[GIT PULL 0/2] libbpf build fixes

[GIT PULL 0/2] libbpf build fixes

[Arnaldo Carvalho de Melo]

Hi Daniel,

	Please consider pulling or applying from the patches, if someone
has any issues, please holler,

- Arnaldo

Arnaldo Carvalho de Melo (2):
  libbpf: Fix endianness macro usage for some compilers
  libbpf: Avoid designated initializers for unnamed union members

 tools/lib/bpf/btf.c    |  5 +++--
 tools/lib/bpf/libbpf.c | 19 ++++++++++---------
 2 files changed, 13 insertions(+), 11 deletions(-)

-- 
2.21.0

The following changes since commit 9b3d15e6b05e0b916be5fbd915f90300a403098b:

  bnxt_en: Fix VNIC accounting when enabling aRFS on 57500 chips. (2019-07-18 16:33:27 -0700)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git libbpf

for you to fetch changes up to 5443fc23eb80e7cd03f9111fb16fb9aaa76fedc9:

  libbpf: Avoid designated initializers for unnamed union members (2019-07-19 11:21:33 -0300)

----------------------------------------------------------------
Arnaldo Carvalho de Melo (2):
      libbpf: Fix endianness macro usage for some compilers
      libbpf: Avoid designated initializers for unnamed union members

 tools/lib/bpf/btf.c    |  5 +++--
 tools/lib/bpf/libbpf.c | 19 ++++++++++---------
 2 files changed, 13 insertions(+), 11 deletions(-)

[PATCH 1/2] libbpf: Fix endianness macro usage for some compilers

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

Using endian.h and its endianness macros makes this code build in a
wider range of compilers, as some don't have those macros
(__BYTE_ORDER__, __ORDER_LITTLE_ENDIAN__, __ORDER_BIG_ENDIAN__),
so use instead endian.h's macros (__BYTE_ORDER, __LITTLE_ENDIAN,
__BIG_ENDIAN) which makes this code even shorter :-)

Acked-by: Andrii Nakryiko <andriin@fb.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Fixes: 12ef5634a855 ("libbpf: simplify endianness check")
Fixes: e6c64855fd7a ("libbpf: add btf__parse_elf API to load .BTF and .BTF.ext")
Link: https://lkml.kernel.org/n/tip-eep5n8vgwcdphw3uc058k03u@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/lib/bpf/btf.c    | 5 +++--
 tools/lib/bpf/libbpf.c | 5 +++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 467224feb43b..d821107f55f9 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
 /* Copyright (c) 2018 Facebook */
 
+#include <endian.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -419,9 +420,9 @@ struct btf *btf__new(__u8 *data, __u32 size)
 
 static bool btf_check_endianness(const GElf_Ehdr *ehdr)
 {
-#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#if __BYTE_ORDER == __LITTLE_ENDIAN
 	return ehdr->e_ident[EI_DATA] == ELFDATA2LSB;
-#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#elif __BYTE_ORDER == __BIG_ENDIAN
 	return ehdr->e_ident[EI_DATA] == ELFDATA2MSB;
 #else
 # error "Unrecognized __BYTE_ORDER__"
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 794dd5064ae8..b1dec5b1de54 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -20,6 +20,7 @@
 #include <inttypes.h>
 #include <string.h>
 #include <unistd.h>
+#include <endian.h>
 #include <fcntl.h>
 #include <errno.h>
 #include <asm/unistd.h>
@@ -612,10 +613,10 @@ static int bpf_object__elf_init(struct bpf_object *obj)
 
 static int bpf_object__check_endianness(struct bpf_object *obj)
 {
-#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#if __BYTE_ORDER == __LITTLE_ENDIAN
 	if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
 		return 0;
-#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#elif __BYTE_ORDER == __BIG_ENDIAN
 	if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
 		return 0;
 #else
-- 
2.21.0

[PATCH 2/2] libbpf: Avoid designated initializers for unnamed union members

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

As it fails to build in some systems with:

  libbpf.c: In function 'perf_buffer__new':
  libbpf.c:4515: error: unknown field 'sample_period' specified in initializer
  libbpf.c:4516: error: unknown field 'wakeup_events' specified in initializer

Doing as:

    attr.sample_period = 1;

I.e. not as a designated initializer makes it build everywhere.

Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Fixes: fb84b8224655 ("libbpf: add perf buffer API")
Link: https://lkml.kernel.org/n/tip-hnlmch8qit1ieksfppmr32si@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/lib/bpf/libbpf.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index b1dec5b1de54..aaca132def74 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4508,13 +4508,13 @@ struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
 				     const struct perf_buffer_opts *opts)
 {
 	struct perf_buffer_params p = {};
-	struct perf_event_attr attr = {
-		.config = PERF_COUNT_SW_BPF_OUTPUT,
-		.type = PERF_TYPE_SOFTWARE,
-		.sample_type = PERF_SAMPLE_RAW,
-		.sample_period = 1,
-		.wakeup_events = 1,
-	};
+	struct perf_event_attr attr = { 0, };
+
+	attr.config = PERF_COUNT_SW_BPF_OUTPUT,
+	attr.type = PERF_TYPE_SOFTWARE;
+	attr.sample_type = PERF_SAMPLE_RAW;
+	attr.sample_period = 1;
+	attr.wakeup_events = 1;
 
 	p.attr = &attr;
 	p.sample_cb = opts ? opts->sample_cb : NULL;
-- 
2.21.0

Re: [PATCH 1/2] libbpf: Fix endianness macro usage for some compilers

[Y Song]

On Fri, Jul 19, 2019 at 7:35 AM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> From: Arnaldo Carvalho de Melo <acme@redhat.com>
>
> Using endian.h and its endianness macros makes this code build in a
> wider range of compilers, as some don't have those macros
> (__BYTE_ORDER__, __ORDER_LITTLE_ENDIAN__, __ORDER_BIG_ENDIAN__),
> so use instead endian.h's macros (__BYTE_ORDER, __LITTLE_ENDIAN,
> __BIG_ENDIAN) which makes this code even shorter :-)

gcc 4.6.0 starts to support __BYTE_ORDER__, __ORDER_LITTLE_ENDIAN__, etc.
I guess those platforms with failing compilation have gcc < 4.6.0.
Agree that for libbpf, which will be used outside kernel bpf selftest should
try to compile with lower versions of gcc.

>
> Acked-by: Andrii Nakryiko <andriin@fb.com>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Alexei Starovoitov <ast@kernel.org>
> Cc: Daniel Borkmann <daniel@iogearbox.net>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Fixes: 12ef5634a855 ("libbpf: simplify endianness check")
> Fixes: e6c64855fd7a ("libbpf: add btf__parse_elf API to load .BTF and .BTF.ext")
> Link: https://lkml.kernel.org/n/tip-eep5n8vgwcdphw3uc058k03u@git.kernel.org
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
>  tools/lib/bpf/btf.c    | 5 +++--
>  tools/lib/bpf/libbpf.c | 5 +++--
>  2 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
> index 467224feb43b..d821107f55f9 100644
> --- a/tools/lib/bpf/btf.c
> +++ b/tools/lib/bpf/btf.c
> @@ -1,6 +1,7 @@
>  // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
>  /* Copyright (c) 2018 Facebook */
>
> +#include <endian.h>
>  #include <stdio.h>
>  #include <stdlib.h>
>  #include <string.h>
> @@ -419,9 +420,9 @@ struct btf *btf__new(__u8 *data, __u32 size)
>
>  static bool btf_check_endianness(const GElf_Ehdr *ehdr)
>  {
> -#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
> +#if __BYTE_ORDER == __LITTLE_ENDIAN
>         return ehdr->e_ident[EI_DATA] == ELFDATA2LSB;
> -#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
> +#elif __BYTE_ORDER == __BIG_ENDIAN
>         return ehdr->e_ident[EI_DATA] == ELFDATA2MSB;
>  #else
>  # error "Unrecognized __BYTE_ORDER__"
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 794dd5064ae8..b1dec5b1de54 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -20,6 +20,7 @@
>  #include <inttypes.h>
>  #include <string.h>
>  #include <unistd.h>
> +#include <endian.h>
>  #include <fcntl.h>
>  #include <errno.h>
>  #include <asm/unistd.h>
> @@ -612,10 +613,10 @@ static int bpf_object__elf_init(struct bpf_object *obj)
>
>  static int bpf_object__check_endianness(struct bpf_object *obj)
>  {
> -#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
> +#if __BYTE_ORDER == __LITTLE_ENDIAN
>         if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
>                 return 0;
> -#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
> +#elif __BYTE_ORDER == __BIG_ENDIAN
>         if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
>                 return 0;
>  #else
> --
> 2.21.0
>

Re: [PATCH 2/2] libbpf: Avoid designated initializers for unnamed union members

[Andrii Nakryiko]

On Fri, Jul 19, 2019 at 7:34 AM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> From: Arnaldo Carvalho de Melo <acme@redhat.com>
>
> As it fails to build in some systems with:
>
>   libbpf.c: In function 'perf_buffer__new':
>   libbpf.c:4515: error: unknown field 'sample_period' specified in initializer
>   libbpf.c:4516: error: unknown field 'wakeup_events' specified in initializer
>
> Doing as:
>
>     attr.sample_period = 1;
>
> I.e. not as a designated initializer makes it build everywhere.
>
> Cc: Andrii Nakryiko <andriin@fb.com>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Daniel Borkmann <daniel@iogearbox.net>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Fixes: fb84b8224655 ("libbpf: add perf buffer API")
> Link: https://lkml.kernel.org/n/tip-hnlmch8qit1ieksfppmr32si@git.kernel.org
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---

Thanks, Arnaldo!

Acked-by: Andrii Nakryiko <andriin@fb.com>

>  tools/lib/bpf/libbpf.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index b1dec5b1de54..aaca132def74 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -4508,13 +4508,13 @@ struct perf_buffer *perf_buffer__new(int map_fd, size_t page_cnt,
>                                      const struct perf_buffer_opts *opts)
>  {
>         struct perf_buffer_params p = {};
> -       struct perf_event_attr attr = {
> -               .config = PERF_COUNT_SW_BPF_OUTPUT,
> -               .type = PERF_TYPE_SOFTWARE,
> -               .sample_type = PERF_SAMPLE_RAW,
> -               .sample_period = 1,
> -               .wakeup_events = 1,
> -       };
> +       struct perf_event_attr attr = { 0, };
> +
> +       attr.config = PERF_COUNT_SW_BPF_OUTPUT,
> +       attr.type = PERF_TYPE_SOFTWARE;
> +       attr.sample_type = PERF_SAMPLE_RAW;
> +       attr.sample_period = 1;
> +       attr.wakeup_events = 1;
>
>         p.attr = &attr;
>         p.sample_cb = opts ? opts->sample_cb : NULL;
> --
> 2.21.0
>

Re: [PATCH 1/2] libbpf: Fix endianness macro usage for some compilers

[Arnaldo Carvalho de Melo]

Em Fri, Jul 19, 2019 at 09:25:07AM -0700, Y Song escreveu:
> On Fri, Jul 19, 2019 at 7:35 AM Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
> > Using endian.h and its endianness macros makes this code build in a
> > wider range of compilers, as some don't have those macros
> > (__BYTE_ORDER__, __ORDER_LITTLE_ENDIAN__, __ORDER_BIG_ENDIAN__),
> > so use instead endian.h's macros (__BYTE_ORDER, __LITTLE_ENDIAN,
> > __BIG_ENDIAN) which makes this code even shorter :-)
> 
> gcc 4.6.0 starts to support __BYTE_ORDER__, __ORDER_LITTLE_ENDIAN__, etc.
> I guess those platforms with failing compilation have gcc < 4.6.0.
> Agree that for libbpf, which will be used outside kernel bpf selftest should
> try to compile with lower versions of gcc.

Yeah, I wouldn't mind at all if the answer to this patch was hey, the
minimal version for building libbpf is X.Y, no problem, its just that in
this case there is an alternative that works everywhere and the
resulting source code is even more compact :-)

- Arnaldo
 
> > Acked-by: Andrii Nakryiko <andriin@fb.com>
> > Cc: Adrian Hunter <adrian.hunter@intel.com>
> > Cc: Alexei Starovoitov <ast@kernel.org>
> > Cc: Daniel Borkmann <daniel@iogearbox.net>
> > Cc: Jiri Olsa <jolsa@kernel.org>
> > Cc: Namhyung Kim <namhyung@kernel.org>
> > Fixes: 12ef5634a855 ("libbpf: simplify endianness check")
> > Fixes: e6c64855fd7a ("libbpf: add btf__parse_elf API to load .BTF and .BTF.ext")
> > Link: https://lkml.kernel.org/n/tip-eep5n8vgwcdphw3uc058k03u@git.kernel.org
> > Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> > ---
> >  tools/lib/bpf/btf.c    | 5 +++--
> >  tools/lib/bpf/libbpf.c | 5 +++--
> >  2 files changed, 6 insertions(+), 4 deletions(-)
> >
> > diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
> > index 467224feb43b..d821107f55f9 100644
> > --- a/tools/lib/bpf/btf.c
> > +++ b/tools/lib/bpf/btf.c
> > @@ -1,6 +1,7 @@
> >  // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
> >  /* Copyright (c) 2018 Facebook */
> >
> > +#include <endian.h>
> >  #include <stdio.h>
> >  #include <stdlib.h>
> >  #include <string.h>
> > @@ -419,9 +420,9 @@ struct btf *btf__new(__u8 *data, __u32 size)
> >
> >  static bool btf_check_endianness(const GElf_Ehdr *ehdr)
> >  {
> > -#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
> > +#if __BYTE_ORDER == __LITTLE_ENDIAN
> >         return ehdr->e_ident[EI_DATA] == ELFDATA2LSB;
> > -#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
> > +#elif __BYTE_ORDER == __BIG_ENDIAN
> >         return ehdr->e_ident[EI_DATA] == ELFDATA2MSB;
> >  #else
> >  # error "Unrecognized __BYTE_ORDER__"
> > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > index 794dd5064ae8..b1dec5b1de54 100644
> > --- a/tools/lib/bpf/libbpf.c
> > +++ b/tools/lib/bpf/libbpf.c
> > @@ -20,6 +20,7 @@
> >  #include <inttypes.h>
> >  #include <string.h>
> >  #include <unistd.h>
> > +#include <endian.h>
> >  #include <fcntl.h>
> >  #include <errno.h>
> >  #include <asm/unistd.h>
> > @@ -612,10 +613,10 @@ static int bpf_object__elf_init(struct bpf_object *obj)
> >
> >  static int bpf_object__check_endianness(struct bpf_object *obj)
> >  {
> > -#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
> > +#if __BYTE_ORDER == __LITTLE_ENDIAN
> >         if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2LSB)
> >                 return 0;
> > -#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
> > +#elif __BYTE_ORDER == __BIG_ENDIAN
> >         if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2MSB)
> >                 return 0;
> >  #else
> > --
> > 2.21.0
> >

-- 

- Arnaldo

Re: [GIT PULL 0/2] libbpf build fixes

[Daniel Borkmann]

On 7/19/19 4:34 PM, Arnaldo Carvalho de Melo wrote:
> Hi Daniel,
> 
> 	Please consider pulling or applying from the patches, if someone
> has any issues, please holler,
> 
> - Arnaldo
> 
> Arnaldo Carvalho de Melo (2):
>   libbpf: Fix endianness macro usage for some compilers
>   libbpf: Avoid designated initializers for unnamed union members
> 
>  tools/lib/bpf/btf.c    |  5 +++--
>  tools/lib/bpf/libbpf.c | 19 ++++++++++---------
>  2 files changed, 13 insertions(+), 11 deletions(-)
> 

Applied, thanks!