Re: [dpdk-dev] [PATCH v2] build: disable armv8 crypto extension

[Dharmik Thakkar <Dharmik.Thakkar@arm.com>]

Hi Yongseok,
Thank you for the patch! I have tested it on Bluefield reference platform. It works fine. 

One observation:
Even though I used 'make config T=arm64-bluefield-linuxapp-gcc’,
at the end of the build process it said 'Build complete [arm64-armv8a-linuxapp-gcc]’

Tested-by: Dharmik Thakkar <dharmik.thakkar@arm.com>

> On May 3, 2019, at 7:28 AM, Yongseok Koh <yskoh@mellanox.com> wrote:
> 
> Per armv8 crypto extension support, make build always enable it by default
> as long as compiler supports the feature while meson build only enables it
> for 'default' machine of generic armv8 architecture.
> 
> It is known that not all the armv8 platforms have the crypto extension. For
> example, Mellanox BlueField has a variant which doesn't have it. If crypto
> enabled binary runs on such a platform, rte_eal_init() fails.
> 
> '+crypto' flag currently implies only '+aes' and '+sha2' and enabling it
> will generate the crypto instructions only when crypto intrinsics are used.
> For the devices supporting 8.2 crypto or newer, compiler could generate
> such instructions beyond intrinsics or asm code. For example, compiler can
> generate 3-way exclusive OR instructions if sha3 is supported. However, it
> has to be enabled by adding '+sha3' as of today.
> 
> In DPDK, armv8 cryptodev is the only one which requires the crypto support.
> As it even uses external library of Marvell which is compiled out of DPDK
> with crypto support and there's run-time check for required cpuflags,
> crypto support can be disabled in DPDK.
> 
> Cc: stable@dpdk.org
> 
> Signed-off-by: Yongseok Koh <yskoh@mellanox.com>
> ---
> 
> v2:
> * disable crypto support instead of having a build config
> 
> config/arm/meson.build        | 2 +-
> mk/machine/armv8a/rte.vars.mk | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/config/arm/meson.build b/config/arm/meson.build
> index 7fa6ed3105..abc8cf346c 100644
> --- a/config/arm/meson.build
> +++ b/config/arm/meson.build
> @@ -74,7 +74,7 @@ flags_octeontx2_extra = [
> 	['RTE_USE_C11_MEM_MODEL', true]]
> 
> machine_args_generic = [
> -	['default', ['-march=armv8-a+crc+crypto']],
> +	['default', ['-march=armv8-a+crc']],
> 	['native', ['-march=native']],
> 	['0xd03', ['-mcpu=cortex-a53']],
> 	['0xd04', ['-mcpu=cortex-a35']],
> diff --git a/mk/machine/armv8a/rte.vars.mk b/mk/machine/armv8a/rte.vars.mk
> index 8252efbb7b..5e3ffc3adf 100644
> --- a/mk/machine/armv8a/rte.vars.mk
> +++ b/mk/machine/armv8a/rte.vars.mk
> @@ -28,4 +28,4 @@
> # CPU_LDFLAGS =
> # CPU_ASFLAGS =
> 
> -MACHINE_CFLAGS += -march=armv8-a+crc+crypto
> +MACHINE_CFLAGS += -march=armv8-a+crc
> -- 
> 2.11.0
>