xref: /openbmc/linux/arch/ia64/include/asm/pgtable.h (revision 6c452cff)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_IA64_PGTABLE_H
3 #define _ASM_IA64_PGTABLE_H
4 
5 /*
6  * This file contains the functions and defines necessary to modify and use
7  * the IA-64 page table tree.
8  *
9  * This hopefully works with any (fixed) IA-64 page-size, as defined
10  * in <asm/page.h>.
11  *
12  * Copyright (C) 1998-2005 Hewlett-Packard Co
13  *	David Mosberger-Tang <davidm@hpl.hp.com>
14  */
15 
16 
17 #include <asm/mman.h>
18 #include <asm/page.h>
19 #include <asm/processor.h>
20 #include <asm/types.h>
21 
22 #define IA64_MAX_PHYS_BITS	50	/* max. number of physical address bits (architected) */
23 
24 /*
25  * First, define the various bits in a PTE.  Note that the PTE format
26  * matches the VHPT short format, the firt doubleword of the VHPD long
27  * format, and the first doubleword of the TLB insertion format.
28  */
29 #define _PAGE_P_BIT		0
30 #define _PAGE_A_BIT		5
31 #define _PAGE_D_BIT		6
32 
33 #define _PAGE_P			(1 << _PAGE_P_BIT)	/* page present bit */
34 #define _PAGE_MA_WB		(0x0 <<  2)	/* write back memory attribute */
35 #define _PAGE_MA_UC		(0x4 <<  2)	/* uncacheable memory attribute */
36 #define _PAGE_MA_UCE		(0x5 <<  2)	/* UC exported attribute */
37 #define _PAGE_MA_WC		(0x6 <<  2)	/* write coalescing memory attribute */
38 #define _PAGE_MA_NAT		(0x7 <<  2)	/* not-a-thing attribute */
39 #define _PAGE_MA_MASK		(0x7 <<  2)
40 #define _PAGE_PL_0		(0 <<  7)	/* privilege level 0 (kernel) */
41 #define _PAGE_PL_1		(1 <<  7)	/* privilege level 1 (unused) */
42 #define _PAGE_PL_2		(2 <<  7)	/* privilege level 2 (unused) */
43 #define _PAGE_PL_3		(3 <<  7)	/* privilege level 3 (user) */
44 #define _PAGE_PL_MASK		(3 <<  7)
45 #define _PAGE_AR_R		(0 <<  9)	/* read only */
46 #define _PAGE_AR_RX		(1 <<  9)	/* read & execute */
47 #define _PAGE_AR_RW		(2 <<  9)	/* read & write */
48 #define _PAGE_AR_RWX		(3 <<  9)	/* read, write & execute */
49 #define _PAGE_AR_R_RW		(4 <<  9)	/* read / read & write */
50 #define _PAGE_AR_RX_RWX		(5 <<  9)	/* read & exec / read, write & exec */
51 #define _PAGE_AR_RWX_RW		(6 <<  9)	/* read, write & exec / read & write */
52 #define _PAGE_AR_X_RX		(7 <<  9)	/* exec & promote / read & exec */
53 #define _PAGE_AR_MASK		(7 <<  9)
54 #define _PAGE_AR_SHIFT		9
55 #define _PAGE_A			(1 << _PAGE_A_BIT)	/* page accessed bit */
56 #define _PAGE_D			(1 << _PAGE_D_BIT)	/* page dirty bit */
57 #define _PAGE_PPN_MASK		(((__IA64_UL(1) << IA64_MAX_PHYS_BITS) - 1) & ~0xfffUL)
58 #define _PAGE_ED		(__IA64_UL(1) << 52)	/* exception deferral */
59 #define _PAGE_PROTNONE		(__IA64_UL(1) << 63)
60 
61 #define _PFN_MASK		_PAGE_PPN_MASK
62 /* Mask of bits which may be changed by pte_modify(); the odd bits are there for _PAGE_PROTNONE */
63 #define _PAGE_CHG_MASK	(_PAGE_P | _PAGE_PROTNONE | _PAGE_PL_MASK | _PAGE_AR_MASK | _PAGE_ED)
64 
65 #define _PAGE_SIZE_4K	12
66 #define _PAGE_SIZE_8K	13
67 #define _PAGE_SIZE_16K	14
68 #define _PAGE_SIZE_64K	16
69 #define _PAGE_SIZE_256K	18
70 #define _PAGE_SIZE_1M	20
71 #define _PAGE_SIZE_4M	22
72 #define _PAGE_SIZE_16M	24
73 #define _PAGE_SIZE_64M	26
74 #define _PAGE_SIZE_256M	28
75 #define _PAGE_SIZE_1G	30
76 #define _PAGE_SIZE_4G	32
77 
78 #define __ACCESS_BITS		_PAGE_ED | _PAGE_A | _PAGE_P | _PAGE_MA_WB
79 #define __DIRTY_BITS_NO_ED	_PAGE_A | _PAGE_P | _PAGE_D | _PAGE_MA_WB
80 #define __DIRTY_BITS		_PAGE_ED | __DIRTY_BITS_NO_ED
81 
82 /*
83  * How many pointers will a page table level hold expressed in shift
84  */
85 #define PTRS_PER_PTD_SHIFT	(PAGE_SHIFT-3)
86 
87 /*
88  * Definitions for fourth level:
89  */
90 #define PTRS_PER_PTE	(__IA64_UL(1) << (PTRS_PER_PTD_SHIFT))
91 
92 /*
93  * Definitions for third level:
94  *
95  * PMD_SHIFT determines the size of the area a third-level page table
96  * can map.
97  */
98 #define PMD_SHIFT	(PAGE_SHIFT + (PTRS_PER_PTD_SHIFT))
99 #define PMD_SIZE	(1UL << PMD_SHIFT)
100 #define PMD_MASK	(~(PMD_SIZE-1))
101 #define PTRS_PER_PMD	(1UL << (PTRS_PER_PTD_SHIFT))
102 
103 #if CONFIG_PGTABLE_LEVELS == 4
104 /*
105  * Definitions for second level:
106  *
107  * PUD_SHIFT determines the size of the area a second-level page table
108  * can map.
109  */
110 #define PUD_SHIFT	(PMD_SHIFT + (PTRS_PER_PTD_SHIFT))
111 #define PUD_SIZE	(1UL << PUD_SHIFT)
112 #define PUD_MASK	(~(PUD_SIZE-1))
113 #define PTRS_PER_PUD	(1UL << (PTRS_PER_PTD_SHIFT))
114 #endif
115 
116 /*
117  * Definitions for first level:
118  *
119  * PGDIR_SHIFT determines what a first-level page table entry can map.
120  */
121 #if CONFIG_PGTABLE_LEVELS == 4
122 #define PGDIR_SHIFT		(PUD_SHIFT + (PTRS_PER_PTD_SHIFT))
123 #else
124 #define PGDIR_SHIFT		(PMD_SHIFT + (PTRS_PER_PTD_SHIFT))
125 #endif
126 #define PGDIR_SIZE		(__IA64_UL(1) << PGDIR_SHIFT)
127 #define PGDIR_MASK		(~(PGDIR_SIZE-1))
128 #define PTRS_PER_PGD_SHIFT	PTRS_PER_PTD_SHIFT
129 #define PTRS_PER_PGD		(1UL << PTRS_PER_PGD_SHIFT)
130 #define USER_PTRS_PER_PGD	(5*PTRS_PER_PGD/8)	/* regions 0-4 are user regions */
131 
132 /*
133  * All the normal masks have the "page accessed" bits on, as any time
134  * they are used, the page is accessed. They are cleared only by the
135  * page-out routines.
136  */
137 #define PAGE_NONE	__pgprot(_PAGE_PROTNONE | _PAGE_A)
138 #define PAGE_SHARED	__pgprot(__ACCESS_BITS | _PAGE_PL_3 | _PAGE_AR_RW)
139 #define PAGE_READONLY	__pgprot(__ACCESS_BITS | _PAGE_PL_3 | _PAGE_AR_R)
140 #define PAGE_COPY	__pgprot(__ACCESS_BITS | _PAGE_PL_3 | _PAGE_AR_R)
141 #define PAGE_COPY_EXEC	__pgprot(__ACCESS_BITS | _PAGE_PL_3 | _PAGE_AR_RX)
142 #define PAGE_GATE	__pgprot(__ACCESS_BITS | _PAGE_PL_0 | _PAGE_AR_X_RX)
143 #define PAGE_KERNEL	__pgprot(__DIRTY_BITS  | _PAGE_PL_0 | _PAGE_AR_RWX)
144 #define PAGE_KERNELRX	__pgprot(__ACCESS_BITS | _PAGE_PL_0 | _PAGE_AR_RX)
145 #define PAGE_KERNEL_UC	__pgprot(__DIRTY_BITS  | _PAGE_PL_0 | _PAGE_AR_RWX | \
146 				 _PAGE_MA_UC)
147 
148 # ifndef __ASSEMBLY__
149 
150 #include <linux/sched/mm.h>	/* for mm_struct */
151 #include <linux/bitops.h>
152 #include <asm/cacheflush.h>
153 #include <asm/mmu_context.h>
154 
155 /*
156  * Next come the mappings that determine how mmap() protection bits
157  * (PROT_EXEC, PROT_READ, PROT_WRITE, PROT_NONE) get implemented.  The
158  * _P version gets used for a private shared memory segment, the _S
159  * version gets used for a shared memory segment with MAP_SHARED on.
160  * In a private shared memory segment, we do a copy-on-write if a task
161  * attempts to write to the page.
162  */
163 	/* xwr */
164 #define pgd_ERROR(e)	printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
165 #if CONFIG_PGTABLE_LEVELS == 4
166 #define pud_ERROR(e)	printk("%s:%d: bad pud %016lx.\n", __FILE__, __LINE__, pud_val(e))
167 #endif
168 #define pmd_ERROR(e)	printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
169 #define pte_ERROR(e)	printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
170 
171 
172 /*
173  * Some definitions to translate between mem_map, PTEs, and page addresses:
174  */
175 
176 
177 /* Quick test to see if ADDR is a (potentially) valid physical address. */
178 static inline long
179 ia64_phys_addr_valid (unsigned long addr)
180 {
181 	return (addr & (local_cpu_data->unimpl_pa_mask)) == 0;
182 }
183 
184 /*
185  * kern_addr_valid(ADDR) tests if ADDR is pointing to valid kernel
186  * memory.  For the return value to be meaningful, ADDR must be >=
187  * PAGE_OFFSET.  This operation can be relatively expensive (e.g.,
188  * require a hash-, or multi-level tree-lookup or something of that
189  * sort) but it guarantees to return TRUE only if accessing the page
190  * at that address does not cause an error.  Note that there may be
191  * addresses for which kern_addr_valid() returns FALSE even though an
192  * access would not cause an error (e.g., this is typically true for
193  * memory mapped I/O regions.
194  *
195  * XXX Need to implement this for IA-64.
196  */
197 #define kern_addr_valid(addr)	(1)
198 
199 
200 /*
201  * Now come the defines and routines to manage and access the three-level
202  * page table.
203  */
204 
205 
206 #define VMALLOC_START		(RGN_BASE(RGN_GATE) + 0x200000000UL)
207 #if defined(CONFIG_SPARSEMEM) && defined(CONFIG_SPARSEMEM_VMEMMAP)
208 /* SPARSEMEM_VMEMMAP uses half of vmalloc... */
209 # define VMALLOC_END		(RGN_BASE(RGN_GATE) + (1UL << (4*PAGE_SHIFT - 10)))
210 # define vmemmap		((struct page *)VMALLOC_END)
211 #else
212 # define VMALLOC_END		(RGN_BASE(RGN_GATE) + (1UL << (4*PAGE_SHIFT - 9)))
213 #endif
214 
215 /* fs/proc/kcore.c */
216 #define	kc_vaddr_to_offset(v) ((v) - RGN_BASE(RGN_GATE))
217 #define	kc_offset_to_vaddr(o) ((o) + RGN_BASE(RGN_GATE))
218 
219 #define RGN_MAP_SHIFT (PGDIR_SHIFT + PTRS_PER_PGD_SHIFT - 3)
220 #define RGN_MAP_LIMIT	((1UL << RGN_MAP_SHIFT) - PAGE_SIZE)	/* per region addr limit */
221 
222 /*
223  * Conversion functions: convert page frame number (pfn) and a protection value to a page
224  * table entry (pte).
225  */
226 #define pfn_pte(pfn, pgprot) \
227 ({ pte_t __pte; pte_val(__pte) = ((pfn) << PAGE_SHIFT) | pgprot_val(pgprot); __pte; })
228 
229 /* Extract pfn from pte.  */
230 #define pte_pfn(_pte)		((pte_val(_pte) & _PFN_MASK) >> PAGE_SHIFT)
231 
232 #define mk_pte(page, pgprot)	pfn_pte(page_to_pfn(page), (pgprot))
233 
234 /* This takes a physical page address that is used by the remapping functions */
235 #define mk_pte_phys(physpage, pgprot) \
236 ({ pte_t __pte; pte_val(__pte) = physpage + pgprot_val(pgprot); __pte; })
237 
238 #define pte_modify(_pte, newprot) \
239 	(__pte((pte_val(_pte) & ~_PAGE_CHG_MASK) | (pgprot_val(newprot) & _PAGE_CHG_MASK)))
240 
241 #define pte_none(pte) 			(!pte_val(pte))
242 #define pte_present(pte)		(pte_val(pte) & (_PAGE_P | _PAGE_PROTNONE))
243 #define pte_clear(mm,addr,pte)		(pte_val(*(pte)) = 0UL)
244 /* pte_page() returns the "struct page *" corresponding to the PTE: */
245 #define pte_page(pte)			virt_to_page(((pte_val(pte) & _PFN_MASK) + PAGE_OFFSET))
246 
247 #define pmd_none(pmd)			(!pmd_val(pmd))
248 #define pmd_bad(pmd)			(!ia64_phys_addr_valid(pmd_val(pmd)))
249 #define pmd_present(pmd)		(pmd_val(pmd) != 0UL)
250 #define pmd_clear(pmdp)			(pmd_val(*(pmdp)) = 0UL)
251 #define pmd_page_vaddr(pmd)		((unsigned long) __va(pmd_val(pmd) & _PFN_MASK))
252 #define pmd_pfn(pmd)			((pmd_val(pmd) & _PFN_MASK) >> PAGE_SHIFT)
253 #define pmd_page(pmd)			virt_to_page((pmd_val(pmd) + PAGE_OFFSET))
254 
255 #define pud_none(pud)			(!pud_val(pud))
256 #define pud_bad(pud)			(!ia64_phys_addr_valid(pud_val(pud)))
257 #define pud_present(pud)		(pud_val(pud) != 0UL)
258 #define pud_clear(pudp)			(pud_val(*(pudp)) = 0UL)
259 #define pud_pgtable(pud)		((pmd_t *) __va(pud_val(pud) & _PFN_MASK))
260 #define pud_page(pud)			virt_to_page((pud_val(pud) + PAGE_OFFSET))
261 
262 #if CONFIG_PGTABLE_LEVELS == 4
263 #define p4d_none(p4d)			(!p4d_val(p4d))
264 #define p4d_bad(p4d)			(!ia64_phys_addr_valid(p4d_val(p4d)))
265 #define p4d_present(p4d)		(p4d_val(p4d) != 0UL)
266 #define p4d_clear(p4dp)			(p4d_val(*(p4dp)) = 0UL)
267 #define p4d_pgtable(p4d)		((pud_t *) __va(p4d_val(p4d) & _PFN_MASK))
268 #define p4d_page(p4d)			virt_to_page((p4d_val(p4d) + PAGE_OFFSET))
269 #endif
270 
271 /*
272  * The following have defined behavior only work if pte_present() is true.
273  */
274 #define pte_write(pte)	((unsigned) (((pte_val(pte) & _PAGE_AR_MASK) >> _PAGE_AR_SHIFT) - 2) <= 4)
275 #define pte_exec(pte)		((pte_val(pte) & _PAGE_AR_RX) != 0)
276 #define pte_dirty(pte)		((pte_val(pte) & _PAGE_D) != 0)
277 #define pte_young(pte)		((pte_val(pte) & _PAGE_A) != 0)
278 
279 /*
280  * Note: we convert AR_RWX to AR_RX and AR_RW to AR_R by clearing the 2nd bit in the
281  * access rights:
282  */
283 #define pte_wrprotect(pte)	(__pte(pte_val(pte) & ~_PAGE_AR_RW))
284 #define pte_mkwrite(pte)	(__pte(pte_val(pte) | _PAGE_AR_RW))
285 #define pte_mkold(pte)		(__pte(pte_val(pte) & ~_PAGE_A))
286 #define pte_mkyoung(pte)	(__pte(pte_val(pte) | _PAGE_A))
287 #define pte_mkclean(pte)	(__pte(pte_val(pte) & ~_PAGE_D))
288 #define pte_mkdirty(pte)	(__pte(pte_val(pte) | _PAGE_D))
289 #define pte_mkhuge(pte)		(__pte(pte_val(pte)))
290 
291 /*
292  * Because ia64's Icache and Dcache is not coherent (on a cpu), we need to
293  * sync icache and dcache when we insert *new* executable page.
294  *  __ia64_sync_icache_dcache() check Pg_arch_1 bit and flush icache
295  * if necessary.
296  *
297  *  set_pte() is also called by the kernel, but we can expect that the kernel
298  *  flushes icache explicitly if necessary.
299  */
300 #define pte_present_exec_user(pte)\
301 	((pte_val(pte) & (_PAGE_P | _PAGE_PL_MASK | _PAGE_AR_RX)) == \
302 		(_PAGE_P | _PAGE_PL_3 | _PAGE_AR_RX))
303 
304 extern void __ia64_sync_icache_dcache(pte_t pteval);
305 static inline void set_pte(pte_t *ptep, pte_t pteval)
306 {
307 	/* page is present && page is user  && page is executable
308 	 * && (page swapin or new page or page migration
309 	 *	|| copy_on_write with page copying.)
310 	 */
311 	if (pte_present_exec_user(pteval) &&
312 	    (!pte_present(*ptep) ||
313 		pte_pfn(*ptep) != pte_pfn(pteval)))
314 		/* load_module() calles flush_icache_range() explicitly*/
315 		__ia64_sync_icache_dcache(pteval);
316 	*ptep = pteval;
317 }
318 
319 #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
320 
321 /*
322  * Make page protection values cacheable, uncacheable, or write-
323  * combining.  Note that "protection" is really a misnomer here as the
324  * protection value contains the memory attribute bits, dirty bits, and
325  * various other bits as well.
326  */
327 #define pgprot_cacheable(prot)		__pgprot((pgprot_val(prot) & ~_PAGE_MA_MASK) | _PAGE_MA_WB)
328 #define pgprot_noncached(prot)		__pgprot((pgprot_val(prot) & ~_PAGE_MA_MASK) | _PAGE_MA_UC)
329 #define pgprot_writecombine(prot)	__pgprot((pgprot_val(prot) & ~_PAGE_MA_MASK) | _PAGE_MA_WC)
330 
331 struct file;
332 extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
333 				     unsigned long size, pgprot_t vma_prot);
334 #define __HAVE_PHYS_MEM_ACCESS_PROT
335 
336 static inline unsigned long
337 pgd_index (unsigned long address)
338 {
339 	unsigned long region = address >> 61;
340 	unsigned long l1index = (address >> PGDIR_SHIFT) & ((PTRS_PER_PGD >> 3) - 1);
341 
342 	return (region << (PAGE_SHIFT - 6)) | l1index;
343 }
344 #define pgd_index pgd_index
345 
346 /*
347  * In the kernel's mapped region we know everything is in region number 5, so
348  * as an optimisation its PGD already points to the area for that region.
349  * However, this also means that we cannot use pgd_index() and we must
350  * never add the region here.
351  */
352 #define pgd_offset_k(addr) \
353 	(init_mm.pgd + (((addr) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1)))
354 
355 /* Look up a pgd entry in the gate area.  On IA-64, the gate-area
356    resides in the kernel-mapped segment, hence we use pgd_offset_k()
357    here.  */
358 #define pgd_offset_gate(mm, addr)	pgd_offset_k(addr)
359 
360 /* atomic versions of the some PTE manipulations: */
361 
362 static inline int
363 ptep_test_and_clear_young (struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
364 {
365 #ifdef CONFIG_SMP
366 	if (!pte_young(*ptep))
367 		return 0;
368 	return test_and_clear_bit(_PAGE_A_BIT, ptep);
369 #else
370 	pte_t pte = *ptep;
371 	if (!pte_young(pte))
372 		return 0;
373 	set_pte_at(vma->vm_mm, addr, ptep, pte_mkold(pte));
374 	return 1;
375 #endif
376 }
377 
378 static inline pte_t
379 ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
380 {
381 #ifdef CONFIG_SMP
382 	return __pte(xchg((long *) ptep, 0));
383 #else
384 	pte_t pte = *ptep;
385 	pte_clear(mm, addr, ptep);
386 	return pte;
387 #endif
388 }
389 
390 static inline void
391 ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
392 {
393 #ifdef CONFIG_SMP
394 	unsigned long new, old;
395 
396 	do {
397 		old = pte_val(*ptep);
398 		new = pte_val(pte_wrprotect(__pte (old)));
399 	} while (cmpxchg((unsigned long *) ptep, old, new) != old);
400 #else
401 	pte_t old_pte = *ptep;
402 	set_pte_at(mm, addr, ptep, pte_wrprotect(old_pte));
403 #endif
404 }
405 
406 static inline int
407 pte_same (pte_t a, pte_t b)
408 {
409 	return pte_val(a) == pte_val(b);
410 }
411 
412 #define update_mmu_cache(vma, address, ptep) do { } while (0)
413 
414 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
415 extern void paging_init (void);
416 
417 /*
418  * Note: The macros below rely on the fact that MAX_SWAPFILES_SHIFT <= number of
419  *	 bits in the swap-type field of the swap pte.  It would be nice to
420  *	 enforce that, but we can't easily include <linux/swap.h> here.
421  *	 (Of course, better still would be to define MAX_SWAPFILES_SHIFT here...).
422  *
423  * Format of swap pte:
424  *	bit   0   : present bit (must be zero)
425  *	bits  1- 7: swap-type
426  *	bits  8-62: swap offset
427  *	bit  63   : _PAGE_PROTNONE bit
428  */
429 #define __swp_type(entry)		(((entry).val >> 1) & 0x7f)
430 #define __swp_offset(entry)		(((entry).val << 1) >> 9)
431 #define __swp_entry(type,offset)	((swp_entry_t) { ((type) << 1) | ((long) (offset) << 8) })
432 #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
433 #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
434 
435 /*
436  * ZERO_PAGE is a global shared page that is always zero: used
437  * for zero-mapped memory areas etc..
438  */
439 extern unsigned long empty_zero_page[PAGE_SIZE/sizeof(unsigned long)];
440 extern struct page *zero_page_memmap_ptr;
441 #define ZERO_PAGE(vaddr) (zero_page_memmap_ptr)
442 
443 /* We provide our own get_unmapped_area to cope with VA holes for userland */
444 #define HAVE_ARCH_UNMAPPED_AREA
445 
446 #ifdef CONFIG_HUGETLB_PAGE
447 #define HUGETLB_PGDIR_SHIFT	(HPAGE_SHIFT + 2*(PAGE_SHIFT-3))
448 #define HUGETLB_PGDIR_SIZE	(__IA64_UL(1) << HUGETLB_PGDIR_SHIFT)
449 #define HUGETLB_PGDIR_MASK	(~(HUGETLB_PGDIR_SIZE-1))
450 #endif
451 
452 
453 #define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
454 /*
455  * Update PTEP with ENTRY, which is guaranteed to be a less
456  * restrictive PTE.  That is, ENTRY may have the ACCESSED, DIRTY, and
457  * WRITABLE bits turned on, when the value at PTEP did not.  The
458  * WRITABLE bit may only be turned if SAFELY_WRITABLE is TRUE.
459  *
460  * SAFELY_WRITABLE is TRUE if we can update the value at PTEP without
461  * having to worry about races.  On SMP machines, there are only two
462  * cases where this is true:
463  *
464  *	(1) *PTEP has the PRESENT bit turned OFF
465  *	(2) ENTRY has the DIRTY bit turned ON
466  *
467  * On ia64, we could implement this routine with a cmpxchg()-loop
468  * which ORs in the _PAGE_A/_PAGE_D bit if they're set in ENTRY.
469  * However, like on x86, we can get a more streamlined version by
470  * observing that it is OK to drop ACCESSED bit updates when
471  * SAFELY_WRITABLE is FALSE.  Besides being rare, all that would do is
472  * result in an extra Access-bit fault, which would then turn on the
473  * ACCESSED bit in the low-level fault handler (iaccess_bit or
474  * daccess_bit in ivt.S).
475  */
476 #ifdef CONFIG_SMP
477 # define ptep_set_access_flags(__vma, __addr, __ptep, __entry, __safely_writable) \
478 ({									\
479 	int __changed = !pte_same(*(__ptep), __entry);			\
480 	if (__changed && __safely_writable) {				\
481 		set_pte(__ptep, __entry);				\
482 		flush_tlb_page(__vma, __addr);				\
483 	}								\
484 	__changed;							\
485 })
486 #else
487 # define ptep_set_access_flags(__vma, __addr, __ptep, __entry, __safely_writable) \
488 ({									\
489 	int __changed = !pte_same(*(__ptep), __entry);			\
490 	if (__changed) {						\
491 		set_pte_at((__vma)->vm_mm, (__addr), __ptep, __entry);	\
492 		flush_tlb_page(__vma, __addr);				\
493 	}								\
494 	__changed;							\
495 })
496 #endif
497 # endif /* !__ASSEMBLY__ */
498 
499 /*
500  * Identity-mapped regions use a large page size.  We'll call such large pages
501  * "granules".  If you can think of a better name that's unambiguous, let me
502  * know...
503  */
504 #if defined(CONFIG_IA64_GRANULE_64MB)
505 # define IA64_GRANULE_SHIFT	_PAGE_SIZE_64M
506 #elif defined(CONFIG_IA64_GRANULE_16MB)
507 # define IA64_GRANULE_SHIFT	_PAGE_SIZE_16M
508 #endif
509 #define IA64_GRANULE_SIZE	(1 << IA64_GRANULE_SHIFT)
510 /*
511  * log2() of the page size we use to map the kernel image (IA64_TR_KERNEL):
512  */
513 #define KERNEL_TR_PAGE_SHIFT	_PAGE_SIZE_64M
514 #define KERNEL_TR_PAGE_SIZE	(1 << KERNEL_TR_PAGE_SHIFT)
515 
516 /* These tell get_user_pages() that the first gate page is accessible from user-level.  */
517 #define FIXADDR_USER_START	GATE_ADDR
518 #ifdef HAVE_BUGGY_SEGREL
519 # define FIXADDR_USER_END	(GATE_ADDR + 2*PAGE_SIZE)
520 #else
521 # define FIXADDR_USER_END	(GATE_ADDR + 2*PERCPU_PAGE_SIZE)
522 #endif
523 
524 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
525 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
526 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
527 #define __HAVE_ARCH_PTE_SAME
528 #define __HAVE_ARCH_PGD_OFFSET_GATE
529 
530 
531 #if CONFIG_PGTABLE_LEVELS == 3
532 #include <asm-generic/pgtable-nopud.h>
533 #endif
534 #include <asm-generic/pgtable-nop4d.h>
535 
536 #endif /* _ASM_IA64_PGTABLE_H */
537