From: Christoph Hellwig <hch@lst.de>
To: David Laight <David.Laight@ACULAB.COM>
Cc: 'Andy Lutomirski' <luto@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Al Viro <viro@zeniv.linux.org.uk>, X86 ML <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Will Deacon <will@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Waiman Long <longman@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Christoph Hellwig <hch@lst.de>,
Mark Rutland <mark.rutland@arm.com>,
Borislav Petkov <bp@alien8.de>
Subject: Re: [PATCH v4 3/4] x86/uaccess: Use pointer masking to limit uaccess speculation
Date: Thu, 6 May 2021 14:05:26 +0200 [thread overview]
Message-ID: <20210506120526.GA1124@lst.de> (raw)
In-Reply-To: <986301bcdc7c488d86dd5f11c988bf87@AcuMS.aculab.com>
On Thu, May 06, 2021 at 08:36:08AM +0000, David Laight wrote:
> uaddr = access_ok(uaddr, size)
access_ok as a public API is not interesting. There are very few
valid uses cases for ever calling access_ok outside the usual
uaccess helper. So leave access_ok alone, there is not point in
touching all the callers except for removing most of them. If OTOH
we can micro-optimize get_user and put_user by using a different
variant of access_ok that seems fair game and actually useful.
next prev parent reply other threads:[~2021-05-06 12:05 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-05 3:54 [PATCH v4 0/4] x86/uaccess: Use pointer masking to limit uaccess speculation Josh Poimboeuf
2021-05-05 3:54 ` [PATCH v4 1/4] uaccess: Always inline strn*_user() helper functions Josh Poimboeuf
2021-05-05 3:54 ` [PATCH v4 2/4] uaccess: Fix __user annotations for copy_mc_to_user() Josh Poimboeuf
2021-05-05 3:54 ` [PATCH v4 3/4] x86/uaccess: Use pointer masking to limit uaccess speculation Josh Poimboeuf
2021-05-05 8:48 ` David Laight
2021-05-05 13:19 ` Josh Poimboeuf
2021-05-05 13:51 ` David Laight
2021-05-05 18:32 ` Linus Torvalds
2021-05-06 7:57 ` David Laight
2021-05-05 14:25 ` Mark Rutland
2021-05-05 14:48 ` Josh Poimboeuf
2021-05-05 14:49 ` David Laight
2021-05-05 15:45 ` Mark Rutland
2021-05-05 16:55 ` Andy Lutomirski
2021-05-06 8:36 ` David Laight
2021-05-06 12:05 ` Christoph Hellwig [this message]
2021-06-02 17:11 ` Sean Christopherson
2021-06-02 20:11 ` Josh Poimboeuf
2021-05-05 3:54 ` [PATCH v4 4/4] x86/nospec: Remove barrier_nospec() Josh Poimboeuf
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