- 根目录:
- arch
- tile
- kernel
- hardwall.c
/*
* 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>
/*
* This data structure tracks the rectangle data, etc., associated
* one-to-one with a "struct file *" from opening HARDWALL_FILE.
* Note that the file's private data points back to this structure.
*/
struct hardwall_info {
struct list_head list; /* "rectangles" list */
struct list_head task_head; /* head of tasks in this hardwall */
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 */
int teardown_in_progress; /* are we tearing this one down? */
};
/* Currently allocated hardwall rectangles */
static LIST_HEAD(rectangles);
/*
* Guard changes to the hardwall data structures.
* This could be finer grained (e.g. one lock for the list of hardwall
* rectangles, then separate embedded locks for each one's list of tasks),
* but there are subtle correctness issues when trying to start with
* a task's "hardwall" pointer and lock the correct rectangle's embedded
* lock in the presence of a simultaneous deactivation, so it seems
* easier to have a single lock, given that none of these data
* structures are touched very frequently during normal operation.
*/
static DEFINE_SPINLOCK(hardwall_lock);
/* Allow disabling UDN access. */
static int udn_disabled;
static int __init noudn(char *str)
{
pr_info("User-space UDN access is disabled\n");
udn_disabled = 1;
return 0;
}
early_param("noudn", noudn);
/*
* Low-level primitives
*/
/* 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 setup_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 UDN
* 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;
}
/* Do the two given rectangles overlap on any cpu? */
static int overlaps(struct hardwall_info *a, struct hardwall_info *b)
{
return a->ulhc_x + a->width > b->ulhc_x && /* A not to the left */
b->ulhc_x + b->width > a->ulhc_x && /* B not to the left */
a->ulhc_y + a->height > b->ulhc_y && /* A not above */
b->ulhc_y + b->height > a->ulhc_y; /* B not above */
}
/*
* 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)
};
static void enable_firewall_interrupts(void)
{
arch_local_irq_unmask_now(INT_UDN_FIREWALL);
}
static void disable_firewall_interrupts(void)
{
arch_local_irq_mask_now(INT_UDN_FIREWALL);
}
/* Set up hardwall on this cpu based on the passed hardwall_info. */
static void hardwall_setup_ipi_func(void *info)
{
struct hardwall_info *r = info;
int cpu = smp_processor_id();
int x = cpu % smp_width;
int y = cpu / smp_width;
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);
__insn_mtspr(SPR_UDN_DIRECTION_PROTECT, bits);
enable_firewall_interrupts();
}
/* Set up all cpus on edge of rectangle to enable/disable hardwall SPRs. */
static void hardwall_setup(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_ipi_func, r, 1);
}
void __kprobes do_hardwall_trap(struct pt_regs* regs, int fault_num)
{
struct hardwall_info *rect;
struct task_struct *p;
struct siginfo info;
int x, y;
int cpu = smp_processor_id();
int found_processes;
unsigned long flags;
struct pt_regs *old_regs = set_irq_regs(regs);
irq_enter();
/* This tile trapped a network access; find the rectangle. */
x = cpu % smp_width;
y = cpu / smp_width;
spin_lock_irqsave(&hardwall_lock, flags);
list_for_each_entry(rect, &rectangles, list) {
if (contains(rect, x, y))
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 UDN is drained.
*/
BUG_ON(&rect->list == &rectangles);
/*
* 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 hardwall violation %#lx"
" while teardown already in progress\n",
cpu, (long) __insn_mfspr(SPR_UDN_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 UDN
* 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 hardwall violation %#lx...\n",
cpu, (long) __insn_mfspr(SPR_UDN_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_list) {
BUG_ON(p->thread.hardwall != rect);
if (p->sighand) {
found_processes = 1;
pr_notice("hardwall: killing %d\n", p->pid);
spin_lock(&p->sighand->siglock);
__group_send_sig_info(info.si_signo, &info, p);
spin_unlock(&p->sighand->siglock);
}
}
if (!found_processes)
pr_notice("hardwall: no associated processes!\n");
done:
spin_unlock_irqrestore(&hardwall_lock, flags);
/*
* 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();
irq_exit();
set_irq_regs(old_regs);
}
/* Allow access from user space to the UDN. */
void grant_network_mpls(void)
{
__insn_mtspr(SPR_MPL_UDN_ACCESS_SET_0, 1);
__insn_mtspr(SPR_MPL_UDN_AVAIL_SET_0, 1);
__insn_mtspr(SPR_MPL_UDN_COMPLETE_SET_0, 1);
__insn_mtspr(SPR_MPL_UDN_TIMER_SET_0, 1);
#if !CHIP_HAS_REV1_XDN()
__insn_mtspr(SPR_MPL_UDN_REFILL_SET_0, 1);
__insn_mtspr(SPR_MPL_UDN_CA_SET_0, 1);
#endif
}
/* Deny access from user space to the UDN. */
void restrict_network_mpls(void)
{
__insn_mtspr(SPR_MPL_UDN_ACCESS_SET_1, 1);
__insn_mtspr(SPR_MPL_UDN_AVAIL_SET_1, 1);
__insn_mtspr(SPR_MPL_UDN_COMPLETE_SET_1, 1);
__insn_mtspr(SPR_MPL_UDN_TIMER_SET_1, 1);
#if !CHIP_HAS_REV1_XDN()
__insn_mtspr(SPR_MPL_UDN_REFILL_SET_1, 1);
__insn_mtspr(SPR_MPL_UDN_CA_SET_1, 1);
#endif
}
/*
* Code to create, activate, deactivate, and destroy hardwall rectangles.
*/
/* Create a hardwall for the given rectangle */
static struct hardwall_info *hardwall_create(
size_t size, const unsigned char __user *bits)
{
struct hardwall_info *iter, *rect;
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 rectangle optimistically. */
rect = kmalloc(sizeof(struct hardwall_info),
GFP_KERNEL | __GFP_ZERO);
if (rect == NULL)
return ERR_PTR(-ENOMEM);
INIT_LIST_HEAD(&rect->task_head);
/* Compute the rectangle size and validate that it's plausible. */
rc = setup_rectangle(rect, &mask);
if (rc != 0) {
kfree(rect);
return ERR_PTR(rc);
}
/* Confirm it doesn't overlap and add it to the list. */
spin_lock_irqsave(&hardwall_lock, flags);
list_for_each_entry(iter, &rectangles, list) {
if (overlaps(iter, rect)) {
spin_unlock_irqrestore(&hardwall_lock, flags);
kfree(rect);
return ERR_PTR(-EBUSY);
}
}
list_add_tail(&rect->list, &rectangles);
spin_unlock_irqrestore(&hardwall_lock, flags);
/* Set up appropriate hardwalling on all affected cpus. */
hardwall_setup(rect);
return rect;
}
/* Activate a given hardwall on this cpu for this process. */
static int hardwall_activate(struct hardwall_info *rect)
{
int cpu, x, y;
unsigned long flags;
struct task_struct *p = current;
struct thread_struct *ts = &p->thread;
/* Require a rectangle. */
if (rect == NULL)
return -ENODATA;
/* Not allowed to activate a rectangle that is being torn down. */
if (rect->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 in this rectangle. */
cpu = smp_processor_id();
BUG_ON(cpumask_first(&p->cpus_allowed) != cpu);
x = cpu_x(cpu);
y = cpu_y(cpu);
if (!contains(rect, x, y))
return -EINVAL;
/* If we are already bound to this hardwall, it's a no-op. */
if (ts->hardwall) {
BUG_ON(ts->hardwall != rect);
return 0;
}
/* Success! This process gets to use the user networks on this cpu. */
ts->hardwall = rect;
spin_lock_irqsave(&hardwall_lock, flags);
list_add(&ts->hardwall_list, &rect->task_head);
spin_unlock_irqrestore(&hardwall_lock, flags);
grant_network_mpls();
printk(KERN_DEBUG "Pid %d (%s) activated for hardwall: cpu %d\n",
p->pid, p->comm, cpu);
return 0;
}
/*
* Deactivate a task's hardwall. Must hold hardwall_lock.
* This method may be called from free_task(), 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 task_struct *task)
{
struct thread_struct *ts = &task->thread;
if (cpumask_weight(&task->cpus_allowed) != 1) {
pr_err("pid %d (%s) releasing networks with"
" an affinity mask containing %d cpus!\n",
task->pid, task->comm,
cpumask_weight(&task->cpus_allowed));
BUG();
}
BUG_ON(ts->hardwall == NULL);
ts->hardwall = NULL;
list_del(&ts->hardwall_list);
if (task == current)
restrict_network_mpls();
}
/* Deactivate a task's hardwall. */
int hardwall_deactivate(struct task_struct *task)
{
unsigned long flags;
int activated;
spin_lock_irqsave(&hardwall_lock, flags);
activated = (task->thread.hardwall != NULL);
if (activated)
_hardwall_deactivate(task);
spin_unlock_irqrestore(&hardwall_lock, flags);
if (!activated)
return -EINVAL;
printk(KERN_DEBUG "Pid %d (%s) deactivated for hardwall: cpu %d\n",
task->pid, task->comm, smp_processor_id());
return 0;
}
/* Stop a UDN switch before draining the network. */
static void stop_udn_switch(void *ignored)
{
#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);
#endif
}
/* Drain all the state from a stopped switch. */
static void drain_udn_switch(void *ignored)
{
#if !CHIP_HAS_REV1_XDN()
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. */
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();
BUG_ON((__insn_mfspr(SPR_UDN_DATA_AVAIL) & 0xF) != 0);
/* 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 UDN state registers at boot up and during hardwall teardown. */
void reset_network_state(void)
{
#if !CHIP_HAS_REV1_XDN()
/* Reset UDN coordinates to their standard value */
unsigned int cpu = smp_processor_id();
unsigned int x = cpu % smp_width;
unsigned int y = cpu / smp_width;
#endif
if (udn_disabled)
return;
#if !CHIP_HAS_REV1_XDN()
__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));
#endif
/* Clear out other random registers so we have a clean slate. */
__insn_mtspr(SPR_UDN_AVAIL_EN, 0);
__insn_mtspr(SPR_UDN_DEADLOCK_TIMEOUT, 0);
#if !CHIP_HAS_REV1_XDN()
__insn_mtspr(SPR_UDN_REFILL_EN, 0);
__insn_mtspr(SPR_UDN_DEMUX_QUEUE_SEL, 0);
__insn_mtspr(SPR_UDN_SP_FIFO_SEL, 0);
#endif
/* Start the switch and demux. */
#if !CHIP_HAS_REV1_XDN()
__insn_mtspr(SPR_UDN_SP_FREEZE, 0);
#endif
}
/* Restart a UDN switch after draining. */
static void restart_udn_switch(void *ignored)
{
reset_network_state();
/* Disable firewall interrupts. */
__insn_mtspr(SPR_UDN_DIRECTION_PROTECT, 0);
disable_firewall_interrupts();
}
/* Build a struct cpumask containing all valid tiles in bounding rectangle. */
static void fill_mask(struct hardwall_info *r, struct cpumask *result)
{
int x, y, cpu;
cpumask_clear(result);
cpu = r->ulhc_y * smp_width + r->ulhc_x;
for (y = 0; y < r->height; ++y, cpu += smp_width - r->width) {
for (x = 0; x < r->width; ++x, ++cpu)
cpu_online_set(cpu, result);
}
}
/* Last reference to a hardwall is gone, so clear the network. */
static void hardwall_destroy(struct hardwall_info *rect)
{
struct task_struct *task;
unsigned long flags;
struct cpumask mask;
/* Make sure this file actually represents a rectangle. */
if (rect == 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.
*/
spin_lock_irqsave(&hardwall_lock, flags);
list_for_each_entry(task, &rect->task_head, thread.hardwall_list)
_hardwall_deactivate(task);
spin_unlock_irqrestore(&hardwall_lock, flags);
/* Drain the UDN. */
printk(KERN_DEBUG "Clearing hardwall rectangle %dx%d %d,%d\n",
rect->width, rect->height, rect->ulhc_x, rect->ulhc_y);
fill_mask(rect, &mask);
on_each_cpu_mask(&mask, stop_udn_switch, NULL, 1);
on_each_cpu_mask(&mask, drain_udn_switch, NULL, 1);
/* Restart switch and disable firewall. */
on_each_cpu_mask(&mask, restart_udn_switch, NULL, 1);
/* Now free the rectangle from the list. */
spin_lock_irqsave(&hardwall_lock, flags);
BUG_ON(!list_empty(&rect->task_head));
list_del(&rect->list);
spin_unlock_irqrestore(&hardwall_lock, flags);
kfree(rect);
}
/*
* Dump hardwall state via /proc; initialized in arch/tile/sys/proc.c.
*/
int proc_tile_hardwall_show(struct seq_file *sf, void *v)
{
struct hardwall_info *r;
if (udn_disabled) {
seq_printf(sf, "%dx%d 0,0 pids:\n", smp_width, smp_height);
return 0;
}
spin_lock_irq(&hardwall_lock);
list_for_each_entry(r, &rectangles, list) {
struct task_struct *p;
seq_printf(sf, "%dx%d %d,%d pids:",
r->width, r->height, r->ulhc_x, r->ulhc_y);
list_for_each_entry(p, &r->task_head, thread.hardwall_list) {
unsigned int cpu = cpumask_first(&p->cpus_allowed);
unsigned int x = cpu % smp_width;
unsigned int y = cpu / smp_width;
seq_printf(sf, " %d@%d,%d", p->pid, x, y);
}
seq_printf(sf, "\n");
}
spin_unlock_irq(&hardwall_lock);
return 0;
}
/*
* Character device support via ioctl/close.
*/
static long hardwall_ioctl(struct file *file, unsigned int a, unsigned long b)
{
struct hardwall_info *rect = file->private_data;
if (_IOC_TYPE(a) != HARDWALL_IOCTL_BASE)
return -EINVAL;
switch (_IOC_NR(a)) {
case _HARDWALL_CREATE:
if (udn_disabled)
return -ENOSYS;
if (rect != NULL)
return -EALREADY;
rect = hardwall_create(_IOC_SIZE(a),
(const unsigned char __user *)b);
if (IS_ERR(rect))
return PTR_ERR(rect);
file->private_data = rect;
return 0;
case _HARDWALL_ACTIVATE:
return hardwall_activate(rect);
case _HARDWALL_DEACTIVATE:
if (current->thread.hardwall != rect)
return -EINVAL;
return hardwall_deactivate(current);
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 *rect = file->private_data;
struct task_struct *task, *tmp;
unsigned long flags;
if (rect) {
/*
* NOTE: if multiple threads are activated on this hardwall
* file, the other threads will continue having access to the
* UDN 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.
*/
spin_lock_irqsave(&hardwall_lock, flags);
list_for_each_entry_safe(task, tmp, &rect->task_head,
thread.hardwall_list) {
if (task->files == owner || task->files == NULL)
_hardwall_deactivate(task);
}
spin_unlock_irqrestore(&hardwall_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, 1, "hardwall");
if (rc < 0)
return rc;
cdev_init(&hardwall_dev, &dev_hardwall_fops);
rc = cdev_add(&hardwall_dev, dev, 1);
if (rc < 0)
return rc;
return 0;
}
late_initcall(dev_hardwall_init);