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, 163 insertions, 0 deletions

diff --git a/target/linux/generic/backport-5.4/080-wireguard-0017-crypto-x86-poly1305-expose-existing-driver-as-poly13.patch b/target/linux/generic/backport-5.4/080-wireguard-0017-crypto-x86-poly1305-expose-existing-driver-as-poly13.patch
new file mode 100644
index 0000000000..01037a6ee6
--- /dev/null
+++ b/target/linux/generic/backport-5.4/080-wireguard-0017-crypto-x86-poly1305-expose-existing-driver-as-poly13.patch
@@ -0,0 +1,163 @@
+From 2ceb2e26de65cce974875e0487dde20bc5f1826c Mon Sep 17 00:00:00 2001
+From: Ard Biesheuvel <ardb@kernel.org>
+Date: Fri, 8 Nov 2019 13:22:23 +0100
+Subject: [PATCH 017/124] crypto: x86/poly1305 - expose existing driver as
+ poly1305 library
+
+commit f0e89bcfbb894e5844cd1bbf6b3cf7c63cb0f5ac upstream.
+
+Implement the arch init/update/final Poly1305 library routines in the
+accelerated SIMD driver for x86 so they are accessible to users of
+the Poly1305 library interface as well.
+
+Signed-off-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/poly1305_glue.c | 57 ++++++++++++++++++++++++---------
+ crypto/Kconfig                  |  1 +
+ lib/crypto/Kconfig              |  1 +
+ 3 files changed, 43 insertions(+), 16 deletions(-)
+
+--- a/arch/x86/crypto/poly1305_glue.c
++++ b/arch/x86/crypto/poly1305_glue.c
+@@ -10,6 +10,7 @@
+ #include <crypto/internal/poly1305.h>
+ #include <crypto/internal/simd.h>
+ #include <linux/crypto.h>
++#include <linux/jump_label.h>
+ #include <linux/kernel.h>
+ #include <linux/module.h>
+ #include <asm/simd.h>
+@@ -21,7 +22,8 @@ asmlinkage void poly1305_2block_sse2(u32
+ asmlinkage void poly1305_4block_avx2(u32 *h, const u8 *src, const u32 *r,
+ 				     unsigned int blocks, const u32 *u);
+ 
+-static bool poly1305_use_avx2 __ro_after_init;
++static __ro_after_init DEFINE_STATIC_KEY_FALSE(poly1305_use_simd);
++static __ro_after_init DEFINE_STATIC_KEY_FALSE(poly1305_use_avx2);
+ 
+ static void poly1305_simd_mult(u32 *a, const u32 *b)
+ {
+@@ -64,7 +66,7 @@ static unsigned int poly1305_simd_blocks
+ 	}
+ 
+ 	if (IS_ENABLED(CONFIG_AS_AVX2) &&
+-	    poly1305_use_avx2 &&
++	    static_branch_likely(&poly1305_use_avx2) &&
+ 	    srclen >= POLY1305_BLOCK_SIZE * 4) {
+ 		if (unlikely(dctx->rset < 4)) {
+ 			if (dctx->rset < 2) {
+@@ -103,10 +105,15 @@ static unsigned int poly1305_simd_blocks
+ 	return srclen;
+ }
+ 
+-static int poly1305_simd_update(struct shash_desc *desc,
+-				const u8 *src, unsigned int srclen)
++void poly1305_init_arch(struct poly1305_desc_ctx *desc, const u8 *key)
++{
++	poly1305_init_generic(desc, key);
++}
++EXPORT_SYMBOL(poly1305_init_arch);
++
++void poly1305_update_arch(struct poly1305_desc_ctx *dctx, const u8 *src,
++			  unsigned int srclen)
+ {
+-	struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
+ 	unsigned int bytes;
+ 
+ 	if (unlikely(dctx->buflen)) {
+@@ -117,7 +124,8 @@ static int poly1305_simd_update(struct s
+ 		dctx->buflen += bytes;
+ 
+ 		if (dctx->buflen == POLY1305_BLOCK_SIZE) {
+-			if (likely(crypto_simd_usable())) {
++			if (static_branch_likely(&poly1305_use_simd) &&
++			    likely(crypto_simd_usable())) {
+ 				kernel_fpu_begin();
+ 				poly1305_simd_blocks(dctx, dctx->buf,
+ 						     POLY1305_BLOCK_SIZE);
+@@ -131,7 +139,8 @@ static int poly1305_simd_update(struct s
+ 	}
+ 
+ 	if (likely(srclen >= POLY1305_BLOCK_SIZE)) {
+-		if (likely(crypto_simd_usable())) {
++		if (static_branch_likely(&poly1305_use_simd) &&
++		    likely(crypto_simd_usable())) {
+ 			kernel_fpu_begin();
+ 			bytes = poly1305_simd_blocks(dctx, src, srclen);
+ 			kernel_fpu_end();
+@@ -147,6 +156,13 @@ static int poly1305_simd_update(struct s
+ 		memcpy(dctx->buf, src, srclen);
+ 	}
+ }
++EXPORT_SYMBOL(poly1305_update_arch);
++
++void poly1305_final_arch(struct poly1305_desc_ctx *desc, u8 *digest)
++{
++	poly1305_final_generic(desc, digest);
++}
++EXPORT_SYMBOL(poly1305_final_arch);
+ 
+ static int crypto_poly1305_init(struct shash_desc *desc)
+ {
+@@ -171,6 +187,15 @@ static int crypto_poly1305_final(struct
+ 	return 0;
+ }
+ 
++static int poly1305_simd_update(struct shash_desc *desc,
++				const u8 *src, unsigned int srclen)
++{
++	struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
++
++	poly1305_update_arch(dctx, src, srclen);
++	return 0;
++}
++
+ static struct shash_alg alg = {
+ 	.digestsize	= POLY1305_DIGEST_SIZE,
+ 	.init		= crypto_poly1305_init,
+@@ -189,15 +214,15 @@ static struct shash_alg alg = {
+ static int __init poly1305_simd_mod_init(void)
+ {
+ 	if (!boot_cpu_has(X86_FEATURE_XMM2))
+-		return -ENODEV;
++		return 0;
+ 
+-	poly1305_use_avx2 = IS_ENABLED(CONFIG_AS_AVX2) &&
+-			    boot_cpu_has(X86_FEATURE_AVX) &&
+-			    boot_cpu_has(X86_FEATURE_AVX2) &&
+-			    cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL);
+-	alg.descsize = sizeof(struct poly1305_desc_ctx) + 5 * sizeof(u32);
+-	if (poly1305_use_avx2)
+-		alg.descsize += 10 * sizeof(u32);
++	static_branch_enable(&poly1305_use_simd);
++
++	if (IS_ENABLED(CONFIG_AS_AVX2) &&
++	    boot_cpu_has(X86_FEATURE_AVX) &&
++	    boot_cpu_has(X86_FEATURE_AVX2) &&
++	    cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL))
++		static_branch_enable(&poly1305_use_avx2);
+ 
+ 	return crypto_register_shash(&alg);
+ }
+--- a/crypto/Kconfig
++++ b/crypto/Kconfig
+@@ -698,6 +698,7 @@ config CRYPTO_POLY1305_X86_64
+ 	tristate "Poly1305 authenticator algorithm (x86_64/SSE2/AVX2)"
+ 	depends on X86 && 64BIT
+ 	select CRYPTO_LIB_POLY1305_GENERIC
++	select CRYPTO_ARCH_HAVE_LIB_POLY1305
+ 	help
+ 	  Poly1305 authenticator algorithm, RFC7539.
+ 
+--- a/lib/crypto/Kconfig
++++ b/lib/crypto/Kconfig
+@@ -39,6 +39,7 @@ config CRYPTO_LIB_DES
+ 
+ config CRYPTO_LIB_POLY1305_RSIZE
+ 	int
++	default 4 if X86_64
+ 	default 1
+ 
+ config CRYPTO_ARCH_HAVE_LIB_POLY1305