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, 38 insertions, 0 deletions

diff --git a/target/linux/generic/backport-5.4/080-wireguard-0039-crypto-arm-curve25519-add-arch-specific-key-generati.patch b/target/linux/generic/backport-5.4/080-wireguard-0039-crypto-arm-curve25519-add-arch-specific-key-generati.patch
new file mode 100644
index 0000000000..19d1338594
--- /dev/null
+++ b/target/linux/generic/backport-5.4/080-wireguard-0039-crypto-arm-curve25519-add-arch-specific-key-generati.patch
@@ -0,0 +1,38 @@
+From 610442255536492764547dddde0289d46a9566db Mon Sep 17 00:00:00 2001
+From: "Jason A. Donenfeld" <Jason@zx2c4.com>
+Date: Wed, 11 Dec 2019 10:26:39 +0100
+Subject: [PATCH 039/124] crypto: arm/curve25519 - add arch-specific key
+ generation function
+
+commit 84faa307249b341f6ad8de3e1869d77a65e26669 upstream.
+
+Somehow this was forgotten when Zinc was being split into oddly shaped
+pieces, resulting in linker errors. The x86_64 glue has a specific key
+generation implementation, but the Arm one does not. However, it can
+still receive the NEON speedups by calling the ordinary DH function
+using the base point.
+
+Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
+Acked-by: Ard Biesheuvel <ardb@kernel.org>
+Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
+Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
+---
+ arch/arm/crypto/curve25519-glue.c | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+--- a/arch/arm/crypto/curve25519-glue.c
++++ b/arch/arm/crypto/curve25519-glue.c
+@@ -38,6 +38,13 @@ void curve25519_arch(u8 out[CURVE25519_K
+ }
+ EXPORT_SYMBOL(curve25519_arch);
+ 
++void curve25519_base_arch(u8 pub[CURVE25519_KEY_SIZE],
++			  const u8 secret[CURVE25519_KEY_SIZE])
++{
++	return curve25519_arch(pub, secret, curve25519_base_point);
++}
++EXPORT_SYMBOL(curve25519_base_arch);
++
+ static int curve25519_set_secret(struct crypto_kpp *tfm, const void *buf,
+ 				 unsigned int len)
+ {