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From: Russell King <rmk@arm.linux.org.uk>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	James Bottomley <James.Bottomley@HansenPartnership.com>,
	linux-arch@vger.kernel.org
Subject: Re: [RFC PATCH 2/4] pio-mapping: Add ARM support for the PIO mapping API
Date: Wed, 17 Feb 2010 20:04:46 +0000	[thread overview]
Message-ID: <20100217200445.GA29249@flint.arm.linux.org.uk> (raw)
In-Reply-To: <1266397895.16346.267.camel@pasglop>

On Wed, Feb 17, 2010 at 08:11:35PM +1100, Benjamin Herrenschmidt wrote:
> In that case, I would recommend you look at how this is already dealt
> with on existing archs such as powerpc, using PG_arch1 in struct page to
> keep track of whether a given page is clean for execution and mapping
> pages that aren't non-exec so the kernel gets a chance to clean them
> once when execution happens.

That would be fine if we weren't already using PG_arch_1 for delaying
D-cache flushes for pages which aren't mapped, in the same way that
Sparc64 does.

That doesn't cover this case though - the problem is not I/D cache
coherency - the problem has manifested itself as data corruption when
userspace reads the page.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:

  reply	other threads:[~2010-02-17 20:08 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-05 16:31 [RFC PATCH 0/4] PIO drivers and cache coherency Catalin Marinas
2010-02-05 16:31 ` [RFC PATCH 1/4] pio-mapping: Add generic support for PIO mapping API Catalin Marinas
2010-02-05 16:31 ` [RFC PATCH 2/4] pio-mapping: Add ARM support for the " Catalin Marinas
2010-02-05 16:43   ` James Bottomley
2010-02-05 17:20     ` Catalin Marinas
2010-02-05 17:36       ` James Bottomley
2010-02-05 18:02         ` Catalin Marinas
2010-02-08 16:10         ` Catalin Marinas
2010-02-08 16:54           ` Russell King
2010-02-08 17:20             ` James Bottomley
2010-02-08 17:33               ` Russell King
2010-02-08 19:07                 ` James Bottomley
2010-02-08 18:02             ` [RFC PATCH 2/4] pio-mapping: Add ARM support for the PIOmapping API Catalin Marinas
2010-02-08 19:09               ` James Bottomley
2010-02-08 17:14           ` [RFC PATCH 2/4] pio-mapping: Add ARM support for the PIO mapping API James Bottomley
2010-02-09 18:03             ` Catalin Marinas
2010-02-17  9:11               ` Benjamin Herrenschmidt
2010-02-17 20:04                 ` Russell King [this message]
2010-02-17 20:39                   ` Benjamin Herrenschmidt
2010-02-05 16:32 ` [RFC PATCH 3/4] pio-mapping: Use the PIO mapping API in libata-sff.c Catalin Marinas
2010-02-05 16:32 ` [RFC PATCH 4/4] pio-mapping: Use the PIO mapping API in the ISP1760 HCD driver Catalin Marinas

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