Line data Source code
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 :
26 0 : int is_skas_winch(int pid, int fd, void *data)
27 : {
28 0 : return pid == getpgrp();
29 : }
30 :
31 : static 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 :
79 0 : static int ptrace_dump_regs(int pid)
80 : {
81 : unsigned long regs[MAX_REG_NR];
82 : int i;
83 :
84 0 : if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
85 0 : return -errno;
86 :
87 0 : printk(UM_KERN_ERR "Stub registers -\n");
88 0 : for (i = 0; i < ARRAY_SIZE(regs); i++) {
89 0 : const char *regname = ptrace_reg_name(i);
90 :
91 0 : 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 :
106 0 : void wait_stub_done(int pid)
107 : {
108 : int n, status, err;
109 :
110 : while (1) {
111 0 : CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
112 0 : if ((n < 0) || !WIFSTOPPED(status))
113 : goto bad_wait;
114 :
115 0 : if (((1 << WSTOPSIG(status)) & STUB_SIG_MASK) == 0)
116 : break;
117 :
118 0 : err = ptrace(PTRACE_CONT, pid, 0, 0);
119 0 : if (err) {
120 0 : printk(UM_KERN_ERR "wait_stub_done : continue failed, "
121 : "errno = %d\n", errno);
122 0 : fatal_sigsegv();
123 : }
124 : }
125 :
126 0 : if (((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0)
127 0 : return;
128 :
129 : bad_wait:
130 0 : err = ptrace_dump_regs(pid);
131 0 : if (err)
132 0 : printk(UM_KERN_ERR "Failed to get registers from stub, "
133 : "errno = %d\n", -err);
134 0 : 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 0 : fatal_sigsegv();
138 : }
139 :
140 : extern unsigned long current_stub_stack(void);
141 :
142 0 : static void get_skas_faultinfo(int pid, struct faultinfo *fi, unsigned long *aux_fp_regs)
143 : {
144 : int err;
145 :
146 0 : err = get_fp_registers(pid, aux_fp_regs);
147 0 : if (err < 0) {
148 0 : printk(UM_KERN_ERR "save_fp_registers returned %d\n",
149 : err);
150 0 : fatal_sigsegv();
151 : }
152 0 : err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV);
153 0 : if (err) {
154 0 : printk(UM_KERN_ERR "Failed to continue stub, pid = %d, "
155 : "errno = %d\n", pid, errno);
156 0 : fatal_sigsegv();
157 : }
158 0 : 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 0 : memcpy(fi, (void *)current_stub_stack(), sizeof(*fi));
165 :
166 0 : err = put_fp_registers(pid, aux_fp_regs);
167 0 : if (err < 0) {
168 0 : printk(UM_KERN_ERR "put_fp_registers returned %d\n",
169 : err);
170 0 : fatal_sigsegv();
171 : }
172 0 : }
173 :
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 : */
184 0 : static void handle_trap(int pid, struct uml_pt_regs *regs,
185 : int local_using_sysemu)
186 : {
187 : int err, status;
188 :
189 0 : if ((UPT_IP(regs) >= STUB_START) && (UPT_IP(regs) < STUB_END))
190 0 : fatal_sigsegv();
191 :
192 0 : if (!local_using_sysemu)
193 : {
194 0 : err = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET,
195 : __NR_getpid);
196 0 : if (err < 0) {
197 0 : printk(UM_KERN_ERR "handle_trap - nullifying syscall "
198 : "failed, errno = %d\n", errno);
199 0 : fatal_sigsegv();
200 : }
201 :
202 0 : err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
203 0 : if (err < 0) {
204 0 : printk(UM_KERN_ERR "handle_trap - continuing to end of "
205 : "syscall failed, errno = %d\n", errno);
206 0 : fatal_sigsegv();
207 : }
208 :
209 0 : CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
210 0 : if ((err < 0) || !WIFSTOPPED(status) ||
211 0 : (WSTOPSIG(status) != SIGTRAP + 0x80)) {
212 0 : err = ptrace_dump_regs(pid);
213 0 : if (err)
214 0 : printk(UM_KERN_ERR "Failed to get registers "
215 : "from process, errno = %d\n", -err);
216 0 : printk(UM_KERN_ERR "handle_trap - failed to wait at "
217 : "end of syscall, errno = %d, status = %d\n",
218 : errno, status);
219 0 : fatal_sigsegv();
220 : }
221 : }
222 :
223 0 : handle_syscall(regs);
224 0 : }
225 :
226 : extern 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 : */
243 0 : static int userspace_tramp(void *stack)
244 : {
245 : void *addr;
246 : int fd;
247 : unsigned long long offset;
248 :
249 0 : ptrace(PTRACE_TRACEME, 0, 0, 0);
250 :
251 0 : signal(SIGTERM, SIG_DFL);
252 0 : signal(SIGWINCH, SIG_IGN);
253 :
254 0 : fd = phys_mapping(to_phys(__syscall_stub_start), &offset);
255 0 : addr = mmap64((void *) STUB_CODE, UM_KERN_PAGE_SIZE,
256 : PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
257 0 : if (addr == MAP_FAILED) {
258 0 : printk(UM_KERN_ERR "mapping mmap stub at 0x%lx failed, "
259 : "errno = %d\n", STUB_CODE, errno);
260 0 : exit(1);
261 : }
262 :
263 0 : if (stack != NULL) {
264 0 : fd = phys_mapping(to_phys(stack), &offset);
265 0 : addr = mmap((void *) STUB_DATA,
266 : UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
267 : MAP_FIXED | MAP_SHARED, fd, offset);
268 0 : if (addr == MAP_FAILED) {
269 0 : printk(UM_KERN_ERR "mapping segfault stack "
270 : "at 0x%lx failed, errno = %d\n",
271 : STUB_DATA, errno);
272 0 : exit(1);
273 : }
274 : }
275 0 : if (stack != NULL) {
276 : struct sigaction sa;
277 :
278 0 : unsigned long v = STUB_CODE +
279 0 : (unsigned long) stub_segv_handler -
280 : (unsigned long) __syscall_stub_start;
281 :
282 0 : set_sigstack((void *) STUB_DATA, UM_KERN_PAGE_SIZE);
283 0 : sigemptyset(&sa.sa_mask);
284 0 : sa.sa_flags = SA_ONSTACK | SA_NODEFER | SA_SIGINFO;
285 0 : sa.sa_sigaction = (void *) v;
286 0 : sa.sa_restorer = NULL;
287 0 : if (sigaction(SIGSEGV, &sa, NULL) < 0) {
288 0 : printk(UM_KERN_ERR "userspace_tramp - setting SIGSEGV "
289 : "handler failed - errno = %d\n", errno);
290 0 : exit(1);
291 : }
292 : }
293 :
294 0 : kill(os_getpid(), SIGSTOP);
295 0 : return 0;
296 : }
297 :
298 : int userspace_pid[NR_CPUS];
299 : int 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 : */
312 0 : int 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 0 : stack = mmap(NULL, UM_KERN_PAGE_SIZE,
320 : PROT_READ | PROT_WRITE | PROT_EXEC,
321 : MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
322 0 : if (stack == MAP_FAILED) {
323 0 : err = -errno;
324 0 : printk(UM_KERN_ERR "start_userspace : mmap failed, "
325 : "errno = %d\n", errno);
326 0 : return err;
327 : }
328 :
329 : /* set stack pointer to the end of the stack page, so it can grow downwards */
330 0 : sp = (unsigned long)stack + UM_KERN_PAGE_SIZE;
331 :
332 0 : flags = CLONE_FILES | SIGCHLD;
333 :
334 : /* clone into new userspace process */
335 0 : pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
336 0 : if (pid < 0) {
337 0 : err = -errno;
338 0 : printk(UM_KERN_ERR "start_userspace : clone failed, "
339 : "errno = %d\n", errno);
340 0 : return err;
341 : }
342 :
343 : do {
344 0 : CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
345 0 : if (n < 0) {
346 0 : err = -errno;
347 0 : printk(UM_KERN_ERR "start_userspace : wait failed, "
348 : "errno = %d\n", errno);
349 0 : goto out_kill;
350 : }
351 0 : } while (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGALRM));
352 :
353 0 : if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) {
354 0 : err = -EINVAL;
355 0 : printk(UM_KERN_ERR "start_userspace : expected SIGSTOP, got "
356 : "status = %d\n", status);
357 0 : goto out_kill;
358 : }
359 :
360 0 : if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
361 : (void *) PTRACE_O_TRACESYSGOOD) < 0) {
362 0 : err = -errno;
363 0 : printk(UM_KERN_ERR "start_userspace : PTRACE_OLDSETOPTIONS "
364 : "failed, errno = %d\n", errno);
365 0 : goto out_kill;
366 : }
367 :
368 0 : if (munmap(stack, UM_KERN_PAGE_SIZE) < 0) {
369 0 : err = -errno;
370 0 : printk(UM_KERN_ERR "start_userspace : munmap failed, "
371 : "errno = %d\n", errno);
372 0 : goto out_kill;
373 : }
374 :
375 : return pid;
376 :
377 : out_kill:
378 0 : os_kill_ptraced_process(pid, 1);
379 0 : return err;
380 : }
381 :
382 0 : void userspace(struct uml_pt_regs *regs, unsigned long *aux_fp_regs)
383 : {
384 0 : 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 0 : interrupt_end();
391 :
392 : while (1) {
393 0 : if (kill_userspace_mm[0])
394 0 : 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 0 : if (ptrace(PTRACE_SETREGS, pid, 0, regs->gp)) {
405 0 : printk(UM_KERN_ERR "userspace - ptrace set regs "
406 : "failed, errno = %d\n", errno);
407 0 : fatal_sigsegv();
408 : }
409 :
410 0 : if (put_fp_registers(pid, regs->fp)) {
411 0 : printk(UM_KERN_ERR "userspace - ptrace set fp regs "
412 : "failed, errno = %d\n", errno);
413 0 : fatal_sigsegv();
414 : }
415 :
416 : /* Now we set local_using_sysemu to be used for one loop */
417 0 : local_using_sysemu = get_using_sysemu();
418 :
419 0 : op = SELECT_PTRACE_OPERATION(local_using_sysemu,
420 : singlestepping(NULL));
421 :
422 0 : if (ptrace(op, pid, 0, 0)) {
423 0 : printk(UM_KERN_ERR "userspace - ptrace continue "
424 : "failed, op = %d, errno = %d\n", op, errno);
425 0 : fatal_sigsegv();
426 : }
427 :
428 0 : CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
429 0 : if (err < 0) {
430 0 : printk(UM_KERN_ERR "userspace - wait failed, "
431 : "errno = %d\n", errno);
432 0 : fatal_sigsegv();
433 : }
434 :
435 0 : regs->is_user = 1;
436 0 : if (ptrace(PTRACE_GETREGS, pid, 0, regs->gp)) {
437 0 : printk(UM_KERN_ERR "userspace - PTRACE_GETREGS failed, "
438 : "errno = %d\n", errno);
439 0 : fatal_sigsegv();
440 : }
441 :
442 0 : if (get_fp_registers(pid, regs->fp)) {
443 0 : printk(UM_KERN_ERR "userspace - get_fp_registers failed, "
444 : "errno = %d\n", errno);
445 0 : fatal_sigsegv();
446 : }
447 :
448 0 : UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
449 :
450 0 : if (WIFSTOPPED(status)) {
451 0 : 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 0 : ptrace(PTRACE_GETSIGINFO, pid, 0, (struct siginfo *)&si);
465 0 : break;
466 : }
467 :
468 0 : switch (sig) {
469 : case SIGSEGV:
470 : if (PTRACE_FULL_FAULTINFO) {
471 0 : get_skas_faultinfo(pid,
472 : ®s->faultinfo, aux_fp_regs);
473 0 : (*sig_info[SIGSEGV])(SIGSEGV, (struct siginfo *)&si,
474 : regs);
475 : }
476 : else handle_segv(pid, regs, aux_fp_regs);
477 0 : break;
478 : case SIGTRAP + 0x80:
479 0 : handle_trap(pid, regs, local_using_sysemu);
480 0 : break;
481 : case SIGTRAP:
482 0 : relay_signal(SIGTRAP, (struct siginfo *)&si, regs);
483 0 : break;
484 : case SIGALRM:
485 : break;
486 : case SIGIO:
487 : case SIGILL:
488 : case SIGBUS:
489 : case SIGFPE:
490 : case SIGWINCH:
491 0 : block_signals_trace();
492 0 : (*sig_info[sig])(sig, (struct siginfo *)&si, regs);
493 0 : unblock_signals_trace();
494 0 : break;
495 : default:
496 0 : printk(UM_KERN_ERR "userspace - child stopped "
497 : "with signal %d\n", sig);
498 0 : fatal_sigsegv();
499 : }
500 0 : pid = userspace_pid[0];
501 0 : interrupt_end();
502 :
503 : /* Avoid -ERESTARTSYS handling in host */
504 : if (PT_SYSCALL_NR_OFFSET != PT_SYSCALL_RET_OFFSET)
505 0 : PT_SYSCALL_NR(regs->gp) = -1;
506 : }
507 : }
508 : }
509 :
510 : static unsigned long thread_regs[MAX_REG_NR];
511 : static unsigned long thread_fp_regs[FP_SIZE];
512 :
513 1 : static int __init init_thread_regs(void)
514 : {
515 1 : get_safe_registers(thread_regs, thread_fp_regs);
516 : /* Set parent's instruction pointer to start of clone-stub */
517 1 : thread_regs[REGS_IP_INDEX] = STUB_CODE +
518 1 : (unsigned long) stub_clone_handler -
519 : (unsigned long) __syscall_stub_start;
520 1 : 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 1 : return 0;
526 : }
527 :
528 : __initcall(init_thread_regs);
529 :
530 0 : int copy_context_skas0(unsigned long new_stack, int pid)
531 : {
532 : int err;
533 0 : unsigned long current_stack = current_stub_stack();
534 0 : struct stub_data *data = (struct stub_data *) current_stack;
535 0 : struct stub_data *child_data = (struct stub_data *) new_stack;
536 : unsigned long long new_offset;
537 0 : 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 0 : *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 0 : *child_data = ((struct stub_data) {
551 : .child_err = -ESRCH,
552 : });
553 :
554 0 : err = ptrace_setregs(pid, thread_regs);
555 0 : if (err < 0) {
556 0 : err = -errno;
557 0 : printk(UM_KERN_ERR "copy_context_skas0 : PTRACE_SETREGS "
558 : "failed, pid = %d, errno = %d\n", pid, -err);
559 0 : return err;
560 : }
561 :
562 0 : err = put_fp_registers(pid, thread_fp_regs);
563 0 : if (err < 0) {
564 0 : printk(UM_KERN_ERR "copy_context_skas0 : put_fp_registers "
565 : "failed, pid = %d, err = %d\n", pid, err);
566 0 : 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 0 : err = ptrace(PTRACE_CONT, pid, 0, 0);
574 0 : if (err) {
575 0 : err = -errno;
576 0 : printk(UM_KERN_ERR "Failed to continue new process, pid = %d, "
577 : "errno = %d\n", pid, errno);
578 0 : return err;
579 : }
580 :
581 0 : wait_stub_done(pid);
582 :
583 0 : pid = data->parent_err;
584 0 : if (pid < 0) {
585 0 : printk(UM_KERN_ERR "copy_context_skas0 - stub-parent reports "
586 : "error %d\n", -pid);
587 0 : 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 0 : wait_stub_done(pid);
595 0 : if (child_data->child_err != STUB_DATA) {
596 0 : printk(UM_KERN_ERR "copy_context_skas0 - stub-child %d reports "
597 : "error %ld\n", pid, data->child_err);
598 0 : err = data->child_err;
599 0 : goto out_kill;
600 : }
601 :
602 0 : if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
603 : (void *)PTRACE_O_TRACESYSGOOD) < 0) {
604 0 : err = -errno;
605 0 : printk(UM_KERN_ERR "copy_context_skas0 : PTRACE_OLDSETOPTIONS "
606 : "failed, errno = %d\n", errno);
607 0 : goto out_kill;
608 : }
609 :
610 : return pid;
611 :
612 : out_kill:
613 0 : os_kill_ptraced_process(pid, 1);
614 0 : return err;
615 : }
616 :
617 107 : void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
618 : {
619 107 : (*buf)[0].JB_IP = (unsigned long) handler;
620 107 : (*buf)[0].JB_SP = (unsigned long) stack + UM_THREAD_SIZE -
621 : sizeof(void *);
622 107 : }
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 :
629 618 : void switch_threads(jmp_buf *me, jmp_buf *you)
630 : {
631 618 : if (UML_SETJMP(me) == 0)
632 618 : UML_LONGJMP(you, 1);
633 511 : }
634 :
635 : static jmp_buf initial_jmpbuf;
636 :
637 : /* XXX Make these percpu */
638 : static void (*cb_proc)(void *arg);
639 : static void *cb_arg;
640 : static jmp_buf *cb_back;
641 :
642 1 : int start_idle_thread(void *stack, jmp_buf *switch_buf)
643 : {
644 : int n;
645 :
646 1 : 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 1 : n = setjmp(initial_jmpbuf);
657 3 : switch (n) {
658 : case INIT_JMP_NEW_THREAD:
659 1 : (*switch_buf)[0].JB_IP = (unsigned long) uml_finishsetup;
660 2 : (*switch_buf)[0].JB_SP = (unsigned long) stack +
661 1 : UM_THREAD_SIZE - sizeof(void *);
662 1 : break;
663 : case INIT_JMP_CALLBACK:
664 1 : (*cb_proc)(cb_arg);
665 1 : longjmp(*cb_back, 1);
666 0 : break;
667 : case INIT_JMP_HALT:
668 1 : kmalloc_ok = 0;
669 1 : return 0;
670 : case INIT_JMP_REBOOT:
671 0 : kmalloc_ok = 0;
672 0 : return 1;
673 : default:
674 0 : printk(UM_KERN_ERR "Bad sigsetjmp return in "
675 : "start_idle_thread - %d\n", n);
676 0 : fatal_sigsegv();
677 : }
678 1 : longjmp(*switch_buf, 1);
679 :
680 : /* unreachable */
681 0 : printk(UM_KERN_ERR "impossible long jump!");
682 0 : fatal_sigsegv();
683 : return 0;
684 : }
685 :
686 1 : void initial_thread_cb_skas(void (*proc)(void *), void *arg)
687 : {
688 : jmp_buf here;
689 :
690 1 : cb_proc = proc;
691 1 : cb_arg = arg;
692 1 : cb_back = &here;
693 :
694 1 : block_signals_trace();
695 1 : if (UML_SETJMP(&here) == 0)
696 1 : UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK);
697 1 : unblock_signals_trace();
698 :
699 1 : cb_proc = NULL;
700 1 : cb_arg = NULL;
701 1 : cb_back = NULL;
702 1 : }
703 :
704 1 : void halt_skas(void)
705 : {
706 1 : block_signals_trace();
707 1 : UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT);
708 0 : }
709 :
710 0 : void reboot_skas(void)
711 : {
712 0 : block_signals_trace();
713 0 : UML_LONGJMP(&initial_jmpbuf, INIT_JMP_REBOOT);
714 0 : }
715 :
716 0 : void __switch_mm(struct mm_id *mm_idp)
717 : {
718 0 : userspace_pid[0] = mm_idp->u.pid;
719 0 : kill_userspace_mm[0] = mm_idp->kill;
720 0 : }
|
