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, 84 insertions, 0 deletions

diff --git a/target/linux/generic/backport-5.4/080-wireguard-0052-crypto-x86-curve25519-support-assemblers-with-no-adx.patch b/target/linux/generic/backport-5.4/080-wireguard-0052-crypto-x86-curve25519-support-assemblers-with-no-adx.patch
new file mode 100644
index 0000000000..9a380d377c
--- /dev/null
+++ b/target/linux/generic/backport-5.4/080-wireguard-0052-crypto-x86-curve25519-support-assemblers-with-no-adx.patch
@@ -0,0 +1,84 @@
+From 50af997532492b0f55bd9928743ac1f99dc1cd41 Mon Sep 17 00:00:00 2001
+From: "Jason A. Donenfeld" <Jason@zx2c4.com>
+Date: Sun, 1 Mar 2020 22:52:35 +0800
+Subject: [PATCH 052/124] crypto: x86/curve25519 - support assemblers with no
+ adx support
+
+commit 1579f1bc3b753d17a44de3457d5c6f4a5b14c752 upstream.
+
+Some older version of GAS do not support the ADX instructions, similarly
+to how they also don't support AVX and such. This commit adds the same
+build-time detection mechanisms we use for AVX and others for ADX, and
+then makes sure that the curve25519 library dispatcher calls the right
+functions.
+
+Reported-by: Willy Tarreau <w@1wt.eu>
+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>
+---
+ arch/x86/Makefile           | 5 +++--
+ arch/x86/crypto/Makefile    | 7 ++++++-
+ include/crypto/curve25519.h | 6 ++++--
+ 3 files changed, 13 insertions(+), 5 deletions(-)
+
+--- a/arch/x86/Makefile
++++ b/arch/x86/Makefile
+@@ -197,9 +197,10 @@ avx2_instr :=$(call as-instr,vpbroadcast
+ avx512_instr :=$(call as-instr,vpmovm2b %k1$(comma)%zmm5,-DCONFIG_AS_AVX512=1)
+ sha1_ni_instr :=$(call as-instr,sha1msg1 %xmm0$(comma)%xmm1,-DCONFIG_AS_SHA1_NI=1)
+ sha256_ni_instr :=$(call as-instr,sha256msg1 %xmm0$(comma)%xmm1,-DCONFIG_AS_SHA256_NI=1)
++adx_instr := $(call as-instr,adox %r10$(comma)%r10,-DCONFIG_AS_ADX=1)
+ 
+-KBUILD_AFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr)
+-KBUILD_CFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr)
++KBUILD_AFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr) $(adx_instr)
++KBUILD_CFLAGS += $(cfi) $(cfi-sigframe) $(cfi-sections) $(asinstr) $(avx_instr) $(avx2_instr) $(avx512_instr) $(sha1_ni_instr) $(sha256_ni_instr) $(adx_instr)
+ 
+ KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
+ 
+--- a/arch/x86/crypto/Makefile
++++ b/arch/x86/crypto/Makefile
+@@ -11,6 +11,7 @@ avx2_supported := $(call as-instr,vpgath
+ avx512_supported :=$(call as-instr,vpmovm2b %k1$(comma)%zmm5,yes,no)
+ sha1_ni_supported :=$(call as-instr,sha1msg1 %xmm0$(comma)%xmm1,yes,no)
+ sha256_ni_supported :=$(call as-instr,sha256msg1 %xmm0$(comma)%xmm1,yes,no)
++adx_supported := $(call as-instr,adox %r10$(comma)%r10,yes,no)
+ 
+ obj-$(CONFIG_CRYPTO_GLUE_HELPER_X86) += glue_helper.o
+ 
+@@ -39,7 +40,11 @@ obj-$(CONFIG_CRYPTO_AEGIS128_AESNI_SSE2)
+ 
+ obj-$(CONFIG_CRYPTO_NHPOLY1305_SSE2) += nhpoly1305-sse2.o
+ obj-$(CONFIG_CRYPTO_NHPOLY1305_AVX2) += nhpoly1305-avx2.o
+-obj-$(CONFIG_CRYPTO_CURVE25519_X86) += curve25519-x86_64.o
++
++# These modules require the assembler to support ADX.
++ifeq ($(adx_supported),yes)
++	obj-$(CONFIG_CRYPTO_CURVE25519_X86) += curve25519-x86_64.o
++endif
+ 
+ # These modules require assembler to support AVX.
+ ifeq ($(avx_supported),yes)
+--- a/include/crypto/curve25519.h
++++ b/include/crypto/curve25519.h
+@@ -33,7 +33,8 @@ bool __must_check curve25519(u8 mypublic
+ 			     const u8 secret[CURVE25519_KEY_SIZE],
+ 			     const u8 basepoint[CURVE25519_KEY_SIZE])
+ {
+-	if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CURVE25519))
++	if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CURVE25519) &&
++	    (!IS_ENABLED(CONFIG_CRYPTO_CURVE25519_X86) || IS_ENABLED(CONFIG_AS_ADX)))
+ 		curve25519_arch(mypublic, secret, basepoint);
+ 	else
+ 		curve25519_generic(mypublic, secret, basepoint);
+@@ -49,7 +50,8 @@ __must_check curve25519_generate_public(
+ 				    CURVE25519_KEY_SIZE)))
+ 		return false;
+ 
+-	if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CURVE25519))
++	if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CURVE25519) &&
++	    (!IS_ENABLED(CONFIG_CRYPTO_CURVE25519_X86) || IS_ENABLED(CONFIG_AS_ADX)))
+ 		curve25519_base_arch(pub, secret);
+ 	else
+ 		curve25519_generic(pub, secret, curve25519_base_point);