1 /*-
2 * Copyright 1996-1998 John D. Polstra.
3 * Copyright (c) 2015 Ruslan Bukin <[email protected]>
4 * Copyright (c) 2016 Yukishige Shibata <[email protected]>
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_mask = 0,
67 .sv_errsize = 0,
68 .sv_errtbl = NULL,
69 .sv_transtrap = NULL,
70 .sv_fixup = __elfN(freebsd_fixup),
71 .sv_sendsig = sendsig,
72 .sv_sigcode = sigcode,
73 .sv_szsigcode = &szsigcode,
74 .sv_name = "FreeBSD ELF64",
75 .sv_coredump = __elfN(coredump),
76 .sv_imgact_try = NULL,
77 .sv_minsigstksz = MINSIGSTKSZ,
78 .sv_minuser = VM_MIN_ADDRESS,
79 .sv_maxuser = VM_MAXUSER_ADDRESS,
80 .sv_usrstack = USRSTACK,
81 .sv_psstrings = PS_STRINGS,
82 .sv_stackprot = VM_PROT_ALL,
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_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_schedtail = NULL,
92 .sv_thread_detach = NULL,
93 .sv_trap = NULL,
94 .sv_hwcap = &elf_hwcap,
95 };
96 INIT_SYSENTVEC(elf64_sysvec, &elf64_freebsd_sysvec);
97
98 static Elf64_Brandinfo freebsd_brand_info = {
99 .brand = ELFOSABI_FREEBSD,
100 .machine = EM_RISCV,
101 .compat_3_brand = "FreeBSD",
102 .emul_path = NULL,
103 .interp_path = "/libexec/ld-elf.so.1",
104 .sysvec = &elf64_freebsd_sysvec,
105 .interp_newpath = NULL,
106 .brand_note = &elf64_freebsd_brandnote,
107 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
108 };
109
110 SYSINIT(elf64, SI_SUB_EXEC, SI_ORDER_FIRST,
111 (sysinit_cfunc_t) elf64_insert_brand_entry,
112 &freebsd_brand_info);
113
114 static Elf64_Brandinfo freebsd_brand_oinfo = {
115 .brand = ELFOSABI_FREEBSD,
116 .machine = EM_RISCV,
117 .compat_3_brand = "FreeBSD",
118 .emul_path = NULL,
119 .interp_path = "/usr/libexec/ld-elf.so.1",
120 .sysvec = &elf64_freebsd_sysvec,
121 .interp_newpath = NULL,
122 .brand_note = &elf64_freebsd_brandnote,
123 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
124 };
125
126 SYSINIT(oelf64, SI_SUB_EXEC, SI_ORDER_ANY,
127 (sysinit_cfunc_t) elf64_insert_brand_entry,
128 &freebsd_brand_oinfo);
129
130 static int debug_kld;
131 SYSCTL_INT(_kern, OID_AUTO, debug_kld,
132 CTLFLAG_RW, &debug_kld, 0,
133 "Activate debug prints in elf_reloc_internal()");
134
135 struct type2str_ent {
136 int type;
137 const char *str;
138 };
139
140 void
elf64_dump_thread(struct thread * td,void * dst,size_t * off)141 elf64_dump_thread(struct thread *td, void *dst, size_t *off)
142 {
143
144 }
145
146 /*
147 * Following 4 functions are used to manupilate bits on 32bit interger value.
148 * FIXME: I implemetend for ease-to-understand rather than for well-optimized.
149 */
150 static uint32_t
gen_bitmask(int msb,int lsb)151 gen_bitmask(int msb, int lsb)
152 {
153 uint32_t mask;
154
155 if (msb == sizeof(mask) * 8 - 1)
156 mask = ~0;
157 else
158 mask = (1U << (msb + 1)) - 1;
159
160 if (lsb > 0)
161 mask &= ~((1U << lsb) - 1);
162
163 return (mask);
164 }
165
166 static uint32_t
extract_bits(uint32_t x,int msb,int lsb)167 extract_bits(uint32_t x, int msb, int lsb)
168 {
169 uint32_t mask;
170
171 mask = gen_bitmask(msb, lsb);
172
173 x &= mask;
174 x >>= lsb;
175
176 return (x);
177 }
178
179 static uint32_t
insert_bits(uint32_t d,uint32_t s,int msb,int lsb)180 insert_bits(uint32_t d, uint32_t s, int msb, int lsb)
181 {
182 uint32_t mask;
183
184 mask = gen_bitmask(msb, lsb);
185
186 d &= ~mask;
187
188 s <<= lsb;
189 s &= mask;
190
191 return (d | s);
192 }
193
194 static uint32_t
insert_imm(uint32_t insn,uint32_t imm,int imm_msb,int imm_lsb,int insn_lsb)195 insert_imm(uint32_t insn, uint32_t imm, int imm_msb, int imm_lsb,
196 int insn_lsb)
197 {
198 int insn_msb;
199 uint32_t v;
200
201 v = extract_bits(imm, imm_msb, imm_lsb);
202 insn_msb = (imm_msb - imm_lsb) + insn_lsb;
203
204 return (insert_bits(insn, v, insn_msb, insn_lsb));
205 }
206
207 /*
208 * The RISC-V ISA is designed so that all of immediate values are
209 * sign-extended.
210 * An immediate value is sometimes generated at runtime by adding
211 * 12bit sign integer and 20bit signed integer. This requests 20bit
212 * immediate value to be ajusted if the MSB of the 12bit immediate
213 * value is asserted (sign-extended value is treated as negative value).
214 *
215 * For example, 0x123800 can be calculated by adding upper 20 bit of
216 * 0x124000 and sign-extended 12bit immediate whose bit pattern is
217 * 0x800 as follows:
218 * 0x123800
219 * = 0x123000 + 0x800
220 * = (0x123000 + 0x1000) + (-0x1000 + 0x800)
221 * = (0x123000 + 0x1000) + (0xff...ff800)
222 * = 0x124000 + sign-extention(0x800)
223 */
224 static uint32_t
calc_hi20_imm(uint32_t value)225 calc_hi20_imm(uint32_t value)
226 {
227 /*
228 * There is the arithmetical hack that can remove conditional
229 * statement. But I implement it in straightforward way.
230 */
231 if ((value & 0x800) != 0)
232 value += 0x1000;
233 return (value & ~0xfff);
234 }
235
236 static const struct type2str_ent t2s[] = {
237 { R_RISCV_NONE, "R_RISCV_NONE" },
238 { R_RISCV_64, "R_RISCV_64" },
239 { R_RISCV_JUMP_SLOT, "R_RISCV_JUMP_SLOT" },
240 { R_RISCV_RELATIVE, "R_RISCV_RELATIVE" },
241 { R_RISCV_JAL, "R_RISCV_JAL" },
242 { R_RISCV_CALL, "R_RISCV_CALL" },
243 { R_RISCV_PCREL_HI20, "R_RISCV_PCREL_HI20" },
244 { R_RISCV_PCREL_LO12_I, "R_RISCV_PCREL_LO12_I" },
245 { R_RISCV_PCREL_LO12_S, "R_RISCV_PCREL_LO12_S" },
246 { R_RISCV_HI20, "R_RISCV_HI20" },
247 { R_RISCV_LO12_I, "R_RISCV_LO12_I" },
248 { R_RISCV_LO12_S, "R_RISCV_LO12_S" },
249 };
250
251 static const char *
reloctype_to_str(int type)252 reloctype_to_str(int type)
253 {
254 int i;
255
256 for (i = 0; i < sizeof(t2s) / sizeof(t2s[0]); ++i) {
257 if (type == t2s[i].type)
258 return t2s[i].str;
259 }
260
261 return "*unknown*";
262 }
263
264 bool
elf_is_ifunc_reloc(Elf_Size r_info __unused)265 elf_is_ifunc_reloc(Elf_Size r_info __unused)
266 {
267
268 return (false);
269 }
270
271 /*
272 * Currently kernel loadable module for RISCV is compiled with -fPIC option.
273 * (see also additional CFLAGS definition for RISCV in sys/conf/kmod.mk)
274 * Only R_RISCV_64, R_RISCV_JUMP_SLOT and RISCV_RELATIVE are emitted in
275 * the module. Other relocations will be processed when kernel loadable
276 * modules are built in non-PIC.
277 *
278 * FIXME: only RISCV64 is supported.
279 */
280 static int
elf_reloc_internal(linker_file_t lf,Elf_Addr relocbase,const void * data,int type,int local,elf_lookup_fn lookup)281 elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
282 int type, int local, elf_lookup_fn lookup)
283 {
284 Elf_Size rtype, symidx;
285 const Elf_Rela *rela;
286 Elf_Addr val, addr;
287 Elf64_Addr *where;
288 Elf_Addr addend;
289 uint32_t before32_1;
290 uint32_t before32;
291 uint64_t before64;
292 uint32_t* insn32p;
293 uint32_t imm20;
294 int error;
295
296 switch (type) {
297 case ELF_RELOC_RELA:
298 rela = (const Elf_Rela *)data;
299 where = (Elf_Addr *)(relocbase + rela->r_offset);
300 insn32p = (uint32_t*)where;
301 addend = rela->r_addend;
302 rtype = ELF_R_TYPE(rela->r_info);
303 symidx = ELF_R_SYM(rela->r_info);
304 break;
305 default:
306 printf("%s:%d unknown reloc type %d\n",
307 __FUNCTION__, __LINE__, type);
308 return -1;
309 }
310
311 switch (rtype) {
312 case R_RISCV_NONE:
313 break;
314
315 case R_RISCV_64:
316 case R_RISCV_JUMP_SLOT:
317 error = lookup(lf, symidx, 1, &addr);
318 if (error != 0)
319 return -1;
320
321 val = addr;
322 before64 = *where;
323 if (*where != val)
324 *where = val;
325
326 if (debug_kld)
327 printf("%p %c %-24s %016lx -> %016lx\n",
328 where,
329 (local? 'l': 'g'),
330 reloctype_to_str(rtype),
331 before64, *where);
332 break;
333
334 case R_RISCV_RELATIVE:
335 before64 = *where;
336
337 *where = elf_relocaddr(lf, relocbase + addend);
338
339 if (debug_kld)
340 printf("%p %c %-24s %016lx -> %016lx\n",
341 where,
342 (local? 'l': 'g'),
343 reloctype_to_str(rtype),
344 before64, *where);
345 break;
346
347 case R_RISCV_JAL:
348 error = lookup(lf, symidx, 1, &addr);
349 if (error != 0)
350 return -1;
351
352 val = addr - (Elf_Addr)where;
353 if ((val <= -(1UL << 20) || (1UL << 20) <= val)) {
354 printf("kldload: huge offset against R_RISCV_JAL\n");
355 return -1;
356 }
357
358 before32 = *insn32p;
359 *insn32p = insert_imm(*insn32p, val, 20, 20, 31);
360 *insn32p = insert_imm(*insn32p, val, 10, 1, 21);
361 *insn32p = insert_imm(*insn32p, val, 11, 11, 20);
362 *insn32p = insert_imm(*insn32p, val, 19, 12, 12);
363
364 if (debug_kld)
365 printf("%p %c %-24s %08x -> %08x\n",
366 where,
367 (local? 'l': 'g'),
368 reloctype_to_str(rtype),
369 before32, *insn32p);
370 break;
371
372 case R_RISCV_CALL:
373 /*
374 * R_RISCV_CALL relocates 8-byte region that consists
375 * of the sequence of AUIPC and JALR.
376 */
377 /* calculate and check the pc relative offset. */
378 error = lookup(lf, symidx, 1, &addr);
379 if (error != 0)
380 return -1;
381 val = addr - (Elf_Addr)where;
382 if ((val <= -(1UL << 32) || (1UL << 32) <= val)) {
383 printf("kldload: huge offset against R_RISCV_CALL\n");
384 return -1;
385 }
386
387 /* Relocate AUIPC. */
388 before32 = insn32p[0];
389 imm20 = calc_hi20_imm(val);
390 insn32p[0] = insert_imm(insn32p[0], imm20, 31, 12, 12);
391
392 /* Relocate JALR. */
393 before32_1 = insn32p[1];
394 insn32p[1] = insert_imm(insn32p[1], val, 11, 0, 20);
395
396 if (debug_kld)
397 printf("%p %c %-24s %08x %08x -> %08x %08x\n",
398 where,
399 (local? 'l': 'g'),
400 reloctype_to_str(rtype),
401 before32, insn32p[0],
402 before32_1, insn32p[1]);
403 break;
404
405 case R_RISCV_PCREL_HI20:
406 val = addr - (Elf_Addr)where;
407 insn32p = (uint32_t*)where;
408 before32 = *insn32p;
409 imm20 = calc_hi20_imm(val);
410 *insn32p = insert_imm(*insn32p, imm20, 31, 12, 12);
411
412 if (debug_kld)
413 printf("%p %c %-24s %08x -> %08x\n",
414 where,
415 (local? 'l': 'g'),
416 reloctype_to_str(rtype),
417 before32, *insn32p);
418 break;
419
420 case R_RISCV_PCREL_LO12_I:
421 val = addr - (Elf_Addr)where;
422 insn32p = (uint32_t*)where;
423 before32 = *insn32p;
424 *insn32p = insert_imm(*insn32p, addr, 11, 0, 20);
425
426 if (debug_kld)
427 printf("%p %c %-24s %08x -> %08x\n",
428 where,
429 (local? 'l': 'g'),
430 reloctype_to_str(rtype),
431 before32, *insn32p);
432 break;
433
434 case R_RISCV_PCREL_LO12_S:
435 val = addr - (Elf_Addr)where;
436 insn32p = (uint32_t*)where;
437 before32 = *insn32p;
438 *insn32p = insert_imm(*insn32p, addr, 11, 5, 25);
439 *insn32p = insert_imm(*insn32p, addr, 4, 0, 7);
440 if (debug_kld)
441 printf("%p %c %-24s %08x -> %08x\n",
442 where,
443 (local? 'l': 'g'),
444 reloctype_to_str(rtype),
445 before32, *insn32p);
446 break;
447
448 case R_RISCV_HI20:
449 error = lookup(lf, symidx, 1, &addr);
450 if (error != 0)
451 return -1;
452
453 insn32p = (uint32_t*)where;
454 before32 = *insn32p;
455 imm20 = calc_hi20_imm(val);
456 *insn32p = insert_imm(*insn32p, imm20, 31, 12, 12);
457
458 if (debug_kld)
459 printf("%p %c %-24s %08x -> %08x\n",
460 where,
461 (local? 'l': 'g'),
462 reloctype_to_str(rtype),
463 before32, *insn32p);
464 break;
465
466 case R_RISCV_LO12_I:
467 error = lookup(lf, symidx, 1, &addr);
468 if (error != 0)
469 return -1;
470
471 val = addr;
472 insn32p = (uint32_t*)where;
473 before32 = *insn32p;
474 *insn32p = insert_imm(*insn32p, addr, 11, 0, 20);
475
476 if (debug_kld)
477 printf("%p %c %-24s %08x -> %08x\n",
478 where,
479 (local? 'l': 'g'),
480 reloctype_to_str(rtype),
481 before32, *insn32p);
482 break;
483
484 case R_RISCV_LO12_S:
485 error = lookup(lf, symidx, 1, &addr);
486 if (error != 0)
487 return -1;
488
489 val = addr;
490 insn32p = (uint32_t*)where;
491 before32 = *insn32p;
492 *insn32p = insert_imm(*insn32p, addr, 11, 5, 25);
493 *insn32p = insert_imm(*insn32p, addr, 4, 0, 7);
494
495 if (debug_kld)
496 printf("%p %c %-24s %08x -> %08x\n",
497 where,
498 (local? 'l': 'g'),
499 reloctype_to_str(rtype),
500 before32, *insn32p);
501 break;
502
503 default:
504 printf("kldload: unexpected relocation type %ld\n", rtype);
505 return (-1);
506 }
507
508 return (0);
509 }
510
511 int
elf_reloc(linker_file_t lf,Elf_Addr relocbase,const void * data,int type,elf_lookup_fn lookup)512 elf_reloc(linker_file_t lf, Elf_Addr relocbase, const void *data, int type,
513 elf_lookup_fn lookup)
514 {
515
516 return (elf_reloc_internal(lf, relocbase, data, type, 0, lookup));
517 }
518
519 int
elf_reloc_local(linker_file_t lf,Elf_Addr relocbase,const void * data,int type,elf_lookup_fn lookup)520 elf_reloc_local(linker_file_t lf, Elf_Addr relocbase, const void *data,
521 int type, elf_lookup_fn lookup)
522 {
523
524 return (elf_reloc_internal(lf, relocbase, data, type, 1, lookup));
525 }
526
527 int
elf_cpu_load_file(linker_file_t lf __unused)528 elf_cpu_load_file(linker_file_t lf __unused)
529 {
530
531 return (0);
532 }
533
534 int
elf_cpu_unload_file(linker_file_t lf __unused)535 elf_cpu_unload_file(linker_file_t lf __unused)
536 {
537
538 return (0);
539 }
540