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 #undef DEBUG_RELOCATE
  26
  27 static int
  28 decode_calln_opcode (unsigned char *location)
  29 {
  30 #ifdef __XTENSA_EB__
  31         return (location[0] & 0xf0) == 0x50;
  32 #endif
  33 #ifdef __XTENSA_EL__
  34         return (location[0] & 0xf) == 0x5;
  35 #endif
  36 }
  37
  38 static int
  39 decode_l32r_opcode (unsigned char *location)
  40 {
  41 #ifdef __XTENSA_EB__
  42         return (location[0] & 0xf0) == 0x10;
  43 #endif
  44 #ifdef __XTENSA_EL__
  45         return (location[0] & 0xf) == 0x1;
  46 #endif
  47 }
  48
  49 int apply_relocate_add(Elf32_Shdr *sechdrs,
  50                        const char *strtab,
  51                        unsigned int symindex,
  52                        unsigned int relsec,
  53                        struct module *mod)
  54 {
  55         unsigned int i;
  56         Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
  57         Elf32_Sym *sym;
  58         unsigned char *location;
  59         uint32_t value;
  60
  61 #ifdef DEBUG_RELOCATE
  62         printk("Applying relocate section %u to %u\n", relsec,
  63                sechdrs[relsec].sh_info);
  64 #endif
  65         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
  66                 location = (char *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  67                         + rela[i].r_offset;
  68                 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
  69                         + ELF32_R_SYM(rela[i].r_info);
  70                 value = sym->st_value + rela[i].r_addend;
  71
  72                 switch (ELF32_R_TYPE(rela[i].r_info)) {
  73                 case R_XTENSA_NONE:
  74                 case R_XTENSA_DIFF8:
  75                 case R_XTENSA_DIFF16:
  76                 case R_XTENSA_DIFF32:
  77                 case R_XTENSA_ASM_EXPAND:
  78                         break;
  79
  80                 case R_XTENSA_32:
  81                 case R_XTENSA_PLT:
  82                         *(uint32_t *)location += value;
  83                         break;
  84
  85                 case R_XTENSA_SLOT0_OP:
  86                         if (decode_calln_opcode(location)) {
  87                                 value -= ((unsigned long)location & -4) + 4;
  88                                 if ((value & 3) != 0 ||
  89                                     ((value + (1 << 19)) >> 20) != 0) {
  90                                         printk("%s: relocation out of range, "
  91                                                "section %d reloc %d "
  92                                                "sym '%s'\n",
  93                                                mod->name, relsec, i,
  94                                                strtab + sym->st_name);
  95                                         return -ENOEXEC;
  96                                 }
  97                                 value = (signed int)value >> 2;
  98 #ifdef __XTENSA_EB__
  99                                 location[0] = ((location[0] & ~0x3) |
 100                                             ((value >> 16) & 0x3));
 101                                 location[1] = (value >> 8) & 0xff;
 102                                 location[2] = value & 0xff;
 103 #endif
 104 #ifdef __XTENSA_EL__
 105                                 location[0] = ((location[0] & ~0xc0) |
 106                                             ((value << 6) & 0xc0));
 107                                 location[1] = (value >> 2) & 0xff;
 108                                 location[2] = (value >> 10) & 0xff;
 109 #endif
 110                         } else if (decode_l32r_opcode(location)) {
 111                                 value -= (((unsigned long)location + 3) & -4);
 112                                 if ((value & 3) != 0 ||
 113                                     (signed int)value >> 18 != -1) {
 114                                         printk("%s: relocation out of range, "
 115                                                "section %d reloc %d "
 116                                                "sym '%s'\n",
 117                                                mod->name, relsec, i,
 118                                                strtab + sym->st_name);
 119                                         return -ENOEXEC;
 120                                 }
 121                                 value = (signed int)value >> 2;
 122
 123 #ifdef __XTENSA_EB__
 124                                 location[1] = (value >> 8) & 0xff;
 125                                 location[2] = value & 0xff;
 126 #endif
 127 #ifdef __XTENSA_EL__
 128                                 location[1] = value & 0xff;
 129                                 location[2] = (value >> 8) & 0xff;
 130 #endif
 131                         }
 132                         /* FIXME: Ignore any other opcodes.  The Xtensa
 133                            assembler currently assumes that the linker will
 134                            always do relaxation and so all PC-relative
 135                            operands need relocations.  (The assembler also
 136                            writes out the tentative PC-relative values,
 137                            assuming no link-time relaxation, so it is usually
 138                            safe to ignore the relocations.)  If the
 139                            assembler's "--no-link-relax" flag can be made to
 140                            work, and if all kernel modules can be assembled
 141                            with that flag, then unexpected relocations could
 142                            be detected here.  */
 143                         break;
 144
 145                 case R_XTENSA_SLOT1_OP:
 146                 case R_XTENSA_SLOT2_OP:
 147                 case R_XTENSA_SLOT3_OP:
 148                 case R_XTENSA_SLOT4_OP:
 149                 case R_XTENSA_SLOT5_OP:
 150                 case R_XTENSA_SLOT6_OP:
 151                 case R_XTENSA_SLOT7_OP:
 152                 case R_XTENSA_SLOT8_OP:
 153                 case R_XTENSA_SLOT9_OP:
 154                 case R_XTENSA_SLOT10_OP:
 155                 case R_XTENSA_SLOT11_OP:
 156                 case R_XTENSA_SLOT12_OP:
 157                 case R_XTENSA_SLOT13_OP:
 158                 case R_XTENSA_SLOT14_OP:
 159                         printk("%s: unexpected FLIX relocation: %u\n",
 160                                mod->name,
 161                                ELF32_R_TYPE(rela[i].r_info));
 162                         return -ENOEXEC;
 163
 164                 case R_XTENSA_SLOT0_ALT:
 165                 case R_XTENSA_SLOT1_ALT:
 166                 case R_XTENSA_SLOT2_ALT:
 167                 case R_XTENSA_SLOT3_ALT:
 168                 case R_XTENSA_SLOT4_ALT:
 169                 case R_XTENSA_SLOT5_ALT:
 170                 case R_XTENSA_SLOT6_ALT:
 171                 case R_XTENSA_SLOT7_ALT:
 172                 case R_XTENSA_SLOT8_ALT:
 173                 case R_XTENSA_SLOT9_ALT:
 174                 case R_XTENSA_SLOT10_ALT:
 175                 case R_XTENSA_SLOT11_ALT:
 176                 case R_XTENSA_SLOT12_ALT:
 177                 case R_XTENSA_SLOT13_ALT:
 178                 case R_XTENSA_SLOT14_ALT:
 179                         printk("%s: unexpected ALT relocation: %u\n",
 180                                mod->name,
 181                                ELF32_R_TYPE(rela[i].r_info));
 182                         return -ENOEXEC;
 183
 184                 default:
 185                         printk("%s: unexpected relocation: %u\n",
 186                                mod->name,
 187                                ELF32_R_TYPE(rela[i].r_info));
 188                         return -ENOEXEC;
 189                 }
 190         }
 191         return 0;
 192 }