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   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 void *module_alloc(unsigned long size)
  28 {
  29         if (size == 0)
  30                 return NULL;
  31         return vmalloc_exec(size);
  32 }
  33
  34 void module_free(struct module *mod, void *module_region)
  35 {
  36         vfree(module_region);
  37         /* FIXME: If module_region == mod->init_region, trim exception
  38            table entries. */
  39 }
  40
  41 int module_frob_arch_sections(Elf32_Ehdr *hdr,
  42                               Elf32_Shdr *sechdrs,
  43                               char *secstrings,
  44                               struct module *mod)
  45 {
  46         return 0;
  47 }
  48
  49 static int
  50 decode_calln_opcode (unsigned char *location)
  51 {
  52 #ifdef __XTENSA_EB__
  53         return (location[0] & 0xf0) == 0x50;
  54 #endif
  55 #ifdef __XTENSA_EL__
  56         return (location[0] & 0xf) == 0x5;
  57 #endif
  58 }
  59
  60 static int
  61 decode_l32r_opcode (unsigned char *location)
  62 {
  63 #ifdef __XTENSA_EB__
  64         return (location[0] & 0xf0) == 0x10;
  65 #endif
  66 #ifdef __XTENSA_EL__
  67         return (location[0] & 0xf) == 0x1;
  68 #endif
  69 }
  70
  71 int apply_relocate(Elf32_Shdr *sechdrs,
  72                    const char *strtab,
  73                    unsigned int symindex,
  74                    unsigned int relsec,
  75                    struct module *mod)
  76 {
  77         printk(KERN_ERR "module %s: REL RELOCATION unsupported\n",
  78                mod->name);
  79         return -ENOEXEC;
  80
  81 }
  82
  83 int apply_relocate_add(Elf32_Shdr *sechdrs,
  84                        const char *strtab,
  85                        unsigned int symindex,
  86                        unsigned int relsec,
  87                        struct module *mod)
  88 {
  89         unsigned int i;
  90         Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
  91         Elf32_Sym *sym;
  92         unsigned char *location;
  93         uint32_t value;
  94
  95 #ifdef DEBUG_RELOCATE
  96         printk("Applying relocate section %u to %u\n", relsec,
  97                sechdrs[relsec].sh_info);
  98 #endif
  99         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
 100                 location = (char *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 101                         + rela[i].r_offset;
 102                 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
 103                         + ELF32_R_SYM(rela[i].r_info);
 104                 value = sym->st_value + rela[i].r_addend;
 105
 106                 switch (ELF32_R_TYPE(rela[i].r_info)) {
 107                 case R_XTENSA_NONE:
 108                 case R_XTENSA_DIFF8:
 109                 case R_XTENSA_DIFF16:
 110                 case R_XTENSA_DIFF32:
 111                 case R_XTENSA_ASM_EXPAND:
 112                         break;
 113
 114                 case R_XTENSA_32:
 115                 case R_XTENSA_PLT:
 116                         *(uint32_t *)location += value;
 117                         break;
 118
 119                 case R_XTENSA_SLOT0_OP:
 120                         if (decode_calln_opcode(location)) {
 121                                 value -= ((unsigned long)location & -4) + 4;
 122                                 if ((value & 3) != 0 ||
 123                                     ((value + (1 << 19)) >> 20) != 0) {
 124                                         printk("%s: relocation out of range, "
 125                                                "section %d reloc %d "
 126                                                "sym '%s'\n",
 127                                                mod->name, relsec, i,
 128                                                strtab + sym->st_name);
 129                                         return -ENOEXEC;
 130                                 }
 131                                 value = (signed int)value >> 2;
 132 #ifdef __XTENSA_EB__
 133                                 location[0] = ((location[0] & ~0x3) |
 134                                             ((value >> 16) & 0x3));
 135                                 location[1] = (value >> 8) & 0xff;
 136                                 location[2] = value & 0xff;
 137 #endif
 138 #ifdef __XTENSA_EL__
 139                                 location[0] = ((location[0] & ~0xc0) |
 140                                             ((value << 6) & 0xc0));
 141                                 location[1] = (value >> 2) & 0xff;
 142                                 location[2] = (value >> 10) & 0xff;
 143 #endif
 144                         } else if (decode_l32r_opcode(location)) {
 145                                 value -= (((unsigned long)location + 3) & -4);
 146                                 if ((value & 3) != 0 ||
 147                                     (signed int)value >> 18 != -1) {
 148                                         printk("%s: relocation out of range, "
 149                                                "section %d reloc %d "
 150                                                "sym '%s'\n",
 151                                                mod->name, relsec, i,
 152                                                strtab + sym->st_name);
 153                                         return -ENOEXEC;
 154                                 }
 155                                 value = (signed int)value >> 2;
 156
 157 #ifdef __XTENSA_EB__
 158                                 location[1] = (value >> 8) & 0xff;
 159                                 location[2] = value & 0xff;
 160 #endif
 161 #ifdef __XTENSA_EL__
 162                                 location[1] = value & 0xff;
 163                                 location[2] = (value >> 8) & 0xff;
 164 #endif
 165                         }
 166                         /* FIXME: Ignore any other opcodes.  The Xtensa
 167                            assembler currently assumes that the linker will
 168                            always do relaxation and so all PC-relative
 169                            operands need relocations.  (The assembler also
 170                            writes out the tentative PC-relative values,
 171                            assuming no link-time relaxation, so it is usually
 172                            safe to ignore the relocations.)  If the
 173                            assembler's "--no-link-relax" flag can be made to
 174                            work, and if all kernel modules can be assembled
 175                            with that flag, then unexpected relocations could
 176                            be detected here.  */
 177                         break;
 178
 179                 case R_XTENSA_SLOT1_OP:
 180                 case R_XTENSA_SLOT2_OP:
 181                 case R_XTENSA_SLOT3_OP:
 182                 case R_XTENSA_SLOT4_OP:
 183                 case R_XTENSA_SLOT5_OP:
 184                 case R_XTENSA_SLOT6_OP:
 185                 case R_XTENSA_SLOT7_OP:
 186                 case R_XTENSA_SLOT8_OP:
 187                 case R_XTENSA_SLOT9_OP:
 188                 case R_XTENSA_SLOT10_OP:
 189                 case R_XTENSA_SLOT11_OP:
 190                 case R_XTENSA_SLOT12_OP:
 191                 case R_XTENSA_SLOT13_OP:
 192                 case R_XTENSA_SLOT14_OP:
 193                         printk("%s: unexpected FLIX relocation: %u\n",
 194                                mod->name,
 195                                ELF32_R_TYPE(rela[i].r_info));
 196                         return -ENOEXEC;
 197
 198                 case R_XTENSA_SLOT0_ALT:
 199                 case R_XTENSA_SLOT1_ALT:
 200                 case R_XTENSA_SLOT2_ALT:
 201                 case R_XTENSA_SLOT3_ALT:
 202                 case R_XTENSA_SLOT4_ALT:
 203                 case R_XTENSA_SLOT5_ALT:
 204                 case R_XTENSA_SLOT6_ALT:
 205                 case R_XTENSA_SLOT7_ALT:
 206                 case R_XTENSA_SLOT8_ALT:
 207                 case R_XTENSA_SLOT9_ALT:
 208                 case R_XTENSA_SLOT10_ALT:
 209                 case R_XTENSA_SLOT11_ALT:
 210                 case R_XTENSA_SLOT12_ALT:
 211                 case R_XTENSA_SLOT13_ALT:
 212                 case R_XTENSA_SLOT14_ALT:
 213                         printk("%s: unexpected ALT relocation: %u\n",
 214                                mod->name,
 215                                ELF32_R_TYPE(rela[i].r_info));
 216                         return -ENOEXEC;
 217
 218                 default:
 219                         printk("%s: unexpected relocation: %u\n",
 220                                mod->name,
 221                                ELF32_R_TYPE(rela[i].r_info));
 222                         return -ENOEXEC;
 223                 }
 224         }
 225         return 0;
 226 }
 227
 228 int module_finalize(const Elf_Ehdr *hdr,
 229                     const Elf_Shdr *sechdrs,
 230                     struct module *mod)
 231 {
 232         return 0;
 233 }
 234
 235 void module_arch_cleanup(struct module *mod)
 236 {
 237 }