Author: andrew
Date: Tue Aug 23 15:48:27 2016
New Revision: 304685
URL: https://svnweb.freebsd.org/changeset/base/304685
Log:
Include the offset the virtual address is within an L1 or L2 block when
finding the vm_page_t in pmap_extract_and_hold. Previously it would return
the vm_page_t of the first page in a block. This would cause issues when,
for example, fsck reads from a device into the middle of a superpage. In
this case the read call would write to the start of the block, and not to
the buffer passed in.
Obtained from: ABT Systems Ltd
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Modified:
head/sys/arm64/arm64/pmap.c
Modified: head/sys/arm64/arm64/pmap.c
==============================================================================
--- head/sys/arm64/arm64/pmap.c Tue Aug 23 15:46:20 2016 (r304684)
+++ head/sys/arm64/arm64/pmap.c Tue Aug 23 15:48:27 2016 (r304685)
@@ -995,6 +995,7 @@ vm_page_t
pmap_extract_and_hold(pmap_t pmap, vm_offset_t va, vm_prot_t prot)
{
pt_entry_t *pte, tpte;
+ vm_offset_t off;
vm_paddr_t pa;
vm_page_t m;
int lvl;
@@ -1016,9 +1017,20 @@ retry:
tpte & ATTR_DESCR_MASK));
if (((tpte & ATTR_AP_RW_BIT) == ATTR_AP(ATTR_AP_RW)) ||
((prot & VM_PROT_WRITE) == 0)) {
+ switch(lvl) {
+ case 1:
+ off = va & L1_OFFSET;
+ break;
+ case 2:
+ off = va & L2_OFFSET;
+ break;
+ case 3:
+ default:
+ off = 0;
+ }
if (vm_page_pa_tryrelock(pmap, tpte & ~ATTR_MASK, &pa))
goto retry;
- m = PHYS_TO_VM_PAGE(tpte & ~ATTR_MASK);
+ m = PHYS_TO_VM_PAGE((tpte & ~ATTR_MASK) | off);
vm_page_hold(m);
}
}
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