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Fix the root cause of the hack "disable optimizations for uvm_bio.c

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on 32 bit kernels".

gcc converts a division in the calculation of UBC_UMAP_ADDR macro
to multiplication (smul or combination of add/sll), and the
register of its result contains a garbage in upper 32 bits (the
upper 32 bits of smul/add/sll's result isn't zero cleared).

Then it passes to pseg_get{,_real} through pmap_extract without the
zero clear of upper 32 bits in the optimization case.  So the
result of pseg_get and pmap_extact sometimes gets screwed up.
This commit is contained in:
nakayama 2012-03-03 03:17:32 +00:00
parent 34ae6a8457
commit f8135722c9
1 changed files with 4 additions and 1 deletions
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5
sys/arch/sparc64/sparc64/locore.s
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@ -1,4 +1,4 @@
/* $NetBSD: locore.s,v 1.339 2012/02/19 21:06:30 rmind Exp $ */
/* $NetBSD: locore.s,v 1.340 2012/03/03 03:17:32 nakayama Exp $ */
/*
* Copyright (c) 2006-2010 Matthew R. Green
@ -5517,6 +5517,9 @@ ENTRY(pmap_copy_page_phys)
*/
ENTRY(pseg_get_real)
! flushw ! Make sure we don't have stack probs & lose hibits of %o
#ifndef _LP64
clruw %o1 ! Zero extend
#endif
ldx [%o0 + PM_PHYS], %o2 ! pmap->pm_segs
srax %o1, HOLESHIFT, %o3 ! Check for valid address