1 // SPDX-License-Identifier: GPL-2.0-only !! 1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* 2 /*
3 * Kernel module loader for Hexagon <<
4 * 3 *
5 * Copyright (c) 2010-2011, The Linux Foundati !! 4 * Copyright (C) 2001 Rusty Russell.
>> 5 * Copyright (C) 2003, 2004 Ralf Baechle (ralf@linux-mips.org)
>> 6 * Copyright (C) 2005 Thiemo Seufer
6 */ 7 */
7 8
8 #include <asm/module.h> !! 9 #undef DEBUG
9 #include <linux/elf.h> !! 10
10 #include <linux/module.h> !! 11 #include <linux/extable.h>
11 #include <linux/moduleloader.h> 12 #include <linux/moduleloader.h>
12 #include <linux/vmalloc.h> !! 13 #include <linux/elf.h>
>> 14 #include <linux/mm.h>
>> 15 #include <linux/numa.h>
>> 16 #include <linux/slab.h>
>> 17 #include <linux/fs.h>
>> 18 #include <linux/string.h>
>> 19 #include <linux/kernel.h>
>> 20 #include <linux/spinlock.h>
>> 21 #include <linux/jump_label.h>
>> 22 #include <asm/jump_label.h>
>> 23
>> 24 struct mips_hi16 {
>> 25 struct mips_hi16 *next;
>> 26 Elf_Addr *addr;
>> 27 Elf_Addr value;
>> 28 };
13 29
14 #if 0 !! 30 static LIST_HEAD(dbe_list);
15 #define DEBUGP printk !! 31 static DEFINE_SPINLOCK(dbe_lock);
16 #else <<
17 #define DEBUGP(fmt , ...) <<
18 #endif <<
19 32
20 /* !! 33 static void apply_r_mips_32(u32 *location, u32 base, Elf_Addr v)
21 * module_frob_arch_sections - tweak got/plt s !! 34 {
22 * @hdr - pointer to elf header !! 35 *location = base + v;
23 * @sechdrs - pointer to elf load section head !! 36 }
24 * @secstrings - symbol names !! 37
25 * @mod - pointer to module !! 38 static int apply_r_mips_26(struct module *me, u32 *location, u32 base,
26 */ !! 39 Elf_Addr v)
27 int module_frob_arch_sections(Elf_Ehdr *hdr, E !! 40 {
28 char *secstrin !! 41 if (v % 4) {
29 struct module !! 42 pr_err("module %s: dangerous R_MIPS_26 relocation\n",
30 { !! 43 me->name);
31 unsigned int i; !! 44 return -ENOEXEC;
32 int found = 0; !! 45 }
33 !! 46
34 /* Look for .plt and/or .got.plt and/o !! 47 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
35 for (i = 0; i < hdr->e_shnum; i++) { !! 48 pr_err("module %s: relocation overflow\n",
36 DEBUGP("Section %d is %s\n", i !! 49 me->name);
37 secstrings + sechdrs[i] !! 50 return -ENOEXEC;
38 if (strcmp(secstrings + sechdr <<
39 found = i+1; <<
40 if (strcmp(secstrings + sechdr <<
41 found = i+1; <<
42 if (strcmp(secstrings + sechdr <<
43 found = i+1; <<
44 } <<
45 <<
46 /* At this time, we don't support modu <<
47 if (found) { <<
48 printk(KERN_WARNING <<
49 "Module '%s' contains <<
50 mod->name); <<
51 /* return -ENOEXEC; */ <<
52 } 51 }
53 52
>> 53 *location = (*location & ~0x03ffffff) |
>> 54 ((base + (v >> 2)) & 0x03ffffff);
>> 55
54 return 0; 56 return 0;
55 } 57 }
56 58
57 /* !! 59 static int apply_r_mips_hi16(struct module *me, u32 *location, Elf_Addr v,
58 * apply_relocate_add - perform rela relocatio !! 60 bool rela)
59 * @sechdrs - pointer to section headers !! 61 {
60 * @strtab - some sort of start address? !! 62 struct mips_hi16 *n;
61 * @symindex - symbol index offset or somethin !! 63
62 * @relsec - address to relocate to? !! 64 if (rela) {
63 * @module - pointer to module !! 65 *location = (*location & 0xffff0000) |
>> 66 ((((long long) v + 0x8000LL) >> 16) & 0xffff);
>> 67 return 0;
>> 68 }
>> 69
>> 70 /*
>> 71 * We cannot relocate this one now because we don't know the value of
>> 72 * the carry we need to add. Save the information, and let LO16 do the
>> 73 * actual relocation.
>> 74 */
>> 75 n = kmalloc(sizeof *n, GFP_KERNEL);
>> 76 if (!n)
>> 77 return -ENOMEM;
>> 78
>> 79 n->addr = (Elf_Addr *)location;
>> 80 n->value = v;
>> 81 n->next = me->arch.r_mips_hi16_list;
>> 82 me->arch.r_mips_hi16_list = n;
>> 83
>> 84 return 0;
>> 85 }
>> 86
>> 87 static void free_relocation_chain(struct mips_hi16 *l)
>> 88 {
>> 89 struct mips_hi16 *next;
>> 90
>> 91 while (l) {
>> 92 next = l->next;
>> 93 kfree(l);
>> 94 l = next;
>> 95 }
>> 96 }
>> 97
>> 98 static int apply_r_mips_lo16(struct module *me, u32 *location,
>> 99 u32 base, Elf_Addr v, bool rela)
>> 100 {
>> 101 unsigned long insnlo = base;
>> 102 struct mips_hi16 *l;
>> 103 Elf_Addr val, vallo;
>> 104
>> 105 if (rela) {
>> 106 *location = (*location & 0xffff0000) | (v & 0xffff);
>> 107 return 0;
>> 108 }
>> 109
>> 110 /* Sign extend the addend we extract from the lo insn. */
>> 111 vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;
>> 112
>> 113 if (me->arch.r_mips_hi16_list != NULL) {
>> 114 l = me->arch.r_mips_hi16_list;
>> 115 while (l != NULL) {
>> 116 struct mips_hi16 *next;
>> 117 unsigned long insn;
>> 118
>> 119 /*
>> 120 * The value for the HI16 had best be the same.
>> 121 */
>> 122 if (v != l->value)
>> 123 goto out_danger;
>> 124
>> 125 /*
>> 126 * Do the HI16 relocation. Note that we actually don't
>> 127 * need to know anything about the LO16 itself, except
>> 128 * where to find the low 16 bits of the addend needed
>> 129 * by the LO16.
>> 130 */
>> 131 insn = *l->addr;
>> 132 val = ((insn & 0xffff) << 16) + vallo;
>> 133 val += v;
>> 134
>> 135 /*
>> 136 * Account for the sign extension that will happen in
>> 137 * the low bits.
>> 138 */
>> 139 val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff;
>> 140
>> 141 insn = (insn & ~0xffff) | val;
>> 142 *l->addr = insn;
>> 143
>> 144 next = l->next;
>> 145 kfree(l);
>> 146 l = next;
>> 147 }
>> 148
>> 149 me->arch.r_mips_hi16_list = NULL;
>> 150 }
>> 151
>> 152 /*
>> 153 * Ok, we're done with the HI16 relocs. Now deal with the LO16.
>> 154 */
>> 155 val = v + vallo;
>> 156 insnlo = (insnlo & ~0xffff) | (val & 0xffff);
>> 157 *location = insnlo;
>> 158
>> 159 return 0;
>> 160
>> 161 out_danger:
>> 162 free_relocation_chain(l);
>> 163 me->arch.r_mips_hi16_list = NULL;
>> 164
>> 165 pr_err("module %s: dangerous R_MIPS_LO16 relocation\n", me->name);
>> 166
>> 167 return -ENOEXEC;
>> 168 }
>> 169
>> 170 static int apply_r_mips_pc(struct module *me, u32 *location, u32 base,
>> 171 Elf_Addr v, unsigned int bits)
>> 172 {
>> 173 unsigned long mask = GENMASK(bits - 1, 0);
>> 174 unsigned long se_bits;
>> 175 long offset;
>> 176
>> 177 if (v % 4) {
>> 178 pr_err("module %s: dangerous R_MIPS_PC%u relocation\n",
>> 179 me->name, bits);
>> 180 return -ENOEXEC;
>> 181 }
>> 182
>> 183 /* retrieve & sign extend implicit addend if any */
>> 184 offset = base & mask;
>> 185 offset |= (offset & BIT(bits - 1)) ? ~mask : 0;
>> 186
>> 187 offset += ((long)v - (long)location) >> 2;
>> 188
>> 189 /* check the sign bit onwards are identical - ie. we didn't overflow */
>> 190 se_bits = (offset & BIT(bits - 1)) ? ~0ul : 0;
>> 191 if ((offset & ~mask) != (se_bits & ~mask)) {
>> 192 pr_err("module %s: relocation overflow\n", me->name);
>> 193 return -ENOEXEC;
>> 194 }
>> 195
>> 196 *location = (*location & ~mask) | (offset & mask);
>> 197
>> 198 return 0;
>> 199 }
>> 200
>> 201 static int apply_r_mips_pc16(struct module *me, u32 *location, u32 base,
>> 202 Elf_Addr v)
>> 203 {
>> 204 return apply_r_mips_pc(me, location, base, v, 16);
>> 205 }
>> 206
>> 207 static int apply_r_mips_pc21(struct module *me, u32 *location, u32 base,
>> 208 Elf_Addr v)
>> 209 {
>> 210 return apply_r_mips_pc(me, location, base, v, 21);
>> 211 }
>> 212
>> 213 static int apply_r_mips_pc26(struct module *me, u32 *location, u32 base,
>> 214 Elf_Addr v)
>> 215 {
>> 216 return apply_r_mips_pc(me, location, base, v, 26);
>> 217 }
>> 218
>> 219 static int apply_r_mips_64(u32 *location, Elf_Addr v, bool rela)
>> 220 {
>> 221 if (WARN_ON(!rela))
>> 222 return -EINVAL;
>> 223
>> 224 *(Elf_Addr *)location = v;
>> 225
>> 226 return 0;
>> 227 }
>> 228
>> 229 static int apply_r_mips_higher(u32 *location, Elf_Addr v, bool rela)
>> 230 {
>> 231 if (WARN_ON(!rela))
>> 232 return -EINVAL;
>> 233
>> 234 *location = (*location & 0xffff0000) |
>> 235 ((((long long)v + 0x80008000LL) >> 32) & 0xffff);
>> 236
>> 237 return 0;
>> 238 }
>> 239
>> 240 static int apply_r_mips_highest(u32 *location, Elf_Addr v, bool rela)
>> 241 {
>> 242 if (WARN_ON(!rela))
>> 243 return -EINVAL;
>> 244
>> 245 *location = (*location & 0xffff0000) |
>> 246 ((((long long)v + 0x800080008000LL) >> 48) & 0xffff);
>> 247
>> 248 return 0;
>> 249 }
>> 250
>> 251 /**
>> 252 * reloc_handler() - Apply a particular relocation to a module
>> 253 * @type: type of the relocation to apply
>> 254 * @me: the module to apply the reloc to
>> 255 * @location: the address at which the reloc is to be applied
>> 256 * @base: the existing value at location for REL-style; 0 for RELA-style
>> 257 * @v: the value of the reloc, with addend for RELA-style
>> 258 * @rela: indication of is this a RELA (true) or REL (false) relocation
>> 259 *
>> 260 * Each implemented relocation function applies a particular type of
>> 261 * relocation to the module @me. Relocs that may be found in either REL or RELA
>> 262 * variants can be handled by making use of the @base & @v parameters which are
>> 263 * set to values which abstract the difference away from the particular reloc
>> 264 * implementations.
64 * 265 *
65 * Perform rela relocations. !! 266 * Return: 0 upon success, else -ERRNO
66 */ 267 */
67 int apply_relocate_add(Elf_Shdr *sechdrs, cons !! 268 static int reloc_handler(u32 type, struct module *me, u32 *location, u32 base,
68 unsigned int symindex, !! 269 Elf_Addr v, bool rela)
69 struct module *module) <<
70 { 270 {
71 unsigned int i; !! 271 switch (type) {
72 Elf32_Sym *sym; !! 272 case R_MIPS_NONE:
73 uint32_t *location; !! 273 break;
74 uint32_t value; !! 274 case R_MIPS_32:
75 unsigned int nrelocs = sechdrs[relsec] !! 275 apply_r_mips_32(location, base, v);
76 Elf32_Rela *rela = (void *)sechdrs[rel !! 276 break;
77 Elf32_Word sym_info = sechdrs[relsec]. !! 277 case R_MIPS_26:
78 Elf32_Sym *sym_base = (Elf32_Sym *) se !! 278 return apply_r_mips_26(me, location, base, v);
79 void *loc_base = (void *) sechdrs[sym_ !! 279 case R_MIPS_HI16:
80 !! 280 return apply_r_mips_hi16(me, location, v, rela);
81 DEBUGP("Applying relocations in sectio !! 281 case R_MIPS_LO16:
82 relsec, sym_info, loc_base); !! 282 return apply_r_mips_lo16(me, location, base, v, rela);
83 !! 283 case R_MIPS_PC16:
84 for (i = 0; i < nrelocs; i++) { !! 284 return apply_r_mips_pc16(me, location, base, v);
85 !! 285 case R_MIPS_PC21_S2:
86 /* Symbol to relocate */ !! 286 return apply_r_mips_pc21(me, location, base, v);
87 sym = sym_base + ELF32_R_SYM(r !! 287 case R_MIPS_PC26_S2:
88 !! 288 return apply_r_mips_pc26(me, location, base, v);
89 /* Where to make the change */ !! 289 case R_MIPS_64:
90 location = loc_base + rela[i]. !! 290 return apply_r_mips_64(location, v, rela);
91 !! 291 case R_MIPS_HIGHER:
92 /* `Everything is relative'. * !! 292 return apply_r_mips_higher(location, v, rela);
93 value = sym->st_value + rela[i !! 293 case R_MIPS_HIGHEST:
94 !! 294 return apply_r_mips_highest(location, v, rela);
95 DEBUGP("%d: value=%08x loc=%p !! 295 default:
96 i, value, location, ELF !! 296 pr_err("%s: Unknown relocation type %u\n", me->name, type);
97 sym->st_name ? !! 297 return -EINVAL;
98 &strtab[sym->st_name] : !! 298 }
99 !! 299
100 switch (ELF32_R_TYPE(rela[i].r !! 300 return 0;
101 case R_HEXAGON_B22_PCREL: { !! 301 }
102 int dist = (int)(value !! 302
103 if ((dist < -0x0080000 !! 303 static int __apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
104 (dist >= 0x0080000 !! 304 unsigned int symindex, unsigned int relsec,
105 printk(KERN_ER !! 305 struct module *me, bool rela)
106 "%s: %s !! 306 {
107 module- !! 307 union {
108 "R_HEXA !! 308 Elf_Mips_Rel *rel;
109 dist, v !! 309 Elf_Mips_Rela *rela;
110 sym->st !! 310 } r;
111 &strtab !! 311 Elf_Sym *sym;
112 return -ENOEXE !! 312 u32 *location, base;
113 } !! 313 unsigned int i, type;
114 DEBUGP("B22_PCREL cont !! 314 Elf_Addr v;
115 *location &= ~0x01ff3f !! 315 int err = 0;
116 *location |= 0x00003ff !! 316 size_t reloc_sz;
117 *location |= 0x01ff000 !! 317
118 DEBUGP("Contents after !! 318 pr_debug("Applying relocate section %u to %u\n", relsec,
119 break; !! 319 sechdrs[relsec].sh_info);
>> 320
>> 321 r.rel = (void *)sechdrs[relsec].sh_addr;
>> 322 reloc_sz = rela ? sizeof(*r.rela) : sizeof(*r.rel);
>> 323 me->arch.r_mips_hi16_list = NULL;
>> 324 for (i = 0; i < sechdrs[relsec].sh_size / reloc_sz; i++) {
>> 325 /* This is where to make the change */
>> 326 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
>> 327 + r.rel->r_offset;
>> 328 /* This is the symbol it is referring to */
>> 329 sym = (Elf_Sym *)sechdrs[symindex].sh_addr
>> 330 + ELF_MIPS_R_SYM(*r.rel);
>> 331 if (sym->st_value >= -MAX_ERRNO) {
>> 332 /* Ignore unresolved weak symbol */
>> 333 if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
>> 334 continue;
>> 335 pr_warn("%s: Unknown symbol %s\n",
>> 336 me->name, strtab + sym->st_name);
>> 337 err = -ENOENT;
>> 338 goto out;
120 } 339 }
121 case R_HEXAGON_HI16: !! 340
122 value = (value>>16) & !! 341 type = ELF_MIPS_R_TYPE(*r.rel);
123 fallthrough; !! 342
124 case R_HEXAGON_LO16: !! 343 if (rela) {
125 *location &= ~0x00c03f !! 344 v = sym->st_value + r.rela->r_addend;
126 *location |= value & 0 !! 345 base = 0;
127 *location |= (value & !! 346 r.rela = &r.rela[1];
128 break; !! 347 } else {
129 case R_HEXAGON_32: !! 348 v = sym->st_value;
130 *location = value; !! 349 base = *location;
131 break; !! 350 r.rel = &r.rel[1];
132 case R_HEXAGON_32_PCREL: <<
133 *location = value - (u <<
134 break; <<
135 case R_HEXAGON_PLT_B22_PCREL: <<
136 case R_HEXAGON_GOTOFF_LO16: <<
137 case R_HEXAGON_GOTOFF_HI16: <<
138 printk(KERN_ERR "%s: G <<
139 module->name); <<
140 return -ENOEXEC; <<
141 default: <<
142 printk(KERN_ERR "%s: u <<
143 module->name, <<
144 ELF32_R_TYPE(re <<
145 return -ENOEXEC; <<
146 } 351 }
>> 352
>> 353 err = reloc_handler(type, me, location, base, v, rela);
>> 354 if (err)
>> 355 goto out;
>> 356 }
>> 357
>> 358 out:
>> 359 /*
>> 360 * Normally the hi16 list should be deallocated at this point. A
>> 361 * malformed binary however could contain a series of R_MIPS_HI16
>> 362 * relocations not followed by a R_MIPS_LO16 relocation, or if we hit
>> 363 * an error processing a reloc we might have gotten here before
>> 364 * reaching the R_MIPS_LO16. In either case, free up the list and
>> 365 * return an error.
>> 366 */
>> 367 if (me->arch.r_mips_hi16_list) {
>> 368 free_relocation_chain(me->arch.r_mips_hi16_list);
>> 369 me->arch.r_mips_hi16_list = NULL;
>> 370 err = err ?: -ENOEXEC;
>> 371 }
>> 372
>> 373 return err;
>> 374 }
>> 375
>> 376 int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
>> 377 unsigned int symindex, unsigned int relsec,
>> 378 struct module *me)
>> 379 {
>> 380 return __apply_relocate(sechdrs, strtab, symindex, relsec, me, false);
>> 381 }
>> 382
>> 383 #ifdef CONFIG_MODULES_USE_ELF_RELA
>> 384 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
>> 385 unsigned int symindex, unsigned int relsec,
>> 386 struct module *me)
>> 387 {
>> 388 return __apply_relocate(sechdrs, strtab, symindex, relsec, me, true);
>> 389 }
>> 390 #endif /* CONFIG_MODULES_USE_ELF_RELA */
>> 391
>> 392 /* Given an address, look for it in the module exception tables. */
>> 393 const struct exception_table_entry *search_module_dbetables(unsigned long addr)
>> 394 {
>> 395 unsigned long flags;
>> 396 const struct exception_table_entry *e = NULL;
>> 397 struct mod_arch_specific *dbe;
>> 398
>> 399 spin_lock_irqsave(&dbe_lock, flags);
>> 400 list_for_each_entry(dbe, &dbe_list, dbe_list) {
>> 401 e = search_extable(dbe->dbe_start,
>> 402 dbe->dbe_end - dbe->dbe_start, addr);
>> 403 if (e)
>> 404 break;
>> 405 }
>> 406 spin_unlock_irqrestore(&dbe_lock, flags);
>> 407
>> 408 /* Now, if we found one, we are running inside it now, hence
>> 409 we cannot unload the module, hence no refcnt needed. */
>> 410 return e;
>> 411 }
>> 412
>> 413 /* Put in dbe list if necessary. */
>> 414 int module_finalize(const Elf_Ehdr *hdr,
>> 415 const Elf_Shdr *sechdrs,
>> 416 struct module *me)
>> 417 {
>> 418 const Elf_Shdr *s;
>> 419 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
>> 420
>> 421 if (IS_ENABLED(CONFIG_JUMP_LABEL))
>> 422 jump_label_apply_nops(me);
>> 423
>> 424 INIT_LIST_HEAD(&me->arch.dbe_list);
>> 425 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
>> 426 if (strcmp("__dbe_table", secstrings + s->sh_name) != 0)
>> 427 continue;
>> 428 me->arch.dbe_start = (void *)s->sh_addr;
>> 429 me->arch.dbe_end = (void *)s->sh_addr + s->sh_size;
>> 430 spin_lock_irq(&dbe_lock);
>> 431 list_add(&me->arch.dbe_list, &dbe_list);
>> 432 spin_unlock_irq(&dbe_lock);
147 } 433 }
148 return 0; 434 return 0;
>> 435 }
>> 436
>> 437 void module_arch_cleanup(struct module *mod)
>> 438 {
>> 439 spin_lock_irq(&dbe_lock);
>> 440 list_del(&mod->arch.dbe_list);
>> 441 spin_unlock_irq(&dbe_lock);
149 } 442 }
150 443
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