signal32.c

h内核

	sigdelsetmask(&blocked, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = blocked;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	if (restore_sigcontext32(&regs, &frame->sf_sc))
		goto badframe;

	/*
	 * Don't let your children do this ...
	 */
	if (current_thread_info()->flags & TIF_SYSCALL_TRACE)
		do_syscall_trace(&regs, 1);
	__asm__ __volatile__(
		"move\t$29, %0\n\t"
		"j\tsyscall_exit"
		:/* no outputs */
		:"r" (&regs));
	/* Unreached */

badframe:
	force_sig(SIGSEGV, current);
}

save_static_function(sys32_rt_sigreturn);
__attribute_used__ noinline static void
_sys32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
{
	struct rt_sigframe32 *frame;
	sigset_t set;
	stack_t st;
	s32 sp;

	frame = (struct rt_sigframe32 *) regs.regs[29];
	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
		goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	if (restore_sigcontext32(&regs, &frame->rs_uc.uc_mcontext))
		goto badframe;

	/* The ucontext contains a stack32_t, so we must convert!  */
	if (__get_user(sp, &frame->rs_uc.uc_stack.ss_sp))
		goto badframe;
	st.ss_size = (long) sp;
	if (__get_user(st.ss_size, &frame->rs_uc.uc_stack.ss_size))
		goto badframe;
	if (__get_user(st.ss_flags, &frame->rs_uc.uc_stack.ss_flags))
		goto badframe;

	/* It is more difficult to avoid calling this function than to
	   call it and ignore errors.  */
	do_sigaltstack(&st, NULL, regs.regs[29]);

	/*
	 * Don't let your children do this ...
	 */
	__asm__ __volatile__(
		"move\t$29, %0\n\t"
		"j\tsyscall_exit"
		:/* no outputs */
		:"r" (&regs));
	/* Unreached */

badframe:
	force_sig(SIGSEGV, current);
}

static inline int setup_sigcontext32(struct pt_regs *regs,
				     struct sigcontext32 *sc)
{
	int err = 0;

	err |= __put_user(regs->cp0_epc, &sc->sc_pc);
	err |= __put_user(regs->cp0_status, &sc->sc_status);

#define save_gp_reg(i) {						\
	err |= __put_user(regs->regs[i], &sc->sc_regs[i]);		\
} while(0)
	__put_user(0, &sc->sc_regs[0]); save_gp_reg(1); save_gp_reg(2);
	save_gp_reg(3); save_gp_reg(4); save_gp_reg(5); save_gp_reg(6);
	save_gp_reg(7); save_gp_reg(8); save_gp_reg(9); save_gp_reg(10);
	save_gp_reg(11); save_gp_reg(12); save_gp_reg(13); save_gp_reg(14);
	save_gp_reg(15); save_gp_reg(16); save_gp_reg(17); save_gp_reg(18);
	save_gp_reg(19); save_gp_reg(20); save_gp_reg(21); save_gp_reg(22);
	save_gp_reg(23); save_gp_reg(24); save_gp_reg(25); save_gp_reg(26);
	save_gp_reg(27); save_gp_reg(28); save_gp_reg(29); save_gp_reg(30);
	save_gp_reg(31);
#undef save_gp_reg

	err |= __put_user(regs->hi, &sc->sc_mdhi);
	err |= __put_user(regs->lo, &sc->sc_mdlo);
	err |= __put_user(regs->cp0_cause, &sc->sc_cause);
	err |= __put_user(regs->cp0_badvaddr, &sc->sc_badvaddr);

	err |= __put_user(!!used_math(), &sc->sc_used_math);

	if (!used_math())
		goto out;

	/* 
	 * Save FPU state to signal context.  Signal handler will "inherit"
	 * current FPU state.
	 */
	preempt_disable();

	if (!is_fpu_owner()) {
		own_fpu();
		restore_fp(current);
	}
	err |= save_fp_context32(sc);

	preempt_enable();

out:
	return err;
}

/*
 * Determine which stack to use..
 */
static inline void *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
				 size_t frame_size)
{
	unsigned long sp;

	/* Default to using normal stack */
	sp = regs->regs[29];

	/*
 	 * FPU emulator may have it's own trampoline active just
 	 * above the user stack, 16-bytes before the next lowest
 	 * 16 byte boundary.  Try to avoid trashing it.
 	 */
 	sp -= 32;

	/* This is the X/Open sanctioned signal stack switching.  */
	if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags (sp) == 0))
		sp = current->sas_ss_sp + current->sas_ss_size;

	return (void *)((sp - frame_size) & ALMASK);
}

static inline void setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
			       int signr, sigset_t *set)
{
	struct sigframe *frame;
	int err = 0;

	frame = get_sigframe(ka, regs, sizeof(*frame));
	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
		goto give_sigsegv;

	/*
	 * Set up the return code ...
	 *
	 *         li      v0, __NR_O32_sigreturn
	 *         syscall
	 */
	err |= __put_user(0x24020000 + __NR_O32_sigreturn, frame->sf_code + 0);
	err |= __put_user(0x0000000c                     , frame->sf_code + 1);
	flush_cache_sigtramp((unsigned long) frame->sf_code);

	err |= setup_sigcontext32(regs, &frame->sf_sc);
	err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
	if (err)
		goto give_sigsegv;

	/*
	 * Arguments to signal handler:
	 *
	 *   a0 = signal number
	 *   a1 = 0 (should be cause)
	 *   a2 = pointer to struct sigcontext
	 *
	 * $25 and c0_epc point to the signal handler, $29 points to the
	 * struct sigframe.
	 */
	regs->regs[ 4] = signr;
	regs->regs[ 5] = 0;
	regs->regs[ 6] = (unsigned long) &frame->sf_sc;
	regs->regs[29] = (unsigned long) frame;
	regs->regs[31] = (unsigned long) frame->sf_code;
	regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;

#if DEBUG_SIG
	printk("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%p\n",
	       current->comm, current->pid,
	       frame, regs->cp0_epc, frame->sf_code);
#endif
        return;

give_sigsegv:
	force_sigsegv(signr, current);
}

static inline void setup_rt_frame(struct k_sigaction * ka,
				  struct pt_regs *regs, int signr,
				  sigset_t *set, siginfo_t *info)
{
	struct rt_sigframe32 *frame;
	int err = 0;
	s32 sp;

	frame = get_sigframe(ka, regs, sizeof(*frame));
	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
		goto give_sigsegv;

	/* Set up to return from userspace.  If provided, use a stub already
	   in userspace.  */
	/*
	 * Set up the return code ...
	 *
	 *         li      v0, __NR_O32_rt_sigreturn
	 *         syscall
	 */
	err |= __put_user(0x24020000 + __NR_O32_rt_sigreturn, frame->rs_code + 0);
	err |= __put_user(0x0000000c                      , frame->rs_code + 1);
	flush_cache_sigtramp((unsigned long) frame->rs_code);

	/* Convert (siginfo_t -> compat_siginfo_t) and copy to user. */
	err |= copy_siginfo_to_user32(&frame->rs_info, info);

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->rs_uc.uc_flags);
	err |= __put_user(0, &frame->rs_uc.uc_link);
	sp = (int) (long) current->sas_ss_sp;
	err |= __put_user(sp,
	                  &frame->rs_uc.uc_stack.ss_sp);
	err |= __put_user(sas_ss_flags(regs->regs[29]),
	                  &frame->rs_uc.uc_stack.ss_flags);
	err |= __put_user(current->sas_ss_size,
	                  &frame->rs_uc.uc_stack.ss_size);
	err |= setup_sigcontext32(regs, &frame->rs_uc.uc_mcontext);
	err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));

	if (err)
		goto give_sigsegv;

	/*
	 * Arguments to signal handler:
	 *
	 *   a0 = signal number
	 *   a1 = 0 (should be cause)
	 *   a2 = pointer to ucontext
	 *
	 * $25 and c0_epc point to the signal handler, $29 points to
	 * the struct rt_sigframe32.
	 */
	regs->regs[ 4] = signr;
	regs->regs[ 5] = (unsigned long) &frame->rs_info;
	regs->regs[ 6] = (unsigned long) &frame->rs_uc;
	regs->regs[29] = (unsigned long) frame;
	regs->regs[31] = (unsigned long) frame->rs_code;
	regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;

#if DEBUG_SIG
	printk("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%p\n",
	       current->comm, current->pid,
	       frame, regs->cp0_epc, frame->rs_code);
#endif
	return;

give_sigsegv:
	force_sigsegv(signr, current);
}

static inline void handle_signal(unsigned long sig, siginfo_t *info,
	struct k_sigaction *ka, sigset_t *oldset, struct pt_regs * regs)
{
	switch (regs->regs[0]) {
	case ERESTART_RESTARTBLOCK:
	case ERESTARTNOHAND:
		regs->regs[2] = EINTR;
		break;
	case ERESTARTSYS:
		if(!(ka->sa.sa_flags & SA_RESTART)) {
			regs->regs[2] = EINTR;
			break;
		}
	/* fallthrough */
	case ERESTARTNOINTR:		/* Userland will reload $v0.  */
		regs->regs[7] = regs->regs[26];
		regs->cp0_epc -= 8;
	}

	regs->regs[0] = 0;		/* Don't deal with this again.  */

	if (ka->sa.sa_flags & SA_SIGINFO)
		setup_rt_frame(ka, regs, sig, oldset, info);
	else
		setup_frame(ka, regs, sig, oldset);

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

int do_signal32(sigset_t *oldset, struct pt_regs *regs)
{
	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(0))
		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:
	/*
	 * Who's code doesn't conform to the restartable syscall convention
	 * dies here!!!  The li instruction, a single machine instruction,
	 * must directly be followed by the syscall instruction.
	 */
	if (regs->regs[0]) {
		if (regs->regs[2] == ERESTARTNOHAND ||
		    regs->regs[2] == ERESTARTSYS ||
		    regs->regs[2] == ERESTARTNOINTR) {
			regs->regs[7] = regs->regs[26];
			regs->cp0_epc -= 8;
		}
		if (regs->regs[2] == ERESTART_RESTARTBLOCK) {
			regs->regs[2] = __NR_O32_restart_syscall;
			regs->regs[7] = regs->regs[26];
			regs->cp0_epc -= 4;
		}
	}
	return 0;
}

asmlinkage int sys32_rt_sigaction(int sig, const struct sigaction32 *act,
				  struct sigaction32 *oact,
				  unsigned int sigsetsize)
{
	struct k_sigaction new_sa, old_sa;
	int ret = -EINVAL;

	/* XXX: Don't preclude handling different sized sigset_t's.  */
	if (sigsetsize != sizeof(sigset_t))
		goto out;

	if (act) {
		int err = 0;

		if (!access_ok(VERIFY_READ, act, sizeof(*act)))
			return -EFAULT;
		err |= __get_user((u32)(u64)new_sa.sa.sa_handler,
		                  &act->sa_handler);
		err |= __get_user(new_sa.sa.sa_flags, &act->sa_flags);
		err |= get_sigset(&new_sa.sa.sa_mask, &act->sa_mask);
		if (err)
			return -EFAULT;
	}

	ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL);

	if (!ret && oact) {
		int err = 0;

		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
			return -EFAULT;

		err |= __put_user((u32)(u64)old_sa.sa.sa_handler,
		                   &oact->sa_handler);
		err |= __put_user(old_sa.sa.sa_flags, &oact->sa_flags);
		err |= put_sigset(&old_sa.sa.sa_mask, &oact->sa_mask);
		if (err)
			return -EFAULT;
	}
out:
	return ret;
}

asmlinkage int sys32_rt_sigprocmask(int how, compat_sigset_t *set,
	compat_sigset_t *oset, unsigned int sigsetsize)
{
	sigset_t old_set, new_set;
	int ret;
	mm_segment_t old_fs = get_fs();

	if (set && get_sigset(&new_set, set))
		return -EFAULT;

	set_fs (KERNEL_DS);
	ret = sys_rt_sigprocmask(how, set ? &new_set : NULL,
				 oset ? &old_set : NULL, sigsetsize);
	set_fs (old_fs);

	if (!ret && oset && put_sigset(&old_set, oset))
		return -EFAULT;

	return ret;
}

asmlinkage int sys32_rt_sigpending(compat_sigset_t *uset,
	unsigned int sigsetsize)
{
	int ret;
	sigset_t set;
	mm_segment_t old_fs = get_fs();

	set_fs (KERNEL_DS);
	ret = sys_rt_sigpending(&set, sigsetsize);
	set_fs (old_fs);

	if (!ret && put_sigset(&set, uset))
		return -EFAULT;

	return ret;
}

asmlinkage int sys32_rt_sigqueueinfo(int pid, int sig, compat_siginfo_t *uinfo)
{
	siginfo_t info;
	int ret;
	mm_segment_t old_fs = get_fs();

	if (copy_from_user (&info, uinfo, 3*sizeof(int)) ||
	    copy_from_user (info._sifields._pad, uinfo->_sifields._pad, SI_PAD_SIZE))
		return -EFAULT;
	set_fs (KERNEL_DS);
	ret = sys_rt_sigqueueinfo(pid, sig, &info);
	set_fs (old_fs);
	return ret;
}