arch/nios2/kernel/module.c

   1 /*
   2  * Kernel module support for Nios II.
   3  *
   4  * Copyright (C) 2004 Microtronix Datacom Ltd.
   5  *   Written by Wentao Xu <xuwentao@microtronix.com>
   6  * Copyright (C) 2001, 2003 Rusty Russell
   7  *
   8  * This file is subject to the terms and conditions of the GNU General
   9  * Public License.  See the file COPYING in the main directory of this
  10  * archive for more details.
  11  */
  12
  13 #include <linux/moduleloader.h>
  14 #include <linux/elf.h>
  15 #include <linux/mm.h>
  16 #include <linux/slab.h>
  17 #include <linux/fs.h>
  18 #include <linux/string.h>
  19 #include <linux/kernel.h>
  20
  21 #include <asm/cacheflush.h>
  22
  23 int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
  24                         unsigned int symindex, unsigned int relsec,
  25                         struct module *mod)
  26 {
  27         unsigned int i;
  28         Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
  29
  30         pr_debug("Applying relocate section %u to %u\n", relsec,
  31                  sechdrs[relsec].sh_info);
  32
  33         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
  34                 /* This is where to make the change */
  35                 uint32_t word;
  36                 uint32_t *loc
  37                         = ((void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  38                            + rela[i].r_offset);
  39                 /* This is the symbol it is referring to.  Note that all
  40                    undefined symbols have been resolved.  */
  41                 Elf32_Sym *sym
  42                         = ((Elf32_Sym *)sechdrs[symindex].sh_addr
  43                                 + ELF32_R_SYM(rela[i].r_info));
  44                 uint32_t v = sym->st_value + rela[i].r_addend;
  45
  46                 pr_debug("reltype %d 0x%x name:<%s>\n",
  47                         ELF32_R_TYPE(rela[i].r_info),
  48                         rela[i].r_offset, strtab + sym->st_name);
  49
  50                 switch (ELF32_R_TYPE(rela[i].r_info)) {
  51                 case R_NIOS2_NONE:
  52                         break;
  53                 case R_NIOS2_BFD_RELOC_32:
  54                         *loc += v;
  55                         break;
  56                 case R_NIOS2_PCREL16:
  57                         v -= (uint32_t)loc + 4;
  58                         if ((int32_t)v > 0x7fff ||
  59                                 (int32_t)v < -(int32_t)0x8000) {
  60                                 pr_err("module %s: relocation overflow\n",
  61                                         mod->name);
  62                                 return -ENOEXEC;
  63                         }
  64                         word = *loc;
  65                         *loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |
  66                                 (word & 0x3f);
  67                         break;
  68                 case R_NIOS2_CALL26:
  69                         if (v & 3) {
  70                                 pr_err("module %s: dangerous relocation\n",
  71                                         mod->name);
  72                                 return -ENOEXEC;
  73                         }
  74                         if ((v >> 28) != ((uint32_t)loc >> 28)) {
  75                                 pr_err("module %s: relocation overflow\n",
  76                                         mod->name);
  77                                 return -ENOEXEC;
  78                         }
  79                         *loc = (*loc & 0x3f) | ((v >> 2) << 6);
  80                         break;
  81                 case R_NIOS2_HI16:
  82                         word = *loc;
  83                         *loc = ((((word >> 22) << 16) |
  84                                 ((v >> 16) & 0xffff)) << 6) | (word & 0x3f);
  85                         break;
  86                 case R_NIOS2_LO16:
  87                         word = *loc;
  88                         *loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |
  89                                         (word & 0x3f);
  90                         break;
  91                 case R_NIOS2_HIADJ16:
  92                         {
  93                                 Elf32_Addr word2;
  94
  95                                 word = *loc;
  96                                 word2 = ((v >> 16) + ((v >> 15) & 1)) & 0xffff;
  97                                 *loc = ((((word >> 22) << 16) | word2) << 6) |
  98                                                 (word & 0x3f);
  99                         }
 100                         break;
 101
 102                 default:
 103                         pr_err("module %s: Unknown reloc: %u\n",
 104                                 mod->name, ELF32_R_TYPE(rela[i].r_info));
 105                         return -ENOEXEC;
 106                 }
 107         }
 108
 109         return 0;
 110 }
 111
 112 int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
 113                         struct module *me)
 114 {
 115         flush_cache_all();
 116         return 0;
 117 }