Date: Fri, 20 Apr 2018 15:35:58 +0000 (UTC) From: "Jonathan T. Looney" <jtl@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r332827 - stable/11/sys/amd64/amd64 Message-ID: <201804201535.w3KFZwiK091916@repo.freebsd.org>
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Author: jtl Date: Fri Apr 20 15:35:58 2018 New Revision: 332827 URL: https://svnweb.freebsd.org/changeset/base/332827 Log: MFC r330511: We shouldn't need to execute code in the recursive page table mappings; therefore, it should be safe to set the NX bit on the PML4E for the recursive page table mappings. According to the Intel docs, the effect of the NX bit should propogate to any page reached through a PML4E which has the NX bit set. Sponsored by: Netflix, Inc. Modified: stable/11/sys/amd64/amd64/pmap.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/amd64/amd64/pmap.c ============================================================================== --- stable/11/sys/amd64/amd64/pmap.c Fri Apr 20 15:28:58 2018 (r332826) +++ stable/11/sys/amd64/amd64/pmap.c Fri Apr 20 15:35:58 2018 (r332827) @@ -984,7 +984,7 @@ create_pagetables(vm_paddr_t *firstaddr) /* And recursively map PML4 to itself in order to get PTmap */ p4_p = (pml4_entry_t *)KPML4phys; p4_p[PML4PML4I] = KPML4phys; - p4_p[PML4PML4I] |= X86_PG_RW | X86_PG_V | PG_U; + p4_p[PML4PML4I] |= X86_PG_RW | X86_PG_V | PG_U | pg_nx; /* Connect the Direct Map slot(s) up to the PML4. */ for (i = 0; i < ndmpdpphys; i++) {
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