1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright 1996-1998 John D. Polstra.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD: releng/12.0/sys/amd64/amd64/elf_machdep.c 338211 2018-08-22 20:44:30Z markj $");
30
31 #include <sys/param.h>
32 #include <sys/kernel.h>
33 #include <sys/systm.h>
34 #include <sys/exec.h>
35 #include <sys/imgact.h>
36 #include <sys/linker.h>
37 #include <sys/proc.h>
38 #include <sys/sysent.h>
39 #include <sys/imgact_elf.h>
40 #include <sys/syscall.h>
41 #include <sys/signalvar.h>
42 #include <sys/vnode.h>
43
44 #include <vm/vm.h>
45 #include <vm/pmap.h>
46 #include <vm/vm_param.h>
47
48 #include <machine/elf.h>
49 #include <machine/fpu.h>
50 #include <machine/md_var.h>
51
52 struct sysentvec elf64_freebsd_sysvec = {
53 .sv_size = SYS_MAXSYSCALL,
54 .sv_table = sysent,
55 .sv_mask = 0,
56 .sv_errsize = 0,
57 .sv_errtbl = NULL,
58 .sv_transtrap = NULL,
59 .sv_fixup = __elfN(freebsd_fixup),
60 .sv_sendsig = sendsig,
61 .sv_sigcode = sigcode,
62 .sv_szsigcode = &szsigcode,
63 .sv_name = "FreeBSD ELF64",
64 .sv_coredump = __elfN(coredump),
65 .sv_imgact_try = NULL,
66 .sv_minsigstksz = MINSIGSTKSZ,
67 .sv_pagesize = PAGE_SIZE,
68 .sv_minuser = VM_MIN_ADDRESS,
69 .sv_maxuser = VM_MAXUSER_ADDRESS,
70 .sv_usrstack = USRSTACK,
71 .sv_psstrings = PS_STRINGS,
72 .sv_stackprot = VM_PROT_ALL,
73 .sv_copyout_strings = exec_copyout_strings,
74 .sv_setregs = exec_setregs,
75 .sv_fixlimit = NULL,
76 .sv_maxssiz = NULL,
77 .sv_flags = SV_ABI_FREEBSD | SV_LP64 | SV_SHP | SV_TIMEKEEP,
78 .sv_set_syscall_retval = cpu_set_syscall_retval,
79 .sv_fetch_syscall_args = cpu_fetch_syscall_args,
80 .sv_syscallnames = syscallnames,
81 .sv_shared_page_base = SHAREDPAGE,
82 .sv_shared_page_len = PAGE_SIZE,
83 .sv_schedtail = NULL,
84 .sv_thread_detach = NULL,
85 .sv_trap = NULL,
86 };
87 INIT_SYSENTVEC(elf64_sysvec, &elf64_freebsd_sysvec);
88
89 void
90 amd64_lower_shared_page(struct sysentvec *sv)
91 {
92 if (hw_lower_amd64_sharedpage != 0) {
93 sv->sv_maxuser -= PAGE_SIZE;
94 sv->sv_shared_page_base -= PAGE_SIZE;
95 sv->sv_usrstack -= PAGE_SIZE;
96 sv->sv_psstrings -= PAGE_SIZE;
97 }
98 }
99
100 /*
101 * Do this fixup before INIT_SYSENTVEC (SI_ORDER_ANY) because the latter
102 * uses the value of sv_shared_page_base.
103 */
104 SYSINIT(elf64_sysvec_fixup, SI_SUB_EXEC, SI_ORDER_FIRST,
105 (sysinit_cfunc_t) amd64_lower_shared_page,
106 &elf64_freebsd_sysvec);
107
108 static Elf64_Brandinfo freebsd_brand_info = {
109 .brand = ELFOSABI_FREEBSD,
110 .machine = EM_X86_64,
111 .compat_3_brand = "FreeBSD",
112 .emul_path = NULL,
113 .interp_path = "/libexec/ld-elf.so.1",
114 .sysvec = &elf64_freebsd_sysvec,
115 .interp_newpath = NULL,
116 .brand_note = &elf64_freebsd_brandnote,
117 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
118 };
119
120 SYSINIT(elf64, SI_SUB_EXEC, SI_ORDER_FIRST,
121 (sysinit_cfunc_t) elf64_insert_brand_entry,
122 &freebsd_brand_info);
123
124 static Elf64_Brandinfo freebsd_brand_oinfo = {
125 .brand = ELFOSABI_FREEBSD,
126 .machine = EM_X86_64,
127 .compat_3_brand = "FreeBSD",
128 .emul_path = NULL,
129 .interp_path = "/usr/libexec/ld-elf.so.1",
130 .sysvec = &elf64_freebsd_sysvec,
131 .interp_newpath = NULL,
132 .brand_note = &elf64_freebsd_brandnote,
133 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
134 };
135
136 SYSINIT(oelf64, SI_SUB_EXEC, SI_ORDER_ANY,
137 (sysinit_cfunc_t) elf64_insert_brand_entry,
138 &freebsd_brand_oinfo);
139
140 static Elf64_Brandinfo kfreebsd_brand_info = {
141 .brand = ELFOSABI_FREEBSD,
142 .machine = EM_X86_64,
143 .compat_3_brand = "FreeBSD",
144 .emul_path = NULL,
145 .interp_path = "/lib/ld-kfreebsd-x86-64.so.1",
146 .sysvec = &elf64_freebsd_sysvec,
147 .interp_newpath = NULL,
148 .brand_note = &elf64_kfreebsd_brandnote,
149 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE_MANDATORY
150 };
151
152 SYSINIT(kelf64, SI_SUB_EXEC, SI_ORDER_ANY,
153 (sysinit_cfunc_t) elf64_insert_brand_entry,
154 &kfreebsd_brand_info);
155
156 void
157 elf64_dump_thread(struct thread *td, void *dst, size_t *off)
158 {
159 void *buf;
160 size_t len;
161
162 len = 0;
163 if (use_xsave) {
164 if (dst != NULL) {
165 fpugetregs(td);
166 len += elf64_populate_note(NT_X86_XSTATE,
167 get_pcb_user_save_td(td), dst,
168 cpu_max_ext_state_size, &buf);
169 *(uint64_t *)((char *)buf + X86_XSTATE_XCR0_OFFSET) =
170 xsave_mask;
171 } else
172 len += elf64_populate_note(NT_X86_XSTATE, NULL, NULL,
173 cpu_max_ext_state_size, NULL);
174 }
175 *off = len;
176 }
177
178 bool
179 elf_is_ifunc_reloc(Elf_Size r_info)
180 {
181
182 return (ELF_R_TYPE(r_info) == R_X86_64_IRELATIVE);
183 }
184
185 /* Process one elf relocation with addend. */
186 static int
187 elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
188 int type, elf_lookup_fn lookup)
189 {
190 Elf64_Addr *where, val;
191 Elf32_Addr *where32, val32;
192 Elf_Addr addr;
193 Elf_Addr addend;
194 Elf_Size rtype, symidx;
195 const Elf_Rel *rel;
196 const Elf_Rela *rela;
197 int error;
198
199 switch (type) {
200 case ELF_RELOC_REL:
201 rel = (const Elf_Rel *)data;
202 where = (Elf_Addr *) (relocbase + rel->r_offset);
203 rtype = ELF_R_TYPE(rel->r_info);
204 symidx = ELF_R_SYM(rel->r_info);
205 /* Addend is 32 bit on 32 bit relocs */
206 switch (rtype) {
207 case R_X86_64_PC32:
208 case R_X86_64_32S:
209 case R_X86_64_PLT32:
210 addend = *(Elf32_Addr *)where;
211 break;
212 default:
213 addend = *where;
214 break;
215 }
216 break;
217 case ELF_RELOC_RELA:
218 rela = (const Elf_Rela *)data;
219 where = (Elf_Addr *) (relocbase + rela->r_offset);
220 addend = rela->r_addend;
221 rtype = ELF_R_TYPE(rela->r_info);
222 symidx = ELF_R_SYM(rela->r_info);
223 break;
224 default:
225 panic("unknown reloc type %d\n", type);
226 }
227
228 switch (rtype) {
229 case R_X86_64_NONE: /* none */
230 break;
231
232 case R_X86_64_64: /* S + A */
233 error = lookup(lf, symidx, 1, &addr);
234 val = addr + addend;
235 if (error != 0)
236 return -1;
237 if (*where != val)
238 *where = val;
239 break;
240
241 case R_X86_64_PC32: /* S + A - P */
242 case R_X86_64_PLT32: /* L + A - P, L is PLT location for
243 the symbol, which we treat as S */
244 error = lookup(lf, symidx, 1, &addr);
245 where32 = (Elf32_Addr *)where;
246 val32 = (Elf32_Addr)(addr + addend - (Elf_Addr)where);
247 if (error != 0)
248 return -1;
249 if (*where32 != val32)
250 *where32 = val32;
251 break;
252
253 case R_X86_64_32S: /* S + A sign extend */
254 error = lookup(lf, symidx, 1, &addr);
255 val32 = (Elf32_Addr)(addr + addend);
256 where32 = (Elf32_Addr *)where;
257 if (error != 0)
258 return -1;
259 if (*where32 != val32)
260 *where32 = val32;
261 break;
262
263 case R_X86_64_COPY: /* none */
264 /*
265 * There shouldn't be copy relocations in kernel
266 * objects.
267 */
268 printf("kldload: unexpected R_COPY relocation\n");
269 return (-1);
270 break;
271
272 case R_X86_64_GLOB_DAT: /* S */
273 case R_X86_64_JMP_SLOT: /* XXX need addend + offset */
274 error = lookup(lf, symidx, 1, &addr);
275 if (error != 0)
276 return -1;
277 if (*where != addr)
278 *where = addr;
279 break;
280
281 case R_X86_64_RELATIVE: /* B + A */
282 addr = relocbase + addend;
283 val = addr;
284 if (*where != val)
285 *where = val;
286 break;
287
288 case R_X86_64_IRELATIVE:
289 addr = relocbase + addend;
290 val = ((Elf64_Addr (*)(void))addr)();
291 if (*where != val)
292 *where = val;
293 break;
294
295 default:
296 printf("kldload: unexpected relocation type %ld\n",
297 rtype);
298 return (-1);
299 }
300 return (0);
301 }
302
303 int
304 elf_reloc(linker_file_t lf, Elf_Addr relocbase, const void *data, int type,
305 elf_lookup_fn lookup)
306 {
307
308 return (elf_reloc_internal(lf, relocbase, data, type, lookup));
309 }
310
311 int
312 elf_reloc_local(linker_file_t lf, Elf_Addr relocbase, const void *data,
313 int type, elf_lookup_fn lookup)
314 {
315
316 return (elf_reloc_internal(lf, relocbase, data, type, lookup));
317 }
318
319 int
320 elf_cpu_load_file(linker_file_t lf __unused)
321 {
322
323 return (0);
324 }
325
326 int
327 elf_cpu_unload_file(linker_file_t lf __unused)
328 {
329
330 return (0);
331 }
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