[PATCH] crypto: lib/Kconfig - fix chacha/poly1305 dependencies more more

[Arnd Bergmann <arnd@kernel.org>]

From: Arnd Bergmann <arnd@arndb.de>

A recent change tries to fix Kconfig dependencies, but introduced
two problems in the process:

 - only arm, powerpc and x86 are changed, while mips, arm64 and s390
   are now broken

 - there are now configurations where the architecture enables its
   own helper functions as loadable modules, but they remain silently
   unused because CRYPTO_LIB_* falls back to the generic helpers

Address both by changing the logic again: the architecture functions
select CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA, which may be a loadable
module or built-in, and this controls whether the library is
also built-in.

Fixes: 04f9ccc955c7 ("crypto: lib/Kconfig - Fix lib built-in failure when arch is modular")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
I did not quite understand what problem the 04f9ccc955c7 patch
actually tried to solve, so there is a chance that my version
undoes it. I tested this on randconfig builds across, arm,
arm64 and x86 and found no other dependency problems with these
libraries.
---
 arch/arm64/crypto/Kconfig |  4 ++--
 arch/mips/crypto/Kconfig  |  4 ++--
 arch/s390/crypto/Kconfig  |  2 +-
 lib/crypto/Kconfig        | 20 +++++++++++---------
 4 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/crypto/Kconfig b/arch/arm64/crypto/Kconfig
index 5636ab83f22a..3d90efdcf5a5 100644
--- a/arch/arm64/crypto/Kconfig
+++ b/arch/arm64/crypto/Kconfig
@@ -29,7 +29,7 @@ config CRYPTO_POLY1305_NEON
 	tristate "Hash functions: Poly1305 (NEON)"
 	depends on KERNEL_MODE_NEON
 	select CRYPTO_HASH
-	select CRYPTO_ARCH_HAVE_LIB_POLY1305
+	select CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305
 	help
 	  Poly1305 authenticator algorithm (RFC7539)
 
@@ -190,7 +190,7 @@ config CRYPTO_CHACHA20_NEON
 	depends on KERNEL_MODE_NEON
 	select CRYPTO_SKCIPHER
 	select CRYPTO_LIB_CHACHA_GENERIC
-	select CRYPTO_ARCH_HAVE_LIB_CHACHA
+	select CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA
 	help
 	  Length-preserving ciphers: ChaCha20, XChaCha20, and XChaCha12
 	  stream cipher algorithms
diff --git a/arch/mips/crypto/Kconfig b/arch/mips/crypto/Kconfig
index 7decd40c4e20..cbeb2f62eb79 100644
--- a/arch/mips/crypto/Kconfig
+++ b/arch/mips/crypto/Kconfig
@@ -5,7 +5,7 @@ menu "Accelerated Cryptographic Algorithms for CPU (mips)"
 config CRYPTO_POLY1305_MIPS
 	tristate "Hash functions: Poly1305"
 	depends on MIPS
-	select CRYPTO_ARCH_HAVE_LIB_POLY1305
+	select CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305
 	help
 	  Poly1305 authenticator algorithm (RFC7539)
 
@@ -55,7 +55,7 @@ config CRYPTO_CHACHA_MIPS
 	tristate "Ciphers: ChaCha20, XChaCha20, XChaCha12 (MIPS32r2)"
 	depends on CPU_MIPS32_R2
 	select CRYPTO_SKCIPHER
-	select CRYPTO_ARCH_HAVE_LIB_CHACHA
+	select CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA
 	help
 	  Length-preserving ciphers: ChaCha20, XChaCha20, and XChaCha12
 	  stream cipher algorithms
diff --git a/arch/s390/crypto/Kconfig b/arch/s390/crypto/Kconfig
index b760232537f1..6f7495264943 100644
--- a/arch/s390/crypto/Kconfig
+++ b/arch/s390/crypto/Kconfig
@@ -112,7 +112,7 @@ config CRYPTO_CHACHA_S390
 	depends on S390
 	select CRYPTO_SKCIPHER
 	select CRYPTO_LIB_CHACHA_GENERIC
-	select CRYPTO_ARCH_HAVE_LIB_CHACHA
+	select CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA
 	help
 	  Length-preserving cipher: ChaCha20 stream cipher (RFC 7539)
 
diff --git a/lib/crypto/Kconfig b/lib/crypto/Kconfig
index c542ef1d64d0..6b45bd634cd9 100644
--- a/lib/crypto/Kconfig
+++ b/lib/crypto/Kconfig
@@ -50,8 +50,6 @@ config CRYPTO_ARCH_HAVE_LIB_CHACHA
 
 config CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA
 	tristate
-	select CRYPTO_ARCH_HAVE_LIB_CHACHA if CRYPTO_LIB_CHACHA=m
-	select CRYPTO_ARCH_HAVE_LIB_CHACHA if CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA=y
 
 config CRYPTO_LIB_CHACHA_GENERIC
 	tristate
@@ -65,7 +63,9 @@ config CRYPTO_LIB_CHACHA_GENERIC
 
 config CRYPTO_LIB_CHACHA
 	tristate "ChaCha library interface"
-	select CRYPTO_LIB_CHACHA_GENERIC if CRYPTO_ARCH_HAVE_LIB_CHACHA=n
+	select CRYPTO_LIB_CHACHA_GENERIC if CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA=n
+	select CRYPTO_ARCH_HAVE_LIB_CHACHA if CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA!=n
+	depends on CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA || !CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA
 	help
 	  Enable the ChaCha library interface. This interface may be fulfilled
 	  by either the generic implementation or an arch-specific one, if one
@@ -80,8 +80,6 @@ config CRYPTO_ARCH_HAVE_LIB_CURVE25519
 
 config CRYPTO_ARCH_MAY_HAVE_LIB_CURVE25519
 	tristate
-	select CRYPTO_ARCH_HAVE_LIB_CURVE25519 if CRYPTO_LIB_CURVE25519=m
-	select CRYPTO_ARCH_HAVE_LIB_CURVE25519 if CRYPTO_ARCH_MAY_HAVE_LIB_CURVE25519=y
 
 config CRYPTO_LIB_CURVE25519_GENERIC
 	tristate
@@ -94,7 +92,9 @@ config CRYPTO_LIB_CURVE25519_GENERIC
 
 config CRYPTO_LIB_CURVE25519
 	tristate "Curve25519 scalar multiplication library"
-	select CRYPTO_LIB_CURVE25519_GENERIC if CRYPTO_ARCH_HAVE_LIB_CURVE25519=n
+	select CRYPTO_LIB_CURVE25519_GENERIC if CRYPTO_ARCH_MAY_HAVE_LIB_CURVE25519=n
+	select CRYPTO_ARCH_HAVE_LIB_CURVE25519 if CRYPTO_ARCH_MAY_HAVE_LIB_CURVE25519!=n
+	depends on CRYPTO_ARCH_MAY_HAVE_LIB_CURVE25519 || !CRYPTO_ARCH_MAY_HAVE_LIB_CURVE25519
 	select CRYPTO_LIB_UTILS
 	help
 	  Enable the Curve25519 library interface. This interface may be
@@ -120,8 +120,6 @@ config CRYPTO_ARCH_HAVE_LIB_POLY1305
 
 config CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305
 	tristate
-	select CRYPTO_ARCH_HAVE_LIB_POLY1305 if CRYPTO_LIB_POLY1305=m
-	select CRYPTO_ARCH_HAVE_LIB_POLY1305 if CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305=y
 
 config CRYPTO_LIB_POLY1305_GENERIC
 	tristate
@@ -134,7 +132,9 @@ config CRYPTO_LIB_POLY1305_GENERIC
 
 config CRYPTO_LIB_POLY1305
 	tristate "Poly1305 library interface"
-	select CRYPTO_LIB_POLY1305_GENERIC if CRYPTO_ARCH_HAVE_LIB_POLY1305=n
+	select CRYPTO_LIB_POLY1305_GENERIC if CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305=n
+	select CRYPTO_ARCH_HAVE_LIB_POLY1305 if CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305!=n
+	depends on CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305 || !CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305
 	help
 	  Enable the Poly1305 library interface. This interface may be fulfilled
 	  by either the generic implementation or an arch-specific one, if one
@@ -143,6 +143,8 @@ config CRYPTO_LIB_POLY1305
 config CRYPTO_LIB_CHACHA20POLY1305
 	tristate "ChaCha20-Poly1305 AEAD support (8-byte nonce library version)"
 	depends on CRYPTO
+	depends on CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305 || !CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305
+	depends on CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA || !CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA
 	select CRYPTO_LIB_CHACHA
 	select CRYPTO_LIB_POLY1305
 	select CRYPTO_ALGAPI
-- 
2.39.5