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x86 pmap: Make memory mapped via pmap_qenter() non-executable

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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 <darrick.freebsd AT gmail.com>
Reviewed by:	markj
Discussed with:	alc, jhb, kib
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D14062
This commit is contained in:
Conrad Meyer 2018-02-14 23:35:47 +00:00
parent 8be8c75688
commit 5bd0149714
2 changed files with 5 additions and 1 deletions
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2
sys/amd64/amd64/pmap.c
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@ -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++;
}

4
sys/i386/i386/pmap.c
View file

@ -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++;
}