127 lines
3.2 KiB
C
127 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/types.h>
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#include <linux/module.h>
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#include <linux/crc64.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <crypto/hash.h>
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#include <crypto/algapi.h>
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#include <linux/static_key.h>
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#include <linux/notifier.h>
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static struct crypto_shash __rcu *crc64_rocksoft_tfm;
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static DEFINE_STATIC_KEY_TRUE(crc64_rocksoft_fallback);
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static DEFINE_MUTEX(crc64_rocksoft_mutex);
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static struct work_struct crc64_rocksoft_rehash_work;
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static int crc64_rocksoft_notify(struct notifier_block *self, unsigned long val, void *data)
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{
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struct crypto_alg *alg = data;
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if (val != CRYPTO_MSG_ALG_LOADED ||
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strcmp(alg->cra_name, CRC64_ROCKSOFT_STRING))
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return NOTIFY_DONE;
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schedule_work(&crc64_rocksoft_rehash_work);
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return NOTIFY_OK;
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}
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static void crc64_rocksoft_rehash(struct work_struct *work)
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{
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struct crypto_shash *new, *old;
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mutex_lock(&crc64_rocksoft_mutex);
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old = rcu_dereference_protected(crc64_rocksoft_tfm,
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lockdep_is_held(&crc64_rocksoft_mutex));
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new = crypto_alloc_shash(CRC64_ROCKSOFT_STRING, 0, 0);
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if (IS_ERR(new)) {
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mutex_unlock(&crc64_rocksoft_mutex);
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return;
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}
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rcu_assign_pointer(crc64_rocksoft_tfm, new);
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mutex_unlock(&crc64_rocksoft_mutex);
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if (old) {
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synchronize_rcu();
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crypto_free_shash(old);
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} else {
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static_branch_disable(&crc64_rocksoft_fallback);
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}
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}
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static struct notifier_block crc64_rocksoft_nb = {
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.notifier_call = crc64_rocksoft_notify,
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};
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u64 crc64_rocksoft_update(u64 crc, const unsigned char *buffer, size_t len)
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{
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struct {
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struct shash_desc shash;
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u64 crc;
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} desc;
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int err;
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if (static_branch_unlikely(&crc64_rocksoft_fallback))
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return crc64_rocksoft_generic(crc, buffer, len);
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rcu_read_lock();
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desc.shash.tfm = rcu_dereference(crc64_rocksoft_tfm);
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desc.crc = crc;
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err = crypto_shash_update(&desc.shash, buffer, len);
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rcu_read_unlock();
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BUG_ON(err);
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return desc.crc;
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}
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EXPORT_SYMBOL_GPL(crc64_rocksoft_update);
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u64 crc64_rocksoft(const unsigned char *buffer, size_t len)
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{
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return crc64_rocksoft_update(0, buffer, len);
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}
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EXPORT_SYMBOL_GPL(crc64_rocksoft);
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static int __init crc64_rocksoft_mod_init(void)
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{
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INIT_WORK(&crc64_rocksoft_rehash_work, crc64_rocksoft_rehash);
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crypto_register_notifier(&crc64_rocksoft_nb);
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crc64_rocksoft_rehash(&crc64_rocksoft_rehash_work);
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return 0;
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}
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static void __exit crc64_rocksoft_mod_fini(void)
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{
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crypto_unregister_notifier(&crc64_rocksoft_nb);
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cancel_work_sync(&crc64_rocksoft_rehash_work);
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crypto_free_shash(rcu_dereference_protected(crc64_rocksoft_tfm, 1));
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}
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module_init(crc64_rocksoft_mod_init);
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module_exit(crc64_rocksoft_mod_fini);
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static int crc64_rocksoft_transform_show(char *buffer, const struct kernel_param *kp)
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{
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struct crypto_shash *tfm;
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int len;
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if (static_branch_unlikely(&crc64_rocksoft_fallback))
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return sprintf(buffer, "fallback\n");
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rcu_read_lock();
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tfm = rcu_dereference(crc64_rocksoft_tfm);
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len = snprintf(buffer, PAGE_SIZE, "%s\n",
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crypto_shash_driver_name(tfm));
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rcu_read_unlock();
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return len;
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}
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module_param_call(transform, NULL, crc64_rocksoft_transform_show, NULL, 0444);
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MODULE_AUTHOR("Keith Busch <kbusch@kernel.org>");
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MODULE_DESCRIPTION("Rocksoft model CRC64 calculation (library API)");
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MODULE_LICENSE("GPL");
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MODULE_SOFTDEP("pre: crc64");
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