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_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_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 manipulate bits on 32bit integer 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 }
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