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/i386/i386/elf_machdep.c 338211 2018-08-22 20:44:30Z markj $");
30
31 #include "opt_cpu.h"
32
33 #include <sys/param.h>
34 #include <sys/kernel.h>
35 #include <sys/systm.h>
36 #include <sys/exec.h>
37 #include <sys/imgact.h>
38 #include <sys/linker.h>
39 #include <sys/proc.h>
40 #include <sys/sysent.h>
41 #include <sys/imgact_elf.h>
42 #include <sys/syscall.h>
43 #include <sys/signalvar.h>
44 #include <sys/vnode.h>
45
46 #include <vm/vm.h>
47 #include <vm/pmap.h>
48 #include <vm/vm_param.h>
49
50 #include <machine/elf.h>
51 #include <machine/md_var.h>
52 #include <machine/npx.h>
53
54 struct sysentvec elf32_freebsd_sysvec = {
55 .sv_size = SYS_MAXSYSCALL,
56 .sv_table = sysent,
57 .sv_mask = 0,
58 .sv_errsize = 0,
59 .sv_errtbl = NULL,
60 .sv_transtrap = NULL,
61 .sv_fixup = __elfN(freebsd_fixup),
62 .sv_sendsig = sendsig,
63 .sv_sigcode = sigcode,
64 .sv_szsigcode = &szsigcode,
65 .sv_name = "FreeBSD ELF32",
66 .sv_coredump = __elfN(coredump),
67 .sv_imgact_try = NULL,
68 .sv_minsigstksz = MINSIGSTKSZ,
69 .sv_pagesize = PAGE_SIZE,
70 .sv_minuser = VM_MIN_ADDRESS,
71 .sv_maxuser = VM_MAXUSER_ADDRESS,
72 .sv_usrstack = USRSTACK,
73 .sv_psstrings = PS_STRINGS,
74 .sv_stackprot = VM_PROT_ALL,
75 .sv_copyout_strings = exec_copyout_strings,
76 .sv_setregs = exec_setregs,
77 .sv_fixlimit = NULL,
78 .sv_maxssiz = NULL,
79 .sv_flags = SV_ABI_FREEBSD | SV_IA32 | SV_ILP32 | SV_SHP |
80 SV_TIMEKEEP,
81 .sv_set_syscall_retval = cpu_set_syscall_retval,
82 .sv_fetch_syscall_args = cpu_fetch_syscall_args,
83 .sv_syscallnames = syscallnames,
84 .sv_shared_page_base = SHAREDPAGE,
85 .sv_shared_page_len = PAGE_SIZE,
86 .sv_schedtail = NULL,
87 .sv_thread_detach = NULL,
88 .sv_trap = NULL,
89 };
90 INIT_SYSENTVEC(elf32_sysvec, &elf32_freebsd_sysvec);
91
92 static Elf32_Brandinfo freebsd_brand_info = {
93 .brand = ELFOSABI_FREEBSD,
94 .machine = EM_386,
95 .compat_3_brand = "FreeBSD",
96 .emul_path = NULL,
97 .interp_path = "/libexec/ld-elf.so.1",
98 .sysvec = &elf32_freebsd_sysvec,
99 .interp_newpath = NULL,
100 .brand_note = &elf32_freebsd_brandnote,
101 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
102 };
103
104 SYSINIT(elf32, SI_SUB_EXEC, SI_ORDER_FIRST,
105 (sysinit_cfunc_t) elf32_insert_brand_entry,
106 &freebsd_brand_info);
107
108 static Elf32_Brandinfo freebsd_brand_oinfo = {
109 .brand = ELFOSABI_FREEBSD,
110 .machine = EM_386,
111 .compat_3_brand = "FreeBSD",
112 .emul_path = NULL,
113 .interp_path = "/usr/libexec/ld-elf.so.1",
114 .sysvec = &elf32_freebsd_sysvec,
115 .interp_newpath = NULL,
116 .brand_note = &elf32_freebsd_brandnote,
117 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
118 };
119
120 SYSINIT(oelf32, SI_SUB_EXEC, SI_ORDER_ANY,
121 (sysinit_cfunc_t) elf32_insert_brand_entry,
122 &freebsd_brand_oinfo);
123
124 static Elf32_Brandinfo kfreebsd_brand_info = {
125 .brand = ELFOSABI_FREEBSD,
126 .machine = EM_386,
127 .compat_3_brand = "FreeBSD",
128 .emul_path = NULL,
129 .interp_path = "/lib/ld.so.1",
130 .sysvec = &elf32_freebsd_sysvec,
131 .interp_newpath = NULL,
132 .brand_note = &elf32_kfreebsd_brandnote,
133 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE_MANDATORY
134 };
135
136 SYSINIT(kelf32, SI_SUB_EXEC, SI_ORDER_ANY,
137 (sysinit_cfunc_t) elf32_insert_brand_entry,
138 &kfreebsd_brand_info);
139
140 void
141 elf32_dump_thread(struct thread *td, void *dst, size_t *off)
142 {
143 void *buf;
144 size_t len;
145
146 len = 0;
147 if (use_xsave) {
148 if (dst != NULL) {
149 npxgetregs(td);
150 len += elf32_populate_note(NT_X86_XSTATE,
151 get_pcb_user_save_td(td), dst,
152 cpu_max_ext_state_size, &buf);
153 *(uint64_t *)((char *)buf + X86_XSTATE_XCR0_OFFSET) =
154 xsave_mask;
155 } else
156 len += elf32_populate_note(NT_X86_XSTATE, NULL, NULL,
157 cpu_max_ext_state_size, NULL);
158 }
159 *off = len;
160 }
161
162 bool
163 elf_is_ifunc_reloc(Elf_Size r_info)
164 {
165
166 return (ELF_R_TYPE(r_info) == R_386_IRELATIVE);
167 }
168
169 #define ERI_LOCAL 0x0001
170
171 /* Process one elf relocation with addend. */
172 static int
173 elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
174 int type, elf_lookup_fn lookup, int flags)
175 {
176 Elf_Addr *where;
177 Elf_Addr addr;
178 Elf_Addr addend;
179 Elf_Word rtype, symidx;
180 const Elf_Rel *rel;
181 const Elf_Rela *rela;
182 int error;
183
184 switch (type) {
185 case ELF_RELOC_REL:
186 rel = (const Elf_Rel *)data;
187 where = (Elf_Addr *) (relocbase + rel->r_offset);
188 addend = *where;
189 rtype = ELF_R_TYPE(rel->r_info);
190 symidx = ELF_R_SYM(rel->r_info);
191 break;
192 case ELF_RELOC_RELA:
193 rela = (const Elf_Rela *)data;
194 where = (Elf_Addr *) (relocbase + rela->r_offset);
195 addend = rela->r_addend;
196 rtype = ELF_R_TYPE(rela->r_info);
197 symidx = ELF_R_SYM(rela->r_info);
198 break;
199 default:
200 panic("unknown reloc type %d\n", type);
201 }
202
203 if ((flags & ERI_LOCAL) != 0) {
204 if (rtype == R_386_RELATIVE) { /* A + B */
205 addr = elf_relocaddr(lf, relocbase + addend);
206 if (*where != addr)
207 *where = addr;
208 }
209 return (0);
210 }
211
212 switch (rtype) {
213
214 case R_386_NONE: /* none */
215 break;
216
217 case R_386_32: /* S + A */
218 error = lookup(lf, symidx, 1, &addr);
219 if (error != 0)
220 return -1;
221 addr += addend;
222 if (*where != addr)
223 *where = addr;
224 break;
225
226 case R_386_PC32: /* S + A - P */
227 error = lookup(lf, symidx, 1, &addr);
228 if (error != 0)
229 return -1;
230 addr += addend - (Elf_Addr)where;
231 if (*where != addr)
232 *where = addr;
233 break;
234
235 case R_386_COPY: /* none */
236 /*
237 * There shouldn't be copy relocations in kernel
238 * objects.
239 */
240 printf("kldload: unexpected R_COPY relocation\n");
241 return -1;
242 break;
243
244 case R_386_GLOB_DAT: /* S */
245 error = lookup(lf, symidx, 1, &addr);
246 if (error != 0)
247 return -1;
248 if (*where != addr)
249 *where = addr;
250 break;
251
252 case R_386_RELATIVE:
253 break;
254
255 case R_386_IRELATIVE:
256 addr = relocbase + addend;
257 addr = ((Elf_Addr (*)(void))addr)();
258 if (*where != addr)
259 *where = addr;
260 break;
261 default:
262 printf("kldload: unexpected relocation type %d\n",
263 rtype);
264 return -1;
265 }
266 return(0);
267 }
268
269 int
270 elf_reloc(linker_file_t lf, Elf_Addr relocbase, const void *data, int type,
271 elf_lookup_fn lookup)
272 {
273
274 return (elf_reloc_internal(lf, relocbase, data, type, lookup, 0));
275 }
276
277 int
278 elf_reloc_local(linker_file_t lf, Elf_Addr relocbase, const void *data,
279 int type, elf_lookup_fn lookup)
280 {
281
282 return (elf_reloc_internal(lf, relocbase, data, type, lookup,
283 ERI_LOCAL));
284 }
285
286 int
287 elf_cpu_load_file(linker_file_t lf __unused)
288 {
289
290 return (0);
291 }
292
293 int
294 elf_cpu_unload_file(linker_file_t lf __unused)
295 {
296
297 return (0);
298 }
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