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 #include "kern_constants.h" 37 38 int is_skas_winch(int pid, int fd, void *data) 39 { 40 if(pid != os_getpgrp()) 41 return(0); 42 43 register_winch_irq(-1, fd, -1, data); 44 return(1); 45 } 46 47 static int ptrace_dump_regs(int pid) 48 { 49 unsigned long regs[MAX_REG_NR]; 50 int i; 51 52 if(ptrace(PTRACE_GETREGS, pid, 0, regs) < 0) 53 return -errno; 54 else { 55 printk("Stub registers -\n"); 56 for(i = 0; i < ARRAY_SIZE(regs); i++) 57 printk("\t%d - %lx\n", i, regs[i]); 58 } 59 60 return 0; 61 } 62 63 void wait_stub_done(int pid, int sig, char * fname) 64 { 65 int n, status, err; 66 67 do { 68 if ( sig != -1 ) { 69 err = ptrace(PTRACE_CONT, pid, 0, sig); 70 if(err) 71 panic("%s : continue failed, errno = %d\n", 72 fname, errno); 73 } 74 sig = 0; 75 76 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); 77 } while((n >= 0) && WIFSTOPPED(status) && 78 ((WSTOPSIG(status) == SIGVTALRM) || 79 /* running UML inside a detached screen can cause 80 * SIGWINCHes 81 */ 82 (WSTOPSIG(status) == SIGWINCH))); 83 84 if((n < 0) || !WIFSTOPPED(status) || 85 (WSTOPSIG(status) != SIGUSR1 && WSTOPSIG(status) != SIGTRAP)){ 86 err = ptrace_dump_regs(pid); 87 if(err) 88 printk("Failed to get registers from stub, " 89 "errno = %d\n", -err); 90 panic("%s : failed to wait for SIGUSR1/SIGTRAP, " 91 "pid = %d, n = %d, errno = %d, status = 0x%x\n", 92 fname, pid, n, errno, status); 93 } 94 } 95 96 extern unsigned long current_stub_stack(void); 97 98 void get_skas_faultinfo(int pid, struct faultinfo * fi) 99 { 100 int err; 101 102 if(ptrace_faultinfo){ 103 err = ptrace(PTRACE_FAULTINFO, pid, 0, fi); 104 if(err) 105 panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, " 106 "errno = %d\n", errno); 107 108 /* Special handling for i386, which has different structs */ 109 if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo)) 110 memset((char *)fi + sizeof(struct ptrace_faultinfo), 0, 111 sizeof(struct faultinfo) - 112 sizeof(struct ptrace_faultinfo)); 113 } 114 else { 115 wait_stub_done(pid, SIGSEGV, "get_skas_faultinfo"); 116 117 /* faultinfo is prepared by the stub-segv-handler at start of 118 * the stub stack page. We just have to copy it. 119 */ 120 memcpy(fi, (void *)current_stub_stack(), sizeof(*fi)); 121 } 122 } 123 124 static void handle_segv(int pid, union uml_pt_regs * regs) 125 { 126 get_skas_faultinfo(pid, ®s->skas.faultinfo); 127 segv(regs->skas.faultinfo, 0, 1, NULL); 128 } 129 130 /*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/ 131 static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu) 132 { 133 int err, status; 134 135 /* Mark this as a syscall */ 136 UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->skas.regs); 137 138 if (!local_using_sysemu) 139 { 140 err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET, 141 __NR_getpid); 142 if(err < 0) 143 panic("handle_trap - nullifying syscall failed errno = %d\n", 144 errno); 145 146 err = ptrace(PTRACE_SYSCALL, pid, 0, 0); 147 if(err < 0) 148 panic("handle_trap - continuing to end of syscall failed, " 149 "errno = %d\n", errno); 150 151 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED)); 152 if((err < 0) || !WIFSTOPPED(status) || 153 (WSTOPSIG(status) != SIGTRAP + 0x80)){ 154 err = ptrace_dump_regs(pid); 155 if(err) 156 printk("Failed to get registers from process, " 157 "errno = %d\n", -err); 158 panic("handle_trap - failed to wait at end of syscall, " 159 "errno = %d, status = %d\n", errno, status); 160 } 161 } 162 163 handle_syscall(regs); 164 } 165 166 extern int __syscall_stub_start; 167 168 static int userspace_tramp(void *stack) 169 { 170 void *addr; 171 int err; 172 173 ptrace(PTRACE_TRACEME, 0, 0, 0); 174 175 init_new_thread_signals(); 176 err = set_interval(1); 177 if(err) 178 panic("userspace_tramp - setting timer failed, errno = %d\n", 179 err); 180 181 if(!proc_mm){ 182 /* This has a pte, but it can't be mapped in with the usual 183 * tlb_flush mechanism because this is part of that mechanism 184 */ 185 int fd; 186 __u64 offset; 187 fd = phys_mapping(to_phys(&__syscall_stub_start), &offset); 188 addr = mmap64((void *) UML_CONFIG_STUB_CODE, UM_KERN_PAGE_SIZE, 189 PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset); 190 if(addr == MAP_FAILED){ 191 printk("mapping mmap stub failed, errno = %d\n", 192 errno); 193 exit(1); 194 } 195 196 if(stack != NULL){ 197 fd = phys_mapping(to_phys(stack), &offset); 198 addr = mmap((void *) UML_CONFIG_STUB_DATA, 199 UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE, 200 MAP_FIXED | MAP_SHARED, fd, offset); 201 if(addr == MAP_FAILED){ 202 printk("mapping segfault stack failed, " 203 "errno = %d\n", errno); 204 exit(1); 205 } 206 } 207 } 208 if(!ptrace_faultinfo && (stack != NULL)){ 209 struct sigaction sa; 210 211 unsigned long v = UML_CONFIG_STUB_CODE + 212 (unsigned long) stub_segv_handler - 213 (unsigned long) &__syscall_stub_start; 214 215 set_sigstack((void *) UML_CONFIG_STUB_DATA, UM_KERN_PAGE_SIZE); 216 sigemptyset(&sa.sa_mask); 217 sigaddset(&sa.sa_mask, SIGIO); 218 sigaddset(&sa.sa_mask, SIGWINCH); 219 sigaddset(&sa.sa_mask, SIGALRM); 220 sigaddset(&sa.sa_mask, SIGVTALRM); 221 sigaddset(&sa.sa_mask, SIGUSR1); 222 sa.sa_flags = SA_ONSTACK; 223 sa.sa_handler = (void *) v; 224 sa.sa_restorer = NULL; 225 if(sigaction(SIGSEGV, &sa, NULL) < 0) 226 panic("userspace_tramp - setting SIGSEGV handler " 227 "failed - errno = %d\n", errno); 228 } 229 230 os_stop_process(os_getpid()); 231 return(0); 232 } 233 234 /* Each element set once, and only accessed by a single processor anyway */ 235 #undef NR_CPUS 236 #define NR_CPUS 1 237 int userspace_pid[NR_CPUS]; 238 239 int start_userspace(unsigned long stub_stack) 240 { 241 void *stack; 242 unsigned long sp; 243 int pid, status, n, flags; 244 245 stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC, 246 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); 247 if(stack == MAP_FAILED) 248 panic("start_userspace : mmap failed, errno = %d", errno); 249 sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *); 250 251 flags = CLONE_FILES | SIGCHLD; 252 if(proc_mm) flags |= CLONE_VM; 253 pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack); 254 if(pid < 0) 255 panic("start_userspace : clone failed, errno = %d", errno); 256 257 do { 258 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); 259 if(n < 0) 260 panic("start_userspace : wait failed, errno = %d", 261 errno); 262 } while(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM)); 263 264 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) 265 panic("start_userspace : expected SIGSTOP, got status = %d", 266 status); 267 268 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, (void *)PTRACE_O_TRACESYSGOOD) < 0) 269 panic("start_userspace : PTRACE_OLDSETOPTIONS failed, errno=%d\n", 270 errno); 271 272 if(munmap(stack, PAGE_SIZE) < 0) 273 panic("start_userspace : munmap failed, errno = %d\n", errno); 274 275 return(pid); 276 } 277 278 void userspace(union uml_pt_regs *regs) 279 { 280 int err, status, op, pid = userspace_pid[0]; 281 int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/ 282 283 while(1){ 284 restore_registers(pid, regs); 285 286 /* Now we set local_using_sysemu to be used for one loop */ 287 local_using_sysemu = get_using_sysemu(); 288 289 op = SELECT_PTRACE_OPERATION(local_using_sysemu, singlestepping(NULL)); 290 291 err = ptrace(op, pid, 0, 0); 292 if(err) 293 panic("userspace - could not resume userspace process, " 294 "pid=%d, ptrace operation = %d, errno = %d\n", 295 pid, op, errno); 296 297 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED)); 298 if(err < 0) 299 panic("userspace - waitpid failed, errno = %d\n", 300 errno); 301 302 regs->skas.is_user = 1; 303 save_registers(pid, regs); 304 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */ 305 306 if(WIFSTOPPED(status)){ 307 switch(WSTOPSIG(status)){ 308 case SIGSEGV: 309 if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo) 310 user_signal(SIGSEGV, regs, pid); 311 else handle_segv(pid, regs); 312 break; 313 case SIGTRAP + 0x80: 314 handle_trap(pid, regs, local_using_sysemu); 315 break; 316 case SIGTRAP: 317 relay_signal(SIGTRAP, regs); 318 break; 319 case SIGIO: 320 case SIGVTALRM: 321 case SIGILL: 322 case SIGBUS: 323 case SIGFPE: 324 case SIGWINCH: 325 user_signal(WSTOPSIG(status), regs, pid); 326 break; 327 default: 328 printk("userspace - child stopped with signal " 329 "%d\n", WSTOPSIG(status)); 330 } 331 pid = userspace_pid[0]; 332 interrupt_end(); 333 334 /* Avoid -ERESTARTSYS handling in host */ 335 if(PT_SYSCALL_NR_OFFSET != PT_SYSCALL_RET_OFFSET) 336 PT_SYSCALL_NR(regs->skas.regs) = -1; 337 } 338 } 339 } 340 341 int copy_context_skas0(unsigned long new_stack, int pid) 342 { 343 int err; 344 unsigned long regs[MAX_REG_NR]; 345 unsigned long fp_regs[HOST_FP_SIZE]; 346 unsigned long current_stack = current_stub_stack(); 347 struct stub_data *data = (struct stub_data *) current_stack; 348 struct stub_data *child_data = (struct stub_data *) new_stack; 349 __u64 new_offset; 350 int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset); 351 352 /* prepare offset and fd of child's stack as argument for parent's 353 * and child's mmap2 calls 354 */ 355 *data = ((struct stub_data) { .offset = MMAP_OFFSET(new_offset), 356 .fd = new_fd, 357 .timer = ((struct itimerval) 358 { { 0, 1000000 / hz() }, 359 { 0, 1000000 / hz() }})}); 360 get_safe_registers(regs, fp_regs); 361 362 /* Set parent's instruction pointer to start of clone-stub */ 363 regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE + 364 (unsigned long) stub_clone_handler - 365 (unsigned long) &__syscall_stub_start; 366 regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE - 367 sizeof(void *); 368 #ifdef __SIGNAL_FRAMESIZE 369 regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE; 370 #endif 371 err = ptrace_setregs(pid, regs); 372 if(err < 0) 373 panic("copy_context_skas0 : PTRACE_SETREGS failed, " 374 "pid = %d, errno = %d\n", pid, -err); 375 376 err = ptrace_setfpregs(pid, fp_regs); 377 if(err < 0) 378 panic("copy_context_skas0 : PTRACE_SETFPREGS failed, " 379 "pid = %d, errno = %d\n", pid, -err); 380 381 /* set a well known return code for detection of child write failure */ 382 child_data->err = 12345678; 383 384 /* Wait, until parent has finished its work: read child's pid from 385 * parent's stack, and check, if bad result. 386 */ 387 wait_stub_done(pid, 0, "copy_context_skas0"); 388 389 pid = data->err; 390 if(pid < 0) 391 panic("copy_context_skas0 - stub-parent reports error %d\n", 392 -pid); 393 394 /* Wait, until child has finished too: read child's result from 395 * child's stack and check it. 396 */ 397 wait_stub_done(pid, -1, "copy_context_skas0"); 398 if (child_data->err != UML_CONFIG_STUB_DATA) 399 panic("copy_context_skas0 - stub-child reports error %ld\n", 400 child_data->err); 401 402 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, 403 (void *)PTRACE_O_TRACESYSGOOD) < 0) 404 panic("copy_context_skas0 : PTRACE_OLDSETOPTIONS failed, " 405 "errno = %d\n", errno); 406 407 return pid; 408 } 409 410 /* 411 * This is used only, if stub pages are needed, while proc_mm is 412 * available. Opening /proc/mm creates a new mm_context, which lacks 413 * the stub-pages. Thus, we map them using /proc/mm-fd 414 */ 415 void map_stub_pages(int fd, unsigned long code, 416 unsigned long data, unsigned long stack) 417 { 418 struct proc_mm_op mmop; 419 int n; 420 __u64 code_offset; 421 int code_fd = phys_mapping(to_phys((void *) &__syscall_stub_start), 422 &code_offset); 423 424 mmop = ((struct proc_mm_op) { .op = MM_MMAP, 425 .u = 426 { .mmap = 427 { .addr = code, 428 .len = PAGE_SIZE, 429 .prot = PROT_EXEC, 430 .flags = MAP_FIXED | MAP_PRIVATE, 431 .fd = code_fd, 432 .offset = code_offset 433 } } }); 434 CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop))); 435 if(n != sizeof(mmop)){ 436 n = errno; 437 printk("mmap args - addr = 0x%lx, fd = %d, offset = %llx\n", 438 code, code_fd, (unsigned long long) code_offset); 439 panic("map_stub_pages : /proc/mm map for code failed, " 440 "err = %d\n", n); 441 } 442 443 if ( stack ) { 444 __u64 map_offset; 445 int map_fd = phys_mapping(to_phys((void *)stack), &map_offset); 446 mmop = ((struct proc_mm_op) 447 { .op = MM_MMAP, 448 .u = 449 { .mmap = 450 { .addr = data, 451 .len = PAGE_SIZE, 452 .prot = PROT_READ | PROT_WRITE, 453 .flags = MAP_FIXED | MAP_SHARED, 454 .fd = map_fd, 455 .offset = map_offset 456 } } }); 457 CATCH_EINTR(n = write(fd, &mmop, sizeof(mmop))); 458 if(n != sizeof(mmop)) 459 panic("map_stub_pages : /proc/mm map for data failed, " 460 "err = %d\n", errno); 461 } 462 } 463 464 void new_thread(void *stack, jmp_buf *buf, void (*handler)(void)) 465 { 466 (*buf)[0].JB_IP = (unsigned long) handler; 467 (*buf)[0].JB_SP = (unsigned long) stack + 468 (PAGE_SIZE << UML_CONFIG_KERNEL_STACK_ORDER) - sizeof(void *); 469 } 470 471 #define INIT_JMP_NEW_THREAD 0 472 #define INIT_JMP_CALLBACK 1 473 #define INIT_JMP_HALT 2 474 #define INIT_JMP_REBOOT 3 475 476 void switch_threads(jmp_buf *me, jmp_buf *you) 477 { 478 if(UML_SETJMP(me) == 0) 479 UML_LONGJMP(you, 1); 480 } 481 482 static jmp_buf initial_jmpbuf; 483 484 /* XXX Make these percpu */ 485 static void (*cb_proc)(void *arg); 486 static void *cb_arg; 487 static jmp_buf *cb_back; 488 489 int start_idle_thread(void *stack, jmp_buf *switch_buf) 490 { 491 int n; 492 493 set_handler(SIGWINCH, (__sighandler_t) sig_handler, 494 SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM, 495 SIGVTALRM, -1); 496 497 n = UML_SETJMP(&initial_jmpbuf); 498 switch(n){ 499 case INIT_JMP_NEW_THREAD: 500 (*switch_buf)[0].JB_IP = (unsigned long) new_thread_handler; 501 (*switch_buf)[0].JB_SP = (unsigned long) stack + 502 (PAGE_SIZE << UML_CONFIG_KERNEL_STACK_ORDER) - 503 sizeof(void *); 504 break; 505 case INIT_JMP_CALLBACK: 506 (*cb_proc)(cb_arg); 507 UML_LONGJMP(cb_back, 1); 508 break; 509 case INIT_JMP_HALT: 510 kmalloc_ok = 0; 511 return(0); 512 case INIT_JMP_REBOOT: 513 kmalloc_ok = 0; 514 return(1); 515 default: 516 panic("Bad sigsetjmp return in start_idle_thread - %d\n", n); 517 } 518 UML_LONGJMP(switch_buf, 1); 519 } 520 521 void initial_thread_cb_skas(void (*proc)(void *), void *arg) 522 { 523 jmp_buf here; 524 525 cb_proc = proc; 526 cb_arg = arg; 527 cb_back = &here; 528 529 block_signals(); 530 if(UML_SETJMP(&here) == 0) 531 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK); 532 unblock_signals(); 533 534 cb_proc = NULL; 535 cb_arg = NULL; 536 cb_back = NULL; 537 } 538 539 void halt_skas(void) 540 { 541 block_signals(); 542 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT); 543 } 544 545 void reboot_skas(void) 546 { 547 block_signals(); 548 UML_LONGJMP(&initial_jmpbuf, INIT_JMP_REBOOT); 549 } 550 551 void switch_mm_skas(struct mm_id *mm_idp) 552 { 553 int err; 554 555 #warning need cpu pid in switch_mm_skas 556 if(proc_mm){ 557 err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0, 558 mm_idp->u.mm_fd); 559 if(err) 560 panic("switch_mm_skas - PTRACE_SWITCH_MM failed, " 561 "errno = %d\n", errno); 562 } 563 else userspace_pid[0] = mm_idp->u.pid; 564 } 565