xref: /openbmc/linux/arch/mips/include/asm/pgtable.h (revision bbde9fc1824aab58bc78c084163007dd6c03fe5b)
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (C) 2003 Ralf Baechle
7  */
8 #ifndef _ASM_PGTABLE_H
9 #define _ASM_PGTABLE_H
10 
11 #include <linux/mm_types.h>
12 #include <linux/mmzone.h>
13 #ifdef CONFIG_32BIT
14 #include <asm/pgtable-32.h>
15 #endif
16 #ifdef CONFIG_64BIT
17 #include <asm/pgtable-64.h>
18 #endif
19 
20 #include <asm/io.h>
21 #include <asm/pgtable-bits.h>
22 
23 struct mm_struct;
24 struct vm_area_struct;
25 
26 #define PAGE_NONE	__pgprot(_PAGE_PRESENT | _CACHE_CACHABLE_NONCOHERENT)
27 #define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_WRITE | _PAGE_READ | \
28 				 _page_cachable_default)
29 #define PAGE_COPY	__pgprot(_PAGE_PRESENT | _PAGE_READ | _PAGE_NO_EXEC | \
30 				 _page_cachable_default)
31 #define PAGE_READONLY	__pgprot(_PAGE_PRESENT | _PAGE_READ | \
32 				 _page_cachable_default)
33 #define PAGE_KERNEL	__pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
34 				 _PAGE_GLOBAL | _page_cachable_default)
35 #define PAGE_KERNEL_NC	__pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \
36 				 _PAGE_GLOBAL | _CACHE_CACHABLE_NONCOHERENT)
37 #define PAGE_USERIO	__pgprot(_PAGE_PRESENT | _PAGE_READ | _PAGE_WRITE | \
38 				 _page_cachable_default)
39 #define PAGE_KERNEL_UNCACHED __pgprot(_PAGE_PRESENT | __READABLE | \
40 			__WRITEABLE | _PAGE_GLOBAL | _CACHE_UNCACHED)
41 
42 /*
43  * If _PAGE_NO_EXEC is not defined, we can't do page protection for
44  * execute, and consider it to be the same as read. Also, write
45  * permissions imply read permissions. This is the closest we can get
46  * by reasonable means..
47  */
48 
49 /*
50  * Dummy values to fill the table in mmap.c
51  * The real values will be generated at runtime
52  */
53 #define __P000 __pgprot(0)
54 #define __P001 __pgprot(0)
55 #define __P010 __pgprot(0)
56 #define __P011 __pgprot(0)
57 #define __P100 __pgprot(0)
58 #define __P101 __pgprot(0)
59 #define __P110 __pgprot(0)
60 #define __P111 __pgprot(0)
61 
62 #define __S000 __pgprot(0)
63 #define __S001 __pgprot(0)
64 #define __S010 __pgprot(0)
65 #define __S011 __pgprot(0)
66 #define __S100 __pgprot(0)
67 #define __S101 __pgprot(0)
68 #define __S110 __pgprot(0)
69 #define __S111 __pgprot(0)
70 
71 extern unsigned long _page_cachable_default;
72 
73 /*
74  * ZERO_PAGE is a global shared page that is always zero; used
75  * for zero-mapped memory areas etc..
76  */
77 
78 extern unsigned long empty_zero_page;
79 extern unsigned long zero_page_mask;
80 
81 #define ZERO_PAGE(vaddr) \
82 	(virt_to_page((void *)(empty_zero_page + (((unsigned long)(vaddr)) & zero_page_mask))))
83 #define __HAVE_COLOR_ZERO_PAGE
84 
85 extern void paging_init(void);
86 
87 /*
88  * Conversion functions: convert a page and protection to a page entry,
89  * and a page entry and page directory to the page they refer to.
90  */
91 #define pmd_phys(pmd)		virt_to_phys((void *)pmd_val(pmd))
92 
93 #define __pmd_page(pmd)		(pfn_to_page(pmd_phys(pmd) >> PAGE_SHIFT))
94 #ifndef CONFIG_TRANSPARENT_HUGEPAGE
95 #define pmd_page(pmd)		__pmd_page(pmd)
96 #endif /* CONFIG_TRANSPARENT_HUGEPAGE  */
97 
98 #define pmd_page_vaddr(pmd)	pmd_val(pmd)
99 
100 #define htw_stop()							\
101 do {									\
102 	unsigned long flags;						\
103 									\
104 	if (cpu_has_htw) {						\
105 		local_irq_save(flags);					\
106 		if(!raw_current_cpu_data.htw_seq++) {			\
107 			write_c0_pwctl(read_c0_pwctl() &		\
108 				       ~(1 << MIPS_PWCTL_PWEN_SHIFT));	\
109 			back_to_back_c0_hazard();			\
110 		}							\
111 		local_irq_restore(flags);				\
112 	}								\
113 } while(0)
114 
115 #define htw_start()							\
116 do {									\
117 	unsigned long flags;						\
118 									\
119 	if (cpu_has_htw) {						\
120 		local_irq_save(flags);					\
121 		if (!--raw_current_cpu_data.htw_seq) {			\
122 			write_c0_pwctl(read_c0_pwctl() |		\
123 				       (1 << MIPS_PWCTL_PWEN_SHIFT));	\
124 			back_to_back_c0_hazard();			\
125 		}							\
126 		local_irq_restore(flags);				\
127 	}								\
128 } while(0)
129 
130 #if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
131 
132 #define pte_none(pte)		(!(((pte).pte_high) & ~_PAGE_GLOBAL))
133 #define pte_present(pte)	((pte).pte_low & _PAGE_PRESENT)
134 
135 static inline void set_pte(pte_t *ptep, pte_t pte)
136 {
137 	ptep->pte_high = pte.pte_high;
138 	smp_wmb();
139 	ptep->pte_low = pte.pte_low;
140 
141 	if (pte.pte_high & _PAGE_GLOBAL) {
142 		pte_t *buddy = ptep_buddy(ptep);
143 		/*
144 		 * Make sure the buddy is global too (if it's !none,
145 		 * it better already be global)
146 		 */
147 		if (pte_none(*buddy))
148 			buddy->pte_high |= _PAGE_GLOBAL;
149 	}
150 }
151 #define set_pte_at(mm, addr, ptep, pteval) set_pte(ptep, pteval)
152 
153 static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
154 {
155 	pte_t null = __pte(0);
156 
157 	htw_stop();
158 	/* Preserve global status for the pair */
159 	if (ptep_buddy(ptep)->pte_high & _PAGE_GLOBAL)
160 		null.pte_high = _PAGE_GLOBAL;
161 
162 	set_pte_at(mm, addr, ptep, null);
163 	htw_start();
164 }
165 #else
166 
167 #define pte_none(pte)		(!(pte_val(pte) & ~_PAGE_GLOBAL))
168 #define pte_present(pte)	(pte_val(pte) & _PAGE_PRESENT)
169 
170 /*
171  * Certain architectures need to do special things when pte's
172  * within a page table are directly modified.  Thus, the following
173  * hook is made available.
174  */
175 static inline void set_pte(pte_t *ptep, pte_t pteval)
176 {
177 	*ptep = pteval;
178 #if !defined(CONFIG_CPU_R3000) && !defined(CONFIG_CPU_TX39XX)
179 	if (pte_val(pteval) & _PAGE_GLOBAL) {
180 		pte_t *buddy = ptep_buddy(ptep);
181 		/*
182 		 * Make sure the buddy is global too (if it's !none,
183 		 * it better already be global)
184 		 */
185 		if (pte_none(*buddy))
186 			pte_val(*buddy) = pte_val(*buddy) | _PAGE_GLOBAL;
187 	}
188 #endif
189 }
190 #define set_pte_at(mm, addr, ptep, pteval) set_pte(ptep, pteval)
191 
192 static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
193 {
194 	htw_stop();
195 #if !defined(CONFIG_CPU_R3000) && !defined(CONFIG_CPU_TX39XX)
196 	/* Preserve global status for the pair */
197 	if (pte_val(*ptep_buddy(ptep)) & _PAGE_GLOBAL)
198 		set_pte_at(mm, addr, ptep, __pte(_PAGE_GLOBAL));
199 	else
200 #endif
201 		set_pte_at(mm, addr, ptep, __pte(0));
202 	htw_start();
203 }
204 #endif
205 
206 /*
207  * (pmds are folded into puds so this doesn't get actually called,
208  * but the define is needed for a generic inline function.)
209  */
210 #define set_pmd(pmdptr, pmdval) do { *(pmdptr) = (pmdval); } while(0)
211 
212 #ifndef __PAGETABLE_PMD_FOLDED
213 /*
214  * (puds are folded into pgds so this doesn't get actually called,
215  * but the define is needed for a generic inline function.)
216  */
217 #define set_pud(pudptr, pudval) do { *(pudptr) = (pudval); } while(0)
218 #endif
219 
220 #define PGD_T_LOG2	(__builtin_ffs(sizeof(pgd_t)) - 1)
221 #define PMD_T_LOG2	(__builtin_ffs(sizeof(pmd_t)) - 1)
222 #define PTE_T_LOG2	(__builtin_ffs(sizeof(pte_t)) - 1)
223 
224 /*
225  * We used to declare this array with size but gcc 3.3 and older are not able
226  * to find that this expression is a constant, so the size is dropped.
227  */
228 extern pgd_t swapper_pg_dir[];
229 
230 /*
231  * The following only work if pte_present() is true.
232  * Undefined behaviour if not..
233  */
234 #if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
235 static inline int pte_write(pte_t pte)	{ return pte.pte_low & _PAGE_WRITE; }
236 static inline int pte_dirty(pte_t pte)	{ return pte.pte_low & _PAGE_MODIFIED; }
237 static inline int pte_young(pte_t pte)	{ return pte.pte_low & _PAGE_ACCESSED; }
238 
239 static inline pte_t pte_wrprotect(pte_t pte)
240 {
241 	pte.pte_low  &= ~_PAGE_WRITE;
242 	pte.pte_high &= ~_PAGE_SILENT_WRITE;
243 	return pte;
244 }
245 
246 static inline pte_t pte_mkclean(pte_t pte)
247 {
248 	pte.pte_low  &= ~_PAGE_MODIFIED;
249 	pte.pte_high &= ~_PAGE_SILENT_WRITE;
250 	return pte;
251 }
252 
253 static inline pte_t pte_mkold(pte_t pte)
254 {
255 	pte.pte_low  &= ~_PAGE_ACCESSED;
256 	pte.pte_high &= ~_PAGE_SILENT_READ;
257 	return pte;
258 }
259 
260 static inline pte_t pte_mkwrite(pte_t pte)
261 {
262 	pte.pte_low |= _PAGE_WRITE;
263 	if (pte.pte_low & _PAGE_MODIFIED)
264 		pte.pte_high |= _PAGE_SILENT_WRITE;
265 	return pte;
266 }
267 
268 static inline pte_t pte_mkdirty(pte_t pte)
269 {
270 	pte.pte_low |= _PAGE_MODIFIED;
271 	if (pte.pte_low & _PAGE_WRITE)
272 		pte.pte_high |= _PAGE_SILENT_WRITE;
273 	return pte;
274 }
275 
276 static inline pte_t pte_mkyoung(pte_t pte)
277 {
278 	pte.pte_low |= _PAGE_ACCESSED;
279 	if (pte.pte_low & _PAGE_READ)
280 		pte.pte_high |= _PAGE_SILENT_READ;
281 	return pte;
282 }
283 #else
284 static inline int pte_write(pte_t pte)	{ return pte_val(pte) & _PAGE_WRITE; }
285 static inline int pte_dirty(pte_t pte)	{ return pte_val(pte) & _PAGE_MODIFIED; }
286 static inline int pte_young(pte_t pte)	{ return pte_val(pte) & _PAGE_ACCESSED; }
287 
288 static inline pte_t pte_wrprotect(pte_t pte)
289 {
290 	pte_val(pte) &= ~(_PAGE_WRITE | _PAGE_SILENT_WRITE);
291 	return pte;
292 }
293 
294 static inline pte_t pte_mkclean(pte_t pte)
295 {
296 	pte_val(pte) &= ~(_PAGE_MODIFIED | _PAGE_SILENT_WRITE);
297 	return pte;
298 }
299 
300 static inline pte_t pte_mkold(pte_t pte)
301 {
302 	pte_val(pte) &= ~(_PAGE_ACCESSED | _PAGE_SILENT_READ);
303 	return pte;
304 }
305 
306 static inline pte_t pte_mkwrite(pte_t pte)
307 {
308 	pte_val(pte) |= _PAGE_WRITE;
309 	if (pte_val(pte) & _PAGE_MODIFIED)
310 		pte_val(pte) |= _PAGE_SILENT_WRITE;
311 	return pte;
312 }
313 
314 static inline pte_t pte_mkdirty(pte_t pte)
315 {
316 	pte_val(pte) |= _PAGE_MODIFIED;
317 	if (pte_val(pte) & _PAGE_WRITE)
318 		pte_val(pte) |= _PAGE_SILENT_WRITE;
319 	return pte;
320 }
321 
322 static inline pte_t pte_mkyoung(pte_t pte)
323 {
324 	pte_val(pte) |= _PAGE_ACCESSED;
325 #ifdef CONFIG_CPU_MIPSR2
326 	if (!(pte_val(pte) & _PAGE_NO_READ))
327 		pte_val(pte) |= _PAGE_SILENT_READ;
328 	else
329 #endif
330 	if (pte_val(pte) & _PAGE_READ)
331 		pte_val(pte) |= _PAGE_SILENT_READ;
332 	return pte;
333 }
334 
335 #ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT
336 static inline int pte_huge(pte_t pte)	{ return pte_val(pte) & _PAGE_HUGE; }
337 
338 static inline pte_t pte_mkhuge(pte_t pte)
339 {
340 	pte_val(pte) |= _PAGE_HUGE;
341 	return pte;
342 }
343 #endif /* CONFIG_MIPS_HUGE_TLB_SUPPORT */
344 #endif
345 static inline int pte_special(pte_t pte)	{ return 0; }
346 static inline pte_t pte_mkspecial(pte_t pte)	{ return pte; }
347 
348 /*
349  * Macro to make mark a page protection value as "uncacheable".	 Note
350  * that "protection" is really a misnomer here as the protection value
351  * contains the memory attribute bits, dirty bits, and various other
352  * bits as well.
353  */
354 #define pgprot_noncached pgprot_noncached
355 
356 static inline pgprot_t pgprot_noncached(pgprot_t _prot)
357 {
358 	unsigned long prot = pgprot_val(_prot);
359 
360 	prot = (prot & ~_CACHE_MASK) | _CACHE_UNCACHED;
361 
362 	return __pgprot(prot);
363 }
364 
365 static inline pgprot_t pgprot_writecombine(pgprot_t _prot)
366 {
367 	unsigned long prot = pgprot_val(_prot);
368 
369 	/* cpu_data[0].writecombine is already shifted by _CACHE_SHIFT */
370 	prot = (prot & ~_CACHE_MASK) | cpu_data[0].writecombine;
371 
372 	return __pgprot(prot);
373 }
374 
375 /*
376  * Conversion functions: convert a page and protection to a page entry,
377  * and a page entry and page directory to the page they refer to.
378  */
379 #define mk_pte(page, pgprot)	pfn_pte(page_to_pfn(page), (pgprot))
380 
381 #if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
382 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
383 {
384 	pte.pte_low  &= (_PAGE_MODIFIED | _PAGE_ACCESSED | _PFNX_MASK);
385 	pte.pte_high &= (_PFN_MASK | _CACHE_MASK);
386 	pte.pte_low  |= pgprot_val(newprot) & ~_PFNX_MASK;
387 	pte.pte_high |= pgprot_val(newprot) & ~_PFN_MASK;
388 	return pte;
389 }
390 #else
391 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
392 {
393 	return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
394 }
395 #endif
396 
397 
398 extern void __update_tlb(struct vm_area_struct *vma, unsigned long address,
399 	pte_t pte);
400 extern void __update_cache(struct vm_area_struct *vma, unsigned long address,
401 	pte_t pte);
402 
403 static inline void update_mmu_cache(struct vm_area_struct *vma,
404 	unsigned long address, pte_t *ptep)
405 {
406 	pte_t pte = *ptep;
407 	__update_tlb(vma, address, pte);
408 	__update_cache(vma, address, pte);
409 }
410 
411 static inline void update_mmu_cache_pmd(struct vm_area_struct *vma,
412 	unsigned long address, pmd_t *pmdp)
413 {
414 	pte_t pte = *(pte_t *)pmdp;
415 
416 	__update_tlb(vma, address, pte);
417 }
418 
419 #define kern_addr_valid(addr)	(1)
420 
421 #ifdef CONFIG_PHYS_ADDR_T_64BIT
422 extern int remap_pfn_range(struct vm_area_struct *vma, unsigned long from, unsigned long pfn, unsigned long size, pgprot_t prot);
423 
424 static inline int io_remap_pfn_range(struct vm_area_struct *vma,
425 		unsigned long vaddr,
426 		unsigned long pfn,
427 		unsigned long size,
428 		pgprot_t prot)
429 {
430 	phys_addr_t phys_addr_high = fixup_bigphys_addr(pfn << PAGE_SHIFT, size);
431 	return remap_pfn_range(vma, vaddr, phys_addr_high >> PAGE_SHIFT, size, prot);
432 }
433 #define io_remap_pfn_range io_remap_pfn_range
434 #endif
435 
436 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
437 
438 extern int has_transparent_hugepage(void);
439 
440 static inline int pmd_trans_huge(pmd_t pmd)
441 {
442 	return !!(pmd_val(pmd) & _PAGE_HUGE);
443 }
444 
445 static inline pmd_t pmd_mkhuge(pmd_t pmd)
446 {
447 	pmd_val(pmd) |= _PAGE_HUGE;
448 
449 	return pmd;
450 }
451 
452 static inline int pmd_trans_splitting(pmd_t pmd)
453 {
454 	return !!(pmd_val(pmd) & _PAGE_SPLITTING);
455 }
456 
457 static inline pmd_t pmd_mksplitting(pmd_t pmd)
458 {
459 	pmd_val(pmd) |= _PAGE_SPLITTING;
460 
461 	return pmd;
462 }
463 
464 extern void set_pmd_at(struct mm_struct *mm, unsigned long addr,
465 		       pmd_t *pmdp, pmd_t pmd);
466 
467 #define __HAVE_ARCH_PMDP_SPLITTING_FLUSH
468 /* Extern to avoid header file madness */
469 extern void pmdp_splitting_flush(struct vm_area_struct *vma,
470 					unsigned long address,
471 					pmd_t *pmdp);
472 
473 #define __HAVE_ARCH_PMD_WRITE
474 static inline int pmd_write(pmd_t pmd)
475 {
476 	return !!(pmd_val(pmd) & _PAGE_WRITE);
477 }
478 
479 static inline pmd_t pmd_wrprotect(pmd_t pmd)
480 {
481 	pmd_val(pmd) &= ~(_PAGE_WRITE | _PAGE_SILENT_WRITE);
482 	return pmd;
483 }
484 
485 static inline pmd_t pmd_mkwrite(pmd_t pmd)
486 {
487 	pmd_val(pmd) |= _PAGE_WRITE;
488 	if (pmd_val(pmd) & _PAGE_MODIFIED)
489 		pmd_val(pmd) |= _PAGE_SILENT_WRITE;
490 
491 	return pmd;
492 }
493 
494 static inline int pmd_dirty(pmd_t pmd)
495 {
496 	return !!(pmd_val(pmd) & _PAGE_MODIFIED);
497 }
498 
499 static inline pmd_t pmd_mkclean(pmd_t pmd)
500 {
501 	pmd_val(pmd) &= ~(_PAGE_MODIFIED | _PAGE_SILENT_WRITE);
502 	return pmd;
503 }
504 
505 static inline pmd_t pmd_mkdirty(pmd_t pmd)
506 {
507 	pmd_val(pmd) |= _PAGE_MODIFIED;
508 	if (pmd_val(pmd) & _PAGE_WRITE)
509 		pmd_val(pmd) |= _PAGE_SILENT_WRITE;
510 
511 	return pmd;
512 }
513 
514 static inline int pmd_young(pmd_t pmd)
515 {
516 	return !!(pmd_val(pmd) & _PAGE_ACCESSED);
517 }
518 
519 static inline pmd_t pmd_mkold(pmd_t pmd)
520 {
521 	pmd_val(pmd) &= ~(_PAGE_ACCESSED|_PAGE_SILENT_READ);
522 
523 	return pmd;
524 }
525 
526 static inline pmd_t pmd_mkyoung(pmd_t pmd)
527 {
528 	pmd_val(pmd) |= _PAGE_ACCESSED;
529 
530 #ifdef CONFIG_CPU_MIPSR2
531 	if (!(pmd_val(pmd) & _PAGE_NO_READ))
532 		pmd_val(pmd) |= _PAGE_SILENT_READ;
533 	else
534 #endif
535 	if (pmd_val(pmd) & _PAGE_READ)
536 		pmd_val(pmd) |= _PAGE_SILENT_READ;
537 
538 	return pmd;
539 }
540 
541 /* Extern to avoid header file madness */
542 extern pmd_t mk_pmd(struct page *page, pgprot_t prot);
543 
544 static inline unsigned long pmd_pfn(pmd_t pmd)
545 {
546 	return pmd_val(pmd) >> _PFN_SHIFT;
547 }
548 
549 static inline struct page *pmd_page(pmd_t pmd)
550 {
551 	if (pmd_trans_huge(pmd))
552 		return pfn_to_page(pmd_pfn(pmd));
553 
554 	return pfn_to_page(pmd_phys(pmd) >> PAGE_SHIFT);
555 }
556 
557 static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
558 {
559 	pmd_val(pmd) = (pmd_val(pmd) & _PAGE_CHG_MASK) | pgprot_val(newprot);
560 	return pmd;
561 }
562 
563 static inline pmd_t pmd_mknotpresent(pmd_t pmd)
564 {
565 	pmd_val(pmd) &= ~(_PAGE_PRESENT | _PAGE_VALID | _PAGE_DIRTY);
566 
567 	return pmd;
568 }
569 
570 /*
571  * The generic version pmdp_huge_get_and_clear uses a version of pmd_clear() with a
572  * different prototype.
573  */
574 #define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR
575 static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
576 					    unsigned long address, pmd_t *pmdp)
577 {
578 	pmd_t old = *pmdp;
579 
580 	pmd_clear(pmdp);
581 
582 	return old;
583 }
584 
585 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
586 
587 #include <asm-generic/pgtable.h>
588 
589 /*
590  * uncached accelerated TLB map for video memory access
591  */
592 #ifdef CONFIG_CPU_SUPPORTS_UNCACHED_ACCELERATED
593 #define __HAVE_PHYS_MEM_ACCESS_PROT
594 
595 struct file;
596 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
597 		unsigned long size, pgprot_t vma_prot);
598 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
599 		unsigned long size, pgprot_t *vma_prot);
600 #endif
601 
602 /*
603  * We provide our own get_unmapped area to cope with the virtual aliasing
604  * constraints placed on us by the cache architecture.
605  */
606 #define HAVE_ARCH_UNMAPPED_AREA
607 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
608 
609 /*
610  * No page table caches to initialise
611  */
612 #define pgtable_cache_init()	do { } while (0)
613 
614 #endif /* _ASM_PGTABLE_H */
615