arch/all-pc/boot/grub2-aros/grub-core/kern/arm64/dl.c

   1 /* dl.c - arch-dependent part of loadable module support */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2013  Free Software Foundation, Inc.
   5  *
   6  *  GRUB is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  GRUB is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <grub/dl.h>
  21 #include <grub/elf.h>
  22 #include <grub/misc.h>
  23 #include <grub/err.h>
  24 #include <grub/mm.h>
  25 #include <grub/i18n.h>
  26 #include <grub/cpu/reloc.h>
  27
  28 struct trampoline
  29 {
  30 #define LDR 0x58000050
  31 #define BR 0xd61f0200
  32   grub_uint32_t ldr; /* ldr     x16, 8 */
  33   grub_uint32_t br; /* br x16 */
  34   grub_uint64_t addr;
  35 };
  36
  37 /*
  38  * Check if EHDR is a valid ELF header.
  39  */
  40 grub_err_t
  41 grub_arch_dl_check_header (void *ehdr)
  42 {
  43   Elf_Ehdr *e = ehdr;
  44
  45   /* Check the magic numbers.  */
  46   if (e->e_ident[EI_CLASS] != ELFCLASS64
  47       || e->e_ident[EI_DATA] != ELFDATA2LSB || e->e_machine != EM_AARCH64)
  48     return grub_error (GRUB_ERR_BAD_OS,
  49                        N_("invalid arch-dependent ELF magic"));
  50
  51   return GRUB_ERR_NONE;
  52 }
  53
  54 #pragma GCC diagnostic ignored "-Wcast-align"
  55
  56 grub_err_t
  57 grub_arch_dl_get_tramp_got_size (const void *ehdr, grub_size_t *tramp,
  58                                  grub_size_t *got)
  59 {
  60   const Elf_Ehdr *e = ehdr;
  61   const Elf_Shdr *s;
  62   unsigned i;
  63
  64   *tramp = 0;
  65   *got = 0;
  66
  67   for (i = 0, s = (const Elf_Shdr *) ((grub_addr_t) e + e->e_shoff);
  68        i < e->e_shnum;
  69        i++, s = (const Elf_Shdr *) ((grub_addr_t) s + e->e_shentsize))
  70     if (s->sh_type == SHT_REL || s->sh_type == SHT_RELA)
  71       {
  72         const Elf_Rel *rel, *max;
  73
  74         for (rel = (const Elf_Rel *) ((grub_addr_t) e + s->sh_offset),
  75                max = rel + s->sh_size / s->sh_entsize;
  76              rel < max;
  77              rel = (const Elf_Rel *) ((grub_addr_t) rel + s->sh_entsize))
  78           switch (ELF_R_TYPE (rel->r_info))
  79             {
  80             case R_AARCH64_CALL26:
  81             case R_AARCH64_JUMP26:
  82               {
  83                 *tramp += sizeof (struct trampoline);
  84                 break;
  85               }
  86             }
  87       }
  88
  89   return GRUB_ERR_NONE;
  90 }
  91
  92 /*
  93  * Unified function for both REL and RELA
  94  */
  95 grub_err_t
  96 grub_arch_dl_relocate_symbols (grub_dl_t mod, void *ehdr,
  97                                Elf_Shdr *s, grub_dl_segment_t seg)
  98 {
  99   Elf_Rel *rel, *max;
 100
 101   for (rel = (Elf_Rel *) ((char *) ehdr + s->sh_offset),
 102          max = (Elf_Rel *) ((char *) rel + s->sh_size);
 103        rel < max;
 104        rel = (Elf_Rel *) ((char *) rel + s->sh_entsize))
 105     {
 106       Elf_Sym *sym;
 107       void *place;
 108       grub_uint64_t sym_addr;
 109
 110       if (rel->r_offset >= seg->size)
 111         return grub_error (GRUB_ERR_BAD_MODULE,
 112                            "reloc offset is out of the segment");
 113
 114       sym = (Elf_Sym *) ((char *) mod->symtab
 115                          + mod->symsize * ELF_R_SYM (rel->r_info));
 116
 117       sym_addr = sym->st_value;
 118       if (s->sh_type == SHT_RELA)
 119         sym_addr += ((Elf_Rela *) rel)->r_addend;
 120
 121       place = (void *) ((grub_addr_t) seg->addr + rel->r_offset);
 122
 123       switch (ELF_R_TYPE (rel->r_info))
 124         {
 125         case R_AARCH64_ABS64:
 126           {
 127             grub_uint64_t *abs_place = place;
 128
 129             grub_dprintf ("dl", "  reloc_abs64 %p => 0x%016llx\n",
 130                           place, (unsigned long long) sym_addr);
 131
 132             *abs_place = (grub_uint64_t) sym_addr;
 133           }
 134           break;
 135         case R_AARCH64_CALL26:
 136         case R_AARCH64_JUMP26:
 137           {
 138             grub_int64_t offset = sym_addr - (grub_uint64_t) place;
 139
 140             if (!grub_arm_64_check_xxxx26_offset (offset))
 141               {
 142                 struct trampoline *tp = mod->trampptr;
 143                 mod->trampptr = tp + 1;
 144                 tp->ldr = LDR;
 145                 tp->br = BR;
 146                 tp->addr = sym_addr;
 147                 offset = (grub_uint8_t *) tp - (grub_uint8_t *) place;
 148               }
 149
 150             if (!grub_arm_64_check_xxxx26_offset (offset))
 151                 return grub_error (GRUB_ERR_BAD_MODULE,
 152                                    "trampoline out of range");
 153
 154             grub_arm64_set_xxxx26_offset (place, offset);
 155           }
 156           break;
 157         default:
 158           return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
 159                              N_("relocation 0x%x is not implemented yet"),
 160                              ELF_R_TYPE (rel->r_info));
 161         }
 162     }
 163
 164   return GRUB_ERR_NONE;
 165 }