* [PATCH bpf-next] bpf_helpers.h: Add note for building with vmlinux.h or linux/types.h
@ 2020-04-21 0:05 Yoshiki Komachi
2020-04-21 1:56 ` Andrii Nakryiko
2020-04-23 5:27 ` Alexei Starovoitov
0 siblings, 2 replies; 3+ messages in thread
From: Yoshiki Komachi @ 2020-04-21 0:05 UTC (permalink / raw)
To: David S. Miller, Alexei Starovoitov, Daniel Borkmann,
Martin KaFai Lau, Song Liu, Yonghong Song, Andrii Nakryiko
Cc: Yoshiki Komachi, netdev, bpf
The following error was shown when a bpf program was compiled without
vmlinux.h auto-generated from BTF:
# clang -I./linux/tools/lib/ -I/lib/modules/$(uname -r)/build/include/ \
-O2 -Wall -target bpf -emit-llvm -c bpf_prog.c -o bpf_prog.bc
...
In file included from linux/tools/lib/bpf/bpf_helpers.h:5:
linux/tools/lib/bpf/bpf_helper_defs.h:56:82: error: unknown type name '__u64'
...
It seems that bpf programs are intended for being built together with
the vmlinux.h (which will have all the __u64 and other typedefs). But
users may mistakenly think "include <linux/types.h>" is missing
because the vmlinux.h is not common for non-bpf developers. IMO, an
explicit comment therefore should be added to bpf_helpers.h as this
patch shows.
Signed-off-by: Yoshiki Komachi <komachi.yoshiki@gmail.com>
---
tools/lib/bpf/bpf_helpers.h | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
index f69cc208778a..60aad054eea1 100644
--- a/tools/lib/bpf/bpf_helpers.h
+++ b/tools/lib/bpf/bpf_helpers.h
@@ -2,6 +2,12 @@
#ifndef __BPF_HELPERS__
#define __BPF_HELPERS__
+/*
+ * Note that bpf programs need to include either
+ * vmlinux.h (auto-generated from BTF) or linux/types.h
+ * in advance since bpf_helper_defs.h uses such types
+ * as __u64.
+ */
#include "bpf_helper_defs.h"
#define __uint(name, val) int (*name)[val]
--
2.24.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next] bpf_helpers.h: Add note for building with vmlinux.h or linux/types.h
2020-04-21 0:05 [PATCH bpf-next] bpf_helpers.h: Add note for building with vmlinux.h or linux/types.h Yoshiki Komachi
@ 2020-04-21 1:56 ` Andrii Nakryiko
2020-04-23 5:27 ` Alexei Starovoitov
1 sibling, 0 replies; 3+ messages in thread
From: Andrii Nakryiko @ 2020-04-21 1:56 UTC (permalink / raw)
To: Yoshiki Komachi
Cc: David S. Miller, Alexei Starovoitov, Daniel Borkmann,
Martin KaFai Lau, Song Liu, Yonghong Song, Andrii Nakryiko,
Networking, bpf
On Mon, Apr 20, 2020 at 5:06 PM Yoshiki Komachi
<komachi.yoshiki@gmail.com> wrote:
>
> The following error was shown when a bpf program was compiled without
> vmlinux.h auto-generated from BTF:
>
> # clang -I./linux/tools/lib/ -I/lib/modules/$(uname -r)/build/include/ \
> -O2 -Wall -target bpf -emit-llvm -c bpf_prog.c -o bpf_prog.bc
> ...
> In file included from linux/tools/lib/bpf/bpf_helpers.h:5:
> linux/tools/lib/bpf/bpf_helper_defs.h:56:82: error: unknown type name '__u64'
> ...
>
> It seems that bpf programs are intended for being built together with
> the vmlinux.h (which will have all the __u64 and other typedefs). But
> users may mistakenly think "include <linux/types.h>" is missing
> because the vmlinux.h is not common for non-bpf developers. IMO, an
> explicit comment therefore should be added to bpf_helpers.h as this
> patch shows.
>
> Signed-off-by: Yoshiki Komachi <komachi.yoshiki@gmail.com>
> ---
LGTM.
Acked-by: Andrii Nakryiko <andriin@fb.com>
> tools/lib/bpf/bpf_helpers.h | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
> index f69cc208778a..60aad054eea1 100644
> --- a/tools/lib/bpf/bpf_helpers.h
> +++ b/tools/lib/bpf/bpf_helpers.h
> @@ -2,6 +2,12 @@
> #ifndef __BPF_HELPERS__
> #define __BPF_HELPERS__
>
> +/*
> + * Note that bpf programs need to include either
> + * vmlinux.h (auto-generated from BTF) or linux/types.h
> + * in advance since bpf_helper_defs.h uses such types
> + * as __u64.
> + */
> #include "bpf_helper_defs.h"
>
> #define __uint(name, val) int (*name)[val]
> --
> 2.24.1
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next] bpf_helpers.h: Add note for building with vmlinux.h or linux/types.h
2020-04-21 0:05 [PATCH bpf-next] bpf_helpers.h: Add note for building with vmlinux.h or linux/types.h Yoshiki Komachi
2020-04-21 1:56 ` Andrii Nakryiko
@ 2020-04-23 5:27 ` Alexei Starovoitov
1 sibling, 0 replies; 3+ messages in thread
From: Alexei Starovoitov @ 2020-04-23 5:27 UTC (permalink / raw)
To: Yoshiki Komachi
Cc: David S. Miller, Alexei Starovoitov, Daniel Borkmann,
Martin KaFai Lau, Song Liu, Yonghong Song, Andrii Nakryiko,
Network Development, bpf
On Mon, Apr 20, 2020 at 5:05 PM Yoshiki Komachi
<komachi.yoshiki@gmail.com> wrote:
>
> The following error was shown when a bpf program was compiled without
> vmlinux.h auto-generated from BTF:
>
> # clang -I./linux/tools/lib/ -I/lib/modules/$(uname -r)/build/include/ \
> -O2 -Wall -target bpf -emit-llvm -c bpf_prog.c -o bpf_prog.bc
> ...
> In file included from linux/tools/lib/bpf/bpf_helpers.h:5:
> linux/tools/lib/bpf/bpf_helper_defs.h:56:82: error: unknown type name '__u64'
> ...
>
> It seems that bpf programs are intended for being built together with
> the vmlinux.h (which will have all the __u64 and other typedefs). But
> users may mistakenly think "include <linux/types.h>" is missing
> because the vmlinux.h is not common for non-bpf developers. IMO, an
> explicit comment therefore should be added to bpf_helpers.h as this
> patch shows.
>
> Signed-off-by: Yoshiki Komachi <komachi.yoshiki@gmail.com>
Applied. Thanks
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-04-21 0:05 [PATCH bpf-next] bpf_helpers.h: Add note for building with vmlinux.h or linux/types.h Yoshiki Komachi
2020-04-21 1:56 ` Andrii Nakryiko
2020-04-23 5:27 ` Alexei Starovoitov
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