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/*
* Mach Operating System
* Copyright (c) 1991,1990 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie Mellon
* the rights to redistribute these changes.
*/
#include <vm/vm_fault.h>
#include <mach/kern_return.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/pmap.h>
#include <kern/macros.h>
/*
* Expansion of vm_fault for read fault in kernel mode.
* Must enter the mapping as writable, since the i386
* ignores write protection in kernel mode.
*/
kern_return_t
intel_read_fault(
vm_map_t map,
vm_offset_t vaddr)
{
vm_map_version_t version; /* Map version for
verification */
vm_object_t object; /* Top-level object */
vm_offset_t offset; /* Top-level offset */
vm_prot_t prot; /* Protection for mapping */
vm_page_t result_page; /* Result of vm_fault_page */
vm_page_t top_page; /* Placeholder page */
boolean_t wired; /* Is map region wired? */
kern_return_t result;
vm_page_t m;
RetryFault:
/*
* Find the backing store object and offset into it
* to begin search.
*/
result = vm_map_lookup(&map, vaddr, VM_PROT_READ, &version,
&object, &offset, &prot, &wired);
if (result != KERN_SUCCESS)
return (result);
/*
* Make a reference to this object to prevent its
* disposal while we are playing with it.
*/
assert(object->ref_count > 0);
object->ref_count++;
vm_object_paging_begin(object);
result = vm_fault_page(object, offset, VM_PROT_READ, FALSE, TRUE,
&prot, &result_page, &top_page,
FALSE, (void (*)()) 0);
if (result != VM_FAULT_SUCCESS) {
vm_object_deallocate(object);
switch (result) {
case VM_FAULT_RETRY:
goto RetryFault;
case VM_FAULT_INTERRUPTED:
return (KERN_SUCCESS);
case VM_FAULT_MEMORY_SHORTAGE:
VM_PAGE_WAIT((void (*)()) 0);
goto RetryFault;
case VM_FAULT_FICTITIOUS_SHORTAGE:
vm_page_more_fictitious();
goto RetryFault;
case VM_FAULT_MEMORY_ERROR:
return (KERN_MEMORY_ERROR);
}
}
m = result_page;
/*
* How to clean up the result of vm_fault_page. This
* happens whether the mapping is entered or not.
*/
#define UNLOCK_AND_DEALLOCATE \
MACRO_BEGIN \
vm_fault_cleanup(m->object, top_page); \
vm_object_deallocate(object); \
MACRO_END
/*
* What to do with the resulting page from vm_fault_page
* if it doesn't get entered into the physical map:
*/
#define RELEASE_PAGE(m) \
MACRO_BEGIN \
PAGE_WAKEUP_DONE(m); \
vm_page_lock_queues(); \
if (!m->active && !m->inactive) \
vm_page_activate(m); \
vm_page_unlock_queues(); \
MACRO_END
/*
* We must verify that the maps have not changed.
*/
vm_object_unlock(m->object);
while (!vm_map_verify(map, &version)) {
vm_object_t retry_object;
vm_offset_t retry_offset;
vm_prot_t retry_prot;
result = vm_map_lookup(&map, vaddr, VM_PROT_READ, &version,
&retry_object, &retry_offset, &retry_prot,
&wired);
if (result != KERN_SUCCESS) {
vm_object_lock(m->object);
RELEASE_PAGE(m);
UNLOCK_AND_DEALLOCATE;
return (result);
}
vm_object_unlock(retry_object);
if (retry_object != object || retry_offset != offset) {
vm_object_lock(m->object);
RELEASE_PAGE(m);
UNLOCK_AND_DEALLOCATE;
goto RetryFault;
}
}
/*
* Put the page in the physical map.
*/
PMAP_ENTER(map->pmap, vaddr, m, VM_PROT_READ|VM_PROT_WRITE, wired);
vm_object_lock(m->object);
vm_page_lock_queues();
if (!m->active && !m->inactive)
vm_page_activate(m);
m->reference = TRUE;
vm_page_unlock_queues();
vm_map_verify_done(map, &version);
PAGE_WAKEUP_DONE(m);
UNLOCK_AND_DEALLOCATE;
#undef UNLOCK_AND_DEALLOCATE
#undef RELEASE_PAGE
return (KERN_SUCCESS);
}
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