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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Mon, 11 Jun 2018 09:48:02 +0200
Message-ID: <CAK8P3a16ByPtCwKbdLQRDRni3qV9DXLNYZ9QJUH6uHaZYHr34g@mail.gmail.com>
Subject: Re: [PATCH 04/24] 32-bit userspace ABI: introduce ARCH_32BIT_OFF_T
 config option
To:     Yury Norov <ynorov@caviumnetworks.com>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
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        Szabolcs Nagy <szabolcs.nagy@arm.com>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
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        Bamvor Zhangjian <bamv2005@gmail.com>,
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On Sat, Jun 9, 2018 at 9:42 AM, Yury Norov <ynorov@caviumnetworks.com> wrote:
> On Fri, Jun 08, 2018 at 06:32:07PM +0100, Catalin Marinas wrote:
>> On Wed, May 16, 2018 at 11:18:49AM +0300, Yury Norov wrote:
>> > diff --git a/arch/Kconfig b/arch/Kconfig
>> > index 76c0b54443b1..ee079244dc3c 100644
>> > --- a/arch/Kconfig
>> > +++ b/arch/Kconfig
>> > @@ -264,6 +264,21 @@ config ARCH_THREAD_STACK_ALLOCATOR
>> >  config ARCH_WANTS_DYNAMIC_TASK_STRUCT
>> >     bool
>> >
>> > +config ARCH_32BIT_OFF_T
>> > +   bool
>> > +   depends on !64BIT
>> > +   help
>> > +     All new 32-bit architectures should have 64-bit off_t type on
>> > +     userspace side which corresponds to the loff_t kernel type. This
>> > +     is the requirement for modern ABIs. Some existing architectures
>> > +     already have 32-bit off_t. This option is enabled for all such
>> > +     architectures explicitly. Namely: arc, arm, blackfin, cris, frv,
>> > +     h8300, hexagon, m32r, m68k, metag, microblaze, mips32, mn10300,
>> > +     nios2, openrisc, parisc32, powerpc32, score, sh, sparc, tile32,
>> > +     unicore32, x86_32 and xtensa. This is the complete list. Any
>> > +     new 32-bit architecture should declare 64-bit off_t type on user
>> > +     side and so should not enable this option.
>>
>> Do you know if this is the case for riscv and nds32, merged in the
>> meantime? If not, I suggest you drop this patch altogether and just
>> define force_o_largefile() for arm64/ilp32 as we don't seem to stick to
>> "all new 32-bit architectures should have 64-bit off_t".
>
> I wrote this patch at request of Arnd Bergmann. This is actually his
> words that all new 32-bit architectures should have 64-bit off_t. So
> I was surprized when riscv was merged with 32-bit off_t (and I didn't
> follow nds32).
>
> If this rule is still in force, we'd better add new exceptions to this
> patch. Otherwise, we can drop it.
>
> Arnd, could you please comment it?

I completely forgot about it and had assumed that it was merged long
ago, sorry about that.

        Arnd