From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 3 Mar 2003 19:54:05 -0500 From: Daniel Jacobowitz To: Dan Malek Cc: Joakim Tjernlund , linuxppc-dev@lists.linuxppc.org Subject: Re: Improved copy_page() function, about 30% speed up for mpc860! Message-ID: <20030304005405.GA29518@nevyn.them.org> References: <005401c2e0e4$27a1b6b0$020120b0@jockeXP> <3E63C6BE.6020002@embeddededge.com> <006a01c2e1da$e108ddd0$020120b0@jockeXP> <3E63F69C.80001@embeddededge.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <3E63F69C.80001@embeddededge.com> Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: On Mon, Mar 03, 2003 at 07:43:08PM -0500, Dan Malek wrote: > Joakim Tjernlund wrote: > > >OK so this is not it then, but what is it then? Are you 100% that > >the bug(whatever this may be) is present for mpc860, rev D4 or later? > >How can I make it bite me on kernel space memory? > >I can't find that info in the archives, if it's there please give me a > >hint. > > I guess once again I don't understand the questions or failed to express > my responses properly. > > In the previous message, you included a link that indicated a problem > setting the DAR, cache instructions, and asked if this was a problem. > In this case, due to the way we map kernel space and use the cache > instructions, > we have "fixed" this bug. I believe it was found because of the way we > copy instructions in the C library, and it affected user applications. > The specific problem described in this link is not a problem with Linux. That is, in fact, incorrect. It's fatal from userland. I experimented with it just a couple of months ago. Only way to sort it out would be to do instruction decoding on the faulting address, which is hideous beyond words. -- Daniel Jacobowitz MontaVista Software Debian GNU/Linux Developer ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/