arch/ppc/kernel/signal.c

/* */
This source file includes following definitions.
sys_sigsuspend
sys_sigreturn
do_signal
   1 /*
   2  *  linux/arch/ppc/kernel/signal.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  *  Adapted for PowerPC by Gary Thomas
   6  */
   7 
   8 #include <linux/sched.h>
   9 #include <linux/mm.h>
  10 #include <linux/kernel.h>
  11 #include <linux/signal.h>
  12 #include <linux/errno.h>
  13 #include <linux/wait.h>
  14 #include <linux/ptrace.h>
  15 #include <linux/unistd.h>
  16 
  17 #define _S(nr) (1<<((nr)-1))
  18 
  19 #define _BLOCKABLE (~(_S(SIGKILL) | _S(SIGSTOP)))
  20 
  21 asmlinkage int sys_waitpid(pid_t pid,unsigned long * stat_addr, int options);
  22 
  23 /*
  24  * atomically swap in the new signal mask, and wait for a signal.
  25  */
  26 asmlinkage int sys_sigsuspend(unsigned long set, int p2, int p3, int p4, int p6, int p7, struct pt_regs *regs)
     /*  */
  27 {
  28         unsigned long mask;
  29 
  30         mask = current->blocked;
  31         current->blocked = set & _BLOCKABLE;
  32         regs->gpr[3] = -EINTR;
  33 #if 0   
  34 printk("Task: %x[%d] - SIGSUSPEND at %x, Mask: %x\n", current, current->pid, regs->nip, set);   
  35 #endif
  36         while (1) {
  37                 current->state = TASK_INTERRUPTIBLE;
  38                 schedule();
  39                 if (do_signal(mask,regs))
  40                         return -EINTR;
  41         }
  42 }
  43 
  44 /*
  45  * This sets regs->esp even though we don't actually use sigstacks yet..
  46  */
  47 asmlinkage int sys_sigreturn(struct pt_regs *regs)
     /*  */
  48 {
  49         struct sigcontext_struct *sc;
  50         struct pt_regs *int_regs;
  51         int signo;
  52         sc = (struct sigcontext_struct *)regs->gpr[1];
  53         current->blocked = sc->oldmask & _BLOCKABLE;
  54         int_regs = sc->regs;
  55         signo = sc->signal;
  56         sc++;  /* Pop signal 'context' */
  57         if (sc == (struct sigcontext_struct *)(int_regs))
  58         { /* Last stacked signal */
  59                 memcpy(regs, int_regs, sizeof(*regs));
  60                 if ((int)regs->orig_gpr3 >= 0 &&
  61                     ((int)regs->result == -ERESTARTNOHAND ||
  62                      (int)regs->result == -ERESTARTSYS ||
  63                      (int)regs->result == -ERESTARTNOINTR))
  64                 {
  65                         regs->gpr[3] = regs->orig_gpr3;
  66                         regs->nip -= 4; /* Back up & retry system call */
  67                         regs->result = 0;
  68                 }
  69                 return (regs->result);
  70         } else
  71         { /* More signals to go */
  72                 regs->gpr[1] = (unsigned long)sc;
  73                 regs->gpr[3] = sc->signal;
  74                 regs->gpr[4] = sc->regs;
  75                 regs->link = (unsigned long)((sc->regs)+1);
  76                 regs->nip = sc->handler;
  77                 return (sc->signal);
  78         }
  79 }
  80 
  81 
  82 /*
  83  * Note that 'init' is a special process: it doesn't get signals it doesn't
  84  * want to handle. Thus you cannot kill init even with a SIGKILL even by
  85  * mistake.
  86  *
  87  * Note that we go through the signals twice: once to check the signals that
  88  * the kernel can handle, and then we build all the user-level signal handling
  89  * stack-frames in one go after that.
  90  */
  91 asmlinkage int do_signal(unsigned long oldmask, struct pt_regs * regs)
     /*  */
  92 {
  93         unsigned long mask = ~current->blocked;
  94         unsigned long handler_signal = 0;
  95         unsigned long *frame = NULL;
  96         unsigned long *trampoline;
  97         unsigned long *regs_ptr;
  98         unsigned long nip = 0;
  99         unsigned long signr;
 100         int bitno;
 101         struct sigcontext_struct *sc;
 102         struct sigaction * sa;
 103         int s = _disable_interrupts();
 104 
 105         while ((signr = current->signal & mask)) {
 106 #if 0
 107                 signr = ffz(~signr);  /* Compute bit # */
 108 #else
 109                 for (bitno = 0;  bitno < 32;  bitno++)
 110                 {
 111                         if (signr & (1<<bitno)) break;
 112                 }
 113                 signr = bitno;
 114 #endif          
 115                 current->signal &= ~(1<<signr);  /* Clear bit */
 116                 sa = current->sig->action + signr;
 117                 signr++;
 118                 if ((current->flags & PF_PTRACED) && signr != SIGKILL) {
 119                         current->exit_code = signr;
 120                         current->state = TASK_STOPPED;
 121                         notify_parent(current);
 122                         schedule();
 123                         if (!(signr = current->exit_code))
 124                                 continue;
 125                         current->exit_code = 0;
 126                         if (signr == SIGSTOP)
 127                                 continue;
 128                         if (_S(signr) & current->blocked) {
 129                                 current->signal |= _S(signr);
 130                                 continue;
 131                         }
 132                         sa = current->sig->action + signr - 1;
 133                 }
 134                 if (sa->sa_handler == SIG_IGN) {
 135                         if (signr != SIGCHLD)
 136                                 continue;
 137                         /* check for SIGCHLD: it's special */
 138                         while (sys_waitpid(-1,NULL,WNOHANG) > 0)
 139                                 /* nothing */;
 140                         continue;
 141                 }
 142                 if (sa->sa_handler == SIG_DFL) {
 143                         if (current->pid == 1)
 144                                 continue;
 145                         switch (signr) {
 146                         case SIGCONT: case SIGCHLD: case SIGWINCH:
 147                                 continue;
 148 
 149                         case SIGSTOP: case SIGTSTP: case SIGTTIN: case SIGTTOU:
 150                                 if (current->flags & PF_PTRACED)
 151                                         continue;
 152                                 current->state = TASK_STOPPED;
 153                                 current->exit_code = signr;
 154                                 if (!(current->p_pptr->sig->action[SIGCHLD-1].sa_flags &
 155                                                 SA_NOCLDSTOP))
 156                                         notify_parent(current);
 157                                 schedule();
 158                                 continue;
 159 
 160                         case SIGQUIT: case SIGILL: case SIGTRAP:
 161                         case SIGIOT: case SIGFPE: case SIGSEGV:
 162                                 if (current->binfmt && current->binfmt->core_dump) {
 163                                         if (current->binfmt->core_dump(signr, regs))
 164                                                 signr |= 0x80;
 165                                 }
 166                                 /* fall through */
 167                         default:
 168                                 current->signal |= _S(signr & 0x7f);
 169                                 current->flags |= PF_SIGNALED;
 170                                 do_exit(signr);
 171                         }
 172                 }
 173                 /*
 174                  * OK, we're invoking a handler
 175                  */
 176                 if ((int)regs->orig_gpr3 >= 0) {
 177                         if ((int)regs->result == -ERESTARTNOHAND ||
 178                            ((int)regs->result == -ERESTARTSYS && !(sa->sa_flags & SA_RESTART)))
 179                                 (int)regs->result = -EINTR;
 180                 }
 181                 handler_signal |= 1 << (signr-1);
 182                 mask &= ~sa->sa_mask;
 183         }
 184         if (!handler_signal)            /* no handler will be called - return 0 */
 185         {
 186                 _enable_interrupts(s);
 187                 return 0;
 188         }
 189         nip = regs->nip;
 190         frame = (unsigned long *) regs->gpr[1];
 191         /* Build trampoline code on stack */
 192         frame -= 2;
 193         trampoline = frame;
 194         trampoline[0] = 0x38007777;  /* li r0,0x7777 */
 195         trampoline[1] = 0x44000002;  /* sc           */
 196         frame -= sizeof(*regs) / sizeof(long);
 197         regs_ptr = frame;
 198         memcpy(regs_ptr, regs, sizeof(*regs));
 199         signr = 1;
 200         sa = current->sig->action;
 201         for (mask = 1 ; mask ; sa++,signr++,mask += mask) {
 202                 if (mask > handler_signal)
 203                         break;
 204                 if (!(mask & handler_signal))
 205                         continue;
 206                 frame -= sizeof(struct sigcontext_struct) / sizeof(long);
 207                 sc = (struct sigcontext_struct *)frame;
 208                 nip = (unsigned long) sa->sa_handler;
 209 #if 0 /* Old compiler */                
 210                 nip = *(unsigned long *)nip;
 211 #endif          
 212                 if (sa->sa_flags & SA_ONESHOT)
 213                         sa->sa_handler = NULL;
 214                 sc->handler = nip;
 215                 sc->oldmask = current->blocked;
 216                 sc->regs = (unsigned long)regs_ptr;
 217                 sc->signal = signr;
 218                 current->blocked |= sa->sa_mask;
 219                 regs->gpr[3] = signr;
 220                 regs->gpr[4] = (unsigned long)regs_ptr;
 221         }
 222         regs->link = (unsigned long)trampoline;
 223         regs->nip = nip;
 224         regs->gpr[1] = (unsigned long)sc;
 225         /* The DATA cache must be flushed here to insure coherency */
 226         /* between the DATA & INSTRUCTION caches.  Since we just */
 227         /* created an instruction stream using the DATA [cache] space */
 228         /* and since the instruction cache will not look in the DATA */
 229         /* cache for new data, we have to force the data to go on to */
 230         /* memory and flush the instruction cache to force it to look */
 231         /* there.  The following function performs this magic */
 232         flush_instruction_cache();
 233         _enable_interrupts(s);
 234         return 1;
 235 }
/* */
root/arch/ppc/kernel/signal.c

DEFINITIONS
