[Buildroot] [PATCH v4 3/4] package/libbpf: new package

[Romain Naour]

Hello Qais,

Le 29/11/2020 à 16:27, Qais Yousef a écrit :
> Hi Romain
> 
> Shiny new package! Should we add a couple of sentences about the package in the
> commit message rather than leaving it empty?

I can copy past the Config.in help text:

	  libbpf library.
	  A mirror of bpf-next linux tree bpf-next/tools/lib/bpf
	  directory plus its supporting header files. The version
	  of the package reflects the version of ABI.

I don't have much to say.
Maybe that building libbpf from the kernel source (as linux-tools package) failed.

> 
> I haven't tested it yet, but a courtesy look at the patch it looked fine to me
> in general. I haven't played much with libbpf to test this. Is it supposed to
> completely replace BCC to compile and load bpf code, or just used to compile
> BPF code?

No, bcc and bpf are two different projects. bpf will not replace bcc.
Actually bcc git tree contain libbpf as a git soubmodule src/cc/libbpf.

Best regards,
Romain

> 
> Thanks
> 
> --
> Qais Yousef
> 
> On 11/07/20 01:28, Romain Naour wrote:
>> Signed-off-by: Jugurtha BELKALEM <jugurtha.belkalem at smile.fr>
>> Signed-off-by: Romain Naour <romain.naour at gmail.com>
>> Cc: Qais Yousef <qais.yousef at arm.com>
>> ---
>>  package/Config.in        |  1 +
>>  package/libbpf/Config.in | 20 ++++++++++++++++++++
>>  package/libbpf/libbpf.mk | 40 ++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 61 insertions(+)
>>  create mode 100644 package/libbpf/Config.in
>>  create mode 100644 package/libbpf/libbpf.mk
>>
>> diff --git a/package/Config.in b/package/Config.in
>> index 27d201cfd2..c0b8b06846 100644
>> --- a/package/Config.in
>> +++ b/package/Config.in
>> @@ -107,6 +107,7 @@ menu "Debugging, profiling and benchmark"
>>  	source "package/kvm-unit-tests/Config.in"
>>  	source "package/kyua/Config.in"
>>  	source "package/latencytop/Config.in"
>> +	source "package/libbpf/Config.in"
>>  	source "package/lmbench/Config.in"
>>  	source "package/lsof/Config.in"
>>  	source "package/ltp-testsuite/Config.in"
>> diff --git a/package/libbpf/Config.in b/package/libbpf/Config.in
>> new file mode 100644
>> index 0000000000..c5b24c5eb5
>> --- /dev/null
>> +++ b/package/libbpf/Config.in
>> @@ -0,0 +1,20 @@
>> +config BR2_PACKAGE_LIBBPF
>> +	bool "libbpf"
>> +	depends on BR2_USE_WCHAR # elfutils
>> +	depends on !BR2_STATIC_LIBS # elfutils
>> +	depends on BR2_TOOLCHAIN_HAS_THREADS # elfutils
>> +	depends on BR2_TOOLCHAIN_USES_UCLIBC || BR2_TOOLCHAIN_USES_GLIBC # elfutils
>> +	select BR2_PACKAGE_ELFUTILS
>> +	select BR2_PACKAGE_ZLIB
>> +	help
>> +	  libbpf library.
>> +	  A mirror of bpf-next linux tree bpf-next/tools/lib/bpf
>> +	  directory plus its supporting header files. The version
>> +	  of the package reflects the version of ABI.
>> +
>> +	  https://github.com/libbpf/libbpf
>> +
>> +comment "libbpf needs a uClibc or glibc toolchain w/ wchar, dynamic library, threads"
>> +	depends on !BR2_USE_WCHAR || BR2_STATIC_LIBS \
>> +		|| !BR2_TOOLCHAIN_HAS_THREADS \
>> +		|| !(BR2_TOOLCHAIN_USES_UCLIBC || BR2_TOOLCHAIN_USES_GLIBC)
>> diff --git a/package/libbpf/libbpf.mk b/package/libbpf/libbpf.mk
>> new file mode 100644
>> index 0000000000..33e303db16
>> --- /dev/null
>> +++ b/package/libbpf/libbpf.mk
>> @@ -0,0 +1,40 @@
>> +################################################################################
>> +#
>> +# libbpf
>> +#
>> +################################################################################
>> +
>> +LIBBPF_VERSION = 0.2
>> +LIBBPF_SITE = $(call github,libbpf,libbpf,v$(LIBBPF_VERSION))
>> +LIBBPF_LICENSE = GPL-2.0, LGPL-2.1, BSD-2-Clause
>> +LIBBPF_LICENSE_FILES = LICENSE LICENSE.BSD-2-Clause LICENSE.LPGL-2.1
>> +LIBBPF_DEPENDENCIES = host-bison host-flex host-pkgconf elfutils zlib
>> +LIBBPF_INSTALL_STAGING = YES
>> +
>> +define LIBBPF_BUILD_CMDS
>> +	$(TARGET_MAKE_ENV) $(TARGET_CONFIGURE_OPTS) $(MAKE) \
>> +		-C $(@D)/src
>> +endef
>> +
>> +# bpf/bpf.h installed by libbpf use enm bpf_iter_link_info that was added since
>> +# kernel 5.9, so we need to update some uapi headers in STAGING_DIR if the
>> +# toolchain is build with linux-headers < 5.9.
>> +# Otherwise bpf/bpf.h is broken due to out of date linux/bpf.h installed by the
>> +# toolchain.
>> +# https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a5cbe05a6673b85bed2a63ffcfea6a96c6410cff
>> +ifeq ($(BR2_TOOLCHAIN_HEADERS_AT_LEAST_5_9),)
>> +LIBBPF_UPDATE_UAPI_HEADERS = install_uapi_headers
>> +endif
>> +
>> +define LIBBPF_INSTALL_STAGING_CMDS
>> +	$(TARGET_MAKE_ENV) $(TARGET_CONFIGURE_OPTS) $(MAKE) \
>> +		-C $(@D)/src install $(LIBBPF_UPDATE_UAPI_HEADERS) \
>> +		DESTDIR=$(STAGING_DIR)
>> +endef
>> +
>> +define LIBBPF_INSTALL_TARGET_CMDS
>> +	$(TARGET_MAKE_ENV) $(TARGET_CONFIGURE_OPTS) $(MAKE) \
>> +		-C $(@D)/src install DESTDIR=$(TARGET_DIR)
>> +endef
>> +
>> +$(eval $(generic-package))
>> -- 
>> 2.25.4
>>