arch/xtensa/kernel/module.c

   1 /*
   2  * arch/xtensa/kernel/module.c
   3  *
   4  * Module support.
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License.  See the file "COPYING" in the main directory of this archive
   8  * for more details.
   9  *
  10  * Copyright (C) 2001 - 2006 Tensilica Inc.
  11  *
  12  * Chris Zankel <chris@zankel.net>
  13  *
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/moduleloader.h>
  18 #include <linux/elf.h>
  19 #include <linux/vmalloc.h>
  20 #include <linux/fs.h>
  21 #include <linux/string.h>
  22 #include <linux/kernel.h>
  23 #include <linux/cache.h>
  24
  25 static int
  26 decode_calln_opcode (unsigned char *location)
  27 {
  28 #ifdef __XTENSA_EB__
  29         return (location[0] & 0xf0) == 0x50;
  30 #endif
  31 #ifdef __XTENSA_EL__
  32         return (location[0] & 0xf) == 0x5;
  33 #endif
  34 }
  35
  36 static int
  37 decode_l32r_opcode (unsigned char *location)
  38 {
  39 #ifdef __XTENSA_EB__
  40         return (location[0] & 0xf0) == 0x10;
  41 #endif
  42 #ifdef __XTENSA_EL__
  43         return (location[0] & 0xf) == 0x1;
  44 #endif
  45 }
  46
  47 int apply_relocate_add(Elf32_Shdr *sechdrs,
  48                        const char *strtab,
  49                        unsigned int symindex,
  50                        unsigned int relsec,
  51                        struct module *mod)
  52 {
  53         unsigned int i;
  54         Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
  55         Elf32_Sym *sym;
  56         unsigned char *location;
  57         uint32_t value;
  58
  59         pr_debug("Applying relocate section %u to %u\n", relsec,
  60                  sechdrs[relsec].sh_info);
  61
  62         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
  63                 location = (char *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  64                         + rela[i].r_offset;
  65                 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
  66                         + ELF32_R_SYM(rela[i].r_info);
  67                 value = sym->st_value + rela[i].r_addend;
  68
  69                 switch (ELF32_R_TYPE(rela[i].r_info)) {
  70                 case R_XTENSA_NONE:
  71                 case R_XTENSA_DIFF8:
  72                 case R_XTENSA_DIFF16:
  73                 case R_XTENSA_DIFF32:
  74                 case R_XTENSA_ASM_EXPAND:
  75                         break;
  76
  77                 case R_XTENSA_32:
  78                 case R_XTENSA_PLT:
  79                         *(uint32_t *)location += value;
  80                         break;
  81
  82                 case R_XTENSA_SLOT0_OP:
  83                         if (decode_calln_opcode(location)) {
  84                                 value -= ((unsigned long)location & -4) + 4;
  85                                 if ((value & 3) != 0 ||
  86                                     ((value + (1 << 19)) >> 20) != 0) {
  87                                         pr_err("%s: relocation out of range, "
  88                                                "section %d reloc %d "
  89                                                "sym '%s'\n",
  90                                                mod->name, relsec, i,
  91                                                strtab + sym->st_name);
  92                                         return -ENOEXEC;
  93                                 }
  94                                 value = (signed int)value >> 2;
  95 #ifdef __XTENSA_EB__
  96                                 location[0] = ((location[0] & ~0x3) |
  97                                             ((value >> 16) & 0x3));
  98                                 location[1] = (value >> 8) & 0xff;
  99                                 location[2] = value & 0xff;
 100 #endif
 101 #ifdef __XTENSA_EL__
 102                                 location[0] = ((location[0] & ~0xc0) |
 103                                             ((value << 6) & 0xc0));
 104                                 location[1] = (value >> 2) & 0xff;
 105                                 location[2] = (value >> 10) & 0xff;
 106 #endif
 107                         } else if (decode_l32r_opcode(location)) {
 108                                 value -= (((unsigned long)location + 3) & -4);
 109                                 if ((value & 3) != 0 ||
 110                                     (signed int)value >> 18 != -1) {
 111                                         pr_err("%s: relocation out of range, "
 112                                                "section %d reloc %d "
 113                                                "sym '%s'\n",
 114                                                mod->name, relsec, i,
 115                                                strtab + sym->st_name);
 116                                         return -ENOEXEC;
 117                                 }
 118                                 value = (signed int)value >> 2;
 119
 120 #ifdef __XTENSA_EB__
 121                                 location[1] = (value >> 8) & 0xff;
 122                                 location[2] = value & 0xff;
 123 #endif
 124 #ifdef __XTENSA_EL__
 125                                 location[1] = value & 0xff;
 126                                 location[2] = (value >> 8) & 0xff;
 127 #endif
 128                         }
 129                         /* FIXME: Ignore any other opcodes.  The Xtensa
 130                            assembler currently assumes that the linker will
 131                            always do relaxation and so all PC-relative
 132                            operands need relocations.  (The assembler also
 133                            writes out the tentative PC-relative values,
 134                            assuming no link-time relaxation, so it is usually
 135                            safe to ignore the relocations.)  If the
 136                            assembler's "--no-link-relax" flag can be made to
 137                            work, and if all kernel modules can be assembled
 138                            with that flag, then unexpected relocations could
 139                            be detected here.  */
 140                         break;
 141
 142                 case R_XTENSA_SLOT1_OP:
 143                 case R_XTENSA_SLOT2_OP:
 144                 case R_XTENSA_SLOT3_OP:
 145                 case R_XTENSA_SLOT4_OP:
 146                 case R_XTENSA_SLOT5_OP:
 147                 case R_XTENSA_SLOT6_OP:
 148                 case R_XTENSA_SLOT7_OP:
 149                 case R_XTENSA_SLOT8_OP:
 150                 case R_XTENSA_SLOT9_OP:
 151                 case R_XTENSA_SLOT10_OP:
 152                 case R_XTENSA_SLOT11_OP:
 153                 case R_XTENSA_SLOT12_OP:
 154                 case R_XTENSA_SLOT13_OP:
 155                 case R_XTENSA_SLOT14_OP:
 156                         pr_err("%s: unexpected FLIX relocation: %u\n",
 157                                mod->name,
 158                                ELF32_R_TYPE(rela[i].r_info));
 159                         return -ENOEXEC;
 160
 161                 case R_XTENSA_SLOT0_ALT:
 162                 case R_XTENSA_SLOT1_ALT:
 163                 case R_XTENSA_SLOT2_ALT:
 164                 case R_XTENSA_SLOT3_ALT:
 165                 case R_XTENSA_SLOT4_ALT:
 166                 case R_XTENSA_SLOT5_ALT:
 167                 case R_XTENSA_SLOT6_ALT:
 168                 case R_XTENSA_SLOT7_ALT:
 169                 case R_XTENSA_SLOT8_ALT:
 170                 case R_XTENSA_SLOT9_ALT:
 171                 case R_XTENSA_SLOT10_ALT:
 172                 case R_XTENSA_SLOT11_ALT:
 173                 case R_XTENSA_SLOT12_ALT:
 174                 case R_XTENSA_SLOT13_ALT:
 175                 case R_XTENSA_SLOT14_ALT:
 176                         pr_err("%s: unexpected ALT relocation: %u\n",
 177                                mod->name,
 178                                ELF32_R_TYPE(rela[i].r_info));
 179                         return -ENOEXEC;
 180
 181                 default:
 182                         pr_err("%s: unexpected relocation: %u\n",
 183                                mod->name,
 184                                ELF32_R_TYPE(rela[i].r_info));
 185                         return -ENOEXEC;
 186                 }
 187         }
 188         return 0;
 189 }