[PATCH] bpf: arm64: lift restriction on last instruction

Will Deacon will.deacon at arm.com
Wed Dec 3 10:04:52 PST 2014


On Wed, Dec 03, 2014 at 03:54:32PM +0000, Alexei Starovoitov wrote:
> On Wed, Dec 3, 2014 at 12:38 AM, Zi Shen Lim <zlim.lnx at gmail.com> wrote:
> > Earlier implementation assumed last instruction is BPF_EXIT.
> > Since this is no longer a restriction in eBPF, we remove this
> > limitation.
> >
> > Per Alexei Starovoitov [1]:
> >> classic BPF has a restriction that last insn is always BPF_RET.
> >> eBPF doesn't have BPF_RET instruction and this restriction.
> >> It has BPF_EXIT insn which can appear anywhere in the program
> >> one or more times and it doesn't have to be last insn.
> >
> > [1] https://lkml.org/lkml/2014/11/27/2
> >
> > Fixes: e54bcde3d69d ("arm64: eBPF JIT compiler")
> > Signed-off-by: Zi Shen Lim <zlim.lnx at gmail.com>
> 
> yours is cleaner than my own attempt to fix it.
> Thanks!
> Acked-by: Alexei Starovoitov <ast at plumgrid.com>

Cheers, I've applied this for 3.19.

Will



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