xref: /freebsd/sys/amd64/amd64/elf_machdep.c (revision 7bd6fde3)
1 /*-
2  * Copyright 1996-1998 John D. Polstra.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
28 
29 #include <sys/param.h>
30 #include <sys/kernel.h>
31 #include <sys/systm.h>
32 #include <sys/exec.h>
33 #include <sys/imgact.h>
34 #include <sys/linker.h>
35 #include <sys/sysent.h>
36 #include <sys/imgact_elf.h>
37 #include <sys/syscall.h>
38 #include <sys/signalvar.h>
39 #include <sys/vnode.h>
40 
41 #include <vm/vm.h>
42 #include <vm/pmap.h>
43 #include <vm/vm_param.h>
44 
45 #include <machine/elf.h>
46 #include <machine/md_var.h>
47 
48 struct sysentvec elf64_freebsd_sysvec = {
49 	SYS_MAXSYSCALL,
50 	sysent,
51 	0,
52 	0,
53 	NULL,
54 	0,
55 	NULL,
56 	NULL,
57 	__elfN(freebsd_fixup),
58 	sendsig,
59 	sigcode,
60 	&szsigcode,
61 	NULL,
62 	"FreeBSD ELF64",
63 	__elfN(coredump),
64 	NULL,
65 	MINSIGSTKSZ,
66 	PAGE_SIZE,
67 	VM_MIN_ADDRESS,
68 	VM_MAXUSER_ADDRESS,
69 	USRSTACK,
70 	PS_STRINGS,
71 	VM_PROT_ALL,
72 	exec_copyout_strings,
73 	exec_setregs,
74 	NULL
75 };
76 
77 static Elf64_Brandinfo freebsd_brand_info = {
78 						ELFOSABI_FREEBSD,
79 						EM_X86_64,
80 						"FreeBSD",
81 						NULL,
82 						"/libexec/ld-elf.so.1",
83 						&elf64_freebsd_sysvec,
84 						NULL,
85 						0,
86 					  };
87 
88 SYSINIT(elf64, SI_SUB_EXEC, SI_ORDER_ANY,
89 	(sysinit_cfunc_t) elf64_insert_brand_entry,
90 	&freebsd_brand_info);
91 
92 static Elf64_Brandinfo freebsd_brand_oinfo = {
93 						ELFOSABI_FREEBSD,
94 						EM_X86_64,
95 						"FreeBSD",
96 						NULL,
97 						"/usr/libexec/ld-elf.so.1",
98 						&elf64_freebsd_sysvec,
99 						NULL,
100 						0,
101 					  };
102 
103 SYSINIT(oelf64, SI_SUB_EXEC, SI_ORDER_ANY,
104 	(sysinit_cfunc_t) elf64_insert_brand_entry,
105 	&freebsd_brand_oinfo);
106 
107 
108 void
109 elf64_dump_thread(struct thread *td __unused, void *dst __unused,
110     size_t *off __unused)
111 {
112 }
113 
114 
115 /* Process one elf relocation with addend. */
116 static int
117 elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
118     int type, int local, elf_lookup_fn lookup)
119 {
120 	Elf64_Addr *where, val;
121 	Elf32_Addr *where32, val32;
122 	Elf_Addr addr;
123 	Elf_Addr addend;
124 	Elf_Size rtype, symidx;
125 	const Elf_Rel *rel;
126 	const Elf_Rela *rela;
127 
128 	switch (type) {
129 	case ELF_RELOC_REL:
130 		rel = (const Elf_Rel *)data;
131 		where = (Elf_Addr *) (relocbase + rel->r_offset);
132 		rtype = ELF_R_TYPE(rel->r_info);
133 		symidx = ELF_R_SYM(rel->r_info);
134 		/* Addend is 32 bit on 32 bit relocs */
135 		switch (rtype) {
136 		case R_X86_64_PC32:
137 		case R_X86_64_32S:
138 			addend = *(Elf32_Addr *)where;
139 			break;
140 		default:
141 			addend = *where;
142 			break;
143 		}
144 		break;
145 	case ELF_RELOC_RELA:
146 		rela = (const Elf_Rela *)data;
147 		where = (Elf_Addr *) (relocbase + rela->r_offset);
148 		addend = rela->r_addend;
149 		rtype = ELF_R_TYPE(rela->r_info);
150 		symidx = ELF_R_SYM(rela->r_info);
151 		break;
152 	default:
153 		panic("unknown reloc type %d\n", type);
154 	}
155 
156 	switch (rtype) {
157 
158 		case R_X86_64_NONE:	/* none */
159 			break;
160 
161 		case R_X86_64_64:		/* S + A */
162 			addr = lookup(lf, symidx, 1);
163 			val = addr + addend;
164 			if (addr == 0)
165 				return -1;
166 			if (*where != val)
167 				*where = val;
168 			break;
169 
170 		case R_X86_64_PC32:	/* S + A - P */
171 			addr = lookup(lf, symidx, 1);
172 			where32 = (Elf32_Addr *)where;
173 			val32 = (Elf32_Addr)(addr + addend - (Elf_Addr)where);
174 			if (addr == 0)
175 				return -1;
176 			if (*where32 != val32)
177 				*where32 = val32;
178 			break;
179 
180 		case R_X86_64_32S:	/* S + A sign extend */
181 			addr = lookup(lf, symidx, 1);
182 			val32 = (Elf32_Addr)(addr + addend);
183 			where32 = (Elf32_Addr *)where;
184 			if (addr == 0)
185 				return -1;
186 			if (*where32 != val32)
187 				*where32 = val32;
188 			break;
189 
190 		case R_X86_64_COPY:	/* none */
191 			/*
192 			 * There shouldn't be copy relocations in kernel
193 			 * objects.
194 			 */
195 			printf("kldload: unexpected R_COPY relocation\n");
196 			return -1;
197 			break;
198 
199 		case R_X86_64_GLOB_DAT:	/* S */
200 		case R_X86_64_JMP_SLOT:	/* XXX need addend + offset */
201 			addr = lookup(lf, symidx, 1);
202 			if (addr == 0)
203 				return -1;
204 			if (*where != addr)
205 				*where = addr;
206 			break;
207 
208 		case R_X86_64_RELATIVE:	/* B + A */
209 			addr = relocbase + addend;
210 			val = addr;
211 			if (*where != val)
212 				*where = val;
213 			break;
214 
215 		default:
216 			printf("kldload: unexpected relocation type %ld\n",
217 			       rtype);
218 			return -1;
219 	}
220 	return(0);
221 }
222 
223 int
224 elf_reloc(linker_file_t lf, Elf_Addr relocbase, const void *data, int type,
225     elf_lookup_fn lookup)
226 {
227 
228 	return (elf_reloc_internal(lf, relocbase, data, type, 0, lookup));
229 }
230 
231 int
232 elf_reloc_local(linker_file_t lf, Elf_Addr relocbase, const void *data,
233     int type, elf_lookup_fn lookup)
234 {
235 
236 	return (elf_reloc_internal(lf, relocbase, data, type, 1, lookup));
237 }
238 
239 int
240 elf_cpu_load_file(linker_file_t lf __unused)
241 {
242 
243 	return (0);
244 }
245 
246 int
247 elf_cpu_unload_file(linker_file_t lf __unused)
248 {
249 
250 	return (0);
251 }
252