1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
4 * Copyright (C) 2002- 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
5 */
6
7 #include <stdlib.h>
8 #include <stdbool.h>
9 #include <unistd.h>
10 #include <sched.h>
11 #include <errno.h>
12 #include <string.h>
13 #include <sys/mman.h>
14 #include <sys/wait.h>
15 #include <asm/unistd.h>
16 #include <as-layout.h>
17 #include <init.h>
18 #include <kern_util.h>
19 #include <mem.h>
20 #include <os.h>
21 #include <ptrace_user.h>
22 #include <registers.h>
23 #include <skas.h>
24 #include <sysdep/stub.h>
25 #include <linux/threads.h>
26
is_skas_winch(int pid,int fd,void * data)27 int is_skas_winch(int pid, int fd, void *data)
28 {
29 return pid == getpgrp();
30 }
31
ptrace_dump_regs(int pid)32 static int ptrace_dump_regs(int pid)
33 {
34 unsigned long regs[MAX_REG_NR];
35 int i;
36
37 if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
38 return -errno;
39
40 printk(UM_KERN_ERR "Stub registers -\n");
41 for (i = 0; i < ARRAY_SIZE(regs); i++)
42 printk(UM_KERN_ERR "\t%d - %lx\n", i, regs[i]);
43
44 return 0;
45 }
46
47 /*
48 * Signals that are OK to receive in the stub - we'll just continue it.
49 * SIGWINCH will happen when UML is inside a detached screen.
50 */
51 #define STUB_SIG_MASK ((1 << SIGALRM) | (1 << SIGWINCH))
52
53 /* Signals that the stub will finish with - anything else is an error */
54 #define STUB_DONE_MASK (1 << SIGTRAP)
55
wait_stub_done(int pid)56 void wait_stub_done(int pid)
57 {
58 int n, status, err;
59
60 while (1) {
61 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
62 if ((n < 0) || !WIFSTOPPED(status))
63 goto bad_wait;
64
65 if (((1 << WSTOPSIG(status)) & STUB_SIG_MASK) == 0)
66 break;
67
68 err = ptrace(PTRACE_CONT, pid, 0, 0);
69 if (err) {
70 printk(UM_KERN_ERR "wait_stub_done : continue failed, "
71 "errno = %d\n", errno);
72 fatal_sigsegv();
73 }
74 }
75
76 if (((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0)
77 return;
78
79 bad_wait:
80 err = ptrace_dump_regs(pid);
81 if (err)
82 printk(UM_KERN_ERR "Failed to get registers from stub, "
83 "errno = %d\n", -err);
84 printk(UM_KERN_ERR "wait_stub_done : failed to wait for SIGTRAP, "
85 "pid = %d, n = %d, errno = %d, status = 0x%x\n", pid, n, errno,
86 status);
87 fatal_sigsegv();
88 }
89
90 extern unsigned long current_stub_stack(void);
91
get_skas_faultinfo(int pid,struct faultinfo * fi,unsigned long * aux_fp_regs)92 static void get_skas_faultinfo(int pid, struct faultinfo *fi, unsigned long *aux_fp_regs)
93 {
94 int err;
95
96 err = get_fp_registers(pid, aux_fp_regs);
97 if (err < 0) {
98 printk(UM_KERN_ERR "save_fp_registers returned %d\n",
99 err);
100 fatal_sigsegv();
101 }
102 err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV);
103 if (err) {
104 printk(UM_KERN_ERR "Failed to continue stub, pid = %d, "
105 "errno = %d\n", pid, errno);
106 fatal_sigsegv();
107 }
108 wait_stub_done(pid);
109
110 /*
111 * faultinfo is prepared by the stub_segv_handler at start of
112 * the stub stack page. We just have to copy it.
113 */
114 memcpy(fi, (void *)current_stub_stack(), sizeof(*fi));
115
116 err = put_fp_registers(pid, aux_fp_regs);
117 if (err < 0) {
118 printk(UM_KERN_ERR "put_fp_registers returned %d\n",
119 err);
120 fatal_sigsegv();
121 }
122 }
123
handle_segv(int pid,struct uml_pt_regs * regs,unsigned long * aux_fp_regs)124 static void handle_segv(int pid, struct uml_pt_regs *regs, unsigned long *aux_fp_regs)
125 {
126 get_skas_faultinfo(pid, ®s->faultinfo, aux_fp_regs);
127 segv(regs->faultinfo, 0, 1, NULL);
128 }
129
130 /*
131 * To use the same value of using_sysemu as the caller, ask it that value
132 * (in local_using_sysemu
133 */
handle_trap(int pid,struct uml_pt_regs * regs,int local_using_sysemu)134 static void handle_trap(int pid, struct uml_pt_regs *regs,
135 int local_using_sysemu)
136 {
137 int err, status;
138
139 if ((UPT_IP(regs) >= STUB_START) && (UPT_IP(regs) < STUB_END))
140 fatal_sigsegv();
141
142 if (!local_using_sysemu)
143 {
144 err = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET,
145 __NR_getpid);
146 if (err < 0) {
147 printk(UM_KERN_ERR "handle_trap - nullifying syscall "
148 "failed, errno = %d\n", errno);
149 fatal_sigsegv();
150 }
151
152 err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
153 if (err < 0) {
154 printk(UM_KERN_ERR "handle_trap - continuing to end of "
155 "syscall failed, errno = %d\n", errno);
156 fatal_sigsegv();
157 }
158
159 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
160 if ((err < 0) || !WIFSTOPPED(status) ||
161 (WSTOPSIG(status) != SIGTRAP + 0x80)) {
162 err = ptrace_dump_regs(pid);
163 if (err)
164 printk(UM_KERN_ERR "Failed to get registers "
165 "from process, errno = %d\n", -err);
166 printk(UM_KERN_ERR "handle_trap - failed to wait at "
167 "end of syscall, errno = %d, status = %d\n",
168 errno, status);
169 fatal_sigsegv();
170 }
171 }
172
173 handle_syscall(regs);
174 }
175
176 extern char __syscall_stub_start[];
177
178 /**
179 * userspace_tramp() - userspace trampoline
180 * @stack: pointer to the new userspace stack page, can be NULL, if? FIXME:
181 *
182 * The userspace trampoline is used to setup a new userspace process in start_userspace() after it was clone()'ed.
183 * This function will run on a temporary stack page.
184 * It ptrace()'es itself, then
185 * Two pages are mapped into the userspace address space:
186 * - STUB_CODE (with EXEC), which contains the skas stub code
187 * - STUB_DATA (with R/W), which contains a data page that is used to transfer certain data between the UML userspace process and the UML kernel.
188 * Also for the userspace process a SIGSEGV handler is installed to catch pagefaults in the userspace process.
189 * And last the process stops itself to give control to the UML kernel for this userspace process.
190 *
191 * Return: Always zero, otherwise the current userspace process is ended with non null exit() call
192 */
userspace_tramp(void * stack)193 static int userspace_tramp(void *stack)
194 {
195 void *addr;
196 int fd;
197 unsigned long long offset;
198
199 ptrace(PTRACE_TRACEME, 0, 0, 0);
200
201 signal(SIGTERM, SIG_DFL);
202 signal(SIGWINCH, SIG_IGN);
203
204 /*
205 * This has a pte, but it can't be mapped in with the usual
206 * tlb_flush mechanism because this is part of that mechanism
207 */
208 fd = phys_mapping(to_phys(__syscall_stub_start), &offset);
209 addr = mmap64((void *) STUB_CODE, UM_KERN_PAGE_SIZE,
210 PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
211 if (addr == MAP_FAILED) {
212 printk(UM_KERN_ERR "mapping mmap stub at 0x%lx failed, "
213 "errno = %d\n", STUB_CODE, errno);
214 exit(1);
215 }
216
217 if (stack != NULL) {
218 fd = phys_mapping(to_phys(stack), &offset);
219 addr = mmap((void *) STUB_DATA,
220 UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
221 MAP_FIXED | MAP_SHARED, fd, offset);
222 if (addr == MAP_FAILED) {
223 printk(UM_KERN_ERR "mapping segfault stack "
224 "at 0x%lx failed, errno = %d\n",
225 STUB_DATA, errno);
226 exit(1);
227 }
228 }
229 if (stack != NULL) {
230 struct sigaction sa;
231
232 unsigned long v = STUB_CODE +
233 (unsigned long) stub_segv_handler -
234 (unsigned long) __syscall_stub_start;
235
236 set_sigstack((void *) STUB_DATA, UM_KERN_PAGE_SIZE);
237 sigemptyset(&sa.sa_mask);
238 sa.sa_flags = SA_ONSTACK | SA_NODEFER | SA_SIGINFO;
239 sa.sa_sigaction = (void *) v;
240 sa.sa_restorer = NULL;
241 if (sigaction(SIGSEGV, &sa, NULL) < 0) {
242 printk(UM_KERN_ERR "userspace_tramp - setting SIGSEGV "
243 "handler failed - errno = %d\n", errno);
244 exit(1);
245 }
246 }
247
248 kill(os_getpid(), SIGSTOP);
249 return 0;
250 }
251
252 int userspace_pid[NR_CPUS];
253 int kill_userspace_mm[NR_CPUS];
254
255 /**
256 * start_userspace() - prepare a new userspace process
257 * @stub_stack: pointer to the stub stack. Can be NULL, if? FIXME:
258 *
259 * Setups a new temporary stack page that is used while userspace_tramp() runs
260 * Clones the kernel process into a new userspace process, with FDs only.
261 *
262 * Return: When positive: the process id of the new userspace process,
263 * when negative: an error number.
264 * FIXME: can PIDs become negative?!
265 */
start_userspace(unsigned long stub_stack)266 int start_userspace(unsigned long stub_stack)
267 {
268 void *stack;
269 unsigned long sp;
270 int pid, status, n, flags, err;
271
272 /* setup a temporary stack page */
273 stack = mmap(NULL, UM_KERN_PAGE_SIZE,
274 PROT_READ | PROT_WRITE | PROT_EXEC,
275 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
276 if (stack == MAP_FAILED) {
277 err = -errno;
278 printk(UM_KERN_ERR "start_userspace : mmap failed, "
279 "errno = %d\n", errno);
280 return err;
281 }
282
283 /* set stack pointer to the end of the stack page, so it can grow downwards */
284 sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *);
285
286 flags = CLONE_FILES | SIGCHLD;
287
288 /* clone into new userspace process */
289 pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
290 if (pid < 0) {
291 err = -errno;
292 printk(UM_KERN_ERR "start_userspace : clone failed, "
293 "errno = %d\n", errno);
294 return err;
295 }
296
297 do {
298 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
299 if (n < 0) {
300 err = -errno;
301 printk(UM_KERN_ERR "start_userspace : wait failed, "
302 "errno = %d\n", errno);
303 goto out_kill;
304 }
305 } while (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGALRM));
306
307 if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) {
308 err = -EINVAL;
309 printk(UM_KERN_ERR "start_userspace : expected SIGSTOP, got "
310 "status = %d\n", status);
311 goto out_kill;
312 }
313
314 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
315 (void *) PTRACE_O_TRACESYSGOOD) < 0) {
316 err = -errno;
317 printk(UM_KERN_ERR "start_userspace : PTRACE_OLDSETOPTIONS "
318 "failed, errno = %d\n", errno);
319 goto out_kill;
320 }
321
322 if (munmap(stack, UM_KERN_PAGE_SIZE) < 0) {
323 err = -errno;
324 printk(UM_KERN_ERR "start_userspace : munmap failed, "
325 "errno = %d\n", errno);
326 goto out_kill;
327 }
328
329 return pid;
330
331 out_kill:
332 os_kill_ptraced_process(pid, 1);
333 return err;
334 }
335
userspace(struct uml_pt_regs * regs,unsigned long * aux_fp_regs)336 void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs)
337 {
338 int err, status, op, pid = userspace_pid[0];
339 /* To prevent races if using_sysemu changes under us.*/
340 int local_using_sysemu;
341 siginfo_t si;
342
343 /* Handle any immediate reschedules or signals */
344 interrupt_end();
345
346 while (1) {
347 if (kill_userspace_mm[0])
348 fatal_sigsegv();
349
350 /*
351 * This can legitimately fail if the process loads a
352 * bogus value into a segment register. It will
353 * segfault and PTRACE_GETREGS will read that value
354 * out of the process. However, PTRACE_SETREGS will
355 * fail. In this case, there is nothing to do but
356 * just kill the process.
357 */
358 if (ptrace(PTRACE_SETREGS, pid, 0, regs->gp)) {
359 printk(UM_KERN_ERR "userspace - ptrace set regs "
360 "failed, errno = %d\n", errno);
361 fatal_sigsegv();
362 }
363
364 if (put_fp_registers(pid, regs->fp)) {
365 printk(UM_KERN_ERR "userspace - ptrace set fp regs "
366 "failed, errno = %d\n", errno);
367 fatal_sigsegv();
368 }
369
370 /* Now we set local_using_sysemu to be used for one loop */
371 local_using_sysemu = get_using_sysemu();
372
373 op = SELECT_PTRACE_OPERATION(local_using_sysemu,
374 singlestepping(NULL));
375
376 if (ptrace(op, pid, 0, 0)) {
377 printk(UM_KERN_ERR "userspace - ptrace continue "
378 "failed, op = %d, errno = %d\n", op, errno);
379 fatal_sigsegv();
380 }
381
382 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
383 if (err < 0) {
384 printk(UM_KERN_ERR "userspace - wait failed, "
385 "errno = %d\n", errno);
386 fatal_sigsegv();
387 }
388
389 regs->is_user = 1;
390 if (ptrace(PTRACE_GETREGS, pid, 0, regs->gp)) {
391 printk(UM_KERN_ERR "userspace - PTRACE_GETREGS failed, "
392 "errno = %d\n", errno);
393 fatal_sigsegv();
394 }
395
396 if (get_fp_registers(pid, regs->fp)) {
397 printk(UM_KERN_ERR "userspace - get_fp_registers failed, "
398 "errno = %d\n", errno);
399 fatal_sigsegv();
400 }
401
402 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
403
404 if (WIFSTOPPED(status)) {
405 int sig = WSTOPSIG(status);
406
407 ptrace(PTRACE_GETSIGINFO, pid, 0, (struct siginfo *)&si);
408
409 switch (sig) {
410 case SIGSEGV:
411 if (PTRACE_FULL_FAULTINFO) {
412 get_skas_faultinfo(pid,
413 ®s->faultinfo, aux_fp_regs);
414 (*sig_info[SIGSEGV])(SIGSEGV, (struct siginfo *)&si,
415 regs);
416 }
417 else handle_segv(pid, regs, aux_fp_regs);
418 break;
419 case SIGTRAP + 0x80:
420 handle_trap(pid, regs, local_using_sysemu);
421 break;
422 case SIGTRAP:
423 relay_signal(SIGTRAP, (struct siginfo *)&si, regs);
424 break;
425 case SIGALRM:
426 break;
427 case SIGIO:
428 case SIGILL:
429 case SIGBUS:
430 case SIGFPE:
431 case SIGWINCH:
432 block_signals_trace();
433 (*sig_info[sig])(sig, (struct siginfo *)&si, regs);
434 unblock_signals_trace();
435 break;
436 default:
437 printk(UM_KERN_ERR "userspace - child stopped "
438 "with signal %d\n", sig);
439 fatal_sigsegv();
440 }
441 pid = userspace_pid[0];
442 interrupt_end();
443
444 /* Avoid -ERESTARTSYS handling in host */
445 if (PT_SYSCALL_NR_OFFSET != PT_SYSCALL_RET_OFFSET)
446 PT_SYSCALL_NR(regs->gp) = -1;
447 }
448 }
449 }
450
451 static unsigned long thread_regs[MAX_REG_NR];
452 static unsigned long thread_fp_regs[FP_SIZE];
453
init_thread_regs(void)454 static int __init init_thread_regs(void)
455 {
456 get_safe_registers(thread_regs, thread_fp_regs);
457 /* Set parent's instruction pointer to start of clone-stub */
458 thread_regs[REGS_IP_INDEX] = STUB_CODE +
459 (unsigned long) stub_clone_handler -
460 (unsigned long) __syscall_stub_start;
461 thread_regs[REGS_SP_INDEX] = STUB_DATA + UM_KERN_PAGE_SIZE -
462 sizeof(void *);
463 #ifdef __SIGNAL_FRAMESIZE
464 thread_regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
465 #endif
466 return 0;
467 }
468
469 __initcall(init_thread_regs);
470
copy_context_skas0(unsigned long new_stack,int pid)471 int copy_context_skas0(unsigned long new_stack, int pid)
472 {
473 int err;
474 unsigned long current_stack = current_stub_stack();
475 struct stub_data *data = (struct stub_data *) current_stack;
476 struct stub_data *child_data = (struct stub_data *) new_stack;
477 unsigned long long new_offset;
478 int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset);
479
480 /*
481 * prepare offset and fd of child's stack as argument for parent's
482 * and child's mmap2 calls
483 */
484 *data = ((struct stub_data) {
485 .offset = MMAP_OFFSET(new_offset),
486 .fd = new_fd
487 });
488
489 err = ptrace_setregs(pid, thread_regs);
490 if (err < 0) {
491 err = -errno;
492 printk(UM_KERN_ERR "copy_context_skas0 : PTRACE_SETREGS "
493 "failed, pid = %d, errno = %d\n", pid, -err);
494 return err;
495 }
496
497 err = put_fp_registers(pid, thread_fp_regs);
498 if (err < 0) {
499 printk(UM_KERN_ERR "copy_context_skas0 : put_fp_registers "
500 "failed, pid = %d, err = %d\n", pid, err);
501 return err;
502 }
503
504 /* set a well known return code for detection of child write failure */
505 child_data->err = 12345678;
506
507 /*
508 * Wait, until parent has finished its work: read child's pid from
509 * parent's stack, and check, if bad result.
510 */
511 err = ptrace(PTRACE_CONT, pid, 0, 0);
512 if (err) {
513 err = -errno;
514 printk(UM_KERN_ERR "Failed to continue new process, pid = %d, "
515 "errno = %d\n", pid, errno);
516 return err;
517 }
518
519 wait_stub_done(pid);
520
521 pid = data->err;
522 if (pid < 0) {
523 printk(UM_KERN_ERR "copy_context_skas0 - stub-parent reports "
524 "error %d\n", -pid);
525 return pid;
526 }
527
528 /*
529 * Wait, until child has finished too: read child's result from
530 * child's stack and check it.
531 */
532 wait_stub_done(pid);
533 if (child_data->err != STUB_DATA) {
534 printk(UM_KERN_ERR "copy_context_skas0 - stub-child reports "
535 "error %ld\n", child_data->err);
536 err = child_data->err;
537 goto out_kill;
538 }
539
540 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
541 (void *)PTRACE_O_TRACESYSGOOD) < 0) {
542 err = -errno;
543 printk(UM_KERN_ERR "copy_context_skas0 : PTRACE_OLDSETOPTIONS "
544 "failed, errno = %d\n", errno);
545 goto out_kill;
546 }
547
548 return pid;
549
550 out_kill:
551 os_kill_ptraced_process(pid, 1);
552 return err;
553 }
554
new_thread(void * stack,jmp_buf * buf,void (* handler)(void))555 void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
556 {
557 (*buf)[0].JB_IP = (unsigned long) handler;
558 (*buf)[0].JB_SP = (unsigned long) stack + UM_THREAD_SIZE -
559 sizeof(void *);
560 }
561
562 #define INIT_JMP_NEW_THREAD 0
563 #define INIT_JMP_CALLBACK 1
564 #define INIT_JMP_HALT 2
565 #define INIT_JMP_REBOOT 3
566
switch_threads(jmp_buf * me,jmp_buf * you)567 void switch_threads(jmp_buf *me, jmp_buf *you)
568 {
569 if (UML_SETJMP(me) == 0)
570 UML_LONGJMP(you, 1);
571 }
572
573 static jmp_buf initial_jmpbuf;
574
575 /* XXX Make these percpu */
576 static void (*cb_proc)(void *arg);
577 static void *cb_arg;
578 static jmp_buf *cb_back;
579
start_idle_thread(void * stack,jmp_buf * switch_buf)580 int start_idle_thread(void *stack, jmp_buf *switch_buf)
581 {
582 int n;
583
584 set_handler(SIGWINCH);
585
586 /*
587 * Can't use UML_SETJMP or UML_LONGJMP here because they save
588 * and restore signals, with the possible side-effect of
589 * trying to handle any signals which came when they were
590 * blocked, which can't be done on this stack.
591 * Signals must be blocked when jumping back here and restored
592 * after returning to the jumper.
593 */
594 n = setjmp(initial_jmpbuf);
595 switch (n) {
596 case INIT_JMP_NEW_THREAD:
597 (*switch_buf)[0].JB_IP = (unsigned long) uml_finishsetup;
598 (*switch_buf)[0].JB_SP = (unsigned long) stack +
599 UM_THREAD_SIZE - sizeof(void *);
600 break;
601 case INIT_JMP_CALLBACK:
602 (*cb_proc)(cb_arg);
603 longjmp(*cb_back, 1);
604 break;
605 case INIT_JMP_HALT:
606 kmalloc_ok = 0;
607 return 0;
608 case INIT_JMP_REBOOT:
609 kmalloc_ok = 0;
610 return 1;
611 default:
612 printk(UM_KERN_ERR "Bad sigsetjmp return in "
613 "start_idle_thread - %d\n", n);
614 fatal_sigsegv();
615 }
616 longjmp(*switch_buf, 1);
617
618 /* unreachable */
619 printk(UM_KERN_ERR "impossible long jump!");
620 fatal_sigsegv();
621 return 0;
622 }
623
initial_thread_cb_skas(void (* proc)(void *),void * arg)624 void initial_thread_cb_skas(void (*proc)(void *), void *arg)
625 {
626 jmp_buf here;
627
628 cb_proc = proc;
629 cb_arg = arg;
630 cb_back = &here;
631
632 block_signals_trace();
633 if (UML_SETJMP(&here) == 0)
634 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK);
635 unblock_signals_trace();
636
637 cb_proc = NULL;
638 cb_arg = NULL;
639 cb_back = NULL;
640 }
641
halt_skas(void)642 void halt_skas(void)
643 {
644 block_signals_trace();
645 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT);
646 }
647
648 static bool noreboot;
649
noreboot_cmd_param(char * str,int * add)650 static int __init noreboot_cmd_param(char *str, int *add)
651 {
652 noreboot = true;
653 return 0;
654 }
655
656 __uml_setup("noreboot", noreboot_cmd_param,
657 "noreboot\n"
658 " Rather than rebooting, exit always, akin to QEMU's -no-reboot option.\n"
659 " This is useful if you're using CONFIG_PANIC_TIMEOUT in order to catch\n"
660 " crashes in CI\n");
661
reboot_skas(void)662 void reboot_skas(void)
663 {
664 block_signals_trace();
665 UML_LONGJMP(&initial_jmpbuf, noreboot ? INIT_JMP_HALT : INIT_JMP_REBOOT);
666 }
667
__switch_mm(struct mm_id * mm_idp)668 void __switch_mm(struct mm_id *mm_idp)
669 {
670 userspace_pid[0] = mm_idp->u.pid;
671 kill_userspace_mm[0] = mm_idp->kill;
672 }
673