Date: Mon, 13 Apr 2015 11:24:09 -0400 From: Benjamin Kaduk <bjkfbsd@gmail.com> To: Konstantin Belousov <kib@freebsd.org> Cc: "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org> Subject: Re: svn commit: r281495 - in head/sys: conf i386/i386 i386/include x86/acpica Message-ID: <CAJ5_RoBb%2BpPLW=-CPVdyCH%2BDnqAJyOA8BK5sei4zwKPz5BH0eg@mail.gmail.com> In-Reply-To: <201504131522.t3DFMkiE050257@svn.freebsd.org> References: <201504131522.t3DFMkiE050257@svn.freebsd.org>
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On Mon, Apr 13, 2015 at 11:22 AM, Konstantin Belousov <kib@freebsd.org> wrote: > Author: kib > Date: Mon Apr 13 15:22:45 2015 > New Revision: 281495 > URL: https://svnweb.freebsd.org/changeset/base/281495 > > Log: > Add config option PAE_TABLES for the i386 kernel. It switches pmap to > use PAE format for the page tables, but does not incur other > consequences of the full PAE config. In particular, vm_paddr_t and > bus_addr_t are left 32bit, and max supported memory is still limited > by 4GB. > > The option allows to have nx permissions for memory mappings on i386 > kernel, while keeping the usual i386 KBI and avoiding the kernel data > sizing problems typical for the PAE config. > > Intel documented that the PAE format for page tables is available > starting with the Pentium Pro, but it is possible that the plain > Pentium CPUs have the required support (Appendix H). The goal is to > enable the option and non-exec mappings on i386 for the GENERIC > kernel. Anybody wanting a useful system on 486, have to reconfigure > the modern i386 kernel anyway. > > Discussed with: alc, jhb > Sponsored by: The FreeBSD Foundation > MFC after: 2 weeks > relnotes: yes? -Ben
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