Re: [PATCH v4l-utils] Add missing linux/bpf_common.h

[Peter Seiderer <ps.report@gmx.net>]

Hello Sean,

On Tue, 6 Nov 2018 10:38:56 +0000, Sean Young <sean@mess.org> wrote:

> On Mon, Nov 05, 2018 at 09:30:47PM +0100, Peter Seiderer wrote:
> > Copy from [1], needed by bpf.h.
> >
> > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/plain/include/uapi/linux/bpf_common.h?h=v4.19
>
> So bpf.h does include this file, but we don't use anything from it in
> v4l-utils.
>

Maybe alternative fix is to remove the include (or not if your want
the headers to be in sync with the kernel ones, but then they should
be complete enough to be used for compile)?

> This include file is for the original BPF, which has been around for a
> long time. So why is this include file missing, i.e. what problem are you
> trying to solve?

A buildroot autobuild failure (see [1] for details) with older toolchains
not providing this header...

>
> Lastely, the file should be included in the sync-with-kernel target so
> it does not get out of sync -- should it really be necessary to add the
> file.

O.k, can do it on next patch iteration...

Regards,
Peter

[1] http://lists.busybox.net/pipermail/buildroot/2018-November/234840.html

>
>
> Sean
>
> >
> > Signed-off-by: Peter Seiderer <ps.report@gmx.net>
> > ---
> >  include/linux/bpf_common.h | 57 ++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 57 insertions(+)
> >  create mode 100644 include/linux/bpf_common.h
> >
> > diff --git a/include/linux/bpf_common.h b/include/linux/bpf_common.h
> > new file mode 100644
> > index 00000000..ee97668b
> > --- /dev/null
> > +++ b/include/linux/bpf_common.h
> > @@ -0,0 +1,57 @@
> > +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> > +#ifndef _UAPI__LINUX_BPF_COMMON_H__
> > +#define _UAPI__LINUX_BPF_COMMON_H__
> > +
> > +/* Instruction classes */
> > +#define BPF_CLASS(code) ((code) & 0x07)
> > +#define		BPF_LD		0x00
> > +#define		BPF_LDX		0x01
> > +#define		BPF_ST		0x02
> > +#define		BPF_STX		0x03
> > +#define		BPF_ALU		0x04
> > +#define		BPF_JMP		0x05
> > +#define		BPF_RET		0x06
> > +#define		BPF_MISC        0x07
> > +
> > +/* ld/ldx fields */
> > +#define BPF_SIZE(code)  ((code) & 0x18)
> > +#define		BPF_W		0x00 /* 32-bit */
> > +#define		BPF_H		0x08 /* 16-bit */
> > +#define		BPF_B		0x10 /*  8-bit */
> > +/* eBPF		BPF_DW		0x18    64-bit */
> > +#define BPF_MODE(code)  ((code) & 0xe0)
> > +#define		BPF_IMM		0x00
> > +#define		BPF_ABS		0x20
> > +#define		BPF_IND		0x40
> > +#define		BPF_MEM		0x60
> > +#define		BPF_LEN		0x80
> > +#define		BPF_MSH		0xa0
> > +
> > +/* alu/jmp fields */
> > +#define BPF_OP(code)    ((code) & 0xf0)
> > +#define		BPF_ADD		0x00
> > +#define		BPF_SUB		0x10
> > +#define		BPF_MUL		0x20
> > +#define		BPF_DIV		0x30
> > +#define		BPF_OR		0x40
> > +#define		BPF_AND		0x50
> > +#define		BPF_LSH		0x60
> > +#define		BPF_RSH		0x70
> > +#define		BPF_NEG		0x80
> > +#define		BPF_MOD		0x90
> > +#define		BPF_XOR		0xa0
> > +
> > +#define		BPF_JA		0x00
> > +#define		BPF_JEQ		0x10
> > +#define		BPF_JGT		0x20
> > +#define		BPF_JGE		0x30
> > +#define		BPF_JSET        0x40
> > +#define BPF_SRC(code)   ((code) & 0x08)
> > +#define		BPF_K		0x00
> > +#define		BPF_X		0x08
> > +
> > +#ifndef BPF_MAXINSNS
> > +#define BPF_MAXINSNS 4096
> > +#endif
> > +
> > +#endif /* _UAPI__LINUX_BPF_COMMON_H__ */
> > --
> > 2.19.1