| From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 |
| From: Ard Biesheuvel <ardb@kernel.org> |
| Date: Fri, 17 Jan 2020 17:43:18 +0100 |
| Subject: [PATCH] crypto: arm/chacha - fix build failured when kernel mode NEON |
| is disabled |
| |
| commit 0bc81767c5bd9d005fae1099fb39eb3688370cb1 upstream. |
| |
| 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 |
| those cases. |
| |
| Fixes: b36d8c09e710c71f ("crypto: arm/chacha - remove dependency on generic ...") |
| Reported-by: Russell King <linux@armlinux.org.uk> |
| Cc: 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> |
| --- |
| arch/arm/crypto/chacha-glue.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/arch/arm/crypto/chacha-glue.c |
| +++ b/arch/arm/crypto/chacha-glue.c |
| @@ -115,7 +115,7 @@ static int chacha_stream_xor(struct skci |
| if (nbytes < walk.total) |
| nbytes = round_down(nbytes, walk.stride); |
| |
| - if (!neon) { |
| + if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !neon) { |
| chacha_doarm(walk.dst.virt.addr, walk.src.virt.addr, |
| nbytes, state, ctx->nrounds); |
| state[12] += DIV_ROUND_UP(nbytes, CHACHA_BLOCK_SIZE); |
| @@ -159,7 +159,7 @@ static int do_xchacha(struct skcipher_re |
| |
| chacha_init_generic(state, ctx->key, req->iv); |
| |
| - if (!neon) { |
| + if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !neon) { |
| hchacha_block_arm(state, subctx.key, ctx->nrounds); |
| } else { |
| kernel_neon_begin(); |