Messages in this thread | | | Date | Sat, 28 Feb 2009 23:08:29 +0100 | From | Pavel Machek <> | Subject | Re: [PATCH 4/6] ftrace, x86: make kernel text writable only for conversions |
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> > > The very old text poke code I had for this just used a dynamic > > > mapping elsewhere instead to modify the code. That's much less > > > intrusive than changing the complete mappings. Any reason you can't use > > > that too? > > > > Is it legal to have two mappings of same page with different > > attributes? IIRC some processors did not like that... > > If you mean PAT caching attributes: correct it is not legal in x86 and > causes problems including data corruption.
Aha, PAT is what I remembered on x86-64.
> If you mean other attributes like large page vs small page: it's normally legal, > with a few exceptions.
...but is it okay on other architectures, like sparc, with funky cache setups? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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