target/linux/generic/backport-5.4/080-wireguard-0064-crypto-poly1305-x86_64-Use-XORL-r32-32.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Uros Bizjak <ubizjak@gmail.com>
   3 Date: Thu, 27 Aug 2020 19:38:31 +0200
   4 Subject: [PATCH] crypto: poly1305-x86_64 - Use XORL r32,32
   5
   6 commit 7dfd1e01b3dfc13431b1b25720cf2692a7e111ef upstream.
   7
   8 x86_64 zero extends 32bit operations, so for 64bit operands,
   9 XORL r32,r32 is functionally equal to XORQ r64,r64, but avoids
  10 a REX prefix byte when legacy registers are used.
  11
  12 Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
  13 Cc: Herbert Xu <herbert@gondor.apana.org.au>
  14 Cc: "David S. Miller" <davem@davemloft.net>
  15 Acked-by: Jason A. Donenfeld <Jason@zx2c4.com>
  16 Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
  17 Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
  18 ---
  19  arch/x86/crypto/poly1305-x86_64-cryptogams.pl | 8 ++++----
  20  1 file changed, 4 insertions(+), 4 deletions(-)
  21
  22 --- a/arch/x86/crypto/poly1305-x86_64-cryptogams.pl
  23 +++ b/arch/x86/crypto/poly1305-x86_64-cryptogams.pl
  24 @@ -246,7 +246,7 @@ $code.=<<___ if (!$kernel);
  25  ___
  26  &declare_function("poly1305_init_x86_64", 32, 3);
  27  $code.=<<___;
  28 -       xor     %rax,%rax
  29 +       xor     %eax,%eax
  30         mov     %rax,0($ctx)            # initialize hash value
  31         mov     %rax,8($ctx)
  32         mov     %rax,16($ctx)
  33 @@ -2869,7 +2869,7 @@ $code.=<<___;
  34  .type  poly1305_init_base2_44,\@function,3
  35  .align 32
  36  poly1305_init_base2_44:
  37 -       xor     %rax,%rax
  38 +       xor     %eax,%eax
  39         mov     %rax,0($ctx)            # initialize hash value
  40         mov     %rax,8($ctx)
  41         mov     %rax,16($ctx)
  42 @@ -3963,7 +3963,7 @@ xor128_decrypt_n_pad:
  43         mov     \$16,$len
  44         sub     %r10,$len
  45         xor     %eax,%eax
  46 -       xor     %r11,%r11
  47 +       xor     %r11d,%r11d
  48  .Loop_dec_byte:
  49         mov     ($inp,$otp),%r11b
  50         mov     ($otp),%al
  51 @@ -4101,7 +4101,7 @@ avx_handler:
  52         .long   0xa548f3fc              # cld; rep movsq
  53
  54         mov     $disp,%rsi
  55 -       xor     %rcx,%rcx               # arg1, UNW_FLAG_NHANDLER
  56 +       xor     %ecx,%ecx               # arg1, UNW_FLAG_NHANDLER
  57         mov     8(%rsi),%rdx            # arg2, disp->ImageBase
  58         mov     0(%rsi),%r8             # arg3, disp->ControlPc
  59         mov     16(%rsi),%r9            # arg4, disp->FunctionEntry