git.oblomov.eu Git - linux-2.6/blob - arch/um/kernel/skas/process.c

   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, &regs->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  */