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 "time_user.h" 22 #include "sysdep/ptrace.h" 23 #include "user_util.h" 24 #include "kern_util.h" 25 #include "skas.h" 26 #include "stub-data.h" 27 #include "mm_id.h" 28 #include "sysdep/sigcontext.h" 29 #include "sysdep/stub.h" 30 #include "os.h" 31 #include "proc_mm.h" 32 #include "skas_ptrace.h" 33 #include "chan_user.h" 34 #include "signal_user.h" 35 #include "registers.h" 36 #include "mem.h" 37 #include "uml-config.h" 38 #include "process.h" 39 40 int is_skas_winch(int pid, int fd, void *data) 41 { 42 if(pid != os_getpgrp()) 43 return(0); 44 45 register_winch_irq(-1, fd, -1, data); 46 return(1); 47 } 48 49 void wait_stub_done(int pid, int sig, char * fname) 50 { 51 int n, status, err; 52 53 do { 54 if ( sig != -1 ) { 55 err = ptrace(PTRACE_CONT, pid, 0, sig); 56 if(err) 57 panic("%s : continue failed, errno = %d\n", 58 fname, errno); 59 } 60 sig = 0; 61 62 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); 63 } while((n >= 0) && WIFSTOPPED(status) && 64 ((WSTOPSIG(status) == SIGVTALRM) || 65 /* running UML inside a detached screen can cause 66 * SIGWINCHes 67 */ 68 (WSTOPSIG(status) == SIGWINCH))); 69 70 if((n < 0) || !WIFSTOPPED(status) || 71 (WSTOPSIG(status) != SIGUSR1 && WSTOPSIG(status) != SIGTRAP)){ 72 panic("%s : failed to wait for SIGUSR1/SIGTRAP, " 73 "pid = %d, n = %d, errno = %d, status = 0x%x\n", 74 fname, pid, n, errno, status); 75 } 76 } 77 78 void get_skas_faultinfo(int pid, struct faultinfo * fi) 79 { 80 int err; 81 82 if(ptrace_faultinfo){ 83 err = ptrace(PTRACE_FAULTINFO, pid, 0, fi); 84 if(err) 85 panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, " 86 "errno = %d\n", errno); 87 88 /* Special handling for i386, which has different structs */ 89 if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo)) 90 memset((char *)fi + sizeof(struct ptrace_faultinfo), 0, 91 sizeof(struct faultinfo) - 92 sizeof(struct ptrace_faultinfo)); 93 } 94 else { 95 wait_stub_done(pid, SIGSEGV, "get_skas_faultinfo"); 96 97 /* faultinfo is prepared by the stub-segv-handler at start of 98 * the stub stack page. We just have to copy it. 99 */ 100 memcpy(fi, (void *)current_stub_stack(), sizeof(*fi)); 101 } 102 } 103 104 static void handle_segv(int pid, union uml_pt_regs * regs) 105 { 106 get_skas_faultinfo(pid, ®s->skas.faultinfo); 107 segv(regs->skas.faultinfo, 0, 1, NULL); 108 } 109 110 /*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/ 111 static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu) 112 { 113 int err, status; 114 115 /* Mark this as a syscall */ 116 UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->skas.regs); 117 118 if (!local_using_sysemu) 119 { 120 err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET, __NR_getpid); 121 if(err < 0) 122 panic("handle_trap - nullifying syscall failed errno = %d\n", 123 errno); 124 125 err = ptrace(PTRACE_SYSCALL, pid, 0, 0); 126 if(err < 0) 127 panic("handle_trap - continuing to end of syscall failed, " 128 "errno = %d\n", errno); 129 130 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED)); 131 if((err < 0) || !WIFSTOPPED(status) || 132 (WSTOPSIG(status) != SIGTRAP + 0x80)) 133 panic("handle_trap - failed to wait at end of syscall, " 134 "errno = %d, status = %d\n", errno, status); 135 } 136 137 handle_syscall(regs); 138 } 139 140 extern int __syscall_stub_start; 141 int stub_code_fd = -1; 142 __u64 stub_code_offset; 143 144 static int userspace_tramp(void *stack) 145 { 146 void *addr; 147 148 ptrace(PTRACE_TRACEME, 0, 0, 0); 149 150 init_new_thread_signals(1); 151 enable_timer(); 152 153 if(!proc_mm){ 154 /* This has a pte, but it can't be mapped in with the usual 155 * tlb_flush mechanism because this is part of that mechanism 156 */ 157 addr = mmap64((void *) UML_CONFIG_STUB_CODE, page_size(), 158 PROT_EXEC, MAP_FIXED | MAP_PRIVATE, 159 stub_code_fd, stub_code_offset); 160 if(addr == MAP_FAILED){ 161 printk("mapping stub code failed, errno = %d\n", 162 errno); 163 exit(1); 164 } 165 166 if(stack != NULL){ 167 int fd; 168 __u64 offset; 169 170 fd = phys_mapping(to_phys(stack), &offset); 171 addr = mmap((void *) UML_CONFIG_STUB_DATA, page_size(), 172 PROT_READ | PROT_WRITE, 173 MAP_FIXED | MAP_SHARED, fd, offset); 174 if(addr == MAP_FAILED){ 175 printk("mapping stub stack failed, " 176 "errno = %d\n", errno); 177 exit(1); 178 } 179 } 180 } 181 if(!ptrace_faultinfo){ 182 unsigned long v = UML_CONFIG_STUB_CODE + 183 (unsigned long) stub_segv_handler - 184 (unsigned long) &__syscall_stub_start; 185 186 set_sigstack((void *) UML_CONFIG_STUB_DATA, page_size()); 187 set_handler(SIGSEGV, (void *) v, SA_ONSTACK, 188 SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, 189 SIGUSR1, -1); 190 } 191 192 os_stop_process(os_getpid()); 193 return(0); 194 } 195 196 /* Each element set once, and only accessed by a single processor anyway */ 197 #undef NR_CPUS 198 #define NR_CPUS 1 199 int userspace_pid[NR_CPUS]; 200 201 int start_userspace(unsigned long stub_stack) 202 { 203 void *stack; 204 unsigned long sp; 205 int pid, status, n, flags; 206 207 if ( stub_code_fd == -1 ) 208 stub_code_fd = phys_mapping(to_phys(&__syscall_stub_start), 209 &stub_code_offset); 210 211 stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC, 212 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); 213 if(stack == MAP_FAILED) 214 panic("start_userspace : mmap failed, errno = %d", errno); 215 sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *); 216 217 flags = CLONE_FILES | SIGCHLD; 218 if(proc_mm) flags |= CLONE_VM; 219 pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack); 220 if(pid < 0) 221 panic("start_userspace : clone failed, errno = %d", errno); 222 223 do { 224 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); 225 if(n < 0) 226 panic("start_userspace : wait failed, errno = %d", 227 errno); 228 } while(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM)); 229 230 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) 231 panic("start_userspace : expected SIGSTOP, got status = %d", 232 status); 233 234 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, (void *)PTRACE_O_TRACESYSGOOD) < 0) 235 panic("start_userspace : PTRACE_SETOPTIONS failed, errno=%d\n", 236 errno); 237 238 if(munmap(stack, PAGE_SIZE) < 0) 239 panic("start_userspace : munmap failed, errno = %d\n", errno); 240 241 return(pid); 242 } 243 244 void userspace(union uml_pt_regs *regs) 245 { 246 int err, status, op, pid = userspace_pid[0]; 247 int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/ 248 249 while(1){ 250 restore_registers(pid, regs); 251 252 /* Now we set local_using_sysemu to be used for one loop */ 253 local_using_sysemu = get_using_sysemu(); 254 255 op = SELECT_PTRACE_OPERATION(local_using_sysemu, singlestepping(NULL)); 256 257 err = ptrace(op, pid, 0, 0); 258 if(err) 259 panic("userspace - could not resume userspace process, " 260 "pid=%d, ptrace operation = %d, errno = %d\n", 261 op, errno); 262 263 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED)); 264 if(err < 0) 265 panic("userspace - waitpid failed, errno = %d\n", 266 errno); 267 268 regs->skas.is_user = 1; 269 save_registers(pid, regs); 270 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */ 271 272 if(WIFSTOPPED(status)){ 273 switch(WSTOPSIG(status)){ 274 case SIGSEGV: 275 if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo) 276 user_signal(SIGSEGV, regs, pid); 277 else handle_segv(pid, regs); 278 break; 279 case SIGTRAP + 0x80: 280 handle_trap(pid, regs, local_using_sysemu); 281 break; 282 case SIGTRAP: 283 relay_signal(SIGTRAP, regs); 284 break; 285 case SIGIO: 286 case SIGVTALRM: 287 case SIGILL: 288 case SIGBUS: 289 case SIGFPE: 290 case SIGWINCH: 291 user_signal(WSTOPSIG(status), regs, pid); 292 break; 293 default: 294 printk("userspace - child stopped with signal " 295 "%d\n", WSTOPSIG(status)); 296 } 297 pid = userspace_pid[0]; 298 interrupt_end(); 299 300 /* Avoid -ERESTARTSYS handling in host */ 301 PT_SYSCALL_NR(regs->skas.regs) = -1; 302 } 303 } 304 } 305 #define INIT_JMP_NEW_THREAD 0 306 #define INIT_JMP_REMOVE_SIGSTACK 1 307 #define INIT_JMP_CALLBACK 2 308 #define INIT_JMP_HALT 3 309 #define INIT_JMP_REBOOT 4 310 311 312 int copy_context_skas0(unsigned long new_stack, int pid) 313 { 314 int err; 315 unsigned long regs[MAX_REG_NR]; 316 unsigned long current_stack = current_stub_stack(); 317 struct stub_data *data = (struct stub_data *) current_stack; 318 struct stub_data *child_data = (struct stub_data *) new_stack; 319 __u64 new_offset; 320 int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset); 321 322 /* prepare offset and fd of child's stack as argument for parent's 323 * and child's mmap2 calls 324 */ 325 *data = ((struct stub_data) { .offset = MMAP_OFFSET(new_offset), 326 .fd = new_fd, 327 .timer = ((struct itimerval) 328 { { 0, 1000000 / hz() }, 329 { 0, 1000000 / hz() }})}); 330 get_safe_registers(regs); 331 332 /* Set parent's instruction pointer to start of clone-stub */ 333 regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE + 334 (unsigned long) stub_clone_handler - 335 (unsigned long) &__syscall_stub_start; 336 regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE - 337 sizeof(void *); 338 err = ptrace_setregs(pid, regs); 339 if(err < 0) 340 panic("copy_context_skas0 : PTRACE_SETREGS failed, " 341 "pid = %d, errno = %d\n", pid, errno); 342 343 /* set a well known return code for detection of child write failure */ 344 child_data->err = 12345678; 345 346 /* Wait, until parent has finished its work: read child's pid from 347 * parent's stack, and check, if bad result. 348 */ 349 wait_stub_done(pid, 0, "copy_context_skas0"); 350 351 pid = data->err; 352 if(pid < 0) 353 panic("copy_context_skas0 - stub-parent reports error %d\n", 354 pid); 355 356 /* Wait, until child has finished too: read child's result from 357 * child's stack and check it. 358 */ 359 wait_stub_done(pid, -1, "copy_context_skas0"); 360 if (child_data->err != UML_CONFIG_STUB_DATA) 361 panic("copy_context_skas0 - stub-child reports error %d\n", 362 child_data->err); 363 364 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, 365 (void *)PTRACE_O_TRACESYSGOOD) < 0) 366 panic("copy_context_skas0 : PTRACE_SETOPTIONS failed, " 367 "errno = %d\n", errno); 368 369 return pid; 370 } 371 372 /* 373 * This is used only, if proc_mm is available, while PTRACE_FAULTINFO 374 * isn't. Opening /proc/mm creates a new mm_context, which lacks the stub-pages 375 * Thus, we map them using /proc/mm-fd 376 */ 377 void map_stub_pages(int fd, unsigned long code, 378 unsigned long data, unsigned long stack) 379 { 380 struct proc_mm_op mmop; 381 int n; 382 383 mmop = ((struct proc_mm_op) { .op = MM_MMAP, 384 .u = 385 { .mmap = 386 { .addr = code, 387 .len = PAGE_SIZE, 388 .prot = PROT_EXEC, 389 .flags = MAP_FIXED | MAP_PRIVATE, 390 .fd = stub_code_fd, 391 .offset = stub_code_offset 392 } } }); 393 n = os_write_file(fd, &mmop, sizeof(mmop)); 394 if(n != sizeof(mmop)) 395 panic("map_stub_pages : /proc/mm map for code failed, " 396 "err = %d\n", -n); 397 398 if ( stack ) { 399 __u64 map_offset; 400 int map_fd = phys_mapping(to_phys((void *)stack), &map_offset); 401 mmop = ((struct proc_mm_op) 402 { .op = MM_MMAP, 403 .u = 404 { .mmap = 405 { .addr = data, 406 .len = PAGE_SIZE, 407 .prot = PROT_READ | PROT_WRITE, 408 .flags = MAP_FIXED | MAP_SHARED, 409 .fd = map_fd, 410 .offset = map_offset 411 } } }); 412 n = os_write_file(fd, &mmop, sizeof(mmop)); 413 if(n != sizeof(mmop)) 414 panic("map_stub_pages : /proc/mm map for data failed, " 415 "err = %d\n", -n); 416 } 417 } 418 419 void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr, 420 void (*handler)(int)) 421 { 422 unsigned long flags; 423 sigjmp_buf switch_buf, fork_buf; 424 425 *switch_buf_ptr = &switch_buf; 426 *fork_buf_ptr = &fork_buf; 427 428 /* Somewhat subtle - siglongjmp restores the signal mask before doing 429 * the longjmp. This means that when jumping from one stack to another 430 * when the target stack has interrupts enabled, an interrupt may occur 431 * on the source stack. This is bad when starting up a process because 432 * it's not supposed to get timer ticks until it has been scheduled. 433 * So, we disable interrupts around the sigsetjmp to ensure that 434 * they can't happen until we get back here where they are safe. 435 */ 436 flags = get_signals(); 437 block_signals(); 438 if(sigsetjmp(fork_buf, 1) == 0) 439 new_thread_proc(stack, handler); 440 441 remove_sigstack(); 442 443 set_signals(flags); 444 } 445 446 void thread_wait(void *sw, void *fb) 447 { 448 sigjmp_buf buf, **switch_buf = sw, *fork_buf; 449 450 *switch_buf = &buf; 451 fork_buf = fb; 452 if(sigsetjmp(buf, 1) == 0) 453 siglongjmp(*fork_buf, INIT_JMP_REMOVE_SIGSTACK); 454 } 455 456 void switch_threads(void *me, void *next) 457 { 458 sigjmp_buf my_buf, **me_ptr = me, *next_buf = next; 459 460 *me_ptr = &my_buf; 461 if(sigsetjmp(my_buf, 1) == 0) 462 siglongjmp(*next_buf, 1); 463 } 464 465 static sigjmp_buf initial_jmpbuf; 466 467 /* XXX Make these percpu */ 468 static void (*cb_proc)(void *arg); 469 static void *cb_arg; 470 static sigjmp_buf *cb_back; 471 472 int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr) 473 { 474 sigjmp_buf **switch_buf = switch_buf_ptr; 475 int n; 476 477 set_handler(SIGWINCH, (__sighandler_t) sig_handler, 478 SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM, 479 SIGVTALRM, -1); 480 481 *fork_buf_ptr = &initial_jmpbuf; 482 n = sigsetjmp(initial_jmpbuf, 1); 483 switch(n){ 484 case INIT_JMP_NEW_THREAD: 485 new_thread_proc((void *) stack, new_thread_handler); 486 break; 487 case INIT_JMP_REMOVE_SIGSTACK: 488 remove_sigstack(); 489 break; 490 case INIT_JMP_CALLBACK: 491 (*cb_proc)(cb_arg); 492 siglongjmp(*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 siglongjmp(**switch_buf, 1); 504 } 505 506 void remove_sigstack(void) 507 { 508 stack_t stack = ((stack_t) { .ss_flags = SS_DISABLE, 509 .ss_sp = NULL, 510 .ss_size = 0 }); 511 512 if(sigaltstack(&stack, NULL) != 0) 513 panic("disabling signal stack failed, errno = %d\n", errno); 514 } 515 516 void initial_thread_cb_skas(void (*proc)(void *), void *arg) 517 { 518 sigjmp_buf here; 519 520 cb_proc = proc; 521 cb_arg = arg; 522 cb_back = &here; 523 524 block_signals(); 525 if(sigsetjmp(here, 1) == 0) 526 siglongjmp(initial_jmpbuf, INIT_JMP_CALLBACK); 527 unblock_signals(); 528 529 cb_proc = NULL; 530 cb_arg = NULL; 531 cb_back = NULL; 532 } 533 534 void halt_skas(void) 535 { 536 block_signals(); 537 siglongjmp(initial_jmpbuf, INIT_JMP_HALT); 538 } 539 540 void reboot_skas(void) 541 { 542 block_signals(); 543 siglongjmp(initial_jmpbuf, INIT_JMP_REBOOT); 544 } 545 546 void switch_mm_skas(struct mm_id *mm_idp) 547 { 548 int err; 549 550 #warning need cpu pid in switch_mm_skas 551 if(proc_mm){ 552 err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0, 553 mm_idp->u.mm_fd); 554 if(err) 555 panic("switch_mm_skas - PTRACE_SWITCH_MM failed, " 556 "errno = %d\n", errno); 557 } 558 else userspace_pid[0] = mm_idp->u.pid; 559 } 560 561 /* 562 * Overrides for Emacs so that we follow Linus's tabbing style. 563 * Emacs will notice this stuff at the end of the file and automatically 564 * adjust the settings for this buffer only. This must remain at the end 565 * of the file. 566 * --------------------------------------------------------------------------- 567 * Local variables: 568 * c-file-style: "linux" 569 * End: 570 */ 571