asmlinkage void do_sigreturn(struct pt_regs *regs)
{
	struct signal_frame __user *sf;
	unsigned long up_psr, pc, npc;
	sigset_t set;
	__siginfo_fpu_t __user *fpu_save;
	int err;

	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	synchronize_user_stack();

	sf = (struct signal_frame __user *) regs->u_regs[UREG_FP];

	/* 1. Make sure we are not getting garbage from the user */
	if (!access_ok(VERIFY_READ, sf, sizeof(*sf)))
		goto segv_and_exit;

	if (((unsigned long) sf) & 3)
		goto segv_and_exit;

	err = __get_user(pc,  &sf->info.si_regs.pc);
	err |= __get_user(npc, &sf->info.si_regs.npc);

	if ((pc | npc) & 3)
		goto segv_and_exit;

	/* 2. Restore the state */
	up_psr = regs->psr;
	err |= __copy_from_user(regs, &sf->info.si_regs, sizeof(struct pt_regs));

	/* User can only change condition codes and FPU enabling in %psr. */
	regs->psr = (up_psr & ~(PSR_ICC | PSR_EF))
		  | (regs->psr & (PSR_ICC | PSR_EF));

	/* Prevent syscall restart.  */
	pt_regs_clear_syscall(regs);

	err |= __get_user(fpu_save, &sf->fpu_save);

	if (fpu_save)
		err |= restore_fpu_state(regs, fpu_save);

	/* This is pretty much atomic, no amount locking would prevent
	 * the races which exist anyways.
	 */
	err |= __get_user(set.sig[0], &sf->info.si_mask);
	err |= __copy_from_user(&set.sig[1], &sf->extramask,
			        (_NSIG_WORDS-1) * sizeof(unsigned int));
			   
	if (err)
		goto segv_and_exit;

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

segv_and_exit:
	force_sig(SIGSEGV, current);
}

/*
 * OK, we're invoking a handler
 */	
static void
handle_signal(unsigned long sig, struct k_sigaction *ka,
	      siginfo_t *info, sigset_t *oldset,
	      struct pt_regs * regs, int syscall)
{
	struct thread_info *thread = current_thread_info();
	struct task_struct *tsk = current;
	int usig = sig;
	int ret;

	/*
	 * If we were from a system call, check for system call restarting...
	 */
	if (syscall) {
		switch (regs->ARM_r0) {
		case -ERESTART_RESTARTBLOCK:
		case -ERESTARTNOHAND:
			regs->ARM_r0 = -EINTR;
			break;
		case -ERESTARTSYS:
			if (!(ka->sa.sa_flags & SA_RESTART)) {
				regs->ARM_r0 = -EINTR;
				break;
			}
			/* fallthrough */
		case -ERESTARTNOINTR:
			restart_syscall(regs);
		}
	}

	/*
	 * translate the signal
	 */
	if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
		usig = thread->exec_domain->signal_invmap[usig];

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

	/*
	 * Check that the resulting registers are actually sane.
	 */
	ret |= !valid_user_regs(regs);

	if (ret != 0) {
		force_sigsegv(sig, tsk);
		return;
	}

	/*
	 * Block the signal if we were successful.
	 */
	spin_lock_irq(&tsk->sighand->siglock);
	sigorsets(&tsk->blocked, &tsk->blocked,
		  &ka->sa.sa_mask);
	if (!(ka->sa.sa_flags & SA_NODEFER))
		sigaddset(&tsk->blocked, sig);
	recalc_sigpending();
	spin_unlock_irq(&tsk->sighand->siglock);

}

void do_rt_sigreturn(struct pt_regs *regs)
{
	struct rt_signal_frame __user *sf;
	unsigned long tpc, tnpc, tstate;
	__siginfo_fpu_t __user *fpu_save;
	__siginfo_rwin_t __user *rwin_save;
	sigset_t set;
	int err;

	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	synchronize_user_stack ();
	sf = (struct rt_signal_frame __user *)
		(regs->u_regs [UREG_FP] + STACK_BIAS);

	/* 1. Make sure we are not getting garbage from the user */
	if (((unsigned long) sf) & 3)
		goto segv;

	err = get_user(tpc, &sf->regs.tpc);
	err |= __get_user(tnpc, &sf->regs.tnpc);
	if (test_thread_flag(TIF_32BIT)) {
		tpc &= 0xffffffff;
		tnpc &= 0xffffffff;
	}
	err |= ((tpc | tnpc) & 3);

	/* 2. Restore the state */
	err |= __get_user(regs->y, &sf->regs.y);
	err |= __get_user(tstate, &sf->regs.tstate);
	err |= copy_from_user(regs->u_regs, sf->regs.u_regs, sizeof(regs->u_regs));

	/* User can only change condition codes and %asi in %tstate. */
	regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
	regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));

	err |= __get_user(fpu_save, &sf->fpu_save);
	if (!err && fpu_save)
		err |= restore_fpu_state(regs, fpu_save);

	err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t));
	err |= restore_altstack(&sf->stack);
	if (err)
		goto segv;

	err |= __get_user(rwin_save, &sf->rwin_save);
	if (!err && rwin_save) {
		if (restore_rwin_state(rwin_save))
			goto segv;
	}

	regs->tpc = tpc;
	regs->tnpc = tnpc;

	/* Prevent syscall restart.  */
	pt_regs_clear_syscall(regs);

	set_current_blocked(&set);
	return;
segv:
	force_sig(SIGSEGV, current);
}

/*
 * This routine handles page faults.  It determines the address, and the
 * problem, and then passes it handle_page_fault() for normal DTLB and
 * ITLB issues, and for DMA or SN processor faults when we are in user
 * space.  For the latter, if we're in kernel mode, we just save the
 * interrupt away appropriately and return immediately.  We can't do
 * page faults for user code while in kernel mode.
 */
void do_page_fault(struct pt_regs *regs, int fault_num,
		   unsigned long address, unsigned long write)
{
	int is_page_fault;

#ifdef CONFIG_KPROBES
	/*
	 * This is to notify the fault handler of the kprobes.  The
	 * exception code is redundant as it is also carried in REGS,
	 * but we pass it anyhow.
	 */
	if (notify_die(DIE_PAGE_FAULT, "page fault", regs, -1,
		       regs->faultnum, SIGSEGV) == NOTIFY_STOP)
		return;
#endif

#ifdef __tilegx__
	/*
	 * We don't need early do_page_fault_ics() support, since unlike
	 * Pro we don't need to worry about unlocking the atomic locks.
	 * There is only one current case in GX where we touch any memory
	 * under ICS other than our own kernel stack, and we handle that
	 * here.  (If we crash due to trying to touch our own stack,
	 * we're in too much trouble for C code to help out anyway.)
	 */
	if (write & ~1) {
		unsigned long pc = write & ~1;
		if (pc >= (unsigned long) __start_unalign_asm_code &&
		    pc < (unsigned long) __end_unalign_asm_code) {
			struct thread_info *ti = current_thread_info();
			/*
			 * Our EX_CONTEXT is still what it was from the
			 * initial unalign exception, but now we've faulted
			 * on the JIT page.  We would like to complete the
			 * page fault however is appropriate, and then retry
			 * the instruction that caused the unalign exception.
			 * Our state has been "corrupted" by setting the low
			 * bit in "sp", and stashing r0..r3 in the
			 * thread_info area, so we revert all of that, then
			 * continue as if this were a normal page fault.
			 */
			regs->sp &= ~1UL;
			regs->regs[0] = ti->unalign_jit_tmp[0];
			regs->regs[1] = ti->unalign_jit_tmp[1];
			regs->regs[2] = ti->unalign_jit_tmp[2];
			regs->regs[3] = ti->unalign_jit_tmp[3];
			write &= 1;
		} else {
			pr_alert("%s/%d: ICS set at page fault at %#lx: %#lx\n",
				 current->comm, current->pid, pc, address);
			show_regs(regs);
			do_group_exit(SIGKILL);
			return;
		}
	}
#else
	/* This case should have been handled by do_page_fault_ics(). */
	BUG_ON(write & ~1);
#endif

#if CHIP_HAS_TILE_DMA()
	/*
	 * If it's a DMA fault, suspend the transfer while we're
	 * handling the miss; we'll restart after it's handled.  If we
	 * don't suspend, it's possible that this process could swap
	 * out and back in, and restart the engine since the DMA is
	 * still 'running'.
	 */
	if (fault_num == INT_DMATLB_MISS ||
	    fault_num == INT_DMATLB_ACCESS ||
	    fault_num == INT_DMATLB_MISS_DWNCL ||
	    fault_num == INT_DMATLB_ACCESS_DWNCL) {
		__insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__SUSPEND_MASK);
		while (__insn_mfspr(SPR_DMA_USER_STATUS) &
		       SPR_DMA_STATUS__BUSY_MASK)
			;
	}
#endif

	/* Validate fault num and decide if this is a first-time page fault. */
	switch (fault_num) {
	case INT_ITLB_MISS:
	case INT_DTLB_MISS:
#if CHIP_HAS_TILE_DMA()
	case INT_DMATLB_MISS:
	case INT_DMATLB_MISS_DWNCL:
#endif
		is_page_fault = 1;
		break;

	case INT_DTLB_ACCESS:
#if CHIP_HAS_TILE_DMA()
//.........这里部分代码省略.........

static int 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 err = 0;
	int signal;

	frame = get_sigframe(ka, regs->regs[REG_SP], sizeof(*frame));

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

	signal = current_thread_info()->exec_domain
		&& current_thread_info()->exec_domain->signal_invmap
		&& sig < 32
		? current_thread_info()->exec_domain->signal_invmap[sig]
		: sig;

	err |= __put_user(&frame->info, &frame->pinfo);
	err |= __put_user(&frame->uc, &frame->puc);
	err |= copy_siginfo_to_user(&frame->info, info);

	/* Give up earlier as i386, in case */
	if (err)
		goto give_sigsegv;

	/* 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(regs->regs[REG_SP]),
			  &frame->uc.uc_stack.ss_flags);
	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err |= setup_sigcontext(&frame->uc.uc_mcontext,
			        regs, set->sig[0]);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	/* Give up earlier as i386, in case */
	if (err)
		goto give_sigsegv;

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	if (ka->sa.sa_flags & SA_RESTORER) {
		/*
		 * On SH5 all edited pointers are subject to NEFF
		 */
		DEREF_REG_PR = neff_sign_extend((unsigned long)
			ka->sa.sa_restorer | 0x1);
	} else {
		/*
		 * Different approach on SH5.
	         * . Endianness independent asm code gets placed in entry.S .
		 *   This is limited to four ASM instructions corresponding
		 *   to two long longs in size.
		 * . err checking is done on the else branch only
		 * . flush_icache_range() is called upon __put_user() only
		 * . all edited pointers are subject to NEFF
		 * . being code, linker turns ShMedia bit on, always
		 *   dereference index -1.
		 */
		DEREF_REG_PR = neff_sign_extend((unsigned long)
			frame->retcode | 0x01);

		if (__copy_to_user(frame->retcode,
			(void *)((unsigned long)sa_default_rt_restorer & (~1)), 16) != 0)
			goto give_sigsegv;

		/* Cohere the trampoline with the I-cache. */
		flush_icache_range(DEREF_REG_PR-1, DEREF_REG_PR-1+15);
	}

	/*
	 * Set up registers for signal handler.
	 * All edited pointers are subject to NEFF.
	 */
	regs->regs[REG_SP] = neff_sign_extend((unsigned long)frame);
	regs->regs[REG_ARG1] = signal; /* Arg for signal handler */
	regs->regs[REG_ARG2] = (unsigned long long)(unsigned long)(signed long)&frame->info;
	regs->regs[REG_ARG3] = (unsigned long long)(unsigned long)(signed long)&frame->uc.uc_mcontext;
	regs->pc = neff_sign_extend((unsigned long)ka->sa.sa_handler);

	set_fs(USER_DS);

	pr_debug("SIG deliver (#%d,%s:%d): sp=%p pc=%08Lx%08Lx link=%08Lx%08Lx\n",
		 signal, current->comm, current->pid, frame,
		 regs->pc >> 32, regs->pc & 0xffffffff,
		 DEREF_REG_PR >> 32, DEREF_REG_PR & 0xffffffff);

	return 0;

give_sigsegv:
	force_sigsegv(sig, current);
	return -EFAULT;
}

static int get_current_node(void)
{
	return cpu_data(current_thread_info()->cpu).phys_proc_id;
}

//.........这里部分代码省略.........
		 * If there's an owner, wait for it to either
		 * release the lock or go to sleep.
		 */
		owner = ACCESS_ONCE(lock->owner);
		if (owner && !mutex_spin_on_owner(lock, owner))
			break;

		if (atomic_cmpxchg(&lock->count, 1, 0) == 1) {
			lock_acquired(&lock->dep_map, ip);
			mutex_set_owner(lock);
			preempt_enable();
			return 0;
		}

		/*
		 * When there's no owner, we might have preempted between the
		 * owner acquiring the lock and setting the owner field. If
		 * we're an RT task that will live-lock because we won't let
		 * the owner complete.
		 */
		if (!owner && (need_resched() || rt_task(task)))
			break;

		/*
		 * The cpu_relax() call is a compiler barrier which forces
		 * everything in this loop to be re-loaded. We don't need
		 * memory barriers as we'll eventually observe the right
		 * values at the cost of a few extra spins.
		 */
		arch_mutex_cpu_relax();
	}
#endif
	spin_lock_mutex(&lock->wait_lock, flags);

	debug_mutex_lock_common(lock, &waiter);
	debug_mutex_add_waiter(lock, &waiter, task_thread_info(task));

	/* add waiting tasks to the end of the waitqueue (FIFO): */
	list_add_tail(&waiter.list, &lock->wait_list);
	waiter.task = task;

	if (atomic_xchg(&lock->count, -1) == 1)
		goto done;

	lock_contended(&lock->dep_map, ip);

	for (;;) {
		/*
		 * Lets try to take the lock again - this is needed even if
		 * we get here for the first time (shortly after failing to
		 * acquire the lock), to make sure that we get a wakeup once
		 * it's unlocked. Later on, if we sleep, this is the
		 * operation that gives us the lock. We xchg it to -1, so
		 * that when we release the lock, we properly wake up the
		 * other waiters:
		 */
		if (atomic_xchg(&lock->count, -1) == 1)
			break;

		/*
		 * got a signal? (This code gets eliminated in the
		 * TASK_UNINTERRUPTIBLE case.)
		 */
		if (unlikely(signal_pending_state(state, task))) {
			mutex_remove_waiter(lock, &waiter,
					    task_thread_info(task));
			mutex_release(&lock->dep_map, 1, ip);
			spin_unlock_mutex(&lock->wait_lock, flags);

			debug_mutex_free_waiter(&waiter);
			preempt_enable();
			return -EINTR;
		}
		__set_task_state(task, state);

		/* didn't get the lock, go to sleep: */
		spin_unlock_mutex(&lock->wait_lock, flags);
		preempt_enable_no_resched();
		schedule();
		preempt_disable();
		spin_lock_mutex(&lock->wait_lock, flags);
	}

done:
	lock_acquired(&lock->dep_map, ip);
	/* got the lock - rejoice! */
	mutex_remove_waiter(lock, &waiter, current_thread_info());
	mutex_set_owner(lock);

	/* set it to 0 if there are no waiters left: */
	if (likely(list_empty(&lock->wait_list)))
		atomic_set(&lock->count, 0);

	spin_unlock_mutex(&lock->wait_lock, flags);

	debug_mutex_free_waiter(&waiter);
	preempt_enable();

	return 0;
}

int __range_ok(unsigned long addr, unsigned long size)
{
	unsigned long limit = current_thread_info()->addr_limit.seg;
	return !((addr < limit && size <= limit - addr) ||
		 is_arch_mappable_range(addr, size));
}

static int 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 err = 0;
	int signal;

	frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));

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

	signal = current_thread_info()->exec_domain
		&& current_thread_info()->exec_domain->signal_invmap
		&& sig < 32
		? current_thread_info()->exec_domain->signal_invmap[sig]
		: sig;

	err |= copy_siginfo_to_user(&frame->info, info);

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->uc.uc_flags);
	err |= __put_user(NULL, &frame->uc.uc_link);
	err |= __put_user((void *)current->sas_ss_sp,
			  &frame->uc.uc_stack.ss_sp);
	err |= __put_user(sas_ss_flags(regs->regs[15]),
			  &frame->uc.uc_stack.ss_flags);
	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err |= setup_sigcontext(&frame->uc.uc_mcontext,
			        regs, set->sig[0]);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	if (ka->sa.sa_flags & SA_RESTORER) {
		regs->pr = (unsigned long) ka->sa.sa_restorer;
#ifdef CONFIG_VSYSCALL
	} else if (likely(current->mm->context.vdso)) {
		regs->pr = VDSO_SYM(&__kernel_rt_sigreturn);
#endif
	} else {
		/* Generate return code (system call to rt_sigreturn) */
		err |= __put_user(MOVW(7), &frame->retcode[0]);
		err |= __put_user(TRAP_NOARG, &frame->retcode[1]);
		err |= __put_user(OR_R0_R0, &frame->retcode[2]);
		err |= __put_user(OR_R0_R0, &frame->retcode[3]);
		err |= __put_user(OR_R0_R0, &frame->retcode[4]);
		err |= __put_user(OR_R0_R0, &frame->retcode[5]);
		err |= __put_user(OR_R0_R0, &frame->retcode[6]);
		err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]);
		regs->pr = (unsigned long) frame->retcode;
		flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));
	}

	if (err)
		goto give_sigsegv;

	/* Set up registers for signal handler */
	regs->regs[15] = (unsigned long) frame;
	regs->regs[4] = signal; /* Arg for signal handler */
	regs->regs[5] = (unsigned long) &frame->info;
	regs->regs[6] = (unsigned long) &frame->uc;

	if (current->personality & FDPIC_FUNCPTRS) {
		struct fdpic_func_descriptor __user *funcptr =
			(struct fdpic_func_descriptor __user *)ka->sa.sa_handler;

		err |= __get_user(regs->pc, &funcptr->text);
		err |= __get_user(regs->regs[12], &funcptr->GOT);
	} else
		regs->pc = (unsigned long)ka->sa.sa_handler;

	if (err)
		goto give_sigsegv;

	set_fs(USER_DS);

	pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n",
		 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);

	return 0;

give_sigsegv:
	force_sigsegv(sig, current);
	return -EFAULT;
}

	/* avoid HT sibilings if possible */
	if (cpumask_empty(tmp))
		cpumask_andnot(tmp, cpu_online_mask, pad_busy_cpus);
	if (cpumask_empty(tmp)) {
		mutex_unlock(&isolated_cpus_lock);
		return;
	}
	for_each_cpu(cpu, tmp) {
		if (cpu_weight[cpu] < min_weight) {
			min_weight = cpu_weight[cpu];
			preferred_cpu = cpu;
		}
	}

	if (tsk_in_cpu[tsk_index] != -1)
		cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
	tsk_in_cpu[tsk_index] = preferred_cpu;
	cpumask_set_cpu(preferred_cpu, pad_busy_cpus);
	cpu_weight[preferred_cpu]++;
	mutex_unlock(&isolated_cpus_lock);

	set_cpus_allowed_ptr(current, cpumask_of(preferred_cpu));
}

static void exit_round_robin(unsigned int tsk_index)
{
	struct cpumask *pad_busy_cpus = to_cpumask(pad_busy_cpus_bits);
	cpumask_clear_cpu(tsk_in_cpu[tsk_index], pad_busy_cpus);
	tsk_in_cpu[tsk_index] = -1;
}

static unsigned int idle_pct = 5; /* percentage */
static unsigned int round_robin_time = 10; /* second */
static int power_saving_thread(void *data)
{
	struct sched_param param = {.sched_priority = 1};
	int do_sleep;
	unsigned int tsk_index = (unsigned long)data;
	u64 last_jiffies = 0;

	sched_setscheduler(current, SCHED_RR, &param);

	while (!kthread_should_stop()) {
		int cpu;
		u64 expire_time;

		try_to_freeze();

		/* round robin to cpus */
		if (last_jiffies + round_robin_time * HZ < jiffies) {
			last_jiffies = jiffies;
			round_robin_cpu(tsk_index);
		}

		do_sleep = 0;

		current_thread_info()->status &= ~TS_POLLING;
		/*
		 * TS_POLLING-cleared state must be visible before we test
		 * NEED_RESCHED:
		 */
		smp_mb();

		expire_time = jiffies + HZ * (100 - idle_pct) / 100;

		while (!need_resched()) {
			local_irq_disable();
			cpu = smp_processor_id();
			clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
				&cpu);
			stop_critical_timings();

			__monitor((void *)&current_thread_info()->flags, 0, 0);
			smp_mb();
			if (!need_resched())
				__mwait(power_saving_mwait_eax, 1);

			start_critical_timings();
			clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
				&cpu);
			local_irq_enable();

			if (jiffies > expire_time) {
				do_sleep = 1;
				break;
			}
		}

		current_thread_info()->status |= TS_POLLING;

		/*
		 * current sched_rt has threshold for rt task running time.
		 * When a rt task uses 95% CPU time, the rt thread will be
		 * scheduled out for 5% CPU time to not starve other tasks. But
		 * the mechanism only works when all CPUs have RT task running,
		 * as if one CPU hasn't RT task, RT task from other CPUs will
		 * borrow CPU time from this CPU and cause RT task use > 95%
		 * CPU time. To make 'avoid starvation' work, takes a nap here.
		 */
		if (do_sleep)
//.........这里部分代码省略.........

static void setup_rt_frame(struct k_sigaction *ka, struct pt_regs *regs,
			   int signo, sigset_t *oldset, siginfo_t *info)
{
	struct rt_signal_frame __user *sf;
	int sigframe_size;
	unsigned int psr;
	int err;

	synchronize_user_stack();
	sigframe_size = RT_ALIGNEDSZ;
	if (!used_math())
		sigframe_size -= sizeof(__siginfo_fpu_t);
	sf = (struct rt_signal_frame __user *)
		get_sigframe(&ka->sa, regs, sigframe_size);
	if (invalid_frame_pointer(sf, sigframe_size))
		goto sigill;
	if (current_thread_info()->w_saved != 0)
		goto sigill;

	err  = __put_user(regs->pc, &sf->regs.pc);
	err |= __put_user(regs->npc, &sf->regs.npc);
	err |= __put_user(regs->y, &sf->regs.y);
	psr = regs->psr;
	if (used_math())
		psr |= PSR_EF;
	err |= __put_user(psr, &sf->regs.psr);
	err |= __copy_to_user(&sf->regs.u_regs, regs->u_regs, sizeof(regs->u_regs));
	err |= __put_user(0, &sf->extra_size);

	if (psr & PSR_EF) {
		err |= save_fpu_state(regs, &sf->fpu_state);
		err |= __put_user(&sf->fpu_state, &sf->fpu_save);
	} else {
		err |= __put_user(0, &sf->fpu_save);
	}
	err |= __copy_to_user(&sf->mask, &oldset->sig[0], sizeof(sigset_t));
	
	/* Setup sigaltstack */
	err |= __put_user(current->sas_ss_sp, &sf->stack.ss_sp);
	err |= __put_user(sas_ss_flags(regs->u_regs[UREG_FP]), &sf->stack.ss_flags);
	err |= __put_user(current->sas_ss_size, &sf->stack.ss_size);
	
	err |= __copy_to_user(sf, (char *) regs->u_regs[UREG_FP],
			      sizeof(struct reg_window32));

	err |= copy_siginfo_to_user(&sf->info, info);

	if (err)
		goto sigsegv;

	regs->u_regs[UREG_FP] = (unsigned long) sf;
	regs->u_regs[UREG_I0] = signo;
	regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
	regs->u_regs[UREG_I2] = (unsigned long) &sf->regs;

	regs->pc = (unsigned long) ka->sa.sa_handler;
	regs->npc = (regs->pc + 4);

	if (ka->ka_restorer)
		regs->u_regs[UREG_I7] = (unsigned long)ka->ka_restorer;
	else {
		regs->u_regs[UREG_I7] = (unsigned long)(&(sf->insns[0]) - 2);

		/* mov __NR_sigreturn, %g1 */
		err |= __put_user(0x821020d8, &sf->insns[0]);

		/* t 0x10 */
		err |= __put_user(0x91d02010, &sf->insns[1]);
		if (err)
			goto sigsegv;

		/* Flush instruction space. */
		flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0]));
	}
	return;

sigill:
	do_exit(SIGILL);
sigsegv:
	force_sigsegv(signo, current);
}

static void setup_frame(struct k_sigaction *ka, struct pt_regs *regs,
			int signo, sigset_t *oldset)
{
	struct signal_frame __user *sf;
	int sigframe_size, err;

	/* 1. Make sure everything is clean */
	synchronize_user_stack();

	sigframe_size = SF_ALIGNEDSZ;
	if (!used_math())
		sigframe_size -= sizeof(__siginfo_fpu_t);

	sf = (struct signal_frame __user *)
		get_sigframe(&ka->sa, regs, sigframe_size);

	if (invalid_frame_pointer(sf, sigframe_size))
		goto sigill_and_return;

	if (current_thread_info()->w_saved != 0)
		goto sigill_and_return;

	/* 2. Save the current process state */
	err = __copy_to_user(&sf->info.si_regs, regs, sizeof(struct pt_regs));
	
	err |= __put_user(0, &sf->extra_size);

	if (used_math()) {
		err |= save_fpu_state(regs, &sf->fpu_state);
		err |= __put_user(&sf->fpu_state, &sf->fpu_save);
	} else {
		err |= __put_user(0, &sf->fpu_save);
	}

	err |= __put_user(oldset->sig[0], &sf->info.si_mask);
	err |= __copy_to_user(sf->extramask, &oldset->sig[1],
			      (_NSIG_WORDS - 1) * sizeof(unsigned int));
	err |= __copy_to_user(sf, (char *) regs->u_regs[UREG_FP],
			      sizeof(struct reg_window32));
	if (err)
		goto sigsegv;
	
	/* 3. signal handler back-trampoline and parameters */
	regs->u_regs[UREG_FP] = (unsigned long) sf;
	regs->u_regs[UREG_I0] = signo;
	regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
	regs->u_regs[UREG_I2] = (unsigned long) &sf->info;

	/* 4. signal handler */
	regs->pc = (unsigned long) ka->sa.sa_handler;
	regs->npc = (regs->pc + 4);

	/* 5. return to kernel instructions */
	if (ka->ka_restorer)
		regs->u_regs[UREG_I7] = (unsigned long)ka->ka_restorer;
	else {
		regs->u_regs[UREG_I7] = (unsigned long)(&(sf->insns[0]) - 2);

		/* mov __NR_sigreturn, %g1 */
		err |= __put_user(0x821020d8, &sf->insns[0]);

		/* t 0x10 */
		err |= __put_user(0x91d02010, &sf->insns[1]);
		if (err)
			goto sigsegv;

		/* Flush instruction space. */
		flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0]));
	}
	return;

sigill_and_return:
	do_exit(SIGILL);
sigsegv:
	force_sigsegv(signo, current);
}

static long
restore_sigcontext (struct sigcontext __user *sc, struct sigscratch *scr)
{
	unsigned long ip, flags, nat, um, cfm, rsc;
	long err;

	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	/* restore scratch that always needs gets updated during signal delivery: */
	err  = __get_user(flags, &sc->sc_flags);
	err |= __get_user(nat, &sc->sc_nat);
	err |= __get_user(ip, &sc->sc_ip);			/* instruction pointer */
	err |= __get_user(cfm, &sc->sc_cfm);
	err |= __get_user(um, &sc->sc_um);			/* user mask */
	err |= __get_user(rsc, &sc->sc_ar_rsc);
	err |= __get_user(scr->pt.ar_unat, &sc->sc_ar_unat);
	err |= __get_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);
	err |= __get_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
	err |= __get_user(scr->pt.pr, &sc->sc_pr);		/* predicates */
	err |= __get_user(scr->pt.b0, &sc->sc_br[0]);		/* b0 (rp) */
	err |= __get_user(scr->pt.b6, &sc->sc_br[6]);		/* b6 */
	err |= __copy_from_user(&scr->pt.r1, &sc->sc_gr[1], 8);	/* r1 */
	err |= __copy_from_user(&scr->pt.r8, &sc->sc_gr[8], 4*8);	/* r8-r11 */
	err |= __copy_from_user(&scr->pt.r12, &sc->sc_gr[12], 2*8);	/* r12-r13 */
	err |= __copy_from_user(&scr->pt.r15, &sc->sc_gr[15], 8);	/* r15 */

	scr->pt.cr_ifs = cfm | (1UL << 63);
	scr->pt.ar_rsc = rsc | (3 << 2); /* force PL3 */

	/* establish new instruction pointer: */
	scr->pt.cr_iip = ip & ~0x3UL;
	ia64_psr(&scr->pt)->ri = ip & 0x3;
	scr->pt.cr_ipsr = (scr->pt.cr_ipsr & ~IA64_PSR_UM) | (um & IA64_PSR_UM);

	scr->scratch_unat = ia64_put_scratch_nat_bits(&scr->pt, nat);

	if (!(flags & IA64_SC_FLAG_IN_SYSCALL)) {
		/* Restore most scratch-state only when not in syscall. */
		err |= __get_user(scr->pt.ar_ccv, &sc->sc_ar_ccv);		/* ar.ccv */
		err |= __get_user(scr->pt.b7, &sc->sc_br[7]);			/* b7 */
		err |= __get_user(scr->pt.r14, &sc->sc_gr[14]);			/* r14 */
		err |= __copy_from_user(&scr->pt.ar_csd, &sc->sc_ar25, 2*8); /* ar.csd & ar.ssd */
		err |= __copy_from_user(&scr->pt.r2, &sc->sc_gr[2], 2*8);	/* r2-r3 */
		err |= __copy_from_user(&scr->pt.r16, &sc->sc_gr[16], 16*8);	/* r16-r31 */
	}

	if ((flags & IA64_SC_FLAG_FPH_VALID) != 0) {
		struct ia64_psr *psr = ia64_psr(&scr->pt);

		err |= __copy_from_user(current->thread.fph, &sc->sc_fr[32], 96*16);
		psr->mfh = 0;	/* drop signal handler's fph contents... */
		preempt_disable();
		if (psr->dfh)
			ia64_drop_fpu(current);
		else {
			/* We already own the local fph, otherwise psr->dfh wouldn't be 0.  */
			__ia64_load_fpu(current->thread.fph);
			ia64_set_local_fpu_owner(current);
		}
		preempt_enable();
	}
	return err;
}

static void
setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
	       sigset_t *set, struct exregs_regs *regs)
{
	struct rt_sigframe *frame = get_sigframe(ka, regs, sizeof(*frame));
	unsigned long handler = (unsigned long)ka->sa.sa_handler;
	int err = 0;
	printk_dbg("%s called\n", __func__);

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

	__put_user_error(&frame->info, &frame->pinfo, err);
	__put_user_error(&frame->uc, &frame->puc, err);
	err |= copy_siginfo_to_user(&frame->info, info);

	/* Clear all the bits of the ucontext we don't use.  */
	err |= clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));

	err |= setup_sigcontext(&frame->uc.uc_mcontext, /*&frame->fpstate,*/
				regs, set->sig[0]);
	err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	err |= __put_user(handler, &frame->sig_ip);
	printk_dbg("%s frame->sig_ip = %lx\n", __func__, handler);

	if (!err)
		err = setup_return(regs, ka, &frame->retcode, frame,
				&frame->lr, &frame->usig, usig);

	if (!err) {
		/*
		 * For realtime signals we must also set the second and third
		 * arguments for the signal handler.
		 *   -- Peter Maydell <[email protected]> 2000-12-06
		 */
//		ARM_put_r1(regs, (unsigned long)frame->pinfo);
//		ARM_put_r2(regs, (unsigned long)frame->puc);
	}

	if (err)
		goto badframe;

	regs->ip = TASK_SIG_BASE;
	switch (regs->syscall_action)
	{
	case 1:	/* Syscall */
		regs->ip += ((unsigned long)&__wombat_user_rt_sigentry) & ~PAGE_MASK;
		break;
	case 0:	/* Fault */
	case 2:	/* Restart syscall */
		regs->ip += ((unsigned long)&__wombat_user_rt_sigentry_restart) & ~PAGE_MASK;
		break;
	case 4:	/* Interrupt syscall */
		regs->ip += ((unsigned long)&__wombat_user_rt_sigentry_int) & ~PAGE_MASK;
		break;
	default:
		BUG();
	}

	set_need_restart(current_thread_info(), regs->ip,
			regs->sp, regs->flags);

	printk_dbg("SIG rt deliver (%s:%d:%lx): sp=%p pc=%p\n",
			current->comm, current->pid,
			current_thread_info()->user_tid.raw,
			frame, (void*)regs->ip);

	return;

badframe:
	force_sigsegv(usig, current);
	return;
}

/* Setup a VMA at program startup for the vsyscall page */
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp,
				unsigned long map_address)
{
	struct mm_struct *mm = current->mm;
	unsigned long addr = map_address;
	int ret = 0;
	bool compat;
	unsigned long flags;

	if (vdso_enabled == VDSO_DISABLED && map_address == 0) {
		current->mm->context.vdso = NULL;
		return 0;
	}

	flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC | VM_MAYWRITE |
		mm->def_flags;

	ret = -ENOMEM;
	if (ub_memory_charge(mm, PAGE_SIZE, flags, NULL, UB_SOFT))
		goto err_charge;

	down_write(&mm->mmap_sem);

	/* Test compat mode once here, in case someone
	   changes it via sysctl */
	compat = (vdso_enabled == VDSO_COMPAT);

	map_compat_vdso(compat);

	if (!compat || map_address) {
		addr = get_unmapped_area_prot(NULL, addr, PAGE_SIZE, 0, 0, 1);
		if (IS_ERR_VALUE(addr)) {
			ret = addr;
			goto up_fail;
		}
	} else
		addr = VDSO_HIGH_BASE;

	current->mm->context.vdso = (void *)addr;

	if (compat_uses_vma || !compat || map_address) {
		/*
		 * MAYWRITE to allow gdb to COW and set breakpoints
		 *
		 * Make sure the vDSO gets into every core dump.
		 * Dumping its contents makes post-mortem fully
		 * interpretable later without matching up the same
		 * kernel and hardware config to see what PC values
		 * meant.
		 */
		ret = install_special_mapping(mm, addr, PAGE_SIZE,
					      VM_READ|VM_EXEC|
					      VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
					      VM_ALWAYSDUMP,
					      vdso32_pages);

		if (ret)
			goto up_fail;
	}

	current_thread_info()->sysenter_return =
		VDSO32_SYMBOL(addr, SYSENTER_RETURN);

  up_fail:
	if (ret)
		current->mm->context.vdso = NULL;

	up_write(&mm->mmap_sem);
	if (ret < 0)
		ub_memory_uncharge(mm, PAGE_SIZE, flags, NULL);
err_charge:

	return ret;
}

/*
 * This is called when the thread calls exit().
 */
void exit_thread(void)
{
#if XTENSA_HAVE_COPROCESSORS
	coprocessor_release_all(current_thread_info());
#endif
}

/*
 * The interrupt handling path, implemented in terms of HV interrupt
 * emulation on TILE64 and TILEPro, and IPI hardware on TILE-Gx.
 */
void tile_dev_intr(struct pt_regs *regs, int intnum)
{
	int depth = __get_cpu_var(irq_depth)++;
	unsigned long original_irqs;
	unsigned long remaining_irqs;
	struct pt_regs *old_regs;

#if CHIP_HAS_IPI()
	/*
	 * Pending interrupts are listed in an SPR.  We might be
	 * nested, so be sure to only handle irqs that weren't already
	 * masked by a previous interrupt.  Then, mask out the ones
	 * we're going to handle.
	 */
	unsigned long masked = __insn_mfspr(SPR_IPI_MASK_K);
	original_irqs = __insn_mfspr(SPR_IPI_EVENT_K) & ~masked;
	__insn_mtspr(SPR_IPI_MASK_SET_K, original_irqs);
#else
	/*
	 * Hypervisor performs the equivalent of the Gx code above and
	 * then puts the pending interrupt mask into a system save reg
	 * for us to find.
	 */
	original_irqs = __insn_mfspr(SPR_SYSTEM_SAVE_K_3);
#endif
	remaining_irqs = original_irqs;

	/* Track time spent here in an interrupt context. */
	old_regs = set_irq_regs(regs);
	irq_enter();

#ifdef CONFIG_DEBUG_STACKOVERFLOW
	/* Debugging check for stack overflow: less than 1/8th stack free? */
	{
		long sp = stack_pointer - (long) current_thread_info();
		if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
			pr_emerg("tile_dev_intr: "
			       "stack overflow: %ld\n",
			       sp - sizeof(struct thread_info));
			dump_stack();
		}
	}
#endif
	while (remaining_irqs) {
		unsigned long irq = __ffs(remaining_irqs);
		remaining_irqs &= ~(1UL << irq);

		/* Count device irqs; Linux IPIs are counted elsewhere. */
		if (irq != IRQ_RESCHEDULE)
			__get_cpu_var(irq_stat).irq_dev_intr_count++;

		generic_handle_irq(irq);
	}

	/*
	 * If we weren't nested, turn on all enabled interrupts,
	 * including any that were reenabled during interrupt
	 * handling.
	 */
	if (depth == 0)
		unmask_irqs(~__get_cpu_var(irq_disable_mask));

	__get_cpu_var(irq_depth)--;

	/*
	 * Track time spent against the current process again and
	 * process any softirqs if they are waiting.
	 */
	irq_exit();
	set_irq_regs(old_regs);
}

/* {set, get}context() needed for 64-bit SparcLinux userland. */
asmlinkage void sparc64_set_context(struct pt_regs *regs)
{
	struct ucontext __user *ucp = (struct ucontext __user *)
		regs->u_regs[UREG_I0];
	mc_gregset_t __user *grp;
	unsigned long pc, npc, tstate;
	unsigned long fp, i7;
	unsigned char fenab;
	int err;

	flush_user_windows();
	if (get_thread_wsaved()					||
	    (((unsigned long)ucp) & (sizeof(unsigned long)-1))	||
	    (!__access_ok(ucp, sizeof(*ucp))))
		goto do_sigsegv;
	grp  = &ucp->uc_mcontext.mc_gregs;
	err  = __get_user(pc, &((*grp)[MC_PC]));
	err |= __get_user(npc, &((*grp)[MC_NPC]));
	if (err || ((pc | npc) & 3))
		goto do_sigsegv;
	if (regs->u_regs[UREG_I1]) {
		sigset_t set;

		if (_NSIG_WORDS == 1) {
			if (__get_user(set.sig[0], &ucp->uc_sigmask.sig[0]))
				goto do_sigsegv;
		} else {
			if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(sigset_t)))
				goto do_sigsegv;
		}
		sigdelsetmask(&set, ~_BLOCKABLE);
		spin_lock_irq(&current->sighand->siglock);
		current->blocked = set;
		recalc_sigpending();
		spin_unlock_irq(&current->sighand->siglock);
	}
	if (test_thread_flag(TIF_32BIT)) {
		pc &= 0xffffffff;
		npc &= 0xffffffff;
	}
	regs->tpc = pc;
	regs->tnpc = npc;
	err |= __get_user(regs->y, &((*grp)[MC_Y]));
	err |= __get_user(tstate, &((*grp)[MC_TSTATE]));
	regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
	regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
	err |= __get_user(regs->u_regs[UREG_G1], (&(*grp)[MC_G1]));
	err |= __get_user(regs->u_regs[UREG_G2], (&(*grp)[MC_G2]));
	err |= __get_user(regs->u_regs[UREG_G3], (&(*grp)[MC_G3]));
	err |= __get_user(regs->u_regs[UREG_G4], (&(*grp)[MC_G4]));
	err |= __get_user(regs->u_regs[UREG_G5], (&(*grp)[MC_G5]));
	err |= __get_user(regs->u_regs[UREG_G6], (&(*grp)[MC_G6]));

	/* Skip %g7 as that's the thread register in userspace.  */

	err |= __get_user(regs->u_regs[UREG_I0], (&(*grp)[MC_O0]));
	err |= __get_user(regs->u_regs[UREG_I1], (&(*grp)[MC_O1]));
	err |= __get_user(regs->u_regs[UREG_I2], (&(*grp)[MC_O2]));
	err |= __get_user(regs->u_regs[UREG_I3], (&(*grp)[MC_O3]));
	err |= __get_user(regs->u_regs[UREG_I4], (&(*grp)[MC_O4]));
	err |= __get_user(regs->u_regs[UREG_I5], (&(*grp)[MC_O5]));
	err |= __get_user(regs->u_regs[UREG_I6], (&(*grp)[MC_O6]));
	err |= __get_user(regs->u_regs[UREG_I7], (&(*grp)[MC_O7]));

	err |= __get_user(fp, &(ucp->uc_mcontext.mc_fp));
	err |= __get_user(i7, &(ucp->uc_mcontext.mc_i7));
	err |= __put_user(fp,
	      (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
	err |= __put_user(i7,
	      (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));

	err |= __get_user(fenab, &(ucp->uc_mcontext.mc_fpregs.mcfpu_enab));
	if (fenab) {
		unsigned long *fpregs = current_thread_info()->fpregs;
		unsigned long fprs;
		
		fprs_write(0);
		err |= __get_user(fprs, &(ucp->uc_mcontext.mc_fpregs.mcfpu_fprs));
		if (fprs & FPRS_DL)
			err |= copy_from_user(fpregs,
					      &(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs),
					      (sizeof(unsigned int) * 32));
		if (fprs & FPRS_DU)
			err |= copy_from_user(fpregs+16,
			 ((unsigned long __user *)&(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs))+16,
			 (sizeof(unsigned int) * 32));
		err |= __get_user(current_thread_info()->xfsr[0],
				  &(ucp->uc_mcontext.mc_fpregs.mcfpu_fsr));
		err |= __get_user(current_thread_info()->gsr[0],
				  &(ucp->uc_mcontext.mc_fpregs.mcfpu_gsr));
		regs->tstate &= ~TSTATE_PEF;
	}
	if (err)
		goto do_sigsegv;

	return;
do_sigsegv:
	force_sig(SIGSEGV, current);
}