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_reg_name(int idx)32 static 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
ptrace_dump_regs(int pid)80 static 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
wait_stub_done(int pid)107 void 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 "%s : continue failed, errno = %d\n",
122 __func__, errno);
123 fatal_sigsegv();
124 }
125 }
126
127 if (((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0)
128 return;
129
130 bad_wait:
131 err = ptrace_dump_regs(pid);
132 if (err)
133 printk(UM_KERN_ERR "Failed to get registers from stub, errno = %d\n",
134 -err);
135 printk(UM_KERN_ERR "%s : failed to wait for SIGTRAP, pid = %d, n = %d, errno = %d, status = 0x%x\n",
136 __func__, pid, n, errno, status);
137 fatal_sigsegv();
138 }
139
140 extern unsigned long current_stub_stack(void);
141
get_skas_faultinfo(int pid,struct faultinfo * fi,unsigned long * aux_fp_regs)142 static 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
handle_segv(int pid,struct uml_pt_regs * regs,unsigned long * aux_fp_regs)174 static 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 */
handle_trap(int pid,struct uml_pt_regs * regs,int local_using_sysemu)184 static 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 "%s - nullifying syscall failed, errno = %d\n",
198 __func__, errno);
199 fatal_sigsegv();
200 }
201
202 err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
203 if (err < 0) {
204 printk(UM_KERN_ERR "%s - continuing to end of syscall failed, errno = %d\n",
205 __func__, 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 from process, errno = %d\n",
215 -err);
216 printk(UM_KERN_ERR "%s - failed to wait at end of syscall, errno = %d, status = %d\n",
217 __func__, errno, status);
218 fatal_sigsegv();
219 }
220 }
221
222 handle_syscall(regs);
223 }
224
225 extern char __syscall_stub_start[];
226
227 /**
228 * userspace_tramp() - userspace trampoline
229 * @stack: pointer to the new userspace stack page, can be NULL, if? FIXME:
230 *
231 * The userspace trampoline is used to setup a new userspace process in start_userspace() after it was clone()'ed.
232 * This function will run on a temporary stack page.
233 * It ptrace()'es itself, then
234 * Two pages are mapped into the userspace address space:
235 * - STUB_CODE (with EXEC), which contains the skas stub code
236 * - 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.
237 * Also for the userspace process a SIGSEGV handler is installed to catch pagefaults in the userspace process.
238 * And last the process stops itself to give control to the UML kernel for this userspace process.
239 *
240 * Return: Always zero, otherwise the current userspace process is ended with non null exit() call
241 */
userspace_tramp(void * stack)242 static int userspace_tramp(void *stack)
243 {
244 void *addr;
245 int fd;
246 unsigned long long offset;
247
248 ptrace(PTRACE_TRACEME, 0, 0, 0);
249
250 signal(SIGTERM, SIG_DFL);
251 signal(SIGWINCH, SIG_IGN);
252
253 fd = phys_mapping(uml_to_phys(__syscall_stub_start), &offset);
254 addr = mmap64((void *) STUB_CODE, UM_KERN_PAGE_SIZE,
255 PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
256 if (addr == MAP_FAILED) {
257 printk(UM_KERN_ERR "mapping mmap stub at 0x%lx failed, errno = %d\n",
258 STUB_CODE, errno);
259 exit(1);
260 }
261
262 if (stack != NULL) {
263 fd = phys_mapping(uml_to_phys(stack), &offset);
264 addr = mmap((void *) STUB_DATA,
265 STUB_DATA_PAGES * UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
266 MAP_FIXED | MAP_SHARED, fd, offset);
267 if (addr == MAP_FAILED) {
268 printk(UM_KERN_ERR "mapping segfault stack at 0x%lx failed, errno = %d\n",
269 STUB_DATA, errno);
270 exit(1);
271 }
272 }
273 if (stack != NULL) {
274 struct sigaction sa;
275
276 unsigned long v = STUB_CODE +
277 (unsigned long) stub_segv_handler -
278 (unsigned long) __syscall_stub_start;
279
280 set_sigstack((void *) STUB_DATA, STUB_DATA_PAGES * UM_KERN_PAGE_SIZE);
281 sigemptyset(&sa.sa_mask);
282 sa.sa_flags = SA_ONSTACK | SA_NODEFER | SA_SIGINFO;
283 sa.sa_sigaction = (void *) v;
284 sa.sa_restorer = NULL;
285 if (sigaction(SIGSEGV, &sa, NULL) < 0) {
286 printk(UM_KERN_ERR "%s - setting SIGSEGV handler failed - errno = %d\n",
287 __func__, errno);
288 exit(1);
289 }
290 }
291
292 kill(os_getpid(), SIGSTOP);
293 return 0;
294 }
295
296 int userspace_pid[NR_CPUS];
297 int kill_userspace_mm[NR_CPUS];
298
299 /**
300 * start_userspace() - prepare a new userspace process
301 * @stub_stack: pointer to the stub stack. Can be NULL, if? FIXME:
302 *
303 * Setups a new temporary stack page that is used while userspace_tramp() runs
304 * Clones the kernel process into a new userspace process, with FDs only.
305 *
306 * Return: When positive: the process id of the new userspace process,
307 * when negative: an error number.
308 * FIXME: can PIDs become negative?!
309 */
start_userspace(unsigned long stub_stack)310 int start_userspace(unsigned long stub_stack)
311 {
312 void *stack;
313 unsigned long sp;
314 int pid, status, n, flags, err;
315
316 /* setup a temporary stack page */
317 stack = mmap(NULL, UM_KERN_PAGE_SIZE,
318 PROT_READ | PROT_WRITE | PROT_EXEC,
319 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
320 if (stack == MAP_FAILED) {
321 err = -errno;
322 printk(UM_KERN_ERR "%s : mmap failed, errno = %d\n",
323 __func__, errno);
324 return err;
325 }
326
327 /* set stack pointer to the end of the stack page, so it can grow downwards */
328 sp = (unsigned long)stack + UM_KERN_PAGE_SIZE;
329
330 flags = CLONE_FILES | SIGCHLD;
331
332 /* clone into new userspace process */
333 pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
334 if (pid < 0) {
335 err = -errno;
336 printk(UM_KERN_ERR "%s : clone failed, errno = %d\n",
337 __func__, errno);
338 return err;
339 }
340
341 do {
342 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
343 if (n < 0) {
344 err = -errno;
345 printk(UM_KERN_ERR "%s : wait failed, errno = %d\n",
346 __func__, errno);
347 goto out_kill;
348 }
349 } while (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGALRM));
350
351 if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) {
352 err = -EINVAL;
353 printk(UM_KERN_ERR "%s : expected SIGSTOP, got status = %d\n",
354 __func__, status);
355 goto out_kill;
356 }
357
358 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
359 (void *) PTRACE_O_TRACESYSGOOD) < 0) {
360 err = -errno;
361 printk(UM_KERN_ERR "%s : PTRACE_OLDSETOPTIONS failed, errno = %d\n",
362 __func__, errno);
363 goto out_kill;
364 }
365
366 if (munmap(stack, UM_KERN_PAGE_SIZE) < 0) {
367 err = -errno;
368 printk(UM_KERN_ERR "%s : munmap failed, errno = %d\n",
369 __func__, errno);
370 goto out_kill;
371 }
372
373 return pid;
374
375 out_kill:
376 os_kill_ptraced_process(pid, 1);
377 return err;
378 }
379
userspace(struct uml_pt_regs * regs,unsigned long * aux_fp_regs)380 void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs)
381 {
382 int err, status, op, pid = userspace_pid[0];
383 /* To prevent races if using_sysemu changes under us.*/
384 int local_using_sysemu;
385 siginfo_t si;
386
387 /* Handle any immediate reschedules or signals */
388 interrupt_end();
389
390 while (1) {
391 if (kill_userspace_mm[0])
392 fatal_sigsegv();
393
394 /*
395 * This can legitimately fail if the process loads a
396 * bogus value into a segment register. It will
397 * segfault and PTRACE_GETREGS will read that value
398 * out of the process. However, PTRACE_SETREGS will
399 * fail. In this case, there is nothing to do but
400 * just kill the process.
401 */
402 if (ptrace(PTRACE_SETREGS, pid, 0, regs->gp)) {
403 printk(UM_KERN_ERR "%s - ptrace set regs failed, errno = %d\n",
404 __func__, errno);
405 fatal_sigsegv();
406 }
407
408 if (put_fp_registers(pid, regs->fp)) {
409 printk(UM_KERN_ERR "%s - ptrace set fp regs failed, errno = %d\n",
410 __func__, errno);
411 fatal_sigsegv();
412 }
413
414 /* Now we set local_using_sysemu to be used for one loop */
415 local_using_sysemu = get_using_sysemu();
416
417 op = SELECT_PTRACE_OPERATION(local_using_sysemu,
418 singlestepping(NULL));
419
420 if (ptrace(op, pid, 0, 0)) {
421 printk(UM_KERN_ERR "%s - ptrace continue failed, op = %d, errno = %d\n",
422 __func__, op, errno);
423 fatal_sigsegv();
424 }
425
426 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
427 if (err < 0) {
428 printk(UM_KERN_ERR "%s - wait failed, errno = %d\n",
429 __func__, errno);
430 fatal_sigsegv();
431 }
432
433 regs->is_user = 1;
434 if (ptrace(PTRACE_GETREGS, pid, 0, regs->gp)) {
435 printk(UM_KERN_ERR "%s - PTRACE_GETREGS failed, errno = %d\n",
436 __func__, errno);
437 fatal_sigsegv();
438 }
439
440 if (get_fp_registers(pid, regs->fp)) {
441 printk(UM_KERN_ERR "%s - get_fp_registers failed, errno = %d\n",
442 __func__, errno);
443 fatal_sigsegv();
444 }
445
446 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
447
448 if (WIFSTOPPED(status)) {
449 int sig = WSTOPSIG(status);
450
451 /* These signal handlers need the si argument.
452 * The SIGIO and SIGALARM handlers which constitute the
453 * majority of invocations, do not use it.
454 */
455 switch (sig) {
456 case SIGSEGV:
457 case SIGTRAP:
458 case SIGILL:
459 case SIGBUS:
460 case SIGFPE:
461 case SIGWINCH:
462 ptrace(PTRACE_GETSIGINFO, pid, 0, (struct siginfo *)&si);
463 break;
464 }
465
466 switch (sig) {
467 case SIGSEGV:
468 if (PTRACE_FULL_FAULTINFO) {
469 get_skas_faultinfo(pid,
470 ®s->faultinfo, aux_fp_regs);
471 (*sig_info[SIGSEGV])(SIGSEGV, (struct siginfo *)&si,
472 regs);
473 }
474 else handle_segv(pid, regs, aux_fp_regs);
475 break;
476 case SIGTRAP + 0x80:
477 handle_trap(pid, regs, local_using_sysemu);
478 break;
479 case SIGTRAP:
480 relay_signal(SIGTRAP, (struct siginfo *)&si, regs);
481 break;
482 case SIGALRM:
483 break;
484 case SIGIO:
485 case SIGILL:
486 case SIGBUS:
487 case SIGFPE:
488 case SIGWINCH:
489 block_signals_trace();
490 (*sig_info[sig])(sig, (struct siginfo *)&si, regs);
491 unblock_signals_trace();
492 break;
493 default:
494 printk(UM_KERN_ERR "%s - child stopped with signal %d\n",
495 __func__, sig);
496 fatal_sigsegv();
497 }
498 pid = userspace_pid[0];
499 interrupt_end();
500
501 /* Avoid -ERESTARTSYS handling in host */
502 if (PT_SYSCALL_NR_OFFSET != PT_SYSCALL_RET_OFFSET)
503 PT_SYSCALL_NR(regs->gp) = -1;
504 }
505 }
506 }
507
508 static unsigned long thread_regs[MAX_REG_NR];
509 static unsigned long thread_fp_regs[FP_SIZE];
510
init_thread_regs(void)511 static int __init init_thread_regs(void)
512 {
513 get_safe_registers(thread_regs, thread_fp_regs);
514 /* Set parent's instruction pointer to start of clone-stub */
515 thread_regs[REGS_IP_INDEX] = STUB_CODE +
516 (unsigned long) stub_clone_handler -
517 (unsigned long) __syscall_stub_start;
518 thread_regs[REGS_SP_INDEX] = STUB_DATA + STUB_DATA_PAGES * UM_KERN_PAGE_SIZE -
519 sizeof(void *);
520 #ifdef __SIGNAL_FRAMESIZE
521 thread_regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
522 #endif
523 return 0;
524 }
525
526 __initcall(init_thread_regs);
527
copy_context_skas0(unsigned long new_stack,int pid)528 int copy_context_skas0(unsigned long new_stack, int pid)
529 {
530 int err;
531 unsigned long current_stack = current_stub_stack();
532 struct stub_data *data = (struct stub_data *) current_stack;
533 struct stub_data *child_data = (struct stub_data *) new_stack;
534 unsigned long long new_offset;
535 int new_fd = phys_mapping(uml_to_phys((void *)new_stack), &new_offset);
536
537 /*
538 * prepare offset and fd of child's stack as argument for parent's
539 * and child's mmap2 calls
540 */
541 *data = ((struct stub_data) {
542 .offset = MMAP_OFFSET(new_offset),
543 .fd = new_fd,
544 .parent_err = -ESRCH,
545 .child_err = 0,
546 });
547
548 *child_data = ((struct stub_data) {
549 .child_err = -ESRCH,
550 });
551
552 err = ptrace_setregs(pid, thread_regs);
553 if (err < 0) {
554 err = -errno;
555 printk(UM_KERN_ERR "%s : PTRACE_SETREGS failed, pid = %d, errno = %d\n",
556 __func__, pid, -err);
557 return err;
558 }
559
560 err = put_fp_registers(pid, thread_fp_regs);
561 if (err < 0) {
562 printk(UM_KERN_ERR "%s : put_fp_registers failed, pid = %d, err = %d\n",
563 __func__, pid, err);
564 return err;
565 }
566
567 /*
568 * Wait, until parent has finished its work: read child's pid from
569 * parent's stack, and check, if bad result.
570 */
571 err = ptrace(PTRACE_CONT, pid, 0, 0);
572 if (err) {
573 err = -errno;
574 printk(UM_KERN_ERR "Failed to continue new process, pid = %d, errno = %d\n",
575 pid, errno);
576 return err;
577 }
578
579 wait_stub_done(pid);
580
581 pid = data->parent_err;
582 if (pid < 0) {
583 printk(UM_KERN_ERR "%s - stub-parent reports error %d\n",
584 __func__, -pid);
585 return pid;
586 }
587
588 /*
589 * Wait, until child has finished too: read child's result from
590 * child's stack and check it.
591 */
592 wait_stub_done(pid);
593 if (child_data->child_err != STUB_DATA) {
594 printk(UM_KERN_ERR "%s - stub-child %d reports error %ld\n",
595 __func__, pid, data->child_err);
596 err = data->child_err;
597 goto out_kill;
598 }
599
600 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
601 (void *)PTRACE_O_TRACESYSGOOD) < 0) {
602 err = -errno;
603 printk(UM_KERN_ERR "%s : PTRACE_OLDSETOPTIONS failed, errno = %d\n",
604 __func__, errno);
605 goto out_kill;
606 }
607
608 return pid;
609
610 out_kill:
611 os_kill_ptraced_process(pid, 1);
612 return err;
613 }
614
new_thread(void * stack,jmp_buf * buf,void (* handler)(void))615 void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
616 {
617 (*buf)[0].JB_IP = (unsigned long) handler;
618 (*buf)[0].JB_SP = (unsigned long) stack + UM_THREAD_SIZE -
619 sizeof(void *);
620 }
621
622 #define INIT_JMP_NEW_THREAD 0
623 #define INIT_JMP_CALLBACK 1
624 #define INIT_JMP_HALT 2
625 #define INIT_JMP_REBOOT 3
626
switch_threads(jmp_buf * me,jmp_buf * you)627 void switch_threads(jmp_buf *me, jmp_buf *you)
628 {
629 if (UML_SETJMP(me) == 0)
630 UML_LONGJMP(you, 1);
631 }
632
633 static jmp_buf initial_jmpbuf;
634
635 /* XXX Make these percpu */
636 static void (*cb_proc)(void *arg);
637 static void *cb_arg;
638 static jmp_buf *cb_back;
639
start_idle_thread(void * stack,jmp_buf * switch_buf)640 int start_idle_thread(void *stack, jmp_buf *switch_buf)
641 {
642 int n;
643
644 set_handler(SIGWINCH);
645
646 /*
647 * Can't use UML_SETJMP or UML_LONGJMP here because they save
648 * and restore signals, with the possible side-effect of
649 * trying to handle any signals which came when they were
650 * blocked, which can't be done on this stack.
651 * Signals must be blocked when jumping back here and restored
652 * after returning to the jumper.
653 */
654 n = setjmp(initial_jmpbuf);
655 switch (n) {
656 case INIT_JMP_NEW_THREAD:
657 (*switch_buf)[0].JB_IP = (unsigned long) uml_finishsetup;
658 (*switch_buf)[0].JB_SP = (unsigned long) stack +
659 UM_THREAD_SIZE - sizeof(void *);
660 break;
661 case INIT_JMP_CALLBACK:
662 (*cb_proc)(cb_arg);
663 longjmp(*cb_back, 1);
664 break;
665 case INIT_JMP_HALT:
666 kmalloc_ok = 0;
667 return 0;
668 case INIT_JMP_REBOOT:
669 kmalloc_ok = 0;
670 return 1;
671 default:
672 printk(UM_KERN_ERR "Bad sigsetjmp return in %s - %d\n",
673 __func__, n);
674 fatal_sigsegv();
675 }
676 longjmp(*switch_buf, 1);
677
678 /* unreachable */
679 printk(UM_KERN_ERR "impossible long jump!");
680 fatal_sigsegv();
681 return 0;
682 }
683
initial_thread_cb_skas(void (* proc)(void *),void * arg)684 void initial_thread_cb_skas(void (*proc)(void *), void *arg)
685 {
686 jmp_buf here;
687
688 cb_proc = proc;
689 cb_arg = arg;
690 cb_back = &here;
691
692 block_signals_trace();
693 if (UML_SETJMP(&here) == 0)
694 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK);
695 unblock_signals_trace();
696
697 cb_proc = NULL;
698 cb_arg = NULL;
699 cb_back = NULL;
700 }
701
halt_skas(void)702 void halt_skas(void)
703 {
704 block_signals_trace();
705 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT);
706 }
707
708 static bool noreboot;
709
noreboot_cmd_param(char * str,int * add)710 static int __init noreboot_cmd_param(char *str, int *add)
711 {
712 noreboot = true;
713 return 0;
714 }
715
716 __uml_setup("noreboot", noreboot_cmd_param,
717 "noreboot\n"
718 " Rather than rebooting, exit always, akin to QEMU's -no-reboot option.\n"
719 " This is useful if you're using CONFIG_PANIC_TIMEOUT in order to catch\n"
720 " crashes in CI\n");
721
reboot_skas(void)722 void reboot_skas(void)
723 {
724 block_signals_trace();
725 UML_LONGJMP(&initial_jmpbuf, noreboot ? INIT_JMP_HALT : INIT_JMP_REBOOT);
726 }
727
__switch_mm(struct mm_id * mm_idp)728 void __switch_mm(struct mm_id *mm_idp)
729 {
730 userspace_pid[0] = mm_idp->u.pid;
731 kill_userspace_mm[0] = mm_idp->kill;
732 }
733