/*
* linux/arch/ppc/kernel/signal.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Adapted for PowerPC by Gary Thomas
*/
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#define _S(nr) (1<<((nr)-1))
#define _BLOCKABLE (~(_S(SIGKILL) | _S(SIGSTOP)))
asmlinkage int sys_waitpid(pid_t pid,unsigned long * stat_addr, int options);
/*
* atomically swap in the new signal mask, and wait for a signal.
*/
asmlinkage int sys_sigsuspend(unsigned long set, int p2, int p3, int p4, int p6, int p7, struct pt_regs *regs)
{
unsigned long mask;
mask = current->blocked;
current->blocked = set & _BLOCKABLE;
regs->gpr[3] = -EINTR;
#if 0
printk("Task: %x[%d] - SIGSUSPEND at %x, Mask: %x\n", current, current->pid, regs->nip, set);
#endif
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(mask,regs))
return -EINTR;
}
}
/*
* This sets regs->esp even though we don't actually use sigstacks yet..
*/
asmlinkage int sys_sigreturn(struct pt_regs *regs)
{
struct sigcontext_struct *sc;
struct pt_regs *int_regs;
int signo;
sc = (struct sigcontext_struct *)regs->gpr[1];
current->blocked = sc->oldmask & _BLOCKABLE;
int_regs = sc->regs;
signo = sc->signal;
sc++; /* Pop signal 'context' */
if (sc == (struct sigcontext_struct *)(int_regs))
{ /* Last stacked signal */
#if 0
/* This doesn't work - it blows away the return address! */
memcpy(regs, int_regs, sizeof(*regs));
#else
/* Don't mess up 'my' stack frame */
memcpy(®s->gpr, &int_regs->gpr, sizeof(*regs)-sizeof(regs->_overhead));
#endif
if ((int)regs->orig_gpr3 >= 0 &&
((int)regs->result == -ERESTARTNOHAND ||
(int)regs->result == -ERESTARTSYS ||
(int)regs->result == -ERESTARTNOINTR))
{
regs->gpr[3] = regs->orig_gpr3;
regs->nip -= 4; /* Back up & retry system call */
regs->result = 0;
}
return (regs->result);
} else
{ /* More signals to go */
regs->gpr[1] = (unsigned long)sc;
regs->gpr[3] = sc->signal;
regs->gpr[4] = sc->regs;
regs->link = (unsigned long)((sc->regs)+1);
regs->nip = sc->handler;
return (sc->signal);
}
}
/*
* Note that 'init' is a special process: it doesn't get signals it doesn't
* want to handle. Thus you cannot kill init even with a SIGKILL even by
* mistake.
*
* Note that we go through the signals twice: once to check the signals that
* the kernel can handle, and then we build all the user-level signal handling
* stack-frames in one go after that.
*/
asmlinkage int do_signal(unsigned long oldmask, struct pt_regs * regs)
{
unsigned long mask = ~current->blocked;
unsigned long handler_signal = 0;
unsigned long *frame = NULL;
unsigned long *trampoline;
unsigned long *regs_ptr;
unsigned long nip = 0;
unsigned long signr;
int bitno;
struct sigcontext_struct *sc;
struct sigaction * sa;
int s = _disable_interrupts();
while ((signr = current->signal & mask)) {
#if 0
signr = ffz(~signr); /* Compute bit # */
#else
for (bitno = 0; bitno < 32; bitno++)
{
if (signr & (1<<bitno)) break;
}
signr = bitno;
#endif
current->signal &= ~(1<<signr); /* Clear bit */
sa = current->sig->action + signr;
signr++;
if ((current->flags & PF_PTRACED) && signr != SIGKILL) {
current->exit_code = signr;
current->state = TASK_STOPPED;
notify_parent(current);
schedule();
if (!(signr = current->exit_code))
continue;
current->exit_code = 0;
if (signr == SIGSTOP)
continue;
if (_S(signr) & current->blocked) {
current->signal |= _S(signr);
continue;
}
sa = current->sig->action + signr - 1;
}
if (sa->sa_handler == SIG_IGN) {
if (signr != SIGCHLD)
continue;
/* check for SIGCHLD: it's special */
while (sys_waitpid(-1,NULL,WNOHANG) > 0)
/* nothing */;
continue;
}
if (sa->sa_handler == SIG_DFL) {
if (current->pid == 1)
continue;
switch (signr) {
case SIGCONT: case SIGCHLD: case SIGWINCH:
continue;
case SIGSTOP: case SIGTSTP: case SIGTTIN: case SIGTTOU:
if (current->flags & PF_PTRACED)
continue;
current->state = TASK_STOPPED;
current->exit_code = signr;
if (!(current->p_pptr->sig->action[SIGCHLD-1].sa_flags &
SA_NOCLDSTOP))
notify_parent(current);
schedule();
continue;
case SIGQUIT: case SIGILL: case SIGTRAP:
case SIGIOT: case SIGFPE: case SIGSEGV:
if (current->binfmt && current->binfmt->core_dump) {
if (current->binfmt->core_dump(signr, regs))
signr |= 0x80;
}
/* fall through */
default:
current->signal |= _S(signr & 0x7f);
do_exit(signr);
}
}
/*
* OK, we're invoking a handler
*/
if ((int)regs->orig_gpr3 >= 0) {
if ((int)regs->result == -ERESTARTNOHAND ||
((int)regs->result == -ERESTARTSYS && !(sa->sa_flags & SA_RESTART)))
(int)regs->result = -EINTR;
}
handler_signal |= 1 << (signr-1);
mask &= ~sa->sa_mask;
}
if (!handler_signal) /* no handler will be called - return 0 */
{
_enable_interrupts(s);
return 0;
}
nip = regs->nip;
frame = (unsigned long *) regs->gpr[1];
/* Build trampoline code on stack */
frame -= 2;
trampoline = frame;
trampoline[0] = 0x38007777; /* li r0,0x7777 */
trampoline[1] = 0x44000002; /* sc */
frame -= sizeof(*regs) / sizeof(long);
regs_ptr = frame;
memcpy(regs_ptr, regs, sizeof(*regs));
signr = 1;
sa = current->sig->action;
for (mask = 1 ; mask ; sa++,signr++,mask += mask) {
if (mask > handler_signal)
break;
if (!(mask & handler_signal))
continue;
frame -= sizeof(struct sigcontext_struct) / sizeof(long);
sc = (struct sigcontext_struct *)frame;
nip = (unsigned long) sa->sa_handler;
#if 0 /* Old compiler */
nip = *(unsigned long *)nip;
#endif
if (sa->sa_flags & SA_ONESHOT)
sa->sa_handler = NULL;
sc->handler = nip;
sc->oldmask = current->blocked;
sc->regs = (unsigned long)regs_ptr;
sc->signal = signr;
current->blocked |= sa->sa_mask;
regs->gpr[3] = signr;
regs->gpr[4] = (unsigned long)regs_ptr;
}
regs->link = (unsigned long)trampoline;
regs->nip = nip;
regs->gpr[1] = (unsigned long)sc;
/* The DATA cache must be flushed here to insure coherency */
/* between the DATA & INSTRUCTION caches. Since we just */
/* created an instruction stream using the DATA [cache] space */
/* and since the instruction cache will not look in the DATA */
/* cache for new data, we have to force the data to go on to */
/* memory and flush the instruction cache to force it to look */
/* there. The following function performs this magic */
flush_instruction_cache();
_enable_interrupts(s);
return 1;
}
