1 /*
2 * Copyright (C) 2002- 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
4 */
5
6 #include <stdlib.h>
7 #include <unistd.h>
8 #include <sched.h>
9 #include <errno.h>
10 #include <string.h>
11 #include <sys/mman.h>
12 #include <sys/wait.h>
13 #include <asm/unistd.h>
14 #include <as-layout.h>
15 #include <init.h>
16 #include <kern_util.h>
17 #include <mem.h>
18 #include <os.h>
19 #include <proc_mm.h>
20 #include <ptrace_user.h>
21 #include <registers.h>
22 #include <skas.h>
23 #include <skas_ptrace.h>
24 #include <sysdep/stub.h>
25
is_skas_winch(int pid,int fd,void * data)26 int is_skas_winch(int pid, int fd, void *data)
27 {
28 return pid == getpgrp();
29 }
30
ptrace_dump_regs(int pid)31 static int ptrace_dump_regs(int pid)
32 {
33 unsigned long regs[MAX_REG_NR];
34 int i;
35
36 if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
37 return -errno;
38
39 printk(UM_KERN_ERR "Stub registers -\n");
40 for (i = 0; i < ARRAY_SIZE(regs); i++)
41 printk(UM_KERN_ERR "\t%d - %lx\n", i, regs[i]);
42
43 return 0;
44 }
45
46 /*
47 * Signals that are OK to receive in the stub - we'll just continue it.
48 * SIGWINCH will happen when UML is inside a detached screen.
49 */
50 #define STUB_SIG_MASK ((1 << SIGVTALRM) | (1 << SIGWINCH))
51
52 /* Signals that the stub will finish with - anything else is an error */
53 #define STUB_DONE_MASK (1 << SIGTRAP)
54
wait_stub_done(int pid)55 void wait_stub_done(int pid)
56 {
57 int n, status, err;
58
59 while (1) {
60 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
61 if ((n < 0) || !WIFSTOPPED(status))
62 goto bad_wait;
63
64 if (((1 << WSTOPSIG(status)) & STUB_SIG_MASK) == 0)
65 break;
66
67 err = ptrace(PTRACE_CONT, pid, 0, 0);
68 if (err) {
69 printk(UM_KERN_ERR "wait_stub_done : continue failed, "
70 "errno = %d\n", errno);
71 fatal_sigsegv();
72 }
73 }
74
75 if (((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0)
76 return;
77
78 bad_wait:
79 err = ptrace_dump_regs(pid);
80 if (err)
81 printk(UM_KERN_ERR "Failed to get registers from stub, "
82 "errno = %d\n", -err);
83 printk(UM_KERN_ERR "wait_stub_done : failed to wait for SIGTRAP, "
84 "pid = %d, n = %d, errno = %d, status = 0x%x\n", pid, n, errno,
85 status);
86 fatal_sigsegv();
87 }
88
89 extern unsigned long current_stub_stack(void);
90
get_skas_faultinfo(int pid,struct faultinfo * fi)91 static void get_skas_faultinfo(int pid, struct faultinfo *fi)
92 {
93 int err;
94
95 if (ptrace_faultinfo) {
96 err = ptrace(PTRACE_FAULTINFO, pid, 0, fi);
97 if (err) {
98 printk(UM_KERN_ERR "get_skas_faultinfo - "
99 "PTRACE_FAULTINFO failed, errno = %d\n", errno);
100 fatal_sigsegv();
101 }
102
103 /* Special handling for i386, which has different structs */
104 if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo))
105 memset((char *)fi + sizeof(struct ptrace_faultinfo), 0,
106 sizeof(struct faultinfo) -
107 sizeof(struct ptrace_faultinfo));
108 }
109 else {
110 unsigned long fpregs[FP_SIZE];
111
112 err = get_fp_registers(pid, fpregs);
113 if (err < 0) {
114 printk(UM_KERN_ERR "save_fp_registers returned %d\n",
115 err);
116 fatal_sigsegv();
117 }
118 err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV);
119 if (err) {
120 printk(UM_KERN_ERR "Failed to continue stub, pid = %d, "
121 "errno = %d\n", pid, errno);
122 fatal_sigsegv();
123 }
124 wait_stub_done(pid);
125
126 /*
127 * faultinfo is prepared by the stub-segv-handler at start of
128 * the stub stack page. We just have to copy it.
129 */
130 memcpy(fi, (void *)current_stub_stack(), sizeof(*fi));
131
132 err = put_fp_registers(pid, fpregs);
133 if (err < 0) {
134 printk(UM_KERN_ERR "put_fp_registers returned %d\n",
135 err);
136 fatal_sigsegv();
137 }
138 }
139 }
140
handle_segv(int pid,struct uml_pt_regs * regs)141 static void handle_segv(int pid, struct uml_pt_regs * regs)
142 {
143 get_skas_faultinfo(pid, ®s->faultinfo);
144 segv(regs->faultinfo, 0, 1, NULL);
145 }
146
147 /*
148 * To use the same value of using_sysemu as the caller, ask it that value
149 * (in local_using_sysemu
150 */
handle_trap(int pid,struct uml_pt_regs * regs,int local_using_sysemu)151 static void handle_trap(int pid, struct uml_pt_regs *regs,
152 int local_using_sysemu)
153 {
154 int err, status;
155
156 if ((UPT_IP(regs) >= STUB_START) && (UPT_IP(regs) < STUB_END))
157 fatal_sigsegv();
158
159 /* Mark this as a syscall */
160 UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->gp);
161
162 if (!local_using_sysemu)
163 {
164 err = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET,
165 __NR_getpid);
166 if (err < 0) {
167 printk(UM_KERN_ERR "handle_trap - nullifying syscall "
168 "failed, errno = %d\n", errno);
169 fatal_sigsegv();
170 }
171
172 err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
173 if (err < 0) {
174 printk(UM_KERN_ERR "handle_trap - continuing to end of "
175 "syscall failed, errno = %d\n", errno);
176 fatal_sigsegv();
177 }
178
179 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
180 if ((err < 0) || !WIFSTOPPED(status) ||
181 (WSTOPSIG(status) != SIGTRAP + 0x80)) {
182 err = ptrace_dump_regs(pid);
183 if (err)
184 printk(UM_KERN_ERR "Failed to get registers "
185 "from process, errno = %d\n", -err);
186 printk(UM_KERN_ERR "handle_trap - failed to wait at "
187 "end of syscall, errno = %d, status = %d\n",
188 errno, status);
189 fatal_sigsegv();
190 }
191 }
192
193 handle_syscall(regs);
194 }
195
196 extern int __syscall_stub_start;
197
userspace_tramp(void * stack)198 static int userspace_tramp(void *stack)
199 {
200 void *addr;
201 int err;
202
203 ptrace(PTRACE_TRACEME, 0, 0, 0);
204
205 signal(SIGTERM, SIG_DFL);
206 signal(SIGWINCH, SIG_IGN);
207 err = set_interval();
208 if (err) {
209 printk(UM_KERN_ERR "userspace_tramp - setting timer failed, "
210 "errno = %d\n", err);
211 exit(1);
212 }
213
214 if (!proc_mm) {
215 /*
216 * This has a pte, but it can't be mapped in with the usual
217 * tlb_flush mechanism because this is part of that mechanism
218 */
219 int fd;
220 unsigned long long offset;
221 fd = phys_mapping(to_phys(&__syscall_stub_start), &offset);
222 addr = mmap64((void *) STUB_CODE, UM_KERN_PAGE_SIZE,
223 PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
224 if (addr == MAP_FAILED) {
225 printk(UM_KERN_ERR "mapping mmap stub at 0x%lx failed, "
226 "errno = %d\n", STUB_CODE, errno);
227 exit(1);
228 }
229
230 if (stack != NULL) {
231 fd = phys_mapping(to_phys(stack), &offset);
232 addr = mmap((void *) STUB_DATA,
233 UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
234 MAP_FIXED | MAP_SHARED, fd, offset);
235 if (addr == MAP_FAILED) {
236 printk(UM_KERN_ERR "mapping segfault stack "
237 "at 0x%lx failed, errno = %d\n",
238 STUB_DATA, errno);
239 exit(1);
240 }
241 }
242 }
243 if (!ptrace_faultinfo && (stack != NULL)) {
244 struct sigaction sa;
245
246 unsigned long v = STUB_CODE +
247 (unsigned long) stub_segv_handler -
248 (unsigned long) &__syscall_stub_start;
249
250 set_sigstack((void *) STUB_DATA, UM_KERN_PAGE_SIZE);
251 sigemptyset(&sa.sa_mask);
252 sa.sa_flags = SA_ONSTACK | SA_NODEFER | SA_SIGINFO;
253 sa.sa_sigaction = (void *) v;
254 sa.sa_restorer = NULL;
255 if (sigaction(SIGSEGV, &sa, NULL) < 0) {
256 printk(UM_KERN_ERR "userspace_tramp - setting SIGSEGV "
257 "handler failed - errno = %d\n", errno);
258 exit(1);
259 }
260 }
261
262 kill(os_getpid(), SIGSTOP);
263 return 0;
264 }
265
266 /* Each element set once, and only accessed by a single processor anyway */
267 #undef NR_CPUS
268 #define NR_CPUS 1
269 int userspace_pid[NR_CPUS];
270
start_userspace(unsigned long stub_stack)271 int start_userspace(unsigned long stub_stack)
272 {
273 void *stack;
274 unsigned long sp;
275 int pid, status, n, flags, err;
276
277 stack = mmap(NULL, UM_KERN_PAGE_SIZE,
278 PROT_READ | PROT_WRITE | PROT_EXEC,
279 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
280 if (stack == MAP_FAILED) {
281 err = -errno;
282 printk(UM_KERN_ERR "start_userspace : mmap failed, "
283 "errno = %d\n", errno);
284 return err;
285 }
286
287 sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *);
288
289 flags = CLONE_FILES;
290 if (proc_mm)
291 flags |= CLONE_VM;
292 else
293 flags |= SIGCHLD;
294
295 pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
296 if (pid < 0) {
297 err = -errno;
298 printk(UM_KERN_ERR "start_userspace : clone failed, "
299 "errno = %d\n", errno);
300 return err;
301 }
302
303 do {
304 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
305 if (n < 0) {
306 err = -errno;
307 printk(UM_KERN_ERR "start_userspace : wait failed, "
308 "errno = %d\n", errno);
309 goto out_kill;
310 }
311 } while (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM));
312
313 if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) {
314 err = -EINVAL;
315 printk(UM_KERN_ERR "start_userspace : expected SIGSTOP, got "
316 "status = %d\n", status);
317 goto out_kill;
318 }
319
320 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
321 (void *) PTRACE_O_TRACESYSGOOD) < 0) {
322 err = -errno;
323 printk(UM_KERN_ERR "start_userspace : PTRACE_OLDSETOPTIONS "
324 "failed, errno = %d\n", errno);
325 goto out_kill;
326 }
327
328 if (munmap(stack, UM_KERN_PAGE_SIZE) < 0) {
329 err = -errno;
330 printk(UM_KERN_ERR "start_userspace : munmap failed, "
331 "errno = %d\n", errno);
332 goto out_kill;
333 }
334
335 return pid;
336
337 out_kill:
338 os_kill_ptraced_process(pid, 1);
339 return err;
340 }
341
userspace(struct uml_pt_regs * regs)342 void userspace(struct uml_pt_regs *regs)
343 {
344 struct itimerval timer;
345 unsigned long long nsecs, now;
346 int err, status, op, pid = userspace_pid[0];
347 /* To prevent races if using_sysemu changes under us.*/
348 int local_using_sysemu;
349 siginfo_t si;
350
351 /* Handle any immediate reschedules or signals */
352 interrupt_end();
353
354 if (getitimer(ITIMER_VIRTUAL, &timer))
355 printk(UM_KERN_ERR "Failed to get itimer, errno = %d\n", errno);
356 nsecs = timer.it_value.tv_sec * UM_NSEC_PER_SEC +
357 timer.it_value.tv_usec * UM_NSEC_PER_USEC;
358 nsecs += os_nsecs();
359
360 while (1) {
361 /*
362 * This can legitimately fail if the process loads a
363 * bogus value into a segment register. It will
364 * segfault and PTRACE_GETREGS will read that value
365 * out of the process. However, PTRACE_SETREGS will
366 * fail. In this case, there is nothing to do but
367 * just kill the process.
368 */
369 if (ptrace(PTRACE_SETREGS, pid, 0, regs->gp))
370 fatal_sigsegv();
371
372 if (put_fp_registers(pid, regs->fp))
373 fatal_sigsegv();
374
375 /* Now we set local_using_sysemu to be used for one loop */
376 local_using_sysemu = get_using_sysemu();
377
378 op = SELECT_PTRACE_OPERATION(local_using_sysemu,
379 singlestepping(NULL));
380
381 if (ptrace(op, pid, 0, 0)) {
382 printk(UM_KERN_ERR "userspace - ptrace continue "
383 "failed, op = %d, errno = %d\n", op, errno);
384 fatal_sigsegv();
385 }
386
387 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
388 if (err < 0) {
389 printk(UM_KERN_ERR "userspace - wait failed, "
390 "errno = %d\n", errno);
391 fatal_sigsegv();
392 }
393
394 regs->is_user = 1;
395 if (ptrace(PTRACE_GETREGS, pid, 0, regs->gp)) {
396 printk(UM_KERN_ERR "userspace - PTRACE_GETREGS failed, "
397 "errno = %d\n", errno);
398 fatal_sigsegv();
399 }
400
401 if (get_fp_registers(pid, regs->fp)) {
402 printk(UM_KERN_ERR "userspace - get_fp_registers failed, "
403 "errno = %d\n", errno);
404 fatal_sigsegv();
405 }
406
407 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
408
409 if (WIFSTOPPED(status)) {
410 int sig = WSTOPSIG(status);
411
412 ptrace(PTRACE_GETSIGINFO, pid, 0, (struct siginfo *)&si);
413
414 switch (sig) {
415 case SIGSEGV:
416 if (PTRACE_FULL_FAULTINFO ||
417 !ptrace_faultinfo) {
418 get_skas_faultinfo(pid,
419 ®s->faultinfo);
420 (*sig_info[SIGSEGV])(SIGSEGV, (struct siginfo *)&si,
421 regs);
422 }
423 else handle_segv(pid, regs);
424 break;
425 case SIGTRAP + 0x80:
426 handle_trap(pid, regs, local_using_sysemu);
427 break;
428 case SIGTRAP:
429 relay_signal(SIGTRAP, (struct siginfo *)&si, regs);
430 break;
431 case SIGVTALRM:
432 now = os_nsecs();
433 if (now < nsecs)
434 break;
435 block_signals();
436 (*sig_info[sig])(sig, (struct siginfo *)&si, regs);
437 unblock_signals();
438 nsecs = timer.it_value.tv_sec *
439 UM_NSEC_PER_SEC +
440 timer.it_value.tv_usec *
441 UM_NSEC_PER_USEC;
442 nsecs += os_nsecs();
443 break;
444 case SIGIO:
445 case SIGILL:
446 case SIGBUS:
447 case SIGFPE:
448 case SIGWINCH:
449 block_signals();
450 (*sig_info[sig])(sig, (struct siginfo *)&si, regs);
451 unblock_signals();
452 break;
453 default:
454 printk(UM_KERN_ERR "userspace - child stopped "
455 "with signal %d\n", sig);
456 fatal_sigsegv();
457 }
458 pid = userspace_pid[0];
459 interrupt_end();
460
461 /* Avoid -ERESTARTSYS handling in host */
462 if (PT_SYSCALL_NR_OFFSET != PT_SYSCALL_RET_OFFSET)
463 PT_SYSCALL_NR(regs->gp) = -1;
464 }
465 }
466 }
467
468 static unsigned long thread_regs[MAX_REG_NR];
469 static unsigned long thread_fp_regs[FP_SIZE];
470
init_thread_regs(void)471 static int __init init_thread_regs(void)
472 {
473 get_safe_registers(thread_regs, thread_fp_regs);
474 /* Set parent's instruction pointer to start of clone-stub */
475 thread_regs[REGS_IP_INDEX] = STUB_CODE +
476 (unsigned long) stub_clone_handler -
477 (unsigned long) &__syscall_stub_start;
478 thread_regs[REGS_SP_INDEX] = STUB_DATA + UM_KERN_PAGE_SIZE -
479 sizeof(void *);
480 #ifdef __SIGNAL_FRAMESIZE
481 thread_regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
482 #endif
483 return 0;
484 }
485
486 __initcall(init_thread_regs);
487
copy_context_skas0(unsigned long new_stack,int pid)488 int copy_context_skas0(unsigned long new_stack, int pid)
489 {
490 struct timeval tv = { .tv_sec = 0, .tv_usec = UM_USEC_PER_SEC / UM_HZ };
491 int err;
492 unsigned long current_stack = current_stub_stack();
493 struct stub_data *data = (struct stub_data *) current_stack;
494 struct stub_data *child_data = (struct stub_data *) new_stack;
495 unsigned long long new_offset;
496 int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset);
497
498 /*
499 * prepare offset and fd of child's stack as argument for parent's
500 * and child's mmap2 calls
501 */
502 *data = ((struct stub_data) { .offset = MMAP_OFFSET(new_offset),
503 .fd = new_fd,
504 .timer = ((struct itimerval)
505 { .it_value = tv,
506 .it_interval = tv }) });
507
508 err = ptrace_setregs(pid, thread_regs);
509 if (err < 0) {
510 err = -errno;
511 printk(UM_KERN_ERR "copy_context_skas0 : PTRACE_SETREGS "
512 "failed, pid = %d, errno = %d\n", pid, -err);
513 return err;
514 }
515
516 err = put_fp_registers(pid, thread_fp_regs);
517 if (err < 0) {
518 printk(UM_KERN_ERR "copy_context_skas0 : put_fp_registers "
519 "failed, pid = %d, err = %d\n", pid, err);
520 return err;
521 }
522
523 /* set a well known return code for detection of child write failure */
524 child_data->err = 12345678;
525
526 /*
527 * Wait, until parent has finished its work: read child's pid from
528 * parent's stack, and check, if bad result.
529 */
530 err = ptrace(PTRACE_CONT, pid, 0, 0);
531 if (err) {
532 err = -errno;
533 printk(UM_KERN_ERR "Failed to continue new process, pid = %d, "
534 "errno = %d\n", pid, errno);
535 return err;
536 }
537
538 wait_stub_done(pid);
539
540 pid = data->err;
541 if (pid < 0) {
542 printk(UM_KERN_ERR "copy_context_skas0 - stub-parent reports "
543 "error %d\n", -pid);
544 return pid;
545 }
546
547 /*
548 * Wait, until child has finished too: read child's result from
549 * child's stack and check it.
550 */
551 wait_stub_done(pid);
552 if (child_data->err != STUB_DATA) {
553 printk(UM_KERN_ERR "copy_context_skas0 - stub-child reports "
554 "error %ld\n", child_data->err);
555 err = child_data->err;
556 goto out_kill;
557 }
558
559 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
560 (void *)PTRACE_O_TRACESYSGOOD) < 0) {
561 err = -errno;
562 printk(UM_KERN_ERR "copy_context_skas0 : PTRACE_OLDSETOPTIONS "
563 "failed, errno = %d\n", errno);
564 goto out_kill;
565 }
566
567 return pid;
568
569 out_kill:
570 os_kill_ptraced_process(pid, 1);
571 return err;
572 }
573
574 /*
575 * This is used only, if stub pages are needed, while proc_mm is
576 * available. Opening /proc/mm creates a new mm_context, which lacks
577 * the stub-pages. Thus, we map them using /proc/mm-fd
578 */
map_stub_pages(int fd,unsigned long code,unsigned long data,unsigned long stack)579 int map_stub_pages(int fd, unsigned long code, unsigned long data,
580 unsigned long stack)
581 {
582 struct proc_mm_op mmop;
583 int n;
584 unsigned long long code_offset;
585 int code_fd = phys_mapping(to_phys((void *) &__syscall_stub_start),
586 &code_offset);
587
588 mmop = ((struct proc_mm_op) { .op = MM_MMAP,
589 .u =
590 { .mmap =
591 { .addr = code,
592 .len = UM_KERN_PAGE_SIZE,
593 .prot = PROT_EXEC,
594 .flags = MAP_FIXED | MAP_PRIVATE,
595 .fd = code_fd,
596 .offset = code_offset
597 } } });
598 CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop)));
599 if (n != sizeof(mmop)) {
600 n = errno;
601 printk(UM_KERN_ERR "mmap args - addr = 0x%lx, fd = %d, "
602 "offset = %llx\n", code, code_fd,
603 (unsigned long long) code_offset);
604 printk(UM_KERN_ERR "map_stub_pages : /proc/mm map for code "
605 "failed, err = %d\n", n);
606 return -n;
607 }
608
609 if (stack) {
610 unsigned long long map_offset;
611 int map_fd = phys_mapping(to_phys((void *)stack), &map_offset);
612 mmop = ((struct proc_mm_op)
613 { .op = MM_MMAP,
614 .u =
615 { .mmap =
616 { .addr = data,
617 .len = UM_KERN_PAGE_SIZE,
618 .prot = PROT_READ | PROT_WRITE,
619 .flags = MAP_FIXED | MAP_SHARED,
620 .fd = map_fd,
621 .offset = map_offset
622 } } });
623 CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop)));
624 if (n != sizeof(mmop)) {
625 n = errno;
626 printk(UM_KERN_ERR "map_stub_pages : /proc/mm map for "
627 "data failed, err = %d\n", n);
628 return -n;
629 }
630 }
631
632 return 0;
633 }
634
new_thread(void * stack,jmp_buf * buf,void (* handler)(void))635 void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
636 {
637 (*buf)[0].JB_IP = (unsigned long) handler;
638 (*buf)[0].JB_SP = (unsigned long) stack + UM_THREAD_SIZE -
639 sizeof(void *);
640 }
641
642 #define INIT_JMP_NEW_THREAD 0
643 #define INIT_JMP_CALLBACK 1
644 #define INIT_JMP_HALT 2
645 #define INIT_JMP_REBOOT 3
646
switch_threads(jmp_buf * me,jmp_buf * you)647 void switch_threads(jmp_buf *me, jmp_buf *you)
648 {
649 if (UML_SETJMP(me) == 0)
650 UML_LONGJMP(you, 1);
651 }
652
653 static jmp_buf initial_jmpbuf;
654
655 /* XXX Make these percpu */
656 static void (*cb_proc)(void *arg);
657 static void *cb_arg;
658 static jmp_buf *cb_back;
659
start_idle_thread(void * stack,jmp_buf * switch_buf)660 int start_idle_thread(void *stack, jmp_buf *switch_buf)
661 {
662 int n;
663
664 set_handler(SIGWINCH);
665
666 /*
667 * Can't use UML_SETJMP or UML_LONGJMP here because they save
668 * and restore signals, with the possible side-effect of
669 * trying to handle any signals which came when they were
670 * blocked, which can't be done on this stack.
671 * Signals must be blocked when jumping back here and restored
672 * after returning to the jumper.
673 */
674 n = setjmp(initial_jmpbuf);
675 switch (n) {
676 case INIT_JMP_NEW_THREAD:
677 (*switch_buf)[0].JB_IP = (unsigned long) new_thread_handler;
678 (*switch_buf)[0].JB_SP = (unsigned long) stack +
679 UM_THREAD_SIZE - sizeof(void *);
680 break;
681 case INIT_JMP_CALLBACK:
682 (*cb_proc)(cb_arg);
683 longjmp(*cb_back, 1);
684 break;
685 case INIT_JMP_HALT:
686 kmalloc_ok = 0;
687 return 0;
688 case INIT_JMP_REBOOT:
689 kmalloc_ok = 0;
690 return 1;
691 default:
692 printk(UM_KERN_ERR "Bad sigsetjmp return in "
693 "start_idle_thread - %d\n", n);
694 fatal_sigsegv();
695 }
696 longjmp(*switch_buf, 1);
697 }
698
initial_thread_cb_skas(void (* proc)(void *),void * arg)699 void initial_thread_cb_skas(void (*proc)(void *), void *arg)
700 {
701 jmp_buf here;
702
703 cb_proc = proc;
704 cb_arg = arg;
705 cb_back = &here;
706
707 block_signals();
708 if (UML_SETJMP(&here) == 0)
709 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK);
710 unblock_signals();
711
712 cb_proc = NULL;
713 cb_arg = NULL;
714 cb_back = NULL;
715 }
716
halt_skas(void)717 void halt_skas(void)
718 {
719 block_signals();
720 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT);
721 }
722
reboot_skas(void)723 void reboot_skas(void)
724 {
725 block_signals();
726 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_REBOOT);
727 }
728
__switch_mm(struct mm_id * mm_idp)729 void __switch_mm(struct mm_id *mm_idp)
730 {
731 int err;
732
733 /* FIXME: need cpu pid in __switch_mm */
734 if (proc_mm) {
735 err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0,
736 mm_idp->u.mm_fd);
737 if (err) {
738 printk(UM_KERN_ERR "__switch_mm - PTRACE_SWITCH_MM "
739 "failed, errno = %d\n", errno);
740 fatal_sigsegv();
741 }
742 }
743 else userspace_pid[0] = mm_idp->u.pid;
744 }
745