2 # Copyright (c) 2005 Peter Grehan
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6 # modification, are permitted provided that the following conditions
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29 #include <sys/param.h>
31 #include <sys/mutex.h>
32 #include <sys/systm.h>
35 #include <vm/vm_page.h>
37 #include <machine/mmuvar.h>
40 * @defgroup MMU mmu - KObj methods for PowerPC MMU implementations
41 * @brief A set of methods required by all MMU implementations. These
42 * are basically direct call-thru's from the pmap machine-dependent
44 * Thanks to Bruce M Simpson's pmap man pages for routine descriptions.
51 # Default implementations of some methods
54 static void mmu_null_copy(mmu_t mmu, pmap_t dst_pmap, pmap_t src_pmap,
55 vm_offset_t dst_addr, vm_size_t len, vm_offset_t src_addr)
60 static void mmu_null_growkernel(mmu_t mmu, vm_offset_t addr)
65 static void mmu_null_init(mmu_t mmu)
70 static boolean_t mmu_null_is_prefaultable(mmu_t mmu, pmap_t pmap,
76 static void mmu_null_object_init_pt(mmu_t mmu, pmap_t pmap,
77 vm_offset_t addr, vm_object_t object, vm_pindex_t index,
83 static void mmu_null_page_init(mmu_t mmu, vm_page_t m)
88 static void mmu_null_remove_pages(mmu_t mmu, pmap_t pmap)
93 static int mmu_null_mincore(mmu_t mmu, pmap_t pmap, vm_offset_t addr)
98 static void mmu_null_deactivate(struct thread *td)
103 static vm_offset_t mmu_null_addr_hint(mmu_t mmu, vm_object_t object,
104 vm_offset_t va, vm_size_t size)
112 * @brief Change the wiring attribute for the page in the given physical
113 * map and virtual address.
115 * @param _pmap physical map of page
116 * @param _va page virtual address
117 * @param _wired TRUE to increment wired count, FALSE to decrement
119 METHOD void change_wiring {
128 * @brief Clear the 'modified' bit on the given physical page
130 * @param _pg physical page
132 METHOD void clear_modify {
139 * @brief Clear the 'referenced' bit on the given physical page
141 * @param _pg physical page
143 METHOD void clear_reference {
150 * @brief Clear the write and modified bits in each of the given
151 * physical page's mappings
153 * @param _pg physical page
155 METHOD void remove_write {
162 * @brief Copy the address range given by the source physical map, virtual
163 * address and length to the destination physical map and virtual address.
164 * This routine is optional (xxx default null implementation ?)
166 * @param _dst_pmap destination physical map
167 * @param _src_pmap source physical map
168 * @param _dst_addr destination virtual address
169 * @param _len size of range
170 * @param _src_addr source virtual address
176 vm_offset_t _dst_addr;
178 vm_offset_t _src_addr;
179 } DEFAULT mmu_null_copy;
183 * @brief Copy the source physical page to the destination physical page
185 * @param _src source physical page
186 * @param _dst destination physical page
188 METHOD void copy_page {
196 * @brief Create a mapping between a virtual/physical address pair in the
197 * passed physical map with the specified protection and wiring
199 * @param _pmap physical map
200 * @param _va mapping virtual address
201 * @param _p mapping physical page
202 * @param _prot mapping page protection
203 * @param _wired TRUE if page will be wired
216 * @brief Maps a sequence of resident pages belonging to the same object.
218 * @param _pmap physical map
219 * @param _start virtual range start
220 * @param _end virtual range end
221 * @param _m_start physical page mapped at start
222 * @param _prot mapping page protection
224 METHOD void enter_object {
235 * @brief A faster entry point for page mapping where it is possible
236 * to short-circuit some of the tests in pmap_enter.
238 * @param _pmap physical map (and also currently active pmap)
239 * @param _va mapping virtual address
240 * @param _pg mapping physical page
241 * @param _prot new page protection - used to see if page is exec.
243 METHOD void enter_quick {
253 * @brief Reverse map the given virtual address, returning the physical
254 * page associated with the address if a mapping exists.
256 * @param _pmap physical map
257 * @param _va mapping virtual address
259 * @retval 0 No mapping found
260 * @retval addr The mapping physical address
262 METHOD vm_paddr_t extract {
270 * @brief Reverse map the given virtual address, returning the
271 * physical page if found. The page must be held (by calling
272 * vm_page_hold) if the page protection matches the given protection
274 * @param _pmap physical map
275 * @param _va mapping virtual address
276 * @param _prot protection used to determine if physical page
279 * @retval NULL No mapping found
280 * @retval page Pointer to physical page. Held if protections match
282 METHOD vm_page_t extract_and_hold {
291 * @brief Increase kernel virtual address space to the given virtual address.
292 * Not really required for PowerPC, so optional unless the MMU implementation
295 * @param _va new upper limit for kernel virtual address space
297 METHOD void growkernel {
300 } DEFAULT mmu_null_growkernel;
304 * @brief Called from vm_mem_init. Zone allocation is available at
305 * this stage so a convenient time to create zones. This routine is
306 * for MMU-implementation convenience and is optional.
310 } DEFAULT mmu_null_init;
314 * @brief Return if the page has been marked by MMU hardware to have been
317 * @param _pg physical page to test
319 * @retval boolean TRUE if page has been modified
321 METHOD boolean_t is_modified {
328 * @brief Return whether the specified virtual address is a candidate to be
329 * prefaulted in. This routine is optional.
331 * @param _pmap physical map
332 * @param _va virtual address to test
334 * @retval boolean TRUE if the address is a candidate.
336 METHOD boolean_t is_prefaultable {
340 } DEFAULT mmu_null_is_prefaultable;
344 * @brief Return a count of referenced bits for a page, clearing those bits.
345 * Not all referenced bits need to be cleared, but it is necessary that 0
346 * only be returned when there are none set.
348 * @params _m physical page
350 * @retval int count of referenced bits
352 METHOD boolean_t ts_referenced {
359 * @brief Map the requested physical address range into kernel virtual
360 * address space. The value in _virt is taken as a hint. The virtual
361 * address of the range is returned, or NULL if the mapping could not
362 * be created. The range can be direct-mapped if that is supported.
364 * @param *_virt Hint for start virtual address, and also return
366 * @param _start physical address range start
367 * @param _end physical address range end
368 * @param _prot protection of range (currently ignored)
370 * @retval NULL could not map the area
371 * @retval addr, *_virt mapping start virtual address
373 METHOD vm_offset_t map {
383 * @brief Used to create a contiguous set of read-only mappings for a
384 * given object to try and eliminate a cascade of on-demand faults as
385 * the object is accessed sequentially. This routine is optional.
387 * @param _pmap physical map
388 * @param _addr mapping start virtual address
389 * @param _object device-backed V.M. object to be mapped
390 * @param _pindex page-index within object of mapping start
391 * @param _size size in bytes of mapping
393 METHOD void object_init_pt {
400 } DEFAULT mmu_null_object_init_pt;
404 * @brief Used to determine if the specified page has a mapping for the
405 * given physical map, by scanning the list of reverse-mappings from the
406 * page. The list is scanned to a maximum of 16 entries.
408 * @param _pmap physical map
409 * @param _pg physical page
411 * @retval bool TRUE if the physical map was found in the first 16
412 * reverse-map list entries off the physical page.
414 METHOD boolean_t page_exists_quick {
422 * @brief Initialise the machine-dependent section of the physical page
423 * data structure. This routine is optional.
425 * @param _pg physical page
427 METHOD void page_init {
430 } DEFAULT mmu_null_page_init;
434 * @brief Initialise a physical map data structure
436 * @param _pmap physical map
445 * @brief Initialise the physical map for process 0, the initial process
447 * XXX default to pinit ?
449 * @param _pmap physical map
458 * @brief Set the protection for physical pages in the given virtual address
459 * range to the given value.
461 * @param _pmap physical map
462 * @param _start virtual range start
463 * @param _end virtual range end
464 * @param _prot new page protection
466 METHOD void protect {
476 * @brief Create a mapping in kernel virtual address space for the given array
477 * of wired physical pages.
479 * @param _start mapping virtual address start
480 * @param *_m array of physical page pointers
481 * @param _count array elements
492 * @brief Remove the temporary mappings created by qenter.
494 * @param _start mapping virtual address start
495 * @param _count number of pages in mapping
497 METHOD void qremove {
505 * @brief Release per-pmap resources, e.g. mutexes, allocated memory etc. There
506 * should be no existing mappings for the physical map at this point
508 * @param _pmap physical map
510 METHOD void release {
517 * @brief Remove all mappings in the given physical map for the start/end
518 * virtual address range. The range will be page-aligned.
520 * @param _pmap physical map
521 * @param _start mapping virtual address start
522 * @param _end mapping virtual address end
533 * @brief Traverse the reverse-map list off the given physical page and
534 * remove all mappings. Clear the PG_WRITEABLE attribute from the page.
536 * @param _pg physical page
538 METHOD void remove_all {
545 * @brief Remove all mappings in the given start/end virtual address range
546 * for the given physical map. Similar to the remove method, but it used
547 * when tearing down all mappings in an address space. This method is
548 * optional, since pmap_remove will be called for each valid vm_map in
549 * the address space later.
551 * @param _pmap physical map
552 * @param _start mapping virtual address start
553 * @param _end mapping virtual address end
555 METHOD void remove_pages {
558 } DEFAULT mmu_null_remove_pages;
562 * @brief Zero a physical page. It is not assumed that the page is mapped,
563 * so a temporary (or direct) mapping may need to be used.
565 * @param _pg physical page
567 METHOD void zero_page {
574 * @brief Zero a portion of a physical page, starting at a given offset and
575 * for a given size (multiples of 512 bytes for 4k pages).
577 * @param _pg physical page
578 * @param _off byte offset from start of page
579 * @param _size size of area to zero
581 METHOD void zero_page_area {
590 * @brief Called from the idle loop to zero pages. XXX I think locking
591 * constraints might be different here compared to zero_page.
593 * @param _pg physical page
595 METHOD void zero_page_idle {
602 * @brief Extract mincore(2) information from a mapping. This routine is
603 * optional and is an optimisation: the mincore code will call is_modified
604 * and ts_referenced if no result is returned.
606 * @param _pmap physical map
607 * @param _addr page virtual address
609 * @retval 0 no result
610 * @retval non-zero mincore(2) flag values
616 } DEFAULT mmu_null_mincore;
620 * @brief Perform any operations required to allow a physical map to be used
621 * before it's address space is accessed.
623 * @param _td thread associated with physical map
625 METHOD void activate {
631 * @brief Perform any operations required to deactivate a physical map,
632 * for instance as it is context-switched out.
634 * @param _td thread associated with physical map
636 METHOD void deactivate {
639 } DEFAULT mmu_null_deactivate;
642 * @brief Return a hint for the best virtual address to map a tentative
643 * virtual address range in a given VM object. The default is to just
644 * return the given tentative start address.
646 * @param _obj VM backing object
647 * @param _addr initial guess at virtual address
648 * @param _size size of virtual address range
650 METHOD vm_offset_t addr_hint {
655 } DEFAULT mmu_null_addr_hint;
661 * INTERNAL INTERFACES
665 * @brief Bootstrap the VM system. At the completion of this routine, the
666 * kernel will be running in it's own address space with full control over
669 * @param _start start of reserved memory (obsolete ???)
670 * @param _end end of reserved memory (obsolete ???)
671 * XXX I think the intent of these was to allow
672 * the memory used by kernel text+data+bss and
673 * loader variables/load-time kld's to be carved out
674 * of available physical mem.
677 METHOD void bootstrap {
685 * @brief Create a kernel mapping for a given physical address range.
686 * Called by bus code on behalf of device drivers. The mapping does not
687 * have to be a virtual address: it can be a direct-mapped physical address
688 * if that is supported by the MMU.
690 * @param _pa start physical address
691 * @param _size size in bytes of mapping
693 * @retval addr address of mapping.
695 METHOD void * mapdev {
703 * @brief Remove the mapping created by mapdev. Called when a driver
706 * @param _va Mapping address returned from mapdev
707 * @param _size size in bytes of mapping
709 METHOD void unmapdev {
717 * @brief Reverse-map a kernel virtual address
719 * @param _va kernel virtual address to reverse-map
721 * @retval pa physical address corresponding to mapping
723 METHOD vm_offset_t kextract {
730 * @brief Map a wired page into kernel virtual address space
732 * @param _va mapping virtual address
733 * @param _pa mapping physical address
743 * @brief Determine if the given physical address range has been direct-mapped.
745 * @param _pa physical address start
746 * @param _size physical address range size
748 * @retval bool TRUE if the range is direct-mapped.
750 METHOD boolean_t dev_direct_mapped {
758 * @brief Evaluate if a physical page has an executable mapping
760 * @param _pg physical page
762 * @retval bool TRUE if a physical mapping exists for the given page.
764 METHOD boolean_t page_executable {