riscv64-link.c

   1 #ifdef TARGET_DEFS_ONLY
   2
   3 #define EM_TCC_TARGET EM_RISCV
   4
   5 #define R_DATA_32  R_RISCV_32
   6 #define R_DATA_PTR R_RISCV_64
   7 #define R_JMP_SLOT R_RISCV_JUMP_SLOT
   8 #define R_GLOB_DAT R_RISCV_64
   9 #define R_COPY     R_RISCV_COPY
  10 #define R_RELATIVE R_RISCV_RELATIVE
  11
  12 #define R_NUM      R_RISCV_NUM
  13
  14 #define ELF_START_ADDR 0x00010000
  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 //#define DEBUG_RELOC
  23 #include "tcc.h"
  24
  25 /* Returns 1 for a code relocation, 0 for a data relocation. For unknown
  26    relocations, returns -1. */
  27 int code_reloc (int reloc_type)
  28 {
  29     switch (reloc_type) {
  30
  31     case R_RISCV_BRANCH:
  32     case R_RISCV_CALL:
  33     case R_RISCV_JAL:
  34         return 1;
  35
  36     case R_RISCV_GOT_HI20:
  37     case R_RISCV_PCREL_HI20:
  38     case R_RISCV_PCREL_LO12_I:
  39     case R_RISCV_PCREL_LO12_S:
  40     case R_RISCV_32_PCREL:
  41     case R_RISCV_SET6:
  42     case R_RISCV_SET8:
  43     case R_RISCV_SET16:
  44     case R_RISCV_SUB6:
  45     case R_RISCV_ADD16:
  46     case R_RISCV_ADD32:
  47     case R_RISCV_ADD64:
  48     case R_RISCV_SUB8:
  49     case R_RISCV_SUB16:
  50     case R_RISCV_SUB32:
  51     case R_RISCV_SUB64:
  52     case R_RISCV_32:
  53     case R_RISCV_64:
  54         return 0;
  55
  56     case R_RISCV_CALL_PLT:
  57         return 1;
  58     }
  59     return -1;
  60 }
  61
  62 /* Returns an enumerator to describe whether and when the relocation needs a
  63    GOT and/or PLT entry to be created. See tcc.h for a description of the
  64    different values. */
  65 int gotplt_entry_type (int reloc_type)
  66 {
  67     switch (reloc_type) {
  68     case R_RISCV_ALIGN:
  69     case R_RISCV_RELAX:
  70     case R_RISCV_RVC_BRANCH:
  71     case R_RISCV_RVC_JUMP:
  72     case R_RISCV_JUMP_SLOT:
  73     case R_RISCV_SET6:
  74     case R_RISCV_SET8:
  75     case R_RISCV_SET16:
  76     case R_RISCV_SUB6:
  77     case R_RISCV_ADD16:
  78     case R_RISCV_SUB8:
  79     case R_RISCV_SUB16:
  80         return NO_GOTPLT_ENTRY;
  81
  82     case R_RISCV_BRANCH:
  83     case R_RISCV_CALL:
  84     case R_RISCV_PCREL_HI20:
  85     case R_RISCV_PCREL_LO12_I:
  86     case R_RISCV_PCREL_LO12_S:
  87     case R_RISCV_32_PCREL:
  88     case R_RISCV_ADD32:
  89     case R_RISCV_ADD64:
  90     case R_RISCV_SUB32:
  91     case R_RISCV_SUB64:
  92     case R_RISCV_32:
  93     case R_RISCV_64:
  94     case R_RISCV_JAL:
  95     case R_RISCV_CALL_PLT:
  96         return AUTO_GOTPLT_ENTRY;
  97
  98     case R_RISCV_GOT_HI20:
  99         return ALWAYS_GOTPLT_ENTRY;
 100     }
 101     return -1;
 102 }
 103
 104 ST_FUNC unsigned create_plt_entry(TCCState *s1, unsigned got_offset, struct sym_attr *attr)
 105 {
 106     Section *plt = s1->plt;
 107     uint8_t *p;
 108     unsigned plt_offset;
 109
 110     if (plt->data_offset == 0)
 111         section_ptr_add(plt, 32);
 112     plt_offset = plt->data_offset;
 113
 114     p = section_ptr_add(plt, 16);
 115     write64le(p, got_offset);
 116     return plt_offset;
 117 }
 118
 119 /* relocate the PLT: compute addresses and offsets in the PLT now that final
 120    address for PLT and GOT are known (see fill_program_header) */
 121 ST_FUNC void relocate_plt(TCCState *s1)
 122 {
 123     uint8_t *p, *p_end;
 124
 125     if (!s1->plt)
 126       return;
 127
 128     p = s1->plt->data;
 129     p_end = p + s1->plt->data_offset;
 130
 131     if (p < p_end) {
 132         uint64_t plt = s1->plt->sh_addr;
 133         uint64_t got = s1->got->sh_addr;
 134         uint64_t off = (got - plt + 0x800) >> 12;
 135         if ((off + ((uint32_t)1 << 20)) >> 21)
 136             tcc_error_noabort("Failed relocating PLT (off=0x%lx, got=0x%lx, plt=0x%lx)", (long)off, (long)got, (long)plt);
 137         write32le(p, 0x397 | (off << 12)); // auipc t2, %pcrel_hi(got)
 138         write32le(p + 4, 0x41c30333); // sub t1, t1, t3
 139         write32le(p + 8, 0x0003be03   // ld t3, %pcrel_lo(got)(t2)
 140                          | (((got - plt) & 0xfff) << 20));
 141         write32le(p + 12, 0xfd430313); // addi t1, t1, -(32+12)
 142         write32le(p + 16, 0x00038293   // addi t0, t2, %pcrel_lo(got)
 143                           | (((got - plt) & 0xfff) << 20));
 144         write32le(p + 20, 0x00135313); // srli t1, t1, log2(16/PTRSIZE)
 145         write32le(p + 24, 0x0082b283); // ld t0, PTRSIZE(t0)
 146         write32le(p + 28, 0x000e0067); // jr t3
 147         p += 32;
 148         while (p < p_end) {
 149             uint64_t pc = plt + (p - s1->plt->data);
 150             uint64_t addr = got + read64le(p);
 151             uint64_t off = (addr - pc + 0x800) >> 12;
 152             if ((off + ((uint32_t)1 << 20)) >> 21)
 153                 tcc_error_noabort("Failed relocating PLT (off=0x%lx, addr=0x%lx, pc=0x%lx)", (long)off, (long)addr, (long)pc);
 154             write32le(p, 0xe17 | (off << 12)); // auipc t3, %pcrel_hi(func@got)
 155             write32le(p + 4, 0x000e3e03 // ld t3, %pcrel_lo(func@got)(t3)
 156                              | (((addr - pc) & 0xfff) << 20));
 157             write32le(p + 8, 0x000e0367); // jalr t1, t3
 158             write32le(p + 12, 0x00000013); // nop
 159             p += 16;
 160         }
 161     }
 162
 163     if (s1->plt->reloc) {
 164         ElfW_Rel *rel;
 165         p = s1->got->data;
 166         for_each_elem(s1->plt->reloc, 0, rel, ElfW_Rel) {
 167             write64le(p + rel->r_offset, s1->plt->sh_addr);
 168         }
 169     }
 170 }
 171
 172 void relocate(TCCState *s1, ElfW_Rel *rel, int type, unsigned char *ptr,
 173               addr_t addr, addr_t val)
 174 {
 175     uint64_t off64;
 176     uint32_t off32;
 177     int sym_index = ELFW(R_SYM)(rel->r_info), esym_index;
 178     ElfW(Sym) *sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
 179
 180     switch(type) {
 181     case R_RISCV_ALIGN:
 182     case R_RISCV_RELAX:
 183         return;
 184
 185     case R_RISCV_BRANCH:
 186         off64 = val - addr;
 187         if ((off64 + (1 << 12)) & ~(uint64_t)0x1ffe)
 188           tcc_error_noabort("R_RISCV_BRANCH relocation failed"
 189                     " (val=%lx, addr=%lx)", (long)val, (long)addr);
 190         off32 = off64 >> 1;
 191         write32le(ptr, (read32le(ptr) & ~0xfe000f80)
 192                        | ((off32 & 0x800) << 20)
 193                        | ((off32 & 0x3f0) << 21)
 194                        | ((off32 & 0x00f) << 8)
 195                        | ((off32 & 0x400) >> 3));
 196         return;
 197     case R_RISCV_JAL:
 198         off64 = val - addr;
 199         if ((off64 + (1 << 21)) & ~(((uint64_t)1 << 22) - 2))
 200           tcc_error_noabort("R_RISCV_JAL relocation failed"
 201                     " (val=%lx, addr=%lx)", (long)val, (long)addr);
 202         off32 = off64;
 203         write32le(ptr, (read32le(ptr) & 0xfff)
 204                        | (((off32 >> 12) &  0xff) << 12)
 205                        | (((off32 >> 11) &     1) << 20)
 206                        | (((off32 >>  1) & 0x3ff) << 21)
 207                        | (((off32 >> 20) &     1) << 31));
 208         return;
 209     case R_RISCV_CALL:
 210     case R_RISCV_CALL_PLT:
 211         write32le(ptr, (read32le(ptr) & 0xfff)
 212                        | ((val - addr + 0x800) & ~0xfff));
 213         write32le(ptr + 4, (read32le(ptr + 4) & 0xfffff)
 214                            | (((val - addr) & 0xfff) << 20));
 215         return;
 216     case R_RISCV_PCREL_HI20:
 217 #ifdef DEBUG_RELOC
 218         printf("PCREL_HI20: val=%lx addr=%lx\n", (long)val, (long)addr);
 219 #endif
 220         off64 = (int64_t)(val - addr + 0x800) >> 12;
 221         if ((off64 + ((uint64_t)1 << 20)) >> 21)
 222           tcc_error_noabort("R_RISCV_PCREL_HI20 relocation failed: off=%lx cond=%lx sym=%s",
 223                     (long)off64, (long)((int64_t)(off64 + ((uint64_t)1 << 20)) >> 21),
 224                     symtab_section->link->data + sym->st_name);
 225         write32le(ptr, (read32le(ptr) & 0xfff)
 226                        | ((off64 & 0xfffff) << 12));
 227         last_hi.addr = addr;
 228         last_hi.val = val;
 229         return;
 230     case R_RISCV_GOT_HI20:
 231         val = s1->got->sh_addr + get_sym_attr(s1, sym_index, 0)->got_offset;
 232         off64 = (int64_t)(val - addr + 0x800) >> 12;
 233         if ((off64 + ((uint64_t)1 << 20)) >> 21)
 234           tcc_error_noabort("R_RISCV_GOT_HI20 relocation failed");
 235         last_hi.addr = addr;
 236         last_hi.val = val;
 237         write32le(ptr, (read32le(ptr) & 0xfff)
 238                        | ((off64 & 0xfffff) << 12));
 239         return;
 240     case R_RISCV_PCREL_LO12_I:
 241 #ifdef DEBUG_RELOC
 242         printf("PCREL_LO12_I: val=%lx addr=%lx\n", (long)val, (long)addr);
 243 #endif
 244         if (val != last_hi.addr)
 245           tcc_error_noabort("unsupported hi/lo pcrel reloc scheme");
 246         val = last_hi.val;
 247         addr = last_hi.addr;
 248         write32le(ptr, (read32le(ptr) & 0xfffff)
 249                        | (((val - addr) & 0xfff) << 20));
 250         return;
 251     case R_RISCV_PCREL_LO12_S:
 252         if (val != last_hi.addr)
 253           tcc_error_noabort("unsupported hi/lo pcrel reloc scheme");
 254         val = last_hi.val;
 255         addr = last_hi.addr;
 256         off32 = val - addr;
 257         write32le(ptr, (read32le(ptr) & ~0xfe000f80)
 258                        | ((off32 & 0xfe0) << 20)
 259                        | ((off32 & 0x01f) << 7));
 260         return;
 261
 262     case R_RISCV_RVC_BRANCH:
 263         off64 = (val - addr);
 264         if ((off64 + (1 << 8)) & ~(uint64_t)0x1fe)
 265           tcc_error_noabort("R_RISCV_RVC_BRANCH relocation failed"
 266                     " (val=%lx, addr=%lx)", (long)val, (long)addr);
 267         off32 = off64;
 268         write16le(ptr, (read16le(ptr) & 0xe383)
 269                        | (((off32 >> 5) & 1) << 2)
 270                        | (((off32 >> 1) & 3) << 3)
 271                        | (((off32 >> 6) & 3) << 5)
 272                        | (((off32 >> 3) & 3) << 10)
 273                        | (((off32 >> 8) & 1) << 12));
 274         return;
 275     case R_RISCV_RVC_JUMP:
 276         off64 = (val - addr);
 277         if ((off64 + (1 << 11)) & ~(uint64_t)0xffe)
 278           tcc_error_noabort("R_RISCV_RVC_BRANCH relocation failed"
 279                     " (val=%lx, addr=%lx)", (long)val, (long)addr);
 280         off32 = off64;
 281         write16le(ptr, (read16le(ptr) & 0xe003)
 282                        | (((off32 >>  5) & 1) << 2)
 283                        | (((off32 >>  1) & 7) << 3)
 284                        | (((off32 >>  7) & 1) << 6)
 285                        | (((off32 >>  6) & 1) << 7)
 286                        | (((off32 >> 10) & 1) << 8)
 287                        | (((off32 >>  8) & 3) << 9)
 288                        | (((off32 >>  4) & 1) << 11)
 289                        | (((off32 >> 11) & 1) << 12));
 290         return;
 291
 292     case R_RISCV_32:
 293         if (s1->output_type & TCC_OUTPUT_DYN) {
 294             /* XXX: this logic may depend on TCC's codegen
 295                now TCC uses R_RISCV_RELATIVE even for a 64bit pointer */
 296             qrel->r_offset = rel->r_offset;
 297             qrel->r_info = ELFW(R_INFO)(0, R_RISCV_RELATIVE);
 298             /* Use sign extension! */
 299             qrel->r_addend = (int)read32le(ptr) + val;
 300             qrel++;
 301         }
 302         add32le(ptr, val);
 303         return;
 304     case R_RISCV_64:
 305         if (s1->output_type & TCC_OUTPUT_DYN) {
 306             esym_index = get_sym_attr(s1, sym_index, 0)->dyn_index;
 307             qrel->r_offset = rel->r_offset;
 308             if (esym_index) {
 309                 qrel->r_info = ELFW(R_INFO)(esym_index, R_RISCV_64);
 310                 qrel->r_addend = rel->r_addend;
 311                 qrel++;
 312                 break;
 313             } else {
 314                 qrel->r_info = ELFW(R_INFO)(0, R_RISCV_RELATIVE);
 315                 qrel->r_addend = read64le(ptr) + val;
 316                 qrel++;
 317             }
 318         }
 319     case R_RISCV_JUMP_SLOT:
 320         add64le(ptr, val);
 321         return;
 322     case R_RISCV_ADD64:
 323         write64le(ptr, read64le(ptr) + val);
 324         return;
 325     case R_RISCV_ADD32:
 326         write32le(ptr, read32le(ptr) + val);
 327         return;
 328     case R_RISCV_SUB64:
 329         write64le(ptr, read64le(ptr) - val);
 330         return;
 331     case R_RISCV_SUB32:
 332         write32le(ptr, read32le(ptr) - val);
 333         return;
 334     case R_RISCV_ADD16:
 335         write16le(ptr, read16le(ptr) + val);
 336         return;
 337     case R_RISCV_SUB8:
 338         *ptr -= val;
 339         return;
 340     case R_RISCV_SUB16:
 341         write16le(ptr, read16le(ptr) - val);
 342         return;
 343     case R_RISCV_SET6:
 344         *ptr = (*ptr & ~0x3f) | (val & 0x3f);
 345         return;
 346     case R_RISCV_SET8:
 347         *ptr = (*ptr & ~0xff) | (val & 0xff);
 348         return;
 349     case R_RISCV_SET16:
 350         *ptr = (*ptr & ~0xffff) | (val & 0xffff);
 351         return;
 352     case R_RISCV_SUB6:
 353         *ptr = (*ptr & ~0x3f) | ((*ptr - val) & 0x3f);
 354         return;
 355
 356     case R_RISCV_32_PCREL:
 357     case R_RISCV_COPY:
 358         /* XXX */
 359         return;
 360
 361     default:
 362         fprintf(stderr, "FIXME: handle reloc type %x at %x [%p] to %x\n",
 363                 type, (unsigned)addr, ptr, (unsigned)val);
 364         return;
 365     }
 366 }
 367 #endif