1 // SPDX-License-Identifier: GPL-2.0-or-later !! 1 /* Kernel module help for PPC.
2 /* !! 2 Copyright (C) 2001 Rusty Russell.
3 * OpenRISC module.c <<
4 * <<
5 * Linux architectural port borrowing liberall <<
6 * others. All original copyrights apply as p <<
7 * declaration. <<
8 * <<
9 * Modifications for the OpenRISC architecture <<
10 * Copyright (C) 2010-2011 Jonas Bonn <jonas@s <<
11 */ <<
12 3
>> 4 This program is free software; you can redistribute it and/or modify
>> 5 it under the terms of the GNU General Public License as published by
>> 6 the Free Software Foundation; either version 2 of the License, or
>> 7 (at your option) any later version.
>> 8
>> 9 This program is distributed in the hope that it will be useful,
>> 10 but WITHOUT ANY WARRANTY; without even the implied warranty of
>> 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> 12 GNU General Public License for more details.
>> 13
>> 14 You should have received a copy of the GNU General Public License
>> 15 along with this program; if not, write to the Free Software
>> 16 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
>> 17 */
>> 18 #include <linux/module.h>
13 #include <linux/moduleloader.h> 19 #include <linux/moduleloader.h>
14 #include <linux/elf.h> 20 #include <linux/elf.h>
>> 21 #include <linux/vmalloc.h>
>> 22 #include <linux/fs.h>
>> 23 #include <linux/string.h>
>> 24 #include <linux/kernel.h>
>> 25 #include <linux/cache.h>
>> 26
>> 27 #if 0
>> 28 #define DEBUGP printk
>> 29 #else
>> 30 #define DEBUGP(fmt , ...)
>> 31 #endif
>> 32
>> 33 LIST_HEAD(module_bug_list);
>> 34
>> 35 void *module_alloc(unsigned long size)
>> 36 {
>> 37 if (size == 0)
>> 38 return NULL;
>> 39 return vmalloc(size);
>> 40 }
>> 41
>> 42 /* Free memory returned from module_alloc */
>> 43 void module_free(struct module *mod, void *module_region)
>> 44 {
>> 45 vfree(module_region);
>> 46 /* FIXME: If module_region == mod->init_region, trim exception
>> 47 table entries. */
>> 48 }
>> 49
>> 50 /* Count how many different relocations (different symbol, different
>> 51 addend) */
>> 52 static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num)
>> 53 {
>> 54 unsigned int i, j, ret = 0;
>> 55
>> 56 /* Sure, this is order(n^2), but it's usually short, and not
>> 57 time critical */
>> 58 for (i = 0; i < num; i++) {
>> 59 for (j = 0; j < i; j++) {
>> 60 /* If this addend appeared before, it's
>> 61 already been counted */
>> 62 if (ELF32_R_SYM(rela[i].r_info)
>> 63 == ELF32_R_SYM(rela[j].r_info)
>> 64 && rela[i].r_addend == rela[j].r_addend)
>> 65 break;
>> 66 }
>> 67 if (j == i) ret++;
>> 68 }
>> 69 return ret;
>> 70 }
>> 71
>> 72 /* Get the potential trampolines size required of the init and
>> 73 non-init sections */
>> 74 static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
>> 75 const Elf32_Shdr *sechdrs,
>> 76 const char *secstrings,
>> 77 int is_init)
>> 78 {
>> 79 unsigned long ret = 0;
>> 80 unsigned i;
>> 81
>> 82 /* Everything marked ALLOC (this includes the exported
>> 83 symbols) */
>> 84 for (i = 1; i < hdr->e_shnum; i++) {
>> 85 /* If it's called *.init*, and we're not init, we're
>> 86 not interested */
>> 87 if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != 0)
>> 88 != is_init)
>> 89 continue;
>> 90
>> 91 if (sechdrs[i].sh_type == SHT_RELA) {
>> 92 DEBUGP("Found relocations in section %u\n", i);
>> 93 DEBUGP("Ptr: %p. Number: %u\n",
>> 94 (void *)hdr + sechdrs[i].sh_offset,
>> 95 sechdrs[i].sh_size / sizeof(Elf32_Rela));
>> 96 ret += count_relocs((void *)hdr
>> 97 + sechdrs[i].sh_offset,
>> 98 sechdrs[i].sh_size
>> 99 / sizeof(Elf32_Rela))
>> 100 * sizeof(struct ppc_plt_entry);
>> 101 }
>> 102 }
>> 103
>> 104 return ret;
>> 105 }
>> 106
>> 107 int module_frob_arch_sections(Elf32_Ehdr *hdr,
>> 108 Elf32_Shdr *sechdrs,
>> 109 char *secstrings,
>> 110 struct module *me)
>> 111 {
>> 112 unsigned int i;
>> 113
>> 114 /* Find .plt and .init.plt sections */
>> 115 for (i = 0; i < hdr->e_shnum; i++) {
>> 116 if (strcmp(secstrings + sechdrs[i].sh_name, ".init.plt") == 0)
>> 117 me->arch.init_plt_section = i;
>> 118 else if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0)
>> 119 me->arch.core_plt_section = i;
>> 120 }
>> 121 if (!me->arch.core_plt_section || !me->arch.init_plt_section) {
>> 122 printk("Module doesn't contain .plt or .init.plt sections.\n");
>> 123 return -ENOEXEC;
>> 124 }
>> 125
>> 126 /* Override their sizes */
>> 127 sechdrs[me->arch.core_plt_section].sh_size
>> 128 = get_plt_size(hdr, sechdrs, secstrings, 0);
>> 129 sechdrs[me->arch.init_plt_section].sh_size
>> 130 = get_plt_size(hdr, sechdrs, secstrings, 1);
>> 131 return 0;
>> 132 }
>> 133
>> 134 int apply_relocate(Elf32_Shdr *sechdrs,
>> 135 const char *strtab,
>> 136 unsigned int symindex,
>> 137 unsigned int relsec,
>> 138 struct module *module)
>> 139 {
>> 140 printk(KERN_ERR "%s: Non-ADD RELOCATION unsupported\n",
>> 141 module->name);
>> 142 return -ENOEXEC;
>> 143 }
>> 144
>> 145 static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val)
>> 146 {
>> 147 if (entry->jump[0] == 0x3d600000 + ((val + 0x8000) >> 16)
>> 148 && entry->jump[1] == 0x396b0000 + (val & 0xffff))
>> 149 return 1;
>> 150 return 0;
>> 151 }
>> 152
>> 153 /* Set up a trampoline in the PLT to bounce us to the distant function */
>> 154 static uint32_t do_plt_call(void *location,
>> 155 Elf32_Addr val,
>> 156 Elf32_Shdr *sechdrs,
>> 157 struct module *mod)
>> 158 {
>> 159 struct ppc_plt_entry *entry;
>> 160
>> 161 DEBUGP("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location);
>> 162 /* Init, or core PLT? */
>> 163 if (location >= mod->module_core
>> 164 && location < mod->module_core + mod->core_size)
>> 165 entry = (void *)sechdrs[mod->arch.core_plt_section].sh_addr;
>> 166 else
>> 167 entry = (void *)sechdrs[mod->arch.init_plt_section].sh_addr;
>> 168
>> 169 /* Find this entry, or if that fails, the next avail. entry */
>> 170 while (entry->jump[0]) {
>> 171 if (entry_matches(entry, val)) return (uint32_t)entry;
>> 172 entry++;
>> 173 }
>> 174
>> 175 /* Stolen from Paul Mackerras as well... */
>> 176 entry->jump[0] = 0x3d600000+((val+0x8000)>>16); /* lis r11,sym@ha */
>> 177 entry->jump[1] = 0x396b0000 + (val&0xffff); /* addi r11,r11,sym@l*/
>> 178 entry->jump[2] = 0x7d6903a6; /* mtctr r11 */
>> 179 entry->jump[3] = 0x4e800420; /* bctr */
>> 180
>> 181 DEBUGP("Initialized plt for 0x%x at %p\n", val, entry);
>> 182 return (uint32_t)entry;
>> 183 }
15 184
16 int apply_relocate_add(Elf32_Shdr *sechdrs, 185 int apply_relocate_add(Elf32_Shdr *sechdrs,
17 const char *strtab, 186 const char *strtab,
18 unsigned int symindex, 187 unsigned int symindex,
19 unsigned int relsec, 188 unsigned int relsec,
20 struct module *me) !! 189 struct module *module)
21 { 190 {
22 unsigned int i; 191 unsigned int i;
23 Elf32_Rela *rel = (void *)sechdrs[rels !! 192 Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
24 Elf32_Sym *sym; 193 Elf32_Sym *sym;
25 uint32_t *location; 194 uint32_t *location;
26 uint32_t value; 195 uint32_t value;
27 196
28 pr_debug("Applying relocate section %u !! 197 DEBUGP("Applying ADD relocate section %u to %u\n", relsec,
29 sechdrs[relsec].sh_info); !! 198 sechdrs[relsec].sh_info);
30 for (i = 0; i < sechdrs[relsec].sh_siz !! 199 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
31 /* This is where to make the c 200 /* This is where to make the change */
32 location = (void *)sechdrs[sec 201 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
33 + rel[i].r_offset; !! 202 + rela[i].r_offset;
34 <<
35 /* This is the symbol it is re 203 /* This is the symbol it is referring to. Note that all
36 undefined symbols have been 204 undefined symbols have been resolved. */
37 sym = (Elf32_Sym *)sechdrs[sym 205 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
38 + ELF32_R_SYM(rel[i].r !! 206 + ELF32_R_SYM(rela[i].r_info);
39 value = sym->st_value + rel[i] !! 207 /* `Everything is relative'. */
>> 208 value = sym->st_value + rela[i].r_addend;
40 209
41 switch (ELF32_R_TYPE(rel[i].r_ !! 210 switch (ELF32_R_TYPE(rela[i].r_info)) {
42 case R_OR1K_32: !! 211 case R_PPC_ADDR32:
43 *location = value; !! 212 /* Simply set it */
44 break; !! 213 *(uint32_t *)location = value;
45 case R_OR1K_LO_16_IN_INSN: <<
46 *((uint16_t *)location <<
47 break; 214 break;
48 case R_OR1K_HI_16_IN_INSN: !! 215
49 *((uint16_t *)location !! 216 case R_PPC_ADDR16_LO:
>> 217 /* Low half of the symbol */
>> 218 *(uint16_t *)location = value;
50 break; 219 break;
51 case R_OR1K_INSN_REL_26: !! 220
52 value -= (uint32_t)loc !! 221 case R_PPC_ADDR16_HA:
53 value >>= 2; !! 222 /* Sign-adjusted lower 16 bits: PPC ELF ABI says:
54 value &= 0x03ffffff; !! 223 (((x >> 16) + ((x & 0x8000) ? 1 : 0))) & 0xFFFF.
55 value |= *location & 0 !! 224 This is the same, only sane.
56 *location = value; !! 225 */
>> 226 *(uint16_t *)location = (value + 0x8000) >> 16;
57 break; 227 break;
58 case R_OR1K_AHI16: !! 228
59 /* Adjust the operand !! 229 case R_PPC_REL24:
60 value += 0x8000; !! 230 if ((int)(value - (uint32_t)location) < -0x02000000
61 *((uint16_t *)location !! 231 || (int)(value - (uint32_t)location) >= 0x02000000)
>> 232 value = do_plt_call(location, value,
>> 233 sechdrs, module);
>> 234
>> 235 /* Only replace bits 2 through 26 */
>> 236 DEBUGP("REL24 value = %08X. location = %08X\n",
>> 237 value, (uint32_t)location);
>> 238 DEBUGP("Location before: %08X.\n",
>> 239 *(uint32_t *)location);
>> 240 *(uint32_t *)location
>> 241 = (*(uint32_t *)location & ~0x03fffffc)
>> 242 | ((value - (uint32_t)location)
>> 243 & 0x03fffffc);
>> 244 DEBUGP("Location after: %08X.\n",
>> 245 *(uint32_t *)location);
>> 246 DEBUGP("ie. jump to %08X+%08X = %08X\n",
>> 247 *(uint32_t *)location & 0x03fffffc,
>> 248 (uint32_t)location,
>> 249 (*(uint32_t *)location & 0x03fffffc)
>> 250 + (uint32_t)location);
62 break; 251 break;
63 case R_OR1K_SLO16: !! 252
64 /* Split value lower 1 !! 253 case R_PPC_REL32:
65 value = ((value & 0xf8 !! 254 /* 32-bit relative jump. */
66 *location = (*location !! 255 *(uint32_t *)location = value - (uint32_t)location;
67 break; 256 break;
>> 257
68 default: 258 default:
69 pr_err("module %s: Unk !! 259 printk("%s: unknown ADD relocation: %u\n",
70 me->name, ELF32 !! 260 module->name,
71 break; !! 261 ELF32_R_TYPE(rela[i].r_info));
>> 262 return -ENOEXEC;
72 } 263 }
73 } 264 }
>> 265 return 0;
>> 266 }
>> 267
>> 268 /* FIXME: Sort exception table --RR */
>> 269 int module_finalize(const Elf_Ehdr *hdr,
>> 270 const Elf_Shdr *sechdrs,
>> 271 struct module *me)
>> 272 {
>> 273 char *secstrings;
>> 274 unsigned int i;
>> 275
>> 276 me->arch.bug_table = NULL;
>> 277 me->arch.num_bugs = 0;
>> 278
>> 279 /* Find the __bug_table section, if present */
>> 280 secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
>> 281 for (i = 1; i < hdr->e_shnum; i++) {
>> 282 if (strcmp(secstrings+sechdrs[i].sh_name, "__bug_table"))
>> 283 continue;
>> 284 me->arch.bug_table = (void *) sechdrs[i].sh_addr;
>> 285 me->arch.num_bugs = sechdrs[i].sh_size / sizeof(struct bug_entry);
>> 286 break;
>> 287 }
>> 288
>> 289 /*
>> 290 * Strictly speaking this should have a spinlock to protect against
>> 291 * traversals, but since we only traverse on BUG()s, a spinlock
>> 292 * could potentially lead to deadlock and thus be counter-productive.
>> 293 */
>> 294 list_add(&me->arch.bug_list, &module_bug_list);
74 295
75 return 0; 296 return 0;
>> 297 }
>> 298
>> 299 void module_arch_cleanup(struct module *mod)
>> 300 {
>> 301 list_del(&mod->arch.bug_list);
>> 302 }
>> 303
>> 304 struct bug_entry *module_find_bug(unsigned long bugaddr)
>> 305 {
>> 306 struct mod_arch_specific *mod;
>> 307 unsigned int i;
>> 308 struct bug_entry *bug;
>> 309
>> 310 list_for_each_entry(mod, &module_bug_list, bug_list) {
>> 311 bug = mod->bug_table;
>> 312 for (i = 0; i < mod->num_bugs; ++i, ++bug)
>> 313 if (bugaddr == bug->bug_addr)
>> 314 return bug;
>> 315 }
>> 316 return NULL;
76 } 317 }
77 318
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