From: Johannes Berg <johannes@sipsolutions.net>
To: Philippe De Muyter <phdm@macqel.be>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: MPC8540 : What's "SPE used in kernel" ?
Date: Fri, 22 Feb 2008 16:29:11 +0100 [thread overview]
Message-ID: <1203694151.7082.37.camel@johannes.berg> (raw)
In-Reply-To: <20080222095022.GA635@ingate.macqel>
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> I wonder why a kernel configured for E500 and compiled by a E500-specific gcc
> triggers this message. Is it invalid to use SPE instructions in the kernel
> or do I misunderstand the message ?
I think it's like floating point/altivec, we don't always save the FP
registers on kernel/userspace transitions and so have to explicitly save
them to use them in the kernel, otherwise we'd clobber the userspace
register state.
I guess there's something like kernel_enter_spe()?
johannes
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next prev parent reply other threads:[~2008-02-22 15:29 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20080221123534.GA17716@ingate.macqel>
2008-02-22 9:50 ` MPC8540 : What's "SPE used in kernel" ? Philippe De Muyter
2008-02-22 15:29 ` Johannes Berg [this message]
2008-02-22 18:33 ` Andy Fleming
2008-02-23 9:24 ` Philippe De Muyter
2008-02-23 9:51 ` Johannes Berg
2008-02-23 10:17 ` Philippe De Muyter
2008-02-23 10:25 ` Johannes Berg
2008-02-26 7:39 ` Kumar Gala
2008-02-26 10:34 ` Philippe De Muyter
2008-02-25 14:47 ` E500 linux : are the 64-bit GPRs context-switched ? Philippe De Muyter
2008-02-25 16:58 ` Scott Wood
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