Date: Tue, 07 Oct 2003 21:23:23 -0600 From: Scott Long <scottl@freebsd.org> To: David Rhodus <drhodus@catpa.com> Cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/i386/i386 pmap.c Message-ID: <3F83832B.407@freebsd.org> In-Reply-To: <4906E41E-F938-11D7-B905-000A959B213E@catpa.com> References: <4906E41E-F938-11D7-B905-000A959B213E@catpa.com>
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David Rhodus wrote: > > On Tuesday, October 7, 2003, at 08:53 AM, Jacques A. Vidrine wrote: > >> On Tue, Oct 07, 2003 at 05:34:37AM -0700, Jacques A. Vidrine wrote: >> >>> nectar 2003/10/07 05:34:37 PDT >>> >>> FreeBSD src repository >>> >>> Modified files: (Branch: RELENG_4) >>> sys/i386/i386 pmap.c >>> Log: >>> Disable PSE at boot time for Pentium 4 processors. On many such CPUs, >>> data corruption will result otherwise. It seems that the bug is >>> aggravated by recent work related to PAE. >>> >>> This change was originally based on rev 1.386, but now the test for >>> CPU type is correct and the display of the warning is postponed until >>> we have initialized the kernel message buffer (e.g. for dmesg). >>> >>> peter@ believes that only certain revisions of the Pentium 4 processor >>> are affected. However, we are unsure which so we choose to be safe by >>> disabling PSE on all Pentium 4s. >>> >>> The test can be disabled entirely with NO_PSE_HACK. >>> >>> Approved by: re >>> >>> Revision Changes Path >>> 1.250.2.22 +34 -0 src/sys/i386/i386/pmap.c >> >> >> The symptoms from this bug that I experienced on an ``Intel(R) >> Celeron(R) CPU 2.00GHz'' system were SIGBUS and SIGSEGV during `make >> buildworld'. > > > Interesting, I was just typing a message to ask if we needed to look at > applying bmilekic's work to RELENG_4. Is that being looked at as a > more elegant method rather than leaving PSE turned off. > > -DR > > It might indeed be interesting to backport Bosko's work to 4.x. However, we are too close to the 4.9 release to do it now. Jacques' work is recognised as a band-aid for now. Scott
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