1 // SPDX-License-Identifier: GPL-2.0-or-later !! 1 /* Kernel module help for Alpha.
2 /* !! 2 Copyright (C) 2002 Richard Henderson.
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 */
13 #include <linux/moduleloader.h> 18 #include <linux/moduleloader.h>
14 #include <linux/elf.h> 19 #include <linux/elf.h>
>> 20 #include <linux/vmalloc.h>
>> 21 #include <linux/fs.h>
>> 22 #include <linux/string.h>
>> 23 #include <linux/kernel.h>
>> 24 #include <linux/slab.h>
>> 25
>> 26 #if 0
>> 27 #define DEBUGP printk
>> 28 #else
>> 29 #define DEBUGP(fmt...)
>> 30 #endif
>> 31
>> 32 /* Allocate the GOT at the end of the core sections. */
>> 33
>> 34 struct got_entry {
>> 35 struct got_entry *next;
>> 36 Elf64_Sxword r_addend;
>> 37 int got_offset;
>> 38 };
>> 39
>> 40 static inline void
>> 41 process_reloc_for_got(Elf64_Rela *rela,
>> 42 struct got_entry *chains, Elf64_Xword *poffset)
>> 43 {
>> 44 unsigned long r_sym = ELF64_R_SYM (rela->r_info);
>> 45 unsigned long r_type = ELF64_R_TYPE (rela->r_info);
>> 46 Elf64_Sxword r_addend = rela->r_addend;
>> 47 struct got_entry *g;
>> 48
>> 49 if (r_type != R_ALPHA_LITERAL)
>> 50 return;
>> 51
>> 52 for (g = chains + r_sym; g ; g = g->next)
>> 53 if (g->r_addend == r_addend) {
>> 54 if (g->got_offset == 0) {
>> 55 g->got_offset = *poffset;
>> 56 *poffset += 8;
>> 57 }
>> 58 goto found_entry;
>> 59 }
>> 60
>> 61 g = kmalloc (sizeof (*g), GFP_KERNEL);
>> 62 g->next = chains[r_sym].next;
>> 63 g->r_addend = r_addend;
>> 64 g->got_offset = *poffset;
>> 65 *poffset += 8;
>> 66 chains[r_sym].next = g;
>> 67
>> 68 found_entry:
>> 69 /* Trick: most of the ELF64_R_TYPE field is unused. There are
>> 70 42 valid relocation types, and a 32-bit field. Co-opt the
>> 71 bits above 256 to store the got offset for this reloc. */
>> 72 rela->r_info |= g->got_offset << 8;
>> 73 }
>> 74
>> 75 int
>> 76 module_frob_arch_sections(Elf64_Ehdr *hdr, Elf64_Shdr *sechdrs,
>> 77 char *secstrings, struct module *me)
>> 78 {
>> 79 struct got_entry *chains;
>> 80 Elf64_Rela *rela;
>> 81 Elf64_Shdr *esechdrs, *symtab, *s, *got;
>> 82 unsigned long nsyms, nrela, i;
>> 83
>> 84 esechdrs = sechdrs + hdr->e_shnum;
>> 85 symtab = got = NULL;
>> 86
>> 87 /* Find out how large the symbol table is. Allocate one got_entry
>> 88 head per symbol. Normally this will be enough, but not always.
>> 89 We'll chain different offsets for the symbol down each head. */
>> 90 for (s = sechdrs; s < esechdrs; ++s)
>> 91 if (s->sh_type == SHT_SYMTAB)
>> 92 symtab = s;
>> 93 else if (!strcmp(".got", secstrings + s->sh_name)) {
>> 94 got = s;
>> 95 me->arch.gotsecindex = s - sechdrs;
>> 96 }
>> 97
>> 98 if (!symtab) {
>> 99 printk(KERN_ERR "module %s: no symbol table\n", me->name);
>> 100 return -ENOEXEC;
>> 101 }
>> 102 if (!got) {
>> 103 printk(KERN_ERR "module %s: no got section\n", me->name);
>> 104 return -ENOEXEC;
>> 105 }
>> 106
>> 107 nsyms = symtab->sh_size / sizeof(Elf64_Sym);
>> 108 chains = kcalloc(nsyms, sizeof(struct got_entry), GFP_KERNEL);
>> 109 if (!chains) {
>> 110 printk(KERN_ERR
>> 111 "module %s: no memory for symbol chain buffer\n",
>> 112 me->name);
>> 113 return -ENOMEM;
>> 114 }
>> 115
>> 116 got->sh_size = 0;
>> 117 got->sh_addralign = 8;
>> 118 got->sh_type = SHT_NOBITS;
>> 119
>> 120 /* Examine all LITERAL relocations to find out what GOT entries
>> 121 are required. This sizes the GOT section as well. */
>> 122 for (s = sechdrs; s < esechdrs; ++s)
>> 123 if (s->sh_type == SHT_RELA) {
>> 124 nrela = s->sh_size / sizeof(Elf64_Rela);
>> 125 rela = (void *)hdr + s->sh_offset;
>> 126 for (i = 0; i < nrela; ++i)
>> 127 process_reloc_for_got(rela+i, chains,
>> 128 &got->sh_size);
>> 129 }
>> 130
>> 131 /* Free the memory we allocated. */
>> 132 for (i = 0; i < nsyms; ++i) {
>> 133 struct got_entry *g, *n;
>> 134 for (g = chains[i].next; g ; g = n) {
>> 135 n = g->next;
>> 136 kfree(g);
>> 137 }
>> 138 }
>> 139 kfree(chains);
15 140
16 int apply_relocate_add(Elf32_Shdr *sechdrs, !! 141 return 0;
17 const char *strtab, !! 142 }
18 unsigned int symindex, !! 143
19 unsigned int relsec, !! 144 int
20 struct module *me) !! 145 apply_relocate_add(Elf64_Shdr *sechdrs, const char *strtab,
>> 146 unsigned int symindex, unsigned int relsec,
>> 147 struct module *me)
21 { 148 {
22 unsigned int i; !! 149 Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr;
23 Elf32_Rela *rel = (void *)sechdrs[rels !! 150 unsigned long i, n = sechdrs[relsec].sh_size / sizeof(*rela);
24 Elf32_Sym *sym; !! 151 Elf64_Sym *symtab, *sym;
25 uint32_t *location; !! 152 void *base, *location;
26 uint32_t value; !! 153 unsigned long got, gp;
27 !! 154
28 pr_debug("Applying relocate section %u !! 155 DEBUGP("Applying relocate section %u to %u\n", relsec,
29 sechdrs[relsec].sh_info); !! 156 sechdrs[relsec].sh_info);
30 for (i = 0; i < sechdrs[relsec].sh_siz !! 157
31 /* This is where to make the c !! 158 base = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr;
32 location = (void *)sechdrs[sec !! 159 symtab = (Elf64_Sym *)sechdrs[symindex].sh_addr;
33 + rel[i].r_offset; !! 160
>> 161 /* The small sections were sorted to the end of the segment.
>> 162 The following should definitely cover them. */
>> 163 gp = (u64)me->module_core + me->core_size - 0x8000;
>> 164 got = sechdrs[me->arch.gotsecindex].sh_addr;
>> 165
>> 166 for (i = 0; i < n; i++) {
>> 167 unsigned long r_sym = ELF64_R_SYM (rela[i].r_info);
>> 168 unsigned long r_type = ELF64_R_TYPE (rela[i].r_info);
>> 169 unsigned long r_got_offset = r_type >> 8;
>> 170 unsigned long value, hi, lo;
>> 171 r_type &= 0xff;
>> 172
>> 173 /* This is where to make the change. */
>> 174 location = base + rela[i].r_offset;
34 175
35 /* This is the symbol it is re 176 /* This is the symbol it is referring to. Note that all
36 undefined symbols have been !! 177 unresolved symbols have been resolved. */
37 sym = (Elf32_Sym *)sechdrs[sym !! 178 sym = symtab + r_sym;
38 + ELF32_R_SYM(rel[i].r !! 179 value = sym->st_value + rela[i].r_addend;
39 value = sym->st_value + rel[i] !! 180
40 !! 181 switch (r_type) {
41 switch (ELF32_R_TYPE(rel[i].r_ !! 182 case R_ALPHA_NONE:
42 case R_OR1K_32: <<
43 *location = value; <<
44 break; <<
45 case R_OR1K_LO_16_IN_INSN: <<
46 *((uint16_t *)location <<
47 break; <<
48 case R_OR1K_HI_16_IN_INSN: <<
49 *((uint16_t *)location <<
50 break; <<
51 case R_OR1K_INSN_REL_26: <<
52 value -= (uint32_t)loc <<
53 value >>= 2; <<
54 value &= 0x03ffffff; <<
55 value |= *location & 0 <<
56 *location = value; <<
57 break; <<
58 case R_OR1K_AHI16: <<
59 /* Adjust the operand <<
60 value += 0x8000; <<
61 *((uint16_t *)location <<
62 break; <<
63 case R_OR1K_SLO16: <<
64 /* Split value lower 1 <<
65 value = ((value & 0xf8 <<
66 *location = (*location <<
67 break; 183 break;
68 default: !! 184 case R_ALPHA_REFQUAD:
69 pr_err("module %s: Unk !! 185 /* BUG() can produce misaligned relocations. */
70 me->name, ELF32 !! 186 ((u32 *)location)[0] = value;
>> 187 ((u32 *)location)[1] = value >> 32;
>> 188 break;
>> 189 case R_ALPHA_GPREL32:
>> 190 value -= gp;
>> 191 if ((int)value != value)
>> 192 goto reloc_overflow;
>> 193 *(u32 *)location = value;
>> 194 break;
>> 195 case R_ALPHA_LITERAL:
>> 196 hi = got + r_got_offset;
>> 197 lo = hi - gp;
>> 198 if ((short)lo != lo)
>> 199 goto reloc_overflow;
>> 200 *(u16 *)location = lo;
>> 201 *(u64 *)hi = value;
71 break; 202 break;
>> 203 case R_ALPHA_LITUSE:
>> 204 break;
>> 205 case R_ALPHA_GPDISP:
>> 206 value = gp - (u64)location;
>> 207 lo = (short)value;
>> 208 hi = (int)(value - lo);
>> 209 if (hi + lo != value)
>> 210 goto reloc_overflow;
>> 211 *(u16 *)location = hi >> 16;
>> 212 *(u16 *)(location + rela[i].r_addend) = lo;
>> 213 break;
>> 214 case R_ALPHA_BRSGP:
>> 215 /* BRSGP is only allowed to bind to local symbols.
>> 216 If the section is undef, this means that the
>> 217 value was resolved from somewhere else. */
>> 218 if (sym->st_shndx == SHN_UNDEF)
>> 219 goto reloc_overflow;
>> 220 if ((sym->st_other & STO_ALPHA_STD_GPLOAD) ==
>> 221 STO_ALPHA_STD_GPLOAD)
>> 222 /* Omit the prologue. */
>> 223 value += 8;
>> 224 /* FALLTHRU */
>> 225 case R_ALPHA_BRADDR:
>> 226 value -= (u64)location + 4;
>> 227 if (value & 3)
>> 228 goto reloc_overflow;
>> 229 value = (long)value >> 2;
>> 230 if (value + (1<<21) >= 1<<22)
>> 231 goto reloc_overflow;
>> 232 value &= 0x1fffff;
>> 233 value |= *(u32 *)location & ~0x1fffff;
>> 234 *(u32 *)location = value;
>> 235 break;
>> 236 case R_ALPHA_HINT:
>> 237 break;
>> 238 case R_ALPHA_SREL32:
>> 239 value -= (u64)location;
>> 240 if ((int)value != value)
>> 241 goto reloc_overflow;
>> 242 *(u32 *)location = value;
>> 243 break;
>> 244 case R_ALPHA_SREL64:
>> 245 value -= (u64)location;
>> 246 *(u64 *)location = value;
>> 247 break;
>> 248 case R_ALPHA_GPRELHIGH:
>> 249 value = (long)(value - gp + 0x8000) >> 16;
>> 250 if ((short) value != value)
>> 251 goto reloc_overflow;
>> 252 *(u16 *)location = value;
>> 253 break;
>> 254 case R_ALPHA_GPRELLOW:
>> 255 value -= gp;
>> 256 *(u16 *)location = value;
>> 257 break;
>> 258 case R_ALPHA_GPREL16:
>> 259 value -= gp;
>> 260 if ((short) value != value)
>> 261 goto reloc_overflow;
>> 262 *(u16 *)location = value;
>> 263 break;
>> 264 default:
>> 265 printk(KERN_ERR "module %s: Unknown relocation: %lu\n",
>> 266 me->name, r_type);
>> 267 return -ENOEXEC;
>> 268 reloc_overflow:
>> 269 if (ELF64_ST_TYPE (sym->st_info) == STT_SECTION)
>> 270 printk(KERN_ERR
>> 271 "module %s: Relocation (type %lu) overflow vs section %d\n",
>> 272 me->name, r_type, sym->st_shndx);
>> 273 else
>> 274 printk(KERN_ERR
>> 275 "module %s: Relocation (type %lu) overflow vs %s\n",
>> 276 me->name, r_type, strtab + sym->st_name);
>> 277 return -ENOEXEC;
72 } 278 }
73 } 279 }
74 280
75 return 0; 281 return 0;
76 } 282 }
77 283
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