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/pgtable.h>
  23 #include <asm/cacheflush.h>
  24
  25 /*
  26  * Modules should NOT be allocated with kmalloc for (obvious) reasons.
  27  * But we do it for now to avoid relocation issues. CALL26/PCREL26 cannot reach
  28  * from 0x80000000 (vmalloc area) to 0xc00000000 (kernel) (kmalloc returns
  29  * addresses in 0xc0000000)
  30  */
  31 void *module_alloc(unsigned long size)
  32 {
  33         if (size == 0)
  34                 return NULL;
  35         return kmalloc(size, GFP_KERNEL);
  36 }
  37
  38 /* Free memory returned from module_alloc */
  39 void module_memfree(void *module_region)
  40 {
  41         kfree(module_region);
  42 }
  43
  44 int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
  45                         unsigned int symindex, unsigned int relsec,
  46                         struct module *mod)
  47 {
  48         unsigned int i;
  49         Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
  50
  51         pr_debug("Applying relocate section %u to %u\n", relsec,
  52                  sechdrs[relsec].sh_info);
  53
  54         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
  55                 /* This is where to make the change */
  56                 uint32_t word;
  57                 uint32_t *loc
  58                         = ((void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  59                            + rela[i].r_offset);
  60                 /* This is the symbol it is referring to.  Note that all
  61                    undefined symbols have been resolved.  */
  62                 Elf32_Sym *sym
  63                         = ((Elf32_Sym *)sechdrs[symindex].sh_addr
  64                                 + ELF32_R_SYM(rela[i].r_info));
  65                 uint32_t v = sym->st_value + rela[i].r_addend;
  66
  67                 pr_debug("reltype %d 0x%x name:<%s>\n",
  68                         ELF32_R_TYPE(rela[i].r_info),
  69                         rela[i].r_offset, strtab + sym->st_name);
  70
  71                 switch (ELF32_R_TYPE(rela[i].r_info)) {
  72                 case R_NIOS2_NONE:
  73                         break;
  74                 case R_NIOS2_BFD_RELOC_32:
  75                         *loc += v;
  76                         break;
  77                 case R_NIOS2_PCREL16:
  78                         v -= (uint32_t)loc + 4;
  79                         if ((int32_t)v > 0x7fff ||
  80                                 (int32_t)v < -(int32_t)0x8000) {
  81                                 pr_err("module %s: relocation overflow\n",
  82                                         mod->name);
  83                                 return -ENOEXEC;
  84                         }
  85                         word = *loc;
  86                         *loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |
  87                                 (word & 0x3f);
  88                         break;
  89                 case R_NIOS2_CALL26:
  90                         if (v & 3) {
  91                                 pr_err("module %s: dangerous relocation\n",
  92                                         mod->name);
  93                                 return -ENOEXEC;
  94                         }
  95                         if ((v >> 28) != ((uint32_t)loc >> 28)) {
  96                                 pr_err("module %s: relocation overflow\n",
  97                                         mod->name);
  98                                 return -ENOEXEC;
  99                         }
 100                         *loc = (*loc & 0x3f) | ((v >> 2) << 6);
 101                         break;
 102                 case R_NIOS2_HI16:
 103                         word = *loc;
 104                         *loc = ((((word >> 22) << 16) |
 105                                 ((v >> 16) & 0xffff)) << 6) | (word & 0x3f);
 106                         break;
 107                 case R_NIOS2_LO16:
 108                         word = *loc;
 109                         *loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |
 110                                         (word & 0x3f);
 111                         break;
 112                 case R_NIOS2_HIADJ16:
 113                         {
 114                                 Elf32_Addr word2;
 115
 116                                 word = *loc;
 117                                 word2 = ((v >> 16) + ((v >> 15) & 1)) & 0xffff;
 118                                 *loc = ((((word >> 22) << 16) | word2) << 6) |
 119                                                 (word & 0x3f);
 120                         }
 121                         break;
 122
 123                 default:
 124                         pr_err("module %s: Unknown reloc: %u\n",
 125                                 mod->name, ELF32_R_TYPE(rela[i].r_info));
 126                         return -ENOEXEC;
 127                 }
 128         }
 129
 130         return 0;
 131 }
 132
 133 int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
 134                         struct module *me)
 135 {
 136         flush_cache_all();
 137         return 0;
 138 }