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[PATCH] uml: initialize process FP registers properly
[wandboard.git] / arch / um / kernel / skas / process.c
blobeea1c9c4bb0fcd531803dbd6f9bfb468ed87055f
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 <setjmp.h>
12 #include <sched.h>
13 #include <sys/wait.h>
14 #include <sys/mman.h>
15 #include <sys/user.h>
16 #include <sys/time.h>
17 #include <asm/unistd.h>
18 #include <asm/types.h>
19 #include "user.h"
20 #include "ptrace_user.h"
21 #include "sysdep/ptrace.h"
22 #include "user_util.h"
23 #include "kern_util.h"
24 #include "skas.h"
25 #include "stub-data.h"
26 #include "mm_id.h"
27 #include "sysdep/sigcontext.h"
28 #include "sysdep/stub.h"
29 #include "os.h"
30 #include "proc_mm.h"
31 #include "skas_ptrace.h"
32 #include "chan_user.h"
33 #include "registers.h"
34 #include "mem.h"
35 #include "uml-config.h"
36 #include "process.h"
37
38 int is_skas_winch(int pid, int fd, void *data)
39 {
40 if(pid != os_getpgrp())
41 return(0);
42
43 register_winch_irq(-1, fd, -1, data);
44 return(1);
45 }
46
47 void wait_stub_done(int pid, int sig, char * fname)
48 {
49 int n, status, err;
50
51 do {
52 if ( sig != -1 ) {
53 err = ptrace(PTRACE_CONT, pid, 0, sig);
54 if(err)
55 panic("%s : continue failed, errno = %d\n",
56 fname, errno);
57 }
58 sig = 0;
59
60 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
61 } while((n >= 0) && WIFSTOPPED(status) &&
62 ((WSTOPSIG(status) == SIGVTALRM) ||
63 /* running UML inside a detached screen can cause
64 * SIGWINCHes
65 */
66 (WSTOPSIG(status) == SIGWINCH)));
67
68 if((n < 0) || !WIFSTOPPED(status) ||
69 (WSTOPSIG(status) != SIGUSR1 && WSTOPSIG(status) != SIGTRAP)){
70 unsigned long regs[HOST_FRAME_SIZE];
71 if(ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
72 printk("Failed to get registers from stub, "
73 "errno = %d\n", errno);
74 else {
75 int i;
76
77 printk("Stub registers -\n");
78 for(i = 0; i < HOST_FRAME_SIZE; i++)
79 printk("\t%d - %lx\n", i, regs[i]);
80 }
81 panic("%s : failed to wait for SIGUSR1/SIGTRAP, "
82 "pid = %d, n = %d, errno = %d, status = 0x%x\n",
83 fname, pid, n, errno, status);
84 }
85 }
86
87 void get_skas_faultinfo(int pid, struct faultinfo * fi)
88 {
89 int err;
90
91 if(ptrace_faultinfo){
92 err = ptrace(PTRACE_FAULTINFO, pid, 0, fi);
93 if(err)
94 panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, "
95 "errno = %d\n", errno);
96
97 /* Special handling for i386, which has different structs */
98 if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo))
99 memset((char *)fi + sizeof(struct ptrace_faultinfo), 0,
100 sizeof(struct faultinfo) -
101 sizeof(struct ptrace_faultinfo));
102 }
103 else {
104 wait_stub_done(pid, SIGSEGV, "get_skas_faultinfo");
105
106 /* faultinfo is prepared by the stub-segv-handler at start of
107 * the stub stack page. We just have to copy it.
108 */
109 memcpy(fi, (void *)current_stub_stack(), sizeof(*fi));
110 }
111 }
112
113 static void handle_segv(int pid, union uml_pt_regs * regs)
114 {
115 get_skas_faultinfo(pid, &regs->skas.faultinfo);
116 segv(regs->skas.faultinfo, 0, 1, NULL);
117 }
118
119 /*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/
120 static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu)
121 {
122 int err, status;
123
124 /* Mark this as a syscall */
125 UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->skas.regs);
126
127 if (!local_using_sysemu)
128 {
129 err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET, __NR_getpid);
130 if(err < 0)
131 panic("handle_trap - nullifying syscall failed errno = %d\n",
132 errno);
133
134 err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
135 if(err < 0)
136 panic("handle_trap - continuing to end of syscall failed, "
137 "errno = %d\n", errno);
138
139 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
140 if((err < 0) || !WIFSTOPPED(status) ||
141 (WSTOPSIG(status) != SIGTRAP + 0x80))
142 panic("handle_trap - failed to wait at end of syscall, "
143 "errno = %d, status = %d\n", errno, status);
144 }
145
146 handle_syscall(regs);
147 }
148
149 extern int __syscall_stub_start;
150 int stub_code_fd = -1;
151 __u64 stub_code_offset;
152
153 static int userspace_tramp(void *stack)
154 {
155 void *addr;
156
157 ptrace(PTRACE_TRACEME, 0, 0, 0);
158
159 init_new_thread_signals(1);
160 enable_timer();
161
162 if(!proc_mm){
163 /* This has a pte, but it can't be mapped in with the usual
164 * tlb_flush mechanism because this is part of that mechanism
165 */
166 addr = mmap64((void *) UML_CONFIG_STUB_CODE, page_size(),
167 PROT_EXEC, MAP_FIXED | MAP_PRIVATE,
168 stub_code_fd, stub_code_offset);
169 if(addr == MAP_FAILED){
170 printk("mapping stub code failed, errno = %d\n",
171 errno);
172 exit(1);
173 }
174
175 if(stack != NULL){
176 int fd;
177 __u64 offset;
178
179 fd = phys_mapping(to_phys(stack), &offset);
180 addr = mmap((void *) UML_CONFIG_STUB_DATA, page_size(),
181 PROT_READ | PROT_WRITE,
182 MAP_FIXED | MAP_SHARED, fd, offset);
183 if(addr == MAP_FAILED){
184 printk("mapping stub stack failed, "
185 "errno = %d\n", errno);
186 exit(1);
187 }
188 }
189 }
190 if(!ptrace_faultinfo){
191 unsigned long v = UML_CONFIG_STUB_CODE +
192 (unsigned long) stub_segv_handler -
193 (unsigned long) &__syscall_stub_start;
194
195 set_sigstack((void *) UML_CONFIG_STUB_DATA, page_size());
196 set_handler(SIGSEGV, (void *) v, SA_ONSTACK,
197 SIGIO, SIGWINCH, SIGALRM, SIGVTALRM,
198 SIGUSR1, -1);
199 }
200
201 os_stop_process(os_getpid());
202 return(0);
203 }
204
205 /* Each element set once, and only accessed by a single processor anyway */
206 #undef NR_CPUS
207 #define NR_CPUS 1
208 int userspace_pid[NR_CPUS];
209
210 int start_userspace(unsigned long stub_stack)
211 {
212 void *stack;
213 unsigned long sp;
214 int pid, status, n, flags;
215
216 if ( stub_code_fd == -1 )
217 stub_code_fd = phys_mapping(to_phys(&__syscall_stub_start),
218 &stub_code_offset);
219
220 stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC,
221 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
222 if(stack == MAP_FAILED)
223 panic("start_userspace : mmap failed, errno = %d", errno);
224 sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *);
225
226 flags = CLONE_FILES | SIGCHLD;
227 if(proc_mm) flags |= CLONE_VM;
228 pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
229 if(pid < 0)
230 panic("start_userspace : clone failed, errno = %d", errno);
231
232 do {
233 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
234 if(n < 0)
235 panic("start_userspace : wait failed, errno = %d",
236 errno);
237 } while(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM));
238
239 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
240 panic("start_userspace : expected SIGSTOP, got status = %d",
241 status);
242
243 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, (void *)PTRACE_O_TRACESYSGOOD) < 0)
244 panic("start_userspace : PTRACE_SETOPTIONS failed, errno=%d\n",
245 errno);
246
247 if(munmap(stack, PAGE_SIZE) < 0)
248 panic("start_userspace : munmap failed, errno = %d\n", errno);
249
250 return(pid);
251 }
252
253 void userspace(union uml_pt_regs *regs)
254 {
255 int err, status, op, pid = userspace_pid[0];
256 int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/
257
258 while(1){
259 restore_registers(pid, regs);
260
261 /* Now we set local_using_sysemu to be used for one loop */
262 local_using_sysemu = get_using_sysemu();
263
264 op = SELECT_PTRACE_OPERATION(local_using_sysemu, singlestepping(NULL));
265
266 err = ptrace(op, pid, 0, 0);
267 if(err)
268 panic("userspace - could not resume userspace process, "
269 "pid=%d, ptrace operation = %d, errno = %d\n",
270 op, errno);
271
272 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
273 if(err < 0)
274 panic("userspace - waitpid failed, errno = %d\n",
275 errno);
276
277 regs->skas.is_user = 1;
278 save_registers(pid, regs);
279 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
280
281 if(WIFSTOPPED(status)){
282 switch(WSTOPSIG(status)){
283 case SIGSEGV:
284 if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo)
285 user_signal(SIGSEGV, regs, pid);
286 else handle_segv(pid, regs);
287 break;
288 case SIGTRAP + 0x80:
289 handle_trap(pid, regs, local_using_sysemu);
290 break;
291 case SIGTRAP:
292 relay_signal(SIGTRAP, regs);
293 break;
294 case SIGIO:
295 case SIGVTALRM:
296 case SIGILL:
297 case SIGBUS:
298 case SIGFPE:
299 case SIGWINCH:
300 user_signal(WSTOPSIG(status), regs, pid);
301 break;
302 default:
303 printk("userspace - child stopped with signal "
304 "%d\n", WSTOPSIG(status));
305 }
306 pid = userspace_pid[0];
307 interrupt_end();
308
309 /* Avoid -ERESTARTSYS handling in host */
310 PT_SYSCALL_NR(regs->skas.regs) = -1;
311 }
312 }
313 }
314 #define INIT_JMP_NEW_THREAD 0
315 #define INIT_JMP_REMOVE_SIGSTACK 1
316 #define INIT_JMP_CALLBACK 2
317 #define INIT_JMP_HALT 3
318 #define INIT_JMP_REBOOT 4
319
320
321 int copy_context_skas0(unsigned long new_stack, int pid)
322 {
323 int err;
324 unsigned long regs[MAX_REG_NR];
325 unsigned long current_stack = current_stub_stack();
326 struct stub_data *data = (struct stub_data *) current_stack;
327 struct stub_data *child_data = (struct stub_data *) new_stack;
328 __u64 new_offset;
329 int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset);
330
331 /* prepare offset and fd of child's stack as argument for parent's
332 * and child's mmap2 calls
333 */
334 *data = ((struct stub_data) { .offset = MMAP_OFFSET(new_offset),
335 .fd = new_fd,
336 .timer = ((struct itimerval)
337 { { 0, 1000000 / hz() },
338 { 0, 1000000 / hz() }})});
339 get_safe_registers(regs);
340
341 /* Set parent's instruction pointer to start of clone-stub */
342 regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
343 (unsigned long) stub_clone_handler -
344 (unsigned long) &__syscall_stub_start;
345 regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE -
346 sizeof(void *);
347 err = ptrace_setregs(pid, regs);
348 if(err < 0)
349 panic("copy_context_skas0 : PTRACE_SETREGS failed, "
350 "pid = %d, errno = %d\n", pid, errno);
351
352 /* set a well known return code for detection of child write failure */
353 child_data->err = 12345678;
354
355 /* Wait, until parent has finished its work: read child's pid from
356 * parent's stack, and check, if bad result.
357 */
358 wait_stub_done(pid, 0, "copy_context_skas0");
359
360 pid = data->err;
361 if(pid < 0)
362 panic("copy_context_skas0 - stub-parent reports error %d\n",
363 pid);
364
365 /* Wait, until child has finished too: read child's result from
366 * child's stack and check it.
367 */
368 wait_stub_done(pid, -1, "copy_context_skas0");
369 if (child_data->err != UML_CONFIG_STUB_DATA)
370 panic("copy_context_skas0 - stub-child reports error %d\n",
371 child_data->err);
372
373 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
374 (void *)PTRACE_O_TRACESYSGOOD) < 0)
375 panic("copy_context_skas0 : PTRACE_SETOPTIONS failed, "
376 "errno = %d\n", errno);
377
378 return pid;
379 }
380
381 /*
382 * This is used only, if stub pages are needed, while proc_mm is
383 * availabl. Opening /proc/mm creates a new mm_context, which lacks
384 * the stub-pages. Thus, we map them using /proc/mm-fd
385 */
386 void map_stub_pages(int fd, unsigned long code,
387 unsigned long data, unsigned long stack)
388 {
389 struct proc_mm_op mmop;
390 int n;
391
392 mmop = ((struct proc_mm_op) { .op = MM_MMAP,
393 .u =
394 { .mmap =
395 { .addr = code,
396 .len = PAGE_SIZE,
397 .prot = PROT_EXEC,
398 .flags = MAP_FIXED | MAP_PRIVATE,
399 .fd = stub_code_fd,
400 .offset = stub_code_offset
401 } } });
402 n = os_write_file(fd, &mmop, sizeof(mmop));
403 if(n != sizeof(mmop))
404 panic("map_stub_pages : /proc/mm map for code failed, "
405 "err = %d\n", -n);
406
407 if ( stack ) {
408 __u64 map_offset;
409 int map_fd = phys_mapping(to_phys((void *)stack), &map_offset);
410 mmop = ((struct proc_mm_op)
411 { .op = MM_MMAP,
412 .u =
413 { .mmap =
414 { .addr = data,
415 .len = PAGE_SIZE,
416 .prot = PROT_READ | PROT_WRITE,
417 .flags = MAP_FIXED | MAP_SHARED,
418 .fd = map_fd,
419 .offset = map_offset
420 } } });
421 n = os_write_file(fd, &mmop, sizeof(mmop));
422 if(n != sizeof(mmop))
423 panic("map_stub_pages : /proc/mm map for data failed, "
424 "err = %d\n", -n);
425 }
426 }
427
428 void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr,
429 void (*handler)(int))
430 {
431 unsigned long flags;
432 sigjmp_buf switch_buf, fork_buf;
433
434 *switch_buf_ptr = &switch_buf;
435 *fork_buf_ptr = &fork_buf;
436
437 /* Somewhat subtle - siglongjmp restores the signal mask before doing
438 * the longjmp. This means that when jumping from one stack to another
439 * when the target stack has interrupts enabled, an interrupt may occur
440 * on the source stack. This is bad when starting up a process because
441 * it's not supposed to get timer ticks until it has been scheduled.
442 * So, we disable interrupts around the sigsetjmp to ensure that
443 * they can't happen until we get back here where they are safe.
444 */
445 flags = get_signals();
446 block_signals();
447 if(sigsetjmp(fork_buf, 1) == 0)
448 new_thread_proc(stack, handler);
449
450 remove_sigstack();
451
452 set_signals(flags);
453 }
454
455 void thread_wait(void *sw, void *fb)
456 {
457 sigjmp_buf buf, **switch_buf = sw, *fork_buf;
458
459 *switch_buf = &buf;
460 fork_buf = fb;
461 if(sigsetjmp(buf, 1) == 0)
462 siglongjmp(*fork_buf, INIT_JMP_REMOVE_SIGSTACK);
463 }
464
465 void switch_threads(void *me, void *next)
466 {
467 sigjmp_buf my_buf, **me_ptr = me, *next_buf = next;
468
469 *me_ptr = &my_buf;
470 if(sigsetjmp(my_buf, 1) == 0)
471 siglongjmp(*next_buf, 1);
472 }
473
474 static sigjmp_buf initial_jmpbuf;
475
476 /* XXX Make these percpu */
477 static void (*cb_proc)(void *arg);
478 static void *cb_arg;
479 static sigjmp_buf *cb_back;
480
481 int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr)
482 {
483 sigjmp_buf **switch_buf = switch_buf_ptr;
484 int n;
485
486 set_handler(SIGWINCH, (__sighandler_t) sig_handler,
487 SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM,
488 SIGVTALRM, -1);
489
490 *fork_buf_ptr = &initial_jmpbuf;
491 n = sigsetjmp(initial_jmpbuf, 1);
492 switch(n){
493 case INIT_JMP_NEW_THREAD:
494 new_thread_proc((void *) stack, new_thread_handler);
495 break;
496 case INIT_JMP_REMOVE_SIGSTACK:
497 remove_sigstack();
498 break;
499 case INIT_JMP_CALLBACK:
500 (*cb_proc)(cb_arg);
501 siglongjmp(*cb_back, 1);
502 break;
503 case INIT_JMP_HALT:
504 kmalloc_ok = 0;
505 return(0);
506 case INIT_JMP_REBOOT:
507 kmalloc_ok = 0;
508 return(1);
509 default:
510 panic("Bad sigsetjmp return in start_idle_thread - %d\n", n);
511 }
512 siglongjmp(**switch_buf, 1);
513 }
514
515 void initial_thread_cb_skas(void (*proc)(void *), void *arg)
516 {
517 sigjmp_buf here;
518
519 cb_proc = proc;
520 cb_arg = arg;
521 cb_back = &here;
522
523 block_signals();
524 if(sigsetjmp(here, 1) == 0)
525 siglongjmp(initial_jmpbuf, INIT_JMP_CALLBACK);
526 unblock_signals();
527
528 cb_proc = NULL;
529 cb_arg = NULL;
530 cb_back = NULL;
531 }
532
533 void halt_skas(void)
534 {
535 block_signals();
536 siglongjmp(initial_jmpbuf, INIT_JMP_HALT);
537 }
538
539 void reboot_skas(void)
540 {
541 block_signals();
542 siglongjmp(initial_jmpbuf, INIT_JMP_REBOOT);
543 }
544
545 void switch_mm_skas(struct mm_id *mm_idp)
546 {
547 int err;
548
549 #warning need cpu pid in switch_mm_skas
550 if(proc_mm){
551 err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0,
552 mm_idp->u.mm_fd);
553 if(err)
554 panic("switch_mm_skas - PTRACE_SWITCH_MM failed, "
555 "errno = %d\n", errno);
556 }
557 else userspace_pid[0] = mm_idp->u.pid;
558 }
559
560 /*
561 * Overrides for Emacs so that we follow Linus's tabbing style.
562 * Emacs will notice this stuff at the end of the file and automatically
563 * adjust the settings for this buffer only. This must remain at the end
564 * of the file.
565 * ---------------------------------------------------------------------------
566 * Local variables:
567 * c-file-style: "linux"
568 * End:
569 */
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