Re: [dpdk-dev] [PATCH v3 2/2] build: add support for detecting march on ARM

[Bruce Richardson <bruce.richardson@intel.com>]

On Fri, Jan 19, 2018 at 07:22:51PM +0530, Pavan Nikhilesh wrote:
> Added support for detecting march and mcpu by reading midr_el1 register.
> The implementer, primary part number values read can be used to figure
> out the underlying arm cpu.
> 
> Signed-off-by: Pavan Nikhilesh <pbhagavatula@caviumnetworks.com>
> ---
>  app/test-pmd/meson.build    |  2 +-
>  config/arm/armv8_machine.py | 18 +++++++++++
>  config/arm/meson.build      | 76 ++++++++++++++++++++++++++++++++++++++++-----
>  config/meson.build          | 19 ++++++------
>  drivers/meson.build         |  2 +-
>  examples/meson.build        |  2 +-
>  lib/meson.build             |  2 +-
>  meson.build                 |  2 +-
>  test/test/meson.build       |  2 +-
>  9 files changed, 102 insertions(+), 23 deletions(-)
>  create mode 100755 config/arm/armv8_machine.py
> 
> diff --git a/app/test-pmd/meson.build b/app/test-pmd/meson.build
> index e819677a5..2a3f0ba1f 100644
> --- a/app/test-pmd/meson.build
> +++ b/app/test-pmd/meson.build
> @@ -45,7 +45,7 @@ endif
>  
>  executable('dpdk-testpmd',
>  	sources,
> -	c_args: machine_arg,
> +	c_args: machine_args,
>  	link_whole: link_libs,
>  	dependencies: dep_objs,
>  	install_rpath: join_paths(get_option('prefix'), driver_install_path),
> diff --git a/config/arm/armv8_machine.py b/config/arm/armv8_machine.py
> new file mode 100755
> index 000000000..404866d2f
> --- /dev/null
> +++ b/config/arm/armv8_machine.py
> @@ -0,0 +1,18 @@
> +#!/usr/bin/python
> +# SPDX-License-Identifier: BSD-3-Clause
> +# Copyright(c) 2017 Cavium, Inc
> +
> +ident = []
> +fname = '/sys/devices/system/cpu/cpu0/regs/identification/midr_el1'
> +with open(fname) as f:
> +    content = f.read()
> +
> +midr_el1 = (int(content.rstrip('\n'), 16))
> +
> +ident.append(hex((midr_el1 >> 24) & 0xFF))  # Implementer
> +ident.append(hex((midr_el1 >> 20) & 0xF))   # Variant
> +ident.append(hex((midr_el1 >> 16) & 0XF))   # Architecture
> +ident.append(hex((midr_el1 >> 4) & 0xFFF))  # Primary Part number
> +ident.append(hex(midr_el1 & 0xF))           # Revision
> +
> +print(' '.join(ident))
> diff --git a/config/arm/meson.build b/config/arm/meson.build
> index f05de4c2c..62af5e68a 100644
> --- a/config/arm/meson.build
> +++ b/config/arm/meson.build
> @@ -5,28 +5,88 @@
>  # for checking defines we need to use the correct compiler flags
>  march_opt = '-march=@0@'.format(machine)
>  
> +machine_args_cavium = [
> +	['default', ['-march=armv8-a+crc+crypto','-mcpu=thunderx']],
> +	['0xa1', ['-mcpu=thunderxt88']],
> +	['0xa2', ['-mcpu=thunderxt81']],
> +	['0xa3', ['-mcpu=thunderxt83']]]
> +
> +flags_cavium = [
> +	['RTE_MACHINE', '"thunderx"'],
> +	['RTE_CACHE_LINE_SIZE', 128],
> +	['RTE_MAX_NUMA_NODES', 2],
> +	['RTE_MAX_LCORE', 96],
> +	['RTE_MAX_VFIO_GROUPS', 128],
> +	['RTE_RING_USE_C11_MEM_MODEL', false]]
> +
> +impl_0x43 = ['Cavium', flags_cavium, machine_args_cavium]
> +
> +dpdk_conf.set('RTE_TOOLCHAIN', '"gcc"')

dpdk_conf.set_quoted() is probably what you want here.

> +dpdk_conf.set('RTE_TOOLCHAIN_GCC', 1)
<snip>
> dpdk_conf.set('RTE_MACHINE_CPUFLAG_SHA1', 1)
> diff --git a/config/meson.build b/config/meson.build
> index fa55c53a5..f8c67578d 100644
> --- a/config/meson.build
> +++ b/config/meson.build
> @@ -8,7 +8,8 @@ else
>  	machine = get_option('machine')
>  endif
>  dpdk_conf.set('RTE_MACHINE', machine)
> -machine_arg = '-march=' + machine
> +machine_args = []
> +machine_args += '-march=' + machine
>  
>  # use pthreads
>  add_project_link_arguments('-pthread', language: 'c')
> @@ -53,6 +54,14 @@ foreach arg: warning_flags
>  	endif
>  endforeach
>  
> +# set other values pulled from the build options
> +dpdk_conf.set('RTE_MAX_LCORE', get_option('max_lcores'))
> +dpdk_conf.set('RTE_MAX_NUMA_NODES', get_option('max_numa_nodes'))
> +dpdk_conf.set('RTE_LIBEAL_USE_HPET', get_option('use_hpet'))
> +dpdk_conf.set('RTE_EAL_ALLOW_INV_SOCKET_ID', get_option('allow_invalid_socket_id'))
> +# values which have defaults which may be overridden
> +dpdk_conf.set('RTE_MAX_VFIO_GROUPS', 64)
> +
>  compile_time_cpuflags = []
>  if host_machine.cpu_family().startswith('x86')
>  	arch_subdir = 'x86'
> @@ -65,12 +74,4 @@ dpdk_conf.set('RTE_COMPILE_TIME_CPUFLAGS', ','.join(compile_time_cpuflags))
>  # set the install path for the drivers
>  dpdk_conf.set_quoted('RTE_EAL_PMD_PATH', eal_pmd_path)
>  
> -# set other values pulled from the build options
> -dpdk_conf.set('RTE_MAX_LCORE', get_option('max_lcores'))
> -dpdk_conf.set('RTE_MAX_NUMA_NODES', get_option('max_numa_nodes'))
> -dpdk_conf.set('RTE_LIBEAL_USE_HPET', get_option('use_hpet'))
> -dpdk_conf.set('RTE_EAL_ALLOW_INV_SOCKET_ID', get_option('allow_invalid_socket_id'))
> -# values which have defaults which may be overridden
> -dpdk_conf.set('RTE_MAX_VFIO_GROUPS', 64)
> -
Is there a reason why these lines have been moved?