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 #define R_RELATIVE R_AARCH64_RELATIVE
  11
  12 #define R_NUM      R_AARCH64_NUM
  13
  14 #define ELF_START_ADDR 0x00400000
  15 #define ELF_PAGE_SIZE 0x1000
  16
  17 #define PCRELATIVE_DLLPLT 1
  18 #define RELOCATE_DLLPLT 1
  19
  20 #else /* !TARGET_DEFS_ONLY */
  21
  22 #include "tcc.h"
  23
  24 /* Returns 1 for a code relocation, 0 for a data relocation. For unknown
  25    relocations, returns -1. */
  26 int code_reloc (int reloc_type)
  27 {
  28     switch (reloc_type) {
  29         case R_AARCH64_ABS32:
  30         case R_AARCH64_ABS64:
  31         case R_AARCH64_PREL32:
  32         case R_AARCH64_MOVW_UABS_G0_NC:
  33         case R_AARCH64_MOVW_UABS_G1_NC:
  34         case R_AARCH64_MOVW_UABS_G2_NC:
  35         case R_AARCH64_MOVW_UABS_G3:
  36         case R_AARCH64_ADR_PREL_PG_HI21:
  37         case R_AARCH64_ADD_ABS_LO12_NC:
  38         case R_AARCH64_ADR_GOT_PAGE:
  39         case R_AARCH64_LD64_GOT_LO12_NC:
  40         case R_AARCH64_GLOB_DAT:
  41         case R_AARCH64_COPY:
  42             return 0;
  43
  44         case R_AARCH64_JUMP26:
  45         case R_AARCH64_CALL26:
  46         case R_AARCH64_JUMP_SLOT:
  47             return 1;
  48     }
  49
  50     tcc_error ("Unknown relocation type: %d", reloc_type);
  51     return -1;
  52 }
  53
  54 /* Returns an enumerator to describe whether and when the relocation needs a
  55    GOT and/or PLT entry to be created. See tcc.h for a description of the
  56    different values. */
  57 int gotplt_entry_type (int reloc_type)
  58 {
  59     switch (reloc_type) {
  60         case R_AARCH64_PREL32:
  61         case R_AARCH64_MOVW_UABS_G0_NC:
  62         case R_AARCH64_MOVW_UABS_G1_NC:
  63         case R_AARCH64_MOVW_UABS_G2_NC:
  64         case R_AARCH64_MOVW_UABS_G3:
  65         case R_AARCH64_ADR_PREL_PG_HI21:
  66         case R_AARCH64_ADD_ABS_LO12_NC:
  67         case R_AARCH64_GLOB_DAT:
  68         case R_AARCH64_JUMP_SLOT:
  69         case R_AARCH64_COPY:
  70             return NO_GOTPLT_ENTRY;
  71
  72         case R_AARCH64_ABS32:
  73         case R_AARCH64_ABS64:
  74         case R_AARCH64_JUMP26:
  75         case R_AARCH64_CALL26:
  76             return AUTO_GOTPLT_ENTRY;
  77
  78         case R_AARCH64_ADR_GOT_PAGE:
  79         case R_AARCH64_LD64_GOT_LO12_NC:
  80             return ALWAYS_GOTPLT_ENTRY;
  81     }
  82
  83     tcc_error ("Unknown relocation type: %d", reloc_type);
  84     return -1;
  85 }
  86
  87 ST_FUNC unsigned create_plt_entry(TCCState *s1, unsigned got_offset, struct sym_attr *attr)
  88 {
  89     Section *plt = s1->plt;
  90     uint8_t *p;
  91     unsigned plt_offset;
  92
  93     if (s1->output_type == TCC_OUTPUT_DLL)
  94         tcc_error("DLLs unimplemented!");
  95
  96     if (plt->data_offset == 0) {
  97         section_ptr_add(plt, 32);
  98     }
  99     plt_offset = plt->data_offset;
 100
 101     p = section_ptr_add(plt, 16);
 102     write32le(p, got_offset);
 103     write32le(p + 4, (uint64_t) got_offset >> 32);
 104     return plt_offset;
 105 }
 106
 107 /* relocate the PLT: compute addresses and offsets in the PLT now that final
 108    address for PLT and GOT are known (see fill_program_header) */
 109 ST_FUNC void relocate_plt(TCCState *s1)
 110 {
 111     uint8_t *p, *p_end;
 112
 113     if (!s1->plt)
 114       return;
 115
 116     p = s1->plt->data;
 117     p_end = p + s1->plt->data_offset;
 118
 119     if (p < p_end) {
 120         uint64_t plt = s1->plt->sh_addr;
 121         uint64_t got = s1->got->sh_addr;
 122         uint64_t off = (got >> 12) - (plt >> 12);
 123         if ((off + ((uint32_t)1 << 20)) >> 21)
 124             tcc_error("Failed relocating PLT (off=0x%lx, got=0x%lx, plt=0x%lx)", off, got, plt);
 125         write32le(p, 0xa9bf7bf0); // stp x16,x30,[sp,#-16]!
 126         write32le(p + 4, (0x90000010 | // adrp x16,...
 127                           (off & 0x1ffffc) << 3 | (off & 3) << 29));
 128         write32le(p + 8, (0xf9400211 | // ldr x17,[x16,#...]
 129                           (got & 0xff8) << 7));
 130         write32le(p + 12, (0x91000210 | // add x16,x16,#...
 131                            (got & 0xfff) << 10));
 132         write32le(p + 16, 0xd61f0220); // br x17
 133         write32le(p + 20, 0xd503201f); // nop
 134         write32le(p + 24, 0xd503201f); // nop
 135         write32le(p + 28, 0xd503201f); // nop
 136         p += 32;
 137         while (p < p_end) {
 138             uint64_t pc = plt + (p - s1->plt->data);
 139             uint64_t addr = got + read64le(p);
 140             uint64_t off = (addr >> 12) - (pc >> 12);
 141             if ((off + ((uint32_t)1 << 20)) >> 21)
 142                 tcc_error("Failed relocating PLT (off=0x%lx, addr=0x%lx, pc=0x%lx)", off, addr, pc);
 143             write32le(p, (0x90000010 | // adrp x16,...
 144                           (off & 0x1ffffc) << 3 | (off & 3) << 29));
 145             write32le(p + 4, (0xf9400211 | // ldr x17,[x16,#...]
 146                               (addr & 0xff8) << 7));
 147             write32le(p + 8, (0x91000210 | // add x16,x16,#...
 148                               (addr & 0xfff) << 10));
 149             write32le(p + 12, 0xd61f0220); // br x17
 150             p += 16;
 151         }
 152     }
 153 }
 154
 155 void relocate_init(Section *sr) {}
 156
 157 void relocate(TCCState *s1, ElfW_Rel *rel, int type, unsigned char *ptr, addr_t addr, addr_t val)
 158 {
 159     int sym_index = ELFW(R_SYM)(rel->r_info);
 160 #ifdef DEBUG_RELOC
 161     ElfW(Sym) *sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
 162 #endif
 163
 164     switch(type) {
 165         case R_AARCH64_ABS64:
 166             write64le(ptr, val);
 167             return;
 168         case R_AARCH64_ABS32:
 169             write32le(ptr, val);
 170             return;
 171         case R_AARCH64_PREL32:
 172             write32le(ptr, val - addr);
 173             return;
 174         case R_AARCH64_MOVW_UABS_G0_NC:
 175             write32le(ptr, ((read32le(ptr) & 0xffe0001f) |
 176                             (val & 0xffff) << 5));
 177             return;
 178         case R_AARCH64_MOVW_UABS_G1_NC:
 179             write32le(ptr, ((read32le(ptr) & 0xffe0001f) |
 180                             (val >> 16 & 0xffff) << 5));
 181             return;
 182         case R_AARCH64_MOVW_UABS_G2_NC:
 183             write32le(ptr, ((read32le(ptr) & 0xffe0001f) |
 184                             (val >> 32 & 0xffff) << 5));
 185             return;
 186         case R_AARCH64_MOVW_UABS_G3:
 187             write32le(ptr, ((read32le(ptr) & 0xffe0001f) |
 188                             (val >> 48 & 0xffff) << 5));
 189             return;
 190         case R_AARCH64_ADR_PREL_PG_HI21: {
 191             uint64_t off = (val >> 12) - (addr >> 12);
 192             if ((off + ((uint64_t)1 << 20)) >> 21)
 193                 tcc_error("R_AARCH64_ADR_PREL_PG_HI21 relocation failed");
 194             write32le(ptr, ((read32le(ptr) & 0x9f00001f) |
 195                             (off & 0x1ffffc) << 3 | (off & 3) << 29));
 196             return;
 197         }
 198         case R_AARCH64_ADD_ABS_LO12_NC:
 199             write32le(ptr, ((read32le(ptr) & 0xffc003ff) |
 200                             (val & 0xfff) << 10));
 201             return;
 202         case R_AARCH64_JUMP26:
 203         case R_AARCH64_CALL26:
 204 #ifdef DEBUG_RELOC
 205             printf ("reloc %d @ 0x%lx: val=0x%lx name=%s\n", type, addr, val,
 206                     (char *) symtab_section->link->data + sym->st_name);
 207 #endif
 208             if (((val - addr) + ((uint64_t)1 << 27)) & ~(uint64_t)0xffffffc)
 209                 tcc_error("R_AARCH64_(JUMP|CALL)26 relocation failed"
 210                           " (val=%lx, addr=%lx)", val, addr);
 211             write32le(ptr, (0x14000000 |
 212                             (uint32_t)(type == R_AARCH64_CALL26) << 31 |
 213                             ((val - addr) >> 2 & 0x3ffffff)));
 214             return;
 215         case R_AARCH64_ADR_GOT_PAGE: {
 216             uint64_t off =
 217                 (((s1->got->sh_addr +
 218                    s1->sym_attrs[sym_index].got_offset) >> 12) - (addr >> 12));
 219             if ((off + ((uint64_t)1 << 20)) >> 21)
 220                 tcc_error("R_AARCH64_ADR_GOT_PAGE relocation failed");
 221             write32le(ptr, ((read32le(ptr) & 0x9f00001f) |
 222                             (off & 0x1ffffc) << 3 | (off & 3) << 29));
 223             return;
 224         }
 225         case R_AARCH64_LD64_GOT_LO12_NC:
 226             write32le(ptr,
 227                       ((read32le(ptr) & 0xfff803ff) |
 228                        ((s1->got->sh_addr +
 229                          s1->sym_attrs[sym_index].got_offset) & 0xff8) << 7));
 230             return;
 231         case R_AARCH64_COPY:
 232             return;
 233         case R_AARCH64_GLOB_DAT:
 234         case R_AARCH64_JUMP_SLOT:
 235             /* They don't need addend */
 236 #ifdef DEBUG_RELOC
 237             printf ("reloc %d @ 0x%lx: val=0x%lx name=%s\n", type, addr,
 238                     val - rel->r_addend,
 239                     (char *) symtab_section->link->data + sym->st_name);
 240 #endif
 241             write64le(ptr, val - rel->r_addend);
 242             return;
 243         default:
 244             fprintf(stderr, "FIXME: handle reloc type %x at %x [%p] to %x\n",
 245                     type, (unsigned)addr, ptr, (unsigned)val);
 246             return;
 247     }
 248 }
 249
 250 #endif /* !TARGET_DEFS_ONLY */