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V4L/DVB (6926): tda18271: consolidate table lookup functions
[linux-2.6/verdex.git] / arch / um / os-Linux / skas / process.c
blobe8b7a97e83d3eb8d75785b6a44e29492ae81efcf
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/ptrace.h>
13 #include <sys/wait.h>
14 #include <asm/unistd.h>
15 #include "as-layout.h"
16 #include "chan_user.h"
17 #include "kern_constants.h"
18 #include "mem.h"
19 #include "os.h"
20 #include "process.h"
21 #include "proc_mm.h"
22 #include "ptrace_user.h"
23 #include "registers.h"
24 #include "skas.h"
25 #include "skas_ptrace.h"
26 #include "user.h"
27 #include "sysdep/stub.h"
28
29 int is_skas_winch(int pid, int fd, void *data)
30 {
31 if (pid != getpgrp())
32 return 0;
33
34 register_winch_irq(-1, fd, -1, data, 0);
35 return 1;
36 }
37
38 static int ptrace_dump_regs(int pid)
39 {
40 unsigned long regs[MAX_REG_NR];
41 int i;
42
43 if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
44 return -errno;
45
46 printk(UM_KERN_ERR "Stub registers -\n");
47 for (i = 0; i < ARRAY_SIZE(regs); i++)
48 printk(UM_KERN_ERR "\t%d - %lx\n", i, regs[i]);
49
50 return 0;
51 }
52
53 /*
54 * Signals that are OK to receive in the stub - we'll just continue it.
55 * SIGWINCH will happen when UML is inside a detached screen.
56 */
57 #define STUB_SIG_MASK ((1 << SIGVTALRM) | (1 << SIGWINCH))
58
59 /* Signals that the stub will finish with - anything else is an error */
60 #define STUB_DONE_MASK ((1 << SIGUSR1) | (1 << SIGTRAP))
61
62 void wait_stub_done(int pid)
63 {
64 int n, status, err;
65
66 while (1) {
67 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
68 if ((n < 0) || !WIFSTOPPED(status))
69 goto bad_wait;
70
71 if (((1 << WSTOPSIG(status)) & STUB_SIG_MASK) == 0)
72 break;
73
74 err = ptrace(PTRACE_CONT, pid, 0, 0);
75 if (err)
76 panic("wait_stub_done : continue failed, errno = %d\n",
77 errno);
78 }
79
80 if (((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0)
81 return;
82
83 bad_wait:
84 err = ptrace_dump_regs(pid);
85 if (err)
86 printk(UM_KERN_ERR "Failed to get registers from stub, "
87 "errno = %d\n", -err);
88 panic("wait_stub_done : failed to wait for SIGUSR1/SIGTRAP, pid = %d, "
89 "n = %d, errno = %d, status = 0x%x\n", pid, n, errno, status);
90 }
91
92 extern unsigned long current_stub_stack(void);
93
94 void get_skas_faultinfo(int pid, struct faultinfo * fi)
95 {
96 int err;
97
98 if (ptrace_faultinfo) {
99 err = ptrace(PTRACE_FAULTINFO, pid, 0, fi);
100 if (err)
101 panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, "
102 "errno = %d\n", errno);
103
104 /* Special handling for i386, which has different structs */
105 if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo))
106 memset((char *)fi + sizeof(struct ptrace_faultinfo), 0,
107 sizeof(struct faultinfo) -
108 sizeof(struct ptrace_faultinfo));
109 }
110 else {
111 err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV);
112 if (err)
113 panic("Failed to continue stub, pid = %d, errno = %d\n",
114 pid, errno);
115 wait_stub_done(pid);
116
117 /*
118 * faultinfo is prepared by the stub-segv-handler at start of
119 * the stub stack page. We just have to copy it.
120 */
121 memcpy(fi, (void *)current_stub_stack(), sizeof(*fi));
122 }
123 }
124
125 static void handle_segv(int pid, struct uml_pt_regs * regs)
126 {
127 get_skas_faultinfo(pid, &regs->faultinfo);
128 segv(regs->faultinfo, 0, 1, NULL);
129 }
130
131 /*
132 * To use the same value of using_sysemu as the caller, ask it that value
133 * (in local_using_sysemu
134 */
135 static void handle_trap(int pid, struct uml_pt_regs *regs,
136 int local_using_sysemu)
137 {
138 int err, status;
139
140 /* Mark this as a syscall */
141 UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->gp);
142
143 if (!local_using_sysemu)
144 {
145 err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
146 __NR_getpid);
147 if (err < 0)
148 panic("handle_trap - nullifying syscall failed, "
149 "errno = %d\n", errno);
150
151 err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
152 if (err < 0)
153 panic("handle_trap - continuing to end of syscall "
154 "failed, errno = %d\n", errno);
155
156 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
157 if ((err < 0) || !WIFSTOPPED(status) ||
158 (WSTOPSIG(status) != SIGTRAP + 0x80)) {
159 err = ptrace_dump_regs(pid);
160 if (err)
161 printk(UM_KERN_ERR "Failed to get registers "
162 "from process, errno = %d\n", -err);
163 panic("handle_trap - failed to wait at end of syscall, "
164 "errno = %d, status = %d\n", errno, status);
165 }
166 }
167
168 handle_syscall(regs);
169 }
170
171 extern int __syscall_stub_start;
172
173 static int userspace_tramp(void *stack)
174 {
175 void *addr;
176 int err;
177
178 ptrace(PTRACE_TRACEME, 0, 0, 0);
179
180 signal(SIGTERM, SIG_DFL);
181 err = set_interval();
182 if (err)
183 panic("userspace_tramp - setting timer failed, errno = %d\n",
184 err);
185
186 if (!proc_mm) {
187 /*
188 * This has a pte, but it can't be mapped in with the usual
189 * tlb_flush mechanism because this is part of that mechanism
190 */
191 int fd;
192 unsigned long long offset;
193 fd = phys_mapping(to_phys(&__syscall_stub_start), &offset);
194 addr = mmap64((void *) STUB_CODE, UM_KERN_PAGE_SIZE,
195 PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
196 if (addr == MAP_FAILED) {
197 printk(UM_KERN_ERR "mapping mmap stub at 0x%lx failed, "
198 "errno = %d\n", STUB_CODE, errno);
199 exit(1);
200 }
201
202 if (stack != NULL) {
203 fd = phys_mapping(to_phys(stack), &offset);
204 addr = mmap((void *) STUB_DATA,
205 UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
206 MAP_FIXED | MAP_SHARED, fd, offset);
207 if (addr == MAP_FAILED) {
208 printk(UM_KERN_ERR "mapping segfault stack "
209 "at 0x%lx failed, errno = %d\n",
210 STUB_DATA, errno);
211 exit(1);
212 }
213 }
214 }
215 if (!ptrace_faultinfo && (stack != NULL)) {
216 struct sigaction sa;
217
218 unsigned long v = STUB_CODE +
219 (unsigned long) stub_segv_handler -
220 (unsigned long) &__syscall_stub_start;
221
222 set_sigstack((void *) STUB_DATA, UM_KERN_PAGE_SIZE);
223 sigemptyset(&sa.sa_mask);
224 sigaddset(&sa.sa_mask, SIGIO);
225 sigaddset(&sa.sa_mask, SIGWINCH);
226 sigaddset(&sa.sa_mask, SIGVTALRM);
227 sigaddset(&sa.sa_mask, SIGUSR1);
228 sa.sa_flags = SA_ONSTACK;
229 sa.sa_handler = (void *) v;
230 sa.sa_restorer = NULL;
231 if (sigaction(SIGSEGV, &sa, NULL) < 0)
232 panic("userspace_tramp - setting SIGSEGV handler "
233 "failed - errno = %d\n", errno);
234 }
235
236 kill(os_getpid(), SIGSTOP);
237 return 0;
238 }
239
240 /* Each element set once, and only accessed by a single processor anyway */
241 #undef NR_CPUS
242 #define NR_CPUS 1
243 int userspace_pid[NR_CPUS];
244
245 int start_userspace(unsigned long stub_stack)
246 {
247 void *stack;
248 unsigned long sp;
249 int pid, status, n, flags;
250
251 stack = mmap(NULL, UM_KERN_PAGE_SIZE,
252 PROT_READ | PROT_WRITE | PROT_EXEC,
253 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
254 if (stack == MAP_FAILED)
255 panic("start_userspace : mmap failed, errno = %d", errno);
256 sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *);
257
258 flags = CLONE_FILES;
259 if (proc_mm)
260 flags |= CLONE_VM;
261 else
262 flags |= SIGCHLD;
263
264 pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
265 if (pid < 0)
266 panic("start_userspace : clone failed, errno = %d", errno);
267
268 do {
269 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED | __WALL));
270 if (n < 0)
271 panic("start_userspace : wait failed, errno = %d",
272 errno);
273 } while (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM));
274
275 if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
276 panic("start_userspace : expected SIGSTOP, got status = %d",
277 status);
278
279 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
280 (void *) PTRACE_O_TRACESYSGOOD) < 0)
281 panic("start_userspace : PTRACE_OLDSETOPTIONS failed, "
282 "errno = %d\n", errno);
283
284 if (munmap(stack, UM_KERN_PAGE_SIZE) < 0)
285 panic("start_userspace : munmap failed, errno = %d\n", errno);
286
287 return pid;
288 }
289
290 void userspace(struct uml_pt_regs *regs)
291 {
292 struct itimerval timer;
293 unsigned long long nsecs, now;
294 int err, status, op, pid = userspace_pid[0];
295 /* To prevent races if using_sysemu changes under us.*/
296 int local_using_sysemu;
297
298 if (getitimer(ITIMER_VIRTUAL, &timer))
299 printk("Failed to get itimer, errno = %d\n", errno);
300 nsecs = timer.it_value.tv_sec * UM_NSEC_PER_SEC +
301 timer.it_value.tv_usec * UM_NSEC_PER_USEC;
302 nsecs += os_nsecs();
303
304 while (1) {
305 restore_registers(pid, regs);
306
307 /* Now we set local_using_sysemu to be used for one loop */
308 local_using_sysemu = get_using_sysemu();
309
310 op = SELECT_PTRACE_OPERATION(local_using_sysemu,
311 singlestepping(NULL));
312
313 err = ptrace(op, pid, 0, 0);
314 if (err)
315 panic("userspace - could not resume userspace process, "
316 "pid=%d, ptrace operation = %d, errno = %d\n",
317 pid, op, errno);
318
319 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED | __WALL));
320 if (err < 0)
321 panic("userspace - waitpid failed, errno = %d\n",
322 errno);
323
324 regs->is_user = 1;
325 save_registers(pid, regs);
326 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
327
328 if (WIFSTOPPED(status)) {
329 int sig = WSTOPSIG(status);
330 switch(sig) {
331 case SIGSEGV:
332 if (PTRACE_FULL_FAULTINFO ||
333 !ptrace_faultinfo) {
334 get_skas_faultinfo(pid,
335 &regs->faultinfo);
336 (*sig_info[SIGSEGV])(SIGSEGV, regs);
337 }
338 else handle_segv(pid, regs);
339 break;
340 case SIGTRAP + 0x80:
341 handle_trap(pid, regs, local_using_sysemu);
342 break;
343 case SIGTRAP:
344 relay_signal(SIGTRAP, regs);
345 break;
346 case SIGVTALRM:
347 now = os_nsecs();
348 if(now < nsecs)
349 break;
350 block_signals();
351 (*sig_info[sig])(sig, regs);
352 unblock_signals();
353 nsecs = timer.it_value.tv_sec *
354 UM_NSEC_PER_SEC +
355 timer.it_value.tv_usec *
356 UM_NSEC_PER_USEC;
357 nsecs += os_nsecs();
358 break;
359 case SIGIO:
360 case SIGILL:
361 case SIGBUS:
362 case SIGFPE:
363 case SIGWINCH:
364 block_signals();
365 (*sig_info[sig])(sig, regs);
366 unblock_signals();
367 break;
368 default:
369 printk(UM_KERN_ERR "userspace - child stopped "
370 "with signal %d\n", sig);
371 }
372 pid = userspace_pid[0];
373 interrupt_end();
374
375 /* Avoid -ERESTARTSYS handling in host */
376 if (PT_SYSCALL_NR_OFFSET != PT_SYSCALL_RET_OFFSET)
377 PT_SYSCALL_NR(regs->gp) = -1;
378 }
379 }
380 }
381
382 static unsigned long thread_regs[MAX_REG_NR];
383
384 static int __init init_thread_regs(void)
385 {
386 get_safe_registers(thread_regs);
387 /* Set parent's instruction pointer to start of clone-stub */
388 thread_regs[REGS_IP_INDEX] = STUB_CODE +
389 (unsigned long) stub_clone_handler -
390 (unsigned long) &__syscall_stub_start;
391 thread_regs[REGS_SP_INDEX] = STUB_DATA + UM_KERN_PAGE_SIZE -
392 sizeof(void *);
393 #ifdef __SIGNAL_FRAMESIZE
394 thread_regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
395 #endif
396 return 0;
397 }
398
399 __initcall(init_thread_regs);
400
401 int copy_context_skas0(unsigned long new_stack, int pid)
402 {
403 struct timeval tv = { .tv_sec = 0, .tv_usec = UM_USEC_PER_SEC / UM_HZ };
404 int err;
405 unsigned long current_stack = current_stub_stack();
406 struct stub_data *data = (struct stub_data *) current_stack;
407 struct stub_data *child_data = (struct stub_data *) new_stack;
408 unsigned long long new_offset;
409 int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset);
410
411 /*
412 * prepare offset and fd of child's stack as argument for parent's
413 * and child's mmap2 calls
414 */
415 *data = ((struct stub_data) { .offset = MMAP_OFFSET(new_offset),
416 .fd = new_fd,
417 .timer = ((struct itimerval)
418 { .it_value = tv,
419 .it_interval = tv }) });
420
421 err = ptrace_setregs(pid, thread_regs);
422 if (err < 0)
423 panic("copy_context_skas0 : PTRACE_SETREGS failed, "
424 "pid = %d, errno = %d\n", pid, -err);
425
426 /* set a well known return code for detection of child write failure */
427 child_data->err = 12345678;
428
429 /*
430 * Wait, until parent has finished its work: read child's pid from
431 * parent's stack, and check, if bad result.
432 */
433 err = ptrace(PTRACE_CONT, pid, 0, 0);
434 if (err)
435 panic("Failed to continue new process, pid = %d, "
436 "errno = %d\n", pid, errno);
437 wait_stub_done(pid);
438
439 pid = data->err;
440 if (pid < 0)
441 panic("copy_context_skas0 - stub-parent reports error %d\n",
442 -pid);
443
444 /*
445 * Wait, until child has finished too: read child's result from
446 * child's stack and check it.
447 */
448 wait_stub_done(pid);
449 if (child_data->err != STUB_DATA)
450 panic("copy_context_skas0 - stub-child reports error %ld\n",
451 child_data->err);
452
453 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
454 (void *)PTRACE_O_TRACESYSGOOD) < 0)
455 panic("copy_context_skas0 : PTRACE_OLDSETOPTIONS failed, "
456 "errno = %d\n", errno);
457
458 return pid;
459 }
460
461 /*
462 * This is used only, if stub pages are needed, while proc_mm is
463 * available. Opening /proc/mm creates a new mm_context, which lacks
464 * the stub-pages. Thus, we map them using /proc/mm-fd
465 */
466 void map_stub_pages(int fd, unsigned long code,
467 unsigned long data, unsigned long stack)
468 {
469 struct proc_mm_op mmop;
470 int n;
471 unsigned long long code_offset;
472 int code_fd = phys_mapping(to_phys((void *) &__syscall_stub_start),
473 &code_offset);
474
475 mmop = ((struct proc_mm_op) { .op = MM_MMAP,
476 .u =
477 { .mmap =
478 { .addr = code,
479 .len = UM_KERN_PAGE_SIZE,
480 .prot = PROT_EXEC,
481 .flags = MAP_FIXED | MAP_PRIVATE,
482 .fd = code_fd,
483 .offset = code_offset
484 } } });
485 CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop)));
486 if (n != sizeof(mmop)) {
487 n = errno;
488 printk(UM_KERN_ERR "mmap args - addr = 0x%lx, fd = %d, "
489 "offset = %llx\n", code, code_fd,
490 (unsigned long long) code_offset);
491 panic("map_stub_pages : /proc/mm map for code failed, "
492 "err = %d\n", n);
493 }
494
495 if (stack) {
496 unsigned long long map_offset;
497 int map_fd = phys_mapping(to_phys((void *)stack), &map_offset);
498 mmop = ((struct proc_mm_op)
499 { .op = MM_MMAP,
500 .u =
501 { .mmap =
502 { .addr = data,
503 .len = UM_KERN_PAGE_SIZE,
504 .prot = PROT_READ | PROT_WRITE,
505 .flags = MAP_FIXED | MAP_SHARED,
506 .fd = map_fd,
507 .offset = map_offset
508 } } });
509 CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop)));
510 if (n != sizeof(mmop))
511 panic("map_stub_pages : /proc/mm map for data failed, "
512 "err = %d\n", errno);
513 }
514 }
515
516 void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
517 {
518 (*buf)[0].JB_IP = (unsigned long) handler;
519 (*buf)[0].JB_SP = (unsigned long) stack + UM_THREAD_SIZE -
520 sizeof(void *);
521 }
522
523 #define INIT_JMP_NEW_THREAD 0
524 #define INIT_JMP_CALLBACK 1
525 #define INIT_JMP_HALT 2
526 #define INIT_JMP_REBOOT 3
527
528 void switch_threads(jmp_buf *me, jmp_buf *you)
529 {
530 if (UML_SETJMP(me) == 0)
531 UML_LONGJMP(you, 1);
532 }
533
534 static jmp_buf initial_jmpbuf;
535
536 /* XXX Make these percpu */
537 static void (*cb_proc)(void *arg);
538 static void *cb_arg;
539 static jmp_buf *cb_back;
540
541 int start_idle_thread(void *stack, jmp_buf *switch_buf)
542 {
543 int n;
544
545 set_handler(SIGWINCH, (__sighandler_t) sig_handler,
546 SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGVTALRM, -1);
547
548 /*
549 * Can't use UML_SETJMP or UML_LONGJMP here because they save
550 * and restore signals, with the possible side-effect of
551 * trying to handle any signals which came when they were
552 * blocked, which can't be done on this stack.
553 * Signals must be blocked when jumping back here and restored
554 * after returning to the jumper.
555 */
556 n = setjmp(initial_jmpbuf);
557 switch(n) {
558 case INIT_JMP_NEW_THREAD:
559 (*switch_buf)[0].JB_IP = (unsigned long) new_thread_handler;
560 (*switch_buf)[0].JB_SP = (unsigned long) stack +
561 UM_THREAD_SIZE - sizeof(void *);
562 break;
563 case INIT_JMP_CALLBACK:
564 (*cb_proc)(cb_arg);
565 longjmp(*cb_back, 1);
566 break;
567 case INIT_JMP_HALT:
568 kmalloc_ok = 0;
569 return 0;
570 case INIT_JMP_REBOOT:
571 kmalloc_ok = 0;
572 return 1;
573 default:
574 panic("Bad sigsetjmp return in start_idle_thread - %d\n", n);
575 }
576 longjmp(*switch_buf, 1);
577 }
578
579 void initial_thread_cb_skas(void (*proc)(void *), void *arg)
580 {
581 jmp_buf here;
582
583 cb_proc = proc;
584 cb_arg = arg;
585 cb_back = &here;
586
587 block_signals();
588 if (UML_SETJMP(&here) == 0)
589 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK);
590 unblock_signals();
591
592 cb_proc = NULL;
593 cb_arg = NULL;
594 cb_back = NULL;
595 }
596
597 void halt_skas(void)
598 {
599 block_signals();
600 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT);
601 }
602
603 void reboot_skas(void)
604 {
605 block_signals();
606 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_REBOOT);
607 }
608
609 void __switch_mm(struct mm_id *mm_idp)
610 {
611 int err;
612
613 /* FIXME: need cpu pid in __switch_mm */
614 if (proc_mm) {
615 err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0,
616 mm_idp->u.mm_fd);
617 if (err)
618 panic("__switch_mm - PTRACE_SWITCH_MM failed, "
619 "errno = %d\n", errno);
620 }
621 else userspace_pid[0] = mm_idp->u.pid;
622 }
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