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Ignore invalid page descriptors in ARM64 pmap_mincore

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Prevent the function from null-pointer-dereference when unexisting
    mapping is being processed.

Obtained from:         Semihalf
Sponsored by:          Cavium
Approved by:           cognet (mentor)
Reviewed by:           zbb, cognet
Differential revision: https://reviews.freebsd.org/D5228
This commit is contained in:
Wojciech Macek 2016-02-09 06:26:27 +00:00
parent 91ef8da010
commit c00a03a11d
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=295425
1 changed files with 12 additions and 0 deletions
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12
sys/arm64/arm64/pmap.c
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@ -3074,7 +3074,11 @@ pmap_mincore(pmap_t pmap, vm_offset_t addr, vm_paddr_t *locked_pa)
l1p = pmap_l1(pmap, addr);
if (l1p == NULL) /* No l1 */
goto done;
l1 = pmap_load(l1p);
if ((l1 & ATTR_DESCR_MASK) == L1_INVAL)
goto done;
if ((l1 & ATTR_DESCR_MASK) == L1_BLOCK) {
pa = (l1 & ~ATTR_MASK) | (addr & L1_OFFSET);
managed = (l1 & ATTR_SW_MANAGED) == ATTR_SW_MANAGED;
@ -3089,7 +3093,11 @@ pmap_mincore(pmap_t pmap, vm_offset_t addr, vm_paddr_t *locked_pa)
l2p = pmap_l1_to_l2(l1p, addr);
if (l2p == NULL) /* No l2 */
goto done;
l2 = pmap_load(l2p);
if ((l2 & ATTR_DESCR_MASK) == L2_INVAL)
goto done;
if ((l2 & ATTR_DESCR_MASK) == L2_BLOCK) {
pa = (l2 & ~ATTR_MASK) | (addr & L2_OFFSET);
managed = (l2 & ATTR_SW_MANAGED) == ATTR_SW_MANAGED;
@ -3104,7 +3112,11 @@ pmap_mincore(pmap_t pmap, vm_offset_t addr, vm_paddr_t *locked_pa)
l3p = pmap_l2_to_l3(l2p, addr);
if (l3p == NULL) /* No l3 */
goto done;
l3 = pmap_load(l2p);
if ((l3 & ATTR_DESCR_MASK) == L3_INVAL)
goto done;
if ((l3 & ATTR_DESCR_MASK) == L3_PAGE) {
pa = (l3 & ~ATTR_MASK) | (addr & L3_OFFSET);
managed = (l3 & ATTR_SW_MANAGED) == ATTR_SW_MANAGED;