Date: Wed, 22 Aug 2001 12:04:02 +0300 From: Peter Pentchev <roam@ringlet.net> To: Terry Lambert <tlambert2@mindspring.com> Cc: Peter Wemm <peter@wemm.org>, Mitsuru IWASAKI <iwasaki@jp.FreeBSD.org>, arch@FreeBSD.ORG, audit@FreeBSD.ORG, kumabu@t3.rim.or.jp Subject: Re: CFR: Timing to enable CR4.PGE bit Message-ID: <20010822120402.A8694@ringworld.oblivion.bg> In-Reply-To: <3B837418.2D5529E5@mindspring.com>; from tlambert2@mindspring.com on Wed, Aug 22, 2001 at 01:58:00AM -0700 References: <20010822082749.ED86038FD@overcee.netplex.com.au> <3B837418.2D5529E5@mindspring.com>
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On Wed, Aug 22, 2001 at 01:58:00AM -0700, Terry Lambert wrote: > Peter Wemm wrote: > > Page Global Enable (bit 7 of CR4). (Introduced in the P6 family > > processors.) Enables the global page feature when set; disables the > > global page feature when clear. [snip] In addition, the bit must not > > ^^^^^^^^^^^^^^^^ > > be enabled before paging is enabled via CR0.PG. Program correctness > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > may be affected by reversing this sequence, and processor performance > > will be impacted. > > ---- > > > > Currently, we enable CR4.PGE bit in create_pagetables, then enable > > CR0.PG in locore.s. This seems to violate Intel's note. > > Ah. It looked like an inverted patch to me... it moved the > code from line 725 or so in locore.s to line 375. > > I think moving this to _much_ later would not be a bad idea, > since the only effect will be that the PG_G bit is ignored > until it's actually enabled, right? > > FWIW: The message you quoted was from a cross-post from -audit > to -arch, which I guess originally came from -audit? So the > answer is "no, I didn't see the whole thread", and I only > became interested enough to read it when I saw the assemply > patch fly by on -arch. The message he quoted was the original message in the thread, addressed to *both* -arch and -audit. Here are the relevant headers: To: arch@FreeBSD.ORG Cc: audit@FreeBSD.ORG, kumabu@t3.rim.or.jp Subject: CFR: Timing to enable CR4.PGE bit Date: Thu, 09 Aug 2001 03:58:01 +0900 From: Mitsuru IWASAKI <iwasaki@jp.FreeBSD.org> G'luck, Peter -- No language can express every thought unambiguously, least of all this one. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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