security/keys: add CONFIG_KEYS_COMPAT to Kconfig

CONFIG_KEYS_COMPAT is defined in arch-specific Kconfigs and is missing for
several 64-bit architectures : mips, parisc, tile.

At the moment and for those architectures, calling in 32-bit userspace the
keyctl syscall would return an ENOSYS error.

This patch moves the CONFIG_KEYS_COMPAT option to security/keys/Kconfig, to
make sure the compatibility wrapper is registered by default for any 64-bit
architecture as long as it is configured with CONFIG_COMPAT.

[DH: Modified to remove arm64 compat enablement also as requested by Eric
 Biggers]

Signed-off-by: Bilal Amarni <[email protected]>
Signed-off-by: David Howells <[email protected]>
Reviewed-by: Arnd Bergmann <[email protected]>
cc: Eric Biggers <[email protected]>
Signed-off-by: James Morris <[email protected]>
Link: https://patchwork.kernel.org/patch/9565609/
(cherry picked from commit 47b2c3f)
Tested-by: Seunghun Han <[email protected]>

Author: bamarni

arch/powerpc/Kconfig

@@ -1096,11 +1096,6 @@ source "arch/powerpc/Kconfig.debug"
 
 source "security/Kconfig"
 
-config KEYS_COMPAT
-	bool
-	depends on COMPAT && KEYS
-	default y
-
 source "crypto/Kconfig"
 
 config PPC_LIB_RHEAP

arch/s390/Kconfig

@@ -350,9 +350,6 @@ config COMPAT
 config SYSVIPC_COMPAT
 	def_bool y if COMPAT && SYSVIPC
 
-config KEYS_COMPAT
-	def_bool y if COMPAT && KEYS
-
 config SMP
 	def_bool y
 	prompt "Symmetric multi-processing support"

arch/sparc/Kconfig

@@ -544,9 +544,6 @@ config SYSVIPC_COMPAT
 	depends on COMPAT && SYSVIPC
 	default y
 
-config KEYS_COMPAT
-	def_bool y if COMPAT && KEYS
-
 endmenu
 
 source "net/Kconfig"

arch/x86/Kconfig

@@ -2701,10 +2701,6 @@ config COMPAT_FOR_U64_ALIGNMENT
 config SYSVIPC_COMPAT
 	def_bool y
 	depends on SYSVIPC
-
-config KEYS_COMPAT
-	def_bool y
-	depends on KEYS
 endif
 
 endmenu

security/keys/Kconfig

@@ -20,6 +20,10 @@ config KEYS
 
 	  If you are unsure as to whether this is required, answer N.
 
+config KEYS_COMPAT
+	def_bool y
+	depends on COMPAT && KEYS
+
 config PERSISTENT_KEYRINGS
 	bool "Enable register of persistent per-UID keyrings"
 	depends on KEYS