diff options
Diffstat (limited to 'i386/intel/read_fault.c')
| -rw-r--r-- | i386/intel/read_fault.c | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/i386/intel/read_fault.c b/i386/intel/read_fault.c new file mode 100644 index 00000000..d0c03e83 --- /dev/null +++ b/i386/intel/read_fault.c @@ -0,0 +1,178 @@ +/* + * 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/macro_help.h> + +/* + * Expansion of vm_fault for read fault in kernel mode. + * Must enter the mapping as writable, since the i386 + * (and i860 in i386 compatability mode) ignores write + * protection in kernel mode. + */ +kern_return_t +intel_read_fault(map, vaddr) + 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? */ + boolean_t su; + kern_return_t result; + register 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, &su); + 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, &su); + 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); +} |