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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
27int is_skas_winch(int pid, int fd, void *data)
28{
29 return pid == getpgrp();
30}
31
32static const char *ptrace_reg_name(int idx)
33{
34#define R(n) case HOST_##n: return #n
35
36 switch (idx) {
37#ifdef __x86_64__
38 R(BX);
39 R(CX);
40 R(DI);
41 R(SI);
42 R(DX);
43 R(BP);
44 R(AX);
45 R(R8);
46 R(R9);
47 R(R10);
48 R(R11);
49 R(R12);
50 R(R13);
51 R(R14);
52 R(R15);
53 R(ORIG_AX);
54 R(CS);
55 R(SS);
56 R(EFLAGS);
57#elif defined(__i386__)
58 R(IP);
59 R(SP);
60 R(EFLAGS);
61 R(AX);
62 R(BX);
63 R(CX);
64 R(DX);
65 R(SI);
66 R(DI);
67 R(BP);
68 R(CS);
69 R(SS);
70 R(DS);
71 R(FS);
72 R(ES);
73 R(GS);
74 R(ORIG_AX);
75#endif
76 }
77 return "";
78}
79
80static int ptrace_dump_regs(int pid)
81{
82 unsigned long regs[MAX_REG_NR];
83 int i;
84
85 if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
86 return -errno;
87
88 printk(UM_KERN_ERR "Stub registers -\n");
89 for (i = 0; i < ARRAY_SIZE(regs); i++) {
90 const char *regname = ptrace_reg_name(i);
91
92 printk(UM_KERN_ERR "\t%s\t(%2d): %lx\n", regname, i, regs[i]);
93 }
94
95 return 0;
96}
97
98/*
99 * Signals that are OK to receive in the stub - we'll just continue it.
100 * SIGWINCH will happen when UML is inside a detached screen.
101 */
102#define STUB_SIG_MASK ((1 << SIGALRM) | (1 << SIGWINCH))
103
104/* Signals that the stub will finish with - anything else is an error */
105#define STUB_DONE_MASK (1 << SIGTRAP)
106
107void wait_stub_done(int pid)
108{
109 int n, status, err;
110
111 while (1) {
112 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
113 if ((n < 0) || !WIFSTOPPED(status))
114 goto bad_wait;
115
116 if (((1 << WSTOPSIG(status)) & STUB_SIG_MASK) == 0)
117 break;
118
119 err = ptrace(PTRACE_CONT, pid, 0, 0);
120 if (err) {
121 printk(UM_KERN_ERR "wait_stub_done : continue failed, "
122 "errno = %d\n", errno);
123 fatal_sigsegv();
124 }
125 }
126
127 if (((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0)
128 return;
129
130bad_wait:
131 err = ptrace_dump_regs(pid);
132 if (err)
133 printk(UM_KERN_ERR "Failed to get registers from stub, "
134 "errno = %d\n", -err);
135 printk(UM_KERN_ERR "wait_stub_done : failed to wait for SIGTRAP, "
136 "pid = %d, n = %d, errno = %d, status = 0x%x\n", pid, n, errno,
137 status);
138 fatal_sigsegv();
139}
140
141extern unsigned long current_stub_stack(void);
142
143static void get_skas_faultinfo(int pid, struct faultinfo *fi, unsigned long *aux_fp_regs)
144{
145 int err;
146
147 err = get_fp_registers(pid, aux_fp_regs);
148 if (err < 0) {
149 printk(UM_KERN_ERR "save_fp_registers returned %d\n",
150 err);
151 fatal_sigsegv();
152 }
153 err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV);
154 if (err) {
155 printk(UM_KERN_ERR "Failed to continue stub, pid = %d, "
156 "errno = %d\n", pid, errno);
157 fatal_sigsegv();
158 }
159 wait_stub_done(pid);
160
161 /*
162 * faultinfo is prepared by the stub_segv_handler at start of
163 * the stub stack page. We just have to copy it.
164 */
165 memcpy(fi, (void *)current_stub_stack(), sizeof(*fi));
166
167 err = put_fp_registers(pid, aux_fp_regs);
168 if (err < 0) {
169 printk(UM_KERN_ERR "put_fp_registers returned %d\n",
170 err);
171 fatal_sigsegv();
172 }
173}
174
175static void handle_segv(int pid, struct uml_pt_regs *regs, unsigned long *aux_fp_regs)
176{
177 get_skas_faultinfo(pid, ®s->faultinfo, aux_fp_regs);
178 segv(regs->faultinfo, 0, 1, NULL);
179}
180
181/*
182 * To use the same value of using_sysemu as the caller, ask it that value
183 * (in local_using_sysemu
184 */
185static void handle_trap(int pid, struct uml_pt_regs *regs,
186 int local_using_sysemu)
187{
188 int err, status;
189
190 if ((UPT_IP(regs) >= STUB_START) && (UPT_IP(regs) < STUB_END))
191 fatal_sigsegv();
192
193 if (!local_using_sysemu)
194 {
195 err = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET,
196 __NR_getpid);
197 if (err < 0) {
198 printk(UM_KERN_ERR "handle_trap - nullifying syscall "
199 "failed, errno = %d\n", errno);
200 fatal_sigsegv();
201 }
202
203 err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
204 if (err < 0) {
205 printk(UM_KERN_ERR "handle_trap - continuing to end of "
206 "syscall failed, errno = %d\n", errno);
207 fatal_sigsegv();
208 }
209
210 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
211 if ((err < 0) || !WIFSTOPPED(status) ||
212 (WSTOPSIG(status) != SIGTRAP + 0x80)) {
213 err = ptrace_dump_regs(pid);
214 if (err)
215 printk(UM_KERN_ERR "Failed to get registers "
216 "from process, errno = %d\n", -err);
217 printk(UM_KERN_ERR "handle_trap - failed to wait at "
218 "end of syscall, errno = %d, status = %d\n",
219 errno, status);
220 fatal_sigsegv();
221 }
222 }
223
224 handle_syscall(regs);
225}
226
227extern char __syscall_stub_start[];
228
229/**
230 * userspace_tramp() - userspace trampoline
231 * @stack: pointer to the new userspace stack page, can be NULL, if? FIXME:
232 *
233 * The userspace trampoline is used to setup a new userspace process in start_userspace() after it was clone()'ed.
234 * This function will run on a temporary stack page.
235 * It ptrace()'es itself, then
236 * Two pages are mapped into the userspace address space:
237 * - STUB_CODE (with EXEC), which contains the skas stub code
238 * - 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.
239 * Also for the userspace process a SIGSEGV handler is installed to catch pagefaults in the userspace process.
240 * And last the process stops itself to give control to the UML kernel for this userspace process.
241 *
242 * Return: Always zero, otherwise the current userspace process is ended with non null exit() call
243 */
244static int userspace_tramp(void *stack)
245{
246 void *addr;
247 int fd;
248 unsigned long long offset;
249
250 ptrace(PTRACE_TRACEME, 0, 0, 0);
251
252 signal(SIGTERM, SIG_DFL);
253 signal(SIGWINCH, SIG_IGN);
254
255 fd = phys_mapping(uml_to_phys(__syscall_stub_start), &offset);
256 addr = mmap64((void *) STUB_CODE, UM_KERN_PAGE_SIZE,
257 PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
258 if (addr == MAP_FAILED) {
259 printk(UM_KERN_ERR "mapping mmap stub at 0x%lx failed, "
260 "errno = %d\n", STUB_CODE, errno);
261 exit(1);
262 }
263
264 if (stack != NULL) {
265 fd = phys_mapping(uml_to_phys(stack), &offset);
266 addr = mmap((void *) STUB_DATA,
267 UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
268 MAP_FIXED | MAP_SHARED, fd, offset);
269 if (addr == MAP_FAILED) {
270 printk(UM_KERN_ERR "mapping segfault stack "
271 "at 0x%lx failed, errno = %d\n",
272 STUB_DATA, errno);
273 exit(1);
274 }
275 }
276 if (stack != NULL) {
277 struct sigaction sa;
278
279 unsigned long v = STUB_CODE +
280 (unsigned long) stub_segv_handler -
281 (unsigned long) __syscall_stub_start;
282
283 set_sigstack((void *) STUB_DATA, UM_KERN_PAGE_SIZE);
284 sigemptyset(&sa.sa_mask);
285 sa.sa_flags = SA_ONSTACK | SA_NODEFER | SA_SIGINFO;
286 sa.sa_sigaction = (void *) v;
287 sa.sa_restorer = NULL;
288 if (sigaction(SIGSEGV, &sa, NULL) < 0) {
289 printk(UM_KERN_ERR "userspace_tramp - setting SIGSEGV "
290 "handler failed - errno = %d\n", errno);
291 exit(1);
292 }
293 }
294
295 kill(os_getpid(), SIGSTOP);
296 return 0;
297}
298
299int userspace_pid[NR_CPUS];
300int kill_userspace_mm[NR_CPUS];
301
302/**
303 * start_userspace() - prepare a new userspace process
304 * @stub_stack: pointer to the stub stack. Can be NULL, if? FIXME:
305 *
306 * Setups a new temporary stack page that is used while userspace_tramp() runs
307 * Clones the kernel process into a new userspace process, with FDs only.
308 *
309 * Return: When positive: the process id of the new userspace process,
310 * when negative: an error number.
311 * FIXME: can PIDs become negative?!
312 */
313int start_userspace(unsigned long stub_stack)
314{
315 void *stack;
316 unsigned long sp;
317 int pid, status, n, flags, err;
318
319 /* setup a temporary stack page */
320 stack = mmap(NULL, UM_KERN_PAGE_SIZE,
321 PROT_READ | PROT_WRITE | PROT_EXEC,
322 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
323 if (stack == MAP_FAILED) {
324 err = -errno;
325 printk(UM_KERN_ERR "start_userspace : mmap failed, "
326 "errno = %d\n", errno);
327 return err;
328 }
329
330 /* set stack pointer to the end of the stack page, so it can grow downwards */
331 sp = (unsigned long)stack + UM_KERN_PAGE_SIZE;
332
333 flags = CLONE_FILES | SIGCHLD;
334
335 /* clone into new userspace process */
336 pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
337 if (pid < 0) {
338 err = -errno;
339 printk(UM_KERN_ERR "start_userspace : clone failed, "
340 "errno = %d\n", errno);
341 return err;
342 }
343
344 do {
345 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
346 if (n < 0) {
347 err = -errno;
348 printk(UM_KERN_ERR "start_userspace : wait failed, "
349 "errno = %d\n", errno);
350 goto out_kill;
351 }
352 } while (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGALRM));
353
354 if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) {
355 err = -EINVAL;
356 printk(UM_KERN_ERR "start_userspace : expected SIGSTOP, got "
357 "status = %d\n", status);
358 goto out_kill;
359 }
360
361 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
362 (void *) PTRACE_O_TRACESYSGOOD) < 0) {
363 err = -errno;
364 printk(UM_KERN_ERR "start_userspace : PTRACE_OLDSETOPTIONS "
365 "failed, errno = %d\n", errno);
366 goto out_kill;
367 }
368
369 if (munmap(stack, UM_KERN_PAGE_SIZE) < 0) {
370 err = -errno;
371 printk(UM_KERN_ERR "start_userspace : munmap failed, "
372 "errno = %d\n", errno);
373 goto out_kill;
374 }
375
376 return pid;
377
378 out_kill:
379 os_kill_ptraced_process(pid, 1);
380 return err;
381}
382
383void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs)
384{
385 int err, status, op, pid = userspace_pid[0];
386 /* To prevent races if using_sysemu changes under us.*/
387 int local_using_sysemu;
388 siginfo_t si;
389
390 /* Handle any immediate reschedules or signals */
391 interrupt_end();
392
393 while (1) {
394 if (kill_userspace_mm[0])
395 fatal_sigsegv();
396
397 /*
398 * This can legitimately fail if the process loads a
399 * bogus value into a segment register. It will
400 * segfault and PTRACE_GETREGS will read that value
401 * out of the process. However, PTRACE_SETREGS will
402 * fail. In this case, there is nothing to do but
403 * just kill the process.
404 */
405 if (ptrace(PTRACE_SETREGS, pid, 0, regs->gp)) {
406 printk(UM_KERN_ERR "userspace - ptrace set regs "
407 "failed, errno = %d\n", errno);
408 fatal_sigsegv();
409 }
410
411 if (put_fp_registers(pid, regs->fp)) {
412 printk(UM_KERN_ERR "userspace - ptrace set fp regs "
413 "failed, errno = %d\n", errno);
414 fatal_sigsegv();
415 }
416
417 /* Now we set local_using_sysemu to be used for one loop */
418 local_using_sysemu = get_using_sysemu();
419
420 op = SELECT_PTRACE_OPERATION(local_using_sysemu,
421 singlestepping(NULL));
422
423 if (ptrace(op, pid, 0, 0)) {
424 printk(UM_KERN_ERR "userspace - ptrace continue "
425 "failed, op = %d, errno = %d\n", op, errno);
426 fatal_sigsegv();
427 }
428
429 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
430 if (err < 0) {
431 printk(UM_KERN_ERR "userspace - wait failed, "
432 "errno = %d\n", errno);
433 fatal_sigsegv();
434 }
435
436 regs->is_user = 1;
437 if (ptrace(PTRACE_GETREGS, pid, 0, regs->gp)) {
438 printk(UM_KERN_ERR "userspace - PTRACE_GETREGS failed, "
439 "errno = %d\n", errno);
440 fatal_sigsegv();
441 }
442
443 if (get_fp_registers(pid, regs->fp)) {
444 printk(UM_KERN_ERR "userspace - get_fp_registers failed, "
445 "errno = %d\n", errno);
446 fatal_sigsegv();
447 }
448
449 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
450
451 if (WIFSTOPPED(status)) {
452 int sig = WSTOPSIG(status);
453
454 /* These signal handlers need the si argument.
455 * The SIGIO and SIGALARM handlers which constitute the
456 * majority of invocations, do not use it.
457 */
458 switch (sig) {
459 case SIGSEGV:
460 case SIGTRAP:
461 case SIGILL:
462 case SIGBUS:
463 case SIGFPE:
464 case SIGWINCH:
465 ptrace(PTRACE_GETSIGINFO, pid, 0, (struct siginfo *)&si);
466 break;
467 }
468
469 switch (sig) {
470 case SIGSEGV:
471 if (PTRACE_FULL_FAULTINFO) {
472 get_skas_faultinfo(pid,
473 ®s->faultinfo, aux_fp_regs);
474 (*sig_info[SIGSEGV])(SIGSEGV, (struct siginfo *)&si,
475 regs);
476 }
477 else handle_segv(pid, regs, aux_fp_regs);
478 break;
479 case SIGTRAP + 0x80:
480 handle_trap(pid, regs, local_using_sysemu);
481 break;
482 case SIGTRAP:
483 relay_signal(SIGTRAP, (struct siginfo *)&si, regs);
484 break;
485 case SIGALRM:
486 break;
487 case SIGIO:
488 case SIGILL:
489 case SIGBUS:
490 case SIGFPE:
491 case SIGWINCH:
492 block_signals_trace();
493 (*sig_info[sig])(sig, (struct siginfo *)&si, regs);
494 unblock_signals_trace();
495 break;
496 default:
497 printk(UM_KERN_ERR "userspace - child stopped "
498 "with signal %d\n", sig);
499 fatal_sigsegv();
500 }
501 pid = userspace_pid[0];
502 interrupt_end();
503
504 /* Avoid -ERESTARTSYS handling in host */
505 if (PT_SYSCALL_NR_OFFSET != PT_SYSCALL_RET_OFFSET)
506 PT_SYSCALL_NR(regs->gp) = -1;
507 }
508 }
509}
510
511static unsigned long thread_regs[MAX_REG_NR];
512static unsigned long thread_fp_regs[FP_SIZE];
513
514static int __init init_thread_regs(void)
515{
516 get_safe_registers(thread_regs, thread_fp_regs);
517 /* Set parent's instruction pointer to start of clone-stub */
518 thread_regs[REGS_IP_INDEX] = STUB_CODE +
519 (unsigned long) stub_clone_handler -
520 (unsigned long) __syscall_stub_start;
521 thread_regs[REGS_SP_INDEX] = STUB_DATA + UM_KERN_PAGE_SIZE -
522 sizeof(void *);
523#ifdef __SIGNAL_FRAMESIZE
524 thread_regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
525#endif
526 return 0;
527}
528
529__initcall(init_thread_regs);
530
531int copy_context_skas0(unsigned long new_stack, int pid)
532{
533 int err;
534 unsigned long current_stack = current_stub_stack();
535 struct stub_data *data = (struct stub_data *) current_stack;
536 struct stub_data *child_data = (struct stub_data *) new_stack;
537 unsigned long long new_offset;
538 int new_fd = phys_mapping(uml_to_phys((void *)new_stack), &new_offset);
539
540 /*
541 * prepare offset and fd of child's stack as argument for parent's
542 * and child's mmap2 calls
543 */
544 *data = ((struct stub_data) {
545 .offset = MMAP_OFFSET(new_offset),
546 .fd = new_fd,
547 .parent_err = -ESRCH,
548 .child_err = 0,
549 });
550
551 *child_data = ((struct stub_data) {
552 .child_err = -ESRCH,
553 });
554
555 err = ptrace_setregs(pid, thread_regs);
556 if (err < 0) {
557 err = -errno;
558 printk(UM_KERN_ERR "copy_context_skas0 : PTRACE_SETREGS "
559 "failed, pid = %d, errno = %d\n", pid, -err);
560 return err;
561 }
562
563 err = put_fp_registers(pid, thread_fp_regs);
564 if (err < 0) {
565 printk(UM_KERN_ERR "copy_context_skas0 : put_fp_registers "
566 "failed, pid = %d, err = %d\n", pid, err);
567 return err;
568 }
569
570 /*
571 * Wait, until parent has finished its work: read child's pid from
572 * parent's stack, and check, if bad result.
573 */
574 err = ptrace(PTRACE_CONT, pid, 0, 0);
575 if (err) {
576 err = -errno;
577 printk(UM_KERN_ERR "Failed to continue new process, pid = %d, "
578 "errno = %d\n", pid, errno);
579 return err;
580 }
581
582 wait_stub_done(pid);
583
584 pid = data->parent_err;
585 if (pid < 0) {
586 printk(UM_KERN_ERR "copy_context_skas0 - stub-parent reports "
587 "error %d\n", -pid);
588 return pid;
589 }
590
591 /*
592 * Wait, until child has finished too: read child's result from
593 * child's stack and check it.
594 */
595 wait_stub_done(pid);
596 if (child_data->child_err != STUB_DATA) {
597 printk(UM_KERN_ERR "copy_context_skas0 - stub-child %d reports "
598 "error %ld\n", pid, data->child_err);
599 err = data->child_err;
600 goto out_kill;
601 }
602
603 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
604 (void *)PTRACE_O_TRACESYSGOOD) < 0) {
605 err = -errno;
606 printk(UM_KERN_ERR "copy_context_skas0 : PTRACE_OLDSETOPTIONS "
607 "failed, errno = %d\n", errno);
608 goto out_kill;
609 }
610
611 return pid;
612
613 out_kill:
614 os_kill_ptraced_process(pid, 1);
615 return err;
616}
617
618void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
619{
620 (*buf)[0].JB_IP = (unsigned long) handler;
621 (*buf)[0].JB_SP = (unsigned long) stack + UM_THREAD_SIZE -
622 sizeof(void *);
623}
624
625#define INIT_JMP_NEW_THREAD 0
626#define INIT_JMP_CALLBACK 1
627#define INIT_JMP_HALT 2
628#define INIT_JMP_REBOOT 3
629
630void switch_threads(jmp_buf *me, jmp_buf *you)
631{
632 if (UML_SETJMP(me) == 0)
633 UML_LONGJMP(you, 1);
634}
635
636static jmp_buf initial_jmpbuf;
637
638/* XXX Make these percpu */
639static void (*cb_proc)(void *arg);
640static void *cb_arg;
641static jmp_buf *cb_back;
642
643int start_idle_thread(void *stack, jmp_buf *switch_buf)
644{
645 int n;
646
647 set_handler(SIGWINCH);
648
649 /*
650 * Can't use UML_SETJMP or UML_LONGJMP here because they save
651 * and restore signals, with the possible side-effect of
652 * trying to handle any signals which came when they were
653 * blocked, which can't be done on this stack.
654 * Signals must be blocked when jumping back here and restored
655 * after returning to the jumper.
656 */
657 n = setjmp(initial_jmpbuf);
658 switch (n) {
659 case INIT_JMP_NEW_THREAD:
660 (*switch_buf)[0].JB_IP = (unsigned long) uml_finishsetup;
661 (*switch_buf)[0].JB_SP = (unsigned long) stack +
662 UM_THREAD_SIZE - sizeof(void *);
663 break;
664 case INIT_JMP_CALLBACK:
665 (*cb_proc)(cb_arg);
666 longjmp(*cb_back, 1);
667 break;
668 case INIT_JMP_HALT:
669 kmalloc_ok = 0;
670 return 0;
671 case INIT_JMP_REBOOT:
672 kmalloc_ok = 0;
673 return 1;
674 default:
675 printk(UM_KERN_ERR "Bad sigsetjmp return in "
676 "start_idle_thread - %d\n", n);
677 fatal_sigsegv();
678 }
679 longjmp(*switch_buf, 1);
680
681 /* unreachable */
682 printk(UM_KERN_ERR "impossible long jump!");
683 fatal_sigsegv();
684 return 0;
685}
686
687void initial_thread_cb_skas(void (*proc)(void *), void *arg)
688{
689 jmp_buf here;
690
691 cb_proc = proc;
692 cb_arg = arg;
693 cb_back = &here;
694
695 block_signals_trace();
696 if (UML_SETJMP(&here) == 0)
697 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK);
698 unblock_signals_trace();
699
700 cb_proc = NULL;
701 cb_arg = NULL;
702 cb_back = NULL;
703}
704
705void halt_skas(void)
706{
707 block_signals_trace();
708 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT);
709}
710
711static bool noreboot;
712
713static int __init noreboot_cmd_param(char *str, int *add)
714{
715 noreboot = true;
716 return 0;
717}
718
719__uml_setup("noreboot", noreboot_cmd_param,
720"noreboot\n"
721" Rather than rebooting, exit always, akin to QEMU's -no-reboot option.\n"
722" This is useful if you're using CONFIG_PANIC_TIMEOUT in order to catch\n"
723" crashes in CI\n");
724
725void reboot_skas(void)
726{
727 block_signals_trace();
728 UML_LONGJMP(&initial_jmpbuf, noreboot ? INIT_JMP_HALT : INIT_JMP_REBOOT);
729}
730
731void __switch_mm(struct mm_id *mm_idp)
732{
733 userspace_pid[0] = mm_idp->u.pid;
734 kill_userspace_mm[0] = mm_idp->kill;
735}
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 <unistd.h>
9#include <sched.h>
10#include <errno.h>
11#include <string.h>
12#include <sys/mman.h>
13#include <sys/wait.h>
14#include <asm/unistd.h>
15#include <as-layout.h>
16#include <init.h>
17#include <kern_util.h>
18#include <mem.h>
19#include <os.h>
20#include <ptrace_user.h>
21#include <registers.h>
22#include <skas.h>
23#include <sysdep/stub.h>
24#include <linux/threads.h>
25
26int is_skas_winch(int pid, int fd, void *data)
27{
28 return pid == getpgrp();
29}
30
31static const char *ptrace_reg_name(int idx)
32{
33#define R(n) case HOST_##n: return #n
34
35 switch (idx) {
36#ifdef __x86_64__
37 R(BX);
38 R(CX);
39 R(DI);
40 R(SI);
41 R(DX);
42 R(BP);
43 R(AX);
44 R(R8);
45 R(R9);
46 R(R10);
47 R(R11);
48 R(R12);
49 R(R13);
50 R(R14);
51 R(R15);
52 R(ORIG_AX);
53 R(CS);
54 R(SS);
55 R(EFLAGS);
56#elif defined(__i386__)
57 R(IP);
58 R(SP);
59 R(EFLAGS);
60 R(AX);
61 R(BX);
62 R(CX);
63 R(DX);
64 R(SI);
65 R(DI);
66 R(BP);
67 R(CS);
68 R(SS);
69 R(DS);
70 R(FS);
71 R(ES);
72 R(GS);
73 R(ORIG_AX);
74#endif
75 }
76 return "";
77}
78
79static int ptrace_dump_regs(int pid)
80{
81 unsigned long regs[MAX_REG_NR];
82 int i;
83
84 if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
85 return -errno;
86
87 printk(UM_KERN_ERR "Stub registers -\n");
88 for (i = 0; i < ARRAY_SIZE(regs); i++) {
89 const char *regname = ptrace_reg_name(i);
90
91 printk(UM_KERN_ERR "\t%s\t(%2d): %lx\n", regname, i, regs[i]);
92 }
93
94 return 0;
95}
96
97/*
98 * Signals that are OK to receive in the stub - we'll just continue it.
99 * SIGWINCH will happen when UML is inside a detached screen.
100 */
101#define STUB_SIG_MASK ((1 << SIGALRM) | (1 << SIGWINCH))
102
103/* Signals that the stub will finish with - anything else is an error */
104#define STUB_DONE_MASK (1 << SIGTRAP)
105
106void wait_stub_done(int pid)
107{
108 int n, status, err;
109
110 while (1) {
111 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
112 if ((n < 0) || !WIFSTOPPED(status))
113 goto bad_wait;
114
115 if (((1 << WSTOPSIG(status)) & STUB_SIG_MASK) == 0)
116 break;
117
118 err = ptrace(PTRACE_CONT, pid, 0, 0);
119 if (err) {
120 printk(UM_KERN_ERR "wait_stub_done : continue failed, "
121 "errno = %d\n", errno);
122 fatal_sigsegv();
123 }
124 }
125
126 if (((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0)
127 return;
128
129bad_wait:
130 err = ptrace_dump_regs(pid);
131 if (err)
132 printk(UM_KERN_ERR "Failed to get registers from stub, "
133 "errno = %d\n", -err);
134 printk(UM_KERN_ERR "wait_stub_done : failed to wait for SIGTRAP, "
135 "pid = %d, n = %d, errno = %d, status = 0x%x\n", pid, n, errno,
136 status);
137 fatal_sigsegv();
138}
139
140extern unsigned long current_stub_stack(void);
141
142static void get_skas_faultinfo(int pid, struct faultinfo *fi, unsigned long *aux_fp_regs)
143{
144 int err;
145
146 err = get_fp_registers(pid, aux_fp_regs);
147 if (err < 0) {
148 printk(UM_KERN_ERR "save_fp_registers returned %d\n",
149 err);
150 fatal_sigsegv();
151 }
152 err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV);
153 if (err) {
154 printk(UM_KERN_ERR "Failed to continue stub, pid = %d, "
155 "errno = %d\n", pid, errno);
156 fatal_sigsegv();
157 }
158 wait_stub_done(pid);
159
160 /*
161 * faultinfo is prepared by the stub_segv_handler at start of
162 * the stub stack page. We just have to copy it.
163 */
164 memcpy(fi, (void *)current_stub_stack(), sizeof(*fi));
165
166 err = put_fp_registers(pid, aux_fp_regs);
167 if (err < 0) {
168 printk(UM_KERN_ERR "put_fp_registers returned %d\n",
169 err);
170 fatal_sigsegv();
171 }
172}
173
174static void handle_segv(int pid, struct uml_pt_regs *regs, unsigned long *aux_fp_regs)
175{
176 get_skas_faultinfo(pid, ®s->faultinfo, aux_fp_regs);
177 segv(regs->faultinfo, 0, 1, NULL);
178}
179
180/*
181 * To use the same value of using_sysemu as the caller, ask it that value
182 * (in local_using_sysemu
183 */
184static void handle_trap(int pid, struct uml_pt_regs *regs,
185 int local_using_sysemu)
186{
187 int err, status;
188
189 if ((UPT_IP(regs) >= STUB_START) && (UPT_IP(regs) < STUB_END))
190 fatal_sigsegv();
191
192 if (!local_using_sysemu)
193 {
194 err = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET,
195 __NR_getpid);
196 if (err < 0) {
197 printk(UM_KERN_ERR "handle_trap - nullifying syscall "
198 "failed, errno = %d\n", errno);
199 fatal_sigsegv();
200 }
201
202 err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
203 if (err < 0) {
204 printk(UM_KERN_ERR "handle_trap - continuing to end of "
205 "syscall failed, errno = %d\n", errno);
206 fatal_sigsegv();
207 }
208
209 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
210 if ((err < 0) || !WIFSTOPPED(status) ||
211 (WSTOPSIG(status) != SIGTRAP + 0x80)) {
212 err = ptrace_dump_regs(pid);
213 if (err)
214 printk(UM_KERN_ERR "Failed to get registers "
215 "from process, errno = %d\n", -err);
216 printk(UM_KERN_ERR "handle_trap - failed to wait at "
217 "end of syscall, errno = %d, status = %d\n",
218 errno, status);
219 fatal_sigsegv();
220 }
221 }
222
223 handle_syscall(regs);
224}
225
226extern char __syscall_stub_start[];
227
228/**
229 * userspace_tramp() - userspace trampoline
230 * @stack: pointer to the new userspace stack page, can be NULL, if? FIXME:
231 *
232 * The userspace trampoline is used to setup a new userspace process in start_userspace() after it was clone()'ed.
233 * This function will run on a temporary stack page.
234 * It ptrace()'es itself, then
235 * Two pages are mapped into the userspace address space:
236 * - STUB_CODE (with EXEC), which contains the skas stub code
237 * - 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.
238 * Also for the userspace process a SIGSEGV handler is installed to catch pagefaults in the userspace process.
239 * And last the process stops itself to give control to the UML kernel for this userspace process.
240 *
241 * Return: Always zero, otherwise the current userspace process is ended with non null exit() call
242 */
243static int userspace_tramp(void *stack)
244{
245 void *addr;
246 int fd;
247 unsigned long long offset;
248
249 ptrace(PTRACE_TRACEME, 0, 0, 0);
250
251 signal(SIGTERM, SIG_DFL);
252 signal(SIGWINCH, SIG_IGN);
253
254 fd = phys_mapping(to_phys(__syscall_stub_start), &offset);
255 addr = mmap64((void *) STUB_CODE, UM_KERN_PAGE_SIZE,
256 PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
257 if (addr == MAP_FAILED) {
258 printk(UM_KERN_ERR "mapping mmap stub at 0x%lx failed, "
259 "errno = %d\n", STUB_CODE, errno);
260 exit(1);
261 }
262
263 if (stack != NULL) {
264 fd = phys_mapping(to_phys(stack), &offset);
265 addr = mmap((void *) STUB_DATA,
266 UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
267 MAP_FIXED | MAP_SHARED, fd, offset);
268 if (addr == MAP_FAILED) {
269 printk(UM_KERN_ERR "mapping segfault stack "
270 "at 0x%lx failed, errno = %d\n",
271 STUB_DATA, errno);
272 exit(1);
273 }
274 }
275 if (stack != NULL) {
276 struct sigaction sa;
277
278 unsigned long v = STUB_CODE +
279 (unsigned long) stub_segv_handler -
280 (unsigned long) __syscall_stub_start;
281
282 set_sigstack((void *) STUB_DATA, UM_KERN_PAGE_SIZE);
283 sigemptyset(&sa.sa_mask);
284 sa.sa_flags = SA_ONSTACK | SA_NODEFER | SA_SIGINFO;
285 sa.sa_sigaction = (void *) v;
286 sa.sa_restorer = NULL;
287 if (sigaction(SIGSEGV, &sa, NULL) < 0) {
288 printk(UM_KERN_ERR "userspace_tramp - setting SIGSEGV "
289 "handler failed - errno = %d\n", errno);
290 exit(1);
291 }
292 }
293
294 kill(os_getpid(), SIGSTOP);
295 return 0;
296}
297
298int userspace_pid[NR_CPUS];
299int kill_userspace_mm[NR_CPUS];
300
301/**
302 * start_userspace() - prepare a new userspace process
303 * @stub_stack: pointer to the stub stack. Can be NULL, if? FIXME:
304 *
305 * Setups a new temporary stack page that is used while userspace_tramp() runs
306 * Clones the kernel process into a new userspace process, with FDs only.
307 *
308 * Return: When positive: the process id of the new userspace process,
309 * when negative: an error number.
310 * FIXME: can PIDs become negative?!
311 */
312int start_userspace(unsigned long stub_stack)
313{
314 void *stack;
315 unsigned long sp;
316 int pid, status, n, flags, err;
317
318 /* setup a temporary stack page */
319 stack = mmap(NULL, UM_KERN_PAGE_SIZE,
320 PROT_READ | PROT_WRITE | PROT_EXEC,
321 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
322 if (stack == MAP_FAILED) {
323 err = -errno;
324 printk(UM_KERN_ERR "start_userspace : mmap failed, "
325 "errno = %d\n", errno);
326 return err;
327 }
328
329 /* set stack pointer to the end of the stack page, so it can grow downwards */
330 sp = (unsigned long)stack + UM_KERN_PAGE_SIZE;
331
332 flags = CLONE_FILES | SIGCHLD;
333
334 /* clone into new userspace process */
335 pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
336 if (pid < 0) {
337 err = -errno;
338 printk(UM_KERN_ERR "start_userspace : clone failed, "
339 "errno = %d\n", errno);
340 return err;
341 }
342
343 do {
344 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
345 if (n < 0) {
346 err = -errno;
347 printk(UM_KERN_ERR "start_userspace : wait failed, "
348 "errno = %d\n", errno);
349 goto out_kill;
350 }
351 } while (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGALRM));
352
353 if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) {
354 err = -EINVAL;
355 printk(UM_KERN_ERR "start_userspace : expected SIGSTOP, got "
356 "status = %d\n", status);
357 goto out_kill;
358 }
359
360 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
361 (void *) PTRACE_O_TRACESYSGOOD) < 0) {
362 err = -errno;
363 printk(UM_KERN_ERR "start_userspace : PTRACE_OLDSETOPTIONS "
364 "failed, errno = %d\n", errno);
365 goto out_kill;
366 }
367
368 if (munmap(stack, UM_KERN_PAGE_SIZE) < 0) {
369 err = -errno;
370 printk(UM_KERN_ERR "start_userspace : munmap failed, "
371 "errno = %d\n", errno);
372 goto out_kill;
373 }
374
375 return pid;
376
377 out_kill:
378 os_kill_ptraced_process(pid, 1);
379 return err;
380}
381
382void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs)
383{
384 int err, status, op, pid = userspace_pid[0];
385 /* To prevent races if using_sysemu changes under us.*/
386 int local_using_sysemu;
387 siginfo_t si;
388
389 /* Handle any immediate reschedules or signals */
390 interrupt_end();
391
392 while (1) {
393 if (kill_userspace_mm[0])
394 fatal_sigsegv();
395
396 /*
397 * This can legitimately fail if the process loads a
398 * bogus value into a segment register. It will
399 * segfault and PTRACE_GETREGS will read that value
400 * out of the process. However, PTRACE_SETREGS will
401 * fail. In this case, there is nothing to do but
402 * just kill the process.
403 */
404 if (ptrace(PTRACE_SETREGS, pid, 0, regs->gp)) {
405 printk(UM_KERN_ERR "userspace - ptrace set regs "
406 "failed, errno = %d\n", errno);
407 fatal_sigsegv();
408 }
409
410 if (put_fp_registers(pid, regs->fp)) {
411 printk(UM_KERN_ERR "userspace - ptrace set fp regs "
412 "failed, errno = %d\n", errno);
413 fatal_sigsegv();
414 }
415
416 /* Now we set local_using_sysemu to be used for one loop */
417 local_using_sysemu = get_using_sysemu();
418
419 op = SELECT_PTRACE_OPERATION(local_using_sysemu,
420 singlestepping(NULL));
421
422 if (ptrace(op, pid, 0, 0)) {
423 printk(UM_KERN_ERR "userspace - ptrace continue "
424 "failed, op = %d, errno = %d\n", op, errno);
425 fatal_sigsegv();
426 }
427
428 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
429 if (err < 0) {
430 printk(UM_KERN_ERR "userspace - wait failed, "
431 "errno = %d\n", errno);
432 fatal_sigsegv();
433 }
434
435 regs->is_user = 1;
436 if (ptrace(PTRACE_GETREGS, pid, 0, regs->gp)) {
437 printk(UM_KERN_ERR "userspace - PTRACE_GETREGS failed, "
438 "errno = %d\n", errno);
439 fatal_sigsegv();
440 }
441
442 if (get_fp_registers(pid, regs->fp)) {
443 printk(UM_KERN_ERR "userspace - get_fp_registers failed, "
444 "errno = %d\n", errno);
445 fatal_sigsegv();
446 }
447
448 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
449
450 if (WIFSTOPPED(status)) {
451 int sig = WSTOPSIG(status);
452
453 /* These signal handlers need the si argument.
454 * The SIGIO and SIGALARM handlers which constitute the
455 * majority of invocations, do not use it.
456 */
457 switch (sig) {
458 case SIGSEGV:
459 case SIGTRAP:
460 case SIGILL:
461 case SIGBUS:
462 case SIGFPE:
463 case SIGWINCH:
464 ptrace(PTRACE_GETSIGINFO, pid, 0, (struct siginfo *)&si);
465 break;
466 }
467
468 switch (sig) {
469 case SIGSEGV:
470 if (PTRACE_FULL_FAULTINFO) {
471 get_skas_faultinfo(pid,
472 ®s->faultinfo, aux_fp_regs);
473 (*sig_info[SIGSEGV])(SIGSEGV, (struct siginfo *)&si,
474 regs);
475 }
476 else handle_segv(pid, regs, aux_fp_regs);
477 break;
478 case SIGTRAP + 0x80:
479 handle_trap(pid, regs, local_using_sysemu);
480 break;
481 case SIGTRAP:
482 relay_signal(SIGTRAP, (struct siginfo *)&si, regs);
483 break;
484 case SIGALRM:
485 break;
486 case SIGIO:
487 case SIGILL:
488 case SIGBUS:
489 case SIGFPE:
490 case SIGWINCH:
491 block_signals_trace();
492 (*sig_info[sig])(sig, (struct siginfo *)&si, regs);
493 unblock_signals_trace();
494 break;
495 default:
496 printk(UM_KERN_ERR "userspace - child stopped "
497 "with signal %d\n", sig);
498 fatal_sigsegv();
499 }
500 pid = userspace_pid[0];
501 interrupt_end();
502
503 /* Avoid -ERESTARTSYS handling in host */
504 if (PT_SYSCALL_NR_OFFSET != PT_SYSCALL_RET_OFFSET)
505 PT_SYSCALL_NR(regs->gp) = -1;
506 }
507 }
508}
509
510static unsigned long thread_regs[MAX_REG_NR];
511static unsigned long thread_fp_regs[FP_SIZE];
512
513static int __init init_thread_regs(void)
514{
515 get_safe_registers(thread_regs, thread_fp_regs);
516 /* Set parent's instruction pointer to start of clone-stub */
517 thread_regs[REGS_IP_INDEX] = STUB_CODE +
518 (unsigned long) stub_clone_handler -
519 (unsigned long) __syscall_stub_start;
520 thread_regs[REGS_SP_INDEX] = STUB_DATA + UM_KERN_PAGE_SIZE -
521 sizeof(void *);
522#ifdef __SIGNAL_FRAMESIZE
523 thread_regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
524#endif
525 return 0;
526}
527
528__initcall(init_thread_regs);
529
530int copy_context_skas0(unsigned long new_stack, int pid)
531{
532 int err;
533 unsigned long current_stack = current_stub_stack();
534 struct stub_data *data = (struct stub_data *) current_stack;
535 struct stub_data *child_data = (struct stub_data *) new_stack;
536 unsigned long long new_offset;
537 int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset);
538
539 /*
540 * prepare offset and fd of child's stack as argument for parent's
541 * and child's mmap2 calls
542 */
543 *data = ((struct stub_data) {
544 .offset = MMAP_OFFSET(new_offset),
545 .fd = new_fd,
546 .parent_err = -ESRCH,
547 .child_err = 0,
548 });
549
550 *child_data = ((struct stub_data) {
551 .child_err = -ESRCH,
552 });
553
554 err = ptrace_setregs(pid, thread_regs);
555 if (err < 0) {
556 err = -errno;
557 printk(UM_KERN_ERR "copy_context_skas0 : PTRACE_SETREGS "
558 "failed, pid = %d, errno = %d\n", pid, -err);
559 return err;
560 }
561
562 err = put_fp_registers(pid, thread_fp_regs);
563 if (err < 0) {
564 printk(UM_KERN_ERR "copy_context_skas0 : put_fp_registers "
565 "failed, pid = %d, err = %d\n", pid, err);
566 return err;
567 }
568
569 /*
570 * Wait, until parent has finished its work: read child's pid from
571 * parent's stack, and check, if bad result.
572 */
573 err = ptrace(PTRACE_CONT, pid, 0, 0);
574 if (err) {
575 err = -errno;
576 printk(UM_KERN_ERR "Failed to continue new process, pid = %d, "
577 "errno = %d\n", pid, errno);
578 return err;
579 }
580
581 wait_stub_done(pid);
582
583 pid = data->parent_err;
584 if (pid < 0) {
585 printk(UM_KERN_ERR "copy_context_skas0 - stub-parent reports "
586 "error %d\n", -pid);
587 return pid;
588 }
589
590 /*
591 * Wait, until child has finished too: read child's result from
592 * child's stack and check it.
593 */
594 wait_stub_done(pid);
595 if (child_data->child_err != STUB_DATA) {
596 printk(UM_KERN_ERR "copy_context_skas0 - stub-child %d reports "
597 "error %ld\n", pid, data->child_err);
598 err = data->child_err;
599 goto out_kill;
600 }
601
602 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
603 (void *)PTRACE_O_TRACESYSGOOD) < 0) {
604 err = -errno;
605 printk(UM_KERN_ERR "copy_context_skas0 : PTRACE_OLDSETOPTIONS "
606 "failed, errno = %d\n", errno);
607 goto out_kill;
608 }
609
610 return pid;
611
612 out_kill:
613 os_kill_ptraced_process(pid, 1);
614 return err;
615}
616
617void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
618{
619 (*buf)[0].JB_IP = (unsigned long) handler;
620 (*buf)[0].JB_SP = (unsigned long) stack + UM_THREAD_SIZE -
621 sizeof(void *);
622}
623
624#define INIT_JMP_NEW_THREAD 0
625#define INIT_JMP_CALLBACK 1
626#define INIT_JMP_HALT 2
627#define INIT_JMP_REBOOT 3
628
629void switch_threads(jmp_buf *me, jmp_buf *you)
630{
631 if (UML_SETJMP(me) == 0)
632 UML_LONGJMP(you, 1);
633}
634
635static jmp_buf initial_jmpbuf;
636
637/* XXX Make these percpu */
638static void (*cb_proc)(void *arg);
639static void *cb_arg;
640static jmp_buf *cb_back;
641
642int start_idle_thread(void *stack, jmp_buf *switch_buf)
643{
644 int n;
645
646 set_handler(SIGWINCH);
647
648 /*
649 * Can't use UML_SETJMP or UML_LONGJMP here because they save
650 * and restore signals, with the possible side-effect of
651 * trying to handle any signals which came when they were
652 * blocked, which can't be done on this stack.
653 * Signals must be blocked when jumping back here and restored
654 * after returning to the jumper.
655 */
656 n = setjmp(initial_jmpbuf);
657 switch (n) {
658 case INIT_JMP_NEW_THREAD:
659 (*switch_buf)[0].JB_IP = (unsigned long) uml_finishsetup;
660 (*switch_buf)[0].JB_SP = (unsigned long) stack +
661 UM_THREAD_SIZE - sizeof(void *);
662 break;
663 case INIT_JMP_CALLBACK:
664 (*cb_proc)(cb_arg);
665 longjmp(*cb_back, 1);
666 break;
667 case INIT_JMP_HALT:
668 kmalloc_ok = 0;
669 return 0;
670 case INIT_JMP_REBOOT:
671 kmalloc_ok = 0;
672 return 1;
673 default:
674 printk(UM_KERN_ERR "Bad sigsetjmp return in "
675 "start_idle_thread - %d\n", n);
676 fatal_sigsegv();
677 }
678 longjmp(*switch_buf, 1);
679
680 /* unreachable */
681 printk(UM_KERN_ERR "impossible long jump!");
682 fatal_sigsegv();
683 return 0;
684}
685
686void initial_thread_cb_skas(void (*proc)(void *), void *arg)
687{
688 jmp_buf here;
689
690 cb_proc = proc;
691 cb_arg = arg;
692 cb_back = &here;
693
694 block_signals_trace();
695 if (UML_SETJMP(&here) == 0)
696 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK);
697 unblock_signals_trace();
698
699 cb_proc = NULL;
700 cb_arg = NULL;
701 cb_back = NULL;
702}
703
704void halt_skas(void)
705{
706 block_signals_trace();
707 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT);
708}
709
710void reboot_skas(void)
711{
712 block_signals_trace();
713 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_REBOOT);
714}
715
716void __switch_mm(struct mm_id *mm_idp)
717{
718 userspace_pid[0] = mm_idp->u.pid;
719 kill_userspace_mm[0] = mm_idp->kill;
720}