arm64-link.c

   1 #ifdef TARGET_DEFS_ONLY
   2
   3 #define EM_TCC_TARGET EM_AARCH64
   4
   5 #define R_DATA_32  R_AARCH64_ABS32
   6 #define R_DATA_PTR R_AARCH64_ABS64
   7 #define R_JMP_SLOT R_AARCH64_JUMP_SLOT
   8 #define R_GLOB_DAT R_AARCH64_GLOB_DAT
   9 #define R_COPY     R_AARCH64_COPY
  10
  11 #define R_NUM      R_AARCH64_NUM
  12
  13 #define ELF_START_ADDR 0x00400000
  14 #define ELF_PAGE_SIZE 0x1000
  15
  16 #define PCRELATIVE_DLLPLT 1
  17 #define RELOCATE_DLLPLT 1
  18
  19 #else /* !TARGET_DEFS_ONLY */
  20
  21 #include "tcc.h"
  22
  23 /* Returns 1 for a code relocation, 0 for a data relocation. For unknown
  24    relocations, returns -1. */
  25 int code_reloc (int reloc_type)
  26 {
  27     switch (reloc_type) {
  28         case R_AARCH64_ABS32:
  29         case R_AARCH64_ABS64:
  30         case R_AARCH64_MOVW_UABS_G0_NC:
  31         case R_AARCH64_MOVW_UABS_G1_NC:
  32         case R_AARCH64_MOVW_UABS_G2_NC:
  33         case R_AARCH64_MOVW_UABS_G3:
  34         case R_AARCH64_ADR_PREL_PG_HI21:
  35         case R_AARCH64_ADD_ABS_LO12_NC:
  36         case R_AARCH64_ADR_GOT_PAGE:
  37         case R_AARCH64_LD64_GOT_LO12_NC:
  38         case R_AARCH64_GLOB_DAT:
  39         case R_AARCH64_COPY:
  40             return 0;
  41
  42         case R_AARCH64_JUMP26:
  43         case R_AARCH64_CALL26:
  44         case R_AARCH64_JUMP_SLOT:
  45             return 1;
  46     }
  47
  48     tcc_error ("Unknown relocation type: %d", reloc_type);
  49     return -1;
  50 }
  51
  52 /* Returns an enumerator to describe wether and when the relocation needs a
  53    GOT and/or PLT entry to be created. See tcc.h for a description of the
  54    different values. */
  55 int gotplt_entry_type (int reloc_type)
  56 {
  57     switch (reloc_type) {
  58         case R_AARCH64_ABS32:
  59         case R_AARCH64_ABS64:
  60         case R_AARCH64_MOVW_UABS_G0_NC:
  61         case R_AARCH64_MOVW_UABS_G1_NC:
  62         case R_AARCH64_MOVW_UABS_G2_NC:
  63         case R_AARCH64_MOVW_UABS_G3:
  64         case R_AARCH64_ADR_PREL_PG_HI21:
  65         case R_AARCH64_ADD_ABS_LO12_NC:
  66         case R_AARCH64_GLOB_DAT:
  67         case R_AARCH64_JUMP_SLOT:
  68         case R_AARCH64_COPY:
  69             return NO_GOTPLT_ENTRY;
  70
  71         case R_AARCH64_JUMP26:
  72         case R_AARCH64_CALL26:
  73             return AUTO_GOTPLT_ENTRY;
  74
  75         case R_AARCH64_ADR_GOT_PAGE:
  76         case R_AARCH64_LD64_GOT_LO12_NC:
  77             return ALWAYS_GOTPLT_ENTRY;
  78     }
  79
  80     tcc_error ("Unknown relocation type: %d", reloc_type);
  81     return -1;
  82 }
  83
  84 ST_FUNC unsigned create_plt_entry(TCCState *s1, unsigned got_offset, struct sym_attr *attr)
  85 {
  86     Section *plt = s1->plt;
  87     uint8_t *p;
  88     unsigned plt_offset;
  89
  90     if (s1->output_type == TCC_OUTPUT_DLL)
  91         tcc_error("DLLs unimplemented!");
  92
  93     if (plt->data_offset == 0) {
  94         section_ptr_add(plt, 32);
  95     }
  96     plt_offset = plt->data_offset;
  97
  98     p = section_ptr_add(plt, 16);
  99     write32le(p, got_offset);
 100     write32le(p + 4, (uint64_t) got_offset >> 32);
 101     return plt_offset;
 102 }
 103
 104 /* relocate the PLT: compute addresses and offsets in the PLT now that final
 105    address for PLT and GOT are known (see fill_program_header) */
 106 ST_FUNC void relocate_plt(TCCState *s1)
 107 {
 108     uint8_t *p, *p_end;
 109
 110     if (!s1->plt)
 111       return;
 112
 113     p = s1->plt->data;
 114     p_end = p + s1->plt->data_offset;
 115
 116     if (p < p_end) {
 117         uint64_t plt = s1->plt->sh_addr;
 118         uint64_t got = s1->got->sh_addr;
 119         uint64_t off = (got >> 12) - (plt >> 12);
 120         if ((off + ((uint32_t)1 << 20)) >> 21)
 121             tcc_error("Failed relocating PLT (off=0x%lx, got=0x%lx, plt=0x%lx)", off, got, plt);
 122         write32le(p, 0xa9bf7bf0); // stp x16,x30,[sp,#-16]!
 123         write32le(p + 4, (0x90000010 | // adrp x16,...
 124                           (off & 0x1ffffc) << 3 | (off & 3) << 29));
 125         write32le(p + 8, (0xf9400211 | // ldr x17,[x16,#...]
 126                           (got & 0xff8) << 7));
 127         write32le(p + 12, (0x91000210 | // add x16,x16,#...
 128                            (got & 0xfff) << 10));
 129         write32le(p + 16, 0xd61f0220); // br x17
 130         write32le(p + 20, 0xd503201f); // nop
 131         write32le(p + 24, 0xd503201f); // nop
 132         write32le(p + 28, 0xd503201f); // nop
 133         p += 32;
 134         while (p < p_end) {
 135             uint64_t pc = plt + (p - s1->plt->data);
 136             uint64_t addr = got + read64le(p);
 137             uint64_t off = (addr >> 12) - (pc >> 12);
 138             if ((off + ((uint32_t)1 << 20)) >> 21)
 139                 tcc_error("Failed relocating PLT (off=0x%lx, addr=0x%lx, pc=0x%lx)", off, addr, pc);
 140             write32le(p, (0x90000010 | // adrp x16,...
 141                           (off & 0x1ffffc) << 3 | (off & 3) << 29));
 142             write32le(p + 4, (0xf9400211 | // ldr x17,[x16,#...]
 143                               (addr & 0xff8) << 7));
 144             write32le(p + 8, (0x91000210 | // add x16,x16,#...
 145                               (addr & 0xfff) << 10));
 146             write32le(p + 12, 0xd61f0220); // br x17
 147             p += 16;
 148         }
 149     }
 150 }
 151
 152 void relocate_init(Section *sr) {}
 153
 154 void relocate(TCCState *s1, ElfW_Rel *rel, int type, char *ptr, addr_t addr, addr_t val)
 155 {
 156     int sym_index = ELFW(R_SYM)(rel->r_info);
 157 #ifdef DEBUG_RELOC
 158     ElfW(Sym) *sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
 159 #endif
 160
 161     switch(type) {
 162         case R_AARCH64_ABS64:
 163             write64le(ptr, val);
 164             return;
 165         case R_AARCH64_ABS32:
 166             write32le(ptr, val);
 167             return;
 168         case R_AARCH64_MOVW_UABS_G0_NC:
 169             write32le(ptr, ((read32le(ptr) & 0xffe0001f) |
 170                             (val & 0xffff) << 5));
 171             return;
 172         case R_AARCH64_MOVW_UABS_G1_NC:
 173             write32le(ptr, ((read32le(ptr) & 0xffe0001f) |
 174                             (val >> 16 & 0xffff) << 5));
 175             return;
 176         case R_AARCH64_MOVW_UABS_G2_NC:
 177             write32le(ptr, ((read32le(ptr) & 0xffe0001f) |
 178                             (val >> 32 & 0xffff) << 5));
 179             return;
 180         case R_AARCH64_MOVW_UABS_G3:
 181             write32le(ptr, ((read32le(ptr) & 0xffe0001f) |
 182                             (val >> 48 & 0xffff) << 5));
 183             return;
 184         case R_AARCH64_ADR_PREL_PG_HI21: {
 185             uint64_t off = (val >> 12) - (addr >> 12);
 186             if ((off + ((uint64_t)1 << 20)) >> 21)
 187                 tcc_error("R_AARCH64_ADR_PREL_PG_HI21 relocation failed");
 188             write32le(ptr, ((read32le(ptr) & 0x9f00001f) |
 189                             (off & 0x1ffffc) << 3 | (off & 3) << 29));
 190             return;
 191         }
 192         case R_AARCH64_ADD_ABS_LO12_NC:
 193             write32le(ptr, ((read32le(ptr) & 0xffc003ff) |
 194                             (val & 0xfff) << 10));
 195             return;
 196         case R_AARCH64_JUMP26:
 197         case R_AARCH64_CALL26:
 198 #ifdef DEBUG_RELOC
 199             printf ("reloc %d @ 0x%lx: val=0x%lx name=%s\n", type, addr, val,
 200                     (char *) symtab_section->link->data + sym->st_name);
 201 #endif
 202             if (((val - addr) + ((uint64_t)1 << 27)) & ~(uint64_t)0xffffffc)
 203                 tcc_error("R_AARCH64_(JUMP|CALL)26 relocation failed"
 204                           " (val=%lx, addr=%lx)", val, addr);
 205             write32le(ptr, (0x14000000 |
 206                             (uint32_t)(type == R_AARCH64_CALL26) << 31 |
 207                             ((val - addr) >> 2 & 0x3ffffff)));
 208             return;
 209         case R_AARCH64_ADR_GOT_PAGE: {
 210             uint64_t off =
 211                 (((s1->got->sh_addr +
 212                    s1->sym_attrs[sym_index].got_offset) >> 12) - (addr >> 12));
 213             if ((off + ((uint64_t)1 << 20)) >> 21)
 214                 tcc_error("R_AARCH64_ADR_GOT_PAGE relocation failed");
 215             write32le(ptr, ((read32le(ptr) & 0x9f00001f) |
 216                             (off & 0x1ffffc) << 3 | (off & 3) << 29));
 217             return;
 218         }
 219         case R_AARCH64_LD64_GOT_LO12_NC:
 220             write32le(ptr,
 221                       ((read32le(ptr) & 0xfff803ff) |
 222                        ((s1->got->sh_addr +
 223                          s1->sym_attrs[sym_index].got_offset) & 0xff8) << 7));
 224             return;
 225         case R_AARCH64_COPY:
 226             return;
 227         case R_AARCH64_GLOB_DAT:
 228         case R_AARCH64_JUMP_SLOT:
 229             /* They don't need addend */
 230 #ifdef DEBUG_RELOC
 231             printf ("reloc %d @ 0x%lx: val=0x%lx name=%s\n", type, addr,
 232                     val - rel->r_addend,
 233                     (char *) symtab_section->link->data + sym->st_name);
 234 #endif
 235             write64le(ptr, val - rel->r_addend);
 236             return;
 237         default:
 238             fprintf(stderr, "FIXME: handle reloc type %x at %x [%p] to %x\n",
 239                     type, (unsigned)addr, ptr, (unsigned)val);
 240             return;
 241     }
 242 }
 243
 244 #endif /* !TARGET_DEFS_ONLY */