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 <asm/unistd.h> 17 #include <asm/types.h> 18 #include "user.h" 19 #include "ptrace_user.h" 20 #include "time_user.h" 21 #include "sysdep/ptrace.h" 22 #include "user_util.h" 23 #include "kern_util.h" 24 #include "skas.h" 25 #include "mm_id.h" 26 #include "sysdep/sigcontext.h" 27 #include "sysdep/stub.h" 28 #include "os.h" 29 #include "proc_mm.h" 30 #include "skas_ptrace.h" 31 #include "chan_user.h" 32 #include "signal_user.h" 33 #include "registers.h" 34 #include "mem.h" 35 #include "uml-config.h" 36 #include "process.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 void wait_stub_done(int pid, int sig, char * fname) 48 { 49 int n, status, err; 50 51 do { 52 if ( sig != -1 ) { 53 err = ptrace(PTRACE_CONT, pid, 0, sig); 54 if(err) 55 panic("%s : continue failed, errno = %d\n", 56 fname, errno); 57 } 58 sig = 0; 59 60 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); 61 } while((n >= 0) && WIFSTOPPED(status) && 62 (WSTOPSIG(status) == SIGVTALRM)); 63 64 if((n < 0) || !WIFSTOPPED(status) || 65 (WSTOPSIG(status) != SIGUSR1 && WSTOPSIG(status != SIGTRAP))){ 66 panic("%s : failed to wait for SIGUSR1/SIGTRAP, " 67 "pid = %d, n = %d, errno = %d, status = 0x%x\n", 68 fname, pid, n, errno, status); 69 } 70 } 71 72 void get_skas_faultinfo(int pid, struct faultinfo * fi) 73 { 74 int err; 75 76 if(ptrace_faultinfo){ 77 err = ptrace(PTRACE_FAULTINFO, pid, 0, fi); 78 if(err) 79 panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, " 80 "errno = %d\n", errno); 81 82 /* Special handling for i386, which has different structs */ 83 if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo)) 84 memset((char *)fi + sizeof(struct ptrace_faultinfo), 0, 85 sizeof(struct faultinfo) - 86 sizeof(struct ptrace_faultinfo)); 87 } 88 else { 89 wait_stub_done(pid, SIGSEGV, "get_skas_faultinfo"); 90 91 /* faultinfo is prepared by the stub-segv-handler at start of 92 * the stub stack page. We just have to copy it. 93 */ 94 memcpy(fi, (void *)current_stub_stack(), sizeof(*fi)); 95 } 96 } 97 98 static void handle_segv(int pid, union uml_pt_regs * regs) 99 { 100 get_skas_faultinfo(pid, ®s->skas.faultinfo); 101 segv(regs->skas.faultinfo, 0, 1, NULL); 102 } 103 104 /*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/ 105 static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu) 106 { 107 int err, status; 108 109 /* Mark this as a syscall */ 110 UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->skas.regs); 111 112 if (!local_using_sysemu) 113 { 114 err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET, __NR_getpid); 115 if(err < 0) 116 panic("handle_trap - nullifying syscall failed errno = %d\n", 117 errno); 118 119 err = ptrace(PTRACE_SYSCALL, pid, 0, 0); 120 if(err < 0) 121 panic("handle_trap - continuing to end of syscall failed, " 122 "errno = %d\n", errno); 123 124 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED)); 125 if((err < 0) || !WIFSTOPPED(status) || 126 (WSTOPSIG(status) != SIGTRAP + 0x80)) 127 panic("handle_trap - failed to wait at end of syscall, " 128 "errno = %d, status = %d\n", errno, status); 129 } 130 131 handle_syscall(regs); 132 } 133 134 extern int __syscall_stub_start; 135 136 static int userspace_tramp(void *stack) 137 { 138 void *addr; 139 140 ptrace(PTRACE_TRACEME, 0, 0, 0); 141 142 init_new_thread_signals(1); 143 enable_timer(); 144 145 if(!proc_mm){ 146 /* This has a pte, but it can't be mapped in with the usual 147 * tlb_flush mechanism because this is part of that mechanism 148 */ 149 int fd; 150 __u64 offset; 151 152 fd = phys_mapping(to_phys(&__syscall_stub_start), &offset); 153 addr = mmap64((void *) UML_CONFIG_STUB_CODE, page_size(), 154 PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset); 155 if(addr == MAP_FAILED){ 156 printk("mapping mmap stub failed, errno = %d\n", 157 errno); 158 exit(1); 159 } 160 161 if(stack != NULL){ 162 fd = phys_mapping(to_phys(stack), &offset); 163 addr = mmap((void *) UML_CONFIG_STUB_DATA, page_size(), 164 PROT_READ | PROT_WRITE, 165 MAP_FIXED | MAP_SHARED, fd, offset); 166 if(addr == MAP_FAILED){ 167 printk("mapping segfault stack failed, " 168 "errno = %d\n", errno); 169 exit(1); 170 } 171 } 172 } 173 if(!ptrace_faultinfo && (stack != NULL)){ 174 unsigned long v = UML_CONFIG_STUB_CODE + 175 (unsigned long) stub_segv_handler - 176 (unsigned long) &__syscall_stub_start; 177 178 set_sigstack((void *) UML_CONFIG_STUB_DATA, page_size()); 179 set_handler(SIGSEGV, (void *) v, SA_ONSTACK, 180 SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, 181 SIGUSR1, -1); 182 } 183 184 os_stop_process(os_getpid()); 185 return(0); 186 } 187 188 /* Each element set once, and only accessed by a single processor anyway */ 189 #undef NR_CPUS 190 #define NR_CPUS 1 191 int userspace_pid[NR_CPUS]; 192 193 int start_userspace(unsigned long stub_stack) 194 { 195 void *stack; 196 unsigned long sp; 197 int pid, status, n, flags; 198 199 stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC, 200 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); 201 if(stack == MAP_FAILED) 202 panic("start_userspace : mmap failed, errno = %d", errno); 203 sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *); 204 205 flags = CLONE_FILES | SIGCHLD; 206 if(proc_mm) flags |= CLONE_VM; 207 pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack); 208 if(pid < 0) 209 panic("start_userspace : clone failed, errno = %d", errno); 210 211 do { 212 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); 213 if(n < 0) 214 panic("start_userspace : wait failed, errno = %d", 215 errno); 216 } while(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM)); 217 218 if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) 219 panic("start_userspace : expected SIGSTOP, got status = %d", 220 status); 221 222 if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, (void *)PTRACE_O_TRACESYSGOOD) < 0) 223 panic("start_userspace : PTRACE_SETOPTIONS failed, errno=%d\n", 224 errno); 225 226 if(munmap(stack, PAGE_SIZE) < 0) 227 panic("start_userspace : munmap failed, errno = %d\n", errno); 228 229 return(pid); 230 } 231 232 void userspace(union uml_pt_regs *regs) 233 { 234 int err, status, op, pid = userspace_pid[0]; 235 int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/ 236 237 while(1){ 238 restore_registers(pid, regs); 239 240 /* Now we set local_using_sysemu to be used for one loop */ 241 local_using_sysemu = get_using_sysemu(); 242 243 op = SELECT_PTRACE_OPERATION(local_using_sysemu, singlestepping(NULL)); 244 245 err = ptrace(op, pid, 0, 0); 246 if(err) 247 panic("userspace - could not resume userspace process, " 248 "pid=%d, ptrace operation = %d, errno = %d\n", 249 op, errno); 250 251 CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED)); 252 if(err < 0) 253 panic("userspace - waitpid failed, errno = %d\n", 254 errno); 255 256 regs->skas.is_user = 1; 257 save_registers(pid, regs); 258 UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */ 259 260 if(WIFSTOPPED(status)){ 261 switch(WSTOPSIG(status)){ 262 case SIGSEGV: 263 if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo) 264 user_signal(SIGSEGV, regs, pid); 265 else handle_segv(pid, regs); 266 break; 267 case SIGTRAP + 0x80: 268 handle_trap(pid, regs, local_using_sysemu); 269 break; 270 case SIGTRAP: 271 relay_signal(SIGTRAP, regs); 272 break; 273 case SIGIO: 274 case SIGVTALRM: 275 case SIGILL: 276 case SIGBUS: 277 case SIGFPE: 278 case SIGWINCH: 279 user_signal(WSTOPSIG(status), regs, pid); 280 break; 281 default: 282 printk("userspace - child stopped with signal " 283 "%d\n", WSTOPSIG(status)); 284 } 285 pid = userspace_pid[0]; 286 interrupt_end(); 287 288 /* Avoid -ERESTARTSYS handling in host */ 289 PT_SYSCALL_NR(regs->skas.regs) = -1; 290 } 291 } 292 } 293 #define INIT_JMP_NEW_THREAD 0 294 #define INIT_JMP_REMOVE_SIGSTACK 1 295 #define INIT_JMP_CALLBACK 2 296 #define INIT_JMP_HALT 3 297 #define INIT_JMP_REBOOT 4 298 299 void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr, 300 void (*handler)(int)) 301 { 302 unsigned long flags; 303 sigjmp_buf switch_buf, fork_buf; 304 305 *switch_buf_ptr = &switch_buf; 306 *fork_buf_ptr = &fork_buf; 307 308 /* Somewhat subtle - siglongjmp restores the signal mask before doing 309 * the longjmp. This means that when jumping from one stack to another 310 * when the target stack has interrupts enabled, an interrupt may occur 311 * on the source stack. This is bad when starting up a process because 312 * it's not supposed to get timer ticks until it has been scheduled. 313 * So, we disable interrupts around the sigsetjmp to ensure that 314 * they can't happen until we get back here where they are safe. 315 */ 316 flags = get_signals(); 317 block_signals(); 318 if(sigsetjmp(fork_buf, 1) == 0) 319 new_thread_proc(stack, handler); 320 321 remove_sigstack(); 322 323 set_signals(flags); 324 } 325 326 void thread_wait(void *sw, void *fb) 327 { 328 sigjmp_buf buf, **switch_buf = sw, *fork_buf; 329 330 *switch_buf = &buf; 331 fork_buf = fb; 332 if(sigsetjmp(buf, 1) == 0) 333 siglongjmp(*fork_buf, INIT_JMP_REMOVE_SIGSTACK); 334 } 335 336 void switch_threads(void *me, void *next) 337 { 338 sigjmp_buf my_buf, **me_ptr = me, *next_buf = next; 339 340 *me_ptr = &my_buf; 341 if(sigsetjmp(my_buf, 1) == 0) 342 siglongjmp(*next_buf, 1); 343 } 344 345 static sigjmp_buf initial_jmpbuf; 346 347 /* XXX Make these percpu */ 348 static void (*cb_proc)(void *arg); 349 static void *cb_arg; 350 static sigjmp_buf *cb_back; 351 352 int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr) 353 { 354 sigjmp_buf **switch_buf = switch_buf_ptr; 355 int n; 356 357 set_handler(SIGWINCH, (__sighandler_t) sig_handler, 358 SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM, 359 SIGVTALRM, -1); 360 361 *fork_buf_ptr = &initial_jmpbuf; 362 n = sigsetjmp(initial_jmpbuf, 1); 363 switch(n){ 364 case INIT_JMP_NEW_THREAD: 365 new_thread_proc((void *) stack, new_thread_handler); 366 break; 367 case INIT_JMP_REMOVE_SIGSTACK: 368 remove_sigstack(); 369 break; 370 case INIT_JMP_CALLBACK: 371 (*cb_proc)(cb_arg); 372 siglongjmp(*cb_back, 1); 373 break; 374 case INIT_JMP_HALT: 375 kmalloc_ok = 0; 376 return(0); 377 case INIT_JMP_REBOOT: 378 kmalloc_ok = 0; 379 return(1); 380 default: 381 panic("Bad sigsetjmp return in start_idle_thread - %d\n", n); 382 } 383 siglongjmp(**switch_buf, 1); 384 } 385 386 void remove_sigstack(void) 387 { 388 stack_t stack = ((stack_t) { .ss_flags = SS_DISABLE, 389 .ss_sp = NULL, 390 .ss_size = 0 }); 391 392 if(sigaltstack(&stack, NULL) != 0) 393 panic("disabling signal stack failed, errno = %d\n", errno); 394 } 395 396 void initial_thread_cb_skas(void (*proc)(void *), void *arg) 397 { 398 sigjmp_buf here; 399 400 cb_proc = proc; 401 cb_arg = arg; 402 cb_back = &here; 403 404 block_signals(); 405 if(sigsetjmp(here, 1) == 0) 406 siglongjmp(initial_jmpbuf, INIT_JMP_CALLBACK); 407 unblock_signals(); 408 409 cb_proc = NULL; 410 cb_arg = NULL; 411 cb_back = NULL; 412 } 413 414 void halt_skas(void) 415 { 416 block_signals(); 417 siglongjmp(initial_jmpbuf, INIT_JMP_HALT); 418 } 419 420 void reboot_skas(void) 421 { 422 block_signals(); 423 siglongjmp(initial_jmpbuf, INIT_JMP_REBOOT); 424 } 425 426 void switch_mm_skas(struct mm_id *mm_idp) 427 { 428 int err; 429 430 #warning need cpu pid in switch_mm_skas 431 if(proc_mm){ 432 err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0, 433 mm_idp->u.mm_fd); 434 if(err) 435 panic("switch_mm_skas - PTRACE_SWITCH_MM failed, " 436 "errno = %d\n", errno); 437 } 438 else userspace_pid[0] = mm_idp->u.pid; 439 } 440 441 /* 442 * Overrides for Emacs so that we follow Linus's tabbing style. 443 * Emacs will notice this stuff at the end of the file and automatically 444 * adjust the settings for this buffer only. This must remain at the end 445 * of the file. 446 * --------------------------------------------------------------------------- 447 * Local variables: 448 * c-file-style: "linux" 449 * End: 450 */ 451