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