git.openwrt.org Git - openwrt/staging/stintel.git/blob

   1 From 6d99147c19566e0f82eccef876f5aae2bc8d1fcb Mon Sep 17 00:00:00 2001
   2 From: Ben Avison <bavison@riscosopen.org>
   3 Date: Mon, 8 Mar 2021 15:32:25 +0000
   4 Subject: [PATCH] Assign crypto aliases to different AES implementation
   5  modules
   6
   7 The kernel modules aes-neon-blk and aes-neon-bs perform poorly, at least on
   8 Cortex-A72 without crypto extensions. In fact, aes-arm64 outperforms them
   9 on benchmarks, despite it being a simpler implementation (only accelerating
  10 the single-block AES cipher).
  11
  12 For modes of operation where multiple cipher blocks can be processed in
  13 parallel, aes-neon-bs outperforms aes-neon-blk by around 60-70% and aes-arm64
  14 is another 10-20% faster still. But the difference is even more marked with
  15 modes of operation with dependencies between neighbouring blocks, such as
  16 CBC encryption, which defeat parallelism: in these cases, aes-arm64 is
  17 typically around 250% faster than either aes-neon-blk or aes-neon-bs.
  18
  19 The key trade-off with aes-arm64 is that the look-up tables are situated in
  20 RAM. This leaves them potentially open to cache timing attacks. The two other
  21 modules, by contrast, load the look-up tables into NEON registers and so are
  22 able to perform in constant time.
  23
  24 This patch aims to load aes-arm64 more often.
  25
  26 If none of the currently-loaded crypto modules implement a given algorithm,
  27 a new one is typically selected for loading using a platform-neutral alias
  28 describing the required algorithm. To enable users to still
  29 load aes-neon-blk or aes-neon-bs if they really want them, while still
  30 ensuring that aes-arm64 is usually selected, remove the aliases from
  31 aes-neonbs-glue.c and aes-glue.c and apply them to aes-cipher-glue.c, but
  32 still build the two NEON modules.
  33
  34 Since aes-glue.c can also be used to build aes-ce-blk, leave them enabled
  35 if USE_V8_CRYPTO_EXTENSIONS is defined, to ensure they are selected if we
  36 in future use a CPU which has the crypto extensions enabled.
  37
  38 Note that the algorithm priority specifiers are unchanged, so if
  39 aes-neon-bs is loaded at the same time as aes-arm64, the former will be
  40 used in preference. However, aes-neon-blk and aes-arm64 have tied priority,
  41 so whichever module was loaded first will be used (assuming aes-neon-bs is
  42 not loaded).
  43
  44 Signed-off-by: Ben Avison <bavison@riscosopen.org>
  45 ---
  46  arch/arm64/crypto/aes-cipher-glue.c | 10 ++++++++++
  47  arch/arm64/crypto/aes-glue.c        |  4 ++--
  48  arch/arm64/crypto/aes-neonbs-glue.c |  5 -----
  49  3 files changed, 12 insertions(+), 7 deletions(-)
  50
  51 --- a/arch/arm64/crypto/aes-cipher-glue.c
  52 +++ b/arch/arm64/crypto/aes-cipher-glue.c
  53 @@ -9,6 +9,16 @@
  54  #include <linux/crypto.h>
  55  #include <linux/module.h>
  56
  57 +MODULE_ALIAS_CRYPTO("ecb(aes)");
  58 +MODULE_ALIAS_CRYPTO("cbc(aes)");
  59 +MODULE_ALIAS_CRYPTO("ctr(aes)");
  60 +MODULE_ALIAS_CRYPTO("xts(aes)");
  61 +MODULE_ALIAS_CRYPTO("cts(cbc(aes))");
  62 +MODULE_ALIAS_CRYPTO("essiv(cbc(aes),sha256)");
  63 +MODULE_ALIAS_CRYPTO("cmac(aes)");
  64 +MODULE_ALIAS_CRYPTO("xcbc(aes)");
  65 +MODULE_ALIAS_CRYPTO("cbcmac(aes)");
  66 +
  67  asmlinkage void __aes_arm64_encrypt(u32 *rk, u8 *out, const u8 *in, int rounds);
  68  asmlinkage void __aes_arm64_decrypt(u32 *rk, u8 *out, const u8 *in, int rounds);
  69
  70 --- a/arch/arm64/crypto/aes-glue.c
  71 +++ b/arch/arm64/crypto/aes-glue.c
  72 @@ -55,17 +55,17 @@ MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS
  73  #define aes_mac_update         neon_aes_mac_update
  74  MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS using ARMv8 NEON");
  75  #endif
  76 -#if defined(USE_V8_CRYPTO_EXTENSIONS) || !IS_ENABLED(CONFIG_CRYPTO_AES_ARM64_BS)
  77 +#if defined(USE_V8_CRYPTO_EXTENSIONS)
  78  MODULE_ALIAS_CRYPTO("ecb(aes)");
  79  MODULE_ALIAS_CRYPTO("cbc(aes)");
  80  MODULE_ALIAS_CRYPTO("ctr(aes)");
  81  MODULE_ALIAS_CRYPTO("xts(aes)");
  82 -#endif
  83  MODULE_ALIAS_CRYPTO("cts(cbc(aes))");
  84  MODULE_ALIAS_CRYPTO("essiv(cbc(aes),sha256)");
  85  MODULE_ALIAS_CRYPTO("cmac(aes)");
  86  MODULE_ALIAS_CRYPTO("xcbc(aes)");
  87  MODULE_ALIAS_CRYPTO("cbcmac(aes)");
  88 +#endif
  89
  90  MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
  91  MODULE_LICENSE("GPL v2");
  92 --- a/arch/arm64/crypto/aes-neonbs-glue.c
  93 +++ b/arch/arm64/crypto/aes-neonbs-glue.c
  94 @@ -18,11 +18,6 @@
  95  MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
  96  MODULE_LICENSE("GPL v2");
  97
  98 -MODULE_ALIAS_CRYPTO("ecb(aes)");
  99 -MODULE_ALIAS_CRYPTO("cbc(aes)");
 100 -MODULE_ALIAS_CRYPTO("ctr(aes)");
 101 -MODULE_ALIAS_CRYPTO("xts(aes)");
 102 -
 103  asmlinkage void aesbs_convert_key(u8 out[], u32 const rk[], int rounds);
 104
 105  asmlinkage void aesbs_ecb_encrypt(u8 out[], u8 const in[], u8 const rk[],