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 "registers.h" 35 #include "mem.h" 36 #include "uml-config.h" 37 #include "process.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[FRAME_SIZE]; 72 if(ptrace(PTRACE_GETREGS, pid, 0, regs) < 0) 73 printk("Failed to get registers from stub, " 74 "errno = %d\n", errno); 75 else { 76 int i; 77 78 printk("Stub registers -\n"); 79 for(i = 0; i < FRAME_SIZE; i++) 80 printk("\t%d - %lx\n", i, regs[i]); 81 } 82 panic("%s : failed to wait for SIGUSR1/SIGTRAP, " 83 "pid = %d, n = %d, errno = %d, status = 0x%x\n", 84 fname, pid, n, errno, status); 85 } 86 } 87 88 void get_skas_faultinfo(int pid, struct faultinfo * fi) 89 { 90 int err; 91 92 if(ptrace_faultinfo){ 93 err = ptrace(PTRACE_FAULTINFO, pid, 0, fi); 94 if(err) 95 panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, " 96 "errno = %d\n", errno); 97 98 /* Special handling for i386, which has different structs */ 99 if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo)) 100 memset((char *)fi + sizeof(struct ptrace_faultinfo), 0, 101 sizeof(struct faultinfo) - 102 sizeof(struct ptrace_faultinfo)); 103 } 104 else { 105 wait_stub_done(pid, SIGSEGV, "get_skas_faultinfo"); 106 107 /* faultinfo is prepared by the stub-segv-handler at start of 108 * the stub stack page. We just have to copy it. 109 */ 110 memcpy(fi, (void *)current_stub_stack(), sizeof(*fi)); 111 } 112 } 113 114 static void handle_segv(int pid, union uml_pt_regs * regs) 115 { 116 get_skas_faultinfo(pid, ®s->skas.faultinfo); 117 segv(regs->skas.faultinfo, 0, 1, NULL); 118 } 119 120 /*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/ 121 static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu) 122 { 123 int err, status; 124 125 /* Mark this as a syscall */ 126 UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->skas.regs); 127 128 if (!local_using_sysemu) 129 { 130 err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET, __NR_getpid); 131 if(err < 0) 132 panic("handle_trap - nullifying syscall failed errno = %d\n", 133 errno); 134 135 err = ptrace(PTRACE_SYSCALL, pid, 0, 0); 136 if(err < 0) 137 panic("handle_trap - continuing to end of syscall failed, " 138 "errno = %d\n", errno); 139 140 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED)); 141 if((err < 0) || !WIFSTOPPED(status) || 142 (WSTOPSIG(status) != SIGTRAP + 0x80)) 143 panic("handle_trap - failed to wait at end of syscall, " 144 "errno = %d, status = %d\n", errno, status); 145 } 146 147 handle_syscall(regs); 148 } 149 150 extern int __syscall_stub_start; 151 int stub_code_fd = -1; 152 __u64 stub_code_offset; 153 154 static int userspace_tramp(void *stack) 155 { 156 void *addr; 157 158 ptrace(PTRACE_TRACEME, 0, 0, 0); 159 160 init_new_thread_signals(1); 161 enable_timer(); 162 163 if(!proc_mm){ 164 /* This has a pte, but it can't be mapped in with the usual 165 * tlb_flush mechanism because this is part of that mechanism 166 */ 167 addr = mmap64((void *) UML_CONFIG_STUB_CODE, page_size(), 168 PROT_EXEC, MAP_FIXED | MAP_PRIVATE, 169 stub_code_fd, stub_code_offset); 170 if(addr == MAP_FAILED){ 171 printk("mapping stub code failed, errno = %d\n", 172 errno); 173 exit(1); 174 } 175 176 if(stack != NULL){ 177 int fd; 178 __u64 offset; 179 180 fd = phys_mapping(to_phys(stack), &offset); 181 addr = mmap((void *) UML_CONFIG_STUB_DATA, page_size(), 182 PROT_READ | PROT_WRITE, 183 MAP_FIXED | MAP_SHARED, fd, offset); 184 if(addr == MAP_FAILED){ 185 printk("mapping stub stack failed, " 186 "errno = %d\n", errno); 187 exit(1); 188 } 189 } 190 } 191 if(!ptrace_faultinfo){ 192 unsigned long v = UML_CONFIG_STUB_CODE + 193 (unsigned long) stub_segv_handler - 194 (unsigned long) &__syscall_stub_start; 195 196 set_sigstack((void *) UML_CONFIG_STUB_DATA, page_size()); 197 set_handler(SIGSEGV, (void *) v, SA_ONSTACK, 198 SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, 199 SIGUSR1, -1); 200 } 201 202 os_stop_process(os_getpid()); 203 return(0); 204 } 205 206 /* Each element set once, and only accessed by a single processor anyway */ 207 #undef NR_CPUS 208 #define NR_CPUS 1 209 int userspace_pid[NR_CPUS]; 210 211 int start_userspace(unsigned long stub_stack) 212 { 213 void *stack; 214 unsigned long sp; 215 int pid, status, n, flags; 216 217 if ( stub_code_fd == -1 ) 218 stub_code_fd = phys_mapping(to_phys(&__syscall_stub_start), 219 &stub_code_offset); 220 221 stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC, 222 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); 223 if(stack == MAP_FAILED) 224 panic("start_userspace : mmap failed, errno = %d", errno); 225 sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *); 226 227 flags = CLONE_FILES | SIGCHLD; 228 if(proc_mm) flags |= CLONE_VM; 229 pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack); 230 if(pid < 0) 231 panic("start_userspace : clone failed, errno = %d", errno); 232 233 do { 234 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); 235 if(n < 0) 236 panic("start_userspace : wait failed, errno = %d", 237 errno); 238 } while(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM)); 239 240 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) 241 panic("start_userspace : expected SIGSTOP, got status = %d", 242 status); 243 244 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, (void *)PTRACE_O_TRACESYSGOOD) < 0) 245 panic("start_userspace : PTRACE_SETOPTIONS failed, errno=%d\n", 246 errno); 247 248 if(munmap(stack, PAGE_SIZE) < 0) 249 panic("start_userspace : munmap failed, errno = %d\n", errno); 250 251 return(pid); 252 } 253 254 void userspace(union uml_pt_regs *regs) 255 { 256 int err, status, op, pid = userspace_pid[0]; 257 int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/ 258 259 while(1){ 260 restore_registers(pid, regs); 261 262 /* Now we set local_using_sysemu to be used for one loop */ 263 local_using_sysemu = get_using_sysemu(); 264 265 op = SELECT_PTRACE_OPERATION(local_using_sysemu, singlestepping(NULL)); 266 267 err = ptrace(op, pid, 0, 0); 268 if(err) 269 panic("userspace - could not resume userspace process, " 270 "pid=%d, ptrace operation = %d, errno = %d\n", 271 op, errno); 272 273 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED)); 274 if(err < 0) 275 panic("userspace - waitpid failed, errno = %d\n", 276 errno); 277 278 regs->skas.is_user = 1; 279 save_registers(pid, regs); 280 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */ 281 282 if(WIFSTOPPED(status)){ 283 switch(WSTOPSIG(status)){ 284 case SIGSEGV: 285 if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo) 286 user_signal(SIGSEGV, regs, pid); 287 else handle_segv(pid, regs); 288 break; 289 case SIGTRAP + 0x80: 290 handle_trap(pid, regs, local_using_sysemu); 291 break; 292 case SIGTRAP: 293 relay_signal(SIGTRAP, regs); 294 break; 295 case SIGIO: 296 case SIGVTALRM: 297 case SIGILL: 298 case SIGBUS: 299 case SIGFPE: 300 case SIGWINCH: 301 user_signal(WSTOPSIG(status), regs, pid); 302 break; 303 default: 304 printk("userspace - child stopped with signal " 305 "%d\n", WSTOPSIG(status)); 306 } 307 pid = userspace_pid[0]; 308 interrupt_end(); 309 310 /* Avoid -ERESTARTSYS handling in host */ 311 PT_SYSCALL_NR(regs->skas.regs) = -1; 312 } 313 } 314 } 315 #define INIT_JMP_NEW_THREAD 0 316 #define INIT_JMP_REMOVE_SIGSTACK 1 317 #define INIT_JMP_CALLBACK 2 318 #define INIT_JMP_HALT 3 319 #define INIT_JMP_REBOOT 4 320 321 322 int copy_context_skas0(unsigned long new_stack, int pid) 323 { 324 int err; 325 unsigned long regs[MAX_REG_NR]; 326 unsigned long current_stack = current_stub_stack(); 327 struct stub_data *data = (struct stub_data *) current_stack; 328 struct stub_data *child_data = (struct stub_data *) new_stack; 329 __u64 new_offset; 330 int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset); 331 332 /* prepare offset and fd of child's stack as argument for parent's 333 * and child's mmap2 calls 334 */ 335 *data = ((struct stub_data) { .offset = MMAP_OFFSET(new_offset), 336 .fd = new_fd, 337 .timer = ((struct itimerval) 338 { { 0, 1000000 / hz() }, 339 { 0, 1000000 / hz() }})}); 340 get_safe_registers(regs); 341 342 /* Set parent's instruction pointer to start of clone-stub */ 343 regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE + 344 (unsigned long) stub_clone_handler - 345 (unsigned long) &__syscall_stub_start; 346 regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE - 347 sizeof(void *); 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_SETOPTIONS 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; 392 393 mmop = ((struct proc_mm_op) { .op = MM_MMAP, 394 .u = 395 { .mmap = 396 { .addr = code, 397 .len = PAGE_SIZE, 398 .prot = PROT_EXEC, 399 .flags = MAP_FIXED | MAP_PRIVATE, 400 .fd = stub_code_fd, 401 .offset = stub_code_offset 402 } } }); 403 n = os_write_file(fd, &mmop, sizeof(mmop)); 404 if(n != sizeof(mmop)) 405 panic("map_stub_pages : /proc/mm map for code failed, " 406 "err = %d\n", -n); 407 408 if ( stack ) { 409 __u64 map_offset; 410 int map_fd = phys_mapping(to_phys((void *)stack), &map_offset); 411 mmop = ((struct proc_mm_op) 412 { .op = MM_MMAP, 413 .u = 414 { .mmap = 415 { .addr = data, 416 .len = PAGE_SIZE, 417 .prot = PROT_READ | PROT_WRITE, 418 .flags = MAP_FIXED | MAP_SHARED, 419 .fd = map_fd, 420 .offset = map_offset 421 } } }); 422 n = os_write_file(fd, &mmop, sizeof(mmop)); 423 if(n != sizeof(mmop)) 424 panic("map_stub_pages : /proc/mm map for data failed, " 425 "err = %d\n", -n); 426 } 427 } 428 429 void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr, 430 void (*handler)(int)) 431 { 432 unsigned long flags; 433 sigjmp_buf switch_buf, fork_buf; 434 435 *switch_buf_ptr = &switch_buf; 436 *fork_buf_ptr = &fork_buf; 437 438 /* Somewhat subtle - siglongjmp restores the signal mask before doing 439 * the longjmp. This means that when jumping from one stack to another 440 * when the target stack has interrupts enabled, an interrupt may occur 441 * on the source stack. This is bad when starting up a process because 442 * it's not supposed to get timer ticks until it has been scheduled. 443 * So, we disable interrupts around the sigsetjmp to ensure that 444 * they can't happen until we get back here where they are safe. 445 */ 446 flags = get_signals(); 447 block_signals(); 448 if(sigsetjmp(fork_buf, 1) == 0) 449 new_thread_proc(stack, handler); 450 451 remove_sigstack(); 452 453 set_signals(flags); 454 } 455 456 void thread_wait(void *sw, void *fb) 457 { 458 sigjmp_buf buf, **switch_buf = sw, *fork_buf; 459 460 *switch_buf = &buf; 461 fork_buf = fb; 462 if(sigsetjmp(buf, 1) == 0) 463 siglongjmp(*fork_buf, INIT_JMP_REMOVE_SIGSTACK); 464 } 465 466 void switch_threads(void *me, void *next) 467 { 468 sigjmp_buf my_buf, **me_ptr = me, *next_buf = next; 469 470 *me_ptr = &my_buf; 471 if(sigsetjmp(my_buf, 1) == 0) 472 siglongjmp(*next_buf, 1); 473 } 474 475 static sigjmp_buf initial_jmpbuf; 476 477 /* XXX Make these percpu */ 478 static void (*cb_proc)(void *arg); 479 static void *cb_arg; 480 static sigjmp_buf *cb_back; 481 482 int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr) 483 { 484 sigjmp_buf **switch_buf = switch_buf_ptr; 485 int n; 486 487 set_handler(SIGWINCH, (__sighandler_t) sig_handler, 488 SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM, 489 SIGVTALRM, -1); 490 491 *fork_buf_ptr = &initial_jmpbuf; 492 n = sigsetjmp(initial_jmpbuf, 1); 493 switch(n){ 494 case INIT_JMP_NEW_THREAD: 495 new_thread_proc((void *) stack, new_thread_handler); 496 break; 497 case INIT_JMP_REMOVE_SIGSTACK: 498 remove_sigstack(); 499 break; 500 case INIT_JMP_CALLBACK: 501 (*cb_proc)(cb_arg); 502 siglongjmp(*cb_back, 1); 503 break; 504 case INIT_JMP_HALT: 505 kmalloc_ok = 0; 506 return(0); 507 case INIT_JMP_REBOOT: 508 kmalloc_ok = 0; 509 return(1); 510 default: 511 panic("Bad sigsetjmp return in start_idle_thread - %d\n", n); 512 } 513 siglongjmp(**switch_buf, 1); 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