litmus-rt.git - The LITMUS^RT kernel.

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author	Namhoon Kim <namhoonk@cs.unc.edu>	2016-09-09 16:18:12 -0400
committer	Namhoon Kim <namhoonk@cs.unc.edu>	2016-09-09 16:18:12 -0400
commit	805c547ee3cdc2ef6a5f7556fdf449ced2e48680 (patch)
tree	abeae409739a576291942281f9acf56725d73a1a /arch/avr32/include/asm/tlb.h
parent	418e60bb6948a4cf6eb7c737bea21c2314619c73 (diff)

TODO: Fix condition checks in replicate_page_move_mapping()wip-shared-lib

Diffstat (limited to 'arch/avr32/include/asm/tlb.h')

0 files changed, 0 insertions, 0 deletions

// SPDX-License-Identifier: GPL-2.0-only /* * Pid namespaces * * Authors: * (C) 2007 Pavel Emelyanov <xemul@openvz.org>, OpenVZ, SWsoft Inc. * (C) 2007 Sukadev Bhattiprolu <sukadev@us.ibm.com>, IBM * Many thanks to Oleg Nesterov for comments and help * */ #include <linux/pid.h> #include <linux/pid_namespace.h> #include <linux/user_namespace.h> #include <linux/syscalls.h> #include <linux/cred.h> #include <linux/err.h> #include <linux/acct.h> #include <linux/slab.h> #include <linux/proc_ns.h> #include <linux/reboot.h> #include <linux/export.h> #include <linux/sched/task.h> #include <linux/sched/signal.h> #include <linux/idr.h> static DEFINE_MUTEX(pid_caches_mutex); static struct kmem_cache *pid_ns_cachep; /* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */ #define MAX_PID_NS_LEVEL 32 /* Write once array, filled from the beginning. */ static struct kmem_cache *pid_cache[MAX_PID_NS_LEVEL]; /* * creates the kmem cache to allocate pids from. * @level: pid namespace level */ static struct kmem_cache *create_pid_cachep(unsigned int level) { /* Level 0 is init_pid_ns.pid_cachep */ struct kmem_cache **pkc = &pid_cache[level - 1]; struct kmem_cache *kc; char name[4 + 10 + 1]; unsigned int len; kc = READ_ONCE(*pkc); if (kc) return kc; snprintf(name, sizeof(name), "pid_%u", level + 1); len = sizeof(struct pid) + level * sizeof(struct upid); mutex_lock(&pid_caches_mutex); /* Name collision forces to do allocation under mutex. */ if (!*pkc) *pkc = kmem_cache_create(name, len, 0, SLAB_HWCACHE_ALIGN, 0); mutex_unlock(&pid_caches_mutex); /* current can fail, but someone else can succeed. */ return READ_ONCE(*pkc); } static void proc_cleanup_work(struct work_struct *work) { struct pid_namespace *ns = container_of(work, struct pid_namespace, proc_work); pid_ns_release_proc(ns); } static struct ucounts *inc_pid_namespaces(struct user_namespace *ns) { return inc_ucount(ns, current_euid(), UCOUNT_PID_NAMESPACES); } static void dec_pid_namespaces(struct ucounts *ucounts) { dec_ucount(ucounts, UCOUNT_PID_NAMESPACES); } static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns, struct pid_namespace *parent_pid_ns) { struct pid_namespace *ns; unsigned int level = parent_pid_ns->level + 1; struct ucounts *ucounts; int err; err = -EINVAL; if (!in_userns(parent_pid_ns->user_ns, user_ns)) goto out; err = -ENOSPC; if (level > MAX_PID_NS_LEVEL) goto out; ucounts = inc_pid_namespaces(user_ns); if (!ucounts) goto out; err = -ENOMEM; ns = kmem_cache_zalloc(pid_ns_cachep, GFP_KERNEL); if (ns == NULL) goto out_dec; idr_init(&ns->idr); ns->pid_cachep = create_pid_cachep(level); if (ns->pid_cachep == NULL) goto out_free_idr; err = ns_alloc_inum(&ns->ns); if (err) goto out_free_idr; ns->ns.ops = &pidns_operations; kref_init(&ns->kref); ns->level = level; ns->parent = get_pid_ns(parent_pid_ns); ns->user_ns = get_user_ns(user_ns); ns->ucounts = ucounts; ns->pid_allocated = PIDNS_ADDING; INIT_WORK(&ns->proc_work, proc_cleanup_work); return ns; out_free_idr: idr_destroy(&ns->idr); kmem_cache_free(pid_ns_cachep, ns); out_dec: dec_pid_namespaces(ucounts); out: return ERR_PTR(err); } static void delayed_free_pidns(struct rcu_head *p) { struct pid_namespace *ns = container_of(p, struct pid_namespace, rcu); dec_pid_namespaces(ns->ucounts); put_user_ns(ns->user_ns); kmem_cache_free(pid_ns_cachep, ns); } static void destroy_pid_namespace(struct pid_namespace *ns) { ns_free_inum(&ns->ns); idr_destroy(&ns->idr); call_rcu(&ns->rcu, delayed_free_pidns); } struct pid_namespace *copy_pid_ns(unsigned long flags, struct user_namespace *user_ns, struct pid_namespace *old_ns) { if (!(flags & CLONE_NEWPID)) return get_pid_ns(old_ns); if (task_active_pid_ns(current) != old_ns) return ERR_PTR(-EINVAL); return create_pid_namespace(user_ns, old_ns); } static void free_pid_ns(struct kref *kref) { struct pid_namespace *ns; ns = container_of(kref, struct pid_namespace, kref); destroy_pid_namespace(ns); } void put_pid_ns(struct pid_namespace *ns) { struct pid_namespace *parent; while (ns != &init_pid_ns) { parent = ns->parent; if (!kref_put(&ns->kref, free_pid_ns)) break; ns = parent; } } EXPORT_SYMBOL_GPL(put_pid_ns); void zap_pid_ns_processes(struct pid_namespace *pid_ns) { int nr; int rc; struct task_struct *task, *me = current; int init_pids = thread_group_leader(me) ? 1 : 2; struct pid *pid; /* Don't allow any more processes into the pid namespace */ disable_pid_allocation(pid_ns); /* * Ignore SIGCHLD causing any terminated children to autoreap. * This speeds up the namespace shutdown, plus see the comment * below. */ spin_lock_irq(&me->sighand->siglock); me->sighand->action[SIGCHLD - 1].sa.sa_handler = SIG_IGN; spin_unlock_irq(&me->sighand->siglock); /* * The last thread in the cgroup-init thread group is terminating. * Find remaining pid_ts in the namespace, signal and wait for them * to exit. * * Note: This signals each threads in the namespace - even those that * belong to the same thread group, To avoid this, we would have * to walk the entire tasklist looking a processes in this * namespace, but that could be unnecessarily expensive if the * pid namespace has just a few processes. Or we need to * maintain a tasklist for each pid namespace. * */ rcu_read_lock(); read_lock(&tasklist_lock); nr = 2; idr_for_each_entry_continue(&pid_ns->idr, pid, nr) { task = pid_task(pid, PIDTYPE_PID); if (task && !__fatal_signal_pending(task)) group_send_sig_info(SIGKILL, SEND_SIG_PRIV, task, PIDTYPE_MAX); } read_unlock(&tasklist_lock); rcu_read_unlock(); /* * Reap the EXIT_ZOMBIE children we had before we ignored SIGCHLD. * kernel_wait4() will also block until our children traced from the * parent namespace are detached and become EXIT_DEAD. */ do { clear_thread_flag(TIF_SIGPENDING); rc = kernel_wait4(-1, NULL, __WALL, NULL); } while (rc != -ECHILD); /* * kernel_wait4() above can't reap the EXIT_DEAD children but we do not * really care, we could reparent them to the global init. We could * exit and reap ->child_reaper even if it is not the last thread in * this pid_ns, free_pid(pid_allocated == 0) calls proc_cleanup_work(), * pid_ns can not go away until proc_kill_sb() drops the reference. * * But this ns can also have other tasks injected by setns()+fork(). * Again, ignoring the user visible semantics we do not really need * to wait until they are all reaped, but they can be reparented to * us and thus we need to ensure that pid->child_reaper stays valid * until they all go away. See free_pid()->wake_up_process(). * * We rely on ignored SIGCHLD, an injected zombie must be autoreaped * if reparented. */ for (;;) { set_current_state(TASK_INTERRUPTIBLE); if (pid_ns->pid_allocated == init_pids) break; schedule(); } __set_current_state(TASK_RUNNING); if (pid_ns->reboot) current->signal->group_exit_code = pid_ns->reboot; acct_exit_ns(pid_ns); return; } #ifdef CONFIG_CHECKPOINT_RESTORE static int pid_ns_ctl_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { struct pid_namespace *pid_ns = task_active_pid_ns(current); struct ctl_table tmp = *table; int ret, next; if (write && !ns_capable(pid_ns->user_ns, CAP_SYS_ADMIN)) return -EPERM; /* * Writing directly to ns' last_pid field is OK, since this field * is volatile in a living namespace anyway and a code writing to * it should synchronize its usage with external means. */ next = idr_get_cursor(&pid_ns->idr) - 1; tmp.data = &next; ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos); if (!ret && write) idr_set_cursor(&pid_ns->idr, next + 1); return ret; } extern int pid_max; static struct ctl_table pid_ns_ctl_table[] = { { .procname = "ns_last_pid", .maxlen = sizeof(int), .mode = 0666, /* permissions are checked in the handler */ .proc_handler = pid_ns_ctl_handler, .extra1 = SYSCTL_ZERO, .extra2 = &pid_max, }, { } }; static struct ctl_path kern_path[] = { { .procname = "kernel", }, { } }; #endif /* CONFIG_CHECKPOINT_RESTORE */ int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd) { if (pid_ns == &init_pid_ns) return 0; switch (cmd) { case LINUX_REBOOT_CMD_RESTART2: case LINUX_REBOOT_CMD_RESTART: pid_ns->reboot = SIGHUP; break; case LINUX_REBOOT_CMD_POWER_OFF: case LINUX_REBOOT_CMD_HALT: pid_ns->reboot = SIGINT; break; default: return -EINVAL; } read_lock(&tasklist_lock); send_sig(SIGKILL, pid_ns->child_reaper, 1); read_unlock(&tasklist_lock); do_exit(0); /* Not reached */ return 0; } static inline struct pid_namespace *to_pid_ns(struct ns_common *ns) { return container_of(ns, struct pid_namespace, ns); } static struct ns_common *pidns_get(struct task_struct *task) { struct pid_namespace *ns; rcu_read_lock(); ns = task_active_pid_ns(task); if (ns) get_pid_ns(ns); rcu_read_unlock(); return ns ? &ns->ns : NULL; } static struct ns_common *pidns_for_children_get(struct task_struct *task) { struct pid_namespace *ns = NULL; task_lock(task); if (task->nsproxy) { ns = task->nsproxy->pid_ns_for_children; get_pid_ns(ns); } task_unlock(task); if (ns) { read_lock(&tasklist_lock); if (!ns->child_reaper) { put_pid_ns(ns); ns = NULL; } read_unlock(&tasklist_lock); } return ns ? &ns->ns : NULL; } static void pidns_put(struct ns_common *ns) { put_pid_ns(to_pid_ns(ns)); }


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