linux-kernel - Re: [PATCHv2 0/7] eBPF JIT for PPC64

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Date:	Thu, 30 Jun 2016 12:34:33 +0300
From:	Denis Kirjanov <kda@...ux-powerpc.org>
To:	Andreas Ziegler <andreas.ziegler@....de>
Cc:	"Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com>,
	linuxppc-dev@...ts.ozlabs.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCHv2 0/7] eBPF JIT for PPC64

On 6/30/16, Andreas Ziegler <andreas.ziegler@....de> wrote:
> Hi Naveen,
>
> this patchset makes a change to arch/powerpc/net/Makefile in order to only
> compile the previously existing bpf_jit_comp.c if !CONFIG_PPC64, and use
> bpf_jit_comp64.c if CONFIG_PPC64 is enabled.
>
> Inside arch/powerpc/net/bpf_jit_comp.c, however, there is still an #ifdef
> CONFIG_PPC64 block at line 667 (linux-next of today, i.e., next-20160630):
>
>   #ifdef CONFIG_PPC64
>                   /* Function descriptor nastiness: Address + TOC */
>                   ((u64 *)image)[0] = (u64)code_base;
>                   ((u64 *)image)[1] = local_paca->kernel_toc;
>   #endif
>
> From my understanding of the code, this #ifdef can now be removed, as there
> is
> no way the file could be compiled with CONFIG_PPC64 enabled. Is this
> correct?

That was used for running classic BPF on ppc64. With eBPF on ppc64 the
whole block can be removed.

>
> Best regards,
>
> Andreas
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