Date: Sat, 27 Sep 1997 01:23:44 -0400 (EDT) From: Wee Teck Ng <weeteck@eecs.umich.edu> To: freebsd-hackers@freebsd.org Subject: using vm_map_protect on Pentium PC Message-ID: <199709270523.BAA07578@singapore.eecs.umich.edu>
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hi all, we are heavily utilising VM protection (vm_map_prot) on 2.2-stable, and found that it doesn't work well on Pentium processor. specifically, when using vm_map_prot to change a page's protection from VM_PROT_READ to VM_PROT_ALL, only the vm map is updated. pmap_protect does not reset the pte to writeable (i.e. PG_RW). this will not work on pentium processor, since page level protection is enforced by the processor (against kernel access) when WP flag of CR0 is set. i've noticed that FreeBSD-current has fixed this problem. my questions are: 1) is there a 2.x release with a Pentium-compatible VM system? 2) how stable is 3.0 is for non SMP machines? thanks! wee teck
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