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, 37 insertions, 0 deletions

diff --git a/target/linux/generic/backport-5.4/080-wireguard-0070-crypto-lib-chacha20poly1305-define-empty-module-exit.patch b/target/linux/generic/backport-5.4/080-wireguard-0070-crypto-lib-chacha20poly1305-define-empty-module-exit.patch
new file mode 100644
index 0000000000..e4ca8892ca
--- /dev/null
+++ b/target/linux/generic/backport-5.4/080-wireguard-0070-crypto-lib-chacha20poly1305-define-empty-module-exit.patch
@@ -0,0 +1,37 @@
+From 06c613a67ec604201f424e8e763f3361264d995e Mon Sep 17 00:00:00 2001
+From: "Jason A. Donenfeld" <Jason@zx2c4.com>
+Date: Fri, 15 Jan 2021 20:30:12 +0100
+Subject: [PATCH 070/124] crypto: lib/chacha20poly1305 - define empty module
+ exit function
+
+commit ac88c322d0f2917d41d13553c69e9d7f043c8b6f upstream.
+
+With no mod_exit function, users are unable to unload the module after
+use. I'm not aware of any reason why module unloading should be
+prohibited for this one, so this commit simply adds an empty exit
+function.
+
+Reported-and-tested-by: John Donnelly <john.p.donnelly@oracle.com>
+Acked-by: Ard Biesheuvel <ardb@kernel.org>
+Signed-off-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>
+---
+ lib/crypto/chacha20poly1305.c | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+--- a/lib/crypto/chacha20poly1305.c
++++ b/lib/crypto/chacha20poly1305.c
+@@ -364,7 +364,12 @@ static int __init mod_init(void)
+ 	return 0;
+ }
+ 
++static void __exit mod_exit(void)
++{
++}
++
+ module_init(mod_init);
++module_exit(mod_exit);
+ MODULE_LICENSE("GPL v2");
+ MODULE_DESCRIPTION("ChaCha20Poly1305 AEAD construction");
+ MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>");