crypto: arm/chacha - fix build failured when kernel mode NEON is disabled
When the ARM accelerated ChaCha driver is built as part of a configuration
that has kernel mode NEON disabled, we expect the compiler to propagate
the build time constant expression IS_ENABLED(CONFIG_KERNEL_MODE_NEON) in
a way that eliminates all the cross-object references to the actual NEON
routines, which allows the chacha-neon-core.o object to be omitted from
the build entirely.
Unfortunately, this fails to work as expected in some cases, and we may
end up with a build error such as
chacha-glue.c:(.text+0xc0): undefined reference to `chacha_4block_xor_neon'
caused by the fact that chacha_doneon() has not been eliminated from the
object code, even though it will never be called in practice.
Let's fix this by adding some IS_ENABLED(CONFIG_KERNEL_MODE_NEON) tests
that are not strictly needed from a logical point of view, but should
help the compiler infer that the NEON code paths are unreachable in
Fixes: b36d8c09e710c71f ("crypto: arm/chacha - remove dependency on generic ...")
Reported-by: Russell King <email@example.com>
Cc: Arnd Bergmann <firstname.lastname@example.org>
Signed-off-by: Ard Biesheuvel <email@example.com>
Signed-off-by: Herbert Xu <firstname.lastname@example.org>
1 file changed