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 #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
  30     case R_RISCV_BRANCH:
  31     case R_RISCV_CALL:
  32     case R_RISCV_JAL:
  33         return 1;
  34
  35     case R_RISCV_GOT_HI20:
  36     case R_RISCV_PCREL_HI20:
  37     case R_RISCV_PCREL_LO12_I:
  38     case R_RISCV_PCREL_LO12_S:
  39     case R_RISCV_32_PCREL:
  40     case R_RISCV_ADD32:
  41     case R_RISCV_SUB32:
  42     case R_RISCV_32:
  43     case R_RISCV_64:
  44         return 0;
  45
  46     case R_RISCV_CALL_PLT:
  47         return 1;
  48     }
  49     tcc_error ("Unknown relocation type in code_reloc: %d", reloc_type);
  50     return -1;
  51 }
  52
  53 /* Returns an enumerator to describe whether and when the relocation needs a
  54    GOT and/or PLT entry to be created. See tcc.h for a description of the
  55    different values. */
  56 int gotplt_entry_type (int reloc_type)
  57 {
  58     switch (reloc_type) {
  59     case R_RISCV_ALIGN:
  60     case R_RISCV_RELAX:
  61     case R_RISCV_RVC_BRANCH:
  62     case R_RISCV_RVC_JUMP:
  63     case R_RISCV_JUMP_SLOT:
  64         return NO_GOTPLT_ENTRY;
  65
  66     case R_RISCV_BRANCH:
  67     case R_RISCV_CALL:
  68     case R_RISCV_PCREL_HI20:
  69     case R_RISCV_PCREL_LO12_I:
  70     case R_RISCV_PCREL_LO12_S:
  71     case R_RISCV_32_PCREL:
  72     case R_RISCV_ADD32:
  73     case R_RISCV_SUB32:
  74     case R_RISCV_32:
  75     case R_RISCV_64:
  76     case R_RISCV_JAL:
  77         return AUTO_GOTPLT_ENTRY;
  78
  79     case R_RISCV_GOT_HI20:
  80     case R_RISCV_CALL_PLT:
  81         return ALWAYS_GOTPLT_ENTRY;
  82     }
  83
  84     tcc_error ("Unknown relocation type: %d", reloc_type);
  85     return -1;
  86 }
  87
  88 ST_FUNC unsigned create_plt_entry(TCCState *s1, unsigned got_offset, struct sym_attr *attr)
  89 {
  90     Section *plt = s1->plt;
  91     uint8_t *p;
  92     unsigned plt_offset;
  93
  94     if (s1->output_type == TCC_OUTPUT_DLL)
  95         tcc_error("DLLs unimplemented!");
  96
  97     if (plt->data_offset == 0)
  98         section_ptr_add(plt, 32);
  99     plt_offset = plt->data_offset;
 100
 101     p = section_ptr_add(plt, 16);
 102     write64le(p, got_offset);
 103     return plt_offset;
 104 }
 105
 106 /* relocate the PLT: compute addresses and offsets in the PLT now that final
 107    address for PLT and GOT are known (see fill_program_header) */
 108 ST_FUNC void relocate_plt(TCCState *s1)
 109 {
 110     uint8_t *p, *p_end;
 111
 112     if (!s1->plt)
 113       return;
 114
 115     p = s1->plt->data;
 116     p_end = p + s1->plt->data_offset;
 117
 118     if (p < p_end) {
 119         uint64_t plt = s1->plt->sh_addr;
 120         uint64_t got = s1->got->sh_addr;
 121         uint64_t off = (got - plt + 0x800) >> 12;
 122         if ((off + ((uint32_t)1 << 20)) >> 21)
 123             tcc_error("Failed relocating PLT (off=0x%lx, got=0x%lx, plt=0x%lx)", off, got, plt);
 124         write32le(p, 0x397 | (off << 12)); // auipc t2, %pcrel_hi(got)
 125         write32le(p + 4, 0x41c30333); // sub t1, t1, t3
 126         write32le(p + 8, 0x0003be03   // ld t3, %pcrel_lo(got)(t2)
 127                          | (((got - plt) & 0xfff) << 20));
 128         write32le(p + 12, 0xfd430313); // addi t1, t1, -(32+12)
 129         write32le(p + 16, 0x00038293   // addi t0, t2, %pcrel_lo(got)
 130                           | (((got - plt) & 0xfff) << 20));
 131         write32le(p + 20, 0x00135313); // srli t1, t1, log2(16/PTRSIZE)
 132         write32le(p + 24, 0x0082b283); // ld t0, PTRSIZE(t0)
 133         write32le(p + 28, 0x000e0067); // jr t3
 134         p += 32;
 135         while (p < p_end) {
 136             uint64_t pc = plt + (p - s1->plt->data);
 137             uint64_t addr = got + read64le(p);
 138             uint64_t off = (addr - pc + 0x800) >> 12;
 139             if ((off + ((uint32_t)1 << 20)) >> 21)
 140                 tcc_error("Failed relocating PLT (off=0x%lx, addr=0x%lx, pc=0x%lx)", off, addr, pc);
 141             write32le(p, 0xe17 | (off << 12)); // auipc t3, %pcrel_hi(func@got)
 142             write32le(p + 4, 0x000e3e03 // ld t3, %pcrel_lo(func@got)(t3)
 143                              | (((addr - pc) & 0xfff) << 20));
 144             write32le(p + 8, 0x000e0367); // jalr t1, t3
 145             write32le(p + 12, 0x00000013); // nop
 146             p += 16;
 147         }
 148     }
 149 }
 150
 151 void relocate_init(Section *sr) {}
 152
 153 void relocate_fini(Section *sr)
 154 {
 155 }
 156
 157 struct pcrel_hi {
 158     addr_t addr, val;
 159 };
 160 static struct pcrel_hi last_hi;
 161
 162 void relocate(TCCState *s1, ElfW_Rel *rel, int type, unsigned char *ptr,
 163               addr_t addr, addr_t val)
 164 {
 165     uint64_t off64;
 166     uint32_t off32;
 167     int sym_index = ELFW(R_SYM)(rel->r_info);
 168 #ifdef DEBUG_RELOC
 169     ElfW(Sym) *sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
 170 #endif
 171
 172     switch(type) {
 173     case R_RISCV_ALIGN:
 174     case R_RISCV_RELAX:
 175         return;
 176
 177     case R_RISCV_BRANCH:
 178         off64 = val - addr;
 179         if ((off64 + (1 << 12)) & ~(uint64_t)0x1ffe)
 180           tcc_error("R_RISCV_BRANCH relocation failed"
 181                     " (val=%lx, addr=%lx)", val, addr);
 182         off32 = off64 >> 1;
 183         write32le(ptr, (read32le(ptr) & ~0xfe000f80)
 184                        | ((off32 & 0x800) << 20)
 185                        | ((off32 & 0x3f0) << 21)
 186                        | ((off32 & 0x00f) << 8)
 187                        | ((off32 & 0x400) >> 3));
 188         return;
 189     case R_RISCV_JAL:
 190         off64 = val - addr;
 191         if ((off64 + (1 << 21)) & ~(((uint64_t)1 << 22) - 2))
 192           tcc_error("R_RISCV_JAL relocation failed"
 193                     " (val=%lx, addr=%lx)", val, addr);
 194         off32 = off64;
 195         write32le(ptr, (read32le(ptr) & 0xfff)
 196                        | (((off32 >> 12) &  0xff) << 12)
 197                        | (((off32 >> 11) &     1) << 20)
 198                        | (((off32 >>  1) & 0x3ff) << 21)
 199                        | (((off32 >> 20) &     1) << 31));
 200         return;
 201     case R_RISCV_CALL:
 202     case R_RISCV_CALL_PLT:
 203         write32le(ptr, (read32le(ptr) & 0xfff)
 204                        | ((val - addr + 0x800) & ~0xfff));
 205         write32le(ptr + 4, (read32le(ptr + 4) & 0xfffff)
 206                            | (((val - addr) & 0xfff) << 20));
 207         return;
 208     case R_RISCV_PCREL_HI20:
 209 #ifdef DEBUG_RELOC
 210         printf("PCREL_HI20: val=%lx addr=%lx\n", val, addr);
 211 #endif
 212         off64 = (int64_t)(val - addr + 0x800) >> 12;
 213         if ((off64 + ((uint64_t)1 << 20)) >> 21)
 214           tcc_error("R_RISCV_PCREL_HI20 relocation failed: off=%lx cond=%lx",
 215                     off64, ((int64_t)(off64 + ((uint64_t)1 << 20)) >> 21));
 216         write32le(ptr, (read32le(ptr) & 0xfff)
 217                        | ((off64 & 0xfffff) << 12));
 218         last_hi.addr = addr;
 219         last_hi.val = val;
 220         return;
 221     case R_RISCV_GOT_HI20:
 222         val = s1->got->sh_addr + get_sym_attr(s1, sym_index, 0)->got_offset;
 223         off64 = (int64_t)(val - addr + 0x800) >> 12;
 224         if ((off64 + ((uint64_t)1 << 20)) >> 21)
 225           tcc_error("R_RISCV_GOT_HI20 relocation failed");
 226         last_hi.addr = addr;
 227         last_hi.val = val;
 228         write32le(ptr, (read32le(ptr) & 0xfff)
 229                        | ((off64 & 0xfffff) << 12));
 230         return;
 231     case R_RISCV_PCREL_LO12_I:
 232 #ifdef DEBUG_RELOC
 233         printf("PCREL_LO12_I: val=%lx addr=%lx\n", val, addr);
 234 #endif
 235         if (val != last_hi.addr)
 236           tcc_error("unsupported hi/lo pcrel reloc scheme");
 237         val = last_hi.val;
 238         addr = last_hi.addr;
 239         write32le(ptr, (read32le(ptr) & 0xfffff)
 240                        | (((val - addr) & 0xfff) << 20));
 241         return;
 242     case R_RISCV_PCREL_LO12_S:
 243         if (val != last_hi.addr)
 244           tcc_error("unsupported hi/lo pcrel reloc scheme");
 245         val = last_hi.val;
 246         addr = last_hi.addr;
 247         off32 = val - addr;
 248         write32le(ptr, (read32le(ptr) & ~0xfe000f80)
 249                        | ((off32 & 0xfe0) << 20)
 250                        | ((off32 & 0x01f) << 7));
 251         return;
 252
 253     case R_RISCV_RVC_BRANCH:
 254         off64 = (val - addr);
 255         if ((off64 + (1 << 8)) & ~(uint64_t)0x1fe)
 256           tcc_error("R_RISCV_RVC_BRANCH relocation failed"
 257                     " (val=%lx, addr=%lx)", val, addr);
 258         off32 = off64;
 259         write16le(ptr, (read16le(ptr) & 0xe383)
 260                        | (((off32 >> 5) & 1) << 2)
 261                        | (((off32 >> 1) & 3) << 3)
 262                        | (((off32 >> 6) & 3) << 5)
 263                        | (((off32 >> 3) & 3) << 10)
 264                        | (((off32 >> 8) & 1) << 12));
 265         return;
 266     case R_RISCV_RVC_JUMP:
 267         off64 = (val - addr);
 268         if ((off64 + (1 << 11)) & ~(uint64_t)0xffe)
 269           tcc_error("R_RISCV_RVC_BRANCH relocation failed"
 270                     " (val=%lx, addr=%lx)", val, addr);
 271         off32 = off64;
 272         write16le(ptr, (read16le(ptr) & 0xe003)
 273                        | (((off32 >>  5) & 1) << 2)
 274                        | (((off32 >>  1) & 7) << 3)
 275                        | (((off32 >>  7) & 1) << 6)
 276                        | (((off32 >>  6) & 1) << 7)
 277                        | (((off32 >> 10) & 1) << 8)
 278                        | (((off32 >>  8) & 3) << 9)
 279                        | (((off32 >>  4) & 1) << 11)
 280                        | (((off32 >> 11) & 1) << 12));
 281         return;
 282
 283     case R_RISCV_32:
 284         write32le(ptr, val);
 285         return;
 286     case R_RISCV_JUMP_SLOT:
 287     case R_RISCV_64:
 288         write64le(ptr, val);
 289         return;
 290     case R_RISCV_ADD32:
 291         write32le(ptr, read32le(ptr) + val);
 292         return;
 293     case R_RISCV_SUB32:
 294         write32le(ptr, read32le(ptr) - val);
 295         return;
 296
 297     case R_RISCV_32_PCREL:
 298     case R_RISCV_COPY:
 299         /* XXX */
 300         return;
 301
 302     default:
 303         fprintf(stderr, "FIXME: handle reloc type %x at %x [%p] to %x\n",
 304                 type, (unsigned)addr, ptr, (unsigned)val);
 305         return;
 306     }
 307 }
 308 #endif