Re: [dpdk-dev] [PATCH v6] build: kni cross-compilation support

["Juraj Linkeš" <juraj.linkes@pantheon.tech>]

Hi Folks,

Does anyone have any comments? Is the patch ready? If so, please send acks or reviewed-by, thanks.

Andrew, did you get a chance to test the patch?

Juraj

> -----Original Message-----
> From: Juraj Linkeš <juraj.linkes@pantheon.tech>
> Sent: Thursday, February 11, 2021 2:00 PM
> To: bruce.richardson@intel.com; thomas@monjalon.net;
> Ruifeng.Wang@arm.com; Honnappa.Nagarahalli@arm.com;
> jerinjacobk@gmail.com; hemant.agrawal@nxp.com; ferruh.yigit@intel.com;
> aboyer@pensando.io
> Cc: dev@dpdk.org; Juraj Linkeš <juraj.linkes@pantheon.tech>
> Subject: [PATCH v6] build: kni cross-compilation support
> 
> The kni linux module is using a custom target for building, which doesn't take
> into account any cross compilation arguments. The arguments in question are
> ARCH, CROSS_COMPILE (for gcc, clang) and CC, LD (for clang). Get those from
> the cross file and pass them to the custom target.
> 
> The user supplied path may not contain the 'build' directory, such as when using
> cross-compiled headers, so only append that in the default case (when no path is
> supplied in native builds) and use the unmodified path from the user otherwise.
> Also modify the install path accordingly.
> 
> Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>
> Reviewed-by: Bruce Richardson <bruce.richardson@intel.com>
> ---
>  kernel/linux/kni/meson.build |  8 ++--
>  kernel/linux/meson.build     | 90 ++++++++++++++++++++++++++++++------
>  meson_options.txt            |  2 +-
>  3 files changed, 82 insertions(+), 18 deletions(-)
> 
> diff --git a/kernel/linux/kni/meson.build b/kernel/linux/kni/meson.build index
> 07e0c9dae7..46b71c7418 100644
> --- a/kernel/linux/kni/meson.build
> +++ b/kernel/linux/kni/meson.build
> @@ -13,7 +13,7 @@ kni_sources = files(
>  custom_target('rte_kni',
>  	input: kni_sources,
>  	output: 'rte_kni.ko',
> -	command: ['make', '-j4', '-C', kernel_dir + '/build',
> +	command: ['make', '-j4', '-C', kernel_build_dir,
>  		'M=' + meson.current_build_dir(),
>  		'src=' + meson.current_source_dir(),
>  		'MODULE_CFLAGS=-include ' + meson.source_root() +
> '/config/rte_config.h' + @@ -21,8 +21,8 @@ custom_target('rte_kni',
>  		' -I' + meson.source_root() + '/lib/librte_kni' +
>  		' -I' + meson.build_root() +
>  		' -I' + meson.current_source_dir(),
> -		'modules'],
> +		'modules'] + cross_args,
>  	depends: kni_mkfile,
> -	install: true,
> -	install_dir: kernel_dir + '/extra/dpdk',
> +	install: install,
> +	install_dir: kernel_install_dir,
>  	build_by_default: get_option('enable_kmods')) diff --git
> a/kernel/linux/meson.build b/kernel/linux/meson.build index
> 5c864a4653..7b15e0fd44 100644
> --- a/kernel/linux/meson.build
> +++ b/kernel/linux/meson.build
> @@ -3,25 +3,89 @@
> 
>  subdirs = ['kni']
> 
> -# if we are cross-compiling we need kernel_dir specified -if
> get_option('kernel_dir') == '' and meson.is_cross_build()
> -	error('Need "kernel_dir" option for kmod compilation when cross-
> compiling')
> -endif
> +kernel_build_dir = get_option('kernel_dir') kernel_install_dir = ''
> +install = not meson.is_cross_build()
> +cross_args = []
> 
> -kernel_dir = get_option('kernel_dir')
> -if kernel_dir == ''
> -	# use default path for native builds
> +if not meson.is_cross_build()
> +	# native build
>  	kernel_version = run_command('uname', '-r').stdout().strip()
> -	kernel_dir = '/lib/modules/' + kernel_version
> +	kernel_install_dir = '/lib/modules/' + kernel_version + '/extra/dpdk'
> +	if kernel_build_dir == ''
> +		# use default path for native builds
> +		kernel_build_dir = '/lib/modules/' + kernel_version + '/build'
> +	endif
> +
> +	# test running make in kernel directory, using "make kernelversion"
> +	make_returncode = run_command('make', '-sC', kernel_build_dir,
> +			'kernelversion').returncode()
> +	if make_returncode != 0
> +		# backwards compatibility:
> +		# the headers could still be in the 'build' subdir
> +		if not kernel_build_dir.endswith('build') and not
> kernel_build_dir.endswith('build/')
> +			kernel_build_dir = join_paths(kernel_build_dir, 'build')
> +			make_returncode = run_command('make', '-sC',
> kernel_build_dir,
> +					'kernelversion').returncode()
> +		endif
> +	endif
> +
> +	if make_returncode != 0
> +		error('Cannot compile kernel modules as requested - are kernel
> headers installed?')
> +	endif
> +
> +	# DO ACTUAL MODULE BUILDING
> +	foreach d:subdirs
> +		subdir(d)
> +	endforeach
> +
> +	subdir_done()
>  endif
> 
> -# test running make in kernel directory, using "make kernelversion"
> -make_returncode = run_command('make', '-sC', kernel_dir + '/build',
> -		'kernelversion').returncode()
> -if make_returncode != 0
> -	error('Cannot compile kernel modules as requested - are kernel headers
> installed?')
> +# cross build
> +# if we are cross-compiling we need kernel_build_dir specified if
> +kernel_build_dir == ''
> +	error('Need "kernel_dir" option for kmod compilation when
> +cross-compiling') endif cross_compiler = find_program('c').path() if
> +cross_compiler.endswith('gcc')
> +	cross_prefix = run_command([py3, '-c', 'print("' + cross_compiler +
> +'"[:-3])']).stdout().strip() elif cross_compiler.endswith('clang')
> +	cross_prefix = ''
> +	found_target = false
> +	# search for '-target' and use the arg that follows
> +	# (i.e. the value of '-target') as cross_prefix
> +	foreach cross_c_arg : meson.get_cross_property('c_args')
> +		if found_target and cross_prefix == ''
> +			cross_prefix = cross_c_arg
> +		endif
> +		if cross_c_arg == '-target'
> +			found_target = true
> +		endif
> +	endforeach
> +	if cross_prefix == ''
> +		error('Didn\'t find -target and its value in' +
> +		      ' c_args in input cross-file.')
> +	endif
> +	linker = 'lld'
> +	foreach cross_c_link_arg : meson.get_cross_property('c_link_args')
> +		if cross_c_link_arg.startswith('-fuse-ld')
> +			linker = cross_c_link_arg.split('=')[1]
> +		endif
> +	endforeach
> +	cross_args += ['CC=@0@'.format(cross_compiler),
> +'LD=ld.@0@'.format(linker)] else
> +	error('Unsupported cross compiler: @0@'.format(cross_compiler))
>  endif
> 
> +cross_arch = host_machine.cpu_family()
> +if host_machine.cpu_family() == 'aarch64'
> +	cross_arch = 'arm64'
> +endif
> +
> +cross_args += ['ARCH=@0@'.format(cross_arch),
> +	'CROSS_COMPILE=@0@'.format(cross_prefix)]
> +
>  # DO ACTUAL MODULE BUILDING
>  foreach d:subdirs
>  	subdir(d)
> diff --git a/meson_options.txt b/meson_options.txt index
> 6eff62e47d..3b8c5d316d 100644
> --- a/meson_options.txt
> +++ b/meson_options.txt
> @@ -19,7 +19,7 @@ option('ibverbs_link', type: 'combo', choices : ['static',
> 'shared', 'dlopen'],  option('include_subdir_arch', type: 'string', value: '',
>  	description: 'subdirectory where to install arch-dependent headers')
> option('kernel_dir', type: 'string', value: '',
> -	description: 'Path to the kernel for building kernel modules. Headers
> must be in $kernel_dir/build. Modules will be installed in
> $DEST_DIR/$kernel_dir/extra/dpdk.')
> +	description: 'Path to the kernel for building kernel modules. Headers
> +must be in $kernel_dir or $kernel_dir/build. Modules will be installed
> +in /lib/modules.')
>  option('machine', type: 'string', value: 'native',
>  	description: 'set the target machine type')  option('max_ethports', type:
> 'integer', value: 32,
> --
> 2.20.1