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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
99
100
101#define STUB_SIG_MASK ((1 << SIGALRM) | (1 << SIGWINCH))
102
103
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
162
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
182
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
230
231
232
233
234
235
236
237
238
239
240
241
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
303
304
305
306
307
308
309
310
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
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
330 sp = (unsigned long)stack + UM_KERN_PAGE_SIZE;
331
332 flags = CLONE_FILES | SIGCHLD;
333
334
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
386 int local_using_sysemu;
387 siginfo_t si;
388
389
390 interrupt_end();
391
392 while (1) {
393 if (kill_userspace_mm[0])
394 fatal_sigsegv();
395
396
397
398
399
400
401
402
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
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;
449
450 if (WIFSTOPPED(status)) {
451 int sig = WSTOPSIG(status);
452
453
454
455
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
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
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
541
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
571
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
592
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
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
650
651
652
653
654
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
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}
721