Author: nwhitehorn
Date: Wed Sep 8 16:58:06 2010
New Revision: 212322
URL: http://svn.freebsd.org/changeset/base/212322
Log:
Fix a typo in the original import of this code from NetBSD that caused the
wrong element of the VSID bitmap array to be examined after a collision,
leading to reallocation of in-use VSIDs under some circumstances, with
attendant memory corruption. Also add an assert to check for this kind of
problem in the future.
MFC after: 4 days
Modified:
head/sys/powerpc/aim/mmu_oea.c
head/sys/powerpc/aim/mmu_oea64.c
Modified: head/sys/powerpc/aim/mmu_oea.c
==============================================================================
--- head/sys/powerpc/aim/mmu_oea.c Wed Sep 8 16:34:08 2010
(r212321)
+++ head/sys/powerpc/aim/mmu_oea.c Wed Sep 8 16:58:06 2010
(r212322)
@@ -1618,7 +1618,7 @@ moea_pinit(mmu_t mmu, pmap_t pmap)
entropy = (moea_vsidcontext >> 20);
continue;
}
- i = ffs(~moea_vsid_bitmap[i]) - 1;
+ i = ffs(~moea_vsid_bitmap[n]) - 1;
mask = 1 << i;
hash &= 0xfffff & ~(VSID_NBPW - 1);
hash |= i;
Modified: head/sys/powerpc/aim/mmu_oea64.c
==============================================================================
--- head/sys/powerpc/aim/mmu_oea64.c Wed Sep 8 16:34:08 2010
(r212321)
+++ head/sys/powerpc/aim/mmu_oea64.c Wed Sep 8 16:58:06 2010
(r212322)
@@ -2080,11 +2080,13 @@ moea64_get_unique_vsid(void) {
entropy = (moea64_vsidcontext >> 20);
continue;
}
- i = ffs(~moea64_vsid_bitmap[i]) - 1;
+ i = ffs(~moea64_vsid_bitmap[n]) - 1;
mask = 1 << i;
hash &= VSID_HASHMASK & ~(VSID_NBPW - 1);
hash |= i;
}
+ KASSERT(!(moea64_vsid_bitmap[n] & mask),
+ ("Allocating in-use VSID %#x\n", hash));
moea64_vsid_bitmap[n] |= mask;
mtx_unlock(&moea64_slb_mutex);
return (hash);
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