xref: /freebsd/sys/amd64/linux/linux_sysvec.c (revision b0d29bc47dba79f6f38e67eabadfb4b32ffd9390)
1 /*-
2  * Copyright (c) 2013 Dmitry Chagin
3  * Copyright (c) 2004 Tim J. Robbins
4  * Copyright (c) 2003 Peter Wemm
5  * Copyright (c) 2002 Doug Rabson
6  * Copyright (c) 1998-1999 Andrew Gallatin
7  * Copyright (c) 1994-1996 Søren Schmidt
8  * All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer
15  *    in this position and unchanged.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. The name of the author may not be used to endorse or promote products
20  *    derived from this software without specific prior written permission
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #define	__ELF_WORD_SIZE	64
38 
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/exec.h>
42 #include <sys/fcntl.h>
43 #include <sys/imgact.h>
44 #include <sys/imgact_elf.h>
45 #include <sys/kernel.h>
46 #include <sys/ktr.h>
47 #include <sys/lock.h>
48 #include <sys/malloc.h>
49 #include <sys/module.h>
50 #include <sys/mutex.h>
51 #include <sys/proc.h>
52 #include <sys/resourcevar.h>
53 #include <sys/signalvar.h>
54 #include <sys/syscallsubr.h>
55 #include <sys/sysctl.h>
56 #include <sys/sysent.h>
57 #include <sys/sysproto.h>
58 #include <sys/vnode.h>
59 #include <sys/eventhandler.h>
60 
61 #include <vm/vm.h>
62 #include <vm/pmap.h>
63 #include <vm/vm_extern.h>
64 #include <vm/vm_map.h>
65 #include <vm/vm_object.h>
66 #include <vm/vm_page.h>
67 #include <vm/vm_param.h>
68 
69 #include <machine/cpu.h>
70 #include <machine/md_var.h>
71 #include <machine/pcb.h>
72 #include <machine/specialreg.h>
73 #include <machine/trap.h>
74 
75 #include <amd64/linux/linux.h>
76 #include <amd64/linux/linux_proto.h>
77 #include <compat/linux/linux_emul.h>
78 #include <compat/linux/linux_ioctl.h>
79 #include <compat/linux/linux_mib.h>
80 #include <compat/linux/linux_misc.h>
81 #include <compat/linux/linux_signal.h>
82 #include <compat/linux/linux_sysproto.h>
83 #include <compat/linux/linux_util.h>
84 #include <compat/linux/linux_vdso.h>
85 
86 MODULE_VERSION(linux64, 1);
87 
88 const char *linux_kplatform;
89 static int linux_szsigcode;
90 static vm_object_t linux_shared_page_obj;
91 static char *linux_shared_page_mapping;
92 extern char _binary_linux_locore_o_start;
93 extern char _binary_linux_locore_o_end;
94 
95 extern struct sysent linux_sysent[LINUX_SYS_MAXSYSCALL];
96 
97 SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler);
98 
99 static int	linux_copyout_strings(struct image_params *imgp,
100 		    uintptr_t *stack_base);
101 static int	linux_fixup_elf(uintptr_t *stack_base,
102 		    struct image_params *iparams);
103 static bool	linux_trans_osrel(const Elf_Note *note, int32_t *osrel);
104 static void	linux_vdso_install(void *param);
105 static void	linux_vdso_deinstall(void *param);
106 static void	linux_set_syscall_retval(struct thread *td, int error);
107 static int	linux_fetch_syscall_args(struct thread *td);
108 static void	linux_exec_setregs(struct thread *td, struct image_params *imgp,
109 		    uintptr_t stack);
110 static int	linux_vsyscall(struct thread *td);
111 
112 #define LINUX_T_UNKNOWN  255
113 static int _bsd_to_linux_trapcode[] = {
114 	LINUX_T_UNKNOWN,	/* 0 */
115 	6,			/* 1  T_PRIVINFLT */
116 	LINUX_T_UNKNOWN,	/* 2 */
117 	3,			/* 3  T_BPTFLT */
118 	LINUX_T_UNKNOWN,	/* 4 */
119 	LINUX_T_UNKNOWN,	/* 5 */
120 	16,			/* 6  T_ARITHTRAP */
121 	254,			/* 7  T_ASTFLT */
122 	LINUX_T_UNKNOWN,	/* 8 */
123 	13,			/* 9  T_PROTFLT */
124 	1,			/* 10 T_TRCTRAP */
125 	LINUX_T_UNKNOWN,	/* 11 */
126 	14,			/* 12 T_PAGEFLT */
127 	LINUX_T_UNKNOWN,	/* 13 */
128 	17,			/* 14 T_ALIGNFLT */
129 	LINUX_T_UNKNOWN,	/* 15 */
130 	LINUX_T_UNKNOWN,	/* 16 */
131 	LINUX_T_UNKNOWN,	/* 17 */
132 	0,			/* 18 T_DIVIDE */
133 	2,			/* 19 T_NMI */
134 	4,			/* 20 T_OFLOW */
135 	5,			/* 21 T_BOUND */
136 	7,			/* 22 T_DNA */
137 	8,			/* 23 T_DOUBLEFLT */
138 	9,			/* 24 T_FPOPFLT */
139 	10,			/* 25 T_TSSFLT */
140 	11,			/* 26 T_SEGNPFLT */
141 	12,			/* 27 T_STKFLT */
142 	18,			/* 28 T_MCHK */
143 	19,			/* 29 T_XMMFLT */
144 	15			/* 30 T_RESERVED */
145 };
146 #define bsd_to_linux_trapcode(code) \
147     ((code)<nitems(_bsd_to_linux_trapcode)? \
148      _bsd_to_linux_trapcode[(code)]: \
149      LINUX_T_UNKNOWN)
150 
151 LINUX_VDSO_SYM_INTPTR(linux_rt_sigcode);
152 LINUX_VDSO_SYM_CHAR(linux_platform);
153 
154 /*
155  * If FreeBSD & Linux have a difference of opinion about what a trap
156  * means, deal with it here.
157  *
158  * MPSAFE
159  */
160 static int
161 linux_translate_traps(int signal, int trap_code)
162 {
163 
164 	if (signal != SIGBUS)
165 		return (signal);
166 	switch (trap_code) {
167 	case T_PROTFLT:
168 	case T_TSSFLT:
169 	case T_DOUBLEFLT:
170 	case T_PAGEFLT:
171 		return (SIGSEGV);
172 	default:
173 		return (signal);
174 	}
175 }
176 
177 static int
178 linux_fetch_syscall_args(struct thread *td)
179 {
180 	struct proc *p;
181 	struct trapframe *frame;
182 	struct syscall_args *sa;
183 
184 	p = td->td_proc;
185 	frame = td->td_frame;
186 	sa = &td->td_sa;
187 
188 	sa->args[0] = frame->tf_rdi;
189 	sa->args[1] = frame->tf_rsi;
190 	sa->args[2] = frame->tf_rdx;
191 	sa->args[3] = frame->tf_rcx;
192 	sa->args[4] = frame->tf_r8;
193 	sa->args[5] = frame->tf_r9;
194 	sa->code = frame->tf_rax;
195 
196 	if (sa->code >= p->p_sysent->sv_size)
197 		/* nosys */
198 		sa->callp = &p->p_sysent->sv_table[p->p_sysent->sv_size - 1];
199 	else
200 		sa->callp = &p->p_sysent->sv_table[sa->code];
201 	sa->narg = sa->callp->sy_narg;
202 
203 	td->td_retval[0] = 0;
204 	return (0);
205 }
206 
207 static void
208 linux_set_syscall_retval(struct thread *td, int error)
209 {
210 	struct trapframe *frame = td->td_frame;
211 
212 	/*
213 	 * On Linux only %rcx and %r11 values are not preserved across
214 	 * the syscall.  So, do not clobber %rdx and %r10.
215 	 */
216 	td->td_retval[1] = frame->tf_rdx;
217 	if (error != EJUSTRETURN)
218 		frame->tf_r10 = frame->tf_rcx;
219 
220 	cpu_set_syscall_retval(td, error);
221 
222 	 /* Restore all registers. */
223 	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
224 }
225 
226 static int
227 linux_copyout_auxargs(struct image_params *imgp, uintptr_t base)
228 {
229 	Elf_Auxargs *args;
230 	Elf_Auxinfo *argarray, *pos;
231 	struct proc *p;
232 	int error, issetugid;
233 
234 	p = imgp->proc;
235 	args = (Elf64_Auxargs *)imgp->auxargs;
236 	argarray = pos = malloc(LINUX_AT_COUNT * sizeof(*pos), M_TEMP,
237 	    M_WAITOK | M_ZERO);
238 
239 	issetugid = p->p_flag & P_SUGID ? 1 : 0;
240 	AUXARGS_ENTRY(pos, LINUX_AT_SYSINFO_EHDR,
241 	    imgp->proc->p_sysent->sv_shared_page_base);
242 	AUXARGS_ENTRY(pos, LINUX_AT_HWCAP, cpu_feature);
243 	AUXARGS_ENTRY(pos, LINUX_AT_CLKTCK, stclohz);
244 	AUXARGS_ENTRY(pos, AT_PHDR, args->phdr);
245 	AUXARGS_ENTRY(pos, AT_PHENT, args->phent);
246 	AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum);
247 	AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz);
248 	AUXARGS_ENTRY(pos, AT_BASE, args->base);
249 	AUXARGS_ENTRY(pos, AT_FLAGS, args->flags);
250 	AUXARGS_ENTRY(pos, AT_ENTRY, args->entry);
251 	AUXARGS_ENTRY(pos, AT_UID, imgp->proc->p_ucred->cr_ruid);
252 	AUXARGS_ENTRY(pos, AT_EUID, imgp->proc->p_ucred->cr_svuid);
253 	AUXARGS_ENTRY(pos, AT_GID, imgp->proc->p_ucred->cr_rgid);
254 	AUXARGS_ENTRY(pos, AT_EGID, imgp->proc->p_ucred->cr_svgid);
255 	AUXARGS_ENTRY(pos, LINUX_AT_SECURE, issetugid);
256 	AUXARGS_ENTRY(pos, LINUX_AT_PLATFORM, PTROUT(linux_platform));
257 	AUXARGS_ENTRY(pos, LINUX_AT_RANDOM, imgp->canary);
258 	if (imgp->execpathp != 0)
259 		AUXARGS_ENTRY(pos, LINUX_AT_EXECFN, imgp->execpathp);
260 	if (args->execfd != -1)
261 		AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd);
262 	AUXARGS_ENTRY(pos, AT_NULL, 0);
263 
264 	free(imgp->auxargs, M_TEMP);
265 	imgp->auxargs = NULL;
266 	KASSERT(pos - argarray <= LINUX_AT_COUNT, ("Too many auxargs"));
267 
268 	error = copyout(argarray, (void *)base,
269 	    sizeof(*argarray) * LINUX_AT_COUNT);
270 	free(argarray, M_TEMP);
271 	return (error);
272 }
273 
274 static int
275 linux_fixup_elf(uintptr_t *stack_base, struct image_params *imgp)
276 {
277 	Elf_Addr *base;
278 
279 	base = (Elf64_Addr *)*stack_base;
280 	base--;
281 	if (suword(base, (uint64_t)imgp->args->argc) == -1)
282 		return (EFAULT);
283 
284 	*stack_base = (uintptr_t)base;
285 	return (0);
286 }
287 
288 /*
289  * Copy strings out to the new process address space, constructing new arg
290  * and env vector tables. Return a pointer to the base so that it can be used
291  * as the initial stack pointer.
292  */
293 static int
294 linux_copyout_strings(struct image_params *imgp, uintptr_t *stack_base)
295 {
296 	int argc, envc, error;
297 	char **vectp;
298 	char *stringp;
299 	uintptr_t destp, ustringp;
300 	struct ps_strings *arginfo;
301 	char canary[LINUX_AT_RANDOM_LEN];
302 	size_t execpath_len;
303 	struct proc *p;
304 
305 	/* Calculate string base and vector table pointers. */
306 	if (imgp->execpath != NULL && imgp->auxargs != NULL)
307 		execpath_len = strlen(imgp->execpath) + 1;
308 	else
309 		execpath_len = 0;
310 
311 	p = imgp->proc;
312 	arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
313 	destp = (uintptr_t)arginfo;
314 
315 	if (execpath_len != 0) {
316 		destp -= execpath_len;
317 		destp = rounddown2(destp, sizeof(void *));
318 		imgp->execpathp = destp;
319 		error = copyout(imgp->execpath, (void *)destp, execpath_len);
320 		if (error != 0)
321 			return (error);
322 	}
323 
324 	/* Prepare the canary for SSP. */
325 	arc4rand(canary, sizeof(canary), 0);
326 	destp -= roundup(sizeof(canary), sizeof(void *));
327 	imgp->canary = destp;
328 	error = copyout(canary, (void *)destp, sizeof(canary));
329 	if (error != 0)
330 		return (error);
331 
332 	/* Allocate room for the argument and environment strings. */
333 	destp -= ARG_MAX - imgp->args->stringspace;
334 	destp = rounddown2(destp, sizeof(void *));
335 	ustringp = destp;
336 
337 	if (imgp->auxargs) {
338 		/*
339 		 * Allocate room on the stack for the ELF auxargs
340 		 * array.  It has LINUX_AT_COUNT entries.
341 		 */
342 		destp -= LINUX_AT_COUNT * sizeof(Elf64_Auxinfo);
343 		destp = rounddown2(destp, sizeof(void *));
344 	}
345 
346 	vectp = (char **)destp;
347 
348 	/*
349 	 * Allocate room for the argv[] and env vectors including the
350 	 * terminating NULL pointers.
351 	 */
352 	vectp -= imgp->args->argc + 1 + imgp->args->envc + 1;
353 
354 	/*
355 	 * Starting with 2.24, glibc depends on a 16-byte stack alignment.
356 	 * One "long argc" will be prepended later.
357 	 */
358 	vectp = (char **)((((uintptr_t)vectp + 8) & ~0xF) - 8);
359 
360 	/* vectp also becomes our initial stack base. */
361 	*stack_base = (uintptr_t)vectp;
362 
363 	stringp = imgp->args->begin_argv;
364 	argc = imgp->args->argc;
365 	envc = imgp->args->envc;
366 
367 	/* Copy out strings - arguments and environment. */
368 	error = copyout(stringp, (void *)ustringp,
369 	    ARG_MAX - imgp->args->stringspace);
370 	if (error != 0)
371 		return (error);
372 
373 	/* Fill in "ps_strings" struct for ps, w, etc. */
374 	if (suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp) != 0 ||
375 	    suword(&arginfo->ps_nargvstr, argc) != 0)
376 		return (EFAULT);
377 
378 	/* Fill in argument portion of vector table. */
379 	for (; argc > 0; --argc) {
380 		if (suword(vectp++, ustringp) != 0)
381 			return (EFAULT);
382 		while (*stringp++ != 0)
383 			ustringp++;
384 		ustringp++;
385 	}
386 
387 	/* A null vector table pointer separates the argp's from the envp's. */
388 	if (suword(vectp++, 0) != 0)
389 		return (EFAULT);
390 
391 	if (suword(&arginfo->ps_envstr, (long)(intptr_t)vectp) != 0 ||
392 	    suword(&arginfo->ps_nenvstr, envc) != 0)
393 		return (EFAULT);
394 
395 	/* Fill in environment portion of vector table. */
396 	for (; envc > 0; --envc) {
397 		if (suword(vectp++, ustringp) != 0)
398 			return (EFAULT);
399 		while (*stringp++ != 0)
400 			ustringp++;
401 		ustringp++;
402 	}
403 
404 	/* The end of the vector table is a null pointer. */
405 	if (suword(vectp, 0) != 0)
406 		return (EFAULT);
407 
408 	if (imgp->auxargs) {
409 		vectp++;
410 		error = imgp->sysent->sv_copyout_auxargs(imgp,
411 		    (uintptr_t)vectp);
412 		if (error != 0)
413 			return (error);
414 	}
415 
416 	return (0);
417 }
418 
419 /*
420  * Reset registers to default values on exec.
421  */
422 static void
423 linux_exec_setregs(struct thread *td, struct image_params *imgp,
424     uintptr_t stack)
425 {
426 	struct trapframe *regs;
427 	struct pcb *pcb;
428 	register_t saved_rflags;
429 
430 	regs = td->td_frame;
431 	pcb = td->td_pcb;
432 
433 	if (td->td_proc->p_md.md_ldt != NULL)
434 		user_ldt_free(td);
435 
436 	pcb->pcb_fsbase = 0;
437 	pcb->pcb_gsbase = 0;
438 	clear_pcb_flags(pcb, PCB_32BIT);
439 	pcb->pcb_initial_fpucw = __LINUX_NPXCW__;
440 	set_pcb_flags(pcb, PCB_FULL_IRET);
441 
442 	saved_rflags = regs->tf_rflags & PSL_T;
443 	bzero((char *)regs, sizeof(struct trapframe));
444 	regs->tf_rip = imgp->entry_addr;
445 	regs->tf_rsp = stack;
446 	regs->tf_rflags = PSL_USER | saved_rflags;
447 	regs->tf_ss = _udatasel;
448 	regs->tf_cs = _ucodesel;
449 	regs->tf_ds = _udatasel;
450 	regs->tf_es = _udatasel;
451 	regs->tf_fs = _ufssel;
452 	regs->tf_gs = _ugssel;
453 	regs->tf_flags = TF_HASSEGS;
454 
455 	/*
456 	 * Reset the hardware debug registers if they were in use.
457 	 * They won't have any meaning for the newly exec'd process.
458 	 */
459 	if (pcb->pcb_flags & PCB_DBREGS) {
460 		pcb->pcb_dr0 = 0;
461 		pcb->pcb_dr1 = 0;
462 		pcb->pcb_dr2 = 0;
463 		pcb->pcb_dr3 = 0;
464 		pcb->pcb_dr6 = 0;
465 		pcb->pcb_dr7 = 0;
466 		if (pcb == curpcb) {
467 			/*
468 			 * Clear the debug registers on the running
469 			 * CPU, otherwise they will end up affecting
470 			 * the next process we switch to.
471 			 */
472 			reset_dbregs();
473 		}
474 		clear_pcb_flags(pcb, PCB_DBREGS);
475 	}
476 
477 	/*
478 	 * Drop the FP state if we hold it, so that the process gets a
479 	 * clean FP state if it uses the FPU again.
480 	 */
481 	fpstate_drop(td);
482 }
483 
484 /*
485  * Copied from amd64/amd64/machdep.c
486  *
487  * XXX fpu state need? don't think so
488  */
489 int
490 linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
491 {
492 	struct proc *p;
493 	struct l_ucontext uc;
494 	struct l_sigcontext *context;
495 	struct trapframe *regs;
496 	unsigned long rflags;
497 	int error;
498 	ksiginfo_t ksi;
499 
500 	regs = td->td_frame;
501 	error = copyin((void *)regs->tf_rbx, &uc, sizeof(uc));
502 	if (error != 0)
503 		return (error);
504 
505 	p = td->td_proc;
506 	context = &uc.uc_mcontext;
507 	rflags = context->sc_rflags;
508 
509 	/*
510 	 * Don't allow users to change privileged or reserved flags.
511 	 */
512 	/*
513 	 * XXX do allow users to change the privileged flag PSL_RF.
514 	 * The cpu sets PSL_RF in tf_rflags for faults.  Debuggers
515 	 * should sometimes set it there too.  tf_rflags is kept in
516 	 * the signal context during signal handling and there is no
517 	 * other place to remember it, so the PSL_RF bit may be
518 	 * corrupted by the signal handler without us knowing.
519 	 * Corruption of the PSL_RF bit at worst causes one more or
520 	 * one less debugger trap, so allowing it is fairly harmless.
521 	 */
522 
523 #define RFLAG_SECURE(ef, oef)     ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0)
524 	if (!RFLAG_SECURE(rflags & ~PSL_RF, regs->tf_rflags & ~PSL_RF)) {
525 		printf("linux_rt_sigreturn: rflags = 0x%lx\n", rflags);
526 		return (EINVAL);
527 	}
528 
529 	/*
530 	 * Don't allow users to load a valid privileged %cs.  Let the
531 	 * hardware check for invalid selectors, excess privilege in
532 	 * other selectors, invalid %eip's and invalid %esp's.
533 	 */
534 #define CS_SECURE(cs)           (ISPL(cs) == SEL_UPL)
535 	if (!CS_SECURE(context->sc_cs)) {
536 		printf("linux_rt_sigreturn: cs = 0x%x\n", context->sc_cs);
537 		ksiginfo_init_trap(&ksi);
538 		ksi.ksi_signo = SIGBUS;
539 		ksi.ksi_code = BUS_OBJERR;
540 		ksi.ksi_trapno = T_PROTFLT;
541 		ksi.ksi_addr = (void *)regs->tf_rip;
542 		trapsignal(td, &ksi);
543 		return (EINVAL);
544 	}
545 
546 	PROC_LOCK(p);
547 	linux_to_bsd_sigset(&uc.uc_sigmask, &td->td_sigmask);
548 	SIG_CANTMASK(td->td_sigmask);
549 	signotify(td);
550 	PROC_UNLOCK(p);
551 
552 	regs->tf_rdi    = context->sc_rdi;
553 	regs->tf_rsi    = context->sc_rsi;
554 	regs->tf_rdx    = context->sc_rdx;
555 	regs->tf_rbp    = context->sc_rbp;
556 	regs->tf_rbx    = context->sc_rbx;
557 	regs->tf_rcx    = context->sc_rcx;
558 	regs->tf_rax    = context->sc_rax;
559 	regs->tf_rip    = context->sc_rip;
560 	regs->tf_rsp    = context->sc_rsp;
561 	regs->tf_r8     = context->sc_r8;
562 	regs->tf_r9     = context->sc_r9;
563 	regs->tf_r10    = context->sc_r10;
564 	regs->tf_r11    = context->sc_r11;
565 	regs->tf_r12    = context->sc_r12;
566 	regs->tf_r13    = context->sc_r13;
567 	regs->tf_r14    = context->sc_r14;
568 	regs->tf_r15    = context->sc_r15;
569 	regs->tf_cs     = context->sc_cs;
570 	regs->tf_err    = context->sc_err;
571 	regs->tf_rflags = rflags;
572 
573 	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
574 	return (EJUSTRETURN);
575 }
576 
577 /*
578  * copied from amd64/amd64/machdep.c
579  *
580  * Send an interrupt to process.
581  */
582 static void
583 linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
584 {
585 	struct l_rt_sigframe sf, *sfp;
586 	struct proc *p;
587 	struct thread *td;
588 	struct sigacts *psp;
589 	caddr_t sp;
590 	struct trapframe *regs;
591 	int sig, code;
592 	int oonstack;
593 
594 	td = curthread;
595 	p = td->td_proc;
596 	PROC_LOCK_ASSERT(p, MA_OWNED);
597 	sig = ksi->ksi_signo;
598 	psp = p->p_sigacts;
599 	code = ksi->ksi_code;
600 	mtx_assert(&psp->ps_mtx, MA_OWNED);
601 	regs = td->td_frame;
602 	oonstack = sigonstack(regs->tf_rsp);
603 
604 	LINUX_CTR4(rt_sendsig, "%p, %d, %p, %u",
605 	    catcher, sig, mask, code);
606 
607 	/* Allocate space for the signal handler context. */
608 	if ((td->td_pflags & TDP_ALTSTACK) != 0 && !oonstack &&
609 	    SIGISMEMBER(psp->ps_sigonstack, sig)) {
610 		sp = (caddr_t)td->td_sigstk.ss_sp + td->td_sigstk.ss_size -
611 		    sizeof(struct l_rt_sigframe);
612 	} else
613 		sp = (caddr_t)regs->tf_rsp - sizeof(struct l_rt_sigframe) - 128;
614 	/* Align to 16 bytes. */
615 	sfp = (struct l_rt_sigframe *)((unsigned long)sp & ~0xFul);
616 	mtx_unlock(&psp->ps_mtx);
617 
618 	/* Translate the signal. */
619 	sig = bsd_to_linux_signal(sig);
620 
621 	/* Save user context. */
622 	bzero(&sf, sizeof(sf));
623 	bsd_to_linux_sigset(mask, &sf.sf_sc.uc_sigmask);
624 	bsd_to_linux_sigset(mask, &sf.sf_sc.uc_mcontext.sc_mask);
625 
626 	sf.sf_sc.uc_stack.ss_sp = PTROUT(td->td_sigstk.ss_sp);
627 	sf.sf_sc.uc_stack.ss_size = td->td_sigstk.ss_size;
628 	sf.sf_sc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK)
629 	    ? ((oonstack) ? LINUX_SS_ONSTACK : 0) : LINUX_SS_DISABLE;
630 	PROC_UNLOCK(p);
631 
632 	sf.sf_sc.uc_mcontext.sc_rdi    = regs->tf_rdi;
633 	sf.sf_sc.uc_mcontext.sc_rsi    = regs->tf_rsi;
634 	sf.sf_sc.uc_mcontext.sc_rdx    = regs->tf_rdx;
635 	sf.sf_sc.uc_mcontext.sc_rbp    = regs->tf_rbp;
636 	sf.sf_sc.uc_mcontext.sc_rbx    = regs->tf_rbx;
637 	sf.sf_sc.uc_mcontext.sc_rcx    = regs->tf_rcx;
638 	sf.sf_sc.uc_mcontext.sc_rax    = regs->tf_rax;
639 	sf.sf_sc.uc_mcontext.sc_rip    = regs->tf_rip;
640 	sf.sf_sc.uc_mcontext.sc_rsp    = regs->tf_rsp;
641 	sf.sf_sc.uc_mcontext.sc_r8     = regs->tf_r8;
642 	sf.sf_sc.uc_mcontext.sc_r9     = regs->tf_r9;
643 	sf.sf_sc.uc_mcontext.sc_r10    = regs->tf_r10;
644 	sf.sf_sc.uc_mcontext.sc_r11    = regs->tf_r11;
645 	sf.sf_sc.uc_mcontext.sc_r12    = regs->tf_r12;
646 	sf.sf_sc.uc_mcontext.sc_r13    = regs->tf_r13;
647 	sf.sf_sc.uc_mcontext.sc_r14    = regs->tf_r14;
648 	sf.sf_sc.uc_mcontext.sc_r15    = regs->tf_r15;
649 	sf.sf_sc.uc_mcontext.sc_cs     = regs->tf_cs;
650 	sf.sf_sc.uc_mcontext.sc_rflags = regs->tf_rflags;
651 	sf.sf_sc.uc_mcontext.sc_err    = regs->tf_err;
652 	sf.sf_sc.uc_mcontext.sc_trapno = bsd_to_linux_trapcode(code);
653 	sf.sf_sc.uc_mcontext.sc_cr2    = (register_t)ksi->ksi_addr;
654 
655 	/* Build the argument list for the signal handler. */
656 	regs->tf_rdi = sig;			/* arg 1 in %rdi */
657 	regs->tf_rax = 0;
658 	regs->tf_rsi = (register_t)&sfp->sf_si;	/* arg 2 in %rsi */
659 	regs->tf_rdx = (register_t)&sfp->sf_sc;	/* arg 3 in %rdx */
660 
661 	sf.sf_handler = catcher;
662 	/* Fill in POSIX parts. */
663 	ksiginfo_to_lsiginfo(ksi, &sf.sf_si, sig);
664 
665 	/* Copy the sigframe out to the user's stack. */
666 	if (copyout(&sf, sfp, sizeof(*sfp)) != 0) {
667 		PROC_LOCK(p);
668 		sigexit(td, SIGILL);
669 	}
670 
671 	regs->tf_rsp = (long)sfp;
672 	regs->tf_rip = linux_rt_sigcode;
673 	regs->tf_rflags &= ~(PSL_T | PSL_D);
674 	regs->tf_cs = _ucodesel;
675 	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
676 	PROC_LOCK(p);
677 	mtx_lock(&psp->ps_mtx);
678 }
679 
680 #define	LINUX_VSYSCALL_START		(-10UL << 20)
681 #define	LINUX_VSYSCALL_SZ		1024
682 
683 const unsigned long linux_vsyscall_vector[] = {
684 	LINUX_SYS_gettimeofday,
685 	LINUX_SYS_linux_time,
686 				/* getcpu not implemented */
687 };
688 
689 static int
690 linux_vsyscall(struct thread *td)
691 {
692 	struct trapframe *frame;
693 	uint64_t retqaddr;
694 	int code, traced;
695 	int error;
696 
697 	frame = td->td_frame;
698 
699 	/* Check %rip for vsyscall area. */
700 	if (__predict_true(frame->tf_rip < LINUX_VSYSCALL_START))
701 		return (EINVAL);
702 	if ((frame->tf_rip & (LINUX_VSYSCALL_SZ - 1)) != 0)
703 		return (EINVAL);
704 	code = (frame->tf_rip - LINUX_VSYSCALL_START) / LINUX_VSYSCALL_SZ;
705 	if (code >= nitems(linux_vsyscall_vector))
706 		return (EINVAL);
707 
708 	/*
709 	 * vsyscall called as callq *(%rax), so we must
710 	 * use return address from %rsp and also fixup %rsp.
711 	 */
712 	error = copyin((void *)frame->tf_rsp, &retqaddr, sizeof(retqaddr));
713 	if (error)
714 		return (error);
715 
716 	frame->tf_rip = retqaddr;
717 	frame->tf_rax = linux_vsyscall_vector[code];
718 	frame->tf_rsp += 8;
719 
720 	traced = (frame->tf_flags & PSL_T);
721 
722 	amd64_syscall(td, traced);
723 
724 	return (0);
725 }
726 
727 struct sysentvec elf_linux_sysvec = {
728 	.sv_size	= LINUX_SYS_MAXSYSCALL,
729 	.sv_table	= linux_sysent,
730 	.sv_errsize	= ELAST + 1,
731 	.sv_errtbl	= linux_errtbl,
732 	.sv_transtrap	= linux_translate_traps,
733 	.sv_fixup	= linux_fixup_elf,
734 	.sv_sendsig	= linux_rt_sendsig,
735 	.sv_sigcode	= &_binary_linux_locore_o_start,
736 	.sv_szsigcode	= &linux_szsigcode,
737 	.sv_name	= "Linux ELF64",
738 	.sv_coredump	= elf64_coredump,
739 	.sv_imgact_try	= linux_exec_imgact_try,
740 	.sv_minsigstksz	= LINUX_MINSIGSTKSZ,
741 	.sv_minuser	= VM_MIN_ADDRESS,
742 	.sv_maxuser	= VM_MAXUSER_ADDRESS,
743 	.sv_usrstack	= USRSTACK,
744 	.sv_psstrings	= PS_STRINGS,
745 	.sv_stackprot	= VM_PROT_ALL,
746 	.sv_copyout_auxargs = linux_copyout_auxargs,
747 	.sv_copyout_strings = linux_copyout_strings,
748 	.sv_setregs	= linux_exec_setregs,
749 	.sv_fixlimit	= NULL,
750 	.sv_maxssiz	= NULL,
751 	.sv_flags	= SV_ABI_LINUX | SV_LP64 | SV_SHP,
752 	.sv_set_syscall_retval = linux_set_syscall_retval,
753 	.sv_fetch_syscall_args = linux_fetch_syscall_args,
754 	.sv_syscallnames = NULL,
755 	.sv_shared_page_base = SHAREDPAGE,
756 	.sv_shared_page_len = PAGE_SIZE,
757 	.sv_schedtail	= linux_schedtail,
758 	.sv_thread_detach = linux_thread_detach,
759 	.sv_trap	= linux_vsyscall,
760 };
761 
762 static void
763 linux_vdso_install(void *param)
764 {
765 
766 	amd64_lower_shared_page(&elf_linux_sysvec);
767 
768 	linux_szsigcode = (&_binary_linux_locore_o_end -
769 	    &_binary_linux_locore_o_start);
770 
771 	if (linux_szsigcode > elf_linux_sysvec.sv_shared_page_len)
772 		panic("Linux invalid vdso size\n");
773 
774 	__elfN(linux_vdso_fixup)(&elf_linux_sysvec);
775 
776 	linux_shared_page_obj = __elfN(linux_shared_page_init)
777 	    (&linux_shared_page_mapping);
778 
779 	__elfN(linux_vdso_reloc)(&elf_linux_sysvec);
780 
781 	bcopy(elf_linux_sysvec.sv_sigcode, linux_shared_page_mapping,
782 	    linux_szsigcode);
783 	elf_linux_sysvec.sv_shared_page_obj = linux_shared_page_obj;
784 
785 	linux_kplatform = linux_shared_page_mapping +
786 	    (linux_platform - (caddr_t)elf_linux_sysvec.sv_shared_page_base);
787 }
788 SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC, SI_ORDER_ANY,
789     linux_vdso_install, NULL);
790 
791 static void
792 linux_vdso_deinstall(void *param)
793 {
794 
795 	__elfN(linux_shared_page_fini)(linux_shared_page_obj);
796 }
797 SYSUNINIT(elf_linux_vdso_uninit, SI_SUB_EXEC, SI_ORDER_FIRST,
798     linux_vdso_deinstall, NULL);
799 
800 static char GNULINUX_ABI_VENDOR[] = "GNU";
801 static int GNULINUX_ABI_DESC = 0;
802 
803 static bool
804 linux_trans_osrel(const Elf_Note *note, int32_t *osrel)
805 {
806 	const Elf32_Word *desc;
807 	uintptr_t p;
808 
809 	p = (uintptr_t)(note + 1);
810 	p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
811 
812 	desc = (const Elf32_Word *)p;
813 	if (desc[0] != GNULINUX_ABI_DESC)
814 		return (false);
815 
816 	/*
817 	 * For Linux we encode osrel using the Linux convention of
818 	 * 	(version << 16) | (major << 8) | (minor)
819 	 * See macro in linux_mib.h
820 	 */
821 	*osrel = LINUX_KERNVER(desc[1], desc[2], desc[3]);
822 
823 	return (true);
824 }
825 
826 static Elf_Brandnote linux64_brandnote = {
827 	.hdr.n_namesz	= sizeof(GNULINUX_ABI_VENDOR),
828 	.hdr.n_descsz	= 16,
829 	.hdr.n_type	= 1,
830 	.vendor		= GNULINUX_ABI_VENDOR,
831 	.flags		= BN_TRANSLATE_OSREL,
832 	.trans_osrel	= linux_trans_osrel
833 };
834 
835 static Elf64_Brandinfo linux_glibc2brand = {
836 	.brand		= ELFOSABI_LINUX,
837 	.machine	= EM_X86_64,
838 	.compat_3_brand	= "Linux",
839 	.emul_path	= linux_emul_path,
840 	.interp_path	= "/lib64/ld-linux-x86-64.so.2",
841 	.sysvec		= &elf_linux_sysvec,
842 	.interp_newpath	= NULL,
843 	.brand_note	= &linux64_brandnote,
844 	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
845 };
846 
847 static Elf64_Brandinfo linux_glibc2brandshort = {
848 	.brand		= ELFOSABI_LINUX,
849 	.machine	= EM_X86_64,
850 	.compat_3_brand	= "Linux",
851 	.emul_path	= linux_emul_path,
852 	.interp_path	= "/lib64/ld-linux.so.2",
853 	.sysvec		= &elf_linux_sysvec,
854 	.interp_newpath	= NULL,
855 	.brand_note	= &linux64_brandnote,
856 	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
857 };
858 
859 static Elf64_Brandinfo linux_muslbrand = {
860 	.brand		= ELFOSABI_LINUX,
861 	.machine	= EM_X86_64,
862 	.compat_3_brand	= "Linux",
863 	.emul_path	= linux_emul_path,
864 	.interp_path	= "/lib/ld-musl-x86_64.so.1",
865 	.sysvec		= &elf_linux_sysvec,
866 	.interp_newpath	= NULL,
867 	.brand_note	= &linux64_brandnote,
868 	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
869 };
870 
871 Elf64_Brandinfo *linux_brandlist[] = {
872 	&linux_glibc2brand,
873 	&linux_glibc2brandshort,
874 	&linux_muslbrand,
875 	NULL
876 };
877 
878 static int
879 linux64_elf_modevent(module_t mod, int type, void *data)
880 {
881 	Elf64_Brandinfo **brandinfo;
882 	int error;
883 	struct linux_ioctl_handler **lihp;
884 
885 	error = 0;
886 
887 	switch(type) {
888 	case MOD_LOAD:
889 		for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
890 		     ++brandinfo)
891 			if (elf64_insert_brand_entry(*brandinfo) < 0)
892 				error = EINVAL;
893 		if (error == 0) {
894 			SET_FOREACH(lihp, linux_ioctl_handler_set)
895 				linux_ioctl_register_handler(*lihp);
896 			stclohz = (stathz ? stathz : hz);
897 			if (bootverbose)
898 				printf("Linux x86-64 ELF exec handler installed\n");
899 		} else
900 			printf("cannot insert Linux x86-64 ELF brand handler\n");
901 		break;
902 	case MOD_UNLOAD:
903 		for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
904 		     ++brandinfo)
905 			if (elf64_brand_inuse(*brandinfo))
906 				error = EBUSY;
907 		if (error == 0) {
908 			for (brandinfo = &linux_brandlist[0];
909 			     *brandinfo != NULL; ++brandinfo)
910 				if (elf64_remove_brand_entry(*brandinfo) < 0)
911 					error = EINVAL;
912 		}
913 		if (error == 0) {
914 			SET_FOREACH(lihp, linux_ioctl_handler_set)
915 				linux_ioctl_unregister_handler(*lihp);
916 			if (bootverbose)
917 				printf("Linux ELF exec handler removed\n");
918 		} else
919 			printf("Could not deinstall ELF interpreter entry\n");
920 		break;
921 	default:
922 		return (EOPNOTSUPP);
923 	}
924 	return (error);
925 }
926 
927 static moduledata_t linux64_elf_mod = {
928 	"linux64elf",
929 	linux64_elf_modevent,
930 	0
931 };
932 
933 DECLARE_MODULE_TIED(linux64elf, linux64_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY);
934 MODULE_DEPEND(linux64elf, linux_common, 1, 1, 1);
935 FEATURE(linux64, "Linux 64bit support");
936