1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * include/asm-xtensa/pgtable.h
4 *
5 * Copyright (C) 2001 - 2013 Tensilica Inc.
6 */
7
8 #ifndef _XTENSA_PGTABLE_H
9 #define _XTENSA_PGTABLE_H
10
11 #include <asm/page.h>
12 #include <asm/kmem_layout.h>
13 #include <asm-generic/pgtable-nopmd.h>
14
15 /*
16 * We only use two ring levels, user and kernel space.
17 */
18
19 #ifdef CONFIG_MMU
20 #define USER_RING 1 /* user ring level */
21 #else
22 #define USER_RING 0
23 #endif
24 #define KERNEL_RING 0 /* kernel ring level */
25
26 /*
27 * The Xtensa architecture port of Linux has a two-level page table system,
28 * i.e. the logical three-level Linux page table layout is folded.
29 * Each task has the following memory page tables:
30 *
31 * PGD table (page directory), ie. 3rd-level page table:
32 * One page (4 kB) of 1024 (PTRS_PER_PGD) pointers to PTE tables
33 * (Architectures that don't have the PMD folded point to the PMD tables)
34 *
35 * The pointer to the PGD table for a given task can be retrieved from
36 * the task structure (struct task_struct*) t, e.g. current():
37 * (t->mm ? t->mm : t->active_mm)->pgd
38 *
39 * PMD tables (page middle-directory), ie. 2nd-level page tables:
40 * Absent for the Xtensa architecture (folded, PTRS_PER_PMD == 1).
41 *
42 * PTE tables (page table entry), ie. 1st-level page tables:
43 * One page (4 kB) of 1024 (PTRS_PER_PTE) PTEs with a special PTE
44 * invalid_pte_table for absent mappings.
45 *
46 * The individual pages are 4 kB big with special pages for the empty_zero_page.
47 */
48
49 #define PGDIR_SHIFT 22
50 #define PGDIR_SIZE (1UL << PGDIR_SHIFT)
51 #define PGDIR_MASK (~(PGDIR_SIZE-1))
52
53 /*
54 * Entries per page directory level: we use two-level, so
55 * we don't really have any PMD directory physically.
56 */
57 #define PTRS_PER_PTE 1024
58 #define PTRS_PER_PTE_SHIFT 10
59 #define PTRS_PER_PGD 1024
60 #define USER_PTRS_PER_PGD (TASK_SIZE/PGDIR_SIZE)
61 #define FIRST_USER_PGD_NR (FIRST_USER_ADDRESS >> PGDIR_SHIFT)
62
63 #ifdef CONFIG_MMU
64 /*
65 * Virtual memory area. We keep a distance to other memory regions to be
66 * on the safe side. We also use this area for cache aliasing.
67 */
68 #define VMALLOC_START (XCHAL_KSEG_CACHED_VADDR - 0x10000000)
69 #define VMALLOC_END (VMALLOC_START + 0x07FEFFFF)
70 #define TLBTEMP_BASE_1 (VMALLOC_START + 0x08000000)
71 #define TLBTEMP_BASE_2 (TLBTEMP_BASE_1 + DCACHE_WAY_SIZE)
72 #if 2 * DCACHE_WAY_SIZE > ICACHE_WAY_SIZE
73 #define TLBTEMP_SIZE (2 * DCACHE_WAY_SIZE)
74 #else
75 #define TLBTEMP_SIZE ICACHE_WAY_SIZE
76 #endif
77
78 #else
79
80 #define VMALLOC_START __XTENSA_UL_CONST(0)
81 #define VMALLOC_END __XTENSA_UL_CONST(0xffffffff)
82
83 #endif
84
85 /*
86 * For the Xtensa architecture, the PTE layout is as follows:
87 *
88 * 31------12 11 10-9 8-6 5-4 3-2 1-0
89 * +-----------------------------------------+
90 * | | Software | HARDWARE |
91 * | PPN | ADW | RI |Attribute|
92 * +-----------------------------------------+
93 * pte_none | MBZ | 01 | 11 | 00 |
94 * +-----------------------------------------+
95 * present | PPN | 0 | 00 | ADW | RI | CA | wx |
96 * +- - - - - - - - - - - - - - - - - - - - -+
97 * (PAGE_NONE)| PPN | 0 | 00 | ADW | 01 | 11 | 11 |
98 * +-----------------------------------------+
99 * swap | index | type | 01 | 11 | e0 |
100 * +-----------------------------------------+
101 *
102 * For T1050 hardware and earlier the layout differs for present and (PAGE_NONE)
103 * +-----------------------------------------+
104 * present | PPN | 0 | 00 | ADW | RI | CA | w1 |
105 * +-----------------------------------------+
106 * (PAGE_NONE)| PPN | 0 | 00 | ADW | 01 | 01 | 00 |
107 * +-----------------------------------------+
108 *
109 * Legend:
110 * PPN Physical Page Number
111 * ADW software: accessed (young) / dirty / writable
112 * RI ring (0=privileged, 1=user, 2 and 3 are unused)
113 * CA cache attribute: 00 bypass, 01 writeback, 10 writethrough
114 * (11 is invalid and used to mark pages that are not present)
115 * e exclusive marker in swap PTEs
116 * w page is writable (hw)
117 * x page is executable (hw)
118 * index swap offset / PAGE_SIZE (bit 11-31: 21 bits -> 8 GB)
119 * (note that the index is always non-zero)
120 * type swap type (5 bits -> 32 types)
121 *
122 * Notes:
123 * - (PROT_NONE) is a special case of 'present' but causes an exception for
124 * any access (read, write, and execute).
125 * - 'multihit-exception' has the highest priority of all MMU exceptions,
126 * so the ring must be set to 'RING_USER' even for 'non-present' pages.
127 * - on older hardware, the exectuable flag was not supported and
128 * used as a 'valid' flag, so it needs to be always set.
129 * - we need to keep track of certain flags in software (dirty and young)
130 * to do this, we use write exceptions and have a separate software w-flag.
131 * - attribute value 1101 (and 1111 on T1050 and earlier) is reserved
132 */
133
134 #define _PAGE_ATTRIB_MASK 0xf
135
136 #define _PAGE_HW_EXEC (1<<0) /* hardware: page is executable */
137 #define _PAGE_HW_WRITE (1<<1) /* hardware: page is writable */
138
139 #define _PAGE_CA_BYPASS (0<<2) /* bypass, non-speculative */
140 #define _PAGE_CA_WB (1<<2) /* write-back */
141 #define _PAGE_CA_WT (2<<2) /* write-through */
142 #define _PAGE_CA_MASK (3<<2)
143 #define _PAGE_CA_INVALID (3<<2)
144
145 /* We use invalid attribute values to distinguish special pte entries */
146 #if XCHAL_HW_VERSION_MAJOR < 2000
147 #define _PAGE_HW_VALID 0x01 /* older HW needed this bit set */
148 #define _PAGE_NONE 0x04
149 #else
150 #define _PAGE_HW_VALID 0x00
151 #define _PAGE_NONE 0x0f
152 #endif
153
154 #define _PAGE_USER (1<<4) /* user access (ring=1) */
155
156 /* Software */
157 #define _PAGE_WRITABLE_BIT 6
158 #define _PAGE_WRITABLE (1<<6) /* software: page writable */
159 #define _PAGE_DIRTY (1<<7) /* software: page dirty */
160 #define _PAGE_ACCESSED (1<<8) /* software: page accessed (read) */
161
162 /* We borrow bit 1 to store the exclusive marker in swap PTEs. */
163 #define _PAGE_SWP_EXCLUSIVE (1<<1)
164
165 #ifdef CONFIG_MMU
166
167 #define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
168 #define _PAGE_PRESENT (_PAGE_HW_VALID | _PAGE_CA_WB | _PAGE_ACCESSED)
169
170 #define PAGE_NONE __pgprot(_PAGE_NONE | _PAGE_USER)
171 #define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_USER)
172 #define PAGE_COPY_EXEC __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_HW_EXEC)
173 #define PAGE_READONLY __pgprot(_PAGE_PRESENT | _PAGE_USER)
174 #define PAGE_READONLY_EXEC __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_HW_EXEC)
175 #define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITABLE)
176 #define PAGE_SHARED_EXEC \
177 __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITABLE | _PAGE_HW_EXEC)
178 #define PAGE_KERNEL __pgprot(_PAGE_PRESENT | _PAGE_HW_WRITE)
179 #define PAGE_KERNEL_RO __pgprot(_PAGE_PRESENT)
180 #define PAGE_KERNEL_EXEC __pgprot(_PAGE_PRESENT|_PAGE_HW_WRITE|_PAGE_HW_EXEC)
181
182 #if (DCACHE_WAY_SIZE > PAGE_SIZE)
183 # define _PAGE_DIRECTORY (_PAGE_HW_VALID | _PAGE_ACCESSED | _PAGE_CA_BYPASS)
184 #else
185 # define _PAGE_DIRECTORY (_PAGE_HW_VALID | _PAGE_ACCESSED | _PAGE_CA_WB)
186 #endif
187
188 #else /* no mmu */
189
190 # define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
191 # define PAGE_NONE __pgprot(0)
192 # define PAGE_SHARED __pgprot(0)
193 # define PAGE_COPY __pgprot(0)
194 # define PAGE_READONLY __pgprot(0)
195 # define PAGE_KERNEL __pgprot(0)
196
197 #endif
198
199 /*
200 * On certain configurations of Xtensa MMUs (eg. the initial Linux config),
201 * the MMU can't do page protection for execute, and considers that the same as
202 * read. Also, write permissions may imply read permissions.
203 * What follows is the closest we can get by reasonable means..
204 * See linux/mm/mmap.c for protection_map[] array that uses these definitions.
205 */
206 #ifndef __ASSEMBLY__
207
208 #define pte_ERROR(e) \
209 printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e))
210 #define pgd_ERROR(e) \
211 printk("%s:%d: bad pgd entry %08lx.\n", __FILE__, __LINE__, pgd_val(e))
212
213 extern unsigned long empty_zero_page[1024];
214
215 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
216
217 #ifdef CONFIG_MMU
218 extern pgd_t swapper_pg_dir[PAGE_SIZE/sizeof(pgd_t)];
219 extern void paging_init(void);
220 #else
221 # define swapper_pg_dir NULL
paging_init(void)222 static inline void paging_init(void) { }
223 #endif
224
225 /*
226 * The pmd contains the kernel virtual address of the pte page.
227 */
228 #define pmd_page_vaddr(pmd) ((unsigned long)(pmd_val(pmd) & PAGE_MASK))
229 #define pmd_pfn(pmd) (__pa(pmd_val(pmd)) >> PAGE_SHIFT)
230 #define pmd_page(pmd) virt_to_page(pmd_val(pmd))
231
232 /*
233 * pte status.
234 */
235 # define pte_none(pte) (pte_val(pte) == (_PAGE_CA_INVALID | _PAGE_USER))
236 #if XCHAL_HW_VERSION_MAJOR < 2000
237 # define pte_present(pte) ((pte_val(pte) & _PAGE_CA_MASK) != _PAGE_CA_INVALID)
238 #else
239 # define pte_present(pte) \
240 (((pte_val(pte) & _PAGE_CA_MASK) != _PAGE_CA_INVALID) \
241 || ((pte_val(pte) & _PAGE_ATTRIB_MASK) == _PAGE_NONE))
242 #endif
243 #define pte_clear(mm,addr,ptep) \
244 do { update_pte(ptep, __pte(_PAGE_CA_INVALID | _PAGE_USER)); } while (0)
245
246 #define pmd_none(pmd) (!pmd_val(pmd))
247 #define pmd_present(pmd) (pmd_val(pmd) & PAGE_MASK)
248 #define pmd_bad(pmd) (pmd_val(pmd) & ~PAGE_MASK)
249 #define pmd_clear(pmdp) do { set_pmd(pmdp, __pmd(0)); } while (0)
250
pte_write(pte_t pte)251 static inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_WRITABLE; }
pte_dirty(pte_t pte)252 static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
pte_young(pte_t pte)253 static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
254
pte_wrprotect(pte_t pte)255 static inline pte_t pte_wrprotect(pte_t pte)
256 { pte_val(pte) &= ~(_PAGE_WRITABLE | _PAGE_HW_WRITE); return pte; }
pte_mkclean(pte_t pte)257 static inline pte_t pte_mkclean(pte_t pte)
258 { pte_val(pte) &= ~(_PAGE_DIRTY | _PAGE_HW_WRITE); return pte; }
pte_mkold(pte_t pte)259 static inline pte_t pte_mkold(pte_t pte)
260 { pte_val(pte) &= ~_PAGE_ACCESSED; return pte; }
pte_mkdirty(pte_t pte)261 static inline pte_t pte_mkdirty(pte_t pte)
262 { pte_val(pte) |= _PAGE_DIRTY; return pte; }
pte_mkyoung(pte_t pte)263 static inline pte_t pte_mkyoung(pte_t pte)
264 { pte_val(pte) |= _PAGE_ACCESSED; return pte; }
pte_mkwrite_novma(pte_t pte)265 static inline pte_t pte_mkwrite_novma(pte_t pte)
266 { pte_val(pte) |= _PAGE_WRITABLE; return pte; }
267
268 #define pgprot_noncached(prot) \
269 ((__pgprot((pgprot_val(prot) & ~_PAGE_CA_MASK) | \
270 _PAGE_CA_BYPASS)))
271
272 /*
273 * Conversion functions: convert a page and protection to a page entry,
274 * and a page entry and page directory to the page they refer to.
275 */
276
277 #define PFN_PTE_SHIFT PAGE_SHIFT
278 #define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT)
279 #define pte_same(a,b) (pte_val(a) == pte_val(b))
280 #define pte_page(x) pfn_to_page(pte_pfn(x))
281 #define pfn_pte(pfn, prot) __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
282 #define mk_pte(page, prot) pfn_pte(page_to_pfn(page), prot)
283
pte_modify(pte_t pte,pgprot_t newprot)284 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
285 {
286 return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
287 }
288
289 /*
290 * Certain architectures need to do special things when pte's
291 * within a page table are directly modified. Thus, the following
292 * hook is made available.
293 */
update_pte(pte_t * ptep,pte_t pteval)294 static inline void update_pte(pte_t *ptep, pte_t pteval)
295 {
296 *ptep = pteval;
297 #if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK
298 __asm__ __volatile__ ("dhwb %0, 0" :: "a" (ptep));
299 #endif
300
301 }
302
303 struct mm_struct;
304
set_pte(pte_t * ptep,pte_t pte)305 static inline void set_pte(pte_t *ptep, pte_t pte)
306 {
307 update_pte(ptep, pte);
308 }
309
310 static inline void
set_pmd(pmd_t * pmdp,pmd_t pmdval)311 set_pmd(pmd_t *pmdp, pmd_t pmdval)
312 {
313 *pmdp = pmdval;
314 }
315
316 struct vm_area_struct;
317
318 static inline int
ptep_test_and_clear_young(struct vm_area_struct * vma,unsigned long addr,pte_t * ptep)319 ptep_test_and_clear_young(struct vm_area_struct *vma, unsigned long addr,
320 pte_t *ptep)
321 {
322 pte_t pte = *ptep;
323 if (!pte_young(pte))
324 return 0;
325 update_pte(ptep, pte_mkold(pte));
326 return 1;
327 }
328
329 static inline pte_t
ptep_get_and_clear(struct mm_struct * mm,unsigned long addr,pte_t * ptep)330 ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
331 {
332 pte_t pte = *ptep;
333 pte_clear(mm, addr, ptep);
334 return pte;
335 }
336
337 static inline void
ptep_set_wrprotect(struct mm_struct * mm,unsigned long addr,pte_t * ptep)338 ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
339 {
340 pte_t pte = *ptep;
341 update_pte(ptep, pte_wrprotect(pte));
342 }
343
344 /*
345 * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
346 * are !pte_none() && !pte_present().
347 */
348 #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > 5)
349
350 #define __swp_type(entry) (((entry).val >> 6) & 0x1f)
351 #define __swp_offset(entry) ((entry).val >> 11)
352 #define __swp_entry(type,offs) \
353 ((swp_entry_t){(((type) & 0x1f) << 6) | ((offs) << 11) | \
354 _PAGE_CA_INVALID | _PAGE_USER})
355 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
356 #define __swp_entry_to_pte(x) ((pte_t) { (x).val })
357
pte_swp_exclusive(pte_t pte)358 static inline int pte_swp_exclusive(pte_t pte)
359 {
360 return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
361 }
362
pte_swp_mkexclusive(pte_t pte)363 static inline pte_t pte_swp_mkexclusive(pte_t pte)
364 {
365 pte_val(pte) |= _PAGE_SWP_EXCLUSIVE;
366 return pte;
367 }
368
pte_swp_clear_exclusive(pte_t pte)369 static inline pte_t pte_swp_clear_exclusive(pte_t pte)
370 {
371 pte_val(pte) &= ~_PAGE_SWP_EXCLUSIVE;
372 return pte;
373 }
374
375 #endif /* !defined (__ASSEMBLY__) */
376
377
378 #ifdef __ASSEMBLY__
379
380 /* Assembly macro _PGD_INDEX is the same as C pgd_index(unsigned long),
381 * _PGD_OFFSET as C pgd_offset(struct mm_struct*, unsigned long),
382 * _PMD_OFFSET as C pmd_offset(pgd_t*, unsigned long)
383 * _PTE_OFFSET as C pte_offset(pmd_t*, unsigned long)
384 *
385 * Note: We require an additional temporary register which can be the same as
386 * the register that holds the address.
387 *
388 * ((pte_t*) ((unsigned long)(pmd_val(*pmd) & PAGE_MASK)) + pte_index(addr))
389 *
390 */
391 #define _PGD_INDEX(rt,rs) extui rt, rs, PGDIR_SHIFT, 32-PGDIR_SHIFT
392 #define _PTE_INDEX(rt,rs) extui rt, rs, PAGE_SHIFT, PTRS_PER_PTE_SHIFT
393
394 #define _PGD_OFFSET(mm,adr,tmp) l32i mm, mm, MM_PGD; \
395 _PGD_INDEX(tmp, adr); \
396 addx4 mm, tmp, mm
397
398 #define _PTE_OFFSET(pmd,adr,tmp) _PTE_INDEX(tmp, adr); \
399 srli pmd, pmd, PAGE_SHIFT; \
400 slli pmd, pmd, PAGE_SHIFT; \
401 addx4 pmd, tmp, pmd
402
403 #else
404
405 struct vm_fault;
406 void update_mmu_cache_range(struct vm_fault *vmf, struct vm_area_struct *vma,
407 unsigned long address, pte_t *ptep, unsigned int nr);
408 #define update_mmu_cache(vma, address, ptep) \
409 update_mmu_cache_range(NULL, vma, address, ptep, 1)
410
411 typedef pte_t *pte_addr_t;
412
413 void update_mmu_tlb(struct vm_area_struct *vma,
414 unsigned long address, pte_t *ptep);
415 #define __HAVE_ARCH_UPDATE_MMU_TLB
416
417 #endif /* !defined (__ASSEMBLY__) */
418
419 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
420 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
421 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
422 #define __HAVE_ARCH_PTEP_MKDIRTY
423 #define __HAVE_ARCH_PTE_SAME
424 /* We provide our own get_unmapped_area to cope with
425 * SHM area cache aliasing for userland.
426 */
427 #define HAVE_ARCH_UNMAPPED_AREA
428
429 #endif /* _XTENSA_PGTABLE_H */
430