kernel: 5.4: import wireguard backport

Rather than using the clunky, old, slower wireguard-linux-compat out of
tree module, this commit does a patch-by-patch backport of upstream's
wireguard to 5.4. This specific backport is in widespread use, being
part of SUSE's enterprise kernel, Oracle's enterprise kernel, Google's
Android kernel, Gentoo's distro kernel, and probably more I've forgotten
about. It's definately the "more proper" way of adding wireguard to a
kernel than the ugly compat.h hell of the wireguard-linux-compat repo.
And most importantly for OpenWRT, it allows using the same module
configuration code for 5.10 as for 5.4, with no need for bifurcation.

These patches are from the backport tree which is maintained in the
open here: https://git.zx2c4.com/wireguard-linux/log/?h=backport-5.4.y
I'll be sending PRs to update this as needed.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

1 files changed, 59 insertions, 0 deletions

diff --git a/target/linux/generic/backport-5.4/080-wireguard-0064-crypto-poly1305-x86_64-Use-XORL-r32-32.patch b/target/linux/generic/backport-5.4/080-wireguard-0064-crypto-poly1305-x86_64-Use-XORL-r32-32.patch
new file mode 100644
index 0000000000..fa5c1882da
--- /dev/null
+++ b/target/linux/generic/backport-5.4/080-wireguard-0064-crypto-poly1305-x86_64-Use-XORL-r32-32.patch
@@ -0,0 +1,59 @@
+From a2c7d387da3b3cdb8b7c16ef91cce45f92ebcf61 Mon Sep 17 00:00:00 2001
+From: Uros Bizjak <ubizjak@gmail.com>
+Date: Thu, 27 Aug 2020 19:38:31 +0200
+Subject: [PATCH 064/124] crypto: poly1305-x86_64 - Use XORL r32,32
+
+commit 7dfd1e01b3dfc13431b1b25720cf2692a7e111ef upstream.
+
+x86_64 zero extends 32bit operations, so for 64bit operands,
+XORL r32,r32 is functionally equal to XORQ r64,r64, but avoids
+a REX prefix byte when legacy registers are used.
+
+Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
+Cc: Herbert Xu <herbert@gondor.apana.org.au>
+Cc: "David S. Miller" <davem@davemloft.net>
+Acked-by: Jason A. Donenfeld <Jason@zx2c4.com>
+Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
+Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
+---
+ arch/x86/crypto/poly1305-x86_64-cryptogams.pl | 8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+--- a/arch/x86/crypto/poly1305-x86_64-cryptogams.pl
++++ b/arch/x86/crypto/poly1305-x86_64-cryptogams.pl
+@@ -246,7 +246,7 @@ $code.=<<___ if (!$kernel);
+ ___
+ &declare_function("poly1305_init_x86_64", 32, 3);
+ $code.=<<___;
+-	xor	%rax,%rax
++	xor	%eax,%eax
+ 	mov	%rax,0($ctx)		# initialize hash value
+ 	mov	%rax,8($ctx)
+ 	mov	%rax,16($ctx)
+@@ -2869,7 +2869,7 @@ $code.=<<___;
+ .type	poly1305_init_base2_44,\@function,3
+ .align	32
+ poly1305_init_base2_44:
+-	xor	%rax,%rax
++	xor	%eax,%eax
+ 	mov	%rax,0($ctx)		# initialize hash value
+ 	mov	%rax,8($ctx)
+ 	mov	%rax,16($ctx)
+@@ -3963,7 +3963,7 @@ xor128_decrypt_n_pad:
+ 	mov	\$16,$len
+ 	sub	%r10,$len
+ 	xor	%eax,%eax
+-	xor	%r11,%r11
++	xor	%r11d,%r11d
+ .Loop_dec_byte:
+ 	mov	($inp,$otp),%r11b
+ 	mov	($otp),%al
+@@ -4101,7 +4101,7 @@ avx_handler:
+ 	.long	0xa548f3fc		# cld; rep movsq
+ 
+ 	mov	$disp,%rsi
+-	xor	%rcx,%rcx		# arg1, UNW_FLAG_NHANDLER
++	xor	%ecx,%ecx		# arg1, UNW_FLAG_NHANDLER
+ 	mov	8(%rsi),%rdx		# arg2, disp->ImageBase
+ 	mov	0(%rsi),%r8		# arg3, disp->ControlPc
+ 	mov	16(%rsi),%r9		# arg4, disp->FunctionEntry