arch/arm64/mm/mem_encrypt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Implementation of the memory encryption/decryption API.
   4  *
   5  * Since the low-level details of the operation depend on the
   6  * Confidential Computing environment (e.g. pKVM, CCA, ...), this just
   7  * acts as a top-level dispatcher to whatever hooks may have been
   8  * registered.
   9  *
  10  * Author: Will Deacon <will@kernel.org>
  11  * Copyright (C) 2024 Google LLC
  12  *
  13  * "Hello, boils and ghouls!"
  14  */
  15
  16 #include <linux/bug.h>
  17 #include <linux/compiler.h>
  18 #include <linux/err.h>
  19 #include <linux/mm.h>
  20
  21 #include <asm/mem_encrypt.h>
  22
  23 static const struct arm64_mem_crypt_ops *crypt_ops;
  24
  25 int arm64_mem_crypt_ops_register(const struct arm64_mem_crypt_ops *ops)
  26 {
  27         if (WARN_ON(crypt_ops))
  28                 return -EBUSY;
  29
  30         crypt_ops = ops;
  31         return 0;
  32 }
  33
  34 int set_memory_encrypted(unsigned long addr, int numpages)
  35 {
  36         if (likely(!crypt_ops) || WARN_ON(!PAGE_ALIGNED(addr)))
  37                 return 0;
  38
  39         return crypt_ops->encrypt(addr, numpages);
  40 }
  41 EXPORT_SYMBOL_GPL(set_memory_encrypted);
  42
  43 int set_memory_decrypted(unsigned long addr, int numpages)
  44 {
  45         if (likely(!crypt_ops) || WARN_ON(!PAGE_ALIGNED(addr)))
  46                 return 0;
  47
  48         return crypt_ops->decrypt(addr, numpages);
  49 }
  50 EXPORT_SYMBOL_GPL(set_memory_decrypted);