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; 141 142 static int userspace_tramp(void *stack) 143 { 144 void *addr; 145 146 ptrace(PTRACE_TRACEME, 0, 0, 0); 147 148 init_new_thread_signals(1); 149 enable_timer(); 150 151 if(!proc_mm){ 152 /* This has a pte, but it can't be mapped in with the usual 153 * tlb_flush mechanism because this is part of that mechanism 154 */ 155 int fd; 156 __u64 offset; 157 158 fd = phys_mapping(to_phys(&__syscall_stub_start), &offset); 159 addr = mmap64((void *) UML_CONFIG_STUB_CODE, page_size(), 160 PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset); 161 if(addr == MAP_FAILED){ 162 printk("mapping mmap stub failed, errno = %d\n", 163 errno); 164 exit(1); 165 } 166 167 if(stack != NULL){ 168 fd = phys_mapping(to_phys(stack), &offset); 169 addr = mmap((void *) UML_CONFIG_STUB_DATA, page_size(), 170 PROT_READ | PROT_WRITE, 171 MAP_FIXED | MAP_SHARED, fd, offset); 172 if(addr == MAP_FAILED){ 173 printk("mapping segfault stack failed, " 174 "errno = %d\n", errno); 175 exit(1); 176 } 177 } 178 } 179 if(!ptrace_faultinfo && (stack != NULL)){ 180 unsigned long v = UML_CONFIG_STUB_CODE + 181 (unsigned long) stub_segv_handler - 182 (unsigned long) &__syscall_stub_start; 183 184 set_sigstack((void *) UML_CONFIG_STUB_DATA, page_size()); 185 set_handler(SIGSEGV, (void *) v, SA_ONSTACK, 186 SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, 187 SIGUSR1, -1); 188 } 189 190 os_stop_process(os_getpid()); 191 return(0); 192 } 193 194 /* Each element set once, and only accessed by a single processor anyway */ 195 #undef NR_CPUS 196 #define NR_CPUS 1 197 int userspace_pid[NR_CPUS]; 198 199 int start_userspace(unsigned long stub_stack) 200 { 201 void *stack; 202 unsigned long sp; 203 int pid, status, n, flags; 204 205 stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC, 206 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); 207 if(stack == MAP_FAILED) 208 panic("start_userspace : mmap failed, errno = %d", errno); 209 sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *); 210 211 flags = CLONE_FILES | SIGCHLD; 212 if(proc_mm) flags |= CLONE_VM; 213 pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack); 214 if(pid < 0) 215 panic("start_userspace : clone failed, errno = %d", errno); 216 217 do { 218 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); 219 if(n < 0) 220 panic("start_userspace : wait failed, errno = %d", 221 errno); 222 } while(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM)); 223 224 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) 225 panic("start_userspace : expected SIGSTOP, got status = %d", 226 status); 227 228 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, (void *)PTRACE_O_TRACESYSGOOD) < 0) 229 panic("start_userspace : PTRACE_SETOPTIONS failed, errno=%d\n", 230 errno); 231 232 if(munmap(stack, PAGE_SIZE) < 0) 233 panic("start_userspace : munmap failed, errno = %d\n", errno); 234 235 return(pid); 236 } 237 238 void userspace(union uml_pt_regs *regs) 239 { 240 int err, status, op, pid = userspace_pid[0]; 241 int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/ 242 243 while(1){ 244 restore_registers(pid, regs); 245 246 /* Now we set local_using_sysemu to be used for one loop */ 247 local_using_sysemu = get_using_sysemu(); 248 249 op = SELECT_PTRACE_OPERATION(local_using_sysemu, singlestepping(NULL)); 250 251 err = ptrace(op, pid, 0, 0); 252 if(err) 253 panic("userspace - could not resume userspace process, " 254 "pid=%d, ptrace operation = %d, errno = %d\n", 255 op, errno); 256 257 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED)); 258 if(err < 0) 259 panic("userspace - waitpid failed, errno = %d\n", 260 errno); 261 262 regs->skas.is_user = 1; 263 save_registers(pid, regs); 264 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */ 265 266 if(WIFSTOPPED(status)){ 267 switch(WSTOPSIG(status)){ 268 case SIGSEGV: 269 if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo) 270 user_signal(SIGSEGV, regs, pid); 271 else handle_segv(pid, regs); 272 break; 273 case SIGTRAP + 0x80: 274 handle_trap(pid, regs, local_using_sysemu); 275 break; 276 case SIGTRAP: 277 relay_signal(SIGTRAP, regs); 278 break; 279 case SIGIO: 280 case SIGVTALRM: 281 case SIGILL: 282 case SIGBUS: 283 case SIGFPE: 284 case SIGWINCH: 285 user_signal(WSTOPSIG(status), regs, pid); 286 break; 287 default: 288 printk("userspace - child stopped with signal " 289 "%d\n", WSTOPSIG(status)); 290 } 291 pid = userspace_pid[0]; 292 interrupt_end(); 293 294 /* Avoid -ERESTARTSYS handling in host */ 295 PT_SYSCALL_NR(regs->skas.regs) = -1; 296 } 297 } 298 } 299 #define INIT_JMP_NEW_THREAD 0 300 #define INIT_JMP_REMOVE_SIGSTACK 1 301 #define INIT_JMP_CALLBACK 2 302 #define INIT_JMP_HALT 3 303 #define INIT_JMP_REBOOT 4 304 305 306 int copy_context_skas0(unsigned long new_stack, int pid) 307 { 308 int err; 309 unsigned long regs[MAX_REG_NR]; 310 unsigned long current_stack = current_stub_stack(); 311 struct stub_data *data = (struct stub_data *) current_stack; 312 struct stub_data *child_data = (struct stub_data *) new_stack; 313 __u64 new_offset; 314 int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset); 315 316 /* prepare offset and fd of child's stack as argument for parent's 317 * and child's mmap2 calls 318 */ 319 *data = ((struct stub_data) { .offset = MMAP_OFFSET(new_offset), 320 .fd = new_fd, 321 .timer = ((struct itimerval) 322 { { 0, 1000000 / hz() }, 323 { 0, 1000000 / hz() }})}); 324 get_safe_registers(regs); 325 326 /* Set parent's instruction pointer to start of clone-stub */ 327 regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE + 328 (unsigned long) stub_clone_handler - 329 (unsigned long) &__syscall_stub_start; 330 regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE - 331 sizeof(void *); 332 err = ptrace_setregs(pid, regs); 333 if(err < 0) 334 panic("copy_context_skas0 : PTRACE_SETREGS failed, " 335 "pid = %d, errno = %d\n", pid, errno); 336 337 /* set a well known return code for detection of child write failure */ 338 child_data->err = 12345678; 339 340 /* Wait, until parent has finished its work: read child's pid from 341 * parent's stack, and check, if bad result. 342 */ 343 wait_stub_done(pid, 0, "copy_context_skas0"); 344 345 pid = data->err; 346 if(pid < 0) 347 panic("copy_context_skas0 - stub-parent reports error %d\n", 348 pid); 349 350 /* Wait, until child has finished too: read child's result from 351 * child's stack and check it. 352 */ 353 wait_stub_done(pid, -1, "copy_context_skas0"); 354 if (child_data->err != UML_CONFIG_STUB_DATA) 355 panic("copy_context_skas0 - stub-child reports error %d\n", 356 child_data->err); 357 358 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, 359 (void *)PTRACE_O_TRACESYSGOOD) < 0) 360 panic("copy_context_skas0 : PTRACE_SETOPTIONS failed, " 361 "errno = %d\n", errno); 362 363 return pid; 364 } 365 366 void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr, 367 void (*handler)(int)) 368 { 369 unsigned long flags; 370 sigjmp_buf switch_buf, fork_buf; 371 372 *switch_buf_ptr = &switch_buf; 373 *fork_buf_ptr = &fork_buf; 374 375 /* Somewhat subtle - siglongjmp restores the signal mask before doing 376 * the longjmp. This means that when jumping from one stack to another 377 * when the target stack has interrupts enabled, an interrupt may occur 378 * on the source stack. This is bad when starting up a process because 379 * it's not supposed to get timer ticks until it has been scheduled. 380 * So, we disable interrupts around the sigsetjmp to ensure that 381 * they can't happen until we get back here where they are safe. 382 */ 383 flags = get_signals(); 384 block_signals(); 385 if(sigsetjmp(fork_buf, 1) == 0) 386 new_thread_proc(stack, handler); 387 388 remove_sigstack(); 389 390 set_signals(flags); 391 } 392 393 void thread_wait(void *sw, void *fb) 394 { 395 sigjmp_buf buf, **switch_buf = sw, *fork_buf; 396 397 *switch_buf = &buf; 398 fork_buf = fb; 399 if(sigsetjmp(buf, 1) == 0) 400 siglongjmp(*fork_buf, INIT_JMP_REMOVE_SIGSTACK); 401 } 402 403 void switch_threads(void *me, void *next) 404 { 405 sigjmp_buf my_buf, **me_ptr = me, *next_buf = next; 406 407 *me_ptr = &my_buf; 408 if(sigsetjmp(my_buf, 1) == 0) 409 siglongjmp(*next_buf, 1); 410 } 411 412 static sigjmp_buf initial_jmpbuf; 413 414 /* XXX Make these percpu */ 415 static void (*cb_proc)(void *arg); 416 static void *cb_arg; 417 static sigjmp_buf *cb_back; 418 419 int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr) 420 { 421 sigjmp_buf **switch_buf = switch_buf_ptr; 422 int n; 423 424 set_handler(SIGWINCH, (__sighandler_t) sig_handler, 425 SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM, 426 SIGVTALRM, -1); 427 428 *fork_buf_ptr = &initial_jmpbuf; 429 n = sigsetjmp(initial_jmpbuf, 1); 430 switch(n){ 431 case INIT_JMP_NEW_THREAD: 432 new_thread_proc((void *) stack, new_thread_handler); 433 break; 434 case INIT_JMP_REMOVE_SIGSTACK: 435 remove_sigstack(); 436 break; 437 case INIT_JMP_CALLBACK: 438 (*cb_proc)(cb_arg); 439 siglongjmp(*cb_back, 1); 440 break; 441 case INIT_JMP_HALT: 442 kmalloc_ok = 0; 443 return(0); 444 case INIT_JMP_REBOOT: 445 kmalloc_ok = 0; 446 return(1); 447 default: 448 panic("Bad sigsetjmp return in start_idle_thread - %d\n", n); 449 } 450 siglongjmp(**switch_buf, 1); 451 } 452 453 void remove_sigstack(void) 454 { 455 stack_t stack = ((stack_t) { .ss_flags = SS_DISABLE, 456 .ss_sp = NULL, 457 .ss_size = 0 }); 458 459 if(sigaltstack(&stack, NULL) != 0) 460 panic("disabling signal stack failed, errno = %d\n", errno); 461 } 462 463 void initial_thread_cb_skas(void (*proc)(void *), void *arg) 464 { 465 sigjmp_buf here; 466 467 cb_proc = proc; 468 cb_arg = arg; 469 cb_back = &here; 470 471 block_signals(); 472 if(sigsetjmp(here, 1) == 0) 473 siglongjmp(initial_jmpbuf, INIT_JMP_CALLBACK); 474 unblock_signals(); 475 476 cb_proc = NULL; 477 cb_arg = NULL; 478 cb_back = NULL; 479 } 480 481 void halt_skas(void) 482 { 483 block_signals(); 484 siglongjmp(initial_jmpbuf, INIT_JMP_HALT); 485 } 486 487 void reboot_skas(void) 488 { 489 block_signals(); 490 siglongjmp(initial_jmpbuf, INIT_JMP_REBOOT); 491 } 492 493 void switch_mm_skas(struct mm_id *mm_idp) 494 { 495 int err; 496 497 #warning need cpu pid in switch_mm_skas 498 if(proc_mm){ 499 err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0, 500 mm_idp->u.mm_fd); 501 if(err) 502 panic("switch_mm_skas - PTRACE_SWITCH_MM failed, " 503 "errno = %d\n", errno); 504 } 505 else userspace_pid[0] = mm_idp->u.pid; 506 } 507 508 /* 509 * Overrides for Emacs so that we follow Linus's tabbing style. 510 * Emacs will notice this stuff at the end of the file and automatically 511 * adjust the settings for this buffer only. This must remain at the end 512 * of the file. 513 * --------------------------------------------------------------------------- 514 * Local variables: 515 * c-file-style: "linux" 516 * End: 517 */ 518