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/param.h>
35 #include <sys/kernel.h>
36 #include <sys/systm.h>
37 #include <sys/exec.h>
38 #include <sys/imgact.h>
39 #include <sys/linker.h>
40 #include <sys/proc.h>
41 #include <sys/reg.h>
42 #include <sys/sysent.h>
43 #include <sys/imgact_elf.h>
44 #include <sys/syscall.h>
45 #include <sys/signalvar.h>
46 #include <sys/vnode.h>
47
48 #include <vm/vm.h>
49 #include <vm/pmap.h>
50 #include <vm/vm_param.h>
51 #include <vm/vm_map.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 u_long __read_frequently elf_hwcap3;
61 u_long __read_frequently elf_hwcap4;
62 /* TODO: Move to a better location */
63 u_long __read_frequently linux_elf_hwcap;
64 u_long __read_frequently linux_elf_hwcap2;
65 u_long __read_frequently linux_elf_hwcap3;
66 u_long __read_frequently linux_elf_hwcap4;
67
68 struct arm64_addr_mask elf64_addr_mask;
69
70 static void arm64_exec_protect(struct image_params *, int);
71
72 static struct sysentvec elf64_freebsd_sysvec = {
73 .sv_size = SYS_MAXSYSCALL,
74 .sv_table = sysent,
75 .sv_fixup = __elfN(freebsd_fixup),
76 .sv_sendsig = sendsig,
77 .sv_sigcode = sigcode,
78 .sv_szsigcode = &szsigcode,
79 .sv_name = "FreeBSD ELF64",
80 .sv_coredump = __elfN(coredump),
81 .sv_elf_core_osabi = ELFOSABI_FREEBSD,
82 .sv_elf_core_abi_vendor = FREEBSD_ABI_VENDOR,
83 .sv_elf_core_prepare_notes = __elfN(prepare_notes),
84 .sv_minsigstksz = MINSIGSTKSZ,
85 .sv_minuser = VM_MIN_ADDRESS,
86 .sv_maxuser = VM_MAXUSER_ADDRESS,
87 .sv_usrstack = USRSTACK,
88 .sv_psstrings = PS_STRINGS,
89 .sv_psstringssz = sizeof(struct ps_strings),
90 .sv_stackprot = VM_PROT_READ | VM_PROT_WRITE,
91 .sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs),
92 .sv_copyout_strings = exec_copyout_strings,
93 .sv_setregs = exec_setregs,
94 .sv_fixlimit = NULL,
95 .sv_maxssiz = NULL,
96 .sv_flags = SV_SHP | SV_TIMEKEEP | SV_ABI_FREEBSD | SV_LP64 |
97 SV_ASLR | SV_RNG_SEED_VER | SV_SIGSYS,
98 .sv_set_syscall_retval = cpu_set_syscall_retval,
99 .sv_fetch_syscall_args = cpu_fetch_syscall_args,
100 .sv_syscallnames = syscallnames,
101 .sv_shared_page_base = SHAREDPAGE,
102 .sv_shared_page_len = PAGE_SIZE,
103 .sv_schedtail = NULL,
104 .sv_thread_detach = NULL,
105 .sv_trap = NULL,
106 .sv_hwcap = &elf_hwcap,
107 .sv_hwcap2 = &elf_hwcap2,
108 .sv_hwcap3 = &elf_hwcap3,
109 .sv_hwcap4 = &elf_hwcap4,
110 .sv_onexec_old = exec_onexec_old,
111 .sv_protect = arm64_exec_protect,
112 .sv_onexit = exit_onexit,
113 .sv_regset_begin = SET_BEGIN(__elfN(regset)),
114 .sv_regset_end = SET_LIMIT(__elfN(regset)),
115 };
116 INIT_SYSENTVEC(elf64_sysvec, &elf64_freebsd_sysvec);
117
118 static Elf64_Brandinfo freebsd_brand_info = {
119 .brand = ELFOSABI_FREEBSD,
120 .machine = EM_AARCH64,
121 .compat_3_brand = "FreeBSD",
122 .interp_path = "/libexec/ld-elf.so.1",
123 .sysvec = &elf64_freebsd_sysvec,
124 .interp_newpath = NULL,
125 .brand_note = &elf64_freebsd_brandnote,
126 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE
127 };
128
129 SYSINIT(elf64, SI_SUB_EXEC, SI_ORDER_FIRST,
130 (sysinit_cfunc_t)elf64_insert_brand_entry, &freebsd_brand_info);
131
132 static bool
get_arm64_addr_mask(struct regset * rs,struct thread * td,void * buf,size_t * sizep)133 get_arm64_addr_mask(struct regset *rs, struct thread *td, void *buf,
134 size_t *sizep)
135 {
136 if (buf != NULL) {
137 KASSERT(*sizep == sizeof(elf64_addr_mask),
138 ("%s: invalid size", __func__));
139 memcpy(buf, &elf64_addr_mask, sizeof(elf64_addr_mask));
140 }
141 *sizep = sizeof(elf64_addr_mask);
142
143 return (true);
144 }
145
146 static struct regset regset_arm64_addr_mask = {
147 .note = NT_ARM_ADDR_MASK,
148 .size = sizeof(struct arm64_addr_mask),
149 .get = get_arm64_addr_mask,
150 };
151 ELF_REGSET(regset_arm64_addr_mask);
152
153 void
elf64_dump_thread(struct thread * td __unused,void * dst __unused,size_t * off __unused)154 elf64_dump_thread(struct thread *td __unused, void *dst __unused,
155 size_t *off __unused)
156 {
157 }
158
159 bool
elf_is_ifunc_reloc(Elf_Size r_info __unused)160 elf_is_ifunc_reloc(Elf_Size r_info __unused)
161 {
162
163 return (ELF_R_TYPE(r_info) == R_AARCH64_IRELATIVE);
164 }
165
166 static int
reloc_instr_imm(Elf32_Addr * where,Elf_Addr val,u_int msb,u_int lsb)167 reloc_instr_imm(Elf32_Addr *where, Elf_Addr val, u_int msb, u_int lsb)
168 {
169
170 /* Check bounds: upper bits must be all ones or all zeros. */
171 if ((uint64_t)((int64_t)val >> (msb + 1)) + 1 > 1)
172 return (-1);
173 val >>= lsb;
174 val &= (1 << (msb - lsb + 1)) - 1;
175 *where |= (Elf32_Addr)val;
176 return (0);
177 }
178
179 /*
180 * Process a relocation. Support for some static relocations is required
181 * in order for the -zifunc-noplt optimization to work.
182 */
183 static int
elf_reloc_internal(linker_file_t lf,Elf_Addr relocbase,const void * data,int type,int flags,elf_lookup_fn lookup)184 elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
185 int type, int flags, elf_lookup_fn lookup)
186 {
187 #define ARM64_ELF_RELOC_LOCAL (1 << 0)
188 #define ARM64_ELF_RELOC_LATE_IFUNC (1 << 1)
189 Elf_Addr *where, addr, addend, val;
190 Elf_Word rtype, symidx;
191 const Elf_Rel *rel;
192 const Elf_Rela *rela;
193 int error;
194
195 switch (type) {
196 case ELF_RELOC_REL:
197 rel = (const Elf_Rel *)data;
198 where = (Elf_Addr *) (relocbase + rel->r_offset);
199 addend = *where;
200 rtype = ELF_R_TYPE(rel->r_info);
201 symidx = ELF_R_SYM(rel->r_info);
202 break;
203 case ELF_RELOC_RELA:
204 rela = (const Elf_Rela *)data;
205 where = (Elf_Addr *) (relocbase + rela->r_offset);
206 addend = rela->r_addend;
207 rtype = ELF_R_TYPE(rela->r_info);
208 symidx = ELF_R_SYM(rela->r_info);
209 break;
210 default:
211 panic("unknown reloc type %d\n", type);
212 }
213
214 if ((flags & ARM64_ELF_RELOC_LATE_IFUNC) != 0) {
215 KASSERT(type == ELF_RELOC_RELA,
216 ("Only RELA ifunc relocations are supported"));
217 if (rtype != R_AARCH64_IRELATIVE)
218 return (0);
219 }
220
221 if ((flags & ARM64_ELF_RELOC_LOCAL) != 0) {
222 if (rtype == R_AARCH64_RELATIVE)
223 *where = elf_relocaddr(lf, relocbase + addend);
224 return (0);
225 }
226
227 error = 0;
228 switch (rtype) {
229 case R_AARCH64_NONE:
230 case R_AARCH64_RELATIVE:
231 break;
232 case R_AARCH64_TSTBR14:
233 error = lookup(lf, symidx, 1, &addr);
234 if (error != 0)
235 return (-1);
236 error = reloc_instr_imm((Elf32_Addr *)where,
237 addr + addend - (Elf_Addr)where, 15, 2);
238 break;
239 case R_AARCH64_CONDBR19:
240 error = lookup(lf, symidx, 1, &addr);
241 if (error != 0)
242 return (-1);
243 error = reloc_instr_imm((Elf32_Addr *)where,
244 addr + addend - (Elf_Addr)where, 20, 2);
245 break;
246 case R_AARCH64_JUMP26:
247 case R_AARCH64_CALL26:
248 error = lookup(lf, symidx, 1, &addr);
249 if (error != 0)
250 return (-1);
251 error = reloc_instr_imm((Elf32_Addr *)where,
252 addr + addend - (Elf_Addr)where, 27, 2);
253 break;
254 case R_AARCH64_ABS64:
255 case R_AARCH64_GLOB_DAT:
256 case R_AARCH64_JUMP_SLOT:
257 error = lookup(lf, symidx, 1, &addr);
258 if (error != 0)
259 return (-1);
260 *where = addr + addend;
261 break;
262 case R_AARCH64_IRELATIVE:
263 addr = relocbase + addend;
264 val = ((Elf64_Addr (*)(void))addr)();
265 if (*where != val)
266 *where = val;
267 break;
268 default:
269 printf("kldload: unexpected relocation type %d, "
270 "symbol index %d\n", rtype, symidx);
271 return (-1);
272 }
273 return (error);
274 }
275
276 int
elf_reloc_local(linker_file_t lf,Elf_Addr relocbase,const void * data,int type,elf_lookup_fn lookup)277 elf_reloc_local(linker_file_t lf, Elf_Addr relocbase, const void *data,
278 int type, elf_lookup_fn lookup)
279 {
280
281 return (elf_reloc_internal(lf, relocbase, data, type,
282 ARM64_ELF_RELOC_LOCAL, lookup));
283 }
284
285 /* Process one elf relocation with addend. */
286 int
elf_reloc(linker_file_t lf,Elf_Addr relocbase,const void * data,int type,elf_lookup_fn lookup)287 elf_reloc(linker_file_t lf, Elf_Addr relocbase, const void *data, int type,
288 elf_lookup_fn lookup)
289 {
290
291 return (elf_reloc_internal(lf, relocbase, data, type, 0, lookup));
292 }
293
294 int
elf_reloc_late(linker_file_t lf,Elf_Addr relocbase,const void * data,int type,elf_lookup_fn lookup)295 elf_reloc_late(linker_file_t lf, Elf_Addr relocbase, const void *data,
296 int type, elf_lookup_fn lookup)
297 {
298
299 return (elf_reloc_internal(lf, relocbase, data, type,
300 ARM64_ELF_RELOC_LATE_IFUNC, lookup));
301 }
302
303 int
elf_cpu_load_file(linker_file_t lf)304 elf_cpu_load_file(linker_file_t lf)
305 {
306
307 if (lf->id != 1)
308 cpu_icache_sync_range(lf->address, lf->size);
309 return (0);
310 }
311
312 int
elf_cpu_unload_file(linker_file_t lf __unused)313 elf_cpu_unload_file(linker_file_t lf __unused)
314 {
315
316 return (0);
317 }
318
319 int
elf_cpu_parse_dynamic(caddr_t loadbase __unused,Elf_Dyn * dynamic __unused)320 elf_cpu_parse_dynamic(caddr_t loadbase __unused, Elf_Dyn *dynamic __unused)
321 {
322
323 return (0);
324 }
325
326 static Elf_Note gnu_property_note = {
327 .n_namesz = sizeof(GNU_ABI_VENDOR),
328 .n_descsz = 16,
329 .n_type = NT_GNU_PROPERTY_TYPE_0,
330 };
331
332 static bool
gnu_property_cb(const Elf_Note * note,void * arg0,bool * res)333 gnu_property_cb(const Elf_Note *note, void *arg0, bool *res)
334 {
335 const uint32_t *data;
336 uintptr_t p;
337
338 *res = false;
339 p = (uintptr_t)(note + 1);
340 p += roundup2(note->n_namesz, 4);
341 data = (const uint32_t *)p;
342 if (data[0] != GNU_PROPERTY_AARCH64_FEATURE_1_AND)
343 return (false);
344 /*
345 * The data length should be at least the size of a uint32, and be
346 * a multiple of uint32_t's
347 */
348 if (data[1] < sizeof(uint32_t) || (data[1] % sizeof(uint32_t)) != 0)
349 return (false);
350 if ((data[2] & GNU_PROPERTY_AARCH64_FEATURE_1_BTI) != 0)
351 *res = true;
352
353 return (true);
354 }
355
356 static void
arm64_exec_protect(struct image_params * imgp,int flags __unused)357 arm64_exec_protect(struct image_params *imgp, int flags __unused)
358 {
359 const Elf_Ehdr *hdr;
360 const Elf_Phdr *phdr;
361 vm_offset_t sva, eva;
362 int i;
363 bool found;
364
365 /* Skip if BTI is not supported */
366 if ((elf_hwcap2 & HWCAP2_BTI) == 0)
367 return;
368
369 hdr = (const Elf_Ehdr *)imgp->image_header;
370 phdr = (const Elf_Phdr *)(imgp->image_header + hdr->e_phoff);
371
372 found = false;
373 for (i = 0; i < hdr->e_phnum; i++) {
374 if (phdr[i].p_type == PT_NOTE && __elfN(parse_notes)(imgp,
375 &gnu_property_note, GNU_ABI_VENDOR, &phdr[i],
376 gnu_property_cb, NULL)) {
377 found = true;
378 break;
379 }
380 }
381 if (!found)
382 return;
383
384 for (i = 0; i < hdr->e_phnum; i++) {
385 if (phdr[i].p_type != PT_LOAD || phdr[i].p_memsz == 0)
386 continue;
387
388 sva = phdr[i].p_vaddr + imgp->et_dyn_addr;
389 eva = sva + phdr[i].p_memsz;
390 pmap_bti_set(vmspace_pmap(imgp->proc->p_vmspace), sva, eva);
391 }
392 }
393