arch/c6x/kernel/module.c

   1 /*
   2  *  Port on Texas Instruments TMS320C6x architecture
   3  *
   4  *  Copyright (C) 2005, 2009, 2010, 2011 Texas Instruments Incorporated
   5  *  Author: Thomas Charleux (thomas.charleux@jaluna.com)
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2 as
   9  *  published by the Free Software Foundation.
  10  *
  11  */
  12 #include <linux/moduleloader.h>
  13 #include <linux/elf.h>
  14 #include <linux/vmalloc.h>
  15 #include <linux/kernel.h>
  16
  17 static inline int fixup_pcr(u32 *ip, Elf32_Addr dest, u32 maskbits, int shift)
  18 {
  19         u32 opcode;
  20         long ep = (long)ip & ~31;
  21         long delta = ((long)dest - ep) >> 2;
  22         long mask = (1 << maskbits) - 1;
  23
  24         if ((delta >> (maskbits - 1)) == 0 ||
  25             (delta >> (maskbits - 1)) == -1) {
  26                 opcode = *ip;
  27                 opcode &= ~(mask << shift);
  28                 opcode |= ((delta & mask) << shift);
  29                 *ip = opcode;
  30
  31                 pr_debug("REL PCR_S%d[%p] dest[%p] opcode[%08x]\n",
  32                          maskbits, ip, (void *)dest, opcode);
  33
  34                 return 0;
  35         }
  36         pr_err("PCR_S%d reloc %p -> %p out of range!\n",
  37                maskbits, ip, (void *)dest);
  38
  39         return -1;
  40 }
  41
  42 /*
  43  * apply a RELA relocation
  44  */
  45 int apply_relocate_add(Elf32_Shdr *sechdrs,
  46                        const char *strtab,
  47                        unsigned int symindex,
  48                        unsigned int relsec,
  49                        struct module *me)
  50 {
  51         Elf32_Rela *rel = (void *) sechdrs[relsec].sh_addr;
  52         Elf_Sym *sym;
  53         u32 *location, opcode;
  54         unsigned int i;
  55         Elf32_Addr v;
  56         Elf_Addr offset = 0;
  57
  58         pr_debug("Applying relocate section %u to %u with offset 0x%x\n",
  59                  relsec, sechdrs[relsec].sh_info, offset);
  60
  61         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
  62                 /* This is where to make the change */
  63                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  64                         + rel[i].r_offset - offset;
  65
  66                 /* This is the symbol it is referring to.  Note that all
  67                    undefined symbols have been resolved.  */
  68                 sym = (Elf_Sym *)sechdrs[symindex].sh_addr
  69                         + ELF32_R_SYM(rel[i].r_info);
  70
  71                 /* this is the adjustment to be made */
  72                 v = sym->st_value + rel[i].r_addend;
  73
  74                 switch (ELF32_R_TYPE(rel[i].r_info)) {
  75                 case R_C6000_ABS32:
  76                         pr_debug("RELA ABS32: [%p] = 0x%x\n", location, v);
  77                         *location = v;
  78                         break;
  79                 case R_C6000_ABS16:
  80                         pr_debug("RELA ABS16: [%p] = 0x%x\n", location, v);
  81                         *(u16 *)location = v;
  82                         break;
  83                 case R_C6000_ABS8:
  84                         pr_debug("RELA ABS8: [%p] = 0x%x\n", location, v);
  85                         *(u8 *)location = v;
  86                         break;
  87                 case R_C6000_ABS_L16:
  88                         opcode = *location;
  89                         opcode &= ~0x7fff80;
  90                         opcode |= ((v & 0xffff) << 7);
  91                         pr_debug("RELA ABS_L16[%p] v[0x%x] opcode[0x%x]\n",
  92                                  location, v, opcode);
  93                         *location = opcode;
  94                         break;
  95                 case R_C6000_ABS_H16:
  96                         opcode = *location;
  97                         opcode &= ~0x7fff80;
  98                         opcode |= ((v >> 9) & 0x7fff80);
  99                         pr_debug("RELA ABS_H16[%p] v[0x%x] opcode[0x%x]\n",
 100                                  location, v, opcode);
 101                         *location = opcode;
 102                         break;
 103                 case R_C6000_PCR_S21:
 104                         if (fixup_pcr(location, v, 21, 7))
 105                                 return -ENOEXEC;
 106                         break;
 107                 case R_C6000_PCR_S12:
 108                         if (fixup_pcr(location, v, 12, 16))
 109                                 return -ENOEXEC;
 110                         break;
 111                 case R_C6000_PCR_S10:
 112                         if (fixup_pcr(location, v, 10, 13))
 113                                 return -ENOEXEC;
 114                         break;
 115                 default:
 116                         pr_err("module %s: Unknown RELA relocation: %u\n",
 117                                me->name, ELF32_R_TYPE(rel[i].r_info));
 118                         return -ENOEXEC;
 119                 }
 120         }
 121
 122         return 0;
 123 }