1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
4 *
5 * vineetg: May 2011
6 * -Folded PAGE_PRESENT (used by VM) and PAGE_VALID (used by MMU) into 1.
7 * They are semantically the same although in different contexts
8 * VALID marks a TLB entry exists and it will only happen if PRESENT
9 * - Utilise some unused free bits to confine PTE flags to 12 bits
10 * This is a must for 4k pg-sz
11 *
12 * vineetg: Mar 2011 - changes to accommodate MMU TLB Page Descriptor mods
13 * -TLB Locking never really existed, except for initial specs
14 * -SILENT_xxx not needed for our port
15 * -Per my request, MMU V3 changes the layout of some of the bits
16 * to avoid a few shifts in TLB Miss handlers.
17 *
18 * vineetg: April 2010
19 * -PGD entry no longer contains any flags. If empty it is 0, otherwise has
20 * Pg-Tbl ptr. Thus pmd_present(), pmd_valid(), pmd_set( ) become simpler
21 *
22 * vineetg: April 2010
23 * -Switched form 8:11:13 split for page table lookup to 11:8:13
24 * -this speeds up page table allocation itself as we now have to memset 1K
25 * instead of 8k per page table.
26 * -TODO: Right now page table alloc is 8K and rest 7K is unused
27 * need to optimise it
28 *
29 * Amit Bhor, Sameer Dhavale: Codito Technologies 2004
30 */
31
32 #ifndef _ASM_ARC_PGTABLE_H
33 #define _ASM_ARC_PGTABLE_H
34
35 #include <linux/bits.h>
36 #define __ARCH_USE_5LEVEL_HACK
37 #include <asm-generic/pgtable-nopmd.h>
38 #include <asm/page.h>
39 #include <asm/mmu.h> /* to propagate CONFIG_ARC_MMU_VER <n> */
40
41 /**************************************************************************
42 * Page Table Flags
43 *
44 * ARC700 MMU only deals with softare managed TLB entries.
45 * Page Tables are purely for Linux VM's consumption and the bits below are
46 * suited to that (uniqueness). Hence some are not implemented in the TLB and
47 * some have different value in TLB.
48 * e.g. MMU v2: K_READ bit is 8 and so is GLOBAL (possible because they live in
49 * seperate PD0 and PD1, which combined forms a translation entry)
50 * while for PTE perspective, they are 8 and 9 respectively
51 * with MMU v3: Most bits (except SHARED) represent the exact hardware pos
52 * (saves some bit shift ops in TLB Miss hdlrs)
53 */
54
55 #if (CONFIG_ARC_MMU_VER <= 2)
56
57 #define _PAGE_ACCESSED (1<<1) /* Page is accessed (S) */
58 #define _PAGE_CACHEABLE (1<<2) /* Page is cached (H) */
59 #define _PAGE_EXECUTE (1<<3) /* Page has user execute perm (H) */
60 #define _PAGE_WRITE (1<<4) /* Page has user write perm (H) */
61 #define _PAGE_READ (1<<5) /* Page has user read perm (H) */
62 #define _PAGE_DIRTY (1<<6) /* Page modified (dirty) (S) */
63 #define _PAGE_SPECIAL (1<<7)
64 #define _PAGE_GLOBAL (1<<8) /* Page is global (H) */
65 #define _PAGE_PRESENT (1<<10) /* TLB entry is valid (H) */
66
67 #else /* MMU v3 onwards */
68
69 #define _PAGE_CACHEABLE (1<<0) /* Page is cached (H) */
70 #define _PAGE_EXECUTE (1<<1) /* Page has user execute perm (H) */
71 #define _PAGE_WRITE (1<<2) /* Page has user write perm (H) */
72 #define _PAGE_READ (1<<3) /* Page has user read perm (H) */
73 #define _PAGE_ACCESSED (1<<4) /* Page is accessed (S) */
74 #define _PAGE_DIRTY (1<<5) /* Page modified (dirty) (S) */
75 #define _PAGE_SPECIAL (1<<6)
76
77 #if (CONFIG_ARC_MMU_VER >= 4)
78 #define _PAGE_WTHRU (1<<7) /* Page cache mode write-thru (H) */
79 #endif
80
81 #define _PAGE_GLOBAL (1<<8) /* Page is global (H) */
82 #define _PAGE_PRESENT (1<<9) /* TLB entry is valid (H) */
83
84 #if (CONFIG_ARC_MMU_VER >= 4)
85 #define _PAGE_HW_SZ (1<<10) /* Page Size indicator (H): 0 normal, 1 super */
86 #endif
87
88 #define _PAGE_SHARED_CODE (1<<11) /* Shared Code page with cmn vaddr
89 usable for shared TLB entries (H) */
90
91 #define _PAGE_UNUSED_BIT (1<<12)
92 #endif
93
94 /* vmalloc permissions */
95 #define _K_PAGE_PERMS (_PAGE_EXECUTE | _PAGE_WRITE | _PAGE_READ | \
96 _PAGE_GLOBAL | _PAGE_PRESENT)
97
98 #ifndef CONFIG_ARC_CACHE_PAGES
99 #undef _PAGE_CACHEABLE
100 #define _PAGE_CACHEABLE 0
101 #endif
102
103 #ifndef _PAGE_HW_SZ
104 #define _PAGE_HW_SZ 0
105 #endif
106
107 /* Defaults for every user page */
108 #define ___DEF (_PAGE_PRESENT | _PAGE_CACHEABLE)
109
110 /* Set of bits not changed in pte_modify */
111 #define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_SPECIAL)
112
113 /* More Abbrevaited helpers */
114 #define PAGE_U_NONE __pgprot(___DEF)
115 #define PAGE_U_R __pgprot(___DEF | _PAGE_READ)
116 #define PAGE_U_W_R __pgprot(___DEF | _PAGE_READ | _PAGE_WRITE)
117 #define PAGE_U_X_R __pgprot(___DEF | _PAGE_READ | _PAGE_EXECUTE)
118 #define PAGE_U_X_W_R __pgprot(___DEF | _PAGE_READ | _PAGE_WRITE | \
119 _PAGE_EXECUTE)
120
121 #define PAGE_SHARED PAGE_U_W_R
122
123 /* While kernel runs out of unstranslated space, vmalloc/modules use a chunk of
124 * user vaddr space - visible in all addr spaces, but kernel mode only
125 * Thus Global, all-kernel-access, no-user-access, cached
126 */
127 #define PAGE_KERNEL __pgprot(_K_PAGE_PERMS | _PAGE_CACHEABLE)
128
129 /* ioremap */
130 #define PAGE_KERNEL_NO_CACHE __pgprot(_K_PAGE_PERMS)
131
132 /* Masks for actual TLB "PD"s */
133 #define PTE_BITS_IN_PD0 (_PAGE_GLOBAL | _PAGE_PRESENT | _PAGE_HW_SZ)
134 #define PTE_BITS_RWX (_PAGE_EXECUTE | _PAGE_WRITE | _PAGE_READ)
135
136 #ifdef CONFIG_ARC_HAS_PAE40
137 #define PTE_BITS_NON_RWX_IN_PD1 (0xff00000000 | PAGE_MASK | _PAGE_CACHEABLE)
138 #else
139 #define PTE_BITS_NON_RWX_IN_PD1 (PAGE_MASK | _PAGE_CACHEABLE)
140 #endif
141
142 /**************************************************************************
143 * Mapping of vm_flags (Generic VM) to PTE flags (arch specific)
144 *
145 * Certain cases have 1:1 mapping
146 * e.g. __P101 means VM_READ, VM_EXEC and !VM_SHARED
147 * which directly corresponds to PAGE_U_X_R
148 *
149 * Other rules which cause the divergence from 1:1 mapping
150 *
151 * 1. Although ARC700 can do exclusive execute/write protection (meaning R
152 * can be tracked independet of X/W unlike some other CPUs), still to
153 * keep things consistent with other archs:
154 * -Write implies Read: W => R
155 * -Execute implies Read: X => R
156 *
157 * 2. Pvt Writable doesn't have Write Enabled initially: Pvt-W => !W
158 * This is to enable COW mechanism
159 */
160 /* xwr */
161 #define __P000 PAGE_U_NONE
162 #define __P001 PAGE_U_R
163 #define __P010 PAGE_U_R /* Pvt-W => !W */
164 #define __P011 PAGE_U_R /* Pvt-W => !W */
165 #define __P100 PAGE_U_X_R /* X => R */
166 #define __P101 PAGE_U_X_R
167 #define __P110 PAGE_U_X_R /* Pvt-W => !W and X => R */
168 #define __P111 PAGE_U_X_R /* Pvt-W => !W */
169
170 #define __S000 PAGE_U_NONE
171 #define __S001 PAGE_U_R
172 #define __S010 PAGE_U_W_R /* W => R */
173 #define __S011 PAGE_U_W_R
174 #define __S100 PAGE_U_X_R /* X => R */
175 #define __S101 PAGE_U_X_R
176 #define __S110 PAGE_U_X_W_R /* X => R */
177 #define __S111 PAGE_U_X_W_R
178
179 /****************************************************************
180 * 2 tier (PGD:PTE) software page walker
181 *
182 * [31] 32 bit virtual address [0]
183 * -------------------------------------------------------
184 * | | <------------ PGDIR_SHIFT ----------> |
185 * | | |
186 * | BITS_FOR_PGD | BITS_FOR_PTE | <-- PAGE_SHIFT --> |
187 * -------------------------------------------------------
188 * | | |
189 * | | --> off in page frame
190 * | ---> index into Page Table
191 * ----> index into Page Directory
192 *
193 * In a single page size configuration, only PAGE_SHIFT is fixed
194 * So both PGD and PTE sizing can be tweaked
195 * e.g. 8K page (PAGE_SHIFT 13) can have
196 * - PGDIR_SHIFT 21 -> 11:8:13 address split
197 * - PGDIR_SHIFT 24 -> 8:11:13 address split
198 *
199 * If Super Page is configured, PGDIR_SHIFT becomes fixed too,
200 * so the sizing flexibility is gone.
201 */
202
203 #if defined(CONFIG_ARC_HUGEPAGE_16M)
204 #define PGDIR_SHIFT 24
205 #elif defined(CONFIG_ARC_HUGEPAGE_2M)
206 #define PGDIR_SHIFT 21
207 #else
208 /*
209 * Only Normal page support so "hackable" (see comment above)
210 * Default value provides 11:8:13 (8K), 11:9:12 (4K)
211 */
212 #define PGDIR_SHIFT 21
213 #endif
214
215 #define BITS_FOR_PTE (PGDIR_SHIFT - PAGE_SHIFT)
216 #define BITS_FOR_PGD (32 - PGDIR_SHIFT)
217
218 #define PGDIR_SIZE BIT(PGDIR_SHIFT) /* vaddr span, not PDG sz */
219 #define PGDIR_MASK (~(PGDIR_SIZE-1))
220
221 #define PTRS_PER_PTE BIT(BITS_FOR_PTE)
222 #define PTRS_PER_PGD BIT(BITS_FOR_PGD)
223
224 /*
225 * Number of entries a user land program use.
226 * TASK_SIZE is the maximum vaddr that can be used by a userland program.
227 */
228 #define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
229
230 /*
231 * No special requirements for lowest virtual address we permit any user space
232 * mapping to be mapped at.
233 */
234 #define FIRST_USER_ADDRESS 0UL
235
236
237 /****************************************************************
238 * Bucket load of VM Helpers
239 */
240
241 #ifndef __ASSEMBLY__
242
243 #define pte_ERROR(e) \
244 pr_crit("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e))
245 #define pgd_ERROR(e) \
246 pr_crit("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
247
248 /* the zero page used for uninitialized and anonymous pages */
249 extern char empty_zero_page[PAGE_SIZE];
250 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
251
252 #define pte_unmap(pte) do { } while (0)
253 #define pte_unmap_nested(pte) do { } while (0)
254
255 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
256 #define set_pmd(pmdptr, pmdval) (*(pmdptr) = pmdval)
257
258 /* find the page descriptor of the Page Tbl ref by PMD entry */
259 #define pmd_page(pmd) virt_to_page(pmd_val(pmd) & PAGE_MASK)
260
261 /* find the logical addr (phy for ARC) of the Page Tbl ref by PMD entry */
262 #define pmd_page_vaddr(pmd) (pmd_val(pmd) & PAGE_MASK)
263
264 /* In a 2 level sys, setup the PGD entry with PTE value */
pmd_set(pmd_t * pmdp,pte_t * ptep)265 static inline void pmd_set(pmd_t *pmdp, pte_t *ptep)
266 {
267 pmd_val(*pmdp) = (unsigned long)ptep;
268 }
269
270 #define pte_none(x) (!pte_val(x))
271 #define pte_present(x) (pte_val(x) & _PAGE_PRESENT)
272 #define pte_clear(mm, addr, ptep) set_pte_at(mm, addr, ptep, __pte(0))
273
274 #define pmd_none(x) (!pmd_val(x))
275 #define pmd_bad(x) ((pmd_val(x) & ~PAGE_MASK))
276 #define pmd_present(x) (pmd_val(x))
277 #define pmd_clear(xp) do { pmd_val(*(xp)) = 0; } while (0)
278
279 #define pte_page(pte) pfn_to_page(pte_pfn(pte))
280 #define mk_pte(page, prot) pfn_pte(page_to_pfn(page), prot)
281 #define pfn_pte(pfn, prot) __pte(__pfn_to_phys(pfn) | pgprot_val(prot))
282
283 /* Don't use virt_to_pfn for macros below: could cause truncations for PAE40*/
284 #define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT)
285 #define __pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
286
287 /*
288 * pte_offset gets a @ptr to PMD entry (PGD in our 2-tier paging system)
289 * and returns ptr to PTE entry corresponding to @addr
290 */
291 #define pte_offset(dir, addr) ((pte_t *)(pmd_page_vaddr(*dir)) +\
292 __pte_index(addr))
293
294 /* No mapping of Page Tables in high mem etc, so following same as above */
295 #define pte_offset_kernel(dir, addr) pte_offset(dir, addr)
296 #define pte_offset_map(dir, addr) pte_offset(dir, addr)
297
298 /* Zoo of pte_xxx function */
299 #define pte_read(pte) (pte_val(pte) & _PAGE_READ)
300 #define pte_write(pte) (pte_val(pte) & _PAGE_WRITE)
301 #define pte_dirty(pte) (pte_val(pte) & _PAGE_DIRTY)
302 #define pte_young(pte) (pte_val(pte) & _PAGE_ACCESSED)
303 #define pte_special(pte) (pte_val(pte) & _PAGE_SPECIAL)
304
305 #define PTE_BIT_FUNC(fn, op) \
306 static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; }
307
308 PTE_BIT_FUNC(mknotpresent, &= ~(_PAGE_PRESENT));
309 PTE_BIT_FUNC(wrprotect, &= ~(_PAGE_WRITE));
310 PTE_BIT_FUNC(mkwrite, |= (_PAGE_WRITE));
311 PTE_BIT_FUNC(mkclean, &= ~(_PAGE_DIRTY));
312 PTE_BIT_FUNC(mkdirty, |= (_PAGE_DIRTY));
313 PTE_BIT_FUNC(mkold, &= ~(_PAGE_ACCESSED));
314 PTE_BIT_FUNC(mkyoung, |= (_PAGE_ACCESSED));
315 PTE_BIT_FUNC(exprotect, &= ~(_PAGE_EXECUTE));
316 PTE_BIT_FUNC(mkexec, |= (_PAGE_EXECUTE));
317 PTE_BIT_FUNC(mkspecial, |= (_PAGE_SPECIAL));
318 PTE_BIT_FUNC(mkhuge, |= (_PAGE_HW_SZ));
319
pte_modify(pte_t pte,pgprot_t newprot)320 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
321 {
322 return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
323 }
324
325 /* Macro to mark a page protection as uncacheable */
326 #define pgprot_noncached(prot) (__pgprot(pgprot_val(prot) & ~_PAGE_CACHEABLE))
327
set_pte_at(struct mm_struct * mm,unsigned long addr,pte_t * ptep,pte_t pteval)328 static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
329 pte_t *ptep, pte_t pteval)
330 {
331 set_pte(ptep, pteval);
332 }
333
334 /*
335 * All kernel related VM pages are in init's mm.
336 */
337 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
338 #define pgd_index(addr) ((addr) >> PGDIR_SHIFT)
339 #define pgd_offset(mm, addr) (((mm)->pgd)+pgd_index(addr))
340
341 /*
342 * Macro to quickly access the PGD entry, utlising the fact that some
343 * arch may cache the pointer to Page Directory of "current" task
344 * in a MMU register
345 *
346 * Thus task->mm->pgd (3 pointer dereferences, cache misses etc simply
347 * becomes read a register
348 *
349 * ********CAUTION*******:
350 * Kernel code might be dealing with some mm_struct of NON "current"
351 * Thus use this macro only when you are certain that "current" is current
352 * e.g. when dealing with signal frame setup code etc
353 */
354 #ifndef CONFIG_SMP
355 #define pgd_offset_fast(mm, addr) \
356 ({ \
357 pgd_t *pgd_base = (pgd_t *) read_aux_reg(ARC_REG_SCRATCH_DATA0); \
358 pgd_base + pgd_index(addr); \
359 })
360 #else
361 #define pgd_offset_fast(mm, addr) pgd_offset(mm, addr)
362 #endif
363
364 extern pgd_t swapper_pg_dir[] __aligned(PAGE_SIZE);
365 void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
366 pte_t *ptep);
367
368 /* Encode swap {type,off} tuple into PTE
369 * We reserve 13 bits for 5-bit @type, keeping bits 12-5 zero, ensuring that
370 * PAGE_PRESENT is zero in a PTE holding swap "identifier"
371 */
372 #define __swp_entry(type, off) ((swp_entry_t) { \
373 ((type) & 0x1f) | ((off) << 13) })
374
375 /* Decode a PTE containing swap "identifier "into constituents */
376 #define __swp_type(pte_lookalike) (((pte_lookalike).val) & 0x1f)
377 #define __swp_offset(pte_lookalike) ((pte_lookalike).val >> 13)
378
379 /* NOPs, to keep generic kernel happy */
380 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
381 #define __swp_entry_to_pte(x) ((pte_t) { (x).val })
382
383 #define kern_addr_valid(addr) (1)
384
385 /*
386 * remap a physical page `pfn' of size `size' with page protection `prot'
387 * into virtual address `from'
388 */
389 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
390 #include <asm/hugepage.h>
391 #endif
392
393 #include <asm-generic/pgtable.h>
394
395 /* to cope with aliasing VIPT cache */
396 #define HAVE_ARCH_UNMAPPED_AREA
397
398 #endif /* __ASSEMBLY__ */
399
400 #endif
401
