126 lines
2.5 KiB
C
126 lines
2.5 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2015-2021, Linaro Limited
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/arm-smccc.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/tee_drv.h>
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#include "optee_private.h"
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struct notif_entry {
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struct list_head link;
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struct completion c;
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u_int key;
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};
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static bool have_key(struct optee *optee, u_int key)
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{
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struct notif_entry *entry;
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list_for_each_entry(entry, &optee->notif.db, link)
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if (entry->key == key)
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return true;
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return false;
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}
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int optee_notif_wait(struct optee *optee, u_int key)
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{
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unsigned long flags;
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struct notif_entry *entry;
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int rc = 0;
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if (key > optee->notif.max_key)
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return -EINVAL;
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entry = kmalloc(sizeof(*entry), GFP_KERNEL);
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if (!entry)
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return -ENOMEM;
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init_completion(&entry->c);
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entry->key = key;
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spin_lock_irqsave(&optee->notif.lock, flags);
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/*
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* If the bit is already set it means that the key has already
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* been posted and we must not wait.
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*/
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if (test_bit(key, optee->notif.bitmap)) {
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clear_bit(key, optee->notif.bitmap);
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goto out;
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}
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/*
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* Check if someone is already waiting for this key. If there is
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* it's a programming error.
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*/
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if (have_key(optee, key)) {
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rc = -EBUSY;
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goto out;
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}
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list_add_tail(&entry->link, &optee->notif.db);
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/*
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* Unlock temporarily and wait for completion.
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*/
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spin_unlock_irqrestore(&optee->notif.lock, flags);
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wait_for_completion(&entry->c);
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spin_lock_irqsave(&optee->notif.lock, flags);
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list_del(&entry->link);
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out:
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spin_unlock_irqrestore(&optee->notif.lock, flags);
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kfree(entry);
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return rc;
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}
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int optee_notif_send(struct optee *optee, u_int key)
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{
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unsigned long flags;
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struct notif_entry *entry;
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if (key > optee->notif.max_key)
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return -EINVAL;
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spin_lock_irqsave(&optee->notif.lock, flags);
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list_for_each_entry(entry, &optee->notif.db, link)
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if (entry->key == key) {
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complete(&entry->c);
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goto out;
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}
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/* Only set the bit in case there where nobody waiting */
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set_bit(key, optee->notif.bitmap);
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out:
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spin_unlock_irqrestore(&optee->notif.lock, flags);
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return 0;
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}
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int optee_notif_init(struct optee *optee, u_int max_key)
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{
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spin_lock_init(&optee->notif.lock);
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INIT_LIST_HEAD(&optee->notif.db);
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optee->notif.bitmap = bitmap_zalloc(max_key, GFP_KERNEL);
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if (!optee->notif.bitmap)
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return -ENOMEM;
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optee->notif.max_key = max_key;
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return 0;
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}
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void optee_notif_uninit(struct optee *optee)
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{
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bitmap_free(optee->notif.bitmap);
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}
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