for (i = 0; i < ARM_SEC_MAX; i++)
496 if (maps[i].unw_sec && maps[i].txt_sec)
497 mod->arch.unwind[i] =
498 unwind_table_add(maps[i].unw_sec->sh_addr,
499 maps[i].unw_sec->sh_size,
500 maps[i].txt_sec->sh_addr,
501 maps[i].txt_sec->sh_size);
503 #ifdef CONFIG_ARM_PATCH_PHYS_VIRT
504 s = find_mod_section(hdr, sechdrs, ".pv_table");
506 fixup_pv_table((void *)s->sh_addr, s->sh_size);
508 s = find_mod_section(hdr, sechdrs, ".alt.smp.init");
510 #ifdef CONFIG_SMP_ON_UP
511 fixup_smp((void *)s->sh_addr, s->sh_size);
519 module_arch_cleanup(struct module *mod)
521 #ifdef CONFIG_ARM_UNWIND
524 for (i = 0; i < ARM_SEC_MAX; i++) {
525 unwind_table_del(mod->arch.unwind[i]);
526 mod->arch.unwind[i] = NULL;
531 void __weak module_arch_freeing_init(struct module *mod)
533 #ifdef CONFIG_ARM_UNWIND
534 unwind_table_del(mod->arch.unwind[ARM_SEC_INIT]);
535 mod->arch.unwind[ARM_SEC_INIT] = NULL;