From 5bd0149714c1ee467cda3558bf318aca0bb86898 Mon Sep 17 00:00:00 2001 From: Conrad Meyer Date: Wed, 14 Feb 2018 23:35:47 +0000 Subject: [PATCH] x86 pmap: Make memory mapped via pmap_qenter() non-executable The idea is, the pmap_qenter() API is now defined to not produce executable mappings. If you need executable mappings, use another API. Add pg_nx flag in pmap_qenter on x86 to make kernel pages non-executable. Other architectures that support execute-specific permissons on page table entries should subsequently be updated to match. Submitted by: Darrick Lew Reviewed by: markj Discussed with: alc, jhb, kib Sponsored by: Dell EMC Isilon Differential Revision: https://reviews.freebsd.org/D14062 --- sys/amd64/amd64/pmap.c | 2 +- sys/i386/i386/pmap.c | 4 ++++ 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c index 0d13978f918..8c0b372eb4d 100644 --- a/sys/amd64/amd64/pmap.c +++ b/sys/amd64/amd64/pmap.c @@ -2338,7 +2338,7 @@ pmap_qenter(vm_offset_t sva, vm_page_t *ma, int count) pa = VM_PAGE_TO_PHYS(m) | cache_bits; if ((*pte & (PG_FRAME | X86_PG_PTE_CACHE)) != pa) { oldpte |= *pte; - pte_store(pte, pa | pg_g | X86_PG_RW | X86_PG_V); + pte_store(pte, pa | pg_g | pg_nx | X86_PG_RW | X86_PG_V); } pte++; } diff --git a/sys/i386/i386/pmap.c b/sys/i386/i386/pmap.c index 092c2f9909c..c0895cabcc2 100644 --- a/sys/i386/i386/pmap.c +++ b/sys/i386/i386/pmap.c @@ -1677,7 +1677,11 @@ pmap_qenter(vm_offset_t sva, vm_page_t *ma, int count) pa = VM_PAGE_TO_PHYS(m) | pmap_cache_bits(m->md.pat_mode, 0); if ((*pte & (PG_FRAME | PG_PTE_CACHE)) != pa) { oldpte |= *pte; +#if defined(PAE) || defined(PAE_TABLES) + pte_store(pte, pa | pgeflag | pg_nx | PG_RW | PG_V); +#else pte_store(pte, pa | pgeflag | PG_RW | PG_V); +#endif } pte++; }