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, 32 insertions, 0 deletions

diff --git a/target/linux/generic/backport-5.4/080-wireguard-0035-crypto-x86-chacha-only-unregister-algorithms-if-regi.patch b/target/linux/generic/backport-5.4/080-wireguard-0035-crypto-x86-chacha-only-unregister-algorithms-if-regi.patch
new file mode 100644
index 0000000000..f423acb90b
--- /dev/null
+++ b/target/linux/generic/backport-5.4/080-wireguard-0035-crypto-x86-chacha-only-unregister-algorithms-if-regi.patch
@@ -0,0 +1,32 @@
+From 4fa6b436d97e44deef404676d150ed4c13d63bba Mon Sep 17 00:00:00 2001
+From: Eric Biggers <ebiggers@google.com>
+Date: Sun, 17 Nov 2019 23:21:58 -0800
+Subject: [PATCH 035/124] crypto: x86/chacha - only unregister algorithms if
+ registered
+
+commit b62755aed3a3f5ca9edd2718339ccea3b6bbbe57 upstream.
+
+It's not valid to call crypto_unregister_skciphers() without a prior
+call to crypto_register_skciphers().
+
+Fixes: 84e03fa39fbe ("crypto: x86/chacha - expose SIMD ChaCha routine as library function")
+Signed-off-by: Eric Biggers <ebiggers@google.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/x86/crypto/chacha_glue.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+--- a/arch/x86/crypto/chacha_glue.c
++++ b/arch/x86/crypto/chacha_glue.c
+@@ -304,7 +304,8 @@ static int __init chacha_simd_mod_init(v
+ 
+ static void __exit chacha_simd_mod_fini(void)
+ {
+-	crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
++	if (boot_cpu_has(X86_FEATURE_SSSE3))
++		crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
+ }
+ 
+ module_init(chacha_simd_mod_init);