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_SUB6:
  43     case R_RISCV_ADD16:
  44     case R_RISCV_ADD32:
  45     case R_RISCV_ADD64:
  46     case R_RISCV_SUB16:
  47     case R_RISCV_SUB32:
  48     case R_RISCV_SUB64:
  49     case R_RISCV_32:
  50     case R_RISCV_64:
  51         return 0;
  52
  53     case R_RISCV_CALL_PLT:
  54         return 1;
  55     }
  56     tcc_error ("Unknown relocation type in code_reloc: %d", reloc_type);
  57     return -1;
  58 }
  59
  60 /* Returns an enumerator to describe whether and when the relocation needs a
  61    GOT and/or PLT entry to be created. See tcc.h for a description of the
  62    different values. */
  63 int gotplt_entry_type (int reloc_type)
  64 {
  65     switch (reloc_type) {
  66     case R_RISCV_ALIGN:
  67     case R_RISCV_RELAX:
  68     case R_RISCV_RVC_BRANCH:
  69     case R_RISCV_RVC_JUMP:
  70     case R_RISCV_JUMP_SLOT:
  71     case R_RISCV_SET6:
  72     case R_RISCV_SUB6:
  73     case R_RISCV_ADD16:
  74     case R_RISCV_SUB16:
  75         return NO_GOTPLT_ENTRY;
  76
  77     case R_RISCV_BRANCH:
  78     case R_RISCV_CALL:
  79     case R_RISCV_PCREL_HI20:
  80     case R_RISCV_PCREL_LO12_I:
  81     case R_RISCV_PCREL_LO12_S:
  82     case R_RISCV_32_PCREL:
  83     case R_RISCV_ADD32:
  84     case R_RISCV_ADD64:
  85     case R_RISCV_SUB32:
  86     case R_RISCV_SUB64:
  87     case R_RISCV_32:
  88     case R_RISCV_64:
  89     case R_RISCV_JAL:
  90         return AUTO_GOTPLT_ENTRY;
  91
  92     case R_RISCV_GOT_HI20:
  93     case R_RISCV_CALL_PLT:
  94         return ALWAYS_GOTPLT_ENTRY;
  95     }
  96
  97     tcc_error ("Unknown relocation type: %d", reloc_type);
  98     return -1;
  99 }
 100
 101 ST_FUNC unsigned create_plt_entry(TCCState *s1, unsigned got_offset, struct sym_attr *attr)
 102 {
 103     Section *plt = s1->plt;
 104     uint8_t *p;
 105     unsigned plt_offset;
 106
 107     if (s1->output_type == TCC_OUTPUT_DLL)
 108         tcc_error("DLLs unimplemented!");
 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("Failed relocating PLT (off=0x%lx, got=0x%lx, plt=0x%lx)", off, got, 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("Failed relocating PLT (off=0x%lx, addr=0x%lx, pc=0x%lx)", off, addr, 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
 164 void relocate_init(Section *sr) {}
 165
 166 void relocate_fini(Section *sr)
 167 {
 168 }
 169
 170 struct pcrel_hi {
 171     addr_t addr, val;
 172 };
 173 static struct pcrel_hi last_hi;
 174
 175 void relocate(TCCState *s1, ElfW_Rel *rel, int type, unsigned char *ptr,
 176               addr_t addr, addr_t val)
 177 {
 178     uint64_t off64;
 179     uint32_t off32;
 180     int sym_index = ELFW(R_SYM)(rel->r_info);
 181     ElfW(Sym) *sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
 182
 183     switch(type) {
 184     case R_RISCV_ALIGN:
 185     case R_RISCV_RELAX:
 186         return;
 187
 188     case R_RISCV_BRANCH:
 189         off64 = val - addr;
 190         if ((off64 + (1 << 12)) & ~(uint64_t)0x1ffe)
 191           tcc_error("R_RISCV_BRANCH relocation failed"
 192                     " (val=%lx, addr=%lx)", val, addr);
 193         off32 = off64 >> 1;
 194         write32le(ptr, (read32le(ptr) & ~0xfe000f80)
 195                        | ((off32 & 0x800) << 20)
 196                        | ((off32 & 0x3f0) << 21)
 197                        | ((off32 & 0x00f) << 8)
 198                        | ((off32 & 0x400) >> 3));
 199         return;
 200     case R_RISCV_JAL:
 201         off64 = val - addr;
 202         if ((off64 + (1 << 21)) & ~(((uint64_t)1 << 22) - 2))
 203           tcc_error("R_RISCV_JAL relocation failed"
 204                     " (val=%lx, addr=%lx)", val, addr);
 205         off32 = off64;
 206         write32le(ptr, (read32le(ptr) & 0xfff)
 207                        | (((off32 >> 12) &  0xff) << 12)
 208                        | (((off32 >> 11) &     1) << 20)
 209                        | (((off32 >>  1) & 0x3ff) << 21)
 210                        | (((off32 >> 20) &     1) << 31));
 211         return;
 212     case R_RISCV_CALL:
 213     case R_RISCV_CALL_PLT:
 214         write32le(ptr, (read32le(ptr) & 0xfff)
 215                        | ((val - addr + 0x800) & ~0xfff));
 216         write32le(ptr + 4, (read32le(ptr + 4) & 0xfffff)
 217                            | (((val - addr) & 0xfff) << 20));
 218         return;
 219     case R_RISCV_PCREL_HI20:
 220 #ifdef DEBUG_RELOC
 221         printf("PCREL_HI20: val=%lx addr=%lx\n", val, addr);
 222 #endif
 223         off64 = (int64_t)(val - addr + 0x800) >> 12;
 224         if ((off64 + ((uint64_t)1 << 20)) >> 21)
 225           tcc_error("R_RISCV_PCREL_HI20 relocation failed: off=%lx cond=%lx sym=%s",
 226                     off64, ((int64_t)(off64 + ((uint64_t)1 << 20)) >> 21),
 227                     symtab_section->link->data + sym->st_name);
 228         write32le(ptr, (read32le(ptr) & 0xfff)
 229                        | ((off64 & 0xfffff) << 12));
 230         last_hi.addr = addr;
 231         last_hi.val = val;
 232         return;
 233     case R_RISCV_GOT_HI20:
 234         val = s1->got->sh_addr + get_sym_attr(s1, sym_index, 0)->got_offset;
 235         off64 = (int64_t)(val - addr + 0x800) >> 12;
 236         if ((off64 + ((uint64_t)1 << 20)) >> 21)
 237           tcc_error("R_RISCV_GOT_HI20 relocation failed");
 238         last_hi.addr = addr;
 239         last_hi.val = val;
 240         write32le(ptr, (read32le(ptr) & 0xfff)
 241                        | ((off64 & 0xfffff) << 12));
 242         return;
 243     case R_RISCV_PCREL_LO12_I:
 244 #ifdef DEBUG_RELOC
 245         printf("PCREL_LO12_I: val=%lx addr=%lx\n", val, addr);
 246 #endif
 247         if (val != last_hi.addr)
 248           tcc_error("unsupported hi/lo pcrel reloc scheme");
 249         val = last_hi.val;
 250         addr = last_hi.addr;
 251         write32le(ptr, (read32le(ptr) & 0xfffff)
 252                        | (((val - addr) & 0xfff) << 20));
 253         return;
 254     case R_RISCV_PCREL_LO12_S:
 255         if (val != last_hi.addr)
 256           tcc_error("unsupported hi/lo pcrel reloc scheme");
 257         val = last_hi.val;
 258         addr = last_hi.addr;
 259         off32 = val - addr;
 260         write32le(ptr, (read32le(ptr) & ~0xfe000f80)
 261                        | ((off32 & 0xfe0) << 20)
 262                        | ((off32 & 0x01f) << 7));
 263         return;
 264
 265     case R_RISCV_RVC_BRANCH:
 266         off64 = (val - addr);
 267         if ((off64 + (1 << 8)) & ~(uint64_t)0x1fe)
 268           tcc_error("R_RISCV_RVC_BRANCH relocation failed"
 269                     " (val=%lx, addr=%lx)", val, addr);
 270         off32 = off64;
 271         write16le(ptr, (read16le(ptr) & 0xe383)
 272                        | (((off32 >> 5) & 1) << 2)
 273                        | (((off32 >> 1) & 3) << 3)
 274                        | (((off32 >> 6) & 3) << 5)
 275                        | (((off32 >> 3) & 3) << 10)
 276                        | (((off32 >> 8) & 1) << 12));
 277         return;
 278     case R_RISCV_RVC_JUMP:
 279         off64 = (val - addr);
 280         if ((off64 + (1 << 11)) & ~(uint64_t)0xffe)
 281           tcc_error("R_RISCV_RVC_BRANCH relocation failed"
 282                     " (val=%lx, addr=%lx)", val, addr);
 283         off32 = off64;
 284         write16le(ptr, (read16le(ptr) & 0xe003)
 285                        | (((off32 >>  5) & 1) << 2)
 286                        | (((off32 >>  1) & 7) << 3)
 287                        | (((off32 >>  7) & 1) << 6)
 288                        | (((off32 >>  6) & 1) << 7)
 289                        | (((off32 >> 10) & 1) << 8)
 290                        | (((off32 >>  8) & 3) << 9)
 291                        | (((off32 >>  4) & 1) << 11)
 292                        | (((off32 >> 11) & 1) << 12));
 293         return;
 294
 295     case R_RISCV_32:
 296         write32le(ptr, val);
 297         return;
 298     case R_RISCV_JUMP_SLOT:
 299     case R_RISCV_64:
 300         write64le(ptr, val);
 301         return;
 302     case R_RISCV_ADD64:
 303         write64le(ptr, read64le(ptr) + val);
 304         return;
 305     case R_RISCV_ADD32:
 306         write32le(ptr, read32le(ptr) + val);
 307         return;
 308     case R_RISCV_SUB64:
 309         write64le(ptr, read64le(ptr) - val);
 310         return;
 311     case R_RISCV_SUB32:
 312         write32le(ptr, read32le(ptr) - val);
 313         return;
 314     case R_RISCV_ADD16:
 315         write16le(ptr, read16le(ptr) + val);
 316         return;
 317     case R_RISCV_SUB16:
 318         write16le(ptr, read16le(ptr) - val);
 319         return;
 320     case R_RISCV_SET6:
 321         *ptr = (*ptr & ~0x3f) | (val & 0x3f);
 322         return;
 323     case R_RISCV_SUB6:
 324         *ptr = (*ptr & ~0x3f) | ((*ptr - val) & 0x3f);
 325         return;
 326
 327     case R_RISCV_32_PCREL:
 328     case R_RISCV_COPY:
 329         /* XXX */
 330         return;
 331
 332     default:
 333         fprintf(stderr, "FIXME: handle reloc type %x at %x [%p] to %x\n",
 334                 type, (unsigned)addr, ptr, (unsigned)val);
 335         return;
 336     }
 337 }
 338 #endif