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("$FreeBSD$");
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/sysent.h>
38 #include <sys/imgact_elf.h>
39 #include <sys/proc.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/md_var.h>
50 #include <machine/stack.h>
51 #ifdef VFP
52 #include <machine/vfp.h>
53 #endif
54
55 #include "opt_ddb.h" /* for OPT_DDB */
56 #include "opt_global.h" /* for OPT_KDTRACE_HOOKS */
57 #include "opt_stack.h" /* for OPT_STACK */
58
59 static boolean_t elf32_arm_abi_supported(struct image_params *, int32_t *,
60 uint32_t *);
61
62 u_long elf_hwcap;
63 u_long elf_hwcap2;
64
65 struct sysentvec elf32_freebsd_sysvec = {
66 .sv_size = SYS_MAXSYSCALL,
67 .sv_table = sysent,
68 .sv_transtrap = NULL,
69 .sv_fixup = __elfN(freebsd_fixup),
70 .sv_sendsig = sendsig,
71 .sv_sigcode = sigcode,
72 .sv_szsigcode = &szsigcode,
73 .sv_name = "FreeBSD ELF32",
74 .sv_coredump = __elfN(coredump),
75 .sv_imgact_try = NULL,
76 .sv_minsigstksz = MINSIGSTKSZ,
77 .sv_minuser = VM_MIN_ADDRESS,
78 .sv_maxuser = VM_MAXUSER_ADDRESS,
79 .sv_usrstack = USRSTACK,
80 .sv_psstrings = PS_STRINGS,
81 .sv_stackprot = VM_PROT_ALL,
82 .sv_copyout_auxargs = __elfN(freebsd_copyout_auxargs),
83 .sv_copyout_strings = exec_copyout_strings,
84 .sv_setregs = exec_setregs,
85 .sv_fixlimit = NULL,
86 .sv_maxssiz = NULL,
87 .sv_flags =
88 SV_ASLR | SV_SHP | SV_TIMEKEEP | SV_RNG_SEED_VER |
89 SV_ABI_FREEBSD | SV_ILP32,
90 .sv_set_syscall_retval = cpu_set_syscall_retval,
91 .sv_fetch_syscall_args = cpu_fetch_syscall_args,
92 .sv_syscallnames = syscallnames,
93 .sv_shared_page_base = SHAREDPAGE,
94 .sv_shared_page_len = PAGE_SIZE,
95 .sv_schedtail = NULL,
96 .sv_thread_detach = NULL,
97 .sv_trap = NULL,
98 .sv_hwcap = &elf_hwcap,
99 .sv_hwcap2 = &elf_hwcap2,
100 };
101 INIT_SYSENTVEC(elf32_sysvec, &elf32_freebsd_sysvec);
102
103 static Elf32_Brandinfo freebsd_brand_info = {
104 .brand = ELFOSABI_FREEBSD,
105 .machine = EM_ARM,
106 .compat_3_brand = "FreeBSD",
107 .emul_path = NULL,
108 .interp_path = "/libexec/ld-elf.so.1",
109 .sysvec = &elf32_freebsd_sysvec,
110 .interp_newpath = NULL,
111 .brand_note = &elf32_freebsd_brandnote,
112 .flags = BI_CAN_EXEC_DYN | BI_BRAND_NOTE,
113 .header_supported= elf32_arm_abi_supported,
114 };
115
116 SYSINIT(elf32, SI_SUB_EXEC, SI_ORDER_FIRST,
117 (sysinit_cfunc_t) elf32_insert_brand_entry,
118 &freebsd_brand_info);
119
120 static boolean_t
elf32_arm_abi_supported(struct image_params * imgp,int32_t * osrel __unused,uint32_t * fctl0 __unused)121 elf32_arm_abi_supported(struct image_params *imgp, int32_t *osrel __unused,
122 uint32_t *fctl0 __unused)
123 {
124 const Elf_Ehdr *hdr = (const Elf_Ehdr *)imgp->image_header;
125
126 /*
127 * When configured for EABI, FreeBSD supports EABI vesions 4 and 5.
128 */
129 if (EF_ARM_EABI_VERSION(hdr->e_flags) < EF_ARM_EABI_FREEBSD_MIN) {
130 if (bootverbose)
131 uprintf("Attempting to execute non EABI binary (rev %d) image %s",
132 EF_ARM_EABI_VERSION(hdr->e_flags), imgp->args->fname);
133 return (FALSE);
134 }
135 return (TRUE);
136 }
137
138 void
elf32_dump_thread(struct thread * td,void * dst,size_t * off)139 elf32_dump_thread(struct thread *td, void *dst, size_t *off)
140 {
141 #ifdef VFP
142 mcontext_vfp_t vfp;
143
144 if (dst != NULL) {
145 get_vfpcontext(td, &vfp);
146 *off = elf32_populate_note(NT_ARM_VFP, &vfp, dst, sizeof(vfp),
147 NULL);
148 } else
149 *off = elf32_populate_note(NT_ARM_VFP, NULL, NULL, sizeof(vfp),
150 NULL);
151 #endif
152 }
153
154 bool
elf_is_ifunc_reloc(Elf_Size r_info __unused)155 elf_is_ifunc_reloc(Elf_Size r_info __unused)
156 {
157
158 return (false);
159 }
160
161 /*
162 * It is possible for the compiler to emit relocations for unaligned data.
163 * We handle this situation with these inlines.
164 */
165 #define RELOC_ALIGNED_P(x) \
166 (((uintptr_t)(x) & (sizeof(void *) - 1)) == 0)
167
168 static __inline Elf_Addr
load_ptr(Elf_Addr * where)169 load_ptr(Elf_Addr *where)
170 {
171 Elf_Addr res;
172
173 if (RELOC_ALIGNED_P(where))
174 return *where;
175 memcpy(&res, where, sizeof(res));
176 return (res);
177 }
178
179 static __inline void
store_ptr(Elf_Addr * where,Elf_Addr val)180 store_ptr(Elf_Addr *where, Elf_Addr val)
181 {
182 if (RELOC_ALIGNED_P(where))
183 *where = val;
184 else
185 memcpy(where, &val, sizeof(val));
186 }
187 #undef RELOC_ALIGNED_P
188
189 /* Process one elf relocation with addend. */
190 static int
elf_reloc_internal(linker_file_t lf,Elf_Addr relocbase,const void * data,int type,int local,elf_lookup_fn lookup)191 elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
192 int type, int local, elf_lookup_fn lookup)
193 {
194 Elf_Addr *where;
195 Elf_Addr addr;
196 Elf_Addr addend;
197 Elf_Word rtype, symidx;
198 const Elf_Rel *rel;
199 const Elf_Rela *rela;
200 int error;
201
202 switch (type) {
203 case ELF_RELOC_REL:
204 rel = (const Elf_Rel *)data;
205 where = (Elf_Addr *) (relocbase + rel->r_offset);
206 addend = load_ptr(where);
207 rtype = ELF_R_TYPE(rel->r_info);
208 symidx = ELF_R_SYM(rel->r_info);
209 break;
210 case ELF_RELOC_RELA:
211 rela = (const Elf_Rela *)data;
212 where = (Elf_Addr *) (relocbase + rela->r_offset);
213 addend = rela->r_addend;
214 rtype = ELF_R_TYPE(rela->r_info);
215 symidx = ELF_R_SYM(rela->r_info);
216 break;
217 default:
218 panic("unknown reloc type %d\n", type);
219 }
220
221 if (local) {
222 if (rtype == R_ARM_RELATIVE) { /* A + B */
223 addr = elf_relocaddr(lf, relocbase + addend);
224 if (load_ptr(where) != addr)
225 store_ptr(where, addr);
226 }
227 return (0);
228 }
229
230 switch (rtype) {
231 case R_ARM_NONE: /* none */
232 break;
233
234 case R_ARM_ABS32:
235 error = lookup(lf, symidx, 1, &addr);
236 if (error != 0)
237 return (-1);
238 store_ptr(where, addr + load_ptr(where));
239 break;
240
241 case R_ARM_COPY: /* none */
242 /*
243 * There shouldn't be copy relocations in kernel
244 * objects.
245 */
246 printf("kldload: unexpected R_COPY relocation, "
247 "symbol index %d\n", symidx);
248 return (-1);
249 break;
250
251 case R_ARM_JUMP_SLOT:
252 error = lookup(lf, symidx, 1, &addr);
253 if (error == 0) {
254 store_ptr(where, addr);
255 return (0);
256 }
257 return (-1);
258 case R_ARM_RELATIVE:
259 break;
260
261 default:
262 printf("kldload: unexpected relocation type %d, "
263 "symbol index %d\n", rtype, symidx);
264 return (-1);
265 }
266 return(0);
267 }
268
269 int
elf_reloc(linker_file_t lf,Elf_Addr relocbase,const void * data,int type,elf_lookup_fn lookup)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, 0, lookup));
275 }
276
277 int
elf_reloc_local(linker_file_t lf,Elf_Addr relocbase,const void * data,int type,elf_lookup_fn lookup)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, 1, lookup));
283 }
284
285 int
elf_cpu_load_file(linker_file_t lf)286 elf_cpu_load_file(linker_file_t lf)
287 {
288
289 /*
290 * The pmap code does not do an icache sync upon establishing executable
291 * mappings in the kernel pmap. It's an optimization based on the fact
292 * that kernel memory allocations always have EXECUTABLE protection even
293 * when the memory isn't going to hold executable code. The only time
294 * kernel memory holding instructions does need a sync is after loading
295 * a kernel module, and that's when this function gets called.
296 *
297 * This syncs data and instruction caches after loading a module. We
298 * don't worry about the kernel itself (lf->id is 1) as locore.S did
299 * that on entry. Even if data cache maintenance was done by IO code,
300 * the relocation fixup process creates dirty cache entries that we must
301 * write back before doing icache sync. The instruction cache sync also
302 * invalidates the branch predictor cache on platforms that have one.
303 */
304 if (lf->id == 1)
305 return (0);
306 dcache_wb_pou((vm_offset_t)lf->address, (vm_size_t)lf->size);
307 icache_inv_all();
308
309 #if defined(DDB) || defined(KDTRACE_HOOKS) || defined(STACK)
310 /*
311 * Inform the stack(9) code of the new module, so it can acquire its
312 * per-module unwind data.
313 */
314 unwind_module_loaded(lf);
315 #endif
316
317 return (0);
318 }
319
320 int
elf_cpu_parse_dynamic(caddr_t loadbase __unused,Elf_Dyn * dynamic __unused)321 elf_cpu_parse_dynamic(caddr_t loadbase __unused, Elf_Dyn *dynamic __unused)
322 {
323
324 return (0);
325 }
326
327 int
elf_cpu_unload_file(linker_file_t lf)328 elf_cpu_unload_file(linker_file_t lf)
329 {
330
331 #if defined(DDB) || defined(KDTRACE_HOOKS) || defined(STACK)
332 /* Inform the stack(9) code that this module is gone. */
333 unwind_module_unloaded(lf);
334 #endif
335 return (0);
336 }
337