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 66 if((n < 0) || !WIFSTOPPED(status) || 67 (WSTOPSIG(status) != SIGUSR1 && WSTOPSIG(status != SIGTRAP))){ 68 panic("%s : failed to wait for SIGUSR1/SIGTRAP, " 69 "pid = %d, n = %d, errno = %d, status = 0x%x\n", 70 fname, pid, n, errno, status); 71 } 72 } 73 74 void get_skas_faultinfo(int pid, struct faultinfo * fi) 75 { 76 int err; 77 78 if(ptrace_faultinfo){ 79 err = ptrace(PTRACE_FAULTINFO, pid, 0, fi); 80 if(err) 81 panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, " 82 "errno = %d\n", errno); 83 84 /* Special handling for i386, which has different structs */ 85 if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo)) 86 memset((char *)fi + sizeof(struct ptrace_faultinfo), 0, 87 sizeof(struct faultinfo) - 88 sizeof(struct ptrace_faultinfo)); 89 } 90 else { 91 wait_stub_done(pid, SIGSEGV, "get_skas_faultinfo"); 92 93 /* faultinfo is prepared by the stub-segv-handler at start of 94 * the stub stack page. We just have to copy it. 95 */ 96 memcpy(fi, (void *)current_stub_stack(), sizeof(*fi)); 97 } 98 } 99 100 static void handle_segv(int pid, union uml_pt_regs * regs) 101 { 102 get_skas_faultinfo(pid, ®s->skas.faultinfo); 103 segv(regs->skas.faultinfo, 0, 1, NULL); 104 } 105 106 /*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/ 107 static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu) 108 { 109 int err, status; 110 111 /* Mark this as a syscall */ 112 UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->skas.regs); 113 114 if (!local_using_sysemu) 115 { 116 err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET, __NR_getpid); 117 if(err < 0) 118 panic("handle_trap - nullifying syscall failed errno = %d\n", 119 errno); 120 121 err = ptrace(PTRACE_SYSCALL, pid, 0, 0); 122 if(err < 0) 123 panic("handle_trap - continuing to end of syscall failed, " 124 "errno = %d\n", errno); 125 126 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED)); 127 if((err < 0) || !WIFSTOPPED(status) || 128 (WSTOPSIG(status) != SIGTRAP + 0x80)) 129 panic("handle_trap - failed to wait at end of syscall, " 130 "errno = %d, status = %d\n", errno, status); 131 } 132 133 handle_syscall(regs); 134 } 135 136 extern int __syscall_stub_start; 137 138 static int userspace_tramp(void *stack) 139 { 140 void *addr; 141 142 ptrace(PTRACE_TRACEME, 0, 0, 0); 143 144 init_new_thread_signals(1); 145 enable_timer(); 146 147 if(!proc_mm){ 148 /* This has a pte, but it can't be mapped in with the usual 149 * tlb_flush mechanism because this is part of that mechanism 150 */ 151 int fd; 152 __u64 offset; 153 154 fd = phys_mapping(to_phys(&__syscall_stub_start), &offset); 155 addr = mmap64((void *) UML_CONFIG_STUB_CODE, page_size(), 156 PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset); 157 if(addr == MAP_FAILED){ 158 printk("mapping mmap stub failed, errno = %d\n", 159 errno); 160 exit(1); 161 } 162 163 if(stack != NULL){ 164 fd = phys_mapping(to_phys(stack), &offset); 165 addr = mmap((void *) UML_CONFIG_STUB_DATA, page_size(), 166 PROT_READ | PROT_WRITE, 167 MAP_FIXED | MAP_SHARED, fd, offset); 168 if(addr == MAP_FAILED){ 169 printk("mapping segfault stack failed, " 170 "errno = %d\n", errno); 171 exit(1); 172 } 173 } 174 } 175 if(!ptrace_faultinfo && (stack != NULL)){ 176 unsigned long v = UML_CONFIG_STUB_CODE + 177 (unsigned long) stub_segv_handler - 178 (unsigned long) &__syscall_stub_start; 179 180 set_sigstack((void *) UML_CONFIG_STUB_DATA, page_size()); 181 set_handler(SIGSEGV, (void *) v, SA_ONSTACK, 182 SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, 183 SIGUSR1, -1); 184 } 185 186 os_stop_process(os_getpid()); 187 return(0); 188 } 189 190 /* Each element set once, and only accessed by a single processor anyway */ 191 #undef NR_CPUS 192 #define NR_CPUS 1 193 int userspace_pid[NR_CPUS]; 194 195 int start_userspace(unsigned long stub_stack) 196 { 197 void *stack; 198 unsigned long sp; 199 int pid, status, n, flags; 200 201 stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC, 202 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); 203 if(stack == MAP_FAILED) 204 panic("start_userspace : mmap failed, errno = %d", errno); 205 sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *); 206 207 flags = CLONE_FILES | SIGCHLD; 208 if(proc_mm) flags |= CLONE_VM; 209 pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack); 210 if(pid < 0) 211 panic("start_userspace : clone failed, errno = %d", errno); 212 213 do { 214 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); 215 if(n < 0) 216 panic("start_userspace : wait failed, errno = %d", 217 errno); 218 } while(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM)); 219 220 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) 221 panic("start_userspace : expected SIGSTOP, got status = %d", 222 status); 223 224 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, (void *)PTRACE_O_TRACESYSGOOD) < 0) 225 panic("start_userspace : PTRACE_SETOPTIONS failed, errno=%d\n", 226 errno); 227 228 if(munmap(stack, PAGE_SIZE) < 0) 229 panic("start_userspace : munmap failed, errno = %d\n", errno); 230 231 return(pid); 232 } 233 234 void userspace(union uml_pt_regs *regs) 235 { 236 int err, status, op, pid = userspace_pid[0]; 237 int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/ 238 239 while(1){ 240 restore_registers(pid, regs); 241 242 /* Now we set local_using_sysemu to be used for one loop */ 243 local_using_sysemu = get_using_sysemu(); 244 245 op = SELECT_PTRACE_OPERATION(local_using_sysemu, singlestepping(NULL)); 246 247 err = ptrace(op, pid, 0, 0); 248 if(err) 249 panic("userspace - could not resume userspace process, " 250 "pid=%d, ptrace operation = %d, errno = %d\n", 251 op, errno); 252 253 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED)); 254 if(err < 0) 255 panic("userspace - waitpid failed, errno = %d\n", 256 errno); 257 258 regs->skas.is_user = 1; 259 save_registers(pid, regs); 260 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */ 261 262 if(WIFSTOPPED(status)){ 263 switch(WSTOPSIG(status)){ 264 case SIGSEGV: 265 if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo) 266 user_signal(SIGSEGV, regs, pid); 267 else handle_segv(pid, regs); 268 break; 269 case SIGTRAP + 0x80: 270 handle_trap(pid, regs, local_using_sysemu); 271 break; 272 case SIGTRAP: 273 relay_signal(SIGTRAP, regs); 274 break; 275 case SIGIO: 276 case SIGVTALRM: 277 case SIGILL: 278 case SIGBUS: 279 case SIGFPE: 280 case SIGWINCH: 281 user_signal(WSTOPSIG(status), regs, pid); 282 break; 283 default: 284 printk("userspace - child stopped with signal " 285 "%d\n", WSTOPSIG(status)); 286 } 287 pid = userspace_pid[0]; 288 interrupt_end(); 289 290 /* Avoid -ERESTARTSYS handling in host */ 291 PT_SYSCALL_NR(regs->skas.regs) = -1; 292 } 293 } 294 } 295 #define INIT_JMP_NEW_THREAD 0 296 #define INIT_JMP_REMOVE_SIGSTACK 1 297 #define INIT_JMP_CALLBACK 2 298 #define INIT_JMP_HALT 3 299 #define INIT_JMP_REBOOT 4 300 301 302 int copy_context_skas0(unsigned long new_stack, int pid) 303 { 304 int err; 305 unsigned long regs[MAX_REG_NR]; 306 unsigned long current_stack = current_stub_stack(); 307 struct stub_data *data = (struct stub_data *) current_stack; 308 struct stub_data *child_data = (struct stub_data *) new_stack; 309 __u64 new_offset; 310 int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset); 311 312 /* prepare offset and fd of child's stack as argument for parent's 313 * and child's mmap2 calls 314 */ 315 *data = ((struct stub_data) { .offset = MMAP_OFFSET(new_offset), 316 .fd = new_fd, 317 .timer = ((struct itimerval) 318 { { 0, 1000000 / hz() }, 319 { 0, 1000000 / hz() }})}); 320 get_safe_registers(regs); 321 322 /* Set parent's instruction pointer to start of clone-stub */ 323 regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE + 324 (unsigned long) stub_clone_handler - 325 (unsigned long) &__syscall_stub_start; 326 regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE - 327 sizeof(void *); 328 err = ptrace_setregs(pid, regs); 329 if(err < 0) 330 panic("copy_context_skas0 : PTRACE_SETREGS failed, " 331 "pid = %d, errno = %d\n", pid, errno); 332 333 /* set a well known return code for detection of child write failure */ 334 child_data->err = 12345678; 335 336 /* Wait, until parent has finished its work: read child's pid from 337 * parent's stack, and check, if bad result. 338 */ 339 wait_stub_done(pid, 0, "copy_context_skas0"); 340 341 pid = data->err; 342 if(pid < 0) 343 panic("copy_context_skas0 - stub-parent reports error %d\n", 344 pid); 345 346 /* Wait, until child has finished too: read child's result from 347 * child's stack and check it. 348 */ 349 wait_stub_done(pid, -1, "copy_context_skas0"); 350 if (child_data->err != UML_CONFIG_STUB_DATA) 351 panic("copy_context_skas0 - stub-child reports error %d\n", 352 child_data->err); 353 354 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, 355 (void *)PTRACE_O_TRACESYSGOOD) < 0) 356 panic("copy_context_skas0 : PTRACE_SETOPTIONS failed, " 357 "errno = %d\n", errno); 358 359 return pid; 360 } 361 362 void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr, 363 void (*handler)(int)) 364 { 365 unsigned long flags; 366 sigjmp_buf switch_buf, fork_buf; 367 368 *switch_buf_ptr = &switch_buf; 369 *fork_buf_ptr = &fork_buf; 370 371 /* Somewhat subtle - siglongjmp restores the signal mask before doing 372 * the longjmp. This means that when jumping from one stack to another 373 * when the target stack has interrupts enabled, an interrupt may occur 374 * on the source stack. This is bad when starting up a process because 375 * it's not supposed to get timer ticks until it has been scheduled. 376 * So, we disable interrupts around the sigsetjmp to ensure that 377 * they can't happen until we get back here where they are safe. 378 */ 379 flags = get_signals(); 380 block_signals(); 381 if(sigsetjmp(fork_buf, 1) == 0) 382 new_thread_proc(stack, handler); 383 384 remove_sigstack(); 385 386 set_signals(flags); 387 } 388 389 void thread_wait(void *sw, void *fb) 390 { 391 sigjmp_buf buf, **switch_buf = sw, *fork_buf; 392 393 *switch_buf = &buf; 394 fork_buf = fb; 395 if(sigsetjmp(buf, 1) == 0) 396 siglongjmp(*fork_buf, INIT_JMP_REMOVE_SIGSTACK); 397 } 398 399 void switch_threads(void *me, void *next) 400 { 401 sigjmp_buf my_buf, **me_ptr = me, *next_buf = next; 402 403 *me_ptr = &my_buf; 404 if(sigsetjmp(my_buf, 1) == 0) 405 siglongjmp(*next_buf, 1); 406 } 407 408 static sigjmp_buf initial_jmpbuf; 409 410 /* XXX Make these percpu */ 411 static void (*cb_proc)(void *arg); 412 static void *cb_arg; 413 static sigjmp_buf *cb_back; 414 415 int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr) 416 { 417 sigjmp_buf **switch_buf = switch_buf_ptr; 418 int n; 419 420 set_handler(SIGWINCH, (__sighandler_t) sig_handler, 421 SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM, 422 SIGVTALRM, -1); 423 424 *fork_buf_ptr = &initial_jmpbuf; 425 n = sigsetjmp(initial_jmpbuf, 1); 426 switch(n){ 427 case INIT_JMP_NEW_THREAD: 428 new_thread_proc((void *) stack, new_thread_handler); 429 break; 430 case INIT_JMP_REMOVE_SIGSTACK: 431 remove_sigstack(); 432 break; 433 case INIT_JMP_CALLBACK: 434 (*cb_proc)(cb_arg); 435 siglongjmp(*cb_back, 1); 436 break; 437 case INIT_JMP_HALT: 438 kmalloc_ok = 0; 439 return(0); 440 case INIT_JMP_REBOOT: 441 kmalloc_ok = 0; 442 return(1); 443 default: 444 panic("Bad sigsetjmp return in start_idle_thread - %d\n", n); 445 } 446 siglongjmp(**switch_buf, 1); 447 } 448 449 void remove_sigstack(void) 450 { 451 stack_t stack = ((stack_t) { .ss_flags = SS_DISABLE, 452 .ss_sp = NULL, 453 .ss_size = 0 }); 454 455 if(sigaltstack(&stack, NULL) != 0) 456 panic("disabling signal stack failed, errno = %d\n", errno); 457 } 458 459 void initial_thread_cb_skas(void (*proc)(void *), void *arg) 460 { 461 sigjmp_buf here; 462 463 cb_proc = proc; 464 cb_arg = arg; 465 cb_back = &here; 466 467 block_signals(); 468 if(sigsetjmp(here, 1) == 0) 469 siglongjmp(initial_jmpbuf, INIT_JMP_CALLBACK); 470 unblock_signals(); 471 472 cb_proc = NULL; 473 cb_arg = NULL; 474 cb_back = NULL; 475 } 476 477 void halt_skas(void) 478 { 479 block_signals(); 480 siglongjmp(initial_jmpbuf, INIT_JMP_HALT); 481 } 482 483 void reboot_skas(void) 484 { 485 block_signals(); 486 siglongjmp(initial_jmpbuf, INIT_JMP_REBOOT); 487 } 488 489 void switch_mm_skas(struct mm_id *mm_idp) 490 { 491 int err; 492 493 #warning need cpu pid in switch_mm_skas 494 if(proc_mm){ 495 err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0, 496 mm_idp->u.mm_fd); 497 if(err) 498 panic("switch_mm_skas - PTRACE_SWITCH_MM failed, " 499 "errno = %d\n", errno); 500 } 501 else userspace_pid[0] = mm_idp->u.pid; 502 } 503 504 /* 505 * Overrides for Emacs so that we follow Linus's tabbing style. 506 * Emacs will notice this stuff at the end of the file and automatically 507 * adjust the settings for this buffer only. This must remain at the end 508 * of the file. 509 * --------------------------------------------------------------------------- 510 * Local variables: 511 * c-file-style: "linux" 512 * End: 513 */ 514