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1#ifndef _I386_PGTABLE_H
2#define _I386_PGTABLE_H
3
4
5/*
6 * The Linux memory management assumes a three-level page table setup. On
7 * the i386, we use that, but "fold" the mid level into the top-level page
8 * table, so that we physically have the same two-level page table as the
9 * i386 mmu expects.
10 *
11 * This file contains the functions and defines necessary to modify and use
12 * the i386 page table tree.
13 */
14#ifndef __ASSEMBLY__
15#include <asm/processor.h>
16#include <asm/fixmap.h>
17#include <linux/threads.h>
18#include <asm/paravirt.h>
19
20#ifndef _I386_BITOPS_H
21#include <asm/bitops.h>
22#endif
23
24#include <linux/slab.h>
25#include <linux/list.h>
26#include <linux/spinlock.h>
27
28struct mm_struct;
29struct vm_area_struct;
30
31/*
32 * ZERO_PAGE is a global shared page that is always zero: used
33 * for zero-mapped memory areas etc..
34 */
35#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
36extern unsigned long empty_zero_page[1024];
37extern pgd_t swapper_pg_dir[1024];
38extern struct kmem_cache *pmd_cache;
39extern spinlock_t pgd_lock;
40extern struct page *pgd_list;
41void check_pgt_cache(void);
42
43void pmd_ctor(void *, struct kmem_cache *, unsigned long);
44void pgtable_cache_init(void);
45void paging_init(void);
46
47
48/*
49 * The Linux x86 paging architecture is 'compile-time dual-mode', it
50 * implements both the traditional 2-level x86 page tables and the
51 * newer 3-level PAE-mode page tables.
52 */
53#ifdef CONFIG_X86_PAE
54# include <asm/pgtable-3level-defs.h>
55# define PMD_SIZE (1UL << PMD_SHIFT)
56# define PMD_MASK (~(PMD_SIZE-1))
57#else
58# include <asm/pgtable-2level-defs.h>
59#endif
60
61#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
62#define PGDIR_MASK (~(PGDIR_SIZE-1))
63
64#define USER_PTRS_PER_PGD (TASK_SIZE/PGDIR_SIZE)
65#define FIRST_USER_ADDRESS 0
66
67#define USER_PGD_PTRS (PAGE_OFFSET >> PGDIR_SHIFT)
68#define KERNEL_PGD_PTRS (PTRS_PER_PGD-USER_PGD_PTRS)
69
70#define TWOLEVEL_PGDIR_SHIFT 22
71#define BOOT_USER_PGD_PTRS (__PAGE_OFFSET >> TWOLEVEL_PGDIR_SHIFT)
72#define BOOT_KERNEL_PGD_PTRS (1024-BOOT_USER_PGD_PTRS)
73
74/* Just any arbitrary offset to the start of the vmalloc VM area: the
75 * current 8MB value just means that there will be a 8MB "hole" after the
76 * physical memory until the kernel virtual memory starts. That means that
77 * any out-of-bounds memory accesses will hopefully be caught.
78 * The vmalloc() routines leaves a hole of 4kB between each vmalloced
79 * area for the same reason. ;)
80 */
81#define VMALLOC_OFFSET (8*1024*1024)
82#define VMALLOC_START (((unsigned long) high_memory + \
83 2*VMALLOC_OFFSET-1) & ~(VMALLOC_OFFSET-1))
84#ifdef CONFIG_HIGHMEM
85# define VMALLOC_END (PKMAP_BASE-2*PAGE_SIZE)
86#else
87# define VMALLOC_END (FIXADDR_START-2*PAGE_SIZE)
88#endif
89
90/*
91 * _PAGE_PSE set in the page directory entry just means that
92 * the page directory entry points directly to a 4MB-aligned block of
93 * memory.
94 */
95#define _PAGE_BIT_PRESENT 0
96#define _PAGE_BIT_RW 1
97#define _PAGE_BIT_USER 2
98#define _PAGE_BIT_PWT 3
99#define _PAGE_BIT_PCD 4
100#define _PAGE_BIT_ACCESSED 5
101#define _PAGE_BIT_DIRTY 6
102#define _PAGE_BIT_PSE 7 /* 4 MB (or 2MB) page, Pentium+, if present.. */
103#define _PAGE_BIT_GLOBAL 8 /* Global TLB entry PPro+ */
104#define _PAGE_BIT_UNUSED1 9 /* available for programmer */
105#define _PAGE_BIT_UNUSED2 10
106#define _PAGE_BIT_UNUSED3 11
107#define _PAGE_BIT_NX 63
108
109#define _PAGE_PRESENT 0x001
110#define _PAGE_RW 0x002
111#define _PAGE_USER 0x004
112#define _PAGE_PWT 0x008
113#define _PAGE_PCD 0x010
114#define _PAGE_ACCESSED 0x020
115#define _PAGE_DIRTY 0x040
116#define _PAGE_PSE 0x080 /* 4 MB (or 2MB) page, Pentium+, if present.. */
117#define _PAGE_GLOBAL 0x100 /* Global TLB entry PPro+ */
118#define _PAGE_UNUSED1 0x200 /* available for programmer */
119#define _PAGE_UNUSED2 0x400
120#define _PAGE_UNUSED3 0x800
121
122/* If _PAGE_PRESENT is clear, we use these: */
123#define _PAGE_FILE 0x040 /* nonlinear file mapping, saved PTE; unset:swap */
124#define _PAGE_PROTNONE 0x080 /* if the user mapped it with PROT_NONE;
125 pte_present gives true */
126#ifdef CONFIG_X86_PAE
127#define _PAGE_NX (1ULL<<_PAGE_BIT_NX)
128#else
129#define _PAGE_NX 0
130#endif
131
132#define _PAGE_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED | _PAGE_DIRTY)
133#define _KERNPG_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
134#define _PAGE_CHG_MASK (PTE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
135
136#define PAGE_NONE \
137 __pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)
138#define PAGE_SHARED \
139 __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED)
140
141#define PAGE_SHARED_EXEC \
142 __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | _PAGE_ACCESSED)
143#define PAGE_COPY_NOEXEC \
144 __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED | _PAGE_NX)
145#define PAGE_COPY_EXEC \
146 __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
147#define PAGE_COPY \
148 PAGE_COPY_NOEXEC
149#define PAGE_READONLY \
150 __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED | _PAGE_NX)
151#define PAGE_READONLY_EXEC \
152 __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
153
154#define _PAGE_KERNEL \
155 (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_NX)
156#define _PAGE_KERNEL_EXEC \
157 (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)
158
159extern unsigned long long __PAGE_KERNEL, __PAGE_KERNEL_EXEC;
160#define __PAGE_KERNEL_RO (__PAGE_KERNEL & ~_PAGE_RW)
161#define __PAGE_KERNEL_RX (__PAGE_KERNEL_EXEC & ~_PAGE_RW)
162#define __PAGE_KERNEL_NOCACHE (__PAGE_KERNEL | _PAGE_PCD)
163#define __PAGE_KERNEL_LARGE (__PAGE_KERNEL | _PAGE_PSE)
164#define __PAGE_KERNEL_LARGE_EXEC (__PAGE_KERNEL_EXEC | _PAGE_PSE)
165
166#define PAGE_KERNEL __pgprot(__PAGE_KERNEL)
167#define PAGE_KERNEL_RO __pgprot(__PAGE_KERNEL_RO)
168#define PAGE_KERNEL_EXEC __pgprot(__PAGE_KERNEL_EXEC)
169#define PAGE_KERNEL_RX __pgprot(__PAGE_KERNEL_RX)
170#define PAGE_KERNEL_NOCACHE __pgprot(__PAGE_KERNEL_NOCACHE)
171#define PAGE_KERNEL_LARGE __pgprot(__PAGE_KERNEL_LARGE)
172#define PAGE_KERNEL_LARGE_EXEC __pgprot(__PAGE_KERNEL_LARGE_EXEC)
173
174/*
175 * The i386 can't do page protection for execute, and considers that
176 * the same are read. Also, write permissions imply read permissions.
177 * This is the closest we can get..
178 */
179#define __P000 PAGE_NONE
180#define __P001 PAGE_READONLY
181#define __P010 PAGE_COPY
182#define __P011 PAGE_COPY
183#define __P100 PAGE_READONLY_EXEC
184#define __P101 PAGE_READONLY_EXEC
185#define __P110 PAGE_COPY_EXEC
186#define __P111 PAGE_COPY_EXEC
187
188#define __S000 PAGE_NONE
189#define __S001 PAGE_READONLY
190#define __S010 PAGE_SHARED
191#define __S011 PAGE_SHARED
192#define __S100 PAGE_READONLY_EXEC
193#define __S101 PAGE_READONLY_EXEC
194#define __S110 PAGE_SHARED_EXEC
195#define __S111 PAGE_SHARED_EXEC
196
197/*
198 * Define this if things work differently on an i386 and an i486:
199 * it will (on an i486) warn about kernel memory accesses that are
200 * done without a 'access_ok(VERIFY_WRITE,..)'
201 */
202#undef TEST_ACCESS_OK
203
204/* The boot page tables (all created as a single array) */
205extern unsigned long pg0[];
206
207#define pte_present(x) ((x).pte_low & (_PAGE_PRESENT | _PAGE_PROTNONE))
208
209/* To avoid harmful races, pmd_none(x) should check only the lower when PAE */
210#define pmd_none(x) (!(unsigned long)pmd_val(x))
211#define pmd_present(x) (pmd_val(x) & _PAGE_PRESENT)
212#define pmd_bad(x) ((pmd_val(x) & (~PAGE_MASK & ~_PAGE_USER)) != _KERNPG_TABLE)
213
214
215#define pages_to_mb(x) ((x) >> (20-PAGE_SHIFT))
216
217/*
218 * The following only work if pte_present() is true.
219 * Undefined behaviour if not..
220 */
221static inline int pte_dirty(pte_t pte) { return (pte).pte_low & _PAGE_DIRTY; }
222static inline int pte_young(pte_t pte) { return (pte).pte_low & _PAGE_ACCESSED; }
223static inline int pte_write(pte_t pte) { return (pte).pte_low & _PAGE_RW; }
224static inline int pte_huge(pte_t pte) { return (pte).pte_low & _PAGE_PSE; }
225
226/*
227 * The following only works if pte_present() is not true.
228 */
229static inline int pte_file(pte_t pte) { return (pte).pte_low & _PAGE_FILE; }
230
231static inline pte_t pte_mkclean(pte_t pte) { (pte).pte_low &= ~_PAGE_DIRTY; return pte; }
232static inline pte_t pte_mkold(pte_t pte) { (pte).pte_low &= ~_PAGE_ACCESSED; return pte; }
233static inline pte_t pte_wrprotect(pte_t pte) { (pte).pte_low &= ~_PAGE_RW; return pte; }
234static inline pte_t pte_mkdirty(pte_t pte) { (pte).pte_low |= _PAGE_DIRTY; return pte; }
235static inline pte_t pte_mkyoung(pte_t pte) { (pte).pte_low |= _PAGE_ACCESSED; return pte; }
236static inline pte_t pte_mkwrite(pte_t pte) { (pte).pte_low |= _PAGE_RW; return pte; }
237static inline pte_t pte_mkhuge(pte_t pte) { (pte).pte_low |= _PAGE_PSE; return pte; }
238
239#ifdef CONFIG_X86_PAE
240# include <asm/pgtable-3level.h>
241#else
242# include <asm/pgtable-2level.h>
243#endif
244
245#ifndef CONFIG_PARAVIRT
246/*
247 * Rules for using pte_update - it must be called after any PTE update which
248 * has not been done using the set_pte / clear_pte interfaces. It is used by
249 * shadow mode hypervisors to resynchronize the shadow page tables. Kernel PTE
250 * updates should either be sets, clears, or set_pte_atomic for P->P
251 * transitions, which means this hook should only be called for user PTEs.
252 * This hook implies a P->P protection or access change has taken place, which
253 * requires a subsequent TLB flush. The notification can optionally be delayed
254 * until the TLB flush event by using the pte_update_defer form of the
255 * interface, but care must be taken to assure that the flush happens while
256 * still holding the same page table lock so that the shadow and primary pages
257 * do not become out of sync on SMP.
258 */
259#define pte_update(mm, addr, ptep) do { } while (0)
260#define pte_update_defer(mm, addr, ptep) do { } while (0)
261#endif
262
263/* local pte updates need not use xchg for locking */
264static inline pte_t native_local_ptep_get_and_clear(pte_t *ptep)
265{
266 pte_t res = *ptep;
267
268 /* Pure native function needs no input for mm, addr */
269 native_pte_clear(NULL, 0, ptep);
270 return res;
271}
272
273/*
274 * We only update the dirty/accessed state if we set
275 * the dirty bit by hand in the kernel, since the hardware
276 * will do the accessed bit for us, and we don't want to
277 * race with other CPU's that might be updating the dirty
278 * bit at the same time.
279 */
280#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
281#define ptep_set_access_flags(vma, address, ptep, entry, dirty) \
282({ \
283 int __changed = !pte_same(*(ptep), entry); \
284 if (__changed && dirty) { \
285 (ptep)->pte_low = (entry).pte_low; \
286 pte_update_defer((vma)->vm_mm, (address), (ptep)); \
287 flush_tlb_page(vma, address); \
288 } \
289 __changed; \
290})
291
292#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
293#define ptep_test_and_clear_young(vma, addr, ptep) ({ \
294 int __ret = 0; \
295 if (pte_young(*(ptep))) \
296 __ret = test_and_clear_bit(_PAGE_BIT_ACCESSED, \
297 &(ptep)->pte_low); \
298 if (__ret) \
299 pte_update((vma)->vm_mm, addr, ptep); \
300 __ret; \
301})
302
303#define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
304#define ptep_clear_flush_young(vma, address, ptep) \
305({ \
306 int __young; \
307 __young = ptep_test_and_clear_young((vma), (address), (ptep)); \
308 if (__young) \
309 flush_tlb_page(vma, address); \
310 __young; \
311})
312
313#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
314static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
315{
316 pte_t pte = native_ptep_get_and_clear(ptep);
317 pte_update(mm, addr, ptep);
318 return pte;
319}
320
321#define __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
322static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm, unsigned long addr, pte_t *ptep, int full)
323{
324 pte_t pte;
325 if (full) {
326 /*
327 * Full address destruction in progress; paravirt does not
328 * care about updates and native needs no locking
329 */
330 pte = native_local_ptep_get_and_clear(ptep);
331 } else {
332 pte = ptep_get_and_clear(mm, addr, ptep);
333 }
334 return pte;
335}
336
337#define __HAVE_ARCH_PTEP_SET_WRPROTECT
338static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
339{
340 clear_bit(_PAGE_BIT_RW, &ptep->pte_low);
341 pte_update(mm, addr, ptep);
342}
343
344/*
345 * clone_pgd_range(pgd_t *dst, pgd_t *src, int count);
346 *
347 * dst - pointer to pgd range anwhere on a pgd page
348 * src - ""
349 * count - the number of pgds to copy.
350 *
351 * dst and src can be on the same page, but the range must not overlap,
352 * and must not cross a page boundary.
353 */
354static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count)
355{
356 memcpy(dst, src, count * sizeof(pgd_t));
357}
358
359/*
360 * Macro to mark a page protection value as "uncacheable". On processors which do not support
361 * it, this is a no-op.
362 */
363#define pgprot_noncached(prot) ((boot_cpu_data.x86 > 3) \
364 ? (__pgprot(pgprot_val(prot) | _PAGE_PCD | _PAGE_PWT)) : (prot))
365
366/*
367 * Conversion functions: convert a page and protection to a page entry,
368 * and a page entry and page directory to the page they refer to.
369 */
370
371#define mk_pte(page, pgprot) pfn_pte(page_to_pfn(page), (pgprot))
372
373static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
374{
375 pte.pte_low &= _PAGE_CHG_MASK;
376 pte.pte_low |= pgprot_val(newprot);
377#ifdef CONFIG_X86_PAE
378 /*
379 * Chop off the NX bit (if present), and add the NX portion of
380 * the newprot (if present):
381 */
382 pte.pte_high &= ~(1 << (_PAGE_BIT_NX - 32));
383 pte.pte_high |= (pgprot_val(newprot) >> 32) & \
384 (__supported_pte_mask >> 32);
385#endif
386 return pte;
387}
388
389#define pmd_large(pmd) \
390((pmd_val(pmd) & (_PAGE_PSE|_PAGE_PRESENT)) == (_PAGE_PSE|_PAGE_PRESENT))
391
392/*
393 * the pgd page can be thought of an array like this: pgd_t[PTRS_PER_PGD]
394 *
395 * this macro returns the index of the entry in the pgd page which would
396 * control the given virtual address
397 */
398#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
399#define pgd_index_k(addr) pgd_index(addr)
400
401/*
402 * pgd_offset() returns a (pgd_t *)
403 * pgd_index() is used get the offset into the pgd page's array of pgd_t's;
404 */
405#define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
406
407/*
408 * a shortcut which implies the use of the kernel's pgd, instead
409 * of a process's
410 */
411#define pgd_offset_k(address) pgd_offset(&init_mm, address)
412
413/*
414 * the pmd page can be thought of an array like this: pmd_t[PTRS_PER_PMD]
415 *
416 * this macro returns the index of the entry in the pmd page which would
417 * control the given virtual address
418 */
419#define pmd_index(address) \
420 (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
421
422/*
423 * the pte page can be thought of an array like this: pte_t[PTRS_PER_PTE]
424 *
425 * this macro returns the index of the entry in the pte page which would
426 * control the given virtual address
427 */
428#define pte_index(address) \
429 (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
430#define pte_offset_kernel(dir, address) \
431 ((pte_t *) pmd_page_vaddr(*(dir)) + pte_index(address))
432
433#define pmd_page(pmd) (pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
434
435#define pmd_page_vaddr(pmd) \
436 ((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
437
438/*
439 * Helper function that returns the kernel pagetable entry controlling
440 * the virtual address 'address'. NULL means no pagetable entry present.
441 * NOTE: the return type is pte_t but if the pmd is PSE then we return it
442 * as a pte too.
443 */
444extern pte_t *lookup_address(unsigned long address);
445
446/*
447 * Make a given kernel text page executable/non-executable.
448 * Returns the previous executability setting of that page (which
449 * is used to restore the previous state). Used by the SMP bootup code.
450 * NOTE: this is an __init function for security reasons.
451 */
452#ifdef CONFIG_X86_PAE
453 extern int set_kernel_exec(unsigned long vaddr, int enable);
454#else
455 static inline int set_kernel_exec(unsigned long vaddr, int enable) { return 0;}
456#endif
457
458#if defined(CONFIG_HIGHPTE)
459#define pte_offset_map(dir, address) \
460 ((pte_t *)kmap_atomic_pte(pmd_page(*(dir)),KM_PTE0) + pte_index(address))
461#define pte_offset_map_nested(dir, address) \
462 ((pte_t *)kmap_atomic_pte(pmd_page(*(dir)),KM_PTE1) + pte_index(address))
463#define pte_unmap(pte) kunmap_atomic(pte, KM_PTE0)
464#define pte_unmap_nested(pte) kunmap_atomic(pte, KM_PTE1)
465#else
466#define pte_offset_map(dir, address) \
467 ((pte_t *)page_address(pmd_page(*(dir))) + pte_index(address))
468#define pte_offset_map_nested(dir, address) pte_offset_map(dir, address)
469#define pte_unmap(pte) do { } while (0)
470#define pte_unmap_nested(pte) do { } while (0)
471#endif
472
473/* Clear a kernel PTE and flush it from the TLB */
474#define kpte_clear_flush(ptep, vaddr) \
475do { \
476 pte_clear(&init_mm, vaddr, ptep); \
477 __flush_tlb_one(vaddr); \
478} while (0)
479
480/*
481 * The i386 doesn't have any external MMU info: the kernel page
482 * tables contain all the necessary information.
483 */
484#define update_mmu_cache(vma,address,pte) do { } while (0)
485
486void native_pagetable_setup_start(pgd_t *base);
487void native_pagetable_setup_done(pgd_t *base);
488
489#ifndef CONFIG_PARAVIRT
490static inline void paravirt_pagetable_setup_start(pgd_t *base)
491{
492 native_pagetable_setup_start(base);
493}
494
495static inline void paravirt_pagetable_setup_done(pgd_t *base)
496{
497 native_pagetable_setup_done(base);
498}
499#endif /* !CONFIG_PARAVIRT */
500
501#endif /* !__ASSEMBLY__ */
502
503#ifdef CONFIG_FLATMEM
504#define kern_addr_valid(addr) (1)
505#endif /* CONFIG_FLATMEM */
506
507#define io_remap_pfn_range(vma, vaddr, pfn, size, prot) \
508 remap_pfn_range(vma, vaddr, pfn, size, prot)
509
510#include <asm-generic/pgtable.h>
511
512#endif /* _I386_PGTABLE_H */