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/vmalloc.h>
  17 #include <linux/slab.h>
  18 #include <linux/fs.h>
  19 #include <linux/string.h>
  20 #include <linux/kernel.h>
  21
  22 #include <asm/cacheflush.h>
  23
  24 /*
  25  * Modules should NOT be allocated with kmalloc for (obvious) reasons.
  26  * But we do it for now to avoid relocation issues. CALL26/PCREL26 cannot reach
  27  * from 0x80000000 (vmalloc area) to 0xc00000000 (kernel) (kmalloc returns
  28  * addresses in 0xc0000000)
  29  */
  30 void *module_alloc(unsigned long size)
  31 {
  32         if (size == 0)
  33                 return NULL;
  34         return kmalloc(size, GFP_KERNEL);
  35 }
  36
  37 /* Free memory returned from module_alloc */
  38 void module_memfree(void *module_region)
  39 {
  40         kfree(module_region);
  41 }
  42
  43 int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
  44                         unsigned int symindex, unsigned int relsec,
  45                         struct module *mod)
  46 {
  47         unsigned int i;
  48         Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
  49
  50         pr_debug("Applying relocate section %u to %u\n", relsec,
  51                  sechdrs[relsec].sh_info);
  52
  53         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
  54                 /* This is where to make the change */
  55                 uint32_t word;
  56                 uint32_t *loc
  57                         = ((void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  58                            + rela[i].r_offset);
  59                 /* This is the symbol it is referring to.  Note that all
  60                    undefined symbols have been resolved.  */
  61                 Elf32_Sym *sym
  62                         = ((Elf32_Sym *)sechdrs[symindex].sh_addr
  63                                 + ELF32_R_SYM(rela[i].r_info));
  64                 uint32_t v = sym->st_value + rela[i].r_addend;
  65
  66                 pr_debug("reltype %d 0x%x name:<%s>\n",
  67                         ELF32_R_TYPE(rela[i].r_info),
  68                         rela[i].r_offset, strtab + sym->st_name);
  69
  70                 switch (ELF32_R_TYPE(rela[i].r_info)) {
  71                 case R_NIOS2_NONE:
  72                         break;
  73                 case R_NIOS2_BFD_RELOC_32:
  74                         *loc += v;
  75                         break;
  76                 case R_NIOS2_PCREL16:
  77                         v -= (uint32_t)loc + 4;
  78                         if ((int32_t)v > 0x7fff ||
  79                                 (int32_t)v < -(int32_t)0x8000) {
  80                                 pr_err("module %s: relocation overflow\n",
  81                                         mod->name);
  82                                 return -ENOEXEC;
  83                         }
  84                         word = *loc;
  85                         *loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |
  86                                 (word & 0x3f);
  87                         break;
  88                 case R_NIOS2_CALL26:
  89                         if (v & 3) {
  90                                 pr_err("module %s: dangerous relocation\n",
  91                                         mod->name);
  92                                 return -ENOEXEC;
  93                         }
  94                         if ((v >> 28) != ((uint32_t)loc >> 28)) {
  95                                 pr_err("module %s: relocation overflow\n",
  96                                         mod->name);
  97                                 return -ENOEXEC;
  98                         }
  99                         *loc = (*loc & 0x3f) | ((v >> 2) << 6);
 100                         break;
 101                 case R_NIOS2_HI16:
 102                         word = *loc;
 103                         *loc = ((((word >> 22) << 16) |
 104                                 ((v >> 16) & 0xffff)) << 6) | (word & 0x3f);
 105                         break;
 106                 case R_NIOS2_LO16:
 107                         word = *loc;
 108                         *loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |
 109                                         (word & 0x3f);
 110                         break;
 111                 case R_NIOS2_HIADJ16:
 112                         {
 113                                 Elf32_Addr word2;
 114
 115                                 word = *loc;
 116                                 word2 = ((v >> 16) + ((v >> 15) & 1)) & 0xffff;
 117                                 *loc = ((((word >> 22) << 16) | word2) << 6) |
 118                                                 (word & 0x3f);
 119                         }
 120                         break;
 121
 122                 default:
 123                         pr_err("module %s: Unknown reloc: %u\n",
 124                                 mod->name, ELF32_R_TYPE(rela[i].r_info));
 125                         return -ENOEXEC;
 126                 }
 127         }
 128
 129         return 0;
 130 }
 131
 132 int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
 133                         struct module *me)
 134 {
 135         flush_cache_all();
 136         return 0;
 137 }