arch/sh/kernel/module.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*  Kernel module help for SH.
   3
   4     SHcompact version by Kaz Kojima and Paul Mundt.
   5
   6     SHmedia bits:
   7
   8         Copyright 2004 SuperH (UK) Ltd
   9         Author: Richard Curnow
  10
  11         Based on the sh version, and on code from the sh64-specific parts of
  12         modutils, originally written by Richard Curnow and Ben Gaster.
  13 */
  14 #include <linux/moduleloader.h>
  15 #include <linux/elf.h>
  16 #include <linux/vmalloc.h>
  17 #include <linux/bug.h>
  18 #include <linux/fs.h>
  19 #include <linux/string.h>
  20 #include <linux/kernel.h>
  21 #include <asm/unaligned.h>
  22 #include <asm/dwarf.h>
  23
  24 int apply_relocate_add(Elf32_Shdr *sechdrs,
  25                    const char *strtab,
  26                    unsigned int symindex,
  27                    unsigned int relsec,
  28                    struct module *me)
  29 {
  30         unsigned int i;
  31         Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
  32         Elf32_Sym *sym;
  33         Elf32_Addr relocation;
  34         uint32_t *location;
  35         uint32_t value;
  36
  37         pr_debug("Applying relocate section %u to %u\n", relsec,
  38                  sechdrs[relsec].sh_info);
  39         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
  40                 /* This is where to make the change */
  41                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  42                         + rel[i].r_offset;
  43                 /* This is the symbol it is referring to.  Note that all
  44                    undefined symbols have been resolved.  */
  45                 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
  46                         + ELF32_R_SYM(rel[i].r_info);
  47                 relocation = sym->st_value + rel[i].r_addend;
  48
  49 #ifdef CONFIG_SUPERH64
  50                 /* For text addresses, bit2 of the st_other field indicates
  51                  * whether the symbol is SHmedia (1) or SHcompact (0).  If
  52                  * SHmedia, the LSB of the symbol needs to be asserted
  53                  * for the CPU to be in SHmedia mode when it starts executing
  54                  * the branch target. */
  55                 relocation |= !!(sym->st_other & 4);
  56 #endif
  57
  58                 switch (ELF32_R_TYPE(rel[i].r_info)) {
  59                 case R_SH_NONE:
  60                         break;
  61                 case R_SH_DIR32:
  62                         value = get_unaligned(location);
  63                         value += relocation;
  64                         put_unaligned(value, location);
  65                         break;
  66                 case R_SH_REL32:
  67                         relocation = (relocation - (Elf32_Addr) location);
  68                         value = get_unaligned(location);
  69                         value += relocation;
  70                         put_unaligned(value, location);
  71                         break;
  72                 case R_SH_IMM_LOW16:
  73                         *location = (*location & ~0x3fffc00) |
  74                                 ((relocation & 0xffff) << 10);
  75                         break;
  76                 case R_SH_IMM_MEDLOW16:
  77                         *location = (*location & ~0x3fffc00) |
  78                                 (((relocation >> 16) & 0xffff) << 10);
  79                         break;
  80                 case R_SH_IMM_LOW16_PCREL:
  81                         relocation -= (Elf32_Addr) location;
  82                         *location = (*location & ~0x3fffc00) |
  83                                 ((relocation & 0xffff) << 10);
  84                         break;
  85                 case R_SH_IMM_MEDLOW16_PCREL:
  86                         relocation -= (Elf32_Addr) location;
  87                         *location = (*location & ~0x3fffc00) |
  88                                 (((relocation >> 16) & 0xffff) << 10);
  89                         break;
  90                 default:
  91                         printk(KERN_ERR "module %s: Unknown relocation: %u\n",
  92                                me->name, ELF32_R_TYPE(rel[i].r_info));
  93                         return -ENOEXEC;
  94                 }
  95         }
  96         return 0;
  97 }
  98
  99 int module_finalize(const Elf_Ehdr *hdr,
 100                     const Elf_Shdr *sechdrs,
 101                     struct module *me)
 102 {
 103         int ret = 0;
 104
 105         ret |= module_dwarf_finalize(hdr, sechdrs, me);
 106
 107         return ret;
 108 }
 109
 110 void module_arch_cleanup(struct module *mod)
 111 {
 112         module_dwarf_cleanup(mod);
 113 }