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Date:   Mon, 27 Feb 2023 15:47:05 +0000
From:   "Jiaxun Yang" <jiaxun.yang@flygoat.com>
To:     "Maciej W. Rozycki" <macro@orcam.me.uk>,
        "Johan Almbladh" <johan.almbladh@anyfinetworks.com>
Cc:     "linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>,
        linux-kernel@vger.kernel.org,
        "Thomas Bogendoerfer" <tsbogend@alpha.franken.de>,
        "paulburton@kernel.org" <paulburton@kernel.org>,
        bpf@vger.kernel.org, "Alexei Starovoitov" <ast@kernel.org>,
        "Andrii Nakryiko" <andrii@kernel.org>,
        "Daniel Borkmann" <daniel@iogearbox.net>
Subject: Re: [PATCH 2/2] MIPS: ebpf jit: Implement R4000 workarounds
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=E5=9C=A82023=E5=B9=B42=E6=9C=8827=E6=97=A5=E4=BA=8C=E6=9C=88 =E4=B8=8B=E5=
=8D=883:18=EF=BC=8CMaciej W. Rozycki=E5=86=99=E9=81=93=EF=BC=9A
> On Mon, 27 Feb 2023, Johan Almbladh wrote:
>
>> > > R4000 is a 64-bit CPU, so the 32-bit JIT implementation will not =
be
>> > > used. From the Makefile:
>> > >
>> > > ifeq ($(CONFIG_32BIT),y)
>> > >        obj-$(CONFIG_BPF_JIT) +=3D bpf_jit_comp32.o
>> > > else
>> > >        obj-$(CONFIG_BPF_JIT) +=3D bpf_jit_comp64.o
>> > > endif
>> >
>> > It=E2=80=99s common practice to run 32-bit kernel on R4000 based sy=
stems to save some memory :-)
>>=20
>> Ok, I understand.
>
>  Likewise:
>
> 	select CPU_R4000_WORKAROUNDS if 64BIT
> 	select CPU_R4400_WORKAROUNDS if 64BIT
>
> This only applies to 64-bit operations, which are not used in 32-bit c=
ode=20
> (one reason why these early silicon revisions were originally used wit=
h=20
> 32-bit software only).

Thanks for the info.
Will drop 32bit part from both patch.

>
>   Maciej

--=20
- Jiaxun