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amd64 pmap_allocpte_nosleep(): stop testing tautological condition

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Enabled PTI for given pmap is equivalent to pm_ucr3 being valid is
equivalent to root userspace page table page pm_pmltopu being
allocated.

Reviewed by:	alc, markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D45966
This commit is contained in:
Konstantin Belousov 2024-07-13 07:07:18 +03:00
parent 616dd88a2e
commit 10a6ae0ddf
1 changed files with 5 additions and 4 deletions
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9
sys/amd64/amd64/pmap.c
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@ -4707,8 +4707,8 @@ pmap_allocpte_nosleep(pmap_t pmap, vm_pindex_t ptepindex, struct rwlock **lockp,
*pml5 = VM_PAGE_TO_PHYS(m) | PG_U | PG_RW | PG_V | PG_A | PG_M;
if (pmap->pm_pmltopu != NULL && pml5index < NUPML5E) {
if (pmap->pm_ucr3 != PMAP_NO_CR3)
*pml5 |= pg_nx;
MPASS(pmap->pm_ucr3 != PMAP_NO_CR3);
*pml5 |= pg_nx;
pml5u = &pmap->pm_pmltopu[pml5index];
*pml5u = VM_PAGE_TO_PHYS(m) | PG_U | PG_RW | PG_V |
@ -4728,6 +4728,8 @@ pmap_allocpte_nosleep(pmap_t pmap, vm_pindex_t ptepindex, struct rwlock **lockp,
if (!pmap_is_la57(pmap) && pmap->pm_pmltopu != NULL &&
pml4index < NUPML4E) {
MPASS(pmap->pm_ucr3 != PMAP_NO_CR3);
/*
* PTI: Make all user-space mappings in the
* kernel-mode page table no-execute so that
@ -4735,8 +4737,7 @@ pmap_allocpte_nosleep(pmap_t pmap, vm_pindex_t ptepindex, struct rwlock **lockp,
* the kernel-mode page table active on return
* to user space.
*/
if (pmap->pm_ucr3 != PMAP_NO_CR3)
*pml4 |= pg_nx;
*pml4 |= pg_nx;
pml4u = &pmap->pm_pmltopu[pml4index];
*pml4u = VM_PAGE_TO_PHYS(m) | PG_U | PG_RW | PG_V |