release/src-rt-6.x.4708/linux/linux-2.6.36/arch/alpha/kernel/module.c

   1 /*  Kernel module help for Alpha.
   2     Copyright (C) 2002 Richard Henderson.
   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/moduleloader.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 #define DEBUGP(fmt...)
  27
  28 void *
  29 module_alloc(unsigned long size)
  30 {
  31         if (size == 0)
  32                 return NULL;
  33         return vmalloc(size);
  34 }
  35
  36 void
  37 module_free(struct module *mod, void *module_region)
  38 {
  39         vfree(module_region);
  40 }
  41
  42 /* Allocate the GOT at the end of the core sections.  */
  43
  44 struct got_entry {
  45         struct got_entry *next;
  46         Elf64_Sxword r_addend;
  47         int got_offset;
  48 };
  49
  50 static inline void
  51 process_reloc_for_got(Elf64_Rela *rela,
  52                       struct got_entry *chains, Elf64_Xword *poffset)
  53 {
  54         unsigned long r_sym = ELF64_R_SYM (rela->r_info);
  55         unsigned long r_type = ELF64_R_TYPE (rela->r_info);
  56         Elf64_Sxword r_addend = rela->r_addend;
  57         struct got_entry *g;
  58
  59         if (r_type != R_ALPHA_LITERAL)
  60                 return;
  61
  62         for (g = chains + r_sym; g ; g = g->next)
  63                 if (g->r_addend == r_addend) {
  64                         if (g->got_offset == 0) {
  65                                 g->got_offset = *poffset;
  66                                 *poffset += 8;
  67                         }
  68                         goto found_entry;
  69                 }
  70
  71         g = kmalloc (sizeof (*g), GFP_KERNEL);
  72         g->next = chains[r_sym].next;
  73         g->r_addend = r_addend;
  74         g->got_offset = *poffset;
  75         *poffset += 8;
  76         chains[r_sym].next = g;
  77
  78  found_entry:
  79         /* Trick: most of the ELF64_R_TYPE field is unused.  There are
  80            42 valid relocation types, and a 32-bit field.  Co-opt the
  81            bits above 256 to store the got offset for this reloc.  */
  82         rela->r_info |= g->got_offset << 8;
  83 }
  84
  85 int
  86 module_frob_arch_sections(Elf64_Ehdr *hdr, Elf64_Shdr *sechdrs,
  87                           char *secstrings, struct module *me)
  88 {
  89         struct got_entry *chains;
  90         Elf64_Rela *rela;
  91         Elf64_Shdr *esechdrs, *symtab, *s, *got;
  92         unsigned long nsyms, nrela, i;
  93
  94         esechdrs = sechdrs + hdr->e_shnum;
  95         symtab = got = NULL;
  96
  97         /* Find out how large the symbol table is.  Allocate one got_entry
  98            head per symbol.  Normally this will be enough, but not always.
  99            We'll chain different offsets for the symbol down each head.  */
 100         for (s = sechdrs; s < esechdrs; ++s)
 101                 if (s->sh_type == SHT_SYMTAB)
 102                         symtab = s;
 103                 else if (!strcmp(".got", secstrings + s->sh_name)) {
 104                         got = s;
 105                         me->arch.gotsecindex = s - sechdrs;
 106                 }
 107
 108         if (!symtab) {
 109                 printk(KERN_ERR "module %s: no symbol table\n", me->name);
 110                 return -ENOEXEC;
 111         }
 112         if (!got) {
 113                 printk(KERN_ERR "module %s: no got section\n", me->name);
 114                 return -ENOEXEC;
 115         }
 116
 117         nsyms = symtab->sh_size / sizeof(Elf64_Sym);
 118         chains = kcalloc(nsyms, sizeof(struct got_entry), GFP_KERNEL);
 119         if (!chains) {
 120                 printk(KERN_ERR
 121                        "module %s: no memory for symbol chain buffer\n",
 122                        me->name);
 123                 return -ENOMEM;
 124         }
 125
 126         got->sh_size = 0;
 127         got->sh_addralign = 8;
 128         got->sh_type = SHT_NOBITS;
 129
 130         /* Examine all LITERAL relocations to find out what GOT entries
 131            are required.  This sizes the GOT section as well.  */
 132         for (s = sechdrs; s < esechdrs; ++s)
 133                 if (s->sh_type == SHT_RELA) {
 134                         nrela = s->sh_size / sizeof(Elf64_Rela);
 135                         rela = (void *)hdr + s->sh_offset;
 136                         for (i = 0; i < nrela; ++i)
 137                                 process_reloc_for_got(rela+i, chains,
 138                                                       &got->sh_size);
 139                 }
 140
 141         /* Free the memory we allocated.  */
 142         for (i = 0; i < nsyms; ++i) {
 143                 struct got_entry *g, *n;
 144                 for (g = chains[i].next; g ; g = n) {
 145                         n = g->next;
 146                         kfree(g);
 147                 }
 148         }
 149         kfree(chains);
 150
 151         return 0;
 152 }
 153
 154 int
 155 apply_relocate(Elf64_Shdr *sechdrs, const char *strtab, unsigned int symindex,
 156                unsigned int relsec, struct module *me)
 157 {
 158         printk(KERN_ERR "module %s: REL relocation unsupported\n", me->name);
 159         return -ENOEXEC;
 160 }
 161
 162 int
 163 apply_relocate_add(Elf64_Shdr *sechdrs, const char *strtab,
 164                    unsigned int symindex, unsigned int relsec,
 165                    struct module *me)
 166 {
 167         Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr;
 168         unsigned long i, n = sechdrs[relsec].sh_size / sizeof(*rela);
 169         Elf64_Sym *symtab, *sym;
 170         void *base, *location;
 171         unsigned long got, gp;
 172
 173         DEBUGP("Applying relocate section %u to %u\n", relsec,
 174                sechdrs[relsec].sh_info);
 175
 176         base = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr;
 177         symtab = (Elf64_Sym *)sechdrs[symindex].sh_addr;
 178
 179         /* The small sections were sorted to the end of the segment.
 180            The following should definitely cover them.  */
 181         gp = (u64)me->module_core + me->core_size - 0x8000;
 182         got = sechdrs[me->arch.gotsecindex].sh_addr;
 183
 184         for (i = 0; i < n; i++) {
 185                 unsigned long r_sym = ELF64_R_SYM (rela[i].r_info);
 186                 unsigned long r_type = ELF64_R_TYPE (rela[i].r_info);
 187                 unsigned long r_got_offset = r_type >> 8;
 188                 unsigned long value, hi, lo;
 189                 r_type &= 0xff;
 190
 191                 /* This is where to make the change.  */
 192                 location = base + rela[i].r_offset;
 193
 194                 /* This is the symbol it is referring to.  Note that all
 195                    unresolved symbols have been resolved.  */
 196                 sym = symtab + r_sym;
 197                 value = sym->st_value + rela[i].r_addend;
 198
 199                 switch (r_type) {
 200                 case R_ALPHA_NONE:
 201                         break;
 202                 case R_ALPHA_REFQUAD:
 203                         /* BUG() can produce misaligned relocations. */
 204                         ((u32 *)location)[0] = value;
 205                         ((u32 *)location)[1] = value >> 32;
 206                         break;
 207                 case R_ALPHA_GPREL32:
 208                         value -= gp;
 209                         if ((int)value != value)
 210                                 goto reloc_overflow;
 211                         *(u32 *)location = value;
 212                         break;
 213                 case R_ALPHA_LITERAL:
 214                         hi = got + r_got_offset;
 215                         lo = hi - gp;
 216                         if ((short)lo != lo)
 217                                 goto reloc_overflow;
 218                         *(u16 *)location = lo;
 219                         *(u64 *)hi = value;
 220                         break;
 221                 case R_ALPHA_LITUSE:
 222                         break;
 223                 case R_ALPHA_GPDISP:
 224                         value = gp - (u64)location;
 225                         lo = (short)value;
 226                         hi = (int)(value - lo);
 227                         if (hi + lo != value)
 228                                 goto reloc_overflow;
 229                         *(u16 *)location = hi >> 16;
 230                         *(u16 *)(location + rela[i].r_addend) = lo;
 231                         break;
 232                 case R_ALPHA_BRSGP:
 233                         /* BRSGP is only allowed to bind to local symbols.
 234                            If the section is undef, this means that the
 235                            value was resolved from somewhere else.  */
 236                         if (sym->st_shndx == SHN_UNDEF)
 237                                 goto reloc_overflow;
 238                         if ((sym->st_other & STO_ALPHA_STD_GPLOAD) ==
 239                             STO_ALPHA_STD_GPLOAD)
 240                                 /* Omit the prologue. */
 241                                 value += 8;
 242                         /* FALLTHRU */
 243                 case R_ALPHA_BRADDR:
 244                         value -= (u64)location + 4;
 245                         if (value & 3)
 246                                 goto reloc_overflow;
 247                         value = (long)value >> 2;
 248                         if (value + (1<<21) >= 1<<22)
 249                                 goto reloc_overflow;
 250                         value &= 0x1fffff;
 251                         value |= *(u32 *)location & ~0x1fffff;
 252                         *(u32 *)location = value;
 253                         break;
 254                 case R_ALPHA_HINT:
 255                         break;
 256                 case R_ALPHA_SREL32:
 257                         value -= (u64)location;
 258                         if ((int)value != value)
 259                                 goto reloc_overflow;
 260                         *(u32 *)location = value;
 261                         break;
 262                 case R_ALPHA_SREL64:
 263                         value -= (u64)location;
 264                         *(u64 *)location = value;
 265                         break;
 266                 case R_ALPHA_GPRELHIGH:
 267                         value = (long)(value - gp + 0x8000) >> 16;
 268                         if ((short) value != value)
 269                                 goto reloc_overflow;
 270                         *(u16 *)location = value;
 271                         break;
 272                 case R_ALPHA_GPRELLOW:
 273                         value -= gp;
 274                         *(u16 *)location = value;
 275                         break;
 276                 case R_ALPHA_GPREL16:
 277                         value -= gp;
 278                         if ((short) value != value)
 279                                 goto reloc_overflow;
 280                         *(u16 *)location = value;
 281                         break;
 282                 default:
 283                         printk(KERN_ERR "module %s: Unknown relocation: %lu\n",
 284                                me->name, r_type);
 285                         return -ENOEXEC;
 286                 reloc_overflow:
 287                         if (ELF64_ST_TYPE (sym->st_info) == STT_SECTION)
 288                           printk(KERN_ERR
 289                                  "module %s: Relocation (type %lu) overflow vs section %d\n",
 290                                  me->name, r_type, sym->st_shndx);
 291                         else
 292                           printk(KERN_ERR
 293                                  "module %s: Relocation (type %lu) overflow vs %s\n",
 294                                  me->name, r_type, strtab + sym->st_name);
 295                         return -ENOEXEC;
 296                 }
 297         }
 298
 299         return 0;
 300 }
 301
 302 int
 303 module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
 304                 struct module *me)
 305 {
 306         return 0;
 307 }
 308
 309 void
 310 module_arch_cleanup(struct module *mod)
 311 {
 312 }