1 files changed, 75 insertions, 0 deletions
diff --git a/target/linux/generic/backport-5.4/080-wireguard-0028-crypto-lib-curve25519-work-around-Clang-stack-spilli.patch b/target/linux/generic/backport-5.4/080-wireguard-0028-crypto-lib-curve25519-work-around-Clang-stack-spilli.patch
new file mode 100644
index 0000000000..36b59c9aae
--- /dev/null
+++ b/target/linux/generic/backport-5.4/080-wireguard-0028-crypto-lib-curve25519-work-around-Clang-stack-spilli.patch
@@ -0,0 +1,75 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Ard Biesheuvel <ardb@kernel.org>
+Date: Fri, 8 Nov 2019 13:22:35 +0100
+Subject: [PATCH] crypto: lib/curve25519 - work around Clang stack spilling
+ issue
+
+commit 660bb8e1f833ea63185fe80fde847e3e42f18e3b upstream.
+
+Arnd reports that the 32-bit generic library code for Curve25119 ends
+up using an excessive amount of stack space when built with Clang:
+
+  lib/crypto/curve25519-fiat32.c:756:6: error: stack frame size
+      of 1384 bytes in function 'curve25519_generic'
+      [-Werror,-Wframe-larger-than=]
+
+Let's give some hints to the compiler regarding which routines should
+not be inlined, to prevent it from running out of registers and spilling
+to the stack. The resulting code performs identically under both GCC
+and Clang, and makes the warning go away.
+
+Suggested-by: Arnd Bergmann <arnd@arndb.de>
+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>
+---
+ lib/crypto/curve25519-fiat32.c | 10 +++++-----
+ 1 file changed, 5 insertions(+), 5 deletions(-)
+
+--- a/lib/crypto/curve25519-fiat32.c
++++ b/lib/crypto/curve25519-fiat32.c
+@@ -223,7 +223,7 @@ static __always_inline void fe_1(fe *h)
+ 	h->v[0] = 1;
+ }
+ 
+-static void fe_add_impl(u32 out[10], const u32 in1[10], const u32 in2[10])
++static noinline void fe_add_impl(u32 out[10], const u32 in1[10], const u32 in2[10])
+ {
+ 	{ const u32 x20 = in1[9];
+ 	{ const u32 x21 = in1[8];
+@@ -266,7 +266,7 @@ static __always_inline void fe_add(fe_lo
+ 	fe_add_impl(h->v, f->v, g->v);
+ }
+ 
+-static void fe_sub_impl(u32 out[10], const u32 in1[10], const u32 in2[10])
++static noinline void fe_sub_impl(u32 out[10], const u32 in1[10], const u32 in2[10])
+ {
+ 	{ const u32 x20 = in1[9];
+ 	{ const u32 x21 = in1[8];
+@@ -309,7 +309,7 @@ static __always_inline void fe_sub(fe_lo
+ 	fe_sub_impl(h->v, f->v, g->v);
+ }
+ 
+-static void fe_mul_impl(u32 out[10], const u32 in1[10], const u32 in2[10])
++static noinline void fe_mul_impl(u32 out[10], const u32 in1[10], const u32 in2[10])
+ {
+ 	{ const u32 x20 = in1[9];
+ 	{ const u32 x21 = in1[8];
+@@ -441,7 +441,7 @@ fe_mul_tll(fe *h, const fe_loose *f, con
+ 	fe_mul_impl(h->v, f->v, g->v);
+ }
+ 
+-static void fe_sqr_impl(u32 out[10], const u32 in1[10])
++static noinline void fe_sqr_impl(u32 out[10], const u32 in1[10])
+ {
+ 	{ const u32 x17 = in1[9];
+ 	{ const u32 x18 = in1[8];
+@@ -619,7 +619,7 @@ static __always_inline void fe_invert(fe
+  *
+  * Preconditions: b in {0,1}
+  */
+-static __always_inline void fe_cswap(fe *f, fe *g, unsigned int b)
++static noinline void fe_cswap(fe *f, fe *g, unsigned int b)
+ {
+ 	unsigned i;
+ 	b = 0 - b;