signal.c

microwindows移植到S3C44B0的源码

#ifndef CONFIG_UCLINUX
	if (fsize < 0) {
#ifdef DEBUG
		printk ("setup_frame: Unknown frame format %#x\n",
			regs->format);
#endif
		goto give_sigsegv;
	}

	frame = get_sigframe(ka, regs, sizeof(*frame) + fsize);

	if (fsize) {
		err |= copy_to_user (frame + 1, regs + 1, fsize);
		regs->stkadj = fsize;
	}
#else /* ! CONFIG_UCLINUX */
	frame = get_sigframe(ka, regs, sizeof(*frame));
#endif /* ! CONFIG_UCLINUX */

	err |= __put_user((current->exec_domain
			   && current->exec_domain->signal_invmap
			   && sig < 32
			   ? current->exec_domain->signal_invmap[sig]
			   : sig),
			  &frame->sig);

	err |= __put_user(regs->vector, &frame->code);
	err |= __put_user(&frame->sc, &frame->psc);

	if (_NSIG_WORDS > 1)
		err |= copy_to_user(frame->extramask, &set->sig[1],
				    sizeof(frame->extramask));

	setup_sigcontext(&context, regs, set->sig[0]);
	err |= copy_to_user (&frame->sc, &context, sizeof(context));

	/* Set up to return from userspace.  */
	err |= __put_user(frame->retcode, &frame->pretcode);

	/* movea.l #,a5; moveq #,d0; trap #0 */
	a5 = ((struct switch_stack *)regs - 1)->a5;
	err != __put_user(0x2a7c0000 + ((a5 >> 16) & 0xffff),
			(long *)(frame->retcode + 0));
	err != __put_user(0x00007000 + ((a5 & 0xffff) << 16) + __NR_sigreturn,
			(long *)(frame->retcode + 4));
	err |= __put_user(0x4e40, (short *)(frame->retcode + 8));


	if (err)
		goto give_sigsegv;

	push_cache ((unsigned long) &frame->retcode);

	/* Set up registers for signal handler */
	wrusp ((unsigned long) frame);
	regs->pc = (unsigned long) ka->sa.sa_handler;

adjust_stack:
	/* Prepare to skip over the extra stuff in the exception frame.  */
	if (regs->stkadj) {
		struct pt_regs *tregs =
			(struct pt_regs *)((ulong)regs + regs->stkadj);
#if DEBUG
		printk("Performing stackadjust=%04x\n", regs->stkadj);
#endif
		/* This must be copied with decreasing addresses to
                   handle overlaps.  */
		tregs->vector = 0;
		tregs->format = 0;
		tregs->pc = regs->pc;
		tregs->sr = regs->sr;
	}
	return;

give_sigsegv:
	if (sig == SIGSEGV)
		ka->sa.sa_handler = SIG_DFL;
	force_sig(SIGSEGV, current);
	goto adjust_stack;
}

static void setup_rt_frame (int sig, struct k_sigaction *ka, siginfo_t *info,
			    sigset_t *set, struct pt_regs *regs)
{
	struct rt_sigframe *frame;
	unsigned long a5;
#ifndef CONFIG_UCLINUX
	int fsize = frame_extra_sizes[regs->format];
#endif
	int err = 0;

#ifndef CONFIG_UCLINUX
	if (fsize < 0) {
#ifdef DEBUG
		printk ("setup_frame: Unknown frame format %#x\n",
			regs->format);
#endif
		goto give_sigsegv;
	}
#endif

	frame = get_sigframe(ka, regs, sizeof(*frame));

#ifndef CONFIG_UCLINUX
	if (fsize) {
		err |= copy_to_user (&frame->uc.uc_extra, regs + 1, fsize);
		regs->stkadj = fsize;
	}
#endif

	err |= __put_user((current->exec_domain
			   && current->exec_domain->signal_invmap
			   && sig < 32
			   ? current->exec_domain->signal_invmap[sig]
			   : sig),
			  &frame->sig);
	err |= __put_user(&frame->info, &frame->pinfo);
	err |= __put_user(&frame->uc, &frame->puc);
	err |= copy_siginfo_to_user(&frame->info, info);

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->uc.uc_flags);
	err |= __put_user(0, &frame->uc.uc_link);
	err |= __put_user((void *)current->sas_ss_sp,
			  &frame->uc.uc_stack.ss_sp);
	err |= __put_user(sas_ss_flags(rdusp()),
			  &frame->uc.uc_stack.ss_flags);
	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err |= rt_setup_ucontext(&frame->uc, regs);
	err |= copy_to_user (&frame->uc.uc_sigmask, set, sizeof(*set));

	/* Set up to return from userspace.  */
	err |= __put_user(frame->retcode, &frame->pretcode);

	/* moveq #,d0; notb d0; movea.l #,a5; trap #0 */
	a5 = ((struct switch_stack *)regs - 1)->a5;
	err |= __put_user(0x70004600 + ((__NR_rt_sigreturn ^ 0xff) << 16),
			  (long *)(frame->retcode + 0));
	err != __put_user(0x2a7c0000 + ((a5 >> 16) & 0xffff),
			(long *)(frame->retcode + 4));
	err != __put_user(0x00004e40 + ((a5 & 0xffff) << 16),
			(long *)(frame->retcode + 8));

	if (err)
		goto give_sigsegv;

	push_cache ((unsigned long) &frame->retcode);

	/* Set up registers for signal handler */
	wrusp ((unsigned long) frame);
	regs->pc = (unsigned long) ka->sa.sa_handler;

adjust_stack:
	/* Prepare to skip over the extra stuff in the exception frame.  */
	if (regs->stkadj) {
		struct pt_regs *tregs =
			(struct pt_regs *)((ulong)regs + regs->stkadj);
#if DEBUG
		printk("Performing stackadjust=%04x\n", regs->stkadj);
#endif
		/* This must be copied with decreasing addresses to
                   handle overlaps.  */
		tregs->vector = 0;
		tregs->format = 0;
		tregs->pc = regs->pc;
		tregs->sr = regs->sr;
	}
	return;

give_sigsegv:
	if (sig == SIGSEGV)
		ka->sa.sa_handler = SIG_DFL;
	force_sig(SIGSEGV, current);
	goto adjust_stack;
}

static inline void
handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
{
	switch (regs->d0) {
	case -ERESTARTNOHAND:
		if (!has_handler)
			goto do_restart;
		regs->d0 = -EINTR;
		break;

	case -ERESTARTSYS:
		if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
			regs->d0 = -EINTR;
			break;
		}
	/* fallthrough */
	case -ERESTARTNOINTR:
	do_restart:
		regs->d0 = regs->orig_d0;
		regs->pc -= 2;
		break;
	}
}

/*
 * OK, we're invoking a handler
 */
static void
handle_signal(int sig, struct k_sigaction *ka, siginfo_t *info,
	      sigset_t *oldset, struct pt_regs *regs)
{
	/* are we from a system call? */
	if (regs->orig_d0 >= 0)
		/* If so, check system call restarting.. */
		handle_restart(regs, ka, 1);

	/* set up the stack frame */
	if (ka->sa.sa_flags & SA_SIGINFO)
		setup_rt_frame(sig, ka, info, oldset, regs);
	else
		setup_frame(sig, ka, oldset, regs);

	if (ka->sa.sa_flags & SA_ONESHOT)
		ka->sa.sa_handler = SIG_DFL;

	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
	if (!(ka->sa.sa_flags & SA_NODEFER))
		sigaddset(&current->blocked,sig);
	recalc_sigpending(current);
}

/*
 * 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(sigset_t *oldset, struct pt_regs *regs)
{
	siginfo_t info;
	struct k_sigaction *ka;

	current->thread.esp0 = (unsigned long) regs;

	if (!oldset)
		oldset = &current->blocked;

	for (;;) {
		int signr;

		signr = dequeue_signal(&current->blocked, &info);

		if (!signr)
			break;

		if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) {
			current->exit_code = signr;
			current->state = TASK_STOPPED;
			regs->sr &= ~PS_T;

			/* Did we come from a system call? */
			if (regs->orig_d0 >= 0) {
				/* Restart the system call the same way as
				   if the process were not traced.  */
				struct k_sigaction *ka =
					&current->sig->action[signr-1];
				int has_handler =
					(ka->sa.sa_handler != SIG_IGN &&
					 ka->sa.sa_handler != SIG_DFL);
				handle_restart(regs, ka, has_handler);
			}
			notify_parent(current, SIGCHLD);
			schedule();

			/* We're back.  Did the debugger cancel the sig?  */
			if (!(signr = current->exit_code)) {
			discard_frame:
#ifndef CONFIG_UCLINUX
			    /* Make sure that a faulted bus cycle isn't
			       restarted (only needed on the 680[23]0).  */
			    if (regs->format == 10 || regs->format == 11)
				regs->stkadj = frame_extra_sizes[regs->format];
#endif
			    continue;
			}
			current->exit_code = 0;

			/* The debugger continued.  Ignore SIGSTOP.  */
			if (signr == SIGSTOP)
				goto discard_frame;

			/* Update the siginfo structure.  Is this good?  */
			if (signr != info.si_signo) {
				info.si_signo = signr;
				info.si_errno = 0;
				info.si_code = SI_USER;
				info.si_pid = current->p_pptr->pid;
				info.si_uid = current->p_pptr->uid;
			}

			/* If the (new) signal is now blocked, requeue it.  */
			if (sigismember(&current->blocked, signr)) {
				send_sig_info(signr, &info, current);
				continue;
			}
		}

		ka = &current->sig->action[signr-1];
		if (ka->sa.sa_handler == SIG_IGN) {
			if (signr != SIGCHLD)
				continue;
			/* Check for SIGCHLD: it's special.  */
			while (sys_wait4(-1, NULL, WNOHANG, NULL) > 0)
				/* nothing */;
			continue;
		}

		if (ka->sa.sa_handler == SIG_DFL) {
			int exit_code = signr;

			if (current->pid == 1)
				continue;

			switch (signr) {
			case SIGCONT: case SIGCHLD:
			case SIGWINCH: case SIGURG:
				continue;

			case SIGTSTP: case SIGTTIN: case SIGTTOU:
				if (is_orphaned_pgrp(current->pgrp))
					continue;
				/* FALLTHRU */

			case SIGSTOP: {
				struct signal_struct *sig;
				current->state = TASK_STOPPED;
				current->exit_code = signr;
                                sig = current->p_pptr->sig;
                                if (sig && !(sig->action[SIGCHLD-1].sa.sa_flags 
& SA_NOCLDSTOP))
                                        notify_parent(current, SIGCHLD);
				schedule();
				continue;
			}

			case SIGQUIT: case SIGILL: case SIGTRAP:
			case SIGIOT: case SIGFPE: case SIGSEGV:
			case SIGBUS: case SIGSYS: case SIGXCPU: case SIGXFSZ:
				if (do_coredump(signr, regs))
					exit_code |= 0x80;
				/* FALLTHRU */

			default:
				sig_exit(signr, exit_code, &info);
				/* NOTREACHED */
			}
		}

		/* Whee!  Actually deliver the signal.  */
		handle_signal(signr, ka, &info, oldset, regs);
		return 1;
	}

	/* Did we come from a system call? */
	if (regs->orig_d0 >= 0)
		/* Restart the system call - no handlers present */
		handle_restart(regs, NULL, 0);

	/* If we are about to discard some frame stuff we must copy
	   over the remaining frame. */
	if (regs->stkadj) {
		struct pt_regs *tregs =
		  (struct pt_regs *) ((ulong) regs + regs->stkadj);

		/* This must be copied with decreasing addresses to
		   handle overlaps.  */
		tregs->vector = 0;
		tregs->format = 0;
		tregs->pc = regs->pc;
		tregs->sr = regs->sr;
	}
	return 0;
}


/*
 *	return the correct value for a5/start_data,  mainly for signal
 *	handlers to ensure they get the correct data segment.
 */

unsigned long
get_pic_a5()
{
#ifdef DEBUG
  	unsigned long a5;

	__asm__ __volatile__("movel %/a5,%0"
			     : "=a" (a5));

	if (current->mm->start_data != a5)
#ifdef CONFIG_BINFMT_SHARED_FLAT
	{	int i;

		/* It simply isn't sufficient to check for a5 having changed, we
		 * must verify that the GOT pointers are equal for both segments.
		 */
		for (i=0; i<4; i++) {
			if (*(long *)(current->mm->start_data - 4*i - 4) !=
					*(long *)(a5 - 4*i - 4)) {
				printk("%s: broken a5 (%d) 0x%x (0x%x)\n",
						current->comm,
						i, a5,
						current->mm->start_data);
				break;
			}
		}
	}
#else
		printk("broken a5 0x%x != 0x%x\n", current->mm->start_data, a5);
#endif
#endif
	return current->mm->start_data;
}