SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 <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
  37 int is_skas_winch(int pid, int fd, void *data)
  38 {
  39         if(pid != os_getpgrp())
  40                 return(0);
  41
  42         register_winch_irq(-1, fd, -1, data);
  43         return(1);
  44 }
  45
  46 void wait_stub_done(int pid, int sig, char * fname)
  47 {
  48         int n, status, err;
  49
  50         do {
  51                 if ( sig != -1 ) {
  52                         err = ptrace(PTRACE_CONT, pid, 0, sig);
  53                         if(err)
  54                                 panic("%s : continue failed, errno = %d\n",
  55                                       fname, errno);
  56                 }
  57                 sig = 0;
  58
  59                 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
  60         } while((n >= 0) && WIFSTOPPED(status) &&
  61                 ((WSTOPSIG(status) == SIGVTALRM) ||
  62                  /* running UML inside a detached screen can cause
  63                   * SIGWINCHes
  64                   */
  65                  (WSTOPSIG(status) == SIGWINCH)));
  66
  67         if((n < 0) || !WIFSTOPPED(status) ||
  68            (WSTOPSIG(status) != SIGUSR1 && WSTOPSIG(status) != SIGTRAP)){
  69                 unsigned long regs[MAX_REG_NR];
  70
  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 < ARRAY_SIZE(regs); 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 extern unsigned long current_stub_stack(void);
  88
  89 void get_skas_faultinfo(int pid, struct faultinfo * fi)
  90 {
  91         int err;
  92
  93         if(ptrace_faultinfo){
  94                 err = ptrace(PTRACE_FAULTINFO, pid, 0, fi);
  95                 if(err)
  96                         panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, "
  97                               "errno = %d\n", errno);
  98
  99                 /* Special handling for i386, which has different structs */
 100                 if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo))
 101                         memset((char *)fi + sizeof(struct ptrace_faultinfo), 0,
 102                                sizeof(struct faultinfo) -
 103                                sizeof(struct ptrace_faultinfo));
 104         }
 105         else {
 106                 wait_stub_done(pid, SIGSEGV, "get_skas_faultinfo");
 107
 108                 /* faultinfo is prepared by the stub-segv-handler at start of
 109                  * the stub stack page. We just have to copy it.
 110                  */
 111                 memcpy(fi, (void *)current_stub_stack(), sizeof(*fi));
 112         }
 113 }
 114
 115 static void handle_segv(int pid, union uml_pt_regs * regs)
 116 {
 117         get_skas_faultinfo(pid, &regs->skas.faultinfo);
 118         segv(regs->skas.faultinfo, 0, 1, NULL);
 119 }
 120
 121 /*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/
 122 static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu)
 123 {
 124         int err, status;
 125
 126         /* Mark this as a syscall */
 127         UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->skas.regs);
 128
 129         if (!local_using_sysemu)
 130         {
 131                 err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
 132                              __NR_getpid);
 133                 if(err < 0)
 134                         panic("handle_trap - nullifying syscall failed errno = %d\n",
 135                               errno);
 136
 137                 err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
 138                 if(err < 0)
 139                         panic("handle_trap - continuing to end of syscall failed, "
 140                               "errno = %d\n", errno);
 141
 142                 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
 143                 if((err < 0) || !WIFSTOPPED(status) ||
 144                    (WSTOPSIG(status) != SIGTRAP + 0x80))
 145                         panic("handle_trap - failed to wait at end of syscall, "
 146                               "errno = %d, status = %d\n", errno, status);
 147         }
 148
 149         handle_syscall(regs);
 150 }
 151
 152 extern int __syscall_stub_start;
 153
 154 static int userspace_tramp(void *stack)
 155 {
 156         void *addr;
 157         int err;
 158
 159         ptrace(PTRACE_TRACEME, 0, 0, 0);
 160
 161         init_new_thread_signals();
 162         err = set_interval(1);
 163         if(err)
 164                 panic("userspace_tramp - setting timer failed, errno = %d\n",
 165                       err);
 166
 167         if(!proc_mm){
 168                 /* This has a pte, but it can't be mapped in with the usual
 169                  * tlb_flush mechanism because this is part of that mechanism
 170                  */
 171                 int fd;
 172                 __u64 offset;
 173                 fd = phys_mapping(to_phys(&__syscall_stub_start), &offset);
 174                 addr = mmap64((void *) UML_CONFIG_STUB_CODE, page_size(),
 175                               PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset);
 176                 if(addr == MAP_FAILED){
 177                         printk("mapping mmap stub failed, errno = %d\n",
 178                                errno);
 179                         exit(1);
 180                 }
 181
 182                 if(stack != NULL){
 183                         fd = phys_mapping(to_phys(stack), &offset);
 184                         addr = mmap((void *) UML_CONFIG_STUB_DATA, page_size(),
 185                                     PROT_READ | PROT_WRITE,
 186                                     MAP_FIXED | MAP_SHARED, fd, offset);
 187                         if(addr == MAP_FAILED){
 188                                 printk("mapping segfault stack failed, "
 189                                        "errno = %d\n", errno);
 190                                 exit(1);
 191                         }
 192                 }
 193         }
 194         if(!ptrace_faultinfo && (stack != NULL)){
 195                 struct sigaction sa;
 196
 197                 unsigned long v = UML_CONFIG_STUB_CODE +
 198                                   (unsigned long) stub_segv_handler -
 199                                   (unsigned long) &__syscall_stub_start;
 200
 201                 set_sigstack((void *) UML_CONFIG_STUB_DATA, page_size());
 202                 sigemptyset(&sa.sa_mask);
 203                 sigaddset(&sa.sa_mask, SIGIO);
 204                 sigaddset(&sa.sa_mask, SIGWINCH);
 205                 sigaddset(&sa.sa_mask, SIGALRM);
 206                 sigaddset(&sa.sa_mask, SIGVTALRM);
 207                 sigaddset(&sa.sa_mask, SIGUSR1);
 208                 sa.sa_flags = SA_ONSTACK;
 209                 sa.sa_handler = (void *) v;
 210                 sa.sa_restorer = NULL;
 211                 if(sigaction(SIGSEGV, &sa, NULL) < 0)
 212                         panic("userspace_tramp - setting SIGSEGV handler "
 213                               "failed - errno = %d\n", errno);
 214         }
 215
 216         os_stop_process(os_getpid());
 217         return(0);
 218 }
 219
 220 /* Each element set once, and only accessed by a single processor anyway */
 221 #undef NR_CPUS
 222 #define NR_CPUS 1
 223 int userspace_pid[NR_CPUS];
 224
 225 int start_userspace(unsigned long stub_stack)
 226 {
 227         void *stack;
 228         unsigned long sp;
 229         int pid, status, n, flags;
 230
 231         stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC,
 232                      MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 233         if(stack == MAP_FAILED)
 234                 panic("start_userspace : mmap failed, errno = %d", errno);
 235         sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *);
 236
 237         flags = CLONE_FILES | SIGCHLD;
 238         if(proc_mm) flags |= CLONE_VM;
 239         pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
 240         if(pid < 0)
 241                 panic("start_userspace : clone failed, errno = %d", errno);
 242
 243         do {
 244                 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
 245                 if(n < 0)
 246                         panic("start_userspace : wait failed, errno = %d",
 247                               errno);
 248         } while(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM));
 249
 250         if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
 251                 panic("start_userspace : expected SIGSTOP, got status = %d",
 252                       status);
 253
 254         if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, (void *)PTRACE_O_TRACESYSGOOD) < 0)
 255                 panic("start_userspace : PTRACE_OLDSETOPTIONS failed, errno=%d\n",
 256                       errno);
 257
 258         if(munmap(stack, PAGE_SIZE) < 0)
 259                 panic("start_userspace : munmap failed, errno = %d\n", errno);
 260
 261         return(pid);
 262 }
 263
 264 void userspace(union uml_pt_regs *regs)
 265 {
 266         int err, status, op, pid = userspace_pid[0];
 267         int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/
 268
 269         while(1){
 270                 restore_registers(pid, regs);
 271
 272                 /* Now we set local_using_sysemu to be used for one loop */
 273                 local_using_sysemu = get_using_sysemu();
 274
 275                 op = SELECT_PTRACE_OPERATION(local_using_sysemu, singlestepping(NULL));
 276
 277                 err = ptrace(op, pid, 0, 0);
 278                 if(err)
 279                         panic("userspace - could not resume userspace process, "
 280                               "pid=%d, ptrace operation = %d, errno = %d\n",
 281                               pid, op, errno);
 282
 283                 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
 284                 if(err < 0)
 285                         panic("userspace - waitpid failed, errno = %d\n",
 286                               errno);
 287
 288                 regs->skas.is_user = 1;
 289                 save_registers(pid, regs);
 290                 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
 291
 292                 if(WIFSTOPPED(status)){
 293                         switch(WSTOPSIG(status)){
 294                         case SIGSEGV:
 295                                 if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo)
 296                                         user_signal(SIGSEGV, regs, pid);
 297                                 else handle_segv(pid, regs);
 298                                 break;
 299                         case SIGTRAP + 0x80:
 300                                 handle_trap(pid, regs, local_using_sysemu);
 301                                 break;
 302                         case SIGTRAP:
 303                                 relay_signal(SIGTRAP, regs);
 304                                 break;
 305                         case SIGIO:
 306                         case SIGVTALRM:
 307                         case SIGILL:
 308                         case SIGBUS:
 309                         case SIGFPE:
 310                         case SIGWINCH:
 311                                 user_signal(WSTOPSIG(status), regs, pid);
 312                                 break;
 313                         default:
 314                                 printk("userspace - child stopped with signal "
 315                                        "%d\n", WSTOPSIG(status));
 316                         }
 317                         pid = userspace_pid[0];
 318                         interrupt_end();
 319
 320                         /* Avoid -ERESTARTSYS handling in host */
 321                         if(PT_SYSCALL_NR_OFFSET != PT_SYSCALL_RET_OFFSET)
 322                                 PT_SYSCALL_NR(regs->skas.regs) = -1;
 323                 }
 324         }
 325 }
 326
 327 int copy_context_skas0(unsigned long new_stack, int pid)
 328 {
 329         int err;
 330         unsigned long regs[MAX_REG_NR];
 331         unsigned long fp_regs[HOST_FP_SIZE];
 332         unsigned long current_stack = current_stub_stack();
 333         struct stub_data *data = (struct stub_data *) current_stack;
 334         struct stub_data *child_data = (struct stub_data *) new_stack;
 335         __u64 new_offset;
 336         int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset);
 337
 338         /* prepare offset and fd of child's stack as argument for parent's
 339          * and child's mmap2 calls
 340          */
 341         *data = ((struct stub_data) { .offset   = MMAP_OFFSET(new_offset),
 342                                       .fd       = new_fd,
 343                                       .timer    = ((struct itimerval)
 344                                                     { { 0, 1000000 / hz() },
 345                                                       { 0, 1000000 / hz() }})});
 346         get_safe_registers(regs, fp_regs);
 347
 348         /* Set parent's instruction pointer to start of clone-stub */
 349         regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
 350                                 (unsigned long) stub_clone_handler -
 351                                 (unsigned long) &__syscall_stub_start;
 352         regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE -
 353                 sizeof(void *);
 354 #ifdef __SIGNAL_FRAMESIZE
 355         regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
 356 #endif
 357         err = ptrace_setregs(pid, regs);
 358         if(err < 0)
 359                 panic("copy_context_skas0 : PTRACE_SETREGS failed, "
 360                       "pid = %d, errno = %d\n", pid, -err);
 361
 362         err = ptrace_setfpregs(pid, fp_regs);
 363         if(err < 0)
 364                 panic("copy_context_skas0 : PTRACE_SETFPREGS failed, "
 365                       "pid = %d, errno = %d\n", pid, -err);
 366
 367         /* set a well known return code for detection of child write failure */
 368         child_data->err = 12345678;
 369
 370         /* Wait, until parent has finished its work: read child's pid from
 371          * parent's stack, and check, if bad result.
 372          */
 373         wait_stub_done(pid, 0, "copy_context_skas0");
 374
 375         pid = data->err;
 376         if(pid < 0)
 377                 panic("copy_context_skas0 - stub-parent reports error %d\n",
 378                       -pid);
 379
 380         /* Wait, until child has finished too: read child's result from
 381          * child's stack and check it.
 382          */
 383         wait_stub_done(pid, -1, "copy_context_skas0");
 384         if (child_data->err != UML_CONFIG_STUB_DATA)
 385                 panic("copy_context_skas0 - stub-child reports error %ld\n",
 386                       child_data->err);
 387
 388         if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
 389                    (void *)PTRACE_O_TRACESYSGOOD) < 0)
 390                 panic("copy_context_skas0 : PTRACE_OLDSETOPTIONS failed, "
 391                       "errno = %d\n", errno);
 392
 393         return pid;
 394 }
 395
 396 /*
 397  * This is used only, if stub pages are needed, while proc_mm is
 398  * availabl. Opening /proc/mm creates a new mm_context, which lacks
 399  * the stub-pages. Thus, we map them using /proc/mm-fd
 400  */
 401 void map_stub_pages(int fd, unsigned long code,
 402                     unsigned long data, unsigned long stack)
 403 {
 404         struct proc_mm_op mmop;
 405         int n;
 406         __u64 code_offset;
 407         int code_fd = phys_mapping(to_phys((void *) &__syscall_stub_start),
 408                                    &code_offset);
 409
 410         mmop = ((struct proc_mm_op) { .op        = MM_MMAP,
 411                                       .u         =
 412                                       { .mmap    =
 413                                         { .addr    = code,
 414                                           .len     = PAGE_SIZE,
 415                                           .prot    = PROT_EXEC,
 416                                           .flags   = MAP_FIXED | MAP_PRIVATE,
 417                                           .fd      = code_fd,
 418                                           .offset  = code_offset
 419         } } });
 420         n = os_write_file(fd, &mmop, sizeof(mmop));
 421         if(n != sizeof(mmop)){
 422                 printk("mmap args - addr = 0x%lx, fd = %d, offset = %llx\n",
 423                        code, code_fd, (unsigned long long) code_offset);
 424                 panic("map_stub_pages : /proc/mm map for code failed, "
 425                       "err = %d\n", -n);
 426         }
 427
 428         if ( stack ) {
 429                 __u64 map_offset;
 430                 int map_fd = phys_mapping(to_phys((void *)stack), &map_offset);
 431                 mmop = ((struct proc_mm_op)
 432                                 { .op        = MM_MMAP,
 433                                   .u         =
 434                                   { .mmap    =
 435                                     { .addr    = data,
 436                                       .len     = PAGE_SIZE,
 437                                       .prot    = PROT_READ | PROT_WRITE,
 438                                       .flags   = MAP_FIXED | MAP_SHARED,
 439                                       .fd      = map_fd,
 440                                       .offset  = map_offset
 441                 } } });
 442                 n = os_write_file(fd, &mmop, sizeof(mmop));
 443                 if(n != sizeof(mmop))
 444                         panic("map_stub_pages : /proc/mm map for data failed, "
 445                               "err = %d\n", -n);
 446         }
 447 }
 448
 449 void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
 450 {
 451         (*buf)[0].JB_IP = (unsigned long) handler;
 452         (*buf)[0].JB_SP = (unsigned long) stack +
 453                 (PAGE_SIZE << UML_CONFIG_KERNEL_STACK_ORDER) - sizeof(void *);
 454 }
 455
 456 #define INIT_JMP_NEW_THREAD 0
 457 #define INIT_JMP_CALLBACK 1
 458 #define INIT_JMP_HALT 2
 459 #define INIT_JMP_REBOOT 3
 460
 461 void switch_threads(jmp_buf *me, jmp_buf *you)
 462 {
 463         if(UML_SETJMP(me) == 0)
 464                 UML_LONGJMP(you, 1);
 465 }
 466
 467 static jmp_buf initial_jmpbuf;
 468
 469 /* XXX Make these percpu */
 470 static void (*cb_proc)(void *arg);
 471 static void *cb_arg;
 472 static jmp_buf *cb_back;
 473
 474 int start_idle_thread(void *stack, jmp_buf *switch_buf)
 475 {
 476         int n;
 477
 478         set_handler(SIGWINCH, (__sighandler_t) sig_handler,
 479                     SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM,
 480                     SIGVTALRM, -1);
 481
 482         n = UML_SETJMP(&initial_jmpbuf);
 483         switch(n){
 484         case INIT_JMP_NEW_THREAD:
 485                 (*switch_buf)[0].JB_IP = (unsigned long) new_thread_handler;
 486                 (*switch_buf)[0].JB_SP = (unsigned long) stack +
 487                         (PAGE_SIZE << UML_CONFIG_KERNEL_STACK_ORDER) -
 488                         sizeof(void *);
 489                 break;
 490         case INIT_JMP_CALLBACK:
 491                 (*cb_proc)(cb_arg);
 492                 UML_LONGJMP(cb_back, 1);
 493                 break;
 494         case INIT_JMP_HALT:
 495                 kmalloc_ok = 0;
 496                 return(0);
 497         case INIT_JMP_REBOOT:
 498                 kmalloc_ok = 0;
 499                 return(1);
 500         default:
 501                 panic("Bad sigsetjmp return in start_idle_thread - %d\n", n);
 502         }
 503         UML_LONGJMP(switch_buf, 1);
 504 }
 505
 506 void initial_thread_cb_skas(void (*proc)(void *), void *arg)
 507 {
 508         jmp_buf here;
 509
 510         cb_proc = proc;
 511         cb_arg = arg;
 512         cb_back = &here;
 513
 514         block_signals();
 515         if(UML_SETJMP(&here) == 0)
 516                 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK);
 517         unblock_signals();
 518
 519         cb_proc = NULL;
 520         cb_arg = NULL;
 521         cb_back = NULL;
 522 }
 523
 524 void halt_skas(void)
 525 {
 526         block_signals();
 527         UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT);
 528 }
 529
 530 void reboot_skas(void)
 531 {
 532         block_signals();
 533         UML_LONGJMP(&initial_jmpbuf, INIT_JMP_REBOOT);
 534 }
 535
 536 void switch_mm_skas(struct mm_id *mm_idp)
 537 {
 538         int err;
 539
 540 #warning need cpu pid in switch_mm_skas
 541         if(proc_mm){
 542                 err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0,
 543                              mm_idp->u.mm_fd);
 544                 if(err)
 545                         panic("switch_mm_skas - PTRACE_SWITCH_MM failed, "
 546                               "errno = %d\n", errno);
 547         }
 548         else userspace_pid[0] = mm_idp->u.pid;
 549 }