1#ifndef __ASM_SH_PGTABLE_32_H
2#define __ASM_SH_PGTABLE_32_H
3
4/*
5 * Linux PTEL encoding.
6 *
7 * Hardware and software bit definitions for the PTEL value (see below for
8 * notes on SH-X2 MMUs and 64-bit PTEs):
9 *
10 * - Bits 0 and 7 are reserved on SH-3 (_PAGE_WT and _PAGE_SZ1 on SH-4).
11 *
12 * - Bit 1 is the SH-bit, but is unused on SH-3 due to an MMU bug (the
13 *   hardware PTEL value can't have the SH-bit set when MMUCR.IX is set,
14 *   which is the default in cpu-sh3/mmu_context.h:MMU_CONTROL_INIT).
15 *
16 *   In order to keep this relatively clean, do not use these for defining
17 *   SH-3 specific flags until all of the other unused bits have been
18 *   exhausted.
19 *
20 * - Bit 9 is reserved by everyone and used by _PAGE_PROTNONE.
21 *
22 * - Bits 10 and 11 are low bits of the PPN that are reserved on >= 4K pages.
23 *   Bit 10 is used for _PAGE_ACCESSED, and bit 11 is used for _PAGE_SPECIAL.
24 *
25 * - On 29 bit platforms, bits 31 to 29 are used for the space attributes
26 *   and timing control which (together with bit 0) are moved into the
27 *   old-style PTEA on the parts that support it.
28 *
29 * SH-X2 MMUs and extended PTEs
30 *
31 * SH-X2 supports an extended mode TLB with split data arrays due to the
32 * number of bits needed for PR and SZ (now EPR and ESZ) encodings. The PR and
33 * SZ bit placeholders still exist in data array 1, but are implemented as
34 * reserved bits, with the real logic existing in data array 2.
35 *
36 * The downside to this is that we can no longer fit everything in to a 32-bit
37 * PTE encoding, so a 64-bit pte_t is necessary for these parts. On the plus
38 * side, this gives us quite a few spare bits to play with for future usage.
39 */
40/* Legacy and compat mode bits */
41#define	_PAGE_WT	0x001		/* WT-bit on SH-4, 0 on SH-3 */
42#define _PAGE_HW_SHARED	0x002		/* SH-bit  : shared among processes */
43#define _PAGE_DIRTY	0x004		/* D-bit   : page changed */
44#define _PAGE_CACHABLE	0x008		/* C-bit   : cachable */
45#define _PAGE_SZ0	0x010		/* SZ0-bit : Size of page */
46#define _PAGE_RW	0x020		/* PR0-bit : write access allowed */
47#define _PAGE_USER	0x040		/* PR1-bit : user space access allowed*/
48#define _PAGE_SZ1	0x080		/* SZ1-bit : Size of page (on SH-4) */
49#define _PAGE_PRESENT	0x100		/* V-bit   : page is valid */
50#define _PAGE_PROTNONE	0x200		/* software: if not present  */
51#define _PAGE_ACCESSED	0x400		/* software: page referenced */
52#define _PAGE_SPECIAL	0x800		/* software: special page */
53
54#define _PAGE_SZ_MASK	(_PAGE_SZ0 | _PAGE_SZ1)
55#define _PAGE_PR_MASK	(_PAGE_RW | _PAGE_USER)
56
57/* Extended mode bits */
58#define _PAGE_EXT_ESZ0		0x0010	/* ESZ0-bit: Size of page */
59#define _PAGE_EXT_ESZ1		0x0020	/* ESZ1-bit: Size of page */
60#define _PAGE_EXT_ESZ2		0x0040	/* ESZ2-bit: Size of page */
61#define _PAGE_EXT_ESZ3		0x0080	/* ESZ3-bit: Size of page */
62
63#define _PAGE_EXT_USER_EXEC	0x0100	/* EPR0-bit: User space executable */
64#define _PAGE_EXT_USER_WRITE	0x0200	/* EPR1-bit: User space writable */
65#define _PAGE_EXT_USER_READ	0x0400	/* EPR2-bit: User space readable */
66
67#define _PAGE_EXT_KERN_EXEC	0x0800	/* EPR3-bit: Kernel space executable */
68#define _PAGE_EXT_KERN_WRITE	0x1000	/* EPR4-bit: Kernel space writable */
69#define _PAGE_EXT_KERN_READ	0x2000	/* EPR5-bit: Kernel space readable */
70
71#define _PAGE_EXT_WIRED		0x4000	/* software: Wire TLB entry */
72
73/* Wrapper for extended mode pgprot twiddling */
74#define _PAGE_EXT(x)		((unsigned long long)(x) << 32)
75
76#ifdef CONFIG_X2TLB
77#define _PAGE_PCC_MASK	0x00000000	/* No legacy PTEA support */
78#else
79
80/* software: moves to PTEA.TC (Timing Control) */
81#define _PAGE_PCC_AREA5	0x00000000	/* use BSC registers for area5 */
82#define _PAGE_PCC_AREA6	0x80000000	/* use BSC registers for area6 */
83
84/* software: moves to PTEA.SA[2:0] (Space Attributes) */
85#define _PAGE_PCC_IODYN 0x00000001	/* IO space, dynamically sized bus */
86#define _PAGE_PCC_IO8	0x20000000	/* IO space, 8 bit bus */
87#define _PAGE_PCC_IO16	0x20000001	/* IO space, 16 bit bus */
88#define _PAGE_PCC_COM8	0x40000000	/* Common Memory space, 8 bit bus */
89#define _PAGE_PCC_COM16	0x40000001	/* Common Memory space, 16 bit bus */
90#define _PAGE_PCC_ATR8	0x60000000	/* Attribute Memory space, 8 bit bus */
91#define _PAGE_PCC_ATR16	0x60000001	/* Attribute Memory space, 6 bit bus */
92
93#define _PAGE_PCC_MASK	0xe0000001
94
95/* copy the ptea attributes */
96static inline unsigned long copy_ptea_attributes(unsigned long x)
97{
98	return	((x >> 28) & 0xe) | (x & 0x1);
99}
100#endif
101
102/* Mask which drops unused bits from the PTEL value */
103#if defined(CONFIG_CPU_SH3)
104#define _PAGE_CLEAR_FLAGS	(_PAGE_PROTNONE | _PAGE_ACCESSED| \
105				  _PAGE_SZ1	| _PAGE_HW_SHARED)
106#elif defined(CONFIG_X2TLB)
107/* Get rid of the legacy PR/SZ bits when using extended mode */
108#define _PAGE_CLEAR_FLAGS	(_PAGE_PROTNONE | _PAGE_ACCESSED | \
109				 _PAGE_PR_MASK | _PAGE_SZ_MASK)
110#else
111#define _PAGE_CLEAR_FLAGS	(_PAGE_PROTNONE | _PAGE_ACCESSED)
112#endif
113
114#define _PAGE_FLAGS_HARDWARE_MASK	(phys_addr_mask() & ~(_PAGE_CLEAR_FLAGS))
115
116/* Hardware flags, page size encoding */
117#if !defined(CONFIG_MMU)
118# define _PAGE_FLAGS_HARD	0ULL
119#elif defined(CONFIG_X2TLB)
120# if defined(CONFIG_PAGE_SIZE_4KB)
121#  define _PAGE_FLAGS_HARD	_PAGE_EXT(_PAGE_EXT_ESZ0)
122# elif defined(CONFIG_PAGE_SIZE_8KB)
123#  define _PAGE_FLAGS_HARD	_PAGE_EXT(_PAGE_EXT_ESZ1)
124# elif defined(CONFIG_PAGE_SIZE_64KB)
125#  define _PAGE_FLAGS_HARD	_PAGE_EXT(_PAGE_EXT_ESZ2)
126# endif
127#else
128# if defined(CONFIG_PAGE_SIZE_4KB)
129#  define _PAGE_FLAGS_HARD	_PAGE_SZ0
130# elif defined(CONFIG_PAGE_SIZE_64KB)
131#  define _PAGE_FLAGS_HARD	_PAGE_SZ1
132# endif
133#endif
134
135#if defined(CONFIG_X2TLB)
136# if defined(CONFIG_HUGETLB_PAGE_SIZE_64K)
137#  define _PAGE_SZHUGE	(_PAGE_EXT_ESZ2)
138# elif defined(CONFIG_HUGETLB_PAGE_SIZE_256K)
139#  define _PAGE_SZHUGE	(_PAGE_EXT_ESZ0 | _PAGE_EXT_ESZ2)
140# elif defined(CONFIG_HUGETLB_PAGE_SIZE_1MB)
141#  define _PAGE_SZHUGE	(_PAGE_EXT_ESZ0 | _PAGE_EXT_ESZ1 | _PAGE_EXT_ESZ2)
142# elif defined(CONFIG_HUGETLB_PAGE_SIZE_4MB)
143#  define _PAGE_SZHUGE	(_PAGE_EXT_ESZ3)
144# elif defined(CONFIG_HUGETLB_PAGE_SIZE_64MB)
145#  define _PAGE_SZHUGE	(_PAGE_EXT_ESZ2 | _PAGE_EXT_ESZ3)
146# endif
147# define _PAGE_WIRED	(_PAGE_EXT(_PAGE_EXT_WIRED))
148#else
149# if defined(CONFIG_HUGETLB_PAGE_SIZE_64K)
150#  define _PAGE_SZHUGE	(_PAGE_SZ1)
151# elif defined(CONFIG_HUGETLB_PAGE_SIZE_1MB)
152#  define _PAGE_SZHUGE	(_PAGE_SZ0 | _PAGE_SZ1)
153# endif
154# define _PAGE_WIRED	(0)
155#endif
156
157/*
158 * Stub out _PAGE_SZHUGE if we don't have a good definition for it,
159 * to make pte_mkhuge() happy.
160 */
161#ifndef _PAGE_SZHUGE
162# define _PAGE_SZHUGE	(_PAGE_FLAGS_HARD)
163#endif
164
165/*
166 * Mask of bits that are to be preserved across pgprot changes.
167 */
168#define _PAGE_CHG_MASK \
169	(PTE_MASK | _PAGE_ACCESSED | _PAGE_CACHABLE | \
170	 _PAGE_DIRTY | _PAGE_SPECIAL)
171
172#ifndef __ASSEMBLY__
173
174#if defined(CONFIG_X2TLB) /* SH-X2 TLB */
175#define PAGE_NONE	__pgprot(_PAGE_PROTNONE | _PAGE_CACHABLE | \
176				 _PAGE_ACCESSED | _PAGE_FLAGS_HARD)
177
178#define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \
179				 _PAGE_CACHABLE | _PAGE_FLAGS_HARD | \
180				 _PAGE_EXT(_PAGE_EXT_KERN_READ  | \
181					   _PAGE_EXT_KERN_WRITE | \
182					   _PAGE_EXT_USER_READ  | \
183					   _PAGE_EXT_USER_WRITE))
184
185#define PAGE_EXECREAD	__pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \
186				 _PAGE_CACHABLE | _PAGE_FLAGS_HARD | \
187				 _PAGE_EXT(_PAGE_EXT_KERN_EXEC | \
188					   _PAGE_EXT_KERN_READ | \
189					   _PAGE_EXT_USER_EXEC | \
190					   _PAGE_EXT_USER_READ))
191
192#define PAGE_COPY	PAGE_EXECREAD
193
194#define PAGE_READONLY	__pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \
195				 _PAGE_CACHABLE | _PAGE_FLAGS_HARD | \
196				 _PAGE_EXT(_PAGE_EXT_KERN_READ | \
197					   _PAGE_EXT_USER_READ))
198
199#define PAGE_WRITEONLY	__pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \
200				 _PAGE_CACHABLE | _PAGE_FLAGS_HARD | \
201				 _PAGE_EXT(_PAGE_EXT_KERN_WRITE | \
202					   _PAGE_EXT_USER_WRITE))
203
204#define PAGE_RWX	__pgprot(_PAGE_PRESENT | _PAGE_ACCESSED | \
205				 _PAGE_CACHABLE | _PAGE_FLAGS_HARD | \
206				 _PAGE_EXT(_PAGE_EXT_KERN_WRITE | \
207					   _PAGE_EXT_KERN_READ  | \
208					   _PAGE_EXT_KERN_EXEC  | \
209					   _PAGE_EXT_USER_WRITE | \
210					   _PAGE_EXT_USER_READ  | \
211					   _PAGE_EXT_USER_EXEC))
212
213#define PAGE_KERNEL	__pgprot(_PAGE_PRESENT | _PAGE_CACHABLE | \
214				 _PAGE_DIRTY | _PAGE_ACCESSED | \
215				 _PAGE_HW_SHARED | _PAGE_FLAGS_HARD | \
216				 _PAGE_EXT(_PAGE_EXT_KERN_READ | \
217					   _PAGE_EXT_KERN_WRITE | \
218					   _PAGE_EXT_KERN_EXEC))
219
220#define PAGE_KERNEL_NOCACHE \
221			__pgprot(_PAGE_PRESENT | _PAGE_DIRTY | \
222				 _PAGE_ACCESSED | _PAGE_HW_SHARED | \
223				 _PAGE_FLAGS_HARD | \
224				 _PAGE_EXT(_PAGE_EXT_KERN_READ | \
225					   _PAGE_EXT_KERN_WRITE | \
226					   _PAGE_EXT_KERN_EXEC))
227
228#define PAGE_KERNEL_RO	__pgprot(_PAGE_PRESENT | _PAGE_CACHABLE | \
229				 _PAGE_DIRTY | _PAGE_ACCESSED | \
230				 _PAGE_HW_SHARED | _PAGE_FLAGS_HARD | \
231				 _PAGE_EXT(_PAGE_EXT_KERN_READ | \
232					   _PAGE_EXT_KERN_EXEC))
233
234#define PAGE_KERNEL_PCC(slot, type) \
235			__pgprot(0)
236
237#elif defined(CONFIG_MMU) /* SH-X TLB */
238#define PAGE_NONE	__pgprot(_PAGE_PROTNONE | _PAGE_CACHABLE | \
239				 _PAGE_ACCESSED | _PAGE_FLAGS_HARD)
240
241#define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | \
242				 _PAGE_CACHABLE | _PAGE_ACCESSED | \
243				 _PAGE_FLAGS_HARD)
244
245#define PAGE_COPY	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_CACHABLE | \
246				 _PAGE_ACCESSED | _PAGE_FLAGS_HARD)
247
248#define PAGE_READONLY	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_CACHABLE | \
249				 _PAGE_ACCESSED | _PAGE_FLAGS_HARD)
250
251#define PAGE_EXECREAD	PAGE_READONLY
252#define PAGE_RWX	PAGE_SHARED
253#define PAGE_WRITEONLY	PAGE_SHARED
254
255#define PAGE_KERNEL	__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_CACHABLE | \
256				 _PAGE_DIRTY | _PAGE_ACCESSED | \
257				 _PAGE_HW_SHARED | _PAGE_FLAGS_HARD)
258
259#define PAGE_KERNEL_NOCACHE \
260			__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | \
261				 _PAGE_ACCESSED | _PAGE_HW_SHARED | \
262				 _PAGE_FLAGS_HARD)
263
264#define PAGE_KERNEL_RO	__pgprot(_PAGE_PRESENT | _PAGE_CACHABLE | \
265				 _PAGE_DIRTY | _PAGE_ACCESSED | \
266				 _PAGE_HW_SHARED | _PAGE_FLAGS_HARD)
267
268#define PAGE_KERNEL_PCC(slot, type) \
269			__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | \
270				 _PAGE_ACCESSED | _PAGE_FLAGS_HARD | \
271				 (slot ? _PAGE_PCC_AREA5 : _PAGE_PCC_AREA6) | \
272				 (type))
273#else /* no mmu */
274#define PAGE_NONE		__pgprot(0)
275#define PAGE_SHARED		__pgprot(0)
276#define PAGE_COPY		__pgprot(0)
277#define PAGE_EXECREAD		__pgprot(0)
278#define PAGE_RWX		__pgprot(0)
279#define PAGE_READONLY		__pgprot(0)
280#define PAGE_WRITEONLY		__pgprot(0)
281#define PAGE_KERNEL		__pgprot(0)
282#define PAGE_KERNEL_NOCACHE	__pgprot(0)
283#define PAGE_KERNEL_RO		__pgprot(0)
284
285#define PAGE_KERNEL_PCC(slot, type) \
286				__pgprot(0)
287#endif
288
289#endif /* __ASSEMBLY__ */
290
291#ifndef __ASSEMBLY__
292
293/*
294 * Certain architectures need to do special things when PTEs
295 * within a page table are directly modified.  Thus, the following
296 * hook is made available.
297 */
298#ifdef CONFIG_X2TLB
299static inline void set_pte(pte_t *ptep, pte_t pte)
300{
301	ptep->pte_high = pte.pte_high;
302	smp_wmb();
303	ptep->pte_low = pte.pte_low;
304}
305#else
306#define set_pte(pteptr, pteval) (*(pteptr) = pteval)
307#endif
308
309#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
310
311/*
312 * (pmds are folded into pgds so this doesn't get actually called,
313 * but the define is needed for a generic inline function.)
314 */
315#define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval)
316
317#define pfn_pte(pfn, prot) \
318	__pte(((unsigned long long)(pfn) << PAGE_SHIFT) | pgprot_val(prot))
319#define pfn_pmd(pfn, prot) \
320	__pmd(((unsigned long long)(pfn) << PAGE_SHIFT) | pgprot_val(prot))
321
322#define pte_none(x)		(!pte_val(x))
323#define pte_present(x)		((x).pte_low & (_PAGE_PRESENT | _PAGE_PROTNONE))
324
325#define pte_clear(mm,addr,xp) do { set_pte_at(mm, addr, xp, __pte(0)); } while (0)
326
327#define pmd_none(x)	(!pmd_val(x))
328#define pmd_present(x)	(pmd_val(x))
329#define pmd_clear(xp)	do { set_pmd(xp, __pmd(0)); } while (0)
330#define	pmd_bad(x)	(pmd_val(x) & ~PAGE_MASK)
331
332#define pages_to_mb(x)	((x) >> (20-PAGE_SHIFT))
333#define pte_page(x)	pfn_to_page(pte_pfn(x))
334
335/*
336 * The following only work if pte_present() is true.
337 * Undefined behaviour if not..
338 */
339#define pte_not_present(pte)	(!((pte).pte_low & _PAGE_PRESENT))
340#define pte_dirty(pte)		((pte).pte_low & _PAGE_DIRTY)
341#define pte_young(pte)		((pte).pte_low & _PAGE_ACCESSED)
342#define pte_special(pte)	((pte).pte_low & _PAGE_SPECIAL)
343
344#ifdef CONFIG_X2TLB
345#define pte_write(pte) \
346	((pte).pte_high & (_PAGE_EXT_USER_WRITE | _PAGE_EXT_KERN_WRITE))
347#else
348#define pte_write(pte)		((pte).pte_low & _PAGE_RW)
349#endif
350
351#define PTE_BIT_FUNC(h,fn,op) \
352static inline pte_t pte_##fn(pte_t pte) { pte.pte_##h op; return pte; }
353
354#ifdef CONFIG_X2TLB
355/*
356 * We cheat a bit in the SH-X2 TLB case. As the permission bits are
357 * individually toggled (and user permissions are entirely decoupled from
358 * kernel permissions), we attempt to couple them a bit more sanely here.
359 */
360PTE_BIT_FUNC(high, wrprotect, &= ~(_PAGE_EXT_USER_WRITE | _PAGE_EXT_KERN_WRITE));
361PTE_BIT_FUNC(high, mkwrite, |= _PAGE_EXT_USER_WRITE | _PAGE_EXT_KERN_WRITE);
362PTE_BIT_FUNC(high, mkhuge, |= _PAGE_SZHUGE);
363#else
364PTE_BIT_FUNC(low, wrprotect, &= ~_PAGE_RW);
365PTE_BIT_FUNC(low, mkwrite, |= _PAGE_RW);
366PTE_BIT_FUNC(low, mkhuge, |= _PAGE_SZHUGE);
367#endif
368
369PTE_BIT_FUNC(low, mkclean, &= ~_PAGE_DIRTY);
370PTE_BIT_FUNC(low, mkdirty, |= _PAGE_DIRTY);
371PTE_BIT_FUNC(low, mkold, &= ~_PAGE_ACCESSED);
372PTE_BIT_FUNC(low, mkyoung, |= _PAGE_ACCESSED);
373PTE_BIT_FUNC(low, mkspecial, |= _PAGE_SPECIAL);
374
375/*
376 * Macro and implementation to make a page protection as uncachable.
377 */
378#define pgprot_writecombine(prot) \
379	__pgprot(pgprot_val(prot) & ~_PAGE_CACHABLE)
380
381#define pgprot_noncached	 pgprot_writecombine
382
383/*
384 * Conversion functions: convert a page and protection to a page entry,
385 * and a page entry and page directory to the page they refer to.
386 *
387 * extern pte_t mk_pte(struct page *page, pgprot_t pgprot)
388 */
389#define mk_pte(page, pgprot)	pfn_pte(page_to_pfn(page), (pgprot))
390
391static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
392{
393	pte.pte_low &= _PAGE_CHG_MASK;
394	pte.pte_low |= pgprot_val(newprot);
395
396#ifdef CONFIG_X2TLB
397	pte.pte_high |= pgprot_val(newprot) >> 32;
398#endif
399
400	return pte;
401}
402
403#define pmd_page_vaddr(pmd)	((unsigned long)pmd_val(pmd))
404#define pmd_page(pmd)		(virt_to_page(pmd_val(pmd)))
405
406/* to find an entry in a page-table-directory. */
407#define pgd_index(address)	(((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
408#define pgd_offset(mm, address)	((mm)->pgd + pgd_index(address))
409#define __pgd_offset(address)	pgd_index(address)
410
411/* to find an entry in a kernel page-table-directory */
412#define pgd_offset_k(address)	pgd_offset(&init_mm, address)
413
414#define __pud_offset(address)	(((address) >> PUD_SHIFT) & (PTRS_PER_PUD-1))
415#define __pmd_offset(address)	(((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
416
417/* Find an entry in the third-level page table.. */
418#define pte_index(address)	((address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
419#define __pte_offset(address)	pte_index(address)
420
421#define pte_offset_kernel(dir, address) \
422	((pte_t *) pmd_page_vaddr(*(dir)) + pte_index(address))
423#define pte_offset_map(dir, address)		pte_offset_kernel(dir, address)
424#define pte_unmap(pte)		do { } while (0)
425
426#ifdef CONFIG_X2TLB
427#define pte_ERROR(e) \
428	printk("%s:%d: bad pte %p(%08lx%08lx).\n", __FILE__, __LINE__, \
429	       &(e), (e).pte_high, (e).pte_low)
430#define pgd_ERROR(e) \
431	printk("%s:%d: bad pgd %016llx.\n", __FILE__, __LINE__, pgd_val(e))
432#else
433#define pte_ERROR(e) \
434	printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e))
435#define pgd_ERROR(e) \
436	printk("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
437#endif
438
439/*
440 * Encode and de-code a swap entry
441 *
442 * Constraints:
443 *	_PAGE_PRESENT at bit 8
444 *	_PAGE_PROTNONE at bit 9
445 *
446 * For the normal case, we encode the swap type into bits 0:7 and the
447 * swap offset into bits 10:30. For the 64-bit PTE case, we keep the
448 * preserved bits in the low 32-bits and use the upper 32 as the swap
449 * offset (along with a 5-bit type), following the same approach as x86
450 * PAE. This keeps the logic quite simple.
451 *
452 * As is evident by the Alpha code, if we ever get a 64-bit unsigned
453 * long (swp_entry_t) to match up with the 64-bit PTEs, this all becomes
454 * much cleaner..
455 *
456 * NOTE: We should set ZEROs at the position of _PAGE_PRESENT
457 *       and _PAGE_PROTNONE bits
458 */
459#ifdef CONFIG_X2TLB
460#define __swp_type(x)			((x).val & 0x1f)
461#define __swp_offset(x)			((x).val >> 5)
462#define __swp_entry(type, offset)	((swp_entry_t){ (type) | (offset) << 5})
463#define __pte_to_swp_entry(pte)		((swp_entry_t){ (pte).pte_high })
464#define __swp_entry_to_pte(x)		((pte_t){ 0, (x).val })
465
466#else
467#define __swp_type(x)			((x).val & 0xff)
468#define __swp_offset(x)			((x).val >> 10)
469#define __swp_entry(type, offset)	((swp_entry_t){(type) | (offset) <<10})
470
471#define __pte_to_swp_entry(pte)		((swp_entry_t) { pte_val(pte) >> 1 })
472#define __swp_entry_to_pte(x)		((pte_t) { (x).val << 1 })
473#endif
474
475#endif /* __ASSEMBLY__ */
476#endif /* __ASM_SH_PGTABLE_32_H */
477