Messages in this thread | | | Date | Tue, 1 Apr 1997 11:42:34 +0200 (MET DST) | From | Pavel Machek <> | Subject | Re: uaccess.h reimplementation, patch, 2.1.30 (WP detection) |
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On Mon, 31 Mar 1997, Paul Gortmaker wrote:
> Okay, as soon as I saw Linus mention the broken WP support, I realized why > defining access_ok() to 1 was such a gain on i386. Since i386 requires the > check to be done in software due to the broken write protect issue, of > course access_ok() on i386 will be much more expensive (in both code size > and speed). On i486 or better, the speed difference is next to nothing as > seen below. There is still a size reduction win (20kB) though. Test is the > same 270 page LaTeX doc, only this time run on an i486-66 box (but with the > same NFS server). As before, I've discarded the timing data from the first > run after a reboot for obvious reasons.
Hey! The detection whether WP bit is working is BROKEN in 2.1.X. I thought that it is not important, but it looks like it is. (I tried to fix it but was unable to). On my AMD486DX2/80, 2.0.X's used to say that WP bit is working ok, with 2.1.X it no longer works. (BTW it would be nice to *always* print Checking WP bit, not only if test succeeds like it is done now).
Pavel
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