Merge branch 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied...
[linux-2.6] / arch / um / os-Linux / skas / process.c
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 "ptrace_user.h"
14 #include <sys/wait.h>
15 #include <sys/mman.h>
16 #include <sys/user.h>
17 #include <sys/time.h>
18 #include <asm/unistd.h>
19 #include <asm/types.h>
20 #include "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 #include "longjmp.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 void wait_stub_done(int pid, int sig, char * fname)
49 {
50         int n, status, err;
51
52         do {
53                 if ( sig != -1 ) {
54                         err = ptrace(PTRACE_CONT, pid, 0, sig);
55                         if(err)
56                                 panic("%s : continue failed, errno = %d\n",
57                                       fname, errno);
58                 }
59                 sig = 0;
60
61                 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
62         } while((n >= 0) && WIFSTOPPED(status) &&
63                 ((WSTOPSIG(status) == SIGVTALRM) ||
64                  /* running UML inside a detached screen can cause
65                   * SIGWINCHes
66                   */
67                  (WSTOPSIG(status) == SIGWINCH)));
68
69         if((n < 0) || !WIFSTOPPED(status) ||
70            (WSTOPSIG(status) != SIGUSR1 && WSTOPSIG(status) != SIGTRAP)){
71                 unsigned long regs[HOST_FRAME_SIZE];
72
73                 if(ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
74                         printk("Failed to get registers from stub, "
75                                "errno = %d\n", errno);
76                 else {
77                         int i;
78
79                         printk("Stub registers -\n");
80                         for(i = 0; i < HOST_FRAME_SIZE; i++)
81                                 printk("\t%d - %lx\n", i, regs[i]);
82                 }
83                 panic("%s : failed to wait for SIGUSR1/SIGTRAP, "
84                       "pid = %d, n = %d, errno = %d, status = 0x%x\n",
85                       fname, pid, n, errno, status);
86         }
87 }
88
89 extern unsigned long current_stub_stack(void);
90
91 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                         panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, "
99                               "errno = %d\n", errno);
100
101                 /* Special handling for i386, which has different structs */
102                 if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo))
103                         memset((char *)fi + sizeof(struct ptrace_faultinfo), 0,
104                                sizeof(struct faultinfo) -
105                                sizeof(struct ptrace_faultinfo));
106         }
107         else {
108                 wait_stub_done(pid, SIGSEGV, "get_skas_faultinfo");
109
110                 /* faultinfo is prepared by the stub-segv-handler at start of
111                  * the stub stack page. We just have to copy it.
112                  */
113                 memcpy(fi, (void *)current_stub_stack(), sizeof(*fi));
114         }
115 }
116
117 static void handle_segv(int pid, union uml_pt_regs * regs)
118 {
119         get_skas_faultinfo(pid, &regs->skas.faultinfo);
120         segv(regs->skas.faultinfo, 0, 1, NULL);
121 }
122
123 /*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/
124 static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu)
125 {
126         int err, status;
127
128         /* Mark this as a syscall */
129         UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->skas.regs);
130
131         if (!local_using_sysemu)
132         {
133                 err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
134                              __NR_getpid);
135                 if(err < 0)
136                         panic("handle_trap - nullifying syscall failed errno = %d\n",
137                               errno);
138
139                 err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
140                 if(err < 0)
141                         panic("handle_trap - continuing to end of syscall failed, "
142                               "errno = %d\n", errno);
143
144                 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
145                 if((err < 0) || !WIFSTOPPED(status) ||
146                    (WSTOPSIG(status) != SIGTRAP + 0x80))
147                         panic("handle_trap - failed to wait at end of syscall, "
148                               "errno = %d, status = %d\n", errno, status);
149         }
150
151         handle_syscall(regs);
152 }
153
154 extern int __syscall_stub_start;
155
156 static int userspace_tramp(void *stack)
157 {
158         void *addr;
159
160         ptrace(PTRACE_TRACEME, 0, 0, 0);
161
162         init_new_thread_signals(1);
163         enable_timer();
164
165         if(!proc_mm){
166                 /* This has a pte, but it can't be mapped in with the usual
167                  * tlb_flush mechanism because this is part of that mechanism
168                  */
169                 int fd;
170                 __u64 offset;
171                 fd = phys_mapping(to_phys(&__syscall_stub_start), &offset);
172                 addr = mmap64((void *) UML_CONFIG_STUB_CODE, page_size(),
173                               PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
174                 if(addr == MAP_FAILED){
175                         printk("mapping mmap stub failed, errno = %d\n",
176                                errno);
177                         exit(1);
178                 }
179
180                 if(stack != NULL){
181                         fd = phys_mapping(to_phys(stack), &offset);
182                         addr = mmap((void *) UML_CONFIG_STUB_DATA, page_size(),
183                                     PROT_READ | PROT_WRITE,
184                                     MAP_FIXED | MAP_SHARED, fd, offset);
185                         if(addr == MAP_FAILED){
186                                 printk("mapping segfault stack failed, "
187                                        "errno = %d\n", errno);
188                                 exit(1);
189                         }
190                 }
191         }
192         if(!ptrace_faultinfo && (stack != NULL)){
193                 unsigned long v = UML_CONFIG_STUB_CODE +
194                                   (unsigned long) stub_segv_handler -
195                                   (unsigned long) &__syscall_stub_start;
196
197                 set_sigstack((void *) UML_CONFIG_STUB_DATA, page_size());
198                 set_handler(SIGSEGV, (void *) v, SA_ONSTACK,
199                             SIGIO, SIGWINCH, SIGALRM, SIGVTALRM,
200                             SIGUSR1, -1);
201         }
202
203         os_stop_process(os_getpid());
204         return(0);
205 }
206
207 /* Each element set once, and only accessed by a single processor anyway */
208 #undef NR_CPUS
209 #define NR_CPUS 1
210 int userspace_pid[NR_CPUS];
211
212 int start_userspace(unsigned long stub_stack)
213 {
214         void *stack;
215         unsigned long sp;
216         int pid, status, n, flags;
217
218         stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC,
219                      MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
220         if(stack == MAP_FAILED)
221                 panic("start_userspace : mmap failed, errno = %d", errno);
222         sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *);
223
224         flags = CLONE_FILES | SIGCHLD;
225         if(proc_mm) flags |= CLONE_VM;
226         pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
227         if(pid < 0)
228                 panic("start_userspace : clone failed, errno = %d", errno);
229
230         do {
231                 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
232                 if(n < 0)
233                         panic("start_userspace : wait failed, errno = %d",
234                               errno);
235         } while(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM));
236
237         if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
238                 panic("start_userspace : expected SIGSTOP, got status = %d",
239                       status);
240
241         if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, (void *)PTRACE_O_TRACESYSGOOD) < 0)
242                 panic("start_userspace : PTRACE_OLDSETOPTIONS failed, errno=%d\n",
243                       errno);
244
245         if(munmap(stack, PAGE_SIZE) < 0)
246                 panic("start_userspace : munmap failed, errno = %d\n", errno);
247
248         return(pid);
249 }
250
251 void userspace(union uml_pt_regs *regs)
252 {
253         int err, status, op, pid = userspace_pid[0];
254         int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/
255
256         while(1){
257                 restore_registers(pid, regs);
258
259                 /* Now we set local_using_sysemu to be used for one loop */
260                 local_using_sysemu = get_using_sysemu();
261
262                 op = SELECT_PTRACE_OPERATION(local_using_sysemu, singlestepping(NULL));
263
264                 err = ptrace(op, pid, 0, 0);
265                 if(err)
266                         panic("userspace - could not resume userspace process, "
267                               "pid=%d, ptrace operation = %d, errno = %d\n",
268                               op, errno);
269
270                 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
271                 if(err < 0)
272                         panic("userspace - waitpid failed, errno = %d\n",
273                               errno);
274
275                 regs->skas.is_user = 1;
276                 save_registers(pid, regs);
277                 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
278
279                 if(WIFSTOPPED(status)){
280                         switch(WSTOPSIG(status)){
281                         case SIGSEGV:
282                                 if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo)
283                                         user_signal(SIGSEGV, regs, pid);
284                                 else handle_segv(pid, regs);
285                                 break;
286                         case SIGTRAP + 0x80:
287                                 handle_trap(pid, regs, local_using_sysemu);
288                                 break;
289                         case SIGTRAP:
290                                 relay_signal(SIGTRAP, regs);
291                                 break;
292                         case SIGIO:
293                         case SIGVTALRM:
294                         case SIGILL:
295                         case SIGBUS:
296                         case SIGFPE:
297                         case SIGWINCH:
298                                 user_signal(WSTOPSIG(status), regs, pid);
299                                 break;
300                         default:
301                                 printk("userspace - child stopped with signal "
302                                        "%d\n", WSTOPSIG(status));
303                         }
304                         pid = userspace_pid[0];
305                         interrupt_end();
306
307                         /* Avoid -ERESTARTSYS handling in host */
308                         if(PT_SYSCALL_NR_OFFSET != PT_SYSCALL_RET_OFFSET)
309                                 PT_SYSCALL_NR(regs->skas.regs) = -1;
310                 }
311         }
312 }
313 #define INIT_JMP_NEW_THREAD 0
314 #define INIT_JMP_REMOVE_SIGSTACK 1
315 #define INIT_JMP_CALLBACK 2
316 #define INIT_JMP_HALT 3
317 #define INIT_JMP_REBOOT 4
318
319 int copy_context_skas0(unsigned long new_stack, int pid)
320 {
321         int err;
322         unsigned long regs[MAX_REG_NR];
323         unsigned long current_stack = current_stub_stack();
324         struct stub_data *data = (struct stub_data *) current_stack;
325         struct stub_data *child_data = (struct stub_data *) new_stack;
326         __u64 new_offset;
327         int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset);
328
329         /* prepare offset and fd of child's stack as argument for parent's
330          * and child's mmap2 calls
331          */
332         *data = ((struct stub_data) { .offset   = MMAP_OFFSET(new_offset),
333                                       .fd       = new_fd,
334                                       .timer    = ((struct itimerval)
335                                                     { { 0, 1000000 / hz() },
336                                                       { 0, 1000000 / hz() }})});
337         get_safe_registers(regs);
338
339         /* Set parent's instruction pointer to start of clone-stub */
340         regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
341                                 (unsigned long) stub_clone_handler -
342                                 (unsigned long) &__syscall_stub_start;
343         regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE -
344                 sizeof(void *);
345 #ifdef __SIGNAL_FRAMESIZE
346         regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
347 #endif
348         err = ptrace_setregs(pid, regs);
349         if(err < 0)
350                 panic("copy_context_skas0 : PTRACE_SETREGS failed, "
351                       "pid = %d, errno = %d\n", pid, errno);
352
353         /* set a well known return code for detection of child write failure */
354         child_data->err = 12345678;
355
356         /* Wait, until parent has finished its work: read child's pid from
357          * parent's stack, and check, if bad result.
358          */
359         wait_stub_done(pid, 0, "copy_context_skas0");
360
361         pid = data->err;
362         if(pid < 0)
363                 panic("copy_context_skas0 - stub-parent reports error %d\n",
364                       pid);
365
366         /* Wait, until child has finished too: read child's result from
367          * child's stack and check it.
368          */
369         wait_stub_done(pid, -1, "copy_context_skas0");
370         if (child_data->err != UML_CONFIG_STUB_DATA)
371                 panic("copy_context_skas0 - stub-child reports error %d\n",
372                       child_data->err);
373
374         if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
375                    (void *)PTRACE_O_TRACESYSGOOD) < 0)
376                 panic("copy_context_skas0 : PTRACE_OLDSETOPTIONS failed, "
377                       "errno = %d\n", errno);
378
379         return pid;
380 }
381
382 /*
383  * This is used only, if stub pages are needed, while proc_mm is
384  * availabl. Opening /proc/mm creates a new mm_context, which lacks
385  * the stub-pages. Thus, we map them using /proc/mm-fd
386  */
387 void map_stub_pages(int fd, unsigned long code,
388                     unsigned long data, unsigned long stack)
389 {
390         struct proc_mm_op mmop;
391         int n;
392         __u64 code_offset;
393         int code_fd = phys_mapping(to_phys((void *) &__syscall_stub_start),
394                                    &code_offset);
395
396         mmop = ((struct proc_mm_op) { .op        = MM_MMAP,
397                                       .u         =
398                                       { .mmap    =
399                                         { .addr    = code,
400                                           .len     = PAGE_SIZE,
401                                           .prot    = PROT_EXEC,
402                                           .flags   = MAP_FIXED | MAP_PRIVATE,
403                                           .fd      = code_fd,
404                                           .offset  = code_offset
405         } } });
406         n = os_write_file(fd, &mmop, sizeof(mmop));
407         if(n != sizeof(mmop))
408                 panic("map_stub_pages : /proc/mm map for code failed, "
409                       "err = %d\n", -n);
410
411         if ( stack ) {
412                 __u64 map_offset;
413                 int map_fd = phys_mapping(to_phys((void *)stack), &map_offset);
414                 mmop = ((struct proc_mm_op)
415                                 { .op        = MM_MMAP,
416                                   .u         =
417                                   { .mmap    =
418                                     { .addr    = data,
419                                       .len     = PAGE_SIZE,
420                                       .prot    = PROT_READ | PROT_WRITE,
421                                       .flags   = MAP_FIXED | MAP_SHARED,
422                                       .fd      = map_fd,
423                                       .offset  = map_offset
424                 } } });
425                 n = os_write_file(fd, &mmop, sizeof(mmop));
426                 if(n != sizeof(mmop))
427                         panic("map_stub_pages : /proc/mm map for data failed, "
428                               "err = %d\n", -n);
429         }
430 }
431
432 void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr,
433                 void (*handler)(int))
434 {
435         unsigned long flags;
436         sigjmp_buf switch_buf, fork_buf;
437         int enable;
438
439         *switch_buf_ptr = &switch_buf;
440         *fork_buf_ptr = &fork_buf;
441
442         /* Somewhat subtle - siglongjmp restores the signal mask before doing
443          * the longjmp.  This means that when jumping from one stack to another
444          * when the target stack has interrupts enabled, an interrupt may occur
445          * on the source stack.  This is bad when starting up a process because
446          * it's not supposed to get timer ticks until it has been scheduled.
447          * So, we disable interrupts around the sigsetjmp to ensure that
448          * they can't happen until we get back here where they are safe.
449          */
450         flags = get_signals();
451         block_signals();
452         if(UML_SIGSETJMP(&fork_buf, enable) == 0)
453                 new_thread_proc(stack, handler);
454
455         remove_sigstack();
456
457         set_signals(flags);
458 }
459
460 void thread_wait(void *sw, void *fb)
461 {
462         sigjmp_buf buf, **switch_buf = sw, *fork_buf;
463         int enable;
464
465         *switch_buf = &buf;
466         fork_buf = fb;
467         if(UML_SIGSETJMP(&buf, enable) == 0)
468                 siglongjmp(*fork_buf, INIT_JMP_REMOVE_SIGSTACK);
469 }
470
471 void switch_threads(void *me, void *next)
472 {
473         sigjmp_buf my_buf, **me_ptr = me, *next_buf = next;
474         int enable;
475
476         *me_ptr = &my_buf;
477         if(UML_SIGSETJMP(&my_buf, enable) == 0)
478                 UML_SIGLONGJMP(next_buf, 1);
479 }
480
481 static sigjmp_buf initial_jmpbuf;
482
483 /* XXX Make these percpu */
484 static void (*cb_proc)(void *arg);
485 static void *cb_arg;
486 static sigjmp_buf *cb_back;
487
488 int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr)
489 {
490         sigjmp_buf **switch_buf = switch_buf_ptr;
491         int n, enable;
492
493         set_handler(SIGWINCH, (__sighandler_t) sig_handler,
494                     SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM,
495                     SIGVTALRM, -1);
496
497         *fork_buf_ptr = &initial_jmpbuf;
498         n = UML_SIGSETJMP(&initial_jmpbuf, enable);
499         switch(n){
500         case INIT_JMP_NEW_THREAD:
501                 new_thread_proc((void *) stack, new_thread_handler);
502                 break;
503         case INIT_JMP_REMOVE_SIGSTACK:
504                 remove_sigstack();
505                 break;
506         case INIT_JMP_CALLBACK:
507                 (*cb_proc)(cb_arg);
508                 UML_SIGLONGJMP(cb_back, 1);
509                 break;
510         case INIT_JMP_HALT:
511                 kmalloc_ok = 0;
512                 return(0);
513         case INIT_JMP_REBOOT:
514                 kmalloc_ok = 0;
515                 return(1);
516         default:
517                 panic("Bad sigsetjmp return in start_idle_thread - %d\n", n);
518         }
519         UML_SIGLONGJMP(*switch_buf, 1);
520 }
521
522 void initial_thread_cb_skas(void (*proc)(void *), void *arg)
523 {
524         sigjmp_buf here;
525         int enable;
526
527         cb_proc = proc;
528         cb_arg = arg;
529         cb_back = &here;
530
531         block_signals();
532         if(UML_SIGSETJMP(&here, enable) == 0)
533                 UML_SIGLONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK);
534         unblock_signals();
535
536         cb_proc = NULL;
537         cb_arg = NULL;
538         cb_back = NULL;
539 }
540
541 void halt_skas(void)
542 {
543         block_signals();
544         UML_SIGLONGJMP(&initial_jmpbuf, INIT_JMP_HALT);
545 }
546
547 void reboot_skas(void)
548 {
549         block_signals();
550         UML_SIGLONGJMP(&initial_jmpbuf, INIT_JMP_REBOOT);
551 }
552
553 void switch_mm_skas(struct mm_id *mm_idp)
554 {
555         int err;
556
557 #warning need cpu pid in switch_mm_skas
558         if(proc_mm){
559                 err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0,
560                              mm_idp->u.mm_fd);
561                 if(err)
562                         panic("switch_mm_skas - PTRACE_SWITCH_MM failed, "
563                               "errno = %d\n", errno);
564         }
565         else userspace_pid[0] = mm_idp->u.pid;
566 }