signal.c

linux-2.6.15.6

} /* end get_sigframe() */

/*****************************************************************************/
/*
 *
 */
static void setup_frame(int sig, struct k_sigaction *ka, sigset_t *set, struct pt_regs * regs)
{
	struct sigframe __user *frame;
	int rsig;

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

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		goto give_sigsegv;

	rsig = sig;
	if (sig < 32 &&
	    __current_thread_info->exec_domain &&
	    __current_thread_info->exec_domain->signal_invmap)
		rsig = __current_thread_info->exec_domain->signal_invmap[sig];

	if (__put_user(rsig, &frame->sig) < 0)
		goto give_sigsegv;

	if (setup_sigcontext(&frame->sc, set->sig[0]))
		goto give_sigsegv;

	if (_NSIG_WORDS > 1) {
		if (__copy_to_user(frame->extramask, &set->sig[1],
				   sizeof(frame->extramask)))
			goto give_sigsegv;
	}

	/* Set up to return from userspace.  If provided, use a stub
	 * already in userspace.  */
	if (ka->sa.sa_flags & SA_RESTORER) {
		if (__put_user(ka->sa.sa_restorer, &frame->pretcode) < 0)
			goto give_sigsegv;
	}
	else {
		/* Set up the following code on the stack:
		 *	setlos	#__NR_sigreturn,gr7
		 *	tira	gr0,0
		 */
		if (__put_user((void (*)(void))frame->retcode, &frame->pretcode) ||
		    __put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) ||
		    __put_user(0xc0700000, &frame->retcode[1]))
			goto give_sigsegv;

		flush_icache_range((unsigned long) frame->retcode,
				   (unsigned long) (frame->retcode + 2));
	}

	/* set up registers for signal handler */
	regs->sp   = (unsigned long) frame;
	regs->lr   = (unsigned long) &frame->retcode;
	regs->gr8  = sig;

	if (get_personality & FDPIC_FUNCPTRS) {
		struct fdpic_func_descriptor __user *funcptr =
			(struct fdpic_func_descriptor *) ka->sa.sa_handler;
		__get_user(regs->pc, &funcptr->text);
		__get_user(regs->gr15, &funcptr->GOT);
	} else {
		regs->pc   = (unsigned long) ka->sa.sa_handler;
		regs->gr15 = 0;
	}

	set_fs(USER_DS);

#if DEBUG_SIG
	printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
		sig, current->comm, current->pid, frame, regs->pc, frame->pretcode);
#endif

	return;

give_sigsegv:
	if (sig == SIGSEGV)
		ka->sa.sa_handler = SIG_DFL;

	force_sig(SIGSEGV, current);
} /* end setup_frame() */

/*****************************************************************************/
/*
 *
 */
static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
			   sigset_t *set, struct pt_regs * regs)
{
	struct rt_sigframe __user *frame;
	int rsig;

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

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		goto give_sigsegv;

	rsig = sig;
	if (sig < 32 &&
	    __current_thread_info->exec_domain &&
	    __current_thread_info->exec_domain->signal_invmap)
		rsig = __current_thread_info->exec_domain->signal_invmap[sig];

	if (__put_user(rsig,		&frame->sig) ||
	    __put_user(&frame->info,	&frame->pinfo) ||
	    __put_user(&frame->uc,	&frame->puc))
		goto give_sigsegv;

	if (copy_siginfo_to_user(&frame->info, info))
		goto give_sigsegv;

	/* Create the ucontext.  */
	if (__put_user(0, &frame->uc.uc_flags) ||
	    __put_user(0, &frame->uc.uc_link) ||
	    __put_user((void*)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) ||
	    __put_user(sas_ss_flags(regs->sp), &frame->uc.uc_stack.ss_flags) ||
	    __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size))
		goto give_sigsegv;

	if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0]))
		goto give_sigsegv;

	if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)))
		goto give_sigsegv;

	/* Set up to return from userspace.  If provided, use a stub
	 * already in userspace.  */
	if (ka->sa.sa_flags & SA_RESTORER) {
		if (__put_user(ka->sa.sa_restorer, &frame->pretcode))
			goto give_sigsegv;
	}
	else {
		/* Set up the following code on the stack:
		 *	setlos	#__NR_sigreturn,gr7
		 *	tira	gr0,0
		 */
		if (__put_user((void (*)(void))frame->retcode, &frame->pretcode) ||
		    __put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) ||
		    __put_user(0xc0700000, &frame->retcode[1]))
			goto give_sigsegv;

		flush_icache_range((unsigned long) frame->retcode,
				   (unsigned long) (frame->retcode + 2));
	}

	/* Set up registers for signal handler */
	regs->sp  = (unsigned long) frame;
	regs->lr   = (unsigned long) &frame->retcode;
	regs->gr8 = sig;
	regs->gr9 = (unsigned long) &frame->info;

	if (get_personality & FDPIC_FUNCPTRS) {
		struct fdpic_func_descriptor *funcptr =
			(struct fdpic_func_descriptor __user *) ka->sa.sa_handler;
		__get_user(regs->pc, &funcptr->text);
		__get_user(regs->gr15, &funcptr->GOT);
	} else {
		regs->pc   = (unsigned long) ka->sa.sa_handler;
		regs->gr15 = 0;
	}

	set_fs(USER_DS);

#if DEBUG_SIG
	printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n",
		sig, current->comm, current->pid, frame, regs->pc, frame->pretcode);
#endif

	return;

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

} /* end setup_rt_frame() */

/*****************************************************************************/
/*
 * OK, we're invoking a handler
 */
static void handle_signal(unsigned long sig, siginfo_t *info,
			  struct k_sigaction *ka, sigset_t *oldset,
			  struct pt_regs *regs)
{
	/* Are we from a system call? */
	if (in_syscall(regs)) {
		/* If so, check system call restarting.. */
		switch (regs->gr8) {
		case -ERESTART_RESTARTBLOCK:
		case -ERESTARTNOHAND:
			regs->gr8 = -EINTR;
			break;

		case -ERESTARTSYS:
			if (!(ka->sa.sa_flags & SA_RESTART)) {
				regs->gr8 = -EINTR;
				break;
			}
			/* fallthrough */
		case -ERESTARTNOINTR:
			regs->gr8 = regs->orig_gr8;
			regs->pc -= 4;
		}
	}

	/* 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);

	spin_lock_irq(&current->sighand->siglock);
	sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);
	if (!(ka->sa.sa_flags & SA_NODEFER))
		sigaddset(&current->blocked, sig);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
} /* end handle_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.
 */
int do_signal(struct pt_regs *regs, sigset_t *oldset)
{
	struct k_sigaction ka;
	siginfo_t info;
	int signr;

	/*
	 * We want the common case to go fast, which
	 * is why we may in certain cases get here from
	 * kernel mode. Just return without doing anything
	 * if so.
	 */
	if (!user_mode(regs))
		return 1;

	if (try_to_freeze())
		goto no_signal;

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

	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	if (signr > 0) {
		handle_signal(signr, &info, &ka, oldset, regs);
		return 1;
	}

 no_signal:
	/* Did we come from a system call? */
	if (regs->syscallno >= 0) {
		/* Restart the system call - no handlers present */
		if (regs->gr8 == -ERESTARTNOHAND ||
		    regs->gr8 == -ERESTARTSYS ||
		    regs->gr8 == -ERESTARTNOINTR) {
			regs->gr8 = regs->orig_gr8;
			regs->pc -= 4;
		}

		if (regs->gr8 == -ERESTART_RESTARTBLOCK){
			regs->gr8 = __NR_restart_syscall;
			regs->pc -= 4;
		}
	}

	return 0;
} /* end do_signal() */

/*****************************************************************************/
/*
 * notification of userspace execution resumption
 * - triggered by current->work.notify_resume
 */
asmlinkage void do_notify_resume(__u32 thread_info_flags)
{
	/* pending single-step? */
	if (thread_info_flags & _TIF_SINGLESTEP)
		clear_thread_flag(TIF_SINGLESTEP);

	/* deal with pending signal delivery */
	if (thread_info_flags & _TIF_SIGPENDING)
		do_signal(__frame, NULL);

} /* end do_notify_resume() */