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From: David Laight <David.Laight@ACULAB.COM>
To: 'Arnd Bergmann' <arnd@arndb.de>, Guo Ren <guoren@kernel.org>
Cc: linux-s390 <linux-s390@vger.kernel.org>,
	Guo Ren <guoren@linux.alibaba.com>,
	gregkh <gregkh@linuxfoundation.org>,
	Drew Fustini <drew@beagleboard.org>,
	Anup Patel <anup@brainfault.org>,
	Wang Junqiang <wangjunqiang@iscas.ac.cn>,
	the arch/x86 maintainers <x86@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"linux-csky@vger.kernel.org" <linux-csky@vger.kernel.org>,
	"inux-parisc@vger.kernel.org" <inux-parisc@vger.kernel.org>,
	Christoph Hellwig <hch@infradead.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	liush <liush@allwinnertech.com>,
	sparclinux <sparclinux@vger.kernel.org>,
	linux-riscv <linux-riscv@lists.infradead.org>,
	"open list:BROADCOM NVRAM DRIVER" <linux-mips@vger.kernel.org>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
	Christoph Hellwig <hch@lst.de>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Wei Fu <wefu@redhat.com>
Subject: RE: [PATCH V3 07/17] riscv: compat: Re-implement TASK_SIZE for COMPAT_32BIT
Date: Thu, 20 Jan 2022 12:53:11 +0000	[thread overview]
Message-ID: <f16cf10425a14c2e8183d5c90667ce72@AcuMS.aculab.com> (raw)
In-Reply-To: <CAK8P3a1UvqsS-D7cVXBkp4KCRWDfquQ6QTkvrQ=FqLxhsAi7Rw@mail.gmail.com>

> > Limit 32-bit compatible process in 0-2GB virtual address range
> > (which is enough for real scenarios), because it could avoid
> > address sign extend problem when 32-bit enter 64-bit and ease
> > software design.

Eh?
I thought nearly all the other 32bit unix ports (of any flavour)
put the user-kernel boundary at 3GB.
(Apart from some very old sparc ones that use 3.5GB.)

2GB is used by Windows.

I think the x86-64 32bit compat code even puts the boundary at 4GB.

	David

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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

  reply	other threads:[~2022-01-20 12:53 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-20  7:39 [PATCH V3 07/17] riscv: compat: Re-implement TASK_SIZE for COMPAT_32BIT guoren
2022-01-20  9:31 ` Arnd Bergmann
2022-01-20 12:53   ` David Laight [this message]
2022-01-20 13:27     ` Guo Ren
2022-01-20 14:57       ` Arnd Bergmann
2022-01-20 15:46         ` David Laight

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