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kernel/user-return-notifier.c
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// SPDX-License-Identifier: GPL-2.0-only |
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#include <linux/user-return-notifier.h> #include <linux/percpu.h> #include <linux/sched.h> |
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#include <linux/export.h> |
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static DEFINE_PER_CPU(struct hlist_head, return_notifier_list); |
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/* * Request a notification when the current cpu returns to userspace. Must be * called in atomic context. The notifier will also be called in atomic * context. */ void user_return_notifier_register(struct user_return_notifier *urn) { set_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY); |
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hlist_add_head(&urn->link, this_cpu_ptr(&return_notifier_list)); |
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} EXPORT_SYMBOL_GPL(user_return_notifier_register); /* * Removes a registered user return notifier. Must be called from atomic |
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* context, and from the same cpu registration occurred in. |
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*/ void user_return_notifier_unregister(struct user_return_notifier *urn) { hlist_del(&urn->link); |
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if (hlist_empty(this_cpu_ptr(&return_notifier_list))) |
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clear_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY); } EXPORT_SYMBOL_GPL(user_return_notifier_unregister); /* Calls registered user return notifiers */ void fire_user_return_notifiers(void) { struct user_return_notifier *urn; |
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struct hlist_node *tmp2; |
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struct hlist_head *head; head = &get_cpu_var(return_notifier_list); |
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hlist_for_each_entry_safe(urn, tmp2, head, link) |
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urn->on_user_return(urn); |
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put_cpu_var(return_notifier_list); |
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} |