diff options
Diffstat (limited to 'arch/tile/kernel/hardwall.c')
| -rw-r--r-- | arch/tile/kernel/hardwall.c | 794 |
1 files changed, 794 insertions, 0 deletions
diff --git a/arch/tile/kernel/hardwall.c b/arch/tile/kernel/hardwall.c new file mode 100644 index 00000000000..7bf0627b733 --- /dev/null +++ b/arch/tile/kernel/hardwall.c @@ -0,0 +1,794 @@ +/* + * 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) +{ + raw_local_irq_unmask_now(INT_UDN_FIREWALL); +} + +static void disable_firewall_interrupts(void) +{ + raw_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); + 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 = { + .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); |