xref: /freebsd/sys/powerpc/powerpc/elf32_machdep.c (revision 61e21613) 
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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/param.h>
29 #include <sys/kernel.h>
30 #include <sys/systm.h>
31 
32 #define __ELF_WORD_SIZE 32
33 
34 #include <sys/exec.h>
35 #include <sys/imgact.h>
36 #include <sys/malloc.h>
37 #include <sys/proc.h>
38 #include <sys/namei.h>
39 #include <sys/fcntl.h>
40 #include <sys/sysent.h>
41 #include <sys/imgact_elf.h>
42 #include <sys/jail.h>
43 #include <sys/reg.h>
44 #include <sys/smp.h>
45 #include <sys/syscall.h>
46 #include <sys/sysctl.h>
47 #include <sys/signalvar.h>
48 #include <sys/vnode.h>
49 #include <sys/linker.h>
50 
51 #include <vm/vm.h>
52 #include <vm/vm_param.h>
53 #include <vm/pmap.h>
54 #include <vm/vm_map.h>
55 
56 #include <machine/altivec.h>
57 #include <machine/cpu.h>
58 #include <machine/fpu.h>
59 #include <machine/elf.h>
60 #include <machine/md_var.h>
61 
62 #include <powerpc/powerpc/elf_common.c>
63 
64 #ifdef __powerpc64__
65 #include <compat/freebsd32/freebsd32_proto.h>
66 #include <compat/freebsd32/freebsd32_util.h>
67 
68 extern const char *freebsd32_syscallnames[];
69 static void ppc32_fixlimit(struct rlimit *rl, int which);
70 
71 static SYSCTL_NODE(_compat, OID_AUTO, ppc32, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
72     "32-bit mode");
73 
74 #define PPC32_MAXDSIZ (1024*1024*1024)
75 static u_long ppc32_maxdsiz = PPC32_MAXDSIZ;
76 SYSCTL_ULONG(_compat_ppc32, OID_AUTO, maxdsiz, CTLFLAG_RWTUN, &ppc32_maxdsiz,
77              0, "");
78 #define PPC32_MAXSSIZ (64*1024*1024)
79 u_long ppc32_maxssiz = PPC32_MAXSSIZ;
80 SYSCTL_ULONG(_compat_ppc32, OID_AUTO, maxssiz, CTLFLAG_RWTUN, &ppc32_maxssiz,
81              0, "");
82 #else
83 static void ppc32_runtime_resolve(void);
84 #endif
85 
86 struct sysentvec elf32_freebsd_sysvec = {
87 	.sv_size	= SYS_MAXSYSCALL,
88 #ifdef __powerpc64__
89 	.sv_table	= freebsd32_sysent,
90 #else
91 	.sv_table	= sysent,
92 #endif
93 	.sv_fixup	= __elfN(freebsd_fixup),
94 	.sv_copyout_auxargs = __elfN(powerpc_copyout_auxargs),
95 	.sv_sendsig	= sendsig,
96 	.sv_sigcode	= sigcode32,
97 	.sv_szsigcode	= &szsigcode32,
98 	.sv_name	= "FreeBSD ELF32",
99 	.sv_coredump	= __elfN(coredump),
100 	.sv_elf_core_osabi = ELFOSABI_FREEBSD,
101 	.sv_elf_core_abi_vendor = FREEBSD_ABI_VENDOR,
102 	.sv_elf_core_prepare_notes = __elfN(prepare_notes),
103 	.sv_minsigstksz	= MINSIGSTKSZ,
104 	.sv_minuser	= VM_MIN_ADDRESS,
105 	.sv_stackprot	= VM_PROT_ALL,
106 #ifdef __powerpc64__
107 	.sv_maxuser	= VM_MAXUSER_ADDRESS32,
108 	.sv_usrstack	= FREEBSD32_USRSTACK,
109 	.sv_psstrings	= FREEBSD32_PS_STRINGS,
110 	.sv_psstringssz	= sizeof(struct freebsd32_ps_strings),
111 	.sv_copyout_strings = freebsd32_copyout_strings,
112 	.sv_setregs	= ppc32_setregs,
113 	.sv_syscallnames = freebsd32_syscallnames,
114 	.sv_fixlimit	= ppc32_fixlimit,
115 #else
116 	.sv_maxuser	= VM_MAXUSER_ADDRESS,
117 	.sv_usrstack	= USRSTACK,
118 	.sv_psstrings	= PS_STRINGS,
119 	.sv_psstringssz	= sizeof(struct ps_strings),
120 	.sv_copyout_strings = exec_copyout_strings,
121 	.sv_setregs	= exec_setregs,
122 	.sv_syscallnames = syscallnames,
123 	.sv_fixlimit	= NULL,
124 #endif
125 	.sv_maxssiz	= NULL,
126 	.sv_flags	= SV_ABI_FREEBSD | SV_ILP32 | SV_SHP | SV_ASLR |
127 			    SV_TIMEKEEP | SV_RNG_SEED_VER | SV_SIGSYS,
128 	.sv_set_syscall_retval = cpu_set_syscall_retval,
129 	.sv_fetch_syscall_args = cpu_fetch_syscall_args,
130 	.sv_shared_page_base = FREEBSD32_SHAREDPAGE,
131 	.sv_shared_page_len = PAGE_SIZE,
132 	.sv_schedtail	= NULL,
133 	.sv_thread_detach = NULL,
134 	.sv_trap	= NULL,
135 	.sv_hwcap	= &cpu_features,
136 	.sv_hwcap2	= &cpu_features2,
137 	.sv_onexec_old	= exec_onexec_old,
138 	.sv_onexit	= exit_onexit,
139 	.sv_regset_begin = SET_BEGIN(__elfN(regset)),
140 	.sv_regset_end  = SET_LIMIT(__elfN(regset)),
141 };
142 INIT_SYSENTVEC(elf32_sysvec, &elf32_freebsd_sysvec);
143 
144 static Elf32_Brandinfo freebsd_brand_info = {
145 	.brand		= ELFOSABI_FREEBSD,
146 	.machine	= EM_PPC,
147 	.compat_3_brand	= "FreeBSD",
148 	.interp_path	= "/libexec/ld-elf.so.1",
149 	.sysvec		= &elf32_freebsd_sysvec,
150 #ifdef __powerpc64__
151 	.interp_newpath	= "/libexec/ld-elf32.so.1",
152 #else
153 	.interp_newpath	= NULL,
154 #endif
155 	.brand_note	= &elf32_freebsd_brandnote,
156 	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
157 };
158 
159 SYSINIT(elf32, SI_SUB_EXEC, SI_ORDER_FIRST,
160     (sysinit_cfunc_t) elf32_insert_brand_entry,
161     &freebsd_brand_info);
162 
163 static Elf32_Brandinfo freebsd_brand_oinfo = {
164 	.brand		= ELFOSABI_FREEBSD,
165 	.machine	= EM_PPC,
166 	.compat_3_brand	= "FreeBSD",
167 	.interp_path	= "/usr/libexec/ld-elf.so.1",
168 	.sysvec		= &elf32_freebsd_sysvec,
169 	.interp_newpath	= NULL,
170 	.brand_note	= &elf32_freebsd_brandnote,
171 	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
172 };
173 
174 SYSINIT(oelf32, SI_SUB_EXEC, SI_ORDER_ANY,
175 	(sysinit_cfunc_t) elf32_insert_brand_entry,
176 	&freebsd_brand_oinfo);
177 
178 void elf_reloc_self(Elf_Dyn *dynp, Elf_Addr relocbase);
179 
180 void
181 elf32_dump_thread(struct thread *td, void *dst, size_t *off)
182 {
183 	size_t len;
184 	struct pcb *pcb;
185 	uint64_t vshr[32];
186 	uint64_t *vsr_dw1;
187 	int vsr_idx;
188 
189 	len = 0;
190 	pcb = td->td_pcb;
191 
192 	if (pcb->pcb_flags & PCB_VEC) {
193 		save_vec_nodrop(td);
194 		if (dst != NULL) {
195 			len += elf32_populate_note(NT_PPC_VMX,
196 			    &pcb->pcb_vec, (char *)dst + len,
197 			    sizeof(pcb->pcb_vec), NULL);
198 		} else
199 			len += elf32_populate_note(NT_PPC_VMX, NULL, NULL,
200 			    sizeof(pcb->pcb_vec), NULL);
201 	}
202 
203 	if (pcb->pcb_flags & PCB_VSX) {
204 		save_fpu_nodrop(td);
205 		if (dst != NULL) {
206 			/*
207 			 * Doubleword 0 of VSR0-VSR31 overlap with FPR0-FPR31 and
208 			 * VSR32-VSR63 overlap with VR0-VR31, so we only copy
209 			 * the non-overlapping data, which is doubleword 1 of VSR0-VSR31.
210 			 */
211 			for (vsr_idx = 0; vsr_idx < nitems(vshr); vsr_idx++) {
212 				vsr_dw1 = (uint64_t *)&pcb->pcb_fpu.fpr[vsr_idx].vsr[2];
213 				vshr[vsr_idx] = *vsr_dw1;
214 			}
215 			len += elf32_populate_note(NT_PPC_VSX,
216 			    vshr, (char *)dst + len,
217 			    sizeof(vshr), NULL);
218 		} else
219 			len += elf32_populate_note(NT_PPC_VSX, NULL, NULL,
220 			    sizeof(vshr), NULL);
221 	}
222 
223 	*off = len;
224 }
225 
226 #ifndef __powerpc64__
227 bool
228 elf_is_ifunc_reloc(Elf_Size r_info)
229 {
230 
231 	return (ELF_R_TYPE(r_info) == R_PPC_IRELATIVE);
232 }
233 
234 /* Process one elf relocation with addend. */
235 static int
236 elf_reloc_internal(linker_file_t lf, Elf_Addr relocbase, const void *data,
237     int type, int local, elf_lookup_fn lookup)
238 {
239 	Elf_Addr *where;
240 	Elf_Half *hwhere;
241 	Elf_Addr addr;
242 	Elf_Addr addend, val;
243 	Elf_Word rtype, symidx;
244 	const Elf_Rela *rela;
245 	int error;
246 
247 	switch (type) {
248 	case ELF_RELOC_REL:
249 		panic("PPC only supports RELA relocations");
250 		break;
251 	case ELF_RELOC_RELA:
252 		rela = (const Elf_Rela *)data;
253 		where = (Elf_Addr *) ((uintptr_t)relocbase + rela->r_offset);
254 		hwhere = (Elf_Half *) ((uintptr_t)relocbase + rela->r_offset);
255 		addend = rela->r_addend;
256 		rtype = ELF_R_TYPE(rela->r_info);
257 		symidx = ELF_R_SYM(rela->r_info);
258 		break;
259 	default:
260 		panic("elf_reloc: unknown relocation mode %d\n", type);
261 	}
262 
263 	switch (rtype) {
264 	case R_PPC_NONE:
265 		break;
266 
267 	case R_PPC_ADDR32: /* word32 S + A */
268 		error = lookup(lf, symidx, 1, &addr);
269 		if (error != 0)
270 			return (-1);
271 		*where = elf_relocaddr(lf, addr + addend);
272 			break;
273 
274 	case R_PPC_ADDR16_LO: /* #lo(S) */
275 		error = lookup(lf, symidx, 1, &addr);
276 		if (error != 0)
277 			return (-1);
278 		/*
279 		 * addend values are sometimes relative to sections
280 		 * (i.e. .rodata) in rela, where in reality they
281 		 * are relative to relocbase. Detect this condition.
282 		 */
283 		if (addr > relocbase && addr <= (relocbase + addend))
284 			addr = relocbase;
285 		addr = elf_relocaddr(lf, addr + addend);
286 		*hwhere = addr & 0xffff;
287 		break;
288 
289 	case R_PPC_ADDR16_HA: /* #ha(S) */
290 		error = lookup(lf, symidx, 1, &addr);
291 		if (error != 0)
292 			return (-1);
293 		/*
294 		 * addend values are sometimes relative to sections
295 		 * (i.e. .rodata) in rela, where in reality they
296 		 * are relative to relocbase. Detect this condition.
297 		 */
298 		if (addr > relocbase && addr <= (relocbase + addend))
299 			addr = relocbase;
300 		addr = elf_relocaddr(lf, addr + addend);
301 		*hwhere = ((addr >> 16) + ((addr & 0x8000) ? 1 : 0))
302 		    & 0xffff;
303 		break;
304 
305 	case R_PPC_RELATIVE: /* word32 B + A */
306 		*where = elf_relocaddr(lf, relocbase + addend);
307 		break;
308 
309 	case R_PPC_JMP_SLOT: /* PLT jump slot entry */
310 		/*
311 		 * We currently only support Secure-PLT jump slots.
312 		 * Given that we reject BSS-PLT modules during load, we
313 		 * don't need to check again.
314 		 * The method we are using here is equivilent to
315 		 * LD_BIND_NOW.
316 		 */
317 		error = lookup(lf, symidx, 1, &addr);
318 		if (error != 0)
319 			return (-1);
320 		*where = elf_relocaddr(lf, addr + addend);
321 		break;
322 
323 	case R_PPC_IRELATIVE:
324 		addr = relocbase + addend;
325 		val = ((Elf32_Addr (*)(void))addr)();
326 		if (*where != val)
327 			*where = val;
328 		break;
329 
330 	default:
331 		printf("kldload: unexpected relocation type %d, "
332 		    "symbol index %d\n", (int)rtype, symidx);
333 		return (-1);
334 	}
335 	return (0);
336 }
337 
338 void
339 elf_reloc_self(Elf_Dyn *dynp, Elf_Addr relocbase)
340 {
341 	Elf_Rela *rela = NULL, *relalim;
342 	Elf_Addr relasz = 0;
343 	Elf_Addr *where;
344 
345 	/*
346 	 * Extract the rela/relasz values from the dynamic section
347 	 */
348 	for (; dynp->d_tag != DT_NULL; dynp++) {
349 		switch (dynp->d_tag) {
350 		case DT_RELA:
351 			rela = (Elf_Rela *)(relocbase+dynp->d_un.d_ptr);
352 			break;
353 		case DT_RELASZ:
354 			relasz = dynp->d_un.d_val;
355 			break;
356 		}
357 	}
358 
359 	/*
360 	 * Relocate these values
361 	 */
362 	relalim = (Elf_Rela *)((caddr_t)rela + relasz);
363 	for (; rela < relalim; rela++) {
364 		if (ELF_R_TYPE(rela->r_info) != R_PPC_RELATIVE)
365 			continue;
366 		where = (Elf_Addr *)(relocbase + rela->r_offset);
367 		*where = (Elf_Addr)(relocbase + rela->r_addend);
368 	}
369 }
370 
371 int
372 elf_reloc(linker_file_t lf, Elf_Addr relocbase, const void *data, int type,
373     elf_lookup_fn lookup)
374 {
375 
376 	return (elf_reloc_internal(lf, relocbase, data, type, 0, lookup));
377 }
378 
379 int
380 elf_reloc_local(linker_file_t lf, Elf_Addr relocbase, const void *data,
381     int type, elf_lookup_fn lookup)
382 {
383 
384 	return (elf_reloc_internal(lf, relocbase, data, type, 1, lookup));
385 }
386 
387 int
388 elf_cpu_load_file(linker_file_t lf)
389 {
390 
391 	/* Only sync the cache for non-kernel modules */
392 	if (lf->id != 1)
393 		__syncicache(lf->address, lf->size);
394 	return (0);
395 }
396 
397 int
398 elf_cpu_unload_file(linker_file_t lf __unused)
399 {
400 
401 	return (0);
402 }
403 
404 static void
405 ppc32_runtime_resolve(void)
406 {
407 
408 	/*
409 	 * Since we don't support lazy binding, panic immediately if anyone
410 	 * manages to call the runtime resolver.
411 	 */
412 	panic("kldload: Runtime resolver was called unexpectedly!");
413 }
414 
415 int
416 elf_cpu_parse_dynamic(caddr_t loadbase, Elf_Dyn *dynamic)
417 {
418 	Elf_Dyn *dp;
419 	bool has_plt = false;
420 	bool secure_plt = false;
421 	Elf_Addr *got;
422 
423 	for (dp = dynamic; dp->d_tag != DT_NULL; dp++) {
424 		switch (dp->d_tag) {
425 		case DT_PPC_GOT:
426 			secure_plt = true;
427 			got = (Elf_Addr *)(loadbase + dp->d_un.d_ptr);
428 			/* Install runtime resolver canary. */
429 			got[1] = (Elf_Addr)ppc32_runtime_resolve;
430 			got[2] = (Elf_Addr)0;
431 			break;
432 		case DT_PLTGOT:
433 			has_plt = true;
434 			break;
435 		}
436 	}
437 
438 	if (has_plt && !secure_plt) {
439 		printf("kldload: BSS-PLT modules are not supported.\n");
440 		return (-1);
441 	}
442 	return (0);
443 }
444 #endif
445 
446 #ifdef __powerpc64__
447 static void
448 ppc32_fixlimit(struct rlimit *rl, int which)
449 {
450 	switch (which) {
451 	case RLIMIT_DATA:
452 		if (ppc32_maxdsiz != 0) {
453 			if (rl->rlim_cur > ppc32_maxdsiz)
454 				rl->rlim_cur = ppc32_maxdsiz;
455 			if (rl->rlim_max > ppc32_maxdsiz)
456 				rl->rlim_max = ppc32_maxdsiz;
457 		}
458 		break;
459 	case RLIMIT_STACK:
460 		if (ppc32_maxssiz != 0) {
461 			if (rl->rlim_cur > ppc32_maxssiz)
462 				rl->rlim_cur = ppc32_maxssiz;
463 			if (rl->rlim_max > ppc32_maxssiz)
464 				rl->rlim_max = ppc32_maxssiz;
465 		}
466 		break;
467 	}
468 }
469 #endif
470