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 static const char *riscv_machine_arch(struct proc *p); 62 63 u_long elf_hwcap; 64 65 struct sysentvec elf64_freebsd_sysvec = { 66 .sv_size = SYS_MAXSYSCALL, 67 .sv_table = sysent, 68 .sv_errsize = 0, 69 .sv_errtbl = NULL, 70 .sv_transtrap = NULL, 71 .sv_fixup = __elfN(freebsd_fixup), 72 .sv_sendsig = sendsig, 73 .sv_sigcode = sigcode, 74 .sv_szsigcode = &szsigcode, 75 .sv_name = "FreeBSD ELF64", 76 .sv_coredump = __elfN(coredump), 77 .sv_imgact_try = NULL, 78 .sv_minsigstksz = MINSIGSTKSZ, 79 .sv_minuser = VM_MIN_ADDRESS, 80 .sv_maxuser = VM_MAXUSER_ADDRESS, 81 .sv_usrstack = USRSTACK, 82 .sv_psstrings = PS_STRINGS, 83 .sv_stackprot = VM_PROT_READ | VM_PROT_WRITE, 84 .sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs), 85 .sv_copyout_strings = exec_copyout_strings, 86 .sv_setregs = exec_setregs, 87 .sv_fixlimit = NULL, 88 .sv_maxssiz = NULL, 89 .sv_flags = SV_ABI_FREEBSD | SV_LP64 | SV_SHP | SV_ASLR, 90 .sv_set_syscall_retval = cpu_set_syscall_retval, 91 .sv_fetch_syscall_args = cpu_fetch_syscall_args, 92 .sv_syscallnames = syscallnames, 93 .sv_shared_page_base = SHAREDPAGE, 94 .sv_shared_page_len = PAGE_SIZE, 95 .sv_schedtail = NULL, 96 .sv_thread_detach = NULL, 97 .sv_trap = NULL, 98 .sv_hwcap = &elf_hwcap, 99 .sv_machine_arch = riscv_machine_arch, 100 }; 101 INIT_SYSENTVEC(elf64_sysvec, &elf64_freebsd_sysvec); 102 103 static const char * 104 riscv_machine_arch(struct proc *p) 105 { 106 107 if ((p->p_elf_flags & EF_RISCV_FLOAT_ABI_MASK) == 108 EF_RISCV_FLOAT_ABI_SOFT) 109 return (MACHINE_ARCH "sf"); 110 return (MACHINE_ARCH); 111 } 112 113 static Elf64_Brandinfo freebsd_brand_info = { 114 .brand = ELFOSABI_FREEBSD, 115 .machine = EM_RISCV, 116 .compat_3_brand = "FreeBSD", 117 .emul_path = NULL, 118 .interp_path = "/libexec/ld-elf.so.1", 119 .sysvec = &elf64_freebsd_sysvec, 120 .interp_newpath = NULL, 121 .brand_note = &elf64_freebsd_brandnote, 122 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE 123 }; 124 125 SYSINIT(elf64, SI_SUB_EXEC, SI_ORDER_FIRST, 126 (sysinit_cfunc_t)elf64_insert_brand_entry, &freebsd_brand_info); 127 128 static bool debug_kld; 129 SYSCTL_BOOL(_debug, OID_AUTO, kld_reloc, CTLFLAG_RW, &debug_kld, 0, 130 "Activate debug prints in elf_reloc_internal()"); 131 132 struct type2str_ent { 133 int type; 134 const char *str; 135 }; 136 137 void 138 elf64_dump_thread(struct thread *td, void *dst, size_t *off) 139 { 140 141 } 142 143 /* 144 * Following 4 functions are used to manupilate bits on 32bit interger value. 145 * FIXME: I implemetend for ease-to-understand rather than for well-optimized. 146 */ 147 static uint32_t 148 gen_bitmask(int msb, int lsb) 149 { 150 uint32_t mask; 151 152 if (msb == sizeof(mask) * 8 - 1) 153 mask = ~0; 154 else 155 mask = (1U << (msb + 1)) - 1; 156 157 if (lsb > 0) 158 mask &= ~((1U << lsb) - 1); 159 160 return (mask); 161 } 162 163 static uint32_t 164 extract_bits(uint32_t x, int msb, int lsb) 165 { 166 uint32_t mask; 167 168 mask = gen_bitmask(msb, lsb); 169 170 x &= mask; 171 x >>= lsb; 172 173 return (x); 174 } 175 176 static uint32_t 177 insert_bits(uint32_t d, uint32_t s, int msb, int lsb) 178 { 179 uint32_t mask; 180 181 mask = gen_bitmask(msb, lsb); 182 183 d &= ~mask; 184 185 s <<= lsb; 186 s &= mask; 187 188 return (d | s); 189 } 190 191 static uint32_t 192 insert_imm(uint32_t insn, uint32_t imm, int imm_msb, int imm_lsb, 193 int insn_lsb) 194 { 195 int insn_msb; 196 uint32_t v; 197 198 v = extract_bits(imm, imm_msb, imm_lsb); 199 insn_msb = (imm_msb - imm_lsb) + insn_lsb; 200 201 return (insert_bits(insn, v, insn_msb, insn_lsb)); 202 } 203 204 /* 205 * The RISC-V ISA is designed so that all of immediate values are 206 * sign-extended. 207 * An immediate value is sometimes generated at runtime by adding 208 * 12bit sign integer and 20bit signed integer. This requests 20bit 209 * immediate value to be ajusted if the MSB of the 12bit immediate 210 * value is asserted (sign-extended value is treated as negative value). 211 * 212 * For example, 0x123800 can be calculated by adding upper 20 bit of 213 * 0x124000 and sign-extended 12bit immediate whose bit pattern is 214 * 0x800 as follows: 215 * 0x123800 216 * = 0x123000 + 0x800 217 * = (0x123000 + 0x1000) + (-0x1000 + 0x800) 218 * = (0x123000 + 0x1000) + (0xff...ff800) 219 * = 0x124000 + sign-extention(0x800) 220 */ 221 static uint32_t 222 calc_hi20_imm(uint32_t value) 223 { 224 /* 225 * There is the arithmetical hack that can remove conditional 226 * statement. But I implement it in straightforward way. 227 */ 228 if ((value & 0x800) != 0) 229 value += 0x1000; 230 return (value & ~0xfff); 231 } 232 233 static const struct type2str_ent t2s[] = { 234 { R_RISCV_NONE, "R_RISCV_NONE" }, 235 { R_RISCV_64, "R_RISCV_64" }, 236 { R_RISCV_JUMP_SLOT, "R_RISCV_JUMP_SLOT" }, 237 { R_RISCV_RELATIVE, "R_RISCV_RELATIVE" }, 238 { R_RISCV_JAL, "R_RISCV_JAL" }, 239 { R_RISCV_CALL, "R_RISCV_CALL" }, 240 { R_RISCV_PCREL_HI20, "R_RISCV_PCREL_HI20" }, 241 { R_RISCV_PCREL_LO12_I, "R_RISCV_PCREL_LO12_I" }, 242 { R_RISCV_PCREL_LO12_S, "R_RISCV_PCREL_LO12_S" }, 243 { R_RISCV_HI20, "R_RISCV_HI20" }, 244 { R_RISCV_LO12_I, "R_RISCV_LO12_I" }, 245 { R_RISCV_LO12_S, "R_RISCV_LO12_S" }, 246 }; 247 248 static const char * 249 reloctype_to_str(int type) 250 { 251 int i; 252 253 for (i = 0; i < sizeof(t2s) / sizeof(t2s[0]); ++i) { 254 if (type == t2s[i].type) 255 return t2s[i].str; 256 } 257 258 return "*unknown*"; 259 } 260 261 bool 262 elf_is_ifunc_reloc(Elf_Size r_info __unused) 263 { 264 265 return (false); 266 } 267 268 /* 269 * Currently kernel loadable module for RISCV is compiled with -fPIC option. 270 * (see also additional CFLAGS definition for RISCV in sys/conf/kmod.mk) 271 * Only R_RISCV_64, R_RISCV_JUMP_SLOT and RISCV_RELATIVE are emitted in 272 * the module. Other relocations will be processed when kernel loadable 273 * modules are built in non-PIC. 274 * 275 * FIXME: only RISCV64 is supported. 276 */ 277 static int 278 elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data, 279 int type, int local, elf_lookup_fn lookup) 280 { 281 Elf_Size rtype, symidx; 282 const Elf_Rela *rela; 283 Elf_Addr val, addr; 284 Elf64_Addr *where; 285 Elf_Addr addend; 286 uint32_t before32_1; 287 uint32_t before32; 288 uint64_t before64; 289 uint32_t *insn32p; 290 uint32_t imm20; 291 int error; 292 293 switch (type) { 294 case ELF_RELOC_RELA: 295 rela = (const Elf_Rela *)data; 296 where = (Elf_Addr *)(relocbase + rela->r_offset); 297 insn32p = (uint32_t *)where; 298 addend = rela->r_addend; 299 rtype = ELF_R_TYPE(rela->r_info); 300 symidx = ELF_R_SYM(rela->r_info); 301 break; 302 default: 303 printf("%s:%d unknown reloc type %d\n", 304 __FUNCTION__, __LINE__, type); 305 return (-1); 306 } 307 308 switch (rtype) { 309 case R_RISCV_NONE: 310 break; 311 312 case R_RISCV_64: 313 case R_RISCV_JUMP_SLOT: 314 error = lookup(lf, symidx, 1, &addr); 315 if (error != 0) 316 return (-1); 317 318 val = addr; 319 before64 = *where; 320 if (*where != val) 321 *where = val; 322 if (debug_kld) 323 printf("%p %c %-24s %016lx -> %016lx\n", where, 324 (local ? 'l' : 'g'), reloctype_to_str(rtype), 325 before64, *where); 326 break; 327 328 case R_RISCV_RELATIVE: 329 before64 = *where; 330 *where = elf_relocaddr(lf, relocbase + addend); 331 if (debug_kld) 332 printf("%p %c %-24s %016lx -> %016lx\n", where, 333 (local ? 'l' : 'g'), reloctype_to_str(rtype), 334 before64, *where); 335 break; 336 337 case R_RISCV_JAL: 338 error = lookup(lf, symidx, 1, &addr); 339 if (error != 0) 340 return (-1); 341 342 val = addr - (Elf_Addr)where; 343 if (val <= -(1UL << 20) || (1UL << 20) <= val) { 344 printf("kldload: huge offset against R_RISCV_JAL\n"); 345 return (-1); 346 } 347 348 before32 = *insn32p; 349 *insn32p = insert_imm(*insn32p, val, 20, 20, 31); 350 *insn32p = insert_imm(*insn32p, val, 10, 1, 21); 351 *insn32p = insert_imm(*insn32p, val, 11, 11, 20); 352 *insn32p = insert_imm(*insn32p, val, 19, 12, 12); 353 if (debug_kld) 354 printf("%p %c %-24s %08x -> %08x\n", where, 355 (local ? 'l' : 'g'), reloctype_to_str(rtype), 356 before32, *insn32p); 357 break; 358 359 case R_RISCV_CALL: 360 /* 361 * R_RISCV_CALL relocates 8-byte region that consists 362 * of the sequence of AUIPC and JALR. 363 */ 364 /* Calculate and check the pc relative offset. */ 365 error = lookup(lf, symidx, 1, &addr); 366 if (error != 0) 367 return (-1); 368 369 val = addr - (Elf_Addr)where; 370 if (val <= -(1UL << 32) || (1UL << 32) <= val) { 371 printf("kldload: huge offset against R_RISCV_CALL\n"); 372 return (-1); 373 } 374 375 /* Relocate AUIPC. */ 376 before32 = insn32p[0]; 377 imm20 = calc_hi20_imm(val); 378 insn32p[0] = insert_imm(insn32p[0], imm20, 31, 12, 12); 379 380 /* Relocate JALR. */ 381 before32_1 = insn32p[1]; 382 insn32p[1] = insert_imm(insn32p[1], val, 11, 0, 20); 383 if (debug_kld) 384 printf("%p %c %-24s %08x %08x -> %08x %08x\n", where, 385 (local ? 'l' : 'g'), reloctype_to_str(rtype), 386 before32, insn32p[0], before32_1, insn32p[1]); 387 break; 388 389 case R_RISCV_PCREL_HI20: 390 error = lookup(lf, symidx, 1, &addr); 391 if (error != 0) 392 return (-1); 393 394 val = addr - (Elf_Addr)where; 395 insn32p = (uint32_t *)where; 396 before32 = *insn32p; 397 imm20 = calc_hi20_imm(val); 398 *insn32p = insert_imm(*insn32p, imm20, 31, 12, 12); 399 if (debug_kld) 400 printf("%p %c %-24s %08x -> %08x\n", where, 401 (local ? 'l' : 'g'), reloctype_to_str(rtype), 402 before32, *insn32p); 403 break; 404 405 case R_RISCV_PCREL_LO12_I: 406 error = lookup(lf, symidx, 1, &addr); 407 if (error != 0) 408 return (-1); 409 410 val = addr - (Elf_Addr)where; 411 insn32p = (uint32_t *)where; 412 before32 = *insn32p; 413 *insn32p = insert_imm(*insn32p, addr, 11, 0, 20); 414 if (debug_kld) 415 printf("%p %c %-24s %08x -> %08x\n", where, 416 (local ? 'l' : 'g'), reloctype_to_str(rtype), 417 before32, *insn32p); 418 break; 419 420 case R_RISCV_PCREL_LO12_S: 421 error = lookup(lf, symidx, 1, &addr); 422 if (error != 0) 423 return (-1); 424 425 val = addr - (Elf_Addr)where; 426 insn32p = (uint32_t *)where; 427 before32 = *insn32p; 428 *insn32p = insert_imm(*insn32p, addr, 11, 5, 25); 429 *insn32p = insert_imm(*insn32p, addr, 4, 0, 7); 430 if (debug_kld) 431 printf("%p %c %-24s %08x -> %08x\n", where, 432 (local ? 'l' : 'g'), reloctype_to_str(rtype), 433 before32, *insn32p); 434 break; 435 436 case R_RISCV_HI20: 437 error = lookup(lf, symidx, 1, &addr); 438 if (error != 0) 439 return (-1); 440 441 val = addr; 442 insn32p = (uint32_t *)where; 443 before32 = *insn32p; 444 imm20 = calc_hi20_imm(val); 445 *insn32p = insert_imm(*insn32p, imm20, 31, 12, 12); 446 if (debug_kld) 447 printf("%p %c %-24s %08x -> %08x\n", where, 448 (local ? 'l' : 'g'), reloctype_to_str(rtype), 449 before32, *insn32p); 450 break; 451 452 case R_RISCV_LO12_I: 453 error = lookup(lf, symidx, 1, &addr); 454 if (error != 0) 455 return (-1); 456 457 val = addr; 458 insn32p = (uint32_t *)where; 459 before32 = *insn32p; 460 *insn32p = insert_imm(*insn32p, addr, 11, 0, 20); 461 if (debug_kld) 462 printf("%p %c %-24s %08x -> %08x\n", where, 463 (local ? 'l' : 'g'), reloctype_to_str(rtype), 464 before32, *insn32p); 465 break; 466 467 case R_RISCV_LO12_S: 468 error = lookup(lf, symidx, 1, &addr); 469 if (error != 0) 470 return (-1); 471 472 val = addr; 473 insn32p = (uint32_t *)where; 474 before32 = *insn32p; 475 *insn32p = insert_imm(*insn32p, addr, 11, 5, 25); 476 *insn32p = insert_imm(*insn32p, addr, 4, 0, 7); 477 if (debug_kld) 478 printf("%p %c %-24s %08x -> %08x\n", where, 479 (local ? 'l' : 'g'), reloctype_to_str(rtype), 480 before32, *insn32p); 481 break; 482 483 default: 484 printf("kldload: unexpected relocation type %ld\n", rtype); 485 return (-1); 486 } 487 488 return (0); 489 } 490 491 int 492 elf_reloc(linker_file_t lf, Elf_Addr relocbase, const void *data, int type, 493 elf_lookup_fn lookup) 494 { 495 496 return (elf_reloc_internal(lf, relocbase, data, type, 0, lookup)); 497 } 498 499 int 500 elf_reloc_local(linker_file_t lf, Elf_Addr relocbase, const void *data, 501 int type, elf_lookup_fn lookup) 502 { 503 504 return (elf_reloc_internal(lf, relocbase, data, type, 1, lookup)); 505 } 506 507 int 508 elf_cpu_load_file(linker_file_t lf __unused) 509 { 510 511 return (0); 512 } 513 514 int 515 elf_cpu_unload_file(linker_file_t lf __unused) 516 { 517 518 return (0); 519 } 520 521 int 522 elf_cpu_parse_dynamic(caddr_t loadbase __unused, Elf_Dyn *dynamic __unused) 523 { 524 525 return (0); 526 } 527