xref: /freebsd/sys/arm64/arm64/elf_machdep.c (revision 266f97b5)
1 /*-
2  * Copyright (c) 2014, 2015 The FreeBSD Foundation.
3  * Copyright (c) 2014 Andrew Turner.
4  * All rights reserved.
5  *
6  * This software was developed by Andrew Turner under
7  * sponsorship from the FreeBSD Foundation.
8  *
9  * Portions of this software were developed by Konstantin Belousov
10  * under sponsorship from the FreeBSD Foundation.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include <sys/param.h>
38 #include <sys/kernel.h>
39 #include <sys/systm.h>
40 #include <sys/exec.h>
41 #include <sys/imgact.h>
42 #include <sys/linker.h>
43 #include <sys/proc.h>
44 #include <sys/sysent.h>
45 #include <sys/imgact_elf.h>
46 #include <sys/syscall.h>
47 #include <sys/signalvar.h>
48 #include <sys/vnode.h>
49 
50 #include <vm/vm.h>
51 #include <vm/vm_param.h>
52 
53 #include <machine/elf.h>
54 #include <machine/md_var.h>
55 
56 #include "linker_if.h"
57 
58 u_long __read_frequently elf_hwcap;
59 u_long __read_frequently elf_hwcap2;
60 
61 static struct sysentvec elf64_freebsd_sysvec = {
62 	.sv_size	= SYS_MAXSYSCALL,
63 	.sv_table	= sysent,
64 	.sv_transtrap	= NULL,
65 	.sv_fixup	= __elfN(freebsd_fixup),
66 	.sv_sendsig	= sendsig,
67 	.sv_sigcode	= sigcode,
68 	.sv_szsigcode	= &szsigcode,
69 	.sv_name	= "FreeBSD ELF64",
70 	.sv_coredump	= __elfN(coredump),
71 	.sv_elf_core_osabi = ELFOSABI_FREEBSD,
72 	.sv_elf_core_abi_vendor = FREEBSD_ABI_VENDOR,
73 	.sv_elf_core_prepare_notes = __elfN(prepare_notes),
74 	.sv_imgact_try	= NULL,
75 	.sv_minsigstksz	= MINSIGSTKSZ,
76 	.sv_minuser	= VM_MIN_ADDRESS,
77 	.sv_maxuser	= VM_MAXUSER_ADDRESS,
78 	.sv_usrstack	= USRSTACK,
79 	.sv_psstrings	= PS_STRINGS,
80 	.sv_stackprot	= VM_PROT_READ | VM_PROT_WRITE,
81 	.sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs),
82 	.sv_copyout_strings = exec_copyout_strings,
83 	.sv_setregs	= exec_setregs,
84 	.sv_fixlimit	= NULL,
85 	.sv_maxssiz	= NULL,
86 	.sv_flags	= SV_SHP | SV_TIMEKEEP | SV_ABI_FREEBSD | SV_LP64 |
87 	    SV_ASLR | SV_RNG_SEED_VER,
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_stackgap	= elf64_stackgap,
97 	.sv_hwcap	= &elf_hwcap,
98 	.sv_hwcap2	= &elf_hwcap2,
99 	.sv_onexec_old	= exec_onexec_old,
100 	.sv_onexit	= exit_onexit,
101 };
102 INIT_SYSENTVEC(elf64_sysvec, &elf64_freebsd_sysvec);
103 
104 static Elf64_Brandinfo freebsd_brand_info = {
105 	.brand		= ELFOSABI_FREEBSD,
106 	.machine	= EM_AARCH64,
107 	.compat_3_brand	= "FreeBSD",
108 	.emul_path	= NULL,
109 	.interp_path	= "/libexec/ld-elf.so.1",
110 	.sysvec		= &elf64_freebsd_sysvec,
111 	.interp_newpath	= NULL,
112 	.brand_note	= &elf64_freebsd_brandnote,
113 	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
114 };
115 
116 SYSINIT(elf64, SI_SUB_EXEC, SI_ORDER_FIRST,
117     (sysinit_cfunc_t)elf64_insert_brand_entry, &freebsd_brand_info);
118 
119 void
120 elf64_dump_thread(struct thread *td __unused, void *dst __unused,
121     size_t *off __unused)
122 {
123 
124 }
125 
126 bool
127 elf_is_ifunc_reloc(Elf_Size r_info __unused)
128 {
129 
130 	return (ELF_R_TYPE(r_info) == R_AARCH64_IRELATIVE);
131 }
132 
133 static int
134 reloc_instr_imm(Elf32_Addr *where, Elf_Addr val, u_int msb, u_int lsb)
135 {
136 
137 	/* Check bounds: upper bits must be all ones or all zeros. */
138 	if ((uint64_t)((int64_t)val >> (msb + 1)) + 1 > 1)
139 		return (-1);
140 	val >>= lsb;
141 	val &= (1 << (msb - lsb + 1)) - 1;
142 	*where |= (Elf32_Addr)val;
143 	return (0);
144 }
145 
146 /*
147  * Process a relocation.  Support for some static relocations is required
148  * in order for the -zifunc-noplt optimization to work.
149  */
150 static int
151 elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
152     int type, int flags, elf_lookup_fn lookup)
153 {
154 #define	ARM64_ELF_RELOC_LOCAL		(1 << 0)
155 #define	ARM64_ELF_RELOC_LATE_IFUNC	(1 << 1)
156 	Elf_Addr *where, addr, addend, val;
157 	Elf_Word rtype, symidx;
158 	const Elf_Rel *rel;
159 	const Elf_Rela *rela;
160 	int error;
161 
162 	switch (type) {
163 	case ELF_RELOC_REL:
164 		rel = (const Elf_Rel *)data;
165 		where = (Elf_Addr *) (relocbase + rel->r_offset);
166 		addend = *where;
167 		rtype = ELF_R_TYPE(rel->r_info);
168 		symidx = ELF_R_SYM(rel->r_info);
169 		break;
170 	case ELF_RELOC_RELA:
171 		rela = (const Elf_Rela *)data;
172 		where = (Elf_Addr *) (relocbase + rela->r_offset);
173 		addend = rela->r_addend;
174 		rtype = ELF_R_TYPE(rela->r_info);
175 		symidx = ELF_R_SYM(rela->r_info);
176 		break;
177 	default:
178 		panic("unknown reloc type %d\n", type);
179 	}
180 
181 	if ((flags & ARM64_ELF_RELOC_LATE_IFUNC) != 0) {
182 		KASSERT(type == ELF_RELOC_RELA,
183 		    ("Only RELA ifunc relocations are supported"));
184 		if (rtype != R_AARCH64_IRELATIVE)
185 			return (0);
186 	}
187 
188 	if ((flags & ARM64_ELF_RELOC_LOCAL) != 0) {
189 		if (rtype == R_AARCH64_RELATIVE)
190 			*where = elf_relocaddr(lf, relocbase + addend);
191 		return (0);
192 	}
193 
194 	error = 0;
195 	switch (rtype) {
196 	case R_AARCH64_NONE:
197 	case R_AARCH64_RELATIVE:
198 		break;
199 	case R_AARCH64_TSTBR14:
200 		error = lookup(lf, symidx, 1, &addr);
201 		if (error != 0)
202 			return (-1);
203 		error = reloc_instr_imm((Elf32_Addr *)where,
204 		    addr + addend - (Elf_Addr)where, 15, 2);
205 		break;
206 	case R_AARCH64_CONDBR19:
207 		error = lookup(lf, symidx, 1, &addr);
208 		if (error != 0)
209 			return (-1);
210 		error = reloc_instr_imm((Elf32_Addr *)where,
211 		    addr + addend - (Elf_Addr)where, 20, 2);
212 		break;
213 	case R_AARCH64_JUMP26:
214 	case R_AARCH64_CALL26:
215 		error = lookup(lf, symidx, 1, &addr);
216 		if (error != 0)
217 			return (-1);
218 		error = reloc_instr_imm((Elf32_Addr *)where,
219 		    addr + addend - (Elf_Addr)where, 27, 2);
220 		break;
221 	case R_AARCH64_ABS64:
222 	case R_AARCH64_GLOB_DAT:
223 	case R_AARCH64_JUMP_SLOT:
224 		error = lookup(lf, symidx, 1, &addr);
225 		if (error != 0)
226 			return (-1);
227 		*where = addr + addend;
228 		break;
229 	case R_AARCH64_IRELATIVE:
230 		addr = relocbase + addend;
231 		val = ((Elf64_Addr (*)(void))addr)();
232 		if (*where != val)
233 			*where = val;
234 		break;
235 	default:
236 		printf("kldload: unexpected relocation type %d, "
237 		    "symbol index %d\n", rtype, symidx);
238 		return (-1);
239 	}
240 	return (error);
241 }
242 
243 int
244 elf_reloc_local(linker_file_t lf, Elf_Addr relocbase, const void *data,
245     int type, elf_lookup_fn lookup)
246 {
247 
248 	return (elf_reloc_internal(lf, relocbase, data, type,
249 	    ARM64_ELF_RELOC_LOCAL, lookup));
250 }
251 
252 /* Process one elf relocation with addend. */
253 int
254 elf_reloc(linker_file_t lf, Elf_Addr relocbase, const void *data, int type,
255     elf_lookup_fn lookup)
256 {
257 
258 	return (elf_reloc_internal(lf, relocbase, data, type, 0, lookup));
259 }
260 
261 int
262 elf_reloc_late(linker_file_t lf, Elf_Addr relocbase, const void *data,
263     int type, elf_lookup_fn lookup)
264 {
265 
266 	return (elf_reloc_internal(lf, relocbase, data, type,
267 	    ARM64_ELF_RELOC_LATE_IFUNC, lookup));
268 }
269 
270 int
271 elf_cpu_load_file(linker_file_t lf)
272 {
273 
274 	if (lf->id != 1)
275 		cpu_icache_sync_range((vm_offset_t)lf->address, lf->size);
276 	return (0);
277 }
278 
279 int
280 elf_cpu_unload_file(linker_file_t lf __unused)
281 {
282 
283 	return (0);
284 }
285 
286 int
287 elf_cpu_parse_dynamic(caddr_t loadbase __unused, Elf_Dyn *dynamic __unused)
288 {
289 
290 	return (0);
291 }
292