xref: /openbmc/linux/arch/ia64/include/asm/pgtable.h (revision 65844828)
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  * Now come the defines and routines to manage and access the three-level
186  * page table.
187  */
188 
189 
190 #define VMALLOC_START		(RGN_BASE(RGN_GATE) + 0x200000000UL)
191 #if defined(CONFIG_SPARSEMEM) && defined(CONFIG_SPARSEMEM_VMEMMAP)
192 /* SPARSEMEM_VMEMMAP uses half of vmalloc... */
193 # define VMALLOC_END		(RGN_BASE(RGN_GATE) + (1UL << (4*PAGE_SHIFT - 10)))
194 # define vmemmap		((struct page *)VMALLOC_END)
195 #else
196 # define VMALLOC_END		(RGN_BASE(RGN_GATE) + (1UL << (4*PAGE_SHIFT - 9)))
197 #endif
198 
199 /* fs/proc/kcore.c */
200 #define	kc_vaddr_to_offset(v) ((v) - RGN_BASE(RGN_GATE))
201 #define	kc_offset_to_vaddr(o) ((o) + RGN_BASE(RGN_GATE))
202 
203 #define RGN_MAP_SHIFT (PGDIR_SHIFT + PTRS_PER_PGD_SHIFT - 3)
204 #define RGN_MAP_LIMIT	((1UL << RGN_MAP_SHIFT) - PAGE_SIZE)	/* per region addr limit */
205 
206 /*
207  * Conversion functions: convert page frame number (pfn) and a protection value to a page
208  * table entry (pte).
209  */
210 #define pfn_pte(pfn, pgprot) \
211 ({ pte_t __pte; pte_val(__pte) = ((pfn) << PAGE_SHIFT) | pgprot_val(pgprot); __pte; })
212 
213 /* Extract pfn from pte.  */
214 #define pte_pfn(_pte)		((pte_val(_pte) & _PFN_MASK) >> PAGE_SHIFT)
215 
216 #define mk_pte(page, pgprot)	pfn_pte(page_to_pfn(page), (pgprot))
217 
218 /* This takes a physical page address that is used by the remapping functions */
219 #define mk_pte_phys(physpage, pgprot) \
220 ({ pte_t __pte; pte_val(__pte) = physpage + pgprot_val(pgprot); __pte; })
221 
222 #define pte_modify(_pte, newprot) \
223 	(__pte((pte_val(_pte) & ~_PAGE_CHG_MASK) | (pgprot_val(newprot) & _PAGE_CHG_MASK)))
224 
225 #define pte_none(pte) 			(!pte_val(pte))
226 #define pte_present(pte)		(pte_val(pte) & (_PAGE_P | _PAGE_PROTNONE))
227 #define pte_clear(mm,addr,pte)		(pte_val(*(pte)) = 0UL)
228 /* pte_page() returns the "struct page *" corresponding to the PTE: */
229 #define pte_page(pte)			virt_to_page(((pte_val(pte) & _PFN_MASK) + PAGE_OFFSET))
230 
231 #define pmd_none(pmd)			(!pmd_val(pmd))
232 #define pmd_bad(pmd)			(!ia64_phys_addr_valid(pmd_val(pmd)))
233 #define pmd_present(pmd)		(pmd_val(pmd) != 0UL)
234 #define pmd_clear(pmdp)			(pmd_val(*(pmdp)) = 0UL)
235 #define pmd_page_vaddr(pmd)		((unsigned long) __va(pmd_val(pmd) & _PFN_MASK))
236 #define pmd_pfn(pmd)			((pmd_val(pmd) & _PFN_MASK) >> PAGE_SHIFT)
237 #define pmd_page(pmd)			virt_to_page((pmd_val(pmd) + PAGE_OFFSET))
238 
239 #define pud_none(pud)			(!pud_val(pud))
240 #define pud_bad(pud)			(!ia64_phys_addr_valid(pud_val(pud)))
241 #define pud_present(pud)		(pud_val(pud) != 0UL)
242 #define pud_clear(pudp)			(pud_val(*(pudp)) = 0UL)
243 #define pud_pgtable(pud)		((pmd_t *) __va(pud_val(pud) & _PFN_MASK))
244 #define pud_page(pud)			virt_to_page((pud_val(pud) + PAGE_OFFSET))
245 
246 #if CONFIG_PGTABLE_LEVELS == 4
247 #define p4d_none(p4d)			(!p4d_val(p4d))
248 #define p4d_bad(p4d)			(!ia64_phys_addr_valid(p4d_val(p4d)))
249 #define p4d_present(p4d)		(p4d_val(p4d) != 0UL)
250 #define p4d_clear(p4dp)			(p4d_val(*(p4dp)) = 0UL)
251 #define p4d_pgtable(p4d)		((pud_t *) __va(p4d_val(p4d) & _PFN_MASK))
252 #define p4d_page(p4d)			virt_to_page((p4d_val(p4d) + PAGE_OFFSET))
253 #endif
254 
255 /*
256  * The following have defined behavior only work if pte_present() is true.
257  */
258 #define pte_write(pte)	((unsigned) (((pte_val(pte) & _PAGE_AR_MASK) >> _PAGE_AR_SHIFT) - 2) <= 4)
259 #define pte_exec(pte)		((pte_val(pte) & _PAGE_AR_RX) != 0)
260 #define pte_dirty(pte)		((pte_val(pte) & _PAGE_D) != 0)
261 #define pte_young(pte)		((pte_val(pte) & _PAGE_A) != 0)
262 
263 /*
264  * Note: we convert AR_RWX to AR_RX and AR_RW to AR_R by clearing the 2nd bit in the
265  * access rights:
266  */
267 #define pte_wrprotect(pte)	(__pte(pte_val(pte) & ~_PAGE_AR_RW))
268 #define pte_mkwrite(pte)	(__pte(pte_val(pte) | _PAGE_AR_RW))
269 #define pte_mkold(pte)		(__pte(pte_val(pte) & ~_PAGE_A))
270 #define pte_mkyoung(pte)	(__pte(pte_val(pte) | _PAGE_A))
271 #define pte_mkclean(pte)	(__pte(pte_val(pte) & ~_PAGE_D))
272 #define pte_mkdirty(pte)	(__pte(pte_val(pte) | _PAGE_D))
273 #define pte_mkhuge(pte)		(__pte(pte_val(pte)))
274 
275 /*
276  * Because ia64's Icache and Dcache is not coherent (on a cpu), we need to
277  * sync icache and dcache when we insert *new* executable page.
278  *  __ia64_sync_icache_dcache() check Pg_arch_1 bit and flush icache
279  * if necessary.
280  *
281  *  set_pte() is also called by the kernel, but we can expect that the kernel
282  *  flushes icache explicitly if necessary.
283  */
284 #define pte_present_exec_user(pte)\
285 	((pte_val(pte) & (_PAGE_P | _PAGE_PL_MASK | _PAGE_AR_RX)) == \
286 		(_PAGE_P | _PAGE_PL_3 | _PAGE_AR_RX))
287 
288 extern void __ia64_sync_icache_dcache(pte_t pteval);
289 static inline void set_pte(pte_t *ptep, pte_t pteval)
290 {
291 	/* page is present && page is user  && page is executable
292 	 * && (page swapin or new page or page migration
293 	 *	|| copy_on_write with page copying.)
294 	 */
295 	if (pte_present_exec_user(pteval) &&
296 	    (!pte_present(*ptep) ||
297 		pte_pfn(*ptep) != pte_pfn(pteval)))
298 		/* load_module() calles flush_icache_range() explicitly*/
299 		__ia64_sync_icache_dcache(pteval);
300 	*ptep = pteval;
301 }
302 
303 #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
304 
305 /*
306  * Make page protection values cacheable, uncacheable, or write-
307  * combining.  Note that "protection" is really a misnomer here as the
308  * protection value contains the memory attribute bits, dirty bits, and
309  * various other bits as well.
310  */
311 #define pgprot_cacheable(prot)		__pgprot((pgprot_val(prot) & ~_PAGE_MA_MASK) | _PAGE_MA_WB)
312 #define pgprot_noncached(prot)		__pgprot((pgprot_val(prot) & ~_PAGE_MA_MASK) | _PAGE_MA_UC)
313 #define pgprot_writecombine(prot)	__pgprot((pgprot_val(prot) & ~_PAGE_MA_MASK) | _PAGE_MA_WC)
314 
315 struct file;
316 extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
317 				     unsigned long size, pgprot_t vma_prot);
318 #define __HAVE_PHYS_MEM_ACCESS_PROT
319 
320 static inline unsigned long
321 pgd_index (unsigned long address)
322 {
323 	unsigned long region = address >> 61;
324 	unsigned long l1index = (address >> PGDIR_SHIFT) & ((PTRS_PER_PGD >> 3) - 1);
325 
326 	return (region << (PAGE_SHIFT - 6)) | l1index;
327 }
328 #define pgd_index pgd_index
329 
330 /*
331  * In the kernel's mapped region we know everything is in region number 5, so
332  * as an optimisation its PGD already points to the area for that region.
333  * However, this also means that we cannot use pgd_index() and we must
334  * never add the region here.
335  */
336 #define pgd_offset_k(addr) \
337 	(init_mm.pgd + (((addr) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1)))
338 
339 /* Look up a pgd entry in the gate area.  On IA-64, the gate-area
340    resides in the kernel-mapped segment, hence we use pgd_offset_k()
341    here.  */
342 #define pgd_offset_gate(mm, addr)	pgd_offset_k(addr)
343 
344 /* atomic versions of the some PTE manipulations: */
345 
346 static inline int
347 ptep_test_and_clear_young (struct vm_area_struct *vma, unsigned long addr, pte_t *ptep)
348 {
349 #ifdef CONFIG_SMP
350 	if (!pte_young(*ptep))
351 		return 0;
352 	return test_and_clear_bit(_PAGE_A_BIT, ptep);
353 #else
354 	pte_t pte = *ptep;
355 	if (!pte_young(pte))
356 		return 0;
357 	set_pte_at(vma->vm_mm, addr, ptep, pte_mkold(pte));
358 	return 1;
359 #endif
360 }
361 
362 static inline pte_t
363 ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
364 {
365 #ifdef CONFIG_SMP
366 	return __pte(xchg((long *) ptep, 0));
367 #else
368 	pte_t pte = *ptep;
369 	pte_clear(mm, addr, ptep);
370 	return pte;
371 #endif
372 }
373 
374 static inline void
375 ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
376 {
377 #ifdef CONFIG_SMP
378 	unsigned long new, old;
379 
380 	do {
381 		old = pte_val(*ptep);
382 		new = pte_val(pte_wrprotect(__pte (old)));
383 	} while (cmpxchg((unsigned long *) ptep, old, new) != old);
384 #else
385 	pte_t old_pte = *ptep;
386 	set_pte_at(mm, addr, ptep, pte_wrprotect(old_pte));
387 #endif
388 }
389 
390 static inline int
391 pte_same (pte_t a, pte_t b)
392 {
393 	return pte_val(a) == pte_val(b);
394 }
395 
396 #define update_mmu_cache(vma, address, ptep) do { } while (0)
397 
398 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
399 extern void paging_init (void);
400 
401 /*
402  * Note: The macros below rely on the fact that MAX_SWAPFILES_SHIFT <= number of
403  *	 bits in the swap-type field of the swap pte.  It would be nice to
404  *	 enforce that, but we can't easily include <linux/swap.h> here.
405  *	 (Of course, better still would be to define MAX_SWAPFILES_SHIFT here...).
406  *
407  * Format of swap pte:
408  *	bit   0   : present bit (must be zero)
409  *	bits  1- 7: swap-type
410  *	bits  8-62: swap offset
411  *	bit  63   : _PAGE_PROTNONE bit
412  */
413 #define __swp_type(entry)		(((entry).val >> 1) & 0x7f)
414 #define __swp_offset(entry)		(((entry).val << 1) >> 9)
415 #define __swp_entry(type,offset)	((swp_entry_t) { ((type) << 1) | ((long) (offset) << 8) })
416 #define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) })
417 #define __swp_entry_to_pte(x)		((pte_t) { (x).val })
418 
419 /*
420  * ZERO_PAGE is a global shared page that is always zero: used
421  * for zero-mapped memory areas etc..
422  */
423 extern unsigned long empty_zero_page[PAGE_SIZE/sizeof(unsigned long)];
424 extern struct page *zero_page_memmap_ptr;
425 #define ZERO_PAGE(vaddr) (zero_page_memmap_ptr)
426 
427 /* We provide our own get_unmapped_area to cope with VA holes for userland */
428 #define HAVE_ARCH_UNMAPPED_AREA
429 
430 #ifdef CONFIG_HUGETLB_PAGE
431 #define HUGETLB_PGDIR_SHIFT	(HPAGE_SHIFT + 2*(PAGE_SHIFT-3))
432 #define HUGETLB_PGDIR_SIZE	(__IA64_UL(1) << HUGETLB_PGDIR_SHIFT)
433 #define HUGETLB_PGDIR_MASK	(~(HUGETLB_PGDIR_SIZE-1))
434 #endif
435 
436 
437 #define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
438 /*
439  * Update PTEP with ENTRY, which is guaranteed to be a less
440  * restrictive PTE.  That is, ENTRY may have the ACCESSED, DIRTY, and
441  * WRITABLE bits turned on, when the value at PTEP did not.  The
442  * WRITABLE bit may only be turned if SAFELY_WRITABLE is TRUE.
443  *
444  * SAFELY_WRITABLE is TRUE if we can update the value at PTEP without
445  * having to worry about races.  On SMP machines, there are only two
446  * cases where this is true:
447  *
448  *	(1) *PTEP has the PRESENT bit turned OFF
449  *	(2) ENTRY has the DIRTY bit turned ON
450  *
451  * On ia64, we could implement this routine with a cmpxchg()-loop
452  * which ORs in the _PAGE_A/_PAGE_D bit if they're set in ENTRY.
453  * However, like on x86, we can get a more streamlined version by
454  * observing that it is OK to drop ACCESSED bit updates when
455  * SAFELY_WRITABLE is FALSE.  Besides being rare, all that would do is
456  * result in an extra Access-bit fault, which would then turn on the
457  * ACCESSED bit in the low-level fault handler (iaccess_bit or
458  * daccess_bit in ivt.S).
459  */
460 #ifdef CONFIG_SMP
461 # define ptep_set_access_flags(__vma, __addr, __ptep, __entry, __safely_writable) \
462 ({									\
463 	int __changed = !pte_same(*(__ptep), __entry);			\
464 	if (__changed && __safely_writable) {				\
465 		set_pte(__ptep, __entry);				\
466 		flush_tlb_page(__vma, __addr);				\
467 	}								\
468 	__changed;							\
469 })
470 #else
471 # define ptep_set_access_flags(__vma, __addr, __ptep, __entry, __safely_writable) \
472 ({									\
473 	int __changed = !pte_same(*(__ptep), __entry);			\
474 	if (__changed) {						\
475 		set_pte_at((__vma)->vm_mm, (__addr), __ptep, __entry);	\
476 		flush_tlb_page(__vma, __addr);				\
477 	}								\
478 	__changed;							\
479 })
480 #endif
481 # endif /* !__ASSEMBLY__ */
482 
483 /*
484  * Identity-mapped regions use a large page size.  We'll call such large pages
485  * "granules".  If you can think of a better name that's unambiguous, let me
486  * know...
487  */
488 #if defined(CONFIG_IA64_GRANULE_64MB)
489 # define IA64_GRANULE_SHIFT	_PAGE_SIZE_64M
490 #elif defined(CONFIG_IA64_GRANULE_16MB)
491 # define IA64_GRANULE_SHIFT	_PAGE_SIZE_16M
492 #endif
493 #define IA64_GRANULE_SIZE	(1 << IA64_GRANULE_SHIFT)
494 /*
495  * log2() of the page size we use to map the kernel image (IA64_TR_KERNEL):
496  */
497 #define KERNEL_TR_PAGE_SHIFT	_PAGE_SIZE_64M
498 #define KERNEL_TR_PAGE_SIZE	(1 << KERNEL_TR_PAGE_SHIFT)
499 
500 /* These tell get_user_pages() that the first gate page is accessible from user-level.  */
501 #define FIXADDR_USER_START	GATE_ADDR
502 #ifdef HAVE_BUGGY_SEGREL
503 # define FIXADDR_USER_END	(GATE_ADDR + 2*PAGE_SIZE)
504 #else
505 # define FIXADDR_USER_END	(GATE_ADDR + 2*PERCPU_PAGE_SIZE)
506 #endif
507 
508 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
509 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
510 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
511 #define __HAVE_ARCH_PTE_SAME
512 #define __HAVE_ARCH_PGD_OFFSET_GATE
513 
514 
515 #if CONFIG_PGTABLE_LEVELS == 3
516 #include <asm-generic/pgtable-nopud.h>
517 #endif
518 #include <asm-generic/pgtable-nop4d.h>
519 
520 #endif /* _ASM_IA64_PGTABLE_H */
521