Initial import

1 files changed, 1096 insertions, 0 deletions

diff --git a/arch/tile/kernel/hardwall.c b/arch/tile/kernel/hardwall.c
new file mode 100644
index 000000000..2fd1694ac
--- /dev/null
+++ b/arch/tile/kernel/hardwall.c
@@ -0,0 +1,1096 @@
+/*
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful, but
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ */
+
+#include <linux/fs.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/rwsem.h>
+#include <linux/kprobes.h>
+#include <linux/sched.h>
+#include <linux/hardirq.h>
+#include <linux/uaccess.h>
+#include <linux/smp.h>
+#include <linux/cdev.h>
+#include <linux/compat.h>
+#include <asm/hardwall.h>
+#include <asm/traps.h>
+#include <asm/siginfo.h>
+#include <asm/irq_regs.h>
+
+#include <arch/interrupts.h>
+#include <arch/spr_def.h>
+
+
+/*
+ * Implement a per-cpu "hardwall" resource class such as UDN or IPI.
+ * We use "hardwall" nomenclature throughout for historical reasons.
+ * The lock here controls access to the list data structure as well as
+ * to the items on the list.
+ */
+struct hardwall_type {
+	int index;
+	int is_xdn;
+	int is_idn;
+	int disabled;
+	const char *name;
+	struct list_head list;
+	spinlock_t lock;
+	struct proc_dir_entry *proc_dir;
+};
+
+enum hardwall_index {
+	HARDWALL_UDN = 0,
+#ifndef __tilepro__
+	HARDWALL_IDN = 1,
+	HARDWALL_IPI = 2,
+#endif
+	_HARDWALL_TYPES
+};
+
+static struct hardwall_type hardwall_types[] = {
+	{  /* user-space access to UDN */
+		0,
+		1,
+		0,
+		0,
+		"udn",
+		LIST_HEAD_INIT(hardwall_types[HARDWALL_UDN].list),
+		__SPIN_LOCK_UNLOCKED(hardwall_types[HARDWALL_UDN].lock),
+		NULL
+	},
+#ifndef __tilepro__
+	{  /* user-space access to IDN */
+		1,
+		1,
+		1,
+		1,  /* disabled pending hypervisor support */
+		"idn",
+		LIST_HEAD_INIT(hardwall_types[HARDWALL_IDN].list),
+		__SPIN_LOCK_UNLOCKED(hardwall_types[HARDWALL_IDN].lock),
+		NULL
+	},
+	{  /* access to user-space IPI */
+		2,
+		0,
+		0,
+		0,
+		"ipi",
+		LIST_HEAD_INIT(hardwall_types[HARDWALL_IPI].list),
+		__SPIN_LOCK_UNLOCKED(hardwall_types[HARDWALL_IPI].lock),
+		NULL
+	},
+#endif
+};
+
+/*
+ * This data structure tracks the cpu data, etc., associated
+ * one-to-one with a "struct file *" from opening a hardwall device file.
+ * Note that the file's private data points back to this structure.
+ */
+struct hardwall_info {
+	struct list_head list;             /* for hardwall_types.list */
+	struct list_head task_head;        /* head of tasks in this hardwall */
+	struct hardwall_type *type;        /* type of this resource */
+	struct cpumask cpumask;            /* cpus reserved */
+	int id;                            /* integer id for this hardwall */
+	int teardown_in_progress;          /* are we tearing this one down? */
+
+	/* Remaining fields only valid for user-network resources. */
+	int ulhc_x;                        /* upper left hand corner x coord */
+	int ulhc_y;                        /* upper left hand corner y coord */
+	int width;                         /* rectangle width */
+	int height;                        /* rectangle height */
+#if CHIP_HAS_REV1_XDN()
+	atomic_t xdn_pending_count;        /* cores in phase 1 of drain */
+#endif
+};
+
+
+/* /proc/tile/hardwall */
+static struct proc_dir_entry *hardwall_proc_dir;
+
+/* Functions to manage files in /proc/tile/hardwall. */
+static void hardwall_add_proc(struct hardwall_info *);
+static void hardwall_remove_proc(struct hardwall_info *);
+
+/* Allow disabling UDN access. */
+static int __init noudn(char *str)
+{
+	pr_info("User-space UDN access is disabled\n");
+	hardwall_types[HARDWALL_UDN].disabled = 1;
+	return 0;
+}
+early_param("noudn", noudn);
+
+#ifndef __tilepro__
+/* Allow disabling IDN access. */
+static int __init noidn(char *str)
+{
+	pr_info("User-space IDN access is disabled\n");
+	hardwall_types[HARDWALL_IDN].disabled = 1;
+	return 0;
+}
+early_param("noidn", noidn);
+
+/* Allow disabling IPI access. */
+static int __init noipi(char *str)
+{
+	pr_info("User-space IPI access is disabled\n");
+	hardwall_types[HARDWALL_IPI].disabled = 1;
+	return 0;
+}
+early_param("noipi", noipi);
+#endif
+
+
+/*
+ * Low-level primitives for UDN/IDN
+ */
+
+#ifdef __tilepro__
+#define mtspr_XDN(hwt, name, val) \
+	do { (void)(hwt); __insn_mtspr(SPR_UDN_##name, (val)); } while (0)
+#define mtspr_MPL_XDN(hwt, name, val) \
+	do { (void)(hwt); __insn_mtspr(SPR_MPL_UDN_##name, (val)); } while (0)
+#define mfspr_XDN(hwt, name) \
+	((void)(hwt), __insn_mfspr(SPR_UDN_##name))
+#else
+#define mtspr_XDN(hwt, name, val)					\
+	do {								\
+		if ((hwt)->is_idn)					\
+			__insn_mtspr(SPR_IDN_##name, (val));		\
+		else							\
+			__insn_mtspr(SPR_UDN_##name, (val));		\
+	} while (0)
+#define mtspr_MPL_XDN(hwt, name, val)					\
+	do {								\
+		if ((hwt)->is_idn)					\
+			__insn_mtspr(SPR_MPL_IDN_##name, (val));	\
+		else							\
+			__insn_mtspr(SPR_MPL_UDN_##name, (val));	\
+	} while (0)
+#define mfspr_XDN(hwt, name) \
+  ((hwt)->is_idn ? __insn_mfspr(SPR_IDN_##name) : __insn_mfspr(SPR_UDN_##name))
+#endif
+
+/* Set a CPU bit if the CPU is online. */
+#define cpu_online_set(cpu, dst) do { \
+	if (cpu_online(cpu))          \
+		cpumask_set_cpu(cpu, dst);    \
+} while (0)
+
+
+/* Does the given rectangle contain the given x,y coordinate? */
+static int contains(struct hardwall_info *r, int x, int y)
+{
+	return (x >= r->ulhc_x && x < r->ulhc_x + r->width) &&
+		(y >= r->ulhc_y && y < r->ulhc_y + r->height);
+}
+
+/* Compute the rectangle parameters and validate the cpumask. */
+static int check_rectangle(struct hardwall_info *r, struct cpumask *mask)
+{
+	int x, y, cpu, ulhc, lrhc;
+
+	/* The first cpu is the ULHC, the last the LRHC. */
+	ulhc = find_first_bit(cpumask_bits(mask), nr_cpumask_bits);
+	lrhc = find_last_bit(cpumask_bits(mask), nr_cpumask_bits);
+
+	/* Compute the rectangle attributes from the cpus. */
+	r->ulhc_x = cpu_x(ulhc);
+	r->ulhc_y = cpu_y(ulhc);
+	r->width = cpu_x(lrhc) - r->ulhc_x + 1;
+	r->height = cpu_y(lrhc) - r->ulhc_y + 1;
+
+	/* Width and height must be positive */
+	if (r->width <= 0 || r->height <= 0)
+		return -EINVAL;
+
+	/* Confirm that the cpumask is exactly the rectangle. */
+	for (y = 0, cpu = 0; y < smp_height; ++y)
+		for (x = 0; x < smp_width; ++x, ++cpu)
+			if (cpumask_test_cpu(cpu, mask) != contains(r, x, y))
+				return -EINVAL;
+
+	/*
+	 * Note that offline cpus can't be drained when this user network
+	 * rectangle eventually closes.  We used to detect this
+	 * situation and print a warning, but it annoyed users and
+	 * they ignored it anyway, so now we just return without a
+	 * warning.
+	 */
+	return 0;
+}
+
+/*
+ * Hardware management of hardwall setup, teardown, trapping,
+ * and enabling/disabling PL0 access to the networks.
+ */
+
+/* Bit field values to mask together for writes to SPR_XDN_DIRECTION_PROTECT */
+enum direction_protect {
+	N_PROTECT = (1 << 0),
+	E_PROTECT = (1 << 1),
+	S_PROTECT = (1 << 2),
+	W_PROTECT = (1 << 3),
+	C_PROTECT = (1 << 4),
+};
+
+static inline int xdn_which_interrupt(struct hardwall_type *hwt)
+{
+#ifndef __tilepro__
+	if (hwt->is_idn)
+		return INT_IDN_FIREWALL;
+#endif
+	return INT_UDN_FIREWALL;
+}
+
+static void enable_firewall_interrupts(struct hardwall_type *hwt)
+{
+	arch_local_irq_unmask_now(xdn_which_interrupt(hwt));
+}
+
+static void disable_firewall_interrupts(struct hardwall_type *hwt)
+{
+	arch_local_irq_mask_now(xdn_which_interrupt(hwt));
+}
+
+/* Set up hardwall on this cpu based on the passed hardwall_info. */
+static void hardwall_setup_func(void *info)
+{
+	struct hardwall_info *r = info;
+	struct hardwall_type *hwt = r->type;
+
+	int cpu = smp_processor_id();  /* on_each_cpu disables preemption */
+	int x = cpu_x(cpu);
+	int y = cpu_y(cpu);
+	int bits = 0;
+	if (x == r->ulhc_x)
+		bits |= W_PROTECT;
+	if (x == r->ulhc_x + r->width - 1)
+		bits |= E_PROTECT;
+	if (y == r->ulhc_y)
+		bits |= N_PROTECT;
+	if (y == r->ulhc_y + r->height - 1)
+		bits |= S_PROTECT;
+	BUG_ON(bits == 0);
+	mtspr_XDN(hwt, DIRECTION_PROTECT, bits);
+	enable_firewall_interrupts(hwt);
+}
+
+/* Set up all cpus on edge of rectangle to enable/disable hardwall SPRs. */
+static void hardwall_protect_rectangle(struct hardwall_info *r)
+{
+	int x, y, cpu, delta;
+	struct cpumask rect_cpus;
+
+	cpumask_clear(&rect_cpus);
+
+	/* First include the top and bottom edges */
+	cpu = r->ulhc_y * smp_width + r->ulhc_x;
+	delta = (r->height - 1) * smp_width;
+	for (x = 0; x < r->width; ++x, ++cpu) {
+		cpu_online_set(cpu, &rect_cpus);
+		cpu_online_set(cpu + delta, &rect_cpus);
+	}
+
+	/* Then the left and right edges */
+	cpu -= r->width;
+	delta = r->width - 1;
+	for (y = 0; y < r->height; ++y, cpu += smp_width) {
+		cpu_online_set(cpu, &rect_cpus);
+		cpu_online_set(cpu + delta, &rect_cpus);
+	}
+
+	/* Then tell all the cpus to set up their protection SPR */
+	on_each_cpu_mask(&rect_cpus, hardwall_setup_func, r, 1);
+}
+
+/* Entered from INT_xDN_FIREWALL interrupt vector with irqs disabled. */
+void __kprobes do_hardwall_trap(struct pt_regs* regs, int fault_num)
+{
+	struct hardwall_info *rect;
+	struct hardwall_type *hwt;
+	struct task_struct *p;
+	struct siginfo info;
+	int cpu = smp_processor_id();
+	int found_processes;
+	struct pt_regs *old_regs = set_irq_regs(regs);
+
+	irq_enter();
+
+	/* Figure out which network trapped. */
+	switch (fault_num) {
+#ifndef __tilepro__
+	case INT_IDN_FIREWALL:
+		hwt = &hardwall_types[HARDWALL_IDN];
+		break;
+#endif
+	case INT_UDN_FIREWALL:
+		hwt = &hardwall_types[HARDWALL_UDN];
+		break;
+	default:
+		BUG();
+	}
+	BUG_ON(hwt->disabled);
+
+	/* This tile trapped a network access; find the rectangle. */
+	spin_lock(&hwt->lock);
+	list_for_each_entry(rect, &hwt->list, list) {
+		if (cpumask_test_cpu(cpu, &rect->cpumask))
+			break;
+	}
+
+	/*
+	 * It shouldn't be possible not to find this cpu on the
+	 * rectangle list, since only cpus in rectangles get hardwalled.
+	 * The hardwall is only removed after the user network is drained.
+	 */
+	BUG_ON(&rect->list == &hwt->list);
+
+	/*
+	 * If we already started teardown on this hardwall, don't worry;
+	 * the abort signal has been sent and we are just waiting for things
+	 * to quiesce.
+	 */
+	if (rect->teardown_in_progress) {
+		pr_notice("cpu %d: detected %s hardwall violation %#lx while teardown already in progress\n",
+			  cpu, hwt->name,
+			  (long)mfspr_XDN(hwt, DIRECTION_PROTECT));
+		goto done;
+	}
+
+	/*
+	 * Kill off any process that is activated in this rectangle.
+	 * We bypass security to deliver the signal, since it must be
+	 * one of the activated processes that generated the user network
+	 * message that caused this trap, and all the activated
+	 * processes shared a single open file so are pretty tightly
+	 * bound together from a security point of view to begin with.
+	 */
+	rect->teardown_in_progress = 1;
+	wmb(); /* Ensure visibility of rectangle before notifying processes. */
+	pr_notice("cpu %d: detected %s hardwall violation %#lx...\n",
+		  cpu, hwt->name, (long)mfspr_XDN(hwt, DIRECTION_PROTECT));
+	info.si_signo = SIGILL;
+	info.si_errno = 0;
+	info.si_code = ILL_HARDWALL;
+	found_processes = 0;
+	list_for_each_entry(p, &rect->task_head,
+			    thread.hardwall[hwt->index].list) {
+		BUG_ON(p->thread.hardwall[hwt->index].info != rect);
+		if (!(p->flags & PF_EXITING)) {
+			found_processes = 1;
+			pr_notice("hardwall: killing %d\n", p->pid);
+			do_send_sig_info(info.si_signo, &info, p, false);
+		}
+	}
+	if (!found_processes)
+		pr_notice("hardwall: no associated processes!\n");
+
+ done:
+	spin_unlock(&hwt->lock);
+
+	/*
+	 * We have to disable firewall interrupts now, or else when we
+	 * return from this handler, we will simply re-interrupt back to
+	 * it.  However, we can't clear the protection bits, since we
+	 * haven't yet drained the network, and that would allow packets
+	 * to cross out of the hardwall region.
+	 */
+	disable_firewall_interrupts(hwt);
+
+	irq_exit();
+	set_irq_regs(old_regs);
+}
+
+/* Allow access from user space to the user network. */
+void grant_hardwall_mpls(struct hardwall_type *hwt)
+{
+#ifndef __tilepro__
+	if (!hwt->is_xdn) {
+		__insn_mtspr(SPR_MPL_IPI_0_SET_0, 1);
+		return;
+	}
+#endif
+	mtspr_MPL_XDN(hwt, ACCESS_SET_0, 1);
+	mtspr_MPL_XDN(hwt, AVAIL_SET_0, 1);
+	mtspr_MPL_XDN(hwt, COMPLETE_SET_0, 1);
+	mtspr_MPL_XDN(hwt, TIMER_SET_0, 1);
+#if !CHIP_HAS_REV1_XDN()
+	mtspr_MPL_XDN(hwt, REFILL_SET_0, 1);
+	mtspr_MPL_XDN(hwt, CA_SET_0, 1);
+#endif
+}
+
+/* Deny access from user space to the user network. */
+void restrict_hardwall_mpls(struct hardwall_type *hwt)
+{
+#ifndef __tilepro__
+	if (!hwt->is_xdn) {
+		__insn_mtspr(SPR_MPL_IPI_0_SET_1, 1);
+		return;
+	}
+#endif
+	mtspr_MPL_XDN(hwt, ACCESS_SET_1, 1);
+	mtspr_MPL_XDN(hwt, AVAIL_SET_1, 1);
+	mtspr_MPL_XDN(hwt, COMPLETE_SET_1, 1);
+	mtspr_MPL_XDN(hwt, TIMER_SET_1, 1);
+#if !CHIP_HAS_REV1_XDN()
+	mtspr_MPL_XDN(hwt, REFILL_SET_1, 1);
+	mtspr_MPL_XDN(hwt, CA_SET_1, 1);
+#endif
+}
+
+/* Restrict or deny as necessary for the task we're switching to. */
+void hardwall_switch_tasks(struct task_struct *prev,
+			   struct task_struct *next)
+{
+	int i;
+	for (i = 0; i < HARDWALL_TYPES; ++i) {
+		if (prev->thread.hardwall[i].info != NULL) {
+			if (next->thread.hardwall[i].info == NULL)
+				restrict_hardwall_mpls(&hardwall_types[i]);
+		} else if (next->thread.hardwall[i].info != NULL) {
+			grant_hardwall_mpls(&hardwall_types[i]);
+		}
+	}
+}
+
+/* Does this task have the right to IPI the given cpu? */
+int hardwall_ipi_valid(int cpu)
+{
+#ifdef __tilegx__
+	struct hardwall_info *info =
+		current->thread.hardwall[HARDWALL_IPI].info;
+	return info && cpumask_test_cpu(cpu, &info->cpumask);
+#else
+	return 0;
+#endif
+}
+
+/*
+ * Code to create, activate, deactivate, and destroy hardwall resources.
+ */
+
+/* Create a hardwall for the given resource */
+static struct hardwall_info *hardwall_create(struct hardwall_type *hwt,
+					     size_t size,
+					     const unsigned char __user *bits)
+{
+	struct hardwall_info *iter, *info;
+	struct cpumask mask;
+	unsigned long flags;
+	int rc;
+
+	/* Reject crazy sizes out of hand, a la sys_mbind(). */
+	if (size > PAGE_SIZE)
+		return ERR_PTR(-EINVAL);
+
+	/* Copy whatever fits into a cpumask. */
+	if (copy_from_user(&mask, bits, min(sizeof(struct cpumask), size)))
+		return ERR_PTR(-EFAULT);
+
+	/*
+	 * If the size was short, clear the rest of the mask;
+	 * otherwise validate that the rest of the user mask was zero
+	 * (we don't try hard to be efficient when validating huge masks).
+	 */
+	if (size < sizeof(struct cpumask)) {
+		memset((char *)&mask + size, 0, sizeof(struct cpumask) - size);
+	} else if (size > sizeof(struct cpumask)) {
+		size_t i;
+		for (i = sizeof(struct cpumask); i < size; ++i) {
+			char c;
+			if (get_user(c, &bits[i]))
+				return ERR_PTR(-EFAULT);
+			if (c)
+				return ERR_PTR(-EINVAL);
+		}
+	}
+
+	/* Allocate a new hardwall_info optimistically. */
+	info = kmalloc(sizeof(struct hardwall_info),
+			GFP_KERNEL | __GFP_ZERO);
+	if (info == NULL)
+		return ERR_PTR(-ENOMEM);
+	INIT_LIST_HEAD(&info->task_head);
+	info->type = hwt;
+
+	/* Compute the rectangle size and validate that it's plausible. */
+	cpumask_copy(&info->cpumask, &mask);
+	info->id = find_first_bit(cpumask_bits(&mask), nr_cpumask_bits);
+	if (hwt->is_xdn) {
+		rc = check_rectangle(info, &mask);
+		if (rc != 0) {
+			kfree(info);
+			return ERR_PTR(rc);
+		}
+	}
+
+	/*
+	 * Eliminate cpus that are not part of this Linux client.
+	 * Note that this allows for configurations that we might not want to
+	 * support, such as one client on every even cpu, another client on
+	 * every odd cpu.
+	 */
+	cpumask_and(&info->cpumask, &info->cpumask, cpu_online_mask);
+
+	/* Confirm it doesn't overlap and add it to the list. */
+	spin_lock_irqsave(&hwt->lock, flags);
+	list_for_each_entry(iter, &hwt->list, list) {
+		if (cpumask_intersects(&iter->cpumask, &info->cpumask)) {
+			spin_unlock_irqrestore(&hwt->lock, flags);
+			kfree(info);
+			return ERR_PTR(-EBUSY);
+		}
+	}
+	list_add_tail(&info->list, &hwt->list);
+	spin_unlock_irqrestore(&hwt->lock, flags);
+
+	/* Set up appropriate hardwalling on all affected cpus. */
+	if (hwt->is_xdn)
+		hardwall_protect_rectangle(info);
+
+	/* Create a /proc/tile/hardwall entry. */
+	hardwall_add_proc(info);
+
+	return info;
+}
+
+/* Activate a given hardwall on this cpu for this process. */
+static int hardwall_activate(struct hardwall_info *info)
+{
+	int cpu;
+	unsigned long flags;
+	struct task_struct *p = current;
+	struct thread_struct *ts = &p->thread;
+	struct hardwall_type *hwt;
+
+	/* Require a hardwall. */
+	if (info == NULL)
+		return -ENODATA;
+
+	/* Not allowed to activate a hardwall that is being torn down. */
+	if (info->teardown_in_progress)
+		return -EINVAL;
+
+	/*
+	 * Get our affinity; if we're not bound to this tile uniquely,
+	 * we can't access the network registers.
+	 */
+	if (cpumask_weight(&p->cpus_allowed) != 1)
+		return -EPERM;
+
+	/* Make sure we are bound to a cpu assigned to this resource. */
+	cpu = smp_processor_id();
+	BUG_ON(cpumask_first(&p->cpus_allowed) != cpu);
+	if (!cpumask_test_cpu(cpu, &info->cpumask))
+		return -EINVAL;
+
+	/* If we are already bound to this hardwall, it's a no-op. */
+	hwt = info->type;
+	if (ts->hardwall[hwt->index].info) {
+		BUG_ON(ts->hardwall[hwt->index].info != info);
+		return 0;
+	}
+
+	/* Success!  This process gets to use the resource on this cpu. */
+	ts->hardwall[hwt->index].info = info;
+	spin_lock_irqsave(&hwt->lock, flags);
+	list_add(&ts->hardwall[hwt->index].list, &info->task_head);
+	spin_unlock_irqrestore(&hwt->lock, flags);
+	grant_hardwall_mpls(hwt);
+	printk(KERN_DEBUG "Pid %d (%s) activated for %s hardwall: cpu %d\n",
+	       p->pid, p->comm, hwt->name, cpu);
+	return 0;
+}
+
+/*
+ * Deactivate a task's hardwall.  Must hold lock for hardwall_type.
+ * This method may be called from exit_thread(), so we don't want to
+ * rely on too many fields of struct task_struct still being valid.
+ * We assume the cpus_allowed, pid, and comm fields are still valid.
+ */
+static void _hardwall_deactivate(struct hardwall_type *hwt,
+				 struct task_struct *task)
+{
+	struct thread_struct *ts = &task->thread;
+
+	if (cpumask_weight(&task->cpus_allowed) != 1) {
+		pr_err("pid %d (%s) releasing %s hardwall with an affinity mask containing %d cpus!\n",
+		       task->pid, task->comm, hwt->name,
+		       cpumask_weight(&task->cpus_allowed));
+		BUG();
+	}
+
+	BUG_ON(ts->hardwall[hwt->index].info == NULL);
+	ts->hardwall[hwt->index].info = NULL;
+	list_del(&ts->hardwall[hwt->index].list);
+	if (task == current)
+		restrict_hardwall_mpls(hwt);
+}
+
+/* Deactivate a task's hardwall. */
+static int hardwall_deactivate(struct hardwall_type *hwt,
+			       struct task_struct *task)
+{
+	unsigned long flags;
+	int activated;
+
+	spin_lock_irqsave(&hwt->lock, flags);
+	activated = (task->thread.hardwall[hwt->index].info != NULL);
+	if (activated)
+		_hardwall_deactivate(hwt, task);
+	spin_unlock_irqrestore(&hwt->lock, flags);
+
+	if (!activated)
+		return -EINVAL;
+
+	printk(KERN_DEBUG "Pid %d (%s) deactivated for %s hardwall: cpu %d\n",
+	       task->pid, task->comm, hwt->name, raw_smp_processor_id());
+	return 0;
+}
+
+void hardwall_deactivate_all(struct task_struct *task)
+{
+	int i;
+	for (i = 0; i < HARDWALL_TYPES; ++i)
+		if (task->thread.hardwall[i].info)
+			hardwall_deactivate(&hardwall_types[i], task);
+}
+
+/* Stop the switch before draining the network. */
+static void stop_xdn_switch(void *arg)
+{
+#if !CHIP_HAS_REV1_XDN()
+	/* Freeze the switch and the demux. */
+	__insn_mtspr(SPR_UDN_SP_FREEZE,
+		     SPR_UDN_SP_FREEZE__SP_FRZ_MASK |
+		     SPR_UDN_SP_FREEZE__DEMUX_FRZ_MASK |
+		     SPR_UDN_SP_FREEZE__NON_DEST_EXT_MASK);
+#else
+	/*
+	 * Drop all packets bound for the core or off the edge.
+	 * We rely on the normal hardwall protection setup code
+	 * to have set the low four bits to trigger firewall interrupts,
+	 * and shift those bits up to trigger "drop on send" semantics,
+	 * plus adding "drop on send to core" for all switches.
+	 * In practice it seems the switches latch the DIRECTION_PROTECT
+	 * SPR so they won't start dropping if they're already
+	 * delivering the last message to the core, but it doesn't
+	 * hurt to enable it here.
+	 */
+	struct hardwall_type *hwt = arg;
+	unsigned long protect = mfspr_XDN(hwt, DIRECTION_PROTECT);
+	mtspr_XDN(hwt, DIRECTION_PROTECT, (protect | C_PROTECT) << 5);
+#endif
+}
+
+static void empty_xdn_demuxes(struct hardwall_type *hwt)
+{
+#ifndef __tilepro__
+	if (hwt->is_idn) {
+		while (__insn_mfspr(SPR_IDN_DATA_AVAIL) & (1 << 0))
+			(void) __tile_idn0_receive();
+		while (__insn_mfspr(SPR_IDN_DATA_AVAIL) & (1 << 1))
+			(void) __tile_idn1_receive();
+		return;
+	}
+#endif
+	while (__insn_mfspr(SPR_UDN_DATA_AVAIL) & (1 << 0))
+		(void) __tile_udn0_receive();
+	while (__insn_mfspr(SPR_UDN_DATA_AVAIL) & (1 << 1))
+		(void) __tile_udn1_receive();
+	while (__insn_mfspr(SPR_UDN_DATA_AVAIL) & (1 << 2))
+		(void) __tile_udn2_receive();
+	while (__insn_mfspr(SPR_UDN_DATA_AVAIL) & (1 << 3))
+		(void) __tile_udn3_receive();
+}
+
+/* Drain all the state from a stopped switch. */
+static void drain_xdn_switch(void *arg)
+{
+	struct hardwall_info *info = arg;
+	struct hardwall_type *hwt = info->type;
+
+#if CHIP_HAS_REV1_XDN()
+	/*
+	 * The switches have been configured to drop any messages
+	 * destined for cores (or off the edge of the rectangle).
+	 * But the current message may continue to be delivered,
+	 * so we wait until all the cores have finished any pending
+	 * messages before we stop draining.
+	 */
+	int pending = mfspr_XDN(hwt, PENDING);
+	while (pending--) {
+		empty_xdn_demuxes(hwt);
+		if (hwt->is_idn)
+			__tile_idn_send(0);
+		else
+			__tile_udn_send(0);
+	}
+	atomic_dec(&info->xdn_pending_count);
+	while (atomic_read(&info->xdn_pending_count))
+		empty_xdn_demuxes(hwt);
+#else
+	int i;
+	int from_tile_words, ca_count;
+
+	/* Empty out the 5 switch point fifos. */
+	for (i = 0; i < 5; i++) {
+		int words, j;
+		__insn_mtspr(SPR_UDN_SP_FIFO_SEL, i);
+		words = __insn_mfspr(SPR_UDN_SP_STATE) & 0xF;
+		for (j = 0; j < words; j++)
+			(void) __insn_mfspr(SPR_UDN_SP_FIFO_DATA);
+		BUG_ON((__insn_mfspr(SPR_UDN_SP_STATE) & 0xF) != 0);
+	}
+
+	/* Dump out the 3 word fifo at top. */
+	from_tile_words = (__insn_mfspr(SPR_UDN_DEMUX_STATUS) >> 10) & 0x3;
+	for (i = 0; i < from_tile_words; i++)
+		(void) __insn_mfspr(SPR_UDN_DEMUX_WRITE_FIFO);
+
+	/* Empty out demuxes. */
+	empty_xdn_demuxes(hwt);
+
+	/* Empty out catch all. */
+	ca_count = __insn_mfspr(SPR_UDN_DEMUX_CA_COUNT);
+	for (i = 0; i < ca_count; i++)
+		(void) __insn_mfspr(SPR_UDN_CA_DATA);
+	BUG_ON(__insn_mfspr(SPR_UDN_DEMUX_CA_COUNT) != 0);
+
+	/* Clear demux logic. */
+	__insn_mtspr(SPR_UDN_DEMUX_CTL, 1);
+
+	/*
+	 * Write switch state; experimentation indicates that 0xc3000
+	 * is an idle switch point.
+	 */
+	for (i = 0; i < 5; i++) {
+		__insn_mtspr(SPR_UDN_SP_FIFO_SEL, i);
+		__insn_mtspr(SPR_UDN_SP_STATE, 0xc3000);
+	}
+#endif
+}
+
+/* Reset random XDN state registers at boot up and during hardwall teardown. */
+static void reset_xdn_network_state(struct hardwall_type *hwt)
+{
+	if (hwt->disabled)
+		return;
+
+	/* Clear out other random registers so we have a clean slate. */
+	mtspr_XDN(hwt, DIRECTION_PROTECT, 0);
+	mtspr_XDN(hwt, AVAIL_EN, 0);
+	mtspr_XDN(hwt, DEADLOCK_TIMEOUT, 0);
+
+#if !CHIP_HAS_REV1_XDN()
+	/* Reset UDN coordinates to their standard value */
+	{
+		unsigned int cpu = smp_processor_id();
+		unsigned int x = cpu_x(cpu);
+		unsigned int y = cpu_y(cpu);
+		__insn_mtspr(SPR_UDN_TILE_COORD, (x << 18) | (y << 7));
+	}
+
+	/* Set demux tags to predefined values and enable them. */
+	__insn_mtspr(SPR_UDN_TAG_VALID, 0xf);
+	__insn_mtspr(SPR_UDN_TAG_0, (1 << 0));
+	__insn_mtspr(SPR_UDN_TAG_1, (1 << 1));
+	__insn_mtspr(SPR_UDN_TAG_2, (1 << 2));
+	__insn_mtspr(SPR_UDN_TAG_3, (1 << 3));
+
+	/* Set other rev0 random registers to a clean state. */
+	__insn_mtspr(SPR_UDN_REFILL_EN, 0);
+	__insn_mtspr(SPR_UDN_DEMUX_QUEUE_SEL, 0);
+	__insn_mtspr(SPR_UDN_SP_FIFO_SEL, 0);
+
+	/* Start the switch and demux. */
+	__insn_mtspr(SPR_UDN_SP_FREEZE, 0);
+#endif
+}
+
+void reset_network_state(void)
+{
+	reset_xdn_network_state(&hardwall_types[HARDWALL_UDN]);
+#ifndef __tilepro__
+	reset_xdn_network_state(&hardwall_types[HARDWALL_IDN]);
+#endif
+}
+
+/* Restart an XDN switch after draining. */
+static void restart_xdn_switch(void *arg)
+{
+	struct hardwall_type *hwt = arg;
+
+#if CHIP_HAS_REV1_XDN()
+	/* One last drain step to avoid races with injection and draining. */
+	empty_xdn_demuxes(hwt);
+#endif
+
+	reset_xdn_network_state(hwt);
+
+	/* Disable firewall interrupts. */
+	disable_firewall_interrupts(hwt);
+}
+
+/* Last reference to a hardwall is gone, so clear the network. */
+static void hardwall_destroy(struct hardwall_info *info)
+{
+	struct task_struct *task;
+	struct hardwall_type *hwt;
+	unsigned long flags;
+
+	/* Make sure this file actually represents a hardwall. */
+	if (info == NULL)
+		return;
+
+	/*
+	 * Deactivate any remaining tasks.  It's possible to race with
+	 * some other thread that is exiting and hasn't yet called
+	 * deactivate (when freeing its thread_info), so we carefully
+	 * deactivate any remaining tasks before freeing the
+	 * hardwall_info object itself.
+	 */
+	hwt = info->type;
+	info->teardown_in_progress = 1;
+	spin_lock_irqsave(&hwt->lock, flags);
+	list_for_each_entry(task, &info->task_head,
+			    thread.hardwall[hwt->index].list)
+		_hardwall_deactivate(hwt, task);
+	spin_unlock_irqrestore(&hwt->lock, flags);
+
+	if (hwt->is_xdn) {
+		/* Configure the switches for draining the user network. */
+		printk(KERN_DEBUG
+		       "Clearing %s hardwall rectangle %dx%d %d,%d\n",
+		       hwt->name, info->width, info->height,
+		       info->ulhc_x, info->ulhc_y);
+		on_each_cpu_mask(&info->cpumask, stop_xdn_switch, hwt, 1);
+
+		/* Drain the network. */
+#if CHIP_HAS_REV1_XDN()
+		atomic_set(&info->xdn_pending_count,
+			   cpumask_weight(&info->cpumask));
+		on_each_cpu_mask(&info->cpumask, drain_xdn_switch, info, 0);
+#else
+		on_each_cpu_mask(&info->cpumask, drain_xdn_switch, info, 1);
+#endif
+
+		/* Restart switch and disable firewall. */
+		on_each_cpu_mask(&info->cpumask, restart_xdn_switch, hwt, 1);
+	}
+
+	/* Remove the /proc/tile/hardwall entry. */
+	hardwall_remove_proc(info);
+
+	/* Now free the hardwall from the list. */
+	spin_lock_irqsave(&hwt->lock, flags);
+	BUG_ON(!list_empty(&info->task_head));
+	list_del(&info->list);
+	spin_unlock_irqrestore(&hwt->lock, flags);
+	kfree(info);
+}
+
+
+static int hardwall_proc_show(struct seq_file *sf, void *v)
+{
+	struct hardwall_info *info = sf->private;
+
+	seq_printf(sf, "%*pbl\n", cpumask_pr_args(&info->cpumask));
+	return 0;
+}
+
+static int hardwall_proc_open(struct inode *inode,
+			      struct file *file)
+{
+	return single_open(file, hardwall_proc_show, PDE_DATA(inode));
+}
+
+static const struct file_operations hardwall_proc_fops = {
+	.open		= hardwall_proc_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static void hardwall_add_proc(struct hardwall_info *info)
+{
+	char buf[64];
+	snprintf(buf, sizeof(buf), "%d", info->id);
+	proc_create_data(buf, 0444, info->type->proc_dir,
+			 &hardwall_proc_fops, info);
+}
+
+static void hardwall_remove_proc(struct hardwall_info *info)
+{
+	char buf[64];
+	snprintf(buf, sizeof(buf), "%d", info->id);
+	remove_proc_entry(buf, info->type->proc_dir);
+}
+
+int proc_pid_hardwall(struct seq_file *m, struct pid_namespace *ns,
+		      struct pid *pid, struct task_struct *task)
+{
+	int i;
+	int n = 0;
+	for (i = 0; i < HARDWALL_TYPES; ++i) {
+		struct hardwall_info *info = task->thread.hardwall[i].info;
+		if (info)
+			seq_printf(m, "%s: %d\n", info->type->name, info->id);
+	}
+	return n;
+}
+
+void proc_tile_hardwall_init(struct proc_dir_entry *root)
+{
+	int i;
+	for (i = 0; i < HARDWALL_TYPES; ++i) {
+		struct hardwall_type *hwt = &hardwall_types[i];
+		if (hwt->disabled)
+			continue;
+		if (hardwall_proc_dir == NULL)
+			hardwall_proc_dir = proc_mkdir("hardwall", root);
+		hwt->proc_dir = proc_mkdir(hwt->name, hardwall_proc_dir);
+	}
+}
+
+
+/*
+ * Character device support via ioctl/close.
+ */
+
+static long hardwall_ioctl(struct file *file, unsigned int a, unsigned long b)
+{
+	struct hardwall_info *info = file->private_data;
+	int minor = iminor(file->f_mapping->host);
+	struct hardwall_type* hwt;
+
+	if (_IOC_TYPE(a) != HARDWALL_IOCTL_BASE)
+		return -EINVAL;
+
+	BUILD_BUG_ON(HARDWALL_TYPES != _HARDWALL_TYPES);
+	BUILD_BUG_ON(HARDWALL_TYPES !=
+		     sizeof(hardwall_types)/sizeof(hardwall_types[0]));
+
+	if (minor < 0 || minor >= HARDWALL_TYPES)
+		return -EINVAL;
+	hwt = &hardwall_types[minor];
+	WARN_ON(info && hwt != info->type);
+
+	switch (_IOC_NR(a)) {
+	case _HARDWALL_CREATE:
+		if (hwt->disabled)
+			return -ENOSYS;
+		if (info != NULL)
+			return -EALREADY;
+		info = hardwall_create(hwt, _IOC_SIZE(a),
+				       (const unsigned char __user *)b);
+		if (IS_ERR(info))
+			return PTR_ERR(info);
+		file->private_data = info;
+		return 0;
+
+	case _HARDWALL_ACTIVATE:
+		return hardwall_activate(info);
+
+	case _HARDWALL_DEACTIVATE:
+		if (current->thread.hardwall[hwt->index].info != info)
+			return -EINVAL;
+		return hardwall_deactivate(hwt, current);
+
+	case _HARDWALL_GET_ID:
+		return info ? info->id : -EINVAL;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+#ifdef CONFIG_COMPAT
+static long hardwall_compat_ioctl(struct file *file,
+				  unsigned int a, unsigned long b)
+{
+	/* Sign-extend the argument so it can be used as a pointer. */
+	return hardwall_ioctl(file, a, (unsigned long)compat_ptr(b));
+}
+#endif
+
+/* The user process closed the file; revoke access to user networks. */
+static int hardwall_flush(struct file *file, fl_owner_t owner)
+{
+	struct hardwall_info *info = file->private_data;
+	struct task_struct *task, *tmp;
+	unsigned long flags;
+
+	if (info) {
+		/*
+		 * NOTE: if multiple threads are activated on this hardwall
+		 * file, the other threads will continue having access to the
+		 * user network until they are context-switched out and back
+		 * in again.
+		 *
+		 * NOTE: A NULL files pointer means the task is being torn
+		 * down, so in that case we also deactivate it.
+		 */
+		struct hardwall_type *hwt = info->type;
+		spin_lock_irqsave(&hwt->lock, flags);
+		list_for_each_entry_safe(task, tmp, &info->task_head,
+					 thread.hardwall[hwt->index].list) {
+			if (task->files == owner || task->files == NULL)
+				_hardwall_deactivate(hwt, task);
+		}
+		spin_unlock_irqrestore(&hwt->lock, flags);
+	}
+
+	return 0;
+}
+
+/* This hardwall is gone, so destroy it. */
+static int hardwall_release(struct inode *inode, struct file *file)
+{
+	hardwall_destroy(file->private_data);
+	return 0;
+}
+
+static const struct file_operations dev_hardwall_fops = {
+	.open           = nonseekable_open,
+	.unlocked_ioctl = hardwall_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl   = hardwall_compat_ioctl,
+#endif
+	.flush          = hardwall_flush,
+	.release        = hardwall_release,
+};
+
+static struct cdev hardwall_dev;
+
+static int __init dev_hardwall_init(void)
+{
+	int rc;
+	dev_t dev;
+
+	rc = alloc_chrdev_region(&dev, 0, HARDWALL_TYPES, "hardwall");
+	if (rc < 0)
+		return rc;
+	cdev_init(&hardwall_dev, &dev_hardwall_fops);
+	rc = cdev_add(&hardwall_dev, dev, HARDWALL_TYPES);
+	if (rc < 0)
+		return rc;
+
+	return 0;
+}
+late_initcall(dev_hardwall_init);