1 /*- 2 * Copyright 1996-1998 John D. Polstra. 3 * Copyright (c) 2015 Ruslan Bukin <br@bsdpad.com> 4 * Copyright (c) 2016 Yukishige Shibata <y-shibat@mtd.biglobe.ne.jp> 5 * All rights reserved. 6 * 7 * Portions of this software were developed by SRI International and the 8 * University of Cambridge Computer Laboratory under DARPA/AFRL contract 9 * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme. 10 * 11 * Portions of this software were developed by the University of Cambridge 12 * Computer Laboratory as part of the CTSRD Project, with support from the 13 * UK Higher Education Innovation Fund (HEIF). 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #include <sys/cdefs.h> 38 __FBSDID("$FreeBSD$"); 39 40 #include <sys/param.h> 41 #include <sys/kernel.h> 42 #include <sys/systm.h> 43 #include <sys/exec.h> 44 #include <sys/imgact.h> 45 #include <sys/linker.h> 46 #include <sys/proc.h> 47 #include <sys/sysctl.h> 48 #include <sys/sysent.h> 49 #include <sys/imgact_elf.h> 50 #include <sys/syscall.h> 51 #include <sys/signalvar.h> 52 #include <sys/vnode.h> 53 54 #include <vm/vm.h> 55 #include <vm/pmap.h> 56 #include <vm/vm_param.h> 57 58 #include <machine/elf.h> 59 #include <machine/md_var.h> 60 61 u_long elf_hwcap; 62 63 struct sysentvec elf64_freebsd_sysvec = { 64 .sv_size = SYS_MAXSYSCALL, 65 .sv_table = sysent, 66 .sv_errsize = 0, 67 .sv_errtbl = NULL, 68 .sv_transtrap = NULL, 69 .sv_fixup = __elfN(freebsd_fixup), 70 .sv_sendsig = sendsig, 71 .sv_sigcode = sigcode, 72 .sv_szsigcode = &szsigcode, 73 .sv_name = "FreeBSD ELF64", 74 .sv_coredump = __elfN(coredump), 75 .sv_imgact_try = NULL, 76 .sv_minsigstksz = MINSIGSTKSZ, 77 .sv_minuser = VM_MIN_ADDRESS, 78 .sv_maxuser = VM_MAXUSER_ADDRESS, 79 .sv_usrstack = USRSTACK, 80 .sv_psstrings = PS_STRINGS, 81 .sv_stackprot = VM_PROT_READ | VM_PROT_WRITE, 82 .sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs), 83 .sv_copyout_strings = exec_copyout_strings, 84 .sv_setregs = exec_setregs, 85 .sv_fixlimit = NULL, 86 .sv_maxssiz = NULL, 87 .sv_flags = SV_ABI_FREEBSD | SV_LP64 | SV_SHP | SV_ASLR, 88 .sv_set_syscall_retval = cpu_set_syscall_retval, 89 .sv_fetch_syscall_args = cpu_fetch_syscall_args, 90 .sv_syscallnames = syscallnames, 91 .sv_shared_page_base = SHAREDPAGE, 92 .sv_shared_page_len = PAGE_SIZE, 93 .sv_schedtail = NULL, 94 .sv_thread_detach = NULL, 95 .sv_trap = NULL, 96 .sv_hwcap = &elf_hwcap, 97 }; 98 INIT_SYSENTVEC(elf64_sysvec, &elf64_freebsd_sysvec); 99 100 static Elf64_Brandinfo freebsd_brand_info = { 101 .brand = ELFOSABI_FREEBSD, 102 .machine = EM_RISCV, 103 .compat_3_brand = "FreeBSD", 104 .emul_path = NULL, 105 .interp_path = "/libexec/ld-elf.so.1", 106 .sysvec = &elf64_freebsd_sysvec, 107 .interp_newpath = NULL, 108 .brand_note = &elf64_freebsd_brandnote, 109 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE 110 }; 111 112 SYSINIT(elf64, SI_SUB_EXEC, SI_ORDER_FIRST, 113 (sysinit_cfunc_t)elf64_insert_brand_entry, &freebsd_brand_info); 114 115 static bool debug_kld; 116 SYSCTL_BOOL(_debug, OID_AUTO, kld_reloc, CTLFLAG_RW, &debug_kld, 0, 117 "Activate debug prints in elf_reloc_internal()"); 118 119 struct type2str_ent { 120 int type; 121 const char *str; 122 }; 123 124 void 125 elf64_dump_thread(struct thread *td, void *dst, size_t *off) 126 { 127 128 } 129 130 /* 131 * Following 4 functions are used to manupilate bits on 32bit interger value. 132 * FIXME: I implemetend for ease-to-understand rather than for well-optimized. 133 */ 134 static uint32_t 135 gen_bitmask(int msb, int lsb) 136 { 137 uint32_t mask; 138 139 if (msb == sizeof(mask) * 8 - 1) 140 mask = ~0; 141 else 142 mask = (1U << (msb + 1)) - 1; 143 144 if (lsb > 0) 145 mask &= ~((1U << lsb) - 1); 146 147 return (mask); 148 } 149 150 static uint32_t 151 extract_bits(uint32_t x, int msb, int lsb) 152 { 153 uint32_t mask; 154 155 mask = gen_bitmask(msb, lsb); 156 157 x &= mask; 158 x >>= lsb; 159 160 return (x); 161 } 162 163 static uint32_t 164 insert_bits(uint32_t d, uint32_t s, int msb, int lsb) 165 { 166 uint32_t mask; 167 168 mask = gen_bitmask(msb, lsb); 169 170 d &= ~mask; 171 172 s <<= lsb; 173 s &= mask; 174 175 return (d | s); 176 } 177 178 static uint32_t 179 insert_imm(uint32_t insn, uint32_t imm, int imm_msb, int imm_lsb, 180 int insn_lsb) 181 { 182 int insn_msb; 183 uint32_t v; 184 185 v = extract_bits(imm, imm_msb, imm_lsb); 186 insn_msb = (imm_msb - imm_lsb) + insn_lsb; 187 188 return (insert_bits(insn, v, insn_msb, insn_lsb)); 189 } 190 191 /* 192 * The RISC-V ISA is designed so that all of immediate values are 193 * sign-extended. 194 * An immediate value is sometimes generated at runtime by adding 195 * 12bit sign integer and 20bit signed integer. This requests 20bit 196 * immediate value to be ajusted if the MSB of the 12bit immediate 197 * value is asserted (sign-extended value is treated as negative value). 198 * 199 * For example, 0x123800 can be calculated by adding upper 20 bit of 200 * 0x124000 and sign-extended 12bit immediate whose bit pattern is 201 * 0x800 as follows: 202 * 0x123800 203 * = 0x123000 + 0x800 204 * = (0x123000 + 0x1000) + (-0x1000 + 0x800) 205 * = (0x123000 + 0x1000) + (0xff...ff800) 206 * = 0x124000 + sign-extention(0x800) 207 */ 208 static uint32_t 209 calc_hi20_imm(uint32_t value) 210 { 211 /* 212 * There is the arithmetical hack that can remove conditional 213 * statement. But I implement it in straightforward way. 214 */ 215 if ((value & 0x800) != 0) 216 value += 0x1000; 217 return (value & ~0xfff); 218 } 219 220 static const struct type2str_ent t2s[] = { 221 { R_RISCV_NONE, "R_RISCV_NONE" }, 222 { R_RISCV_64, "R_RISCV_64" }, 223 { R_RISCV_JUMP_SLOT, "R_RISCV_JUMP_SLOT" }, 224 { R_RISCV_RELATIVE, "R_RISCV_RELATIVE" }, 225 { R_RISCV_JAL, "R_RISCV_JAL" }, 226 { R_RISCV_CALL, "R_RISCV_CALL" }, 227 { R_RISCV_PCREL_HI20, "R_RISCV_PCREL_HI20" }, 228 { R_RISCV_PCREL_LO12_I, "R_RISCV_PCREL_LO12_I" }, 229 { R_RISCV_PCREL_LO12_S, "R_RISCV_PCREL_LO12_S" }, 230 { R_RISCV_HI20, "R_RISCV_HI20" }, 231 { R_RISCV_LO12_I, "R_RISCV_LO12_I" }, 232 { R_RISCV_LO12_S, "R_RISCV_LO12_S" }, 233 }; 234 235 static const char * 236 reloctype_to_str(int type) 237 { 238 int i; 239 240 for (i = 0; i < sizeof(t2s) / sizeof(t2s[0]); ++i) { 241 if (type == t2s[i].type) 242 return t2s[i].str; 243 } 244 245 return "*unknown*"; 246 } 247 248 bool 249 elf_is_ifunc_reloc(Elf_Size r_info __unused) 250 { 251 252 return (false); 253 } 254 255 /* 256 * Currently kernel loadable module for RISCV is compiled with -fPIC option. 257 * (see also additional CFLAGS definition for RISCV in sys/conf/kmod.mk) 258 * Only R_RISCV_64, R_RISCV_JUMP_SLOT and RISCV_RELATIVE are emitted in 259 * the module. Other relocations will be processed when kernel loadable 260 * modules are built in non-PIC. 261 * 262 * FIXME: only RISCV64 is supported. 263 */ 264 static int 265 elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data, 266 int type, int local, elf_lookup_fn lookup) 267 { 268 Elf_Size rtype, symidx; 269 const Elf_Rela *rela; 270 Elf_Addr val, addr; 271 Elf64_Addr *where; 272 Elf_Addr addend; 273 uint32_t before32_1; 274 uint32_t before32; 275 uint64_t before64; 276 uint32_t *insn32p; 277 uint32_t imm20; 278 int error; 279 280 switch (type) { 281 case ELF_RELOC_RELA: 282 rela = (const Elf_Rela *)data; 283 where = (Elf_Addr *)(relocbase + rela->r_offset); 284 insn32p = (uint32_t *)where; 285 addend = rela->r_addend; 286 rtype = ELF_R_TYPE(rela->r_info); 287 symidx = ELF_R_SYM(rela->r_info); 288 break; 289 default: 290 printf("%s:%d unknown reloc type %d\n", 291 __FUNCTION__, __LINE__, type); 292 return (-1); 293 } 294 295 switch (rtype) { 296 case R_RISCV_NONE: 297 break; 298 299 case R_RISCV_64: 300 case R_RISCV_JUMP_SLOT: 301 error = lookup(lf, symidx, 1, &addr); 302 if (error != 0) 303 return (-1); 304 305 val = addr; 306 before64 = *where; 307 if (*where != val) 308 *where = val; 309 if (debug_kld) 310 printf("%p %c %-24s %016lx -> %016lx\n", where, 311 (local ? 'l' : 'g'), reloctype_to_str(rtype), 312 before64, *where); 313 break; 314 315 case R_RISCV_RELATIVE: 316 before64 = *where; 317 *where = elf_relocaddr(lf, relocbase + addend); 318 if (debug_kld) 319 printf("%p %c %-24s %016lx -> %016lx\n", where, 320 (local ? 'l' : 'g'), reloctype_to_str(rtype), 321 before64, *where); 322 break; 323 324 case R_RISCV_JAL: 325 error = lookup(lf, symidx, 1, &addr); 326 if (error != 0) 327 return (-1); 328 329 val = addr - (Elf_Addr)where; 330 if (val <= -(1UL << 20) || (1UL << 20) <= val) { 331 printf("kldload: huge offset against R_RISCV_JAL\n"); 332 return (-1); 333 } 334 335 before32 = *insn32p; 336 *insn32p = insert_imm(*insn32p, val, 20, 20, 31); 337 *insn32p = insert_imm(*insn32p, val, 10, 1, 21); 338 *insn32p = insert_imm(*insn32p, val, 11, 11, 20); 339 *insn32p = insert_imm(*insn32p, val, 19, 12, 12); 340 if (debug_kld) 341 printf("%p %c %-24s %08x -> %08x\n", where, 342 (local ? 'l' : 'g'), reloctype_to_str(rtype), 343 before32, *insn32p); 344 break; 345 346 case R_RISCV_CALL: 347 /* 348 * R_RISCV_CALL relocates 8-byte region that consists 349 * of the sequence of AUIPC and JALR. 350 */ 351 /* Calculate and check the pc relative offset. */ 352 error = lookup(lf, symidx, 1, &addr); 353 if (error != 0) 354 return (-1); 355 356 val = addr - (Elf_Addr)where; 357 if (val <= -(1UL << 32) || (1UL << 32) <= val) { 358 printf("kldload: huge offset against R_RISCV_CALL\n"); 359 return (-1); 360 } 361 362 /* Relocate AUIPC. */ 363 before32 = insn32p[0]; 364 imm20 = calc_hi20_imm(val); 365 insn32p[0] = insert_imm(insn32p[0], imm20, 31, 12, 12); 366 367 /* Relocate JALR. */ 368 before32_1 = insn32p[1]; 369 insn32p[1] = insert_imm(insn32p[1], val, 11, 0, 20); 370 if (debug_kld) 371 printf("%p %c %-24s %08x %08x -> %08x %08x\n", where, 372 (local ? 'l' : 'g'), reloctype_to_str(rtype), 373 before32, insn32p[0], before32_1, insn32p[1]); 374 break; 375 376 case R_RISCV_PCREL_HI20: 377 error = lookup(lf, symidx, 1, &addr); 378 if (error != 0) 379 return (-1); 380 381 val = addr - (Elf_Addr)where; 382 insn32p = (uint32_t *)where; 383 before32 = *insn32p; 384 imm20 = calc_hi20_imm(val); 385 *insn32p = insert_imm(*insn32p, imm20, 31, 12, 12); 386 if (debug_kld) 387 printf("%p %c %-24s %08x -> %08x\n", where, 388 (local ? 'l' : 'g'), reloctype_to_str(rtype), 389 before32, *insn32p); 390 break; 391 392 case R_RISCV_PCREL_LO12_I: 393 error = lookup(lf, symidx, 1, &addr); 394 if (error != 0) 395 return (-1); 396 397 val = addr - (Elf_Addr)where; 398 insn32p = (uint32_t *)where; 399 before32 = *insn32p; 400 *insn32p = insert_imm(*insn32p, addr, 11, 0, 20); 401 if (debug_kld) 402 printf("%p %c %-24s %08x -> %08x\n", where, 403 (local ? 'l' : 'g'), reloctype_to_str(rtype), 404 before32, *insn32p); 405 break; 406 407 case R_RISCV_PCREL_LO12_S: 408 error = lookup(lf, symidx, 1, &addr); 409 if (error != 0) 410 return (-1); 411 412 val = addr - (Elf_Addr)where; 413 insn32p = (uint32_t *)where; 414 before32 = *insn32p; 415 *insn32p = insert_imm(*insn32p, addr, 11, 5, 25); 416 *insn32p = insert_imm(*insn32p, addr, 4, 0, 7); 417 if (debug_kld) 418 printf("%p %c %-24s %08x -> %08x\n", where, 419 (local ? 'l' : 'g'), reloctype_to_str(rtype), 420 before32, *insn32p); 421 break; 422 423 case R_RISCV_HI20: 424 error = lookup(lf, symidx, 1, &addr); 425 if (error != 0) 426 return (-1); 427 428 val = addr; 429 insn32p = (uint32_t *)where; 430 before32 = *insn32p; 431 imm20 = calc_hi20_imm(val); 432 *insn32p = insert_imm(*insn32p, imm20, 31, 12, 12); 433 if (debug_kld) 434 printf("%p %c %-24s %08x -> %08x\n", where, 435 (local ? 'l' : 'g'), reloctype_to_str(rtype), 436 before32, *insn32p); 437 break; 438 439 case R_RISCV_LO12_I: 440 error = lookup(lf, symidx, 1, &addr); 441 if (error != 0) 442 return (-1); 443 444 val = addr; 445 insn32p = (uint32_t *)where; 446 before32 = *insn32p; 447 *insn32p = insert_imm(*insn32p, addr, 11, 0, 20); 448 if (debug_kld) 449 printf("%p %c %-24s %08x -> %08x\n", where, 450 (local ? 'l' : 'g'), reloctype_to_str(rtype), 451 before32, *insn32p); 452 break; 453 454 case R_RISCV_LO12_S: 455 error = lookup(lf, symidx, 1, &addr); 456 if (error != 0) 457 return (-1); 458 459 val = addr; 460 insn32p = (uint32_t *)where; 461 before32 = *insn32p; 462 *insn32p = insert_imm(*insn32p, addr, 11, 5, 25); 463 *insn32p = insert_imm(*insn32p, addr, 4, 0, 7); 464 if (debug_kld) 465 printf("%p %c %-24s %08x -> %08x\n", where, 466 (local ? 'l' : 'g'), reloctype_to_str(rtype), 467 before32, *insn32p); 468 break; 469 470 default: 471 printf("kldload: unexpected relocation type %ld\n", rtype); 472 return (-1); 473 } 474 475 return (0); 476 } 477 478 int 479 elf_reloc(linker_file_t lf, Elf_Addr relocbase, const void *data, int type, 480 elf_lookup_fn lookup) 481 { 482 483 return (elf_reloc_internal(lf, relocbase, data, type, 0, lookup)); 484 } 485 486 int 487 elf_reloc_local(linker_file_t lf, Elf_Addr relocbase, const void *data, 488 int type, elf_lookup_fn lookup) 489 { 490 491 return (elf_reloc_internal(lf, relocbase, data, type, 1, lookup)); 492 } 493 494 int 495 elf_cpu_load_file(linker_file_t lf __unused) 496 { 497 498 return (0); 499 } 500 501 int 502 elf_cpu_unload_file(linker_file_t lf __unused) 503 { 504 505 return (0); 506 } 507 508 int 509 elf_cpu_parse_dynamic(linker_file_t lf __unused, Elf_Dyn *dynamic __unused) 510 { 511 512 return (0); 513 } 514