From: David Miller <davem@davemloft.net>
To: catalin.marinas@arm.com
Cc: matthew@wil.cx, fujita.tomonori@lab.ntt.co.jp,
linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
James.Bottomley@HansenPartnership.com, benh@kernel.crashing.org,
rmk@arm.linux.org.uk
Subject: Re: [RFC PATCH] Update the cachetlb.txt file WRT flush_dcache_pageand update_mmu_cache
Date: Mon, 10 May 2010 07:03:26 -0700 (PDT) [thread overview]
Message-ID: <20100510.070326.146087861.davem@davemloft.net> (raw)
In-Reply-To: <1273500010.10282.25.camel@e102109-lin.cambridge.arm.com>
From: Catalin Marinas <catalin.marinas@arm.com>
Date: Mon, 10 May 2010 15:00:10 +0100
> 3rd point above would help with the D-cache aliasing. Does the I/D cache
> coherency need to be handled differently? On PIPT Harvard architectures,
> we don't actually have D-cache aliasing but we may end up flushing too
> much in kunmap() just in case such page would be mapped in user space
> with executable permission.
You can handle this by having an "I-cache clean" bit in the page.
When you kmap/kunmap, simply force this bit clear.
In update_mmu_cache() or set_pte_at() you'll see when a page gets
into userspace with execute permission, and if the I-cache bit
is clear you can do the flush then and set the "I-cache clean"
bit.
next prev parent reply other threads:[~2010-05-10 14:03 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-07 13:24 [RFC PATCH] Update the cachetlb.txt file WRT flush_dcache_page and update_mmu_cache Catalin Marinas
2010-05-10 8:06 ` FUJITA Tomonori
2010-05-10 10:16 ` Catalin Marinas
2010-05-10 10:29 ` Paul Mundt
2010-05-10 14:40 ` James Bottomley
2010-05-10 14:40 ` James Bottomley
2010-05-10 11:55 ` Matthew Wilcox
2010-05-10 14:00 ` [RFC PATCH] Update the cachetlb.txt file WRT flush_dcache_pageand update_mmu_cache Catalin Marinas
2010-05-10 14:03 ` David Miller [this message]
2010-05-10 14:32 ` Catalin Marinas
2010-05-11 11:31 ` [RFC PATCH] Update the cachetlb.txt file WRT flush_dcache_page and update_mmu_cache FUJITA Tomonori
2010-05-11 17:22 ` Catalin Marinas
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