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