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[IPV4]: Correct rp_filter help text.
[linux-2.6/verdex.git] / arch / um / os-Linux / skas / process.c
blobf9d2f8545afedd12f06a2e3a216eea2757759999
1 /*
2 * Copyright (C) 2002- 2004 Jeff Dike (jdike@addtoit.com)
3 * Licensed under the GPL
4 */
5
6 #include <stdlib.h>
7 #include <string.h>
8 #include <unistd.h>
9 #include <errno.h>
10 #include <signal.h>
11 #include <sched.h>
12 #include "ptrace_user.h"
13 #include <sys/wait.h>
14 #include <sys/mman.h>
15 #include <sys/user.h>
16 #include <sys/time.h>
17 #include <sys/syscall.h>
18 #include <asm/types.h>
19 #include "user.h"
20 #include "sysdep/ptrace.h"
21 #include "kern_util.h"
22 #include "skas.h"
23 #include "stub-data.h"
24 #include "mm_id.h"
25 #include "sysdep/sigcontext.h"
26 #include "sysdep/stub.h"
27 #include "os.h"
28 #include "proc_mm.h"
29 #include "skas_ptrace.h"
30 #include "chan_user.h"
31 #include "registers.h"
32 #include "mem.h"
33 #include "uml-config.h"
34 #include "process.h"
35 #include "longjmp.h"
36 #include "kern_constants.h"
37 #include "as-layout.h"
38
39 int is_skas_winch(int pid, int fd, void *data)
40 {
41 if(pid != os_getpgrp())
42 return(0);
43
44 register_winch_irq(-1, fd, -1, data);
45 return(1);
46 }
47
48 static int ptrace_dump_regs(int pid)
49 {
50 unsigned long regs[MAX_REG_NR];
51 int i;
52
53 if(ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
54 return -errno;
55 else {
56 printk("Stub registers -\n");
57 for(i = 0; i < ARRAY_SIZE(regs); i++)
58 printk("\t%d - %lx\n", i, regs[i]);
59 }
60
61 return 0;
62 }
63
64 /*
65 * Signals that are OK to receive in the stub - we'll just continue it.
66 * SIGWINCH will happen when UML is inside a detached screen.
67 */
68 #define STUB_SIG_MASK ((1 << SIGVTALRM) | (1 << SIGWINCH))
69
70 /* Signals that the stub will finish with - anything else is an error */
71 #define STUB_DONE_MASK ((1 << SIGUSR1) | (1 << SIGTRAP))
72
73 void wait_stub_done(int pid)
74 {
75 int n, status, err;
76
77 while(1){
78 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
79 if((n < 0) || !WIFSTOPPED(status))
80 goto bad_wait;
81
82 if(((1 << WSTOPSIG(status)) & STUB_SIG_MASK) == 0)
83 break;
84
85 err = ptrace(PTRACE_CONT, pid, 0, 0);
86 if(err)
87 panic("wait_stub_done : continue failed, errno = %d\n",
88 errno);
89 }
90
91 if(((1 << WSTOPSIG(status)) & STUB_DONE_MASK) != 0)
92 return;
93
94 bad_wait:
95 err = ptrace_dump_regs(pid);
96 if(err)
97 printk("Failed to get registers from stub, errno = %d\n", -err);
98 panic("wait_stub_done : failed to wait for SIGUSR1/SIGTRAP, pid = %d, "
99 "n = %d, errno = %d, status = 0x%x\n", pid, n, errno, status);
100 }
101
102 extern unsigned long current_stub_stack(void);
103
104 void get_skas_faultinfo(int pid, struct faultinfo * fi)
105 {
106 int err;
107
108 if(ptrace_faultinfo){
109 err = ptrace(PTRACE_FAULTINFO, pid, 0, fi);
110 if(err)
111 panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, "
112 "errno = %d\n", errno);
113
114 /* Special handling for i386, which has different structs */
115 if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo))
116 memset((char *)fi + sizeof(struct ptrace_faultinfo), 0,
117 sizeof(struct faultinfo) -
118 sizeof(struct ptrace_faultinfo));
119 }
120 else {
121 err = ptrace(PTRACE_CONT, pid, 0, SIGSEGV);
122 if(err)
123 panic("Failed to continue stub, pid = %d, errno = %d\n",
124 pid, errno);
125 wait_stub_done(pid);
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 }
133
134 static void handle_segv(int pid, union uml_pt_regs * regs)
135 {
136 get_skas_faultinfo(pid, &regs->skas.faultinfo);
137 segv(regs->skas.faultinfo, 0, 1, NULL);
138 }
139
140 /*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/
141 static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu)
142 {
143 int err, status;
144
145 /* Mark this as a syscall */
146 UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->skas.regs);
147
148 if (!local_using_sysemu)
149 {
150 err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
151 __NR_getpid);
152 if(err < 0)
153 panic("handle_trap - nullifying syscall failed errno = %d\n",
154 errno);
155
156 err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
157 if(err < 0)
158 panic("handle_trap - continuing to end of syscall failed, "
159 "errno = %d\n", errno);
160
161 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
162 if((err < 0) || !WIFSTOPPED(status) ||
163 (WSTOPSIG(status) != SIGTRAP + 0x80)){
164 err = ptrace_dump_regs(pid);
165 if(err)
166 printk("Failed to get registers from process, "
167 "errno = %d\n", -err);
168 panic("handle_trap - failed to wait at end of syscall, "
169 "errno = %d, status = %d\n", errno, status);
170 }
171 }
172
173 handle_syscall(regs);
174 }
175
176 extern int __syscall_stub_start;
177
178 static int userspace_tramp(void *stack)
179 {
180 void *addr;
181 int err;
182
183 ptrace(PTRACE_TRACEME, 0, 0, 0);
184
185 init_new_thread_signals();
186 err = set_interval(1);
187 if(err)
188 panic("userspace_tramp - setting timer failed, errno = %d\n",
189 err);
190
191 if(!proc_mm){
192 /* This has a pte, but it can't be mapped in with the usual
193 * tlb_flush mechanism because this is part of that mechanism
194 */
195 int fd;
196 __u64 offset;
197 fd = phys_mapping(to_phys(&__syscall_stub_start), &offset);
198 addr = mmap64((void *) UML_CONFIG_STUB_CODE, UM_KERN_PAGE_SIZE,
199 PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
200 if(addr == MAP_FAILED){
201 printk("mapping mmap stub failed, errno = %d\n",
202 errno);
203 exit(1);
204 }
205
206 if(stack != NULL){
207 fd = phys_mapping(to_phys(stack), &offset);
208 addr = mmap((void *) UML_CONFIG_STUB_DATA,
209 UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
210 MAP_FIXED | MAP_SHARED, fd, offset);
211 if(addr == MAP_FAILED){
212 printk("mapping segfault stack failed, "
213 "errno = %d\n", errno);
214 exit(1);
215 }
216 }
217 }
218 if(!ptrace_faultinfo && (stack != NULL)){
219 struct sigaction sa;
220
221 unsigned long v = UML_CONFIG_STUB_CODE +
222 (unsigned long) stub_segv_handler -
223 (unsigned long) &__syscall_stub_start;
224
225 set_sigstack((void *) UML_CONFIG_STUB_DATA, UM_KERN_PAGE_SIZE);
226 sigemptyset(&sa.sa_mask);
227 sigaddset(&sa.sa_mask, SIGIO);
228 sigaddset(&sa.sa_mask, SIGWINCH);
229 sigaddset(&sa.sa_mask, SIGALRM);
230 sigaddset(&sa.sa_mask, SIGVTALRM);
231 sigaddset(&sa.sa_mask, SIGUSR1);
232 sa.sa_flags = SA_ONSTACK;
233 sa.sa_handler = (void *) v;
234 sa.sa_restorer = NULL;
235 if(sigaction(SIGSEGV, &sa, NULL) < 0)
236 panic("userspace_tramp - setting SIGSEGV handler "
237 "failed - errno = %d\n", errno);
238 }
239
240 os_stop_process(os_getpid());
241 return(0);
242 }
243
244 /* Each element set once, and only accessed by a single processor anyway */
245 #undef NR_CPUS
246 #define NR_CPUS 1
247 int userspace_pid[NR_CPUS];
248
249 int start_userspace(unsigned long stub_stack)
250 {
251 void *stack;
252 unsigned long sp;
253 int pid, status, n, flags;
254
255 stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC,
256 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
257 if(stack == MAP_FAILED)
258 panic("start_userspace : mmap failed, errno = %d", errno);
259 sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *);
260
261 flags = CLONE_FILES | SIGCHLD;
262 if(proc_mm) flags |= CLONE_VM;
263 pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
264 if(pid < 0)
265 panic("start_userspace : clone failed, errno = %d", errno);
266
267 do {
268 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
269 if(n < 0)
270 panic("start_userspace : wait failed, errno = %d",
271 errno);
272 } while(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM));
273
274 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
275 panic("start_userspace : expected SIGSTOP, got status = %d",
276 status);
277
278 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, (void *)PTRACE_O_TRACESYSGOOD) < 0)
279 panic("start_userspace : PTRACE_OLDSETOPTIONS failed, errno=%d\n",
280 errno);
281
282 if(munmap(stack, PAGE_SIZE) < 0)
283 panic("start_userspace : munmap failed, errno = %d\n", errno);
284
285 return(pid);
286 }
287
288 void userspace(union uml_pt_regs *regs)
289 {
290 int err, status, op, pid = userspace_pid[0];
291 /* To prevent races if using_sysemu changes under us.*/
292 int local_using_sysemu;
293
294 while(1){
295 restore_registers(pid, regs);
296
297 /* Now we set local_using_sysemu to be used for one loop */
298 local_using_sysemu = get_using_sysemu();
299
300 op = SELECT_PTRACE_OPERATION(local_using_sysemu,
301 singlestepping(NULL));
302
303 err = ptrace(op, pid, 0, 0);
304 if(err)
305 panic("userspace - could not resume userspace process, "
306 "pid=%d, ptrace operation = %d, errno = %d\n",
307 pid, op, errno);
308
309 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
310 if(err < 0)
311 panic("userspace - waitpid failed, errno = %d\n",
312 errno);
313
314 regs->skas.is_user = 1;
315 save_registers(pid, regs);
316 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
317
318 if(WIFSTOPPED(status)){
319 int sig = WSTOPSIG(status);
320 switch(sig){
321 case SIGSEGV:
322 if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo){
323 get_skas_faultinfo(pid, &regs->skas.faultinfo);
324 (*sig_info[SIGSEGV])(SIGSEGV, regs);
325 }
326 else handle_segv(pid, regs);
327 break;
328 case SIGTRAP + 0x80:
329 handle_trap(pid, regs, local_using_sysemu);
330 break;
331 case SIGTRAP:
332 relay_signal(SIGTRAP, regs);
333 break;
334 case SIGIO:
335 case SIGVTALRM:
336 case SIGILL:
337 case SIGBUS:
338 case SIGFPE:
339 case SIGWINCH:
340 block_signals();
341 (*sig_info[sig])(sig, regs);
342 unblock_signals();
343 break;
344 default:
345 printk("userspace - child stopped with signal "
346 "%d\n", sig);
347 }
348 pid = userspace_pid[0];
349 interrupt_end();
350
351 /* Avoid -ERESTARTSYS handling in host */
352 if(PT_SYSCALL_NR_OFFSET != PT_SYSCALL_RET_OFFSET)
353 PT_SYSCALL_NR(regs->skas.regs) = -1;
354 }
355 }
356 }
357
358 static unsigned long thread_regs[MAX_REG_NR];
359 static unsigned long thread_fp_regs[HOST_FP_SIZE];
360
361 static int __init init_thread_regs(void)
362 {
363 get_safe_registers(thread_regs, thread_fp_regs);
364 /* Set parent's instruction pointer to start of clone-stub */
365 thread_regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
366 (unsigned long) stub_clone_handler -
367 (unsigned long) &__syscall_stub_start;
368 thread_regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE -
369 sizeof(void *);
370 #ifdef __SIGNAL_FRAMESIZE
371 thread_regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
372 #endif
373 return 0;
374 }
375
376 __initcall(init_thread_regs);
377
378 int copy_context_skas0(unsigned long new_stack, int pid)
379 {
380 int err;
381 unsigned long current_stack = current_stub_stack();
382 struct stub_data *data = (struct stub_data *) current_stack;
383 struct stub_data *child_data = (struct stub_data *) new_stack;
384 __u64 new_offset;
385 int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset);
386
387 /* prepare offset and fd of child's stack as argument for parent's
388 * and child's mmap2 calls
389 */
390 *data = ((struct stub_data) { .offset = MMAP_OFFSET(new_offset),
391 .fd = new_fd,
392 .timer = ((struct itimerval)
393 { { 0, 1000000 / hz() },
394 { 0, 1000000 / hz() }})});
395 err = ptrace_setregs(pid, thread_regs);
396 if(err < 0)
397 panic("copy_context_skas0 : PTRACE_SETREGS failed, "
398 "pid = %d, errno = %d\n", pid, -err);
399
400 err = ptrace_setfpregs(pid, thread_fp_regs);
401 if(err < 0)
402 panic("copy_context_skas0 : PTRACE_SETFPREGS failed, "
403 "pid = %d, errno = %d\n", pid, -err);
404
405 /* set a well known return code for detection of child write failure */
406 child_data->err = 12345678;
407
408 /* Wait, until parent has finished its work: read child's pid from
409 * parent's stack, and check, if bad result.
410 */
411 err = ptrace(PTRACE_CONT, pid, 0, 0);
412 if(err)
413 panic("Failed to continue new process, pid = %d, "
414 "errno = %d\n", pid, errno);
415 wait_stub_done(pid);
416
417 pid = data->err;
418 if(pid < 0)
419 panic("copy_context_skas0 - stub-parent reports error %d\n",
420 -pid);
421
422 /* Wait, until child has finished too: read child's result from
423 * child's stack and check it.
424 */
425 wait_stub_done(pid);
426 if (child_data->err != UML_CONFIG_STUB_DATA)
427 panic("copy_context_skas0 - stub-child reports error %ld\n",
428 child_data->err);
429
430 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
431 (void *)PTRACE_O_TRACESYSGOOD) < 0)
432 panic("copy_context_skas0 : PTRACE_OLDSETOPTIONS failed, "
433 "errno = %d\n", errno);
434
435 return pid;
436 }
437
438 /*
439 * This is used only, if stub pages are needed, while proc_mm is
440 * available. Opening /proc/mm creates a new mm_context, which lacks
441 * the stub-pages. Thus, we map them using /proc/mm-fd
442 */
443 void map_stub_pages(int fd, unsigned long code,
444 unsigned long data, unsigned long stack)
445 {
446 struct proc_mm_op mmop;
447 int n;
448 __u64 code_offset;
449 int code_fd = phys_mapping(to_phys((void *) &__syscall_stub_start),
450 &code_offset);
451
452 mmop = ((struct proc_mm_op) { .op = MM_MMAP,
453 .u =
454 { .mmap =
455 { .addr = code,
456 .len = PAGE_SIZE,
457 .prot = PROT_EXEC,
458 .flags = MAP_FIXED | MAP_PRIVATE,
459 .fd = code_fd,
460 .offset = code_offset
461 } } });
462 CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop)));
463 if(n != sizeof(mmop)){
464 n = errno;
465 printk("mmap args - addr = 0x%lx, fd = %d, offset = %llx\n",
466 code, code_fd, (unsigned long long) code_offset);
467 panic("map_stub_pages : /proc/mm map for code failed, "
468 "err = %d\n", n);
469 }
470
471 if ( stack ) {
472 __u64 map_offset;
473 int map_fd = phys_mapping(to_phys((void *)stack), &map_offset);
474 mmop = ((struct proc_mm_op)
475 { .op = MM_MMAP,
476 .u =
477 { .mmap =
478 { .addr = data,
479 .len = PAGE_SIZE,
480 .prot = PROT_READ | PROT_WRITE,
481 .flags = MAP_FIXED | MAP_SHARED,
482 .fd = map_fd,
483 .offset = map_offset
484 } } });
485 CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop)));
486 if(n != sizeof(mmop))
487 panic("map_stub_pages : /proc/mm map for data failed, "
488 "err = %d\n", errno);
489 }
490 }
491
492 void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
493 {
494 (*buf)[0].JB_IP = (unsigned long) handler;
495 (*buf)[0].JB_SP = (unsigned long) stack + UM_THREAD_SIZE -
496 sizeof(void *);
497 }
498
499 #define INIT_JMP_NEW_THREAD 0
500 #define INIT_JMP_CALLBACK 1
501 #define INIT_JMP_HALT 2
502 #define INIT_JMP_REBOOT 3
503
504 void switch_threads(jmp_buf *me, jmp_buf *you)
505 {
506 if(UML_SETJMP(me) == 0)
507 UML_LONGJMP(you, 1);
508 }
509
510 static jmp_buf initial_jmpbuf;
511
512 /* XXX Make these percpu */
513 static void (*cb_proc)(void *arg);
514 static void *cb_arg;
515 static jmp_buf *cb_back;
516
517 int start_idle_thread(void *stack, jmp_buf *switch_buf)
518 {
519 int n;
520
521 set_handler(SIGWINCH, (__sighandler_t) sig_handler,
522 SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM,
523 SIGVTALRM, -1);
524
525 /*
526 * Can't use UML_SETJMP or UML_LONGJMP here because they save
527 * and restore signals, with the possible side-effect of
528 * trying to handle any signals which came when they were
529 * blocked, which can't be done on this stack.
530 * Signals must be blocked when jumping back here and restored
531 * after returning to the jumper.
532 */
533 n = setjmp(initial_jmpbuf);
534 switch(n){
535 case INIT_JMP_NEW_THREAD:
536 (*switch_buf)[0].JB_IP = (unsigned long) new_thread_handler;
537 (*switch_buf)[0].JB_SP = (unsigned long) stack +
538 UM_THREAD_SIZE - sizeof(void *);
539 break;
540 case INIT_JMP_CALLBACK:
541 (*cb_proc)(cb_arg);
542 longjmp(*cb_back, 1);
543 break;
544 case INIT_JMP_HALT:
545 kmalloc_ok = 0;
546 return(0);
547 case INIT_JMP_REBOOT:
548 kmalloc_ok = 0;
549 return(1);
550 default:
551 panic("Bad sigsetjmp return in start_idle_thread - %d\n", n);
552 }
553 longjmp(*switch_buf, 1);
554 }
555
556 void initial_thread_cb_skas(void (*proc)(void *), void *arg)
557 {
558 jmp_buf here;
559
560 cb_proc = proc;
561 cb_arg = arg;
562 cb_back = &here;
563
564 block_signals();
565 if(UML_SETJMP(&here) == 0)
566 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK);
567 unblock_signals();
568
569 cb_proc = NULL;
570 cb_arg = NULL;
571 cb_back = NULL;
572 }
573
574 void halt_skas(void)
575 {
576 block_signals();
577 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT);
578 }
579
580 void reboot_skas(void)
581 {
582 block_signals();
583 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_REBOOT);
584 }
585
586 void switch_mm_skas(struct mm_id *mm_idp)
587 {
588 int err;
589
590 /* FIXME: need cpu pid in switch_mm_skas */
591 if(proc_mm){
592 err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0,
593 mm_idp->u.mm_fd);
594 if(err)
595 panic("switch_mm_skas - PTRACE_SWITCH_MM failed, "
596 "errno = %d\n", errno);
597 }
598 else userspace_pid[0] = mm_idp->u.pid;
599 }
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