LXR linux/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
  17static 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 */
  45int 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}
 124