xref: /freebsd/sys/amd64/linux/linux_sysvec.c (revision cddbc3b40812213ff00041f79174cac0be360a2a)
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_futex.h>
79 #include <compat/linux/linux_ioctl.h>
80 #include <compat/linux/linux_mib.h>
81 #include <compat/linux/linux_misc.h>
82 #include <compat/linux/linux_signal.h>
83 #include <compat/linux/linux_sysproto.h>
84 #include <compat/linux/linux_util.h>
85 #include <compat/linux/linux_vdso.h>
86 
87 MODULE_VERSION(linux64, 1);
88 
89 #if defined(DEBUG)
90 SYSCTL_PROC(_compat_linux, OID_AUTO, debug,
91 	    CTLTYPE_STRING | CTLFLAG_RW,
92 	    0, 0, linux_sysctl_debug, "A",
93 	    "Linux 64 debugging control");
94 #endif
95 
96 /*
97  * Allow the sendsig functions to use the ldebug() facility even though they
98  * are not syscalls themselves.  Map them to syscall 0.  This is slightly less
99  * bogus than using ldebug(sigreturn).
100  */
101 #define	LINUX_SYS_linux_rt_sendsig	0
102 
103 const char *linux_kplatform;
104 static int linux_szsigcode;
105 static vm_object_t linux_shared_page_obj;
106 static char *linux_shared_page_mapping;
107 extern char _binary_linux_locore_o_start;
108 extern char _binary_linux_locore_o_end;
109 
110 extern struct sysent linux_sysent[LINUX_SYS_MAXSYSCALL];
111 
112 SET_DECLARE(linux_ioctl_handler_set, struct linux_ioctl_handler);
113 
114 static register_t * linux_copyout_strings(struct image_params *imgp);
115 static int	linux_fixup_elf(register_t **stack_base,
116 		    struct image_params *iparams);
117 static bool	linux_trans_osrel(const Elf_Note *note, int32_t *osrel);
118 static void	linux_vdso_install(void *param);
119 static void	linux_vdso_deinstall(void *param);
120 static void	linux_set_syscall_retval(struct thread *td, int error);
121 static int	linux_fetch_syscall_args(struct thread *td);
122 static void	linux_exec_setregs(struct thread *td, struct image_params *imgp,
123 		    u_long stack);
124 static int	linux_vsyscall(struct thread *td);
125 
126 #define LINUX_T_UNKNOWN  255
127 static int _bsd_to_linux_trapcode[] = {
128 	LINUX_T_UNKNOWN,	/* 0 */
129 	6,			/* 1  T_PRIVINFLT */
130 	LINUX_T_UNKNOWN,	/* 2 */
131 	3,			/* 3  T_BPTFLT */
132 	LINUX_T_UNKNOWN,	/* 4 */
133 	LINUX_T_UNKNOWN,	/* 5 */
134 	16,			/* 6  T_ARITHTRAP */
135 	254,			/* 7  T_ASTFLT */
136 	LINUX_T_UNKNOWN,	/* 8 */
137 	13,			/* 9  T_PROTFLT */
138 	1,			/* 10 T_TRCTRAP */
139 	LINUX_T_UNKNOWN,	/* 11 */
140 	14,			/* 12 T_PAGEFLT */
141 	LINUX_T_UNKNOWN,	/* 13 */
142 	17,			/* 14 T_ALIGNFLT */
143 	LINUX_T_UNKNOWN,	/* 15 */
144 	LINUX_T_UNKNOWN,	/* 16 */
145 	LINUX_T_UNKNOWN,	/* 17 */
146 	0,			/* 18 T_DIVIDE */
147 	2,			/* 19 T_NMI */
148 	4,			/* 20 T_OFLOW */
149 	5,			/* 21 T_BOUND */
150 	7,			/* 22 T_DNA */
151 	8,			/* 23 T_DOUBLEFLT */
152 	9,			/* 24 T_FPOPFLT */
153 	10,			/* 25 T_TSSFLT */
154 	11,			/* 26 T_SEGNPFLT */
155 	12,			/* 27 T_STKFLT */
156 	18,			/* 28 T_MCHK */
157 	19,			/* 29 T_XMMFLT */
158 	15			/* 30 T_RESERVED */
159 };
160 #define bsd_to_linux_trapcode(code) \
161     ((code)<nitems(_bsd_to_linux_trapcode)? \
162      _bsd_to_linux_trapcode[(code)]: \
163      LINUX_T_UNKNOWN)
164 
165 LINUX_VDSO_SYM_INTPTR(linux_rt_sigcode);
166 LINUX_VDSO_SYM_CHAR(linux_platform);
167 
168 /*
169  * If FreeBSD & Linux have a difference of opinion about what a trap
170  * means, deal with it here.
171  *
172  * MPSAFE
173  */
174 static int
175 linux_translate_traps(int signal, int trap_code)
176 {
177 
178 	if (signal != SIGBUS)
179 		return (signal);
180 	switch (trap_code) {
181 	case T_PROTFLT:
182 	case T_TSSFLT:
183 	case T_DOUBLEFLT:
184 	case T_PAGEFLT:
185 		return (SIGSEGV);
186 	default:
187 		return (signal);
188 	}
189 }
190 
191 static int
192 linux_fetch_syscall_args(struct thread *td)
193 {
194 	struct proc *p;
195 	struct trapframe *frame;
196 	struct syscall_args *sa;
197 
198 	p = td->td_proc;
199 	frame = td->td_frame;
200 	sa = &td->td_sa;
201 
202 	sa->args[0] = frame->tf_rdi;
203 	sa->args[1] = frame->tf_rsi;
204 	sa->args[2] = frame->tf_rdx;
205 	sa->args[3] = frame->tf_rcx;
206 	sa->args[4] = frame->tf_r8;
207 	sa->args[5] = frame->tf_r9;
208 	sa->code = frame->tf_rax;
209 
210 	if (sa->code >= p->p_sysent->sv_size)
211 		/* nosys */
212 		sa->callp = &p->p_sysent->sv_table[p->p_sysent->sv_size - 1];
213 	else
214 		sa->callp = &p->p_sysent->sv_table[sa->code];
215 	sa->narg = sa->callp->sy_narg;
216 
217 	td->td_retval[0] = 0;
218 	return (0);
219 }
220 
221 static void
222 linux_set_syscall_retval(struct thread *td, int error)
223 {
224 	struct trapframe *frame = td->td_frame;
225 
226 	/*
227 	 * On Linux only %rcx and %r11 values are not preserved across
228 	 * the syscall.  So, do not clobber %rdx and %r10.
229 	 */
230 	td->td_retval[1] = frame->tf_rdx;
231 	if (error != EJUSTRETURN)
232 		frame->tf_r10 = frame->tf_rcx;
233 
234 	cpu_set_syscall_retval(td, error);
235 
236 	 /* Restore all registers. */
237 	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
238 }
239 
240 static int
241 linux_fixup_elf(register_t **stack_base, struct image_params *imgp)
242 {
243 	Elf_Auxargs *args;
244 	Elf_Auxinfo *argarray, *pos;
245 	Elf_Addr *auxbase, *base;
246 	struct ps_strings *arginfo;
247 	struct proc *p;
248 	int error, issetugid;
249 
250 	p = imgp->proc;
251 	arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
252 
253 	KASSERT(curthread->td_proc == imgp->proc,
254 	    ("unsafe linux_fixup_elf(), should be curproc"));
255 	base = (Elf64_Addr *)*stack_base;
256 	args = (Elf64_Auxargs *)imgp->auxargs;
257 	auxbase = base + imgp->args->argc + 1 + imgp->args->envc + 1;
258 	argarray = pos = malloc(LINUX_AT_COUNT * sizeof(*pos), M_TEMP,
259 	    M_WAITOK | M_ZERO);
260 
261 	issetugid = p->p_flag & P_SUGID ? 1 : 0;
262 	AUXARGS_ENTRY(pos, LINUX_AT_SYSINFO_EHDR,
263 	    imgp->proc->p_sysent->sv_shared_page_base);
264 	AUXARGS_ENTRY(pos, LINUX_AT_HWCAP, cpu_feature);
265 	AUXARGS_ENTRY(pos, LINUX_AT_CLKTCK, stclohz);
266 	AUXARGS_ENTRY(pos, AT_PHDR, args->phdr);
267 	AUXARGS_ENTRY(pos, AT_PHENT, args->phent);
268 	AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum);
269 	AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz);
270 	AUXARGS_ENTRY(pos, AT_BASE, args->base);
271 	AUXARGS_ENTRY(pos, AT_FLAGS, args->flags);
272 	AUXARGS_ENTRY(pos, AT_ENTRY, args->entry);
273 	AUXARGS_ENTRY(pos, AT_UID, imgp->proc->p_ucred->cr_ruid);
274 	AUXARGS_ENTRY(pos, AT_EUID, imgp->proc->p_ucred->cr_svuid);
275 	AUXARGS_ENTRY(pos, AT_GID, imgp->proc->p_ucred->cr_rgid);
276 	AUXARGS_ENTRY(pos, AT_EGID, imgp->proc->p_ucred->cr_svgid);
277 	AUXARGS_ENTRY(pos, LINUX_AT_SECURE, issetugid);
278 	AUXARGS_ENTRY(pos, LINUX_AT_PLATFORM, PTROUT(linux_platform));
279 	AUXARGS_ENTRY(pos, LINUX_AT_RANDOM, imgp->canary);
280 	if (imgp->execpathp != 0)
281 		AUXARGS_ENTRY(pos, LINUX_AT_EXECFN, imgp->execpathp);
282 	if (args->execfd != -1)
283 		AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd);
284 	AUXARGS_ENTRY(pos, AT_NULL, 0);
285 	free(imgp->auxargs, M_TEMP);
286 	imgp->auxargs = NULL;
287 	KASSERT(pos - argarray <= LINUX_AT_COUNT, ("Too many auxargs"));
288 
289 	error = copyout(argarray, auxbase, sizeof(*argarray) * LINUX_AT_COUNT);
290 	free(argarray, M_TEMP);
291 	if (error != 0)
292 		return (error);
293 
294 	base--;
295 	if (suword(base, (uint64_t)imgp->args->argc) == -1)
296 		return (EFAULT);
297 
298 	*stack_base = (register_t *)base;
299 	return (0);
300 }
301 
302 /*
303  * Copy strings out to the new process address space, constructing new arg
304  * and env vector tables. Return a pointer to the base so that it can be used
305  * as the initial stack pointer.
306  */
307 static register_t *
308 linux_copyout_strings(struct image_params *imgp)
309 {
310 	int argc, envc;
311 	char **vectp;
312 	char *stringp, *destp;
313 	register_t *stack_base;
314 	struct ps_strings *arginfo;
315 	char canary[LINUX_AT_RANDOM_LEN];
316 	size_t execpath_len;
317 	struct proc *p;
318 
319 	/* Calculate string base and vector table pointers. */
320 	if (imgp->execpath != NULL && imgp->auxargs != NULL)
321 		execpath_len = strlen(imgp->execpath) + 1;
322 	else
323 		execpath_len = 0;
324 
325 	p = imgp->proc;
326 	arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings;
327 	destp = (caddr_t)arginfo - SPARE_USRSPACE -
328 	    roundup(sizeof(canary), sizeof(char *)) -
329 	    roundup(execpath_len, sizeof(char *)) -
330 	    roundup(ARG_MAX - imgp->args->stringspace, sizeof(char *));
331 
332 	if (execpath_len != 0) {
333 		imgp->execpathp = (uintptr_t)arginfo - execpath_len;
334 		copyout(imgp->execpath, (void *)imgp->execpathp, execpath_len);
335 	}
336 
337 	/* Prepare the canary for SSP. */
338 	arc4rand(canary, sizeof(canary), 0);
339 	imgp->canary = (uintptr_t)arginfo -
340 	    roundup(execpath_len, sizeof(char *)) -
341 	    roundup(sizeof(canary), sizeof(char *));
342 	copyout(canary, (void *)imgp->canary, sizeof(canary));
343 
344 	vectp = (char **)destp;
345 	if (imgp->auxargs) {
346 		/*
347 		 * Allocate room on the stack for the ELF auxargs
348 		 * array.  It has LINUX_AT_COUNT entries.
349 		 */
350 		vectp -= howmany(LINUX_AT_COUNT * sizeof(Elf64_Auxinfo),
351 		    sizeof(*vectp));
352 	}
353 
354 	/*
355 	 * Allocate room for the argv[] and env vectors including the
356 	 * terminating NULL pointers.
357 	 */
358 	vectp -= imgp->args->argc + 1 + imgp->args->envc + 1;
359 
360 	/* vectp also becomes our initial stack base. */
361 	stack_base = (register_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 	copyout(stringp, destp, ARG_MAX - imgp->args->stringspace);
369 
370 	/* Fill in "ps_strings" struct for ps, w, etc. */
371 	suword(&arginfo->ps_argvstr, (long)(intptr_t)vectp);
372 	suword(&arginfo->ps_nargvstr, argc);
373 
374 	/* Fill in argument portion of vector table. */
375 	for (; argc > 0; --argc) {
376 		suword(vectp++, (long)(intptr_t)destp);
377 		while (*stringp++ != 0)
378 			destp++;
379 		destp++;
380 	}
381 
382 	/* A null vector table pointer separates the argp's from the envp's. */
383 	suword(vectp++, 0);
384 
385 	suword(&arginfo->ps_envstr, (long)(intptr_t)vectp);
386 	suword(&arginfo->ps_nenvstr, envc);
387 
388 	/* Fill in environment portion of vector table. */
389 	for (; envc > 0; --envc) {
390 		suword(vectp++, (long)(intptr_t)destp);
391 		while (*stringp++ != 0)
392 			destp++;
393 		destp++;
394 	}
395 
396 	/* The end of the vector table is a null pointer. */
397 	suword(vectp, 0);
398 	return (stack_base);
399 }
400 
401 /*
402  * Reset registers to default values on exec.
403  */
404 static void
405 linux_exec_setregs(struct thread *td, struct image_params *imgp, u_long stack)
406 {
407 	struct trapframe *regs;
408 	struct pcb *pcb;
409 	register_t saved_rflags;
410 
411 	regs = td->td_frame;
412 	pcb = td->td_pcb;
413 
414 	if (td->td_proc->p_md.md_ldt != NULL)
415 		user_ldt_free(td);
416 
417 	pcb->pcb_fsbase = 0;
418 	pcb->pcb_gsbase = 0;
419 	clear_pcb_flags(pcb, PCB_32BIT);
420 	pcb->pcb_initial_fpucw = __LINUX_NPXCW__;
421 	set_pcb_flags(pcb, PCB_FULL_IRET);
422 
423 	saved_rflags = regs->tf_rflags & PSL_T;
424 	bzero((char *)regs, sizeof(struct trapframe));
425 	regs->tf_rip = imgp->entry_addr;
426 	regs->tf_rsp = stack;
427 	regs->tf_rflags = PSL_USER | saved_rflags;
428 	regs->tf_ss = _udatasel;
429 	regs->tf_cs = _ucodesel;
430 	regs->tf_ds = _udatasel;
431 	regs->tf_es = _udatasel;
432 	regs->tf_fs = _ufssel;
433 	regs->tf_gs = _ugssel;
434 	regs->tf_flags = TF_HASSEGS;
435 
436 	/*
437 	 * Reset the hardware debug registers if they were in use.
438 	 * They won't have any meaning for the newly exec'd process.
439 	 */
440 	if (pcb->pcb_flags & PCB_DBREGS) {
441 		pcb->pcb_dr0 = 0;
442 		pcb->pcb_dr1 = 0;
443 		pcb->pcb_dr2 = 0;
444 		pcb->pcb_dr3 = 0;
445 		pcb->pcb_dr6 = 0;
446 		pcb->pcb_dr7 = 0;
447 		if (pcb == curpcb) {
448 			/*
449 			 * Clear the debug registers on the running
450 			 * CPU, otherwise they will end up affecting
451 			 * the next process we switch to.
452 			 */
453 			reset_dbregs();
454 		}
455 		clear_pcb_flags(pcb, PCB_DBREGS);
456 	}
457 
458 	/*
459 	 * Drop the FP state if we hold it, so that the process gets a
460 	 * clean FP state if it uses the FPU again.
461 	 */
462 	fpstate_drop(td);
463 }
464 
465 /*
466  * Copied from amd64/amd64/machdep.c
467  *
468  * XXX fpu state need? don't think so
469  */
470 int
471 linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
472 {
473 	struct proc *p;
474 	struct l_ucontext uc;
475 	struct l_sigcontext *context;
476 	struct trapframe *regs;
477 	unsigned long rflags;
478 	int error;
479 	ksiginfo_t ksi;
480 
481 	regs = td->td_frame;
482 	error = copyin((void *)regs->tf_rbx, &uc, sizeof(uc));
483 	if (error != 0)
484 		return (error);
485 
486 	p = td->td_proc;
487 	context = &uc.uc_mcontext;
488 	rflags = context->sc_rflags;
489 
490 	/*
491 	 * Don't allow users to change privileged or reserved flags.
492 	 */
493 	/*
494 	 * XXX do allow users to change the privileged flag PSL_RF.
495 	 * The cpu sets PSL_RF in tf_rflags for faults.  Debuggers
496 	 * should sometimes set it there too.  tf_rflags is kept in
497 	 * the signal context during signal handling and there is no
498 	 * other place to remember it, so the PSL_RF bit may be
499 	 * corrupted by the signal handler without us knowing.
500 	 * Corruption of the PSL_RF bit at worst causes one more or
501 	 * one less debugger trap, so allowing it is fairly harmless.
502 	 */
503 
504 #define RFLAG_SECURE(ef, oef)     ((((ef) ^ (oef)) & ~PSL_USERCHANGE) == 0)
505 	if (!RFLAG_SECURE(rflags & ~PSL_RF, regs->tf_rflags & ~PSL_RF)) {
506 		printf("linux_rt_sigreturn: rflags = 0x%lx\n", rflags);
507 		return (EINVAL);
508 	}
509 
510 	/*
511 	 * Don't allow users to load a valid privileged %cs.  Let the
512 	 * hardware check for invalid selectors, excess privilege in
513 	 * other selectors, invalid %eip's and invalid %esp's.
514 	 */
515 #define CS_SECURE(cs)           (ISPL(cs) == SEL_UPL)
516 	if (!CS_SECURE(context->sc_cs)) {
517 		printf("linux_rt_sigreturn: cs = 0x%x\n", context->sc_cs);
518 		ksiginfo_init_trap(&ksi);
519 		ksi.ksi_signo = SIGBUS;
520 		ksi.ksi_code = BUS_OBJERR;
521 		ksi.ksi_trapno = T_PROTFLT;
522 		ksi.ksi_addr = (void *)regs->tf_rip;
523 		trapsignal(td, &ksi);
524 		return (EINVAL);
525 	}
526 
527 	PROC_LOCK(p);
528 	linux_to_bsd_sigset(&uc.uc_sigmask, &td->td_sigmask);
529 	SIG_CANTMASK(td->td_sigmask);
530 	signotify(td);
531 	PROC_UNLOCK(p);
532 
533 	regs->tf_rdi    = context->sc_rdi;
534 	regs->tf_rsi    = context->sc_rsi;
535 	regs->tf_rdx    = context->sc_rdx;
536 	regs->tf_rbp    = context->sc_rbp;
537 	regs->tf_rbx    = context->sc_rbx;
538 	regs->tf_rcx    = context->sc_rcx;
539 	regs->tf_rax    = context->sc_rax;
540 	regs->tf_rip    = context->sc_rip;
541 	regs->tf_rsp    = context->sc_rsp;
542 	regs->tf_r8     = context->sc_r8;
543 	regs->tf_r9     = context->sc_r9;
544 	regs->tf_r10    = context->sc_r10;
545 	regs->tf_r11    = context->sc_r11;
546 	regs->tf_r12    = context->sc_r12;
547 	regs->tf_r13    = context->sc_r13;
548 	regs->tf_r14    = context->sc_r14;
549 	regs->tf_r15    = context->sc_r15;
550 	regs->tf_cs     = context->sc_cs;
551 	regs->tf_err    = context->sc_err;
552 	regs->tf_rflags = rflags;
553 
554 	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
555 	return (EJUSTRETURN);
556 }
557 
558 /*
559  * copied from amd64/amd64/machdep.c
560  *
561  * Send an interrupt to process.
562  */
563 static void
564 linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
565 {
566 	struct l_rt_sigframe sf, *sfp;
567 	struct proc *p;
568 	struct thread *td;
569 	struct sigacts *psp;
570 	caddr_t sp;
571 	struct trapframe *regs;
572 	int sig, code;
573 	int oonstack;
574 
575 	td = curthread;
576 	p = td->td_proc;
577 	PROC_LOCK_ASSERT(p, MA_OWNED);
578 	sig = ksi->ksi_signo;
579 	psp = p->p_sigacts;
580 	code = ksi->ksi_code;
581 	mtx_assert(&psp->ps_mtx, MA_OWNED);
582 	regs = td->td_frame;
583 	oonstack = sigonstack(regs->tf_rsp);
584 
585 	LINUX_CTR4(rt_sendsig, "%p, %d, %p, %u",
586 	    catcher, sig, mask, code);
587 
588 	/* Allocate space for the signal handler context. */
589 	if ((td->td_pflags & TDP_ALTSTACK) != 0 && !oonstack &&
590 	    SIGISMEMBER(psp->ps_sigonstack, sig)) {
591 		sp = (caddr_t)td->td_sigstk.ss_sp + td->td_sigstk.ss_size -
592 		    sizeof(struct l_rt_sigframe);
593 	} else
594 		sp = (caddr_t)regs->tf_rsp - sizeof(struct l_rt_sigframe) - 128;
595 	/* Align to 16 bytes. */
596 	sfp = (struct l_rt_sigframe *)((unsigned long)sp & ~0xFul);
597 	mtx_unlock(&psp->ps_mtx);
598 
599 	/* Translate the signal. */
600 	sig = bsd_to_linux_signal(sig);
601 
602 	/* Save user context. */
603 	bzero(&sf, sizeof(sf));
604 	bsd_to_linux_sigset(mask, &sf.sf_sc.uc_sigmask);
605 	bsd_to_linux_sigset(mask, &sf.sf_sc.uc_mcontext.sc_mask);
606 
607 	sf.sf_sc.uc_stack.ss_sp = PTROUT(td->td_sigstk.ss_sp);
608 	sf.sf_sc.uc_stack.ss_size = td->td_sigstk.ss_size;
609 	sf.sf_sc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK)
610 	    ? ((oonstack) ? LINUX_SS_ONSTACK : 0) : LINUX_SS_DISABLE;
611 	PROC_UNLOCK(p);
612 
613 	sf.sf_sc.uc_mcontext.sc_rdi    = regs->tf_rdi;
614 	sf.sf_sc.uc_mcontext.sc_rsi    = regs->tf_rsi;
615 	sf.sf_sc.uc_mcontext.sc_rdx    = regs->tf_rdx;
616 	sf.sf_sc.uc_mcontext.sc_rbp    = regs->tf_rbp;
617 	sf.sf_sc.uc_mcontext.sc_rbx    = regs->tf_rbx;
618 	sf.sf_sc.uc_mcontext.sc_rcx    = regs->tf_rcx;
619 	sf.sf_sc.uc_mcontext.sc_rax    = regs->tf_rax;
620 	sf.sf_sc.uc_mcontext.sc_rip    = regs->tf_rip;
621 	sf.sf_sc.uc_mcontext.sc_rsp    = regs->tf_rsp;
622 	sf.sf_sc.uc_mcontext.sc_r8     = regs->tf_r8;
623 	sf.sf_sc.uc_mcontext.sc_r9     = regs->tf_r9;
624 	sf.sf_sc.uc_mcontext.sc_r10    = regs->tf_r10;
625 	sf.sf_sc.uc_mcontext.sc_r11    = regs->tf_r11;
626 	sf.sf_sc.uc_mcontext.sc_r12    = regs->tf_r12;
627 	sf.sf_sc.uc_mcontext.sc_r13    = regs->tf_r13;
628 	sf.sf_sc.uc_mcontext.sc_r14    = regs->tf_r14;
629 	sf.sf_sc.uc_mcontext.sc_r15    = regs->tf_r15;
630 	sf.sf_sc.uc_mcontext.sc_cs     = regs->tf_cs;
631 	sf.sf_sc.uc_mcontext.sc_rflags = regs->tf_rflags;
632 	sf.sf_sc.uc_mcontext.sc_err    = regs->tf_err;
633 	sf.sf_sc.uc_mcontext.sc_trapno = bsd_to_linux_trapcode(code);
634 	sf.sf_sc.uc_mcontext.sc_cr2    = (register_t)ksi->ksi_addr;
635 
636 	/* Build the argument list for the signal handler. */
637 	regs->tf_rdi = sig;			/* arg 1 in %rdi */
638 	regs->tf_rax = 0;
639 	regs->tf_rsi = (register_t)&sfp->sf_si;	/* arg 2 in %rsi */
640 	regs->tf_rdx = (register_t)&sfp->sf_sc;	/* arg 3 in %rdx */
641 
642 	sf.sf_handler = catcher;
643 	/* Fill in POSIX parts. */
644 	ksiginfo_to_lsiginfo(ksi, &sf.sf_si, sig);
645 
646 	/* Copy the sigframe out to the user's stack. */
647 	if (copyout(&sf, sfp, sizeof(*sfp)) != 0) {
648 #ifdef DEBUG
649 		printf("process %ld has trashed its stack\n", (long)p->p_pid);
650 #endif
651 		PROC_LOCK(p);
652 		sigexit(td, SIGILL);
653 	}
654 
655 	regs->tf_rsp = (long)sfp;
656 	regs->tf_rip = linux_rt_sigcode;
657 	regs->tf_rflags &= ~(PSL_T | PSL_D);
658 	regs->tf_cs = _ucodesel;
659 	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
660 	PROC_LOCK(p);
661 	mtx_lock(&psp->ps_mtx);
662 }
663 
664 #define	LINUX_VSYSCALL_START		(-10UL << 20)
665 #define	LINUX_VSYSCALL_SZ		1024
666 
667 const unsigned long linux_vsyscall_vector[] = {
668 	LINUX_SYS_gettimeofday,
669 	LINUX_SYS_linux_time,
670 				/* getcpu not implemented */
671 };
672 
673 static int
674 linux_vsyscall(struct thread *td)
675 {
676 	struct trapframe *frame;
677 	uint64_t retqaddr;
678 	int code, traced;
679 	int error;
680 
681 	frame = td->td_frame;
682 
683 	/* Check %rip for vsyscall area. */
684 	if (__predict_true(frame->tf_rip < LINUX_VSYSCALL_START))
685 		return (EINVAL);
686 	if ((frame->tf_rip & (LINUX_VSYSCALL_SZ - 1)) != 0)
687 		return (EINVAL);
688 	code = (frame->tf_rip - LINUX_VSYSCALL_START) / LINUX_VSYSCALL_SZ;
689 	if (code >= nitems(linux_vsyscall_vector))
690 		return (EINVAL);
691 
692 	/*
693 	 * vsyscall called as callq *(%rax), so we must
694 	 * use return address from %rsp and also fixup %rsp.
695 	 */
696 	error = copyin((void *)frame->tf_rsp, &retqaddr, sizeof(retqaddr));
697 	if (error)
698 		return (error);
699 
700 	frame->tf_rip = retqaddr;
701 	frame->tf_rax = linux_vsyscall_vector[code];
702 	frame->tf_rsp += 8;
703 
704 	traced = (frame->tf_flags & PSL_T);
705 
706 	amd64_syscall(td, traced);
707 
708 	return (0);
709 }
710 
711 struct sysentvec elf_linux_sysvec = {
712 	.sv_size	= LINUX_SYS_MAXSYSCALL,
713 	.sv_table	= linux_sysent,
714 	.sv_errsize	= ELAST + 1,
715 	.sv_errtbl	= linux_errtbl,
716 	.sv_transtrap	= linux_translate_traps,
717 	.sv_fixup	= linux_fixup_elf,
718 	.sv_sendsig	= linux_rt_sendsig,
719 	.sv_sigcode	= &_binary_linux_locore_o_start,
720 	.sv_szsigcode	= &linux_szsigcode,
721 	.sv_name	= "Linux ELF64",
722 	.sv_coredump	= elf64_coredump,
723 	.sv_imgact_try	= linux_exec_imgact_try,
724 	.sv_minsigstksz	= LINUX_MINSIGSTKSZ,
725 	.sv_minuser	= VM_MIN_ADDRESS,
726 	.sv_maxuser	= VM_MAXUSER_ADDRESS,
727 	.sv_usrstack	= USRSTACK,
728 	.sv_psstrings	= PS_STRINGS,
729 	.sv_stackprot	= VM_PROT_ALL,
730 	.sv_copyout_strings = linux_copyout_strings,
731 	.sv_setregs	= linux_exec_setregs,
732 	.sv_fixlimit	= NULL,
733 	.sv_maxssiz	= NULL,
734 	.sv_flags	= SV_ABI_LINUX | SV_LP64 | SV_SHP,
735 	.sv_set_syscall_retval = linux_set_syscall_retval,
736 	.sv_fetch_syscall_args = linux_fetch_syscall_args,
737 	.sv_syscallnames = NULL,
738 	.sv_shared_page_base = SHAREDPAGE,
739 	.sv_shared_page_len = PAGE_SIZE,
740 	.sv_schedtail	= linux_schedtail,
741 	.sv_thread_detach = linux_thread_detach,
742 	.sv_trap	= linux_vsyscall,
743 };
744 
745 static void
746 linux_vdso_install(void *param)
747 {
748 
749 	amd64_lower_shared_page(&elf_linux_sysvec);
750 
751 	linux_szsigcode = (&_binary_linux_locore_o_end -
752 	    &_binary_linux_locore_o_start);
753 
754 	if (linux_szsigcode > elf_linux_sysvec.sv_shared_page_len)
755 		panic("Linux invalid vdso size\n");
756 
757 	__elfN(linux_vdso_fixup)(&elf_linux_sysvec);
758 
759 	linux_shared_page_obj = __elfN(linux_shared_page_init)
760 	    (&linux_shared_page_mapping);
761 
762 	__elfN(linux_vdso_reloc)(&elf_linux_sysvec);
763 
764 	bcopy(elf_linux_sysvec.sv_sigcode, linux_shared_page_mapping,
765 	    linux_szsigcode);
766 	elf_linux_sysvec.sv_shared_page_obj = linux_shared_page_obj;
767 
768 	linux_kplatform = linux_shared_page_mapping +
769 	    (linux_platform - (caddr_t)elf_linux_sysvec.sv_shared_page_base);
770 }
771 SYSINIT(elf_linux_vdso_init, SI_SUB_EXEC, SI_ORDER_ANY,
772     linux_vdso_install, NULL);
773 
774 static void
775 linux_vdso_deinstall(void *param)
776 {
777 
778 	__elfN(linux_shared_page_fini)(linux_shared_page_obj);
779 }
780 SYSUNINIT(elf_linux_vdso_uninit, SI_SUB_EXEC, SI_ORDER_FIRST,
781     linux_vdso_deinstall, NULL);
782 
783 static char GNULINUX_ABI_VENDOR[] = "GNU";
784 static int GNULINUX_ABI_DESC = 0;
785 
786 static bool
787 linux_trans_osrel(const Elf_Note *note, int32_t *osrel)
788 {
789 	const Elf32_Word *desc;
790 	uintptr_t p;
791 
792 	p = (uintptr_t)(note + 1);
793 	p += roundup2(note->n_namesz, sizeof(Elf32_Addr));
794 
795 	desc = (const Elf32_Word *)p;
796 	if (desc[0] != GNULINUX_ABI_DESC)
797 		return (false);
798 
799 	/*
800 	 * For Linux we encode osrel using the Linux convention of
801 	 * 	(version << 16) | (major << 8) | (minor)
802 	 * See macro in linux_mib.h
803 	 */
804 	*osrel = LINUX_KERNVER(desc[1], desc[2], desc[3]);
805 
806 	return (true);
807 }
808 
809 static Elf_Brandnote linux64_brandnote = {
810 	.hdr.n_namesz	= sizeof(GNULINUX_ABI_VENDOR),
811 	.hdr.n_descsz	= 16,
812 	.hdr.n_type	= 1,
813 	.vendor		= GNULINUX_ABI_VENDOR,
814 	.flags		= BN_TRANSLATE_OSREL,
815 	.trans_osrel	= linux_trans_osrel
816 };
817 
818 static Elf64_Brandinfo linux_glibc2brand = {
819 	.brand		= ELFOSABI_LINUX,
820 	.machine	= EM_X86_64,
821 	.compat_3_brand	= "Linux",
822 	.emul_path	= "/compat/linux",
823 	.interp_path	= "/lib64/ld-linux-x86-64.so.2",
824 	.sysvec		= &elf_linux_sysvec,
825 	.interp_newpath	= NULL,
826 	.brand_note	= &linux64_brandnote,
827 	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
828 };
829 
830 static Elf64_Brandinfo linux_glibc2brandshort = {
831 	.brand		= ELFOSABI_LINUX,
832 	.machine	= EM_X86_64,
833 	.compat_3_brand	= "Linux",
834 	.emul_path	= "/compat/linux",
835 	.interp_path	= "/lib64/ld-linux.so.2",
836 	.sysvec		= &elf_linux_sysvec,
837 	.interp_newpath	= NULL,
838 	.brand_note	= &linux64_brandnote,
839 	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
840 };
841 
842 static Elf64_Brandinfo linux_muslbrand = {
843 	.brand		= ELFOSABI_LINUX,
844 	.machine	= EM_X86_64,
845 	.compat_3_brand	= "Linux",
846 	.emul_path	= "/compat/linux",
847 	.interp_path	= "/lib/ld-musl-x86_64.so.1",
848 	.sysvec		= &elf_linux_sysvec,
849 	.interp_newpath	= NULL,
850 	.brand_note	= &linux64_brandnote,
851 	.flags		= BI_CAN_EXEC_DYN | BI_BRAND_NOTE
852 };
853 
854 Elf64_Brandinfo *linux_brandlist[] = {
855 	&linux_glibc2brand,
856 	&linux_glibc2brandshort,
857 	&linux_muslbrand,
858 	NULL
859 };
860 
861 static int
862 linux64_elf_modevent(module_t mod, int type, void *data)
863 {
864 	Elf64_Brandinfo **brandinfo;
865 	int error;
866 	struct linux_ioctl_handler **lihp;
867 
868 	error = 0;
869 
870 	switch(type) {
871 	case MOD_LOAD:
872 		for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
873 		     ++brandinfo)
874 			if (elf64_insert_brand_entry(*brandinfo) < 0)
875 				error = EINVAL;
876 		if (error == 0) {
877 			SET_FOREACH(lihp, linux_ioctl_handler_set)
878 				linux_ioctl_register_handler(*lihp);
879 			LIST_INIT(&futex_list);
880 			mtx_init(&futex_mtx, "ftllk64", NULL, MTX_DEF);
881 			stclohz = (stathz ? stathz : hz);
882 			if (bootverbose)
883 				printf("Linux x86-64 ELF exec handler installed\n");
884 		} else
885 			printf("cannot insert Linux x86-64 ELF brand handler\n");
886 		break;
887 	case MOD_UNLOAD:
888 		for (brandinfo = &linux_brandlist[0]; *brandinfo != NULL;
889 		     ++brandinfo)
890 			if (elf64_brand_inuse(*brandinfo))
891 				error = EBUSY;
892 		if (error == 0) {
893 			for (brandinfo = &linux_brandlist[0];
894 			     *brandinfo != NULL; ++brandinfo)
895 				if (elf64_remove_brand_entry(*brandinfo) < 0)
896 					error = EINVAL;
897 		}
898 		if (error == 0) {
899 			SET_FOREACH(lihp, linux_ioctl_handler_set)
900 				linux_ioctl_unregister_handler(*lihp);
901 			mtx_destroy(&futex_mtx);
902 			if (bootverbose)
903 				printf("Linux ELF exec handler removed\n");
904 		} else
905 			printf("Could not deinstall ELF interpreter entry\n");
906 		break;
907 	default:
908 		return (EOPNOTSUPP);
909 	}
910 	return (error);
911 }
912 
913 static moduledata_t linux64_elf_mod = {
914 	"linux64elf",
915 	linux64_elf_modevent,
916 	0
917 };
918 
919 DECLARE_MODULE_TIED(linux64elf, linux64_elf_mod, SI_SUB_EXEC, SI_ORDER_ANY);
920 MODULE_DEPEND(linux64elf, linux_common, 1, 1, 1);
921 FEATURE(linux64, "Linux 64bit support");
922