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In uvm_pagermapin(), pass VM_PROT_READ|VM_PROT_WRITE as access_type, to

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ensure we don't take mod/ref emulation faults in an interrupt context
(e.g. during the i/o operation).  This is safe because:
	- For a pageout operation, the page is already known to be
	  modified, and the pagedaemon will pmap_clear_modify() after
	  the pageout has completed.
	- For a pagein operation, pagers must already pmap_clear_modify()
	  after the pagein operation is complete, because the i/o may have
	  been done with e.g. programmed i/o.
XXX It would be nice to know the i/o direction so that we can call
XXX pmap_enter() with only the protection and access_type necessary.
This commit is contained in:
thorpej 1999-05-26 06:42:57 +00:00
parent 5dd4815be9
commit 00a1f75cf6
1 changed files with 11 additions and 2 deletions
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13
sys/uvm/uvm_pager.c
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@ -1,4 +1,4 @@
/* $NetBSD: uvm_pager.c,v 1.18 1999/05/24 23:36:23 thorpej Exp $ */
/* $NetBSD: uvm_pager.c,v 1.19 1999/05/26 06:42:57 thorpej Exp $ */
/*
*
@ -116,6 +116,9 @@ uvm_pager_init()
*
* we basically just map in a blank map entry to reserve the space in the
* map and then use pmap_enter() to put the mappings in by hand.
*
* XXX It would be nice to know the direction of the I/O, so that we can
* XXX map only what is necessary.
*/
vaddr_t
@ -172,8 +175,14 @@ ReStart:
panic("uvm_pagermapin: page not busy");
#endif
/*
* XXX VM_PROT_DEFAULT includes VM_PROT_EXEC; is that
* XXX really necessary? It could lead to unnecessary
* XXX instruction cache flushes.
*/
pmap_enter(vm_map_pmap(pager_map), cva, VM_PAGE_TO_PHYS(pp),
VM_PROT_DEFAULT, TRUE, 0);
VM_PROT_DEFAULT, TRUE,
VM_PROT_READ | VM_PROT_WRITE);
}
UVMHIST_LOG(maphist, "<- done (KVA=0x%x)", kva,0,0,0);