root/arch/c6x/kernel/module.c

DEFINITIONS

1. fixup_pcr
2. apply_relocate_add

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Port on Texas Instruments TMS320C6x architecture
   4  *
   5  *  Copyright (C) 2005, 2009, 2010, 2011 Texas Instruments Incorporated
   6  *  Author: Thomas Charleux (thomas.charleux@jaluna.com)
   7  */
   8 #include <linux/moduleloader.h>
   9 #include <linux/elf.h>
  10 #include <linux/vmalloc.h>
  11 #include <linux/kernel.h>
  12 
  13 static inline int fixup_pcr(u32 *ip, Elf32_Addr dest, u32 maskbits, int shift)
  14 {
  15         u32 opcode;
  16         long ep = (long)ip & ~31;
  17         long delta = ((long)dest - ep) >> 2;
  18         long mask = (1 << maskbits) - 1;
  19 
  20         if ((delta >> (maskbits - 1)) == 0 ||
  21             (delta >> (maskbits - 1)) == -1) {
  22                 opcode = *ip;
  23                 opcode &= ~(mask << shift);
  24                 opcode |= ((delta & mask) << shift);
  25                 *ip = opcode;
  26 
  27                 pr_debug("REL PCR_S%d[%p] dest[%p] opcode[%08x]\n",
  28                          maskbits, ip, (void *)dest, opcode);
  29 
  30                 return 0;
  31         }
  32         pr_err("PCR_S%d reloc %p -> %p out of range!\n",
  33                maskbits, ip, (void *)dest);
  34 
  35         return -1;
  36 }
  37 
  38 /*
  39  * apply a RELA relocation
  40  */
  41 int apply_relocate_add(Elf32_Shdr *sechdrs,
  42                        const char *strtab,
  43                        unsigned int symindex,
  44                        unsigned int relsec,
  45                        struct module *me)
  46 {
  47         Elf32_Rela *rel = (void *) sechdrs[relsec].sh_addr;
  48         Elf_Sym *sym;
  49         u32 *location, opcode;
  50         unsigned int i;
  51         Elf32_Addr v;
  52         Elf_Addr offset = 0;
  53 
  54         pr_debug("Applying relocate section %u to %u with offset 0x%x\n",
  55                  relsec, sechdrs[relsec].sh_info, offset);
  56 
  57         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
  58                 /* This is where to make the change */
  59                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  60                         + rel[i].r_offset - offset;
  61 
  62                 /* This is the symbol it is referring to.  Note that all
  63                    undefined symbols have been resolved.  */
  64                 sym = (Elf_Sym *)sechdrs[symindex].sh_addr
  65                         + ELF32_R_SYM(rel[i].r_info);
  66 
  67                 /* this is the adjustment to be made */
  68                 v = sym->st_value + rel[i].r_addend;
  69 
  70                 switch (ELF32_R_TYPE(rel[i].r_info)) {
  71                 case R_C6000_ABS32:
  72                         pr_debug("RELA ABS32: [%p] = 0x%x\n", location, v);
  73                         *location = v;
  74                         break;
  75                 case R_C6000_ABS16:
  76                         pr_debug("RELA ABS16: [%p] = 0x%x\n", location, v);
  77                         *(u16 *)location = v;
  78                         break;
  79                 case R_C6000_ABS8:
  80                         pr_debug("RELA ABS8: [%p] = 0x%x\n", location, v);
  81                         *(u8 *)location = v;
  82                         break;
  83                 case R_C6000_ABS_L16:
  84                         opcode = *location;
  85                         opcode &= ~0x7fff80;
  86                         opcode |= ((v & 0xffff) << 7);
  87                         pr_debug("RELA ABS_L16[%p] v[0x%x] opcode[0x%x]\n",
  88                                  location, v, opcode);
  89                         *location = opcode;
  90                         break;
  91                 case R_C6000_ABS_H16:
  92                         opcode = *location;
  93                         opcode &= ~0x7fff80;
  94                         opcode |= ((v >> 9) & 0x7fff80);
  95                         pr_debug("RELA ABS_H16[%p] v[0x%x] opcode[0x%x]\n",
  96                                  location, v, opcode);
  97                         *location = opcode;
  98                         break;
  99                 case R_C6000_PCR_S21:
 100                         if (fixup_pcr(location, v, 21, 7))
 101                                 return -ENOEXEC;
 102                         break;
 103                 case R_C6000_PCR_S12:
 104                         if (fixup_pcr(location, v, 12, 16))
 105                                 return -ENOEXEC;
 106                         break;
 107                 case R_C6000_PCR_S10:
 108                         if (fixup_pcr(location, v, 10, 13))
 109                                 return -ENOEXEC;
 110                         break;
 111                 default:
 112                         pr_err("module %s: Unknown RELA relocation: %u\n",
 113                                me->name, ELF32_R_TYPE(rel[i].r_info));
 114                         return -ENOEXEC;
 115                 }
 116         }
 117 
 118         return 0;
 119 }