From: Mark Rutland <mark.rutland@arm.com>
To: Arnd Bergmann <arnd@kernel.org>
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Subject: Re: [PATCH 08/14] arm64: simplify access_ok()
Date: Tue, 15 Feb 2022 10:39:06 +0000 [thread overview]
Message-ID: <YguCysZGYYWUhAPk@FVFF77S0Q05N> (raw)
In-Reply-To: <CAK8P3a0NTqK_m7q909d8FN6is8k4_u3zeckC9XOrjEi7kqSvmg@mail.gmail.com>
On Tue, Feb 15, 2022 at 10:39:46AM +0100, Arnd Bergmann wrote:
> On Tue, Feb 15, 2022 at 10:21 AM Ard Biesheuvel <ardb@kernel.org> wrote:
> > On Tue, 15 Feb 2022 at 10:13, Arnd Bergmann <arnd@kernel.org> wrote:
> >
> > arm64 also has this leading up to the range check, and I think we'd no
> > longer need it:
> >
> > if (IS_ENABLED(CONFIG_ARM64_TAGGED_ADDR_ABI) &&
> > (current->flags & PF_KTHREAD || test_thread_flag(TIF_TAGGED_ADDR)))
> > addr = untagged_addr(addr);
>
> I suspect the expensive part here is checking the two flags, as untagged_addr()
> seems to always just add a sbfx instruction. Would this work?
>
> #ifdef CONFIG_ARM64_TAGGED_ADDR_ABI
> #define access_ok(ptr, size) __access_ok(untagged_addr(ptr), (size))
> #else // the else path is the default, this can be left out.
> #define access_ok(ptr, size) __access_ok((ptr), (size))
> #endif
This would be an ABI change, e.g. for tasks without TIF_TAGGED_ADDR.
I don't think we should change this as part of this series.
Thanks,
Mark.
next prev parent reply other threads:[~2022-02-15 10:39 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-14 16:34 [PATCH 00/14] clean up asm/uaccess.h, kill set_fs for good Arnd Bergmann
2022-02-14 16:34 ` [PATCH 01/14] uaccess: fix integer overflow on access_ok() Arnd Bergmann
2022-02-14 16:58 ` Christoph Hellwig
2022-02-14 16:34 ` [PATCH 02/14] sparc64: add __{get,put}_kernel_nocheck() Arnd Bergmann
2022-02-14 16:34 ` [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 ` [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
2022-02-14 16:34 ` [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 ` [PATCH 06/14] mips: use simpler access_ok() Arnd Bergmann
2022-02-14 16:34 ` [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 ` [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 [this message]
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 ` [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 ` [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 ` [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 ` [PATCH 12/14] sh: " Arnd Bergmann
2022-02-14 16:34 ` [PATCH 13/14] ia64: " Arnd Bergmann
2022-02-14 16:34 ` [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 ` [PATCH 00/14] clean up asm/uaccess.h, kill set_fs for good Linus Torvalds
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