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, ®s->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 } 313 314 int copy_context_skas0(unsigned long new_stack, int pid) 315 { 316 int err; 317 unsigned long regs[HOST_FRAME_SIZE]; 318 unsigned long fp_regs[HOST_FP_SIZE]; 319 unsigned long current_stack = current_stub_stack(); 320 struct stub_data *data = (struct stub_data *) current_stack; 321 struct stub_data *child_data = (struct stub_data *) new_stack; 322 __u64 new_offset; 323 int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset); 324 325 /* prepare offset and fd of child's stack as argument for parent's 326 * and child's mmap2 calls 327 */ 328 *data = ((struct stub_data) { .offset = MMAP_OFFSET(new_offset), 329 .fd = new_fd, 330 .timer = ((struct itimerval) 331 { { 0, 1000000 / hz() }, 332 { 0, 1000000 / hz() }})}); 333 get_safe_registers(regs, fp_regs); 334 335 /* Set parent's instruction pointer to start of clone-stub */ 336 regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE + 337 (unsigned long) stub_clone_handler - 338 (unsigned long) &__syscall_stub_start; 339 regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE - 340 sizeof(void *); 341 #ifdef __SIGNAL_FRAMESIZE 342 regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE; 343 #endif 344 err = ptrace_setregs(pid, regs); 345 if(err < 0) 346 panic("copy_context_skas0 : PTRACE_SETREGS failed, " 347 "pid = %d, errno = %d\n", pid, errno); 348 349 err = ptrace_setfpregs(pid, fp_regs); 350 if(err < 0) 351 panic("copy_context_skas0 : PTRACE_SETFPREGS failed, " 352 "pid = %d, errno = %d\n", pid, errno); 353 354 /* set a well known return code for detection of child write failure */ 355 child_data->err = 12345678; 356 357 /* Wait, until parent has finished its work: read child's pid from 358 * parent's stack, and check, if bad result. 359 */ 360 wait_stub_done(pid, 0, "copy_context_skas0"); 361 362 pid = data->err; 363 if(pid < 0) 364 panic("copy_context_skas0 - stub-parent reports error %d\n", 365 pid); 366 367 /* Wait, until child has finished too: read child's result from 368 * child's stack and check it. 369 */ 370 wait_stub_done(pid, -1, "copy_context_skas0"); 371 if (child_data->err != UML_CONFIG_STUB_DATA) 372 panic("copy_context_skas0 - stub-child reports error %d\n", 373 child_data->err); 374 375 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, 376 (void *)PTRACE_O_TRACESYSGOOD) < 0) 377 panic("copy_context_skas0 : PTRACE_OLDSETOPTIONS failed, " 378 "errno = %d\n", errno); 379 380 return pid; 381 } 382 383 /* 384 * This is used only, if stub pages are needed, while proc_mm is 385 * availabl. Opening /proc/mm creates a new mm_context, which lacks 386 * the stub-pages. Thus, we map them using /proc/mm-fd 387 */ 388 void map_stub_pages(int fd, unsigned long code, 389 unsigned long data, unsigned long stack) 390 { 391 struct proc_mm_op mmop; 392 int n; 393 __u64 code_offset; 394 int code_fd = phys_mapping(to_phys((void *) &__syscall_stub_start), 395 &code_offset); 396 397 mmop = ((struct proc_mm_op) { .op = MM_MMAP, 398 .u = 399 { .mmap = 400 { .addr = code, 401 .len = PAGE_SIZE, 402 .prot = PROT_EXEC, 403 .flags = MAP_FIXED | MAP_PRIVATE, 404 .fd = code_fd, 405 .offset = code_offset 406 } } }); 407 n = os_write_file(fd, &mmop, sizeof(mmop)); 408 if(n != sizeof(mmop)) 409 panic("map_stub_pages : /proc/mm map for code failed, " 410 "err = %d\n", -n); 411 412 if ( stack ) { 413 __u64 map_offset; 414 int map_fd = phys_mapping(to_phys((void *)stack), &map_offset); 415 mmop = ((struct proc_mm_op) 416 { .op = MM_MMAP, 417 .u = 418 { .mmap = 419 { .addr = data, 420 .len = PAGE_SIZE, 421 .prot = PROT_READ | PROT_WRITE, 422 .flags = MAP_FIXED | MAP_SHARED, 423 .fd = map_fd, 424 .offset = map_offset 425 } } }); 426 n = os_write_file(fd, &mmop, sizeof(mmop)); 427 if(n != sizeof(mmop)) 428 panic("map_stub_pages : /proc/mm map for data failed, " 429 "err = %d\n", -n); 430 } 431 } 432 433 void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr, 434 void (*handler)(int)) 435 { 436 unsigned long flags; 437 sigjmp_buf switch_buf, fork_buf; 438 int enable; 439 440 *switch_buf_ptr = &switch_buf; 441 *fork_buf_ptr = &fork_buf; 442 443 /* Somewhat subtle - siglongjmp restores the signal mask before doing 444 * the longjmp. This means that when jumping from one stack to another 445 * when the target stack has interrupts enabled, an interrupt may occur 446 * on the source stack. This is bad when starting up a process because 447 * it's not supposed to get timer ticks until it has been scheduled. 448 * So, we disable interrupts around the sigsetjmp to ensure that 449 * they can't happen until we get back here where they are safe. 450 */ 451 flags = get_signals(); 452 block_signals(); 453 if(UML_SIGSETJMP(&fork_buf, enable) == 0) 454 new_thread_proc(stack, handler); 455 456 remove_sigstack(); 457 458 set_signals(flags); 459 } 460 461 #define INIT_JMP_NEW_THREAD 0 462 #define INIT_JMP_REMOVE_SIGSTACK 1 463 #define INIT_JMP_CALLBACK 2 464 #define INIT_JMP_HALT 3 465 #define INIT_JMP_REBOOT 4 466 467 void thread_wait(void *sw, void *fb) 468 { 469 sigjmp_buf buf, **switch_buf = sw, *fork_buf; 470 int enable; 471 472 *switch_buf = &buf; 473 fork_buf = fb; 474 if(UML_SIGSETJMP(&buf, enable) == 0) 475 siglongjmp(*fork_buf, INIT_JMP_REMOVE_SIGSTACK); 476 } 477 478 void switch_threads(void *me, void *next) 479 { 480 sigjmp_buf my_buf, **me_ptr = me, *next_buf = next; 481 int enable; 482 483 *me_ptr = &my_buf; 484 if(UML_SIGSETJMP(&my_buf, enable) == 0) 485 UML_SIGLONGJMP(next_buf, 1); 486 } 487 488 static sigjmp_buf initial_jmpbuf; 489 490 /* XXX Make these percpu */ 491 static void (*cb_proc)(void *arg); 492 static void *cb_arg; 493 static sigjmp_buf *cb_back; 494 495 int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr) 496 { 497 sigjmp_buf **switch_buf = switch_buf_ptr; 498 int n, enable; 499 500 set_handler(SIGWINCH, (__sighandler_t) sig_handler, 501 SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM, 502 SIGVTALRM, -1); 503 504 *fork_buf_ptr = &initial_jmpbuf; 505 n = UML_SIGSETJMP(&initial_jmpbuf, enable); 506 switch(n){ 507 case INIT_JMP_NEW_THREAD: 508 new_thread_proc((void *) stack, new_thread_handler); 509 break; 510 case INIT_JMP_REMOVE_SIGSTACK: 511 remove_sigstack(); 512 break; 513 case INIT_JMP_CALLBACK: 514 (*cb_proc)(cb_arg); 515 UML_SIGLONGJMP(cb_back, 1); 516 break; 517 case INIT_JMP_HALT: 518 kmalloc_ok = 0; 519 return(0); 520 case INIT_JMP_REBOOT: 521 kmalloc_ok = 0; 522 return(1); 523 default: 524 panic("Bad sigsetjmp return in start_idle_thread - %d\n", n); 525 } 526 UML_SIGLONGJMP(*switch_buf, 1); 527 } 528 529 void initial_thread_cb_skas(void (*proc)(void *), void *arg) 530 { 531 sigjmp_buf here; 532 int enable; 533 534 cb_proc = proc; 535 cb_arg = arg; 536 cb_back = &here; 537 538 block_signals(); 539 if(UML_SIGSETJMP(&here, enable) == 0) 540 UML_SIGLONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK); 541 unblock_signals(); 542 543 cb_proc = NULL; 544 cb_arg = NULL; 545 cb_back = NULL; 546 } 547 548 void halt_skas(void) 549 { 550 block_signals(); 551 UML_SIGLONGJMP(&initial_jmpbuf, INIT_JMP_HALT); 552 } 553 554 void reboot_skas(void) 555 { 556 block_signals(); 557 UML_SIGLONGJMP(&initial_jmpbuf, INIT_JMP_REBOOT); 558 } 559 560 void switch_mm_skas(struct mm_id *mm_idp) 561 { 562 int err; 563 564 #warning need cpu pid in switch_mm_skas 565 if(proc_mm){ 566 err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0, 567 mm_idp->u.mm_fd); 568 if(err) 569 panic("switch_mm_skas - PTRACE_SWITCH_MM failed, " 570 "errno = %d\n", errno); 571 } 572 else userspace_pid[0] = mm_idp->u.pid; 573 } 574