1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ALPHA_PGTABLE_H
3 #define _ALPHA_PGTABLE_H
4
5 #include <asm-generic/pgtable-nopud.h>
6
7 /*
8 * This file contains the functions and defines necessary to modify and use
9 * the Alpha page table tree.
10 *
11 * This hopefully works with any standard Alpha page-size, as defined
12 * in <asm/page.h> (currently 8192).
13 */
14 #include <linux/mmzone.h>
15
16 #include <asm/page.h>
17 #include <asm/processor.h> /* For TASK_SIZE */
18 #include <asm/machvec.h>
19 #include <asm/setup.h>
20
21 struct mm_struct;
22 struct vm_area_struct;
23
24 /* Certain architectures need to do special things when PTEs
25 * within a page table are directly modified. Thus, the following
26 * hook is made available.
27 */
28 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
29 #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
30
31 /* PMD_SHIFT determines the size of the area a second-level page table can map */
32 #define PMD_SHIFT (PAGE_SHIFT + (PAGE_SHIFT-3))
33 #define PMD_SIZE (1UL << PMD_SHIFT)
34 #define PMD_MASK (~(PMD_SIZE-1))
35
36 /* PGDIR_SHIFT determines what a third-level page table entry can map */
37 #define PGDIR_SHIFT (PAGE_SHIFT + 2*(PAGE_SHIFT-3))
38 #define PGDIR_SIZE (1UL << PGDIR_SHIFT)
39 #define PGDIR_MASK (~(PGDIR_SIZE-1))
40
41 /*
42 * Entries per page directory level: the Alpha is three-level, with
43 * all levels having a one-page page table.
44 */
45 #define PTRS_PER_PTE (1UL << (PAGE_SHIFT-3))
46 #define PTRS_PER_PMD (1UL << (PAGE_SHIFT-3))
47 #define PTRS_PER_PGD (1UL << (PAGE_SHIFT-3))
48 #define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
49 #define FIRST_USER_ADDRESS 0UL
50
51 /* Number of pointers that fit on a page: this will go away. */
52 #define PTRS_PER_PAGE (1UL << (PAGE_SHIFT-3))
53
54 #ifdef CONFIG_ALPHA_LARGE_VMALLOC
55 #define VMALLOC_START 0xfffffe0000000000
56 #else
57 #define VMALLOC_START (-2*PGDIR_SIZE)
58 #endif
59 #define VMALLOC_END (-PGDIR_SIZE)
60
61 /*
62 * OSF/1 PAL-code-imposed page table bits
63 */
64 #define _PAGE_VALID 0x0001
65 #define _PAGE_FOR 0x0002 /* used for page protection (fault on read) */
66 #define _PAGE_FOW 0x0004 /* used for page protection (fault on write) */
67 #define _PAGE_FOE 0x0008 /* used for page protection (fault on exec) */
68 #define _PAGE_ASM 0x0010
69 #define _PAGE_KRE 0x0100 /* xxx - see below on the "accessed" bit */
70 #define _PAGE_URE 0x0200 /* xxx */
71 #define _PAGE_KWE 0x1000 /* used to do the dirty bit in software */
72 #define _PAGE_UWE 0x2000 /* used to do the dirty bit in software */
73
74 /* .. and these are ours ... */
75 #define _PAGE_DIRTY 0x20000
76 #define _PAGE_ACCESSED 0x40000
77
78 /*
79 * NOTE! The "accessed" bit isn't necessarily exact: it can be kept exactly
80 * by software (use the KRE/URE/KWE/UWE bits appropriately), but I'll fake it.
81 * Under Linux/AXP, the "accessed" bit just means "read", and I'll just use
82 * the KRE/URE bits to watch for it. That way we don't need to overload the
83 * KWE/UWE bits with both handling dirty and accessed.
84 *
85 * Note that the kernel uses the accessed bit just to check whether to page
86 * out a page or not, so it doesn't have to be exact anyway.
87 */
88
89 #define __DIRTY_BITS (_PAGE_DIRTY | _PAGE_KWE | _PAGE_UWE)
90 #define __ACCESS_BITS (_PAGE_ACCESSED | _PAGE_KRE | _PAGE_URE)
91
92 #define _PFN_MASK 0xFFFFFFFF00000000UL
93
94 #define _PAGE_TABLE (_PAGE_VALID | __DIRTY_BITS | __ACCESS_BITS)
95 #define _PAGE_CHG_MASK (_PFN_MASK | __DIRTY_BITS | __ACCESS_BITS)
96
97 /*
98 * All the normal masks have the "page accessed" bits on, as any time they are used,
99 * the page is accessed. They are cleared only by the page-out routines
100 */
101 #define PAGE_NONE __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOR | _PAGE_FOW | _PAGE_FOE)
102 #define PAGE_SHARED __pgprot(_PAGE_VALID | __ACCESS_BITS)
103 #define PAGE_COPY __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
104 #define PAGE_READONLY __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
105 #define PAGE_KERNEL __pgprot(_PAGE_VALID | _PAGE_ASM | _PAGE_KRE | _PAGE_KWE)
106
107 #define _PAGE_NORMAL(x) __pgprot(_PAGE_VALID | __ACCESS_BITS | (x))
108
109 #define _PAGE_P(x) _PAGE_NORMAL((x) | (((x) & _PAGE_FOW)?0:_PAGE_FOW))
110 #define _PAGE_S(x) _PAGE_NORMAL(x)
111
112 /*
113 * The hardware can handle write-only mappings, but as the Alpha
114 * architecture does byte-wide writes with a read-modify-write
115 * sequence, it's not practical to have write-without-read privs.
116 * Thus the "-w- -> rw-" and "-wx -> rwx" mapping here (and in
117 * arch/alpha/mm/fault.c)
118 */
119 /* xwr */
120 #define __P000 _PAGE_P(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
121 #define __P001 _PAGE_P(_PAGE_FOE | _PAGE_FOW)
122 #define __P010 _PAGE_P(_PAGE_FOE)
123 #define __P011 _PAGE_P(_PAGE_FOE)
124 #define __P100 _PAGE_P(_PAGE_FOW | _PAGE_FOR)
125 #define __P101 _PAGE_P(_PAGE_FOW)
126 #define __P110 _PAGE_P(0)
127 #define __P111 _PAGE_P(0)
128
129 #define __S000 _PAGE_S(_PAGE_FOE | _PAGE_FOW | _PAGE_FOR)
130 #define __S001 _PAGE_S(_PAGE_FOE | _PAGE_FOW)
131 #define __S010 _PAGE_S(_PAGE_FOE)
132 #define __S011 _PAGE_S(_PAGE_FOE)
133 #define __S100 _PAGE_S(_PAGE_FOW | _PAGE_FOR)
134 #define __S101 _PAGE_S(_PAGE_FOW)
135 #define __S110 _PAGE_S(0)
136 #define __S111 _PAGE_S(0)
137
138 /*
139 * pgprot_noncached() is only for infiniband pci support, and a real
140 * implementation for RAM would be more complicated.
141 */
142 #define pgprot_noncached(prot) (prot)
143
144 /*
145 * BAD_PAGETABLE is used when we need a bogus page-table, while
146 * BAD_PAGE is used for a bogus page.
147 *
148 * ZERO_PAGE is a global shared page that is always zero: used
149 * for zero-mapped memory areas etc..
150 */
151 extern pte_t __bad_page(void);
152 extern pmd_t * __bad_pagetable(void);
153
154 extern unsigned long __zero_page(void);
155
156 #define BAD_PAGETABLE __bad_pagetable()
157 #define BAD_PAGE __bad_page()
158 #define ZERO_PAGE(vaddr) (virt_to_page(ZERO_PGE))
159
160 /* number of bits that fit into a memory pointer */
161 #define BITS_PER_PTR (8*sizeof(unsigned long))
162
163 /* to align the pointer to a pointer address */
164 #define PTR_MASK (~(sizeof(void*)-1))
165
166 /* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
167 #define SIZEOF_PTR_LOG2 3
168
169 /* to find an entry in a page-table */
170 #define PAGE_PTR(address) \
171 ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
172
173 /*
174 * On certain platforms whose physical address space can overlap KSEG,
175 * namely EV6 and above, we must re-twiddle the physaddr to restore the
176 * correct high-order bits.
177 *
178 * This is extremely confusing until you realize that this is actually
179 * just working around a userspace bug. The X server was intending to
180 * provide the physical address but instead provided the KSEG address.
181 * Or tried to, except it's not representable.
182 *
183 * On Tsunami there's nothing meaningful at 0x40000000000, so this is
184 * a safe thing to do. Come the first core logic that does put something
185 * in this area -- memory or whathaveyou -- then this hack will have
186 * to go away. So be prepared!
187 */
188
189 #if defined(CONFIG_ALPHA_GENERIC) && defined(USE_48_BIT_KSEG)
190 #error "EV6-only feature in a generic kernel"
191 #endif
192 #if defined(CONFIG_ALPHA_GENERIC) || \
193 (defined(CONFIG_ALPHA_EV6) && !defined(USE_48_BIT_KSEG))
194 #define KSEG_PFN (0xc0000000000UL >> PAGE_SHIFT)
195 #define PHYS_TWIDDLE(pfn) \
196 ((((pfn) & KSEG_PFN) == (0x40000000000UL >> PAGE_SHIFT)) \
197 ? ((pfn) ^= KSEG_PFN) : (pfn))
198 #else
199 #define PHYS_TWIDDLE(pfn) (pfn)
200 #endif
201
202 /*
203 * Conversion functions: convert a page and protection to a page entry,
204 * and a page entry and page directory to the page they refer to.
205 */
206 #define page_to_pa(page) (page_to_pfn(page) << PAGE_SHIFT)
207 #define pte_pfn(pte) (pte_val(pte) >> 32)
208
209 #ifndef CONFIG_DISCONTIGMEM
210 #define pte_page(pte) pfn_to_page(pte_pfn(pte))
211 #define mk_pte(page, pgprot) \
212 ({ \
213 pte_t pte; \
214 \
215 pte_val(pte) = (page_to_pfn(page) << 32) | pgprot_val(pgprot); \
216 pte; \
217 })
218 #endif
219
pfn_pte(unsigned long physpfn,pgprot_t pgprot)220 extern inline pte_t pfn_pte(unsigned long physpfn, pgprot_t pgprot)
221 { pte_t pte; pte_val(pte) = (PHYS_TWIDDLE(physpfn) << 32) | pgprot_val(pgprot); return pte; }
222
pte_modify(pte_t pte,pgprot_t newprot)223 extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
224 { pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
225
pmd_set(pmd_t * pmdp,pte_t * ptep)226 extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
227 { pmd_val(*pmdp) = _PAGE_TABLE | ((((unsigned long) ptep) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
228
pud_set(pud_t * pudp,pmd_t * pmdp)229 extern inline void pud_set(pud_t * pudp, pmd_t * pmdp)
230 { pud_val(*pudp) = _PAGE_TABLE | ((((unsigned long) pmdp) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
231
232
233 extern inline unsigned long
pmd_page_vaddr(pmd_t pmd)234 pmd_page_vaddr(pmd_t pmd)
235 {
236 return ((pmd_val(pmd) & _PFN_MASK) >> (32-PAGE_SHIFT)) + PAGE_OFFSET;
237 }
238
239 #define pmd_page(pmd) (pfn_to_page(pmd_val(pmd) >> 32))
240 #define pud_page(pud) (pfn_to_page(pud_val(pud) >> 32))
241
pud_page_vaddr(pud_t pgd)242 extern inline unsigned long pud_page_vaddr(pud_t pgd)
243 { return PAGE_OFFSET + ((pud_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT)); }
244
pte_none(pte_t pte)245 extern inline int pte_none(pte_t pte) { return !pte_val(pte); }
pte_present(pte_t pte)246 extern inline int pte_present(pte_t pte) { return pte_val(pte) & _PAGE_VALID; }
pte_clear(struct mm_struct * mm,unsigned long addr,pte_t * ptep)247 extern inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
248 {
249 pte_val(*ptep) = 0;
250 }
251
pmd_none(pmd_t pmd)252 extern inline int pmd_none(pmd_t pmd) { return !pmd_val(pmd); }
pmd_bad(pmd_t pmd)253 extern inline int pmd_bad(pmd_t pmd) { return (pmd_val(pmd) & ~_PFN_MASK) != _PAGE_TABLE; }
pmd_present(pmd_t pmd)254 extern inline int pmd_present(pmd_t pmd) { return pmd_val(pmd) & _PAGE_VALID; }
pmd_clear(pmd_t * pmdp)255 extern inline void pmd_clear(pmd_t * pmdp) { pmd_val(*pmdp) = 0; }
256
pud_none(pud_t pud)257 extern inline int pud_none(pud_t pud) { return !pud_val(pud); }
pud_bad(pud_t pud)258 extern inline int pud_bad(pud_t pud) { return (pud_val(pud) & ~_PFN_MASK) != _PAGE_TABLE; }
pud_present(pud_t pud)259 extern inline int pud_present(pud_t pud) { return pud_val(pud) & _PAGE_VALID; }
pud_clear(pud_t * pudp)260 extern inline void pud_clear(pud_t * pudp) { pud_val(*pudp) = 0; }
261
262 /*
263 * The following only work if pte_present() is true.
264 * Undefined behaviour if not..
265 */
pte_write(pte_t pte)266 extern inline int pte_write(pte_t pte) { return !(pte_val(pte) & _PAGE_FOW); }
pte_dirty(pte_t pte)267 extern inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
pte_young(pte_t pte)268 extern inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
269
pte_wrprotect(pte_t pte)270 extern inline pte_t pte_wrprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOW; return pte; }
pte_mkclean(pte_t pte)271 extern inline pte_t pte_mkclean(pte_t pte) { pte_val(pte) &= ~(__DIRTY_BITS); return pte; }
pte_mkold(pte_t pte)272 extern inline pte_t pte_mkold(pte_t pte) { pte_val(pte) &= ~(__ACCESS_BITS); return pte; }
pte_mkwrite(pte_t pte)273 extern inline pte_t pte_mkwrite(pte_t pte) { pte_val(pte) &= ~_PAGE_FOW; return pte; }
pte_mkdirty(pte_t pte)274 extern inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= __DIRTY_BITS; return pte; }
pte_mkyoung(pte_t pte)275 extern inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= __ACCESS_BITS; return pte; }
276
277 /*
278 * The smp_rmb() in the following functions are required to order the load of
279 * *dir (the pointer in the top level page table) with any subsequent load of
280 * the returned pmd_t *ret (ret is data dependent on *dir).
281 *
282 * If this ordering is not enforced, the CPU might load an older value of
283 * *ret, which may be uninitialized data. See mm/memory.c:__pte_alloc for
284 * more details.
285 *
286 * Note that we never change the mm->pgd pointer after the task is running, so
287 * pgd_offset does not require such a barrier.
288 */
289
290 /* Find an entry in the second-level page table.. */
pmd_offset(pud_t * dir,unsigned long address)291 extern inline pmd_t * pmd_offset(pud_t * dir, unsigned long address)
292 {
293 pmd_t *ret = (pmd_t *) pud_page_vaddr(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
294 smp_rmb(); /* see above */
295 return ret;
296 }
297 #define pmd_offset pmd_offset
298
299 /* Find an entry in the third-level page table.. */
pte_offset_kernel(pmd_t * dir,unsigned long address)300 extern inline pte_t * pte_offset_kernel(pmd_t * dir, unsigned long address)
301 {
302 pte_t *ret = (pte_t *) pmd_page_vaddr(*dir)
303 + ((address >> PAGE_SHIFT) & (PTRS_PER_PAGE - 1));
304 smp_rmb(); /* see above */
305 return ret;
306 }
307 #define pte_offset_kernel pte_offset_kernel
308
309 extern pgd_t swapper_pg_dir[1024];
310
311 /*
312 * The Alpha doesn't have any external MMU info: the kernel page
313 * tables contain all the necessary information.
314 */
update_mmu_cache(struct vm_area_struct * vma,unsigned long address,pte_t * ptep)315 extern inline void update_mmu_cache(struct vm_area_struct * vma,
316 unsigned long address, pte_t *ptep)
317 {
318 }
319
320 /*
321 * Non-present pages: high 24 bits are offset, next 8 bits type,
322 * low 32 bits zero.
323 */
mk_swap_pte(unsigned long type,unsigned long offset)324 extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
325 { pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
326
327 #define __swp_type(x) (((x).val >> 32) & 0xff)
328 #define __swp_offset(x) ((x).val >> 40)
329 #define __swp_entry(type, off) ((swp_entry_t) { pte_val(mk_swap_pte((type), (off))) })
330 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
331 #define __swp_entry_to_pte(x) ((pte_t) { (x).val })
332
333 #ifndef CONFIG_DISCONTIGMEM
334 #define kern_addr_valid(addr) (1)
335 #endif
336
337 #define pte_ERROR(e) \
338 printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
339 #define pmd_ERROR(e) \
340 printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
341 #define pgd_ERROR(e) \
342 printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
343
344 extern void paging_init(void);
345
346 /* We have our own get_unmapped_area to cope with ADDR_LIMIT_32BIT. */
347 #define HAVE_ARCH_UNMAPPED_AREA
348
349 #endif /* _ALPHA_PGTABLE_H */
350