From: David Laight <David.Laight@ACULAB.COM>
To: openrisc@lists.librecores.org
Subject: [OpenRISC] [PATCH 04/14] x86: use more conventional access_ok() definition
Date: Mon, 14 Feb 2022 22:13:34 +0000 [thread overview]
Message-ID: <2dda07f893cb4ef9b5ea2265adccb98f@AcuMS.aculab.com> (raw)
In-Reply-To: <CAHk-=wgYu67OwP4LhcrPdDVxv2mOsx-Xsc2DKoVW6GZwKFtOYQ@mail.gmail.com>
From: Linus Torvalds
> Sent: 14 February 2022 20:24
> >
> > x86-64 has always(*) used TASK_SIZE_MAX for access_ok(), and the
> > get_user() assembler implementation does the same.
>
> Side note: we could just check the sign bit instead, and avoid big
> constants that way.
The cheap test for most 64bit is (addr | size) >> 62 != 0.
I did some tests last week and the compilers correctly optimise
out constant size.
Doesn't sparc64 still need a wrap test?
Or is that assumed because there is always an unmapped page
and transfer are 'adequately' done on increasing addresses?
David
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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2022-02-14 22:13 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-14 16:34 [OpenRISC] [PATCH 00/14] clean up asm/uaccess.h, kill set_fs for good Arnd Bergmann
2022-02-14 16:34 ` [OpenRISC] [PATCH 01/14] uaccess: fix integer overflow on access_ok() Arnd Bergmann
2022-02-14 16:58 ` Christoph Hellwig
2022-02-14 16:34 ` [OpenRISC] [PATCH 02/14] sparc64: add __{get, put}_kernel_nocheck() Arnd Bergmann
2022-02-14 16:34 ` [OpenRISC] [PATCH 03/14] nds32: fix access_ok() checks in get/put_user Arnd Bergmann
2022-02-14 17:01 ` Christoph Hellwig
2022-02-14 17:10 ` David Laight
2022-02-15 9:18 ` Arnd Bergmann
2022-02-15 10:25 ` Greg KH
2022-02-14 16:34 ` [OpenRISC] [PATCH 04/14] x86: use more conventional access_ok() definition Arnd Bergmann
2022-02-14 17:02 ` Christoph Hellwig
2022-02-14 19:45 ` Arnd Bergmann
2022-02-14 20:00 ` Christoph Hellwig
2022-02-14 20:01 ` Linus Torvalds
2022-02-14 20:17 ` Al Viro
2022-02-15 2:47 ` Al Viro
2022-02-14 20:24 ` Linus Torvalds
2022-02-14 22:13 ` David Laight [this message]
2022-02-14 16:34 ` [OpenRISC] [PATCH 05/14] uaccess: add generic __{get, put}_kernel_nofault Arnd Bergmann
2022-02-14 17:02 ` Christoph Hellwig
2022-02-15 0:31 ` Al Viro
2022-02-15 13:16 ` Arnd Bergmann
2022-02-14 16:34 ` [OpenRISC] [PATCH 06/14] mips: use simpler access_ok() Arnd Bergmann
2022-02-14 16:34 ` [OpenRISC] [PATCH 07/14] uaccess: generalize access_ok() Arnd Bergmann
2022-02-14 17:04 ` Christoph Hellwig
2022-02-14 17:15 ` Al Viro
2022-02-14 19:25 ` Arnd Bergmann
2022-02-15 10:58 ` Mark Rutland
2022-02-14 16:34 ` [OpenRISC] [PATCH 08/14] arm64: simplify access_ok() Arnd Bergmann
2022-02-14 21:06 ` Robin Murphy
2022-02-15 8:17 ` Ard Biesheuvel
2022-02-15 9:12 ` Arnd Bergmann
2022-02-15 9:21 ` Ard Biesheuvel
2022-02-15 9:39 ` Arnd Bergmann
2022-02-15 10:39 ` Mark Rutland
2022-02-15 10:37 ` Mark Rutland
2022-02-16 19:43 ` Christophe Leroy
2022-02-15 9:30 ` David Laight
2022-02-15 11:24 ` Mark Rutland
2022-02-15 11:07 ` Mark Rutland
2022-02-14 16:34 ` [OpenRISC] [PATCH 09/14] m68k: drop custom __access_ok() Arnd Bergmann
2022-02-15 0:37 ` Al Viro
2022-02-15 6:29 ` Christoph Hellwig
2022-02-15 7:13 ` Al Viro
2022-02-15 10:02 ` Arnd Bergmann
2022-02-15 13:28 ` David Laight
2022-02-14 16:34 ` [OpenRISC] [PATCH 10/14] uaccess: remove most CONFIG_SET_FS users Arnd Bergmann
2022-02-14 17:06 ` Christoph Hellwig
2022-02-14 19:40 ` Arnd Bergmann
2022-02-14 16:34 ` [OpenRISC] [PATCH 11/14] sparc64: remove CONFIG_SET_FS support Arnd Bergmann
2022-02-14 17:06 ` Christoph Hellwig
2022-02-16 13:06 ` Arnd Bergmann
2022-02-15 0:48 ` Al Viro
2022-02-16 13:07 ` Arnd Bergmann
2022-02-14 16:34 ` [OpenRISC] [PATCH 12/14] sh: " Arnd Bergmann
2022-02-14 16:34 ` [OpenRISC] [PATCH 13/14] ia64: " Arnd Bergmann
2022-02-14 16:34 ` [OpenRISC] [PATCH 14/14] uaccess: drop set_fs leftovers Arnd Bergmann
2022-02-15 3:03 ` Al Viro
2022-02-15 7:46 ` Helge Deller
2022-02-15 8:10 ` Arnd Bergmann
2022-02-14 17:35 ` [OpenRISC] [PATCH 00/14] clean up asm/uaccess.h, kill set_fs for good Linus Torvalds
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