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From: "H. Peter Anvin" <hpa@zytor.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Richard Weinberger <richard@nod.at>,
	Linux-Arch <linux-arch@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Arnd Bergmann <arnd@arndb.de>
Subject: Re: VERIFY_READ/WRITE in uaccess.h?
Date: Mon, 11 May 2015 22:47:19 -0700	[thread overview]
Message-ID: <555193E7.30600@zytor.com> (raw)
In-Reply-To: <CA+55aFzF+Wo7EVSoJSaarbsQCNw5St4JH27t6vxNJivJnBQ0Sg@mail.gmail.com>

On 05/11/2015 02:42 PM, Linus Torvalds wrote:
> 
> That one - for the same reasons - also checked the actual accesses,
> not just that the range was in user mode. Exactly because it needed to
> pre-COW the pages (even if that was then obviously racy in threaded
> environments - in practice it worked, and we tried to support the
> fundamentally broken i386 hardware protection model for a long time).
> 

It worked in part because we never supported SMP on i386.

	-hpa

      reply	other threads:[~2015-05-12  5:47 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-10  9:44 VERIFY_READ/WRITE in uaccess.h? Richard Weinberger
2015-05-11 21:05 ` H. Peter Anvin
2015-05-11 21:26   ` Richard Weinberger
2015-05-11 21:42   ` Linus Torvalds
2015-05-12  5:47     ` H. Peter Anvin [this message]

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