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