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Subject: Re: [PATCH v2] MIPS/bpf: Enable bpf_probe_read{, str}() on MIPS again
To:     Thomas Bogendoerfer <tsbogend@alpha.franken.de>
References: <1616034557-5844-1-git-send-email-yangtiezhu@loongson.cn>
 <alpine.DEB.2.21.2103220540591.21463@angie.orcam.me.uk>
 <f36f4ca6-a3bb-8db9-01e6-65fec0916b58@loongson.cn>
 <20210325101712.GA6893@alpha.franken.de>
Cc:     "Maciej W. Rozycki" <macro@orcam.me.uk>,
        linux-mips@vger.kernel.org, bpf@vger.kernel.org,
        linux-kernel@vger.kernel.org, Xuefeng Li <lixuefeng@loongson.cn>,
        Christoph Hellwig <hch@lst.de>
From:   Tiezhu Yang <yangtiezhu@loongson.cn>
Message-ID: <38cf6f7c-28dd-20a0-8193-776fa7bdb83a@loongson.cn>
Date:   Thu, 25 Mar 2021 20:18:52 +0800
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On 03/25/2021 06:17 PM, Thomas Bogendoerfer wrote:
> On Mon, Mar 22, 2021 at 03:12:59PM +0800, Tiezhu Yang wrote:
>> On 03/22/2021 12:46 PM, Maciej W. Rozycki wrote:
>>> On Thu, 18 Mar 2021, Tiezhu Yang wrote:
>>>
>>>> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
>>>> index 160b3a8..4b94ec7 100644
>>>> --- a/arch/mips/Kconfig
>>>> +++ b/arch/mips/Kconfig
>>>> @@ -6,6 +6,7 @@ config MIPS
>>>>    	select ARCH_BINFMT_ELF_STATE if MIPS_FP_SUPPORT
>>>>    	select ARCH_HAS_FORTIFY_SOURCE
>>>>    	select ARCH_HAS_KCOV
>>>> +	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
>>>    Hmm, documentation on ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE seems rather
>>> scarce, but based on my guess shouldn't this be "if !EVA"?
>>>
>>>     Maciej
>> I do not quite know what the effect if MIPS EVA (Enhanced Virtual
>> Addressing)
>> is set, I saw that ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE should be
>> restricted
>> to archs with non-overlapping address ranges.
>>
>> I wonder whether MIPS EVA will generate overlapping address ranges?
> they can overlap in EVA mode.
>
>> If yes, it is better to make ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE depend
>> on !EVA on MIPS.
> Could please add the change ?

OK, thank you, I will do it soon.

>
> Thomas.
>