From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Jack Steiner <steiner@sgi.com>,
mingo@elte.hu, tglx@linutronix.de, lenb@kernel.org,
linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC] - Mapping ACPI tables as CACHED
Date: Sat, 24 Jul 2010 01:45:32 +0100 [thread overview]
Message-ID: <20100724004532.GA9240@srcf.ucam.org> (raw)
In-Reply-To: <20100724001449.GA9618@khazad-dum.debian.net>
On Fri, Jul 23, 2010 at 09:14:50PM -0300, Henrique de Moraes Holschuh wrote:
> Well, as it was raised in this thread, ACPI tables are likely to be near RAM
> regions used for IPC with the firmware or SMBIOS, and we have no idea of the
> kind of crap that could happen if we enable caching on those areas.
>
> OTOH, we *know* of systems that force us to copy the ACPI tables to regular
> RAM, otherwise, the utterly broken BIOS corrupts the ACPI tables after the
> kernel has loaded.
>
> Couldn't we simply always copy all tables to regular RAM and mark THAT as
> cacheable (since there will be no IPC regions in it)? For the tables that
> are only used once, we can free the RAM later.
I think this is reasonable. There's an argument that we shouldn't cache
operation regions that may be sitting next to the ACPI tables, but I
can't see any problems being caused by copying the tables to RAM.
--
Matthew Garrett | mjg59@srcf.ucam.org
next prev parent reply other threads:[~2010-07-24 0:45 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-22 15:22 [RFC] - Mapping ACPI tables as CACHED Jack Steiner
2010-07-22 15:52 ` Len Brown
2010-07-23 16:38 ` Jack Steiner
2010-07-23 1:46 ` ykzhao
2010-07-23 7:23 ` Ingo Molnar
2010-07-23 14:26 ` ykzhao
2010-08-17 14:45 ` Jack Steiner
2010-08-17 15:51 ` H. Peter Anvin
2010-08-17 14:42 ` Jack Steiner
2010-08-17 14:39 ` Jack Steiner
2010-07-24 0:14 ` Henrique de Moraes Holschuh
2010-07-24 0:45 ` Matthew Garrett [this message]
2010-07-24 12:26 ` Henrique de Moraes Holschuh
2010-08-17 14:49 ` Jack Steiner
2010-08-17 16:02 ` Linus Torvalds
2010-08-24 21:39 ` H. Peter Anvin
2010-08-26 17:17 ` [RFC - V2] " Jack Steiner
2010-08-26 18:08 ` H. Peter Anvin
2010-12-08 21:22 ` Jack Steiner
2010-12-09 1:27 ` H. Peter Anvin
2010-12-09 3:50 ` Jack Steiner
2010-12-09 6:12 ` Len Brown
2010-08-17 15:59 ` [RFC] " Jack Steiner
2010-08-26 17:47 ` Len Brown
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